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w.. e. t xn��wNr �.`�' .-®e. �a •�� � se35L0.y ..s�"�"r 6� 1 goo Y The Renton Treatment Plant Effluent Transfer System Outfall Project '"'&METRO Candidate for: ASCE Outstanding Civil Engineering Achievement Award 1987 The Municipality of Metropolitan Seattle a I :�-Mr=TRO Technical Services Department Cover photo&raph: Metro,M.S. 61 Outfall pipeline near Seattle's Duwamish Head. 821 Second Ave. Seattle,WA 98104-1598 January 1988 i i I i Abstract j The Renton Treatment Plant Effluent Transfer System Outfall Project is well qualified for recognition by the American Society of Civil Engineers as an Outstanding Civil Engineering Achievement. The following characteristics demonstrate how this project meets the selection criteria for this award: Contribution to the well-being of people and communities The system eliminated the discharge of secondary effluent into the Duwamish River thereby protecting a valuable salmon fisheries resource. Resourcefulness in planning and solution of design problems The outfall is the deepest in the world. Its design was based on oil and gas offshore technology. Value-engineering studies validated the engineering criteria. Pioneering in the use of materials and methods The outfall pipe,diffusers and other long-lead items were procured separately by the owner.The pipe itself is the world's largest-diameter mill-rolled pipe. A specially designed tool was used to up-set holes for the diffuser ports. Welding procedures were developed to weld copper-nickel alloy nozzles to the ports on the high-tensile-strength carbon steel pipe. A polyurethane abrasion-resistant coating was applied over fusion-bonded epoxy pipe-protective coating. Innovation in construction The contractor proposed a segmented offshore installation method using bolted flanges and designed and manufactured a special tool for the underwater bolt-up assembly. Compliance with allowable stress limits were verified by an on-site dynamic,computer stress analysis program. Environmental impacts, unusual aspects, aesthetic value Environmental and other impacts were minimized by the outfall location and depth.Scientific studies aided in the selection of the outfall location and depth. A baseline study was made before construction to provide data for the long-term impacts of the effluent discharge.The outfall installation was scheduled to protect fish migration. Possible adverse impacts Near-shore trench excavation could have caused underwater cave-ins and landslides. Overwater towing of the pipe segments and lay barge positioning and anchoring might have interfered with navigation. Handling and lowering of the long pipe segments presented potential overstress problems. Failure of the underwater bolt-up tool could have seriously jeopardized the projects successful completion. I I Metro's Renton Treatment Plant Effluent Transfer System Outf all Project Introduction � m4 One of two outfall pipelines Is lowered Into Elliott Bay at Duwamish Head.(Courtesy of Engineering News-Record) The Aug. 21,1986,issue of Engineering News-Record Second,the program required the skills and tech- featured a story on the Municipality of Metropolitan nologies of a wide variety of physical science and en- Seattle's Renton Treatment Plant Expansion Program, gineering disciplines,including geology,metallurgy, with a special emphasis on the program's effluent archaeology,oceanography,soil mechanics,struc- transfer system outfall project. The program and out- tural engineering, traffic engineering,rotating equiF fall project received that nationwide coverage for a ment and mechanical engineering,and control sys- variety of reasons. Here are two principal reasons. tems engineering. The construction-engineering tech- niques included state-of-the-art robotics. First,Metro carried out the program in a unique way. Unique in that Metro departed from some of the Construction of the outfall for the effluent transfer traditional methods of contracting for and managing system was the most technologically diverse and public works projects. Metro management and staff challenging part of the program.To give a perspec- played a very proactive role in managing and coor- five to the outfall project and its relationship to other dinating the engineering design,procurement and parts of the effluent transfer system,here is an over- construction of all elements of the program.The view of the total$325 million Renton Expansion program was truly fast-tracked.There were 24 equip- Prograrm ment supply and construction contracts phased into this program during an approximate 60-month period.At the peak,however,20 procurements and contracts were under way during an 18-month period. 1 Background In the early 1980s,Metro planners determined that, fer treatment plant effluent from the Duwamish to because of population growth projections for the Ren- the marine waters of Puget Sound through a large- ton Treatment Plant service area,the plant should be diameter onshore pipeline and outfall.The on-land expanded to a capacity of 72 million gallons per day corridor routing,location and depth of the marine outfall were authorized by the Metro Council, This expansion would double the plant's capacity. In Metro's governing body,on April 7, 1984. addition,Metro determined that the plant should have its own solids-or sludge-processing and han- dling facilities. �F The Renton plant's secondary treated effluent has al- ways been good in quality,but its increasing high volume of discharges into the Duwamish River in- czeased the potential for harm to one of Washington state's most important and productive salmon and steelhead resources,with a value of more than$10 million annually.Several fish hatcheries along the The Duwamish River supports the largest salmon and river are a major source of Chinook and coho salmon steeihead runs to Washington state. for Puget Sound. During the summer when flows are low,up to 25 percent of the Duwamish flows had To comply with the Department of Ecology's 1987 been treated effluent.If the Renton plant continued compliance milestone in that short period of time, to discharge into the river, that percentage would in- Metro determined that separate design,procurement crease to about 50 percent during dry-weather flows and construction packages for the ETS project should by the year 2000. In approving Metro's facilities plan be developed for the three major components: the for the plant expansion,the Washington State Depart- pumping station,onshore force main and outfall. For ment of Ecology specified that the plant's effluent each component,the design,procurement and con- could no longer be discharged into the Duwamish. struction packages were carefully scoped,scheduled, The Department of Ecology established a Jan. 1, 1987, controlled and coordinated to fit together in a very deadline for removing effluent from the river. complex project implementation,completion and start-up plan. The Department of Ecology's requirement resulted in the definition and scope of a project that would trans- XV 5 # �~►� 4 Metro's Renton Treatment Plant provides secondary treatment for up to 72 million gallons per day. 2 Pumping station I i 6 t - r i d � i $ert R t. : q w A 2,560-horsepower peaking pump is installed in the effluent pumping station. The pumping station,which is designed for a dis- contracted with Mitsubishi Corp.to manufacture the charge head of 150 feet,consists of four low-head or pumps. The pumps,drives and motors were normal-duty 650-horsepower pumps and four high- manufactured at five different facilities in Japan. head or peaking 2,560-horsepower pumps.The Electrical transformers were fabricated in Toshiba's pumping station was designed to allow expansion to Houston,Texas,plant. Metro received the pumping pump an ultimate peak flow of 325 mgd with an equipment beginning in May 1986. It was then average daily flow of 144 mgd!The pumps recently turned over to the installation contractor,installed, installed and commissioned have capacity for the cur- tested and made ready for initial operation by rent treatment plant expansion of peak flows of 230 December 1986. mgd with an average daily flow of 72 mgd.The pumping station is fully automated except for pump The pumping station was built using four construc- start-up and shutdown, which require an operator. tion contracts: two for site work at a total value of The pumps use variable-speed drives tied to wet- $1.64 million, one for substructure work at a value of well level sensors for control. $1.24 million and one for superstructure and pump j installation at a value of$8.8 million.Site preparation II Metro's design consultant,the URS Corp.,specified work began in late 1984,and the total pumping sta- the pumps,motors and drives. Metro purchased all tion component of the ETS project was substantially of the equipment,which was then supplied to the in- completed in February1987 at a total cost of about stallation contractor as a single"owner-furnished" $18.3 million,including engineering and Metro costs. package.The$3.9 million purchase order was placed in February 1985 with Toshiba Corp.Toshiba manufactured the motors and drives and sub- 3 Force main The effluent transfer system onshore �- pipeline is built with 96-inch inside- diameter reinforced-concrete cylinder pipe.Although the force main has a pumping station, it operates with both pressure and gravity flows.The pipeline can operate by gravity at flows up to 40 mgd at high tide and 70 mgd at low tide.The onshore force main runs 12 miles from the Renton plant to Duwamish Head on Puget ee Sound's Elliott Bay in the City of Seat- ro". tle.The alignment roughly parallels . the Duwamish River and passes through the cities of Renton,Tukwila and Seattle as well as unincorporated " portions of King County. Metro's design consultant,the URS Corp.,prepared specifications for the force main pipe.Metro purchased and supplied the pipe to the installation contractors.There were 3,340 pieces with an average length of 19 feet and an average weight of 33 tons. reinforced-concrete This section of 96-Inch-diameter reinforcedoncrete cylinder pipe is part of the piece was numbered individually for t 2-mile effluent transfer system's force main. identification. Metro used a sophisti- cated scheduling and tracking program to assure chase order for the pipe in April at a cost of$18.3 mil- fabrication and delivery of each piece of pipe as re- lion.The final piece was received and installed on quired by the needs of each contractor. This program March 9, 1986.The 96-inch-diameter force main pipe provided for shop- drawing submittal and approval was manufactured in Lacey,Wash.,by Ameron at a and individual pipe production and fabrication, plant the company developed for this project. delivery and field-location tracking by piece number and installation contractor.Metro placed the pur- Installation of the onshore force main was segmented _ into nine construction contracts.The pipe was in- stalled using a variety of construction methods—from 5 5 traditional open cut to those required for soft-face tunneling,hard-face tunneling and mixed-face tun- WEST- _ = EP. E, neling.There were two river crossings,six jacked tun- _ SEATTLE _ nels and four bored tunnels.The contracts for on- shore construction ranged in value from$1.4 million ' o to$19.5 million.The first onshore construction con- tract was let in August 1985. Final engineering on the N last contract was completed in February1986,and the _ final construction contract was let in March 1986. During peak construction, eight onshore force mains Pipeline ® , RENTON were under construction simultaneously.The total of AP, TREATMENT - . -PLANT all onshore force main construction,including pipe Qlignmenx= \ procurement engineering and Metro engineering and 9UR EN ® management,was about$96 million. 4 Planning the ETS outfall Before building the ETS marine outfall,considerable tent,a shallow outfall. These scientists and engineers study was necessary to determine where it should be considered the depth the effluent plume would be built. Many questions needed to be answered,includ- below the surface of Puget Sound and where that ing: What was the best orientation off Duwamish plume would disperse with regard to biologically Head?How deep should the diffuser be?And how sensitive areas.The scientists' and engineers' prin- long should it be? An intensive siting study was un- cipal goal was to determine the best place to locate dertaken to help answer these and other questions. the outfall from a long-term water quality perspec- tive. Oceanographic and biological scientists and experts in outfall and diffuser design reviewed the options Identification of the approximate area for siting the for depth, the relative merits of a conventional outfall outfall was based on data known during the initial depth versus a very deep outfall and even to some ex- design and study phase.This initial known data in- z t z e. { Y fii �4 1�1 RI F a R, Deep-water offshore geotechnicaI borings were made in the bottom of Puget Sound. 5 eluded tidal flows,bathymetry and other oceanographic information off Duwamish Head.At that time,it was determined that an outfall deeper than any ever previously built would be required. Once the general siting area was identified,addition- al exploration and studies were conducted to confirm and refine earlier discussions. Current meters, drogues,drift cards and other oceanographic survey devices were deployed.Underwater photography WEST POINT N was taken and deep-water offshore geotechnical borings were made of the bottom of Puget Sound. All the data from these studies was collected and analyzed to determine,among other things,saltwater ' SEATTLE density profiles,deep and shallow current patterns ° L.WEAKER and the bathymetry out to 12,000 feet offshore. This :, a,a, j 111RENT5 0VELLIOTT300" and other data were then used to analyze the con- _-1 aA ' I STRONGER structibility of the outfall in the site area.Given the CURRENTS 300'�EGO►. 1` ,'J extraordinary depth,it was important to determine that the project was constructible,what construction ; technologies were available and what alternative ALKI POINT 00 HEAD" techniques could be used to install the pipeline. It w was also necessary to locate the flattest contour avail- able onto which the outfall could be placed.Having considered all of this information and analyses,the outfall was finally sized,configured and aligned. Final design was begun for two 64-inch diameter pipelines,each having a 500-foot-long diffuser sec- POINT WILLIAMS tion.The outfall would project 9,500 feet off Duwamish Head to a depth of 600 feet. This length Currents carrying the effluent. and depth were necessary to discharge into current strata that would provide the best conditions for dilu- tion and dispersion of the effluent. i ca F 0 r 200 EFFLUENT PARTICLES DEEP LL 2 a � SITE 10%' i 300 2 a A00 ° E 10% o 500 ro 2 • O 600 DISTANCE FROM SHORE —.!, VERY DEEPSITE The merits of deep and very deep outfalls were considered. I i I WEST POINT WEST POINTS t J • O } SEATTLE ',SEATTLE It lei BAINBlowe % BAINBRIDGE \ ISLPND •• •. fLLIOTAY 61.41410 EL L 10 TT \� • r to • \ { . a � I ' y nj DUWAMISH Q. ALKI POINT HEAD ALKI POINT HEAD as W dement column n samq slanons • ►A,oh,salmom rr Water ounphi g slats;mmc,StdtiDllS � Beach samPlbg stations ' ® —�Juven le salmnnitlt AA`` Outfall pipes POINT WILLIAMS POINT nILLIgMS ` Water quality data analyzed before Salmonid migration patterns. siting of the outfall. i Design teams were established to use all the data at about the 60-percent level and once at the 90-per- gathered and contribute to the final design.The team cent level. consisted of Metro staff,design-engineering consult- ants and value-engineering consultants. Among the While the outfall design was under way,serious in- issues considered were right-of-way,permits,budget, depth analysis was made of all time constraints and schedule, oceanography,marine biology,water sequencing requirements so that a realistic attainable quality,diffuser design, geotechnical design,strut- schedule could be developed.To complete the outfall tural design,metallurgical design and corrosion on time,Metro determined that some risks would design. Before the outfall design was completed, have to be taken--prudent,calculated risks but risks Metro had valued engineered the outfall twice, once nonetheless. 'r I I i 7 Production of outfall materials 41 The 66-Inch outfall pipe Is the world's largest-dlameter Outfall pipe segments ready for towing to lay barge. mill-rolled pipe. Among the risks Metro took was the decision for ness. It was manufactured by Kawasaki Steel at its Metro to procure the outfall pipe and supply it to the Chiba mill near Tokyo. The pipe was manufactured installation contractor. Additionally,the diffuser in 60-foot triple-random lengths.That is,it had an would be designed and procured separately for sup- average length of 60 feet,a minimum length of 58 ply to the outfall construction. Other long lead-time feet and a maximum length of 62 feet. This pipe was specialty items were also procured by Metro for sup- the largest-diameter mill-rolled,longitudinally ply to the installation contractor. welded steel pipe ever produced in the world. To complete the outfall project in the scheduled time The outfall pipe was delivered to the United States allowed,Metro placed the outfall pipe procurement and unloaded at a Port of Seattle facility on two order in the fall of 1985 with C. Itoh for$3.14 million. ships. It was then trucked to the Lockheed Shipyard Metro specified that the pipe be delivered in early where it was sandblasted lightly. A 40-mil 1986. The pipe ordered was 64 inches outside polyurethane abrasion-resistant coating was sprayed diameter API,5LX60 steel with a 3/4-inch wall thick- over the 20-mil fusion-bonded epoxy,corrosion- IN �A k tt i n Outfall and diffuser pipe sections were welded into 500-to 520-foot segments at Seattle's Lockheed Shipyard. 8 protection coating that had been applied at the mill inch wall thickness. Each had flinch-diameter ports in Japan. In addition to the external coating,the pipe located 3 feet on center. Each port had to have a 15- was coated internally with 20 mils of polyurethane inch-long copper nickel diffusion nozzle welded to it. material for corrosion protection. This required the use of sophisticated procedures to weld copper nickel alloy to high-tensile-strength car- After the pipe was coated,it was taken to a fabrica- bon steel pipe. The end of each diffuser sits on a large tion and assembly area where three sections were sled to provide bearing area. Each sled is 90 feet long, welded together.Three of these three-pipe sections 20 feet wide and fabricated of 30-inch-diameter pipe. were then moved to a launching way and joined The sleds and the diffuser are coated with a together into one continuous nine-piece section.This polyurethane corrosion and abrasion protection 520-foot unit then had a high-strength weld-neck material. swivel flange welded to each end.Once a complete 520-foot pipe section was welded, end plates or blind To manufacture the diffuser's sweep radius ports, flanges were bolted on each end to allow it to float. some unique and innovative techniques were The unit was then launched into Puget Sound. The developed and used. First,2-inch holes were cut launch way had a series of rubber tire rollers laid out where each diffuser nozzle was to be installed. A on a ramp inclined 3 degrees.A hold-back winch was hydraulic die tool specially adapted for this applica- attached to the end of the pipe. Tugs were used to tion was used to up-set the 2-inch holes into flinch, I ow each completed section to storage alongside the smooth radius outlets. Lockheed facility where they were rafted together ke a log boom. During peak fabrication activity, one A counterbalanced flap gate was fitted into the end section was launched a day of each diffuser.These gates will open under exces- sive hydraulic pressure from within the pipe if the The order to fabricate and supply the diffuser was diffuser ports are blocked. In addition, each gate can placed with the Fisherman's Boat Works of Everett, be opened by cable. All flows can be diverted to one Wash.,in the late fall of 1985 at a value of$1.06 mil- pipe by valves at the shore to provide a hydraulic lion. Delivery was specified for spring 1986. Two 500- flush if sediments or other build-up develops in foot-long diffusers were fabricated of A572 Grade 60 either of the outfall pipes. rolled steel with a 64-inch outside diameter and 3/4- .......... m.d S 4'. e Pipe sections were coated with a fusion-bonded epoxy corrosion-protective coating and polyurethane abrasion-resistant coating. 9 Outfall construction In September 1985,Metro called for construction bids placed in an excavated trench and buried up to the to install the outfall pipe. A joint venture of Kiewit point where the depth of water is 120 feet deep at Pacific Co. and Global Consultants/Construction Inc. mean lower low water,or about 2,000 feet offshore. tendered a low bid of$10.16 million against nine To accomplish this,sheet piling was driven and in- other bidders.The engineer's estimate was$19 mil- stalled out to a water depth of 25 feet,about 900 feet lion. Kiewit/Global was given notice to proceed in offshore.The remaining portion was an open trench December 1985.The installation contract specifiea- with 3:1 side slopes. Once the piling was in place and tions required that the outfall contractor design the the trench excavated to the proper depth,520-foot method of installation The contractor was to meet outfall pipe sections were towed by tug to a derrick specified minimum criteria for allowable stress barge that was used to lower the sections into place. limits,cathodic protection assurance,locations,depth To minimize damage to fish life,a seining operation ! t �y�4a A sheet-pile-supported trench Is used to install pipe segments near shore. and other items. Metro's designers,URS,originally was carried out between the sheet piling to herd fish perceived use of a traditional"stove'piping method out of the trench before placing the pipe and backfill- of onshore fabrication followed by an offshore pull- ing. ing,a method similar to one used in the oil and gas industry. Kiewit/Global,however,analyzed working- The deep-water installation was the most innovative area constraints,labor-saving potentials, environmen- and interesting part of the outfall project.As re- tal considerations,permit requirements and alterna- quired,completed 520-foot sections of outfall pipe Live ways to install the outfall.Kiewit/Global sug- were towed by tug from the Lockheed Shipyard and gested that a segmented,offshore-installation brought alongside a lay barge named the Davy method be used. This method would enable a greater Crockett. Kiewit Pacific had converted the World majority of the project to be worked offshore with lit- War 11 liberty ship into an offshore work barge. tle onshore impact to the environment and public. After careful evaluation of the engineering and Each 520-foot outfall section brought alongside the analysis of this installation method,Metro and Davy Crockett was placed into harnesses that were Kiewit/Global refined the proposal,which resulted slung off fall lines rigged 100-foot from the fore and in a very satisfactory installation solution.The aft ends of the barge.Once supported in the har- agreed-upon method involved using a flanged-end, nesses,the inboard pipe end (closest to shore) was bolted-up,segmented procedure. rigged with an alignment frame and a bolt-up tool. . The outboard end was rigged with four air bags, The outfall installation project had two distinct opera- each fully inflated to provide 20,000 pounds of lift. tions: the near-shore installation and the deep-water When this rigging was completed,the blind flanges installation. In the near shore,the outfall pipe was were removed from each end of the 520-foot pipe sec- 10 tion.The pipe section was then lowered carefully to Each torque wrench was calibrated on-board the lay meet a previously installed 520-foot pipe section that barge before and after each bolt-up to ensure full had its end raised above the floor surface of Puget compliance with bolt stress requirements. Sound by air bags. During actual underwater installation,the on-board Kiewit/Global had designed and manufactured a control room operator was in constant contact with a full remote-controlled or robotic bolt-up tool especial- three-person submarine used to observe the bolting ly for this project. This tool was fully capable of align- operation.The operator of the sub maintained radio ing and making up each of the bolts on the flanges contact with the control room operator and used TV by remote control at all outfall depths.The bolt-up cameras to observe the bolting-up operation constant- ,l KlewlVGlobal used a converted World War II liberty ship,the Inflatable air bags at the and of each pipe eased Installation of Davy Crockett,to Install the outfall pipe segments. pipe sections above the floor of Puget Sound. tool consisted of two hydraulic torque wrenches and ly.This submarine monitoring supplemented the TV three TV cameras mounted on a rotating frame. The camera on the bolt-up tool used to monitor each im- bolt-up tool was fully controlled through hydraulic act wrench. lines by an operator in the control room of the Davy p Crockett,using the TV cameras to view and monitor When necessary,divers were available to assist the progress• remote-controlled flange make-up.The Davy Crock- ett was fully equipped to provide traditional"hard The torque wrenches on the bolt-up tool were spaced hat"as well as saturation diving. A diving bell and at 180 degrees and rotated during bolt-up to make up pressure chamber were on board for saturation the 60, 1-3/4-inch-diameter bolts.The bolts were diving. The pressure chamber could have been the made up in a rotating sequence in the same manner habitat for two saturation divers for up to two weeks as the head gasket on an automobile engine is at a time.Saturation divers were"jump dived"on f tightened to minimize distortion. two occasions. A minimum torque was required to produce a 50-per- To ensure full compliance with the installation stress cent bolt-tension yield. At 50-percent tension in bolt, restriction on the pipeline, the stresses of the outfall the flange develops the full bending capacity of the pipeline were analyzed as the outfall pipe was in- pipe section. The maximum torque allowed stalled. A job-site computer was used in conjunction produced 80 percent of tension yield or 60,000 psi in with a specially adapted,finite-element,dynamic- the bolts. A maximum torque was established be- stress program. This program analyzed the pipe as a cause,at higher stresses,the bolts in the salt water beam on an elastic foundation with deflections super- risk stress cracking and accelerated corrosion. 11 imposed. Input readings of the program were the in- profile drawing with the as-installed stresses indi- place gradient or sounding of each pipe section as cated for each 20 feet.The highest stress ever en- measured physically from on board the Davy Crock- countered in the pipeline was 83 percent of the ett. The data were fed into the stress analysis formula specified minimum yield.The allowable stress was and a stress calculated for every 20 feet of pipe. A 90 percent printout of this data was prepared as was an as-built f �.bb``AR -wAat. At e r l ` Y 11, The alignment frame and bolt-up tool,mounted on a pipe segment,are prepared for installation- 12 Risks In addition to the risks mentioned earlier,other controlled bolt-up tool underwater could have had phases of the project were planned,implemented serious effects on pipeline alignment and make up. and completed with knowledge of their possible ad- This procedure required careful attention to prevent verse effects on the environment and construction failure of the pipeline flange joints after installation. progress.In one case,a portion of the nearshore pipeline was suspended in the water after a landslide Metro also took steps to reduce or prevent inter- occured beneath it.Contractors built a bridge of rock ference with ferry service,commericial navigation to support the pipeline and stabilize the pipeline and salmon migration. Metro negotiated construction trench in the landslide area. schedule agreements with the Coast Guard,an In- dian tribe and the state departments of Ecology and Other risks taken included the towing of outfall pipe Fisheries. To protect spring-time salmon runs,the en- I sections into Puget Sound and then lowering them tire effluent transfer system project was scheduled to into place. Pipe sections, having been welded be completed before low-flow periods in the together onshore,could have failed physically during Duwamish River. these maneuvers. In addition,failure of the remote- I f i I I I I �I 13 Conclusion Completed under budget in less that three years,the effluent transfer system began operating as planned in March 1987.Removal of the Renton plant's secondary treated effluent from the Duwamish eliminated the threat of ammonia and chlorine toxicity,increased dissolved oxygen levels and lowered the water temperature—all immediate improvements to the river.While data collected so far are not enough to indicate a trend,concentrations of ammonia and phosphorus in April 1986 were as much as 10 times the levels detected in April 1987—one month after total effluent removal. If there is a message in the success of this one-of-a-kind record-of-firsts leading-edge-technology outfall project,it is that the engineer,the owner and the contractor must throw their full resources at a project and not get stifled by self-protectionism,undue conservatism and their traditional individual roles. Rather,they should be creative and far-reaching,work together with open minds and dialogue and keep the successful completion of the project as the focus. In short,don't be afraid to join hands and take prudent calculated risks. To achieve success as a team,build a program to manage the project and risks collectively. This project could not have been the success it was if Metro,its owner, URS Corp.,the designer,and Kiewit/Global,the contractor,were each not willing to support these principles. i i I I E ' 14 —"'TGTRO Fr 2'AHh Ssa�vrr»w�t�b oh�? Municipality of Metropolitan Seattle Exchange Building • 821 Second Ave. • Seattle, WA 98104-1598 January 19, 1995 Mr . Clinton Morgan Engineering Specialist Development Services Division City of Renton 200 Mill Avenue South W/M8-95 Renton, Washington 98055 10-09 .01/2 Subject : P-1 Channel Trail Dear Mr. Morgan : Thank you for your comments on the construction plans of the subject project . In accordance with your comments, we are submitting a set of revised black line drawings for your final approval . Upon approval of this set of drawings we will submit mylar originals to Public Works for authorized signatures . We do not anticipate any street closures during execution of the construction contract however, if the need arises we will comply by submitting a traffic control plan to the City for approval. We are also transmitting a detailed project cost estimate for your perusal . After my previous discussion with you it is my understanding that the City does not require a security device; this will be accomplished through our contract documents . During project planning it was agreed to, with the Director of Parks Department to provide a 10-foot wide bicycle/pedestrian trail rather than the usual 6-foot trail and that no landscaping would be provided. If I can answer any further questions please call me at 684-2423 . Very truly yours, Joe Fernandes, Manager Treatment Plant Enlargement in Renton JF:em CITY OF RENTON MEMORANDUM DATE: December 21, 1994 TO: Clinton Morgan FROM: Ron Straka STAFF CONTACT: Scott Woodbury SUBJECT: Metro P-1 Channel Trail SW Grady Way to Oakesdale Avenue SW Following are Surface Water Utility review comments on the above-referenced project drawings as requested in your December 19, 1994 memo: 1. Perforated piping subgrade drainage. We are concerned about the potential effect that the perforated piping subgrade drainage will have on the existing vegetation on the channel side of the proposed trail. In 1990 the City of Renton, with the assistance of the Natural Resources Concervation Service (NRCS), planted the banks of the P-1 channel along the length of the proposed trail. With a limited water supply and difficult soil conditions, these plantings have struggled to survive. The proposed perforated piping system will further reduce the water available for plant survival and should be mitigated. Intermittent watering during the dry season using an automatic system or portable supply would be acceptable. 2. Landscaping. Any plants previously planted as part of the NCRS and City habitat enhancement projects that are disturbed by the proposed construction must be replaced in kind or with an approved substitute from the attached plant list. 3. Outfall protection. All new outfalls must have rip rap slope protection per the attached revised detail 112. This includes any subgrade drainage outfalls. Because the portions of the banks of the P-1 channel were rip rapped when the channel was constructed in 1987, the new outfall rip rap only need extend to match with the existing rip rap and may not have to be extended past the slope toe as shown in the revised detail. Based on the revised detail, the plan view drawings of the proposed outfall slope protection must be revised accordingly. 4. Outfall construction. Any work within the ordinary high water mark of the channel must be in accordance with an approved Washington State Department of Fish and Wildlife Hydraulic Project Approval Permit. R Clinton Morgan P-1 Channel Trail Page 2 5. Property and easement boundaries. The proposed outfalls shall be treated as a private storm system connection to a public storm system. The maintenance of the private storm system up to the point of connection (outfall discharge point), including any outfall slope protection, shall be the responsibility of Metro. 6. Miscellaneous. The clearance at the Oakesdale Avenue SW bridge is dimensioned to be 8.7' while the profile drawing (sheet 4 of 9) shows only about 4'. It is assumed there just was not enough space on the drawing to show the bridge at the correct location on the profile drawing. Thank you for coordinating comments on the Metro project. If you have any questions regarding the above comments, please call Scott Woodbury at X-5547. H:DOCS:94-1164!:SW cc: Neil Watts attachments UC lt'f/Lo�0g; RIP RAP !" lAssODf {°Il% / sGG{f.- 11-r3,1 �cL�Sp 1W C-t-, 64AAt ASPHALT CONCRETE PAVEMENT, CLASS B a, INSTALL TRASH RACK ON ALL 30' DIAM. PIPE- e SEE STD. PLAN 8046 AND 8048 CRUSHED SURFACING BASE COURSE 2:1 BEVEL \ ri 30' RCP � GtGNf r C�/m�lr�pp- v, r RIP-RAP f 1 viSDo`� T9gl q� T;.,.i 9A3.� _ . •�a '. �mOe HEEDED WIRE FABRIC Ip 18' RCP •$ • CONCRETE, CLASS 3000 �k�Eh r 1 PIPE BEDDING 12' MIN. �`- UNOISNRBED SOIL - LIMITS OF RIP-RAP - p TYP• RIP—RAP SLOPE PROTECTION _CONCRETE PIPE SADDLE STA. 15+87 STA. Z STA 27+52 NOT TOO SCALE CALE NOT TO SCALE GENERAL NOTES 1. THE P-1 CHANNEL TRIAL CONTRACTOR SHALL COORDINATE WITH THE WATERWORKS CONTRACTOR FOR PLACEMENT AND/OR CONNECTION OF r it THE PROPOSED (ie OR 30-) PIPE AS SHOWN ON PLANS. r CONNECT TO MANHOLES AND/OR PIPE SEGMENTS IF ALREADY IN Ic PLACE AND VERIFY INVERT ELEVATIONS AND LOCATION PRIOR TO CONSTRUCTION. IF WORK BY OTHERS IS NOT IN PLACE. INSTALL NEW TIIRFSTONE o o TURFSTONE o o (18- OR 30-) PIPE AND COVER PIPE ENDS WITH PLYWOOD. TURFSTONE MARK PIPE ENDS WITH 4'X4' WOOD POSTS AT IS' ABOVE GROUND. iv SUBMIT ON METHOD OF CLOSURE AT ANY CLOSURE JOINTS. N N N N N 2. THE P-1 CHANNEL TRAIL CONTRACTOR SHALL CONSTRUCT THE PROPOSED WALKWAY UP TO THE METRO PROPERTY LINE ALONG THE SAID ALIGNMENT. 30' J150 30, IF THE 18' OVERFLOW PIPE HAS NOT YET BEEN INSTALLED, BY THE WATERWORKS CONTRACTOR, THEN THE PROPOSED WALKWAY SHALL BE CONSTRUCTED UP TO A POINT WHERE IT WILL NOT INTERFERE WITH THE EXCAVATION REQUIRED FOR THE INSTALLATION OF THE 18' OVERFLOW PIPE. THE P-1 CHANNEL TRAIL CONTRACTOR SHALL COORDINATE WITH THE TYPICAL PLACEMENT OF TURFSTONE OFTTHE WALKWAY.CONTRACTOR CONCERNING THE CONSTRUCTION AND COMPLETION STA 14+80 TO STA 19+90 TRAIL SCALE 1'=10' 3. FILTER FABRIC FENCES SHALL BE INSPECTED IMMEDIATELY AFTER EACH RAINFALL AND AT LEAST DAILY DURING PROLONGED RAINFALL ANY REQUIRED REPAIRS SHALL BE DONE IMMEDIATELY. FILTER FABRIC FENCES SHALL BE. REMOVED WHEN THEY SERVED THEIR USEFUL PURPOSE, BUT NOT BEFORE THE UPSLOPE AREA HAS BEEN PERMANENTLY STABILIZED. REMOVAL OF THE FILTER FABRIC FENCE NEAR THE PROPOSED 18- OVERFLOW PIPE SHALL BE COORDINATED - - WITH THE WATERWORKS CONTRACTOR: 9 B q � R g_ i a,IAI/ CITY OF RENTON D6PAATH OF PV IUC IIOR ,N METRO P-1 CHANNEL TRAIL SECTIONS, DETAILS do NOTES S CALL 2 DAYS BEFORE YOU DIG — 1-800-424-5555 . „g, , �Dswr sr .ww own iw.aovm� QUAN. PLANT KEY SCIENTIFIC NAME COMMON NAME SIZE REMARKS SO4 A I -O C SI PH _AumMaimin I SHRUBS ` -AF A"WkwKlw Ronda Podf S 40L.3-4'Ifr. cwftkw i 2M M mc 2d id Pnsws aIw _ tsc.'Nr wr cPJVw 100 ro -- - Sallcottan IT ,Hilo. i PLANT LI ST I �a II i se BB I B A!r'RO+m Tsrc rtFs -..ar�:...m i<rt B - see secs) Tes :Yc erxs) N�IE s�.riE sr^�cc u,'S w.R..ar TlV>= STacL _ _�•_o_ o_ . . 'A', J 5 PL?A!r o. - „ •ig HAKDWC00 CrlTrtNy �XAM� MIX _ �r _ T�Pe.4:_� cE-n_,re�r PLAWT 116T F PLANTIFIG oe II..S WIt_DUc6 HABITAT PLANTW4 PtA►J ^ni NQru t:a¢S-� CF+9tiT ft v.rT1NG HIl( ZtA,eT SIDC 61RL•EN RIvs A, P-+cM.wNa�. T�ACvLNr seT1tET£rrr FIT %•ark VMaCS U. �. UF:1':1 N'f\i F.`.'I' I �i- :'v J;H l I:II I:: pecIyuous YxEs-csurxw w L�iA&KEIMA TKFE-ccurAwEn `f 0IL CONSI',R1 :\I PIN >IU:\ If I PLA NTI N C D� �I l_ a „aa T.99. � S e� 17 ESSR-11 DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS DEVELOPMENT APPLICATION REVIEW SHEET APPLICATION NO: LUA-92-127-SM PROPONENT: Metro PROJECT TITLE: Metro Wastewater Treatment Plant Stormwater Outfalls BRIEF DESCRIPTION OF PROJECT: Shoreline substantial development permit for construction of three outfalls to the P-1 Channel: an 18" discharge pipe from the stormwater system and two 30" overflow outfalls. The stormwater system will be constructed during the current expansion of the regional wastewater treatment plant. Approximately 6 of the 86 acres which make up the site are within the shoreline district, adjacent to the P-1 Channel. LOCATION: SEC: 24 TWNSHP: 23N RNG: 4E 1200 Monster Rd SW TO: PROJECT MANAGER: Paul Forsander(6167) PUBLIC WORKS DIVISION SCHEDULED TAC DATE: 09/15/92 ENGINEERING SECTION TRAFFIC ENGINEERING SECTION UTILITIES ENGINEERING SECTION FIRE PREVENTION BUREAU POLICE DEPARTMENT DEVELOPMENT SERVICES DIVISION CONSTRUCTION FIELD SERVICES DEVELOPMENT PLANNING PGA N OTHERS: COMMENTS OR SUGGESTIONS REGARDING THIS APPLICATION SHOULD BE PROVIDED IN WRITING. PLEASE PROVIDE COMMENTS TO THE DEVELOPMENT PLANNING SECTION BY 5:00 PM ON SEPTEMBER 8, 1992. d.ht trey.lee REVIEWING DEPARTMENT/DIVISION: R►�'� APPROVED APPROVED WITH CONDITIONS NOT APPROVED 4!/i6'rtl A vo l��ro✓�%/f Cl- � /N�AIi `J1D} s�Ll/Y /LlA/lA�erf-'4lluk ��lv /1,r>v P45.5n ,gyp yt . 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INCLUDES: .CENNECTION TO ABANDONED /- µp(1.tKEsN CONVEY— WATER ¢Omro1T WEaS PWJNING ZpN I •CONNECTION TO WiLUENT SEWER DIVISION ua a o YY MTPRxTREAT- CITY OF RENTON o a j �4& j AUG 0 4 1992 6� JAIL GAIUM NOTE m i"M E T R O M•---•���N, Of �wP°Btm S°°Kk 6/16/92 Tp,,�mars L. WUER /r BC Brown and Caldwell METRO'S REGIONAL TREATMENT PLANT IN RENTON nu x¢ iariA n CAD TEAM GRN SITE PLAN Consultants `�xa Je ND SCAE Wx Je e pia xn Seattle, Washington EMERGENCY RELIEF OVERFLOW xo mWRw 6r P.1E AND WET POND EFFLUENT PIPE ¢Tx¢ ," 2 j l I .I- ,w n,wa n,au --- Iz m rwm) ,w w[r rwo vswe+T sl � ( �I' III,•. I I oo. II j l I \ „o `------n d--— 5 JTH o�aow C,-, ti v nmol v ,w NtoN sy A(6 0 AN 4 a . . H ` 2£ HoRDi owmnw Vli L METRO Brown and Caldwell ax— ""`""" uo rt w BCf1 sCons alt�ag�ts EMERGENCY RELIEF OVERFLOW 2 AND WET POND EFFLUENT PIPE z I SHORELINE MANAGEMENT PERMIT APPLICATION P R O J E C T S U M M A R Y Metro will be constructing three outfalls to the P-1 Channel as part of the stormwater retention system for the treatment plant located at 1200 Monster Road S.W. One will be an 18 inch discharge pipe and the other two will be 30 inch overflow pipes which will allow stormwater to bypass the system during major storm events. All pipes will be installed using an open trench method except for the area adjacent to the P-1 Channel. The construction method in that area will be by clam-shell dredge so that the trench can be sheeted. The pipes will be encased in concrete as they emerge from the bank. Riprap will be placed from the pipe invert to the creek bottom to dissipate the hydraulic energy and reduce erosion. The construction will take place in the summer of 1995. G:GJR3SWM1 "ur1 Nts�N oORE,'TSON � 1 g 1992 PROJECT DESCRIPTION FOR STORNWATER OUTFALL AND TWO 30 INCH DIAMETER EMERGENCY RELIEF OVERFLOW OUTFALLS INTO THE P-1 CHANNEL The existing Metro treatment facilities in Renton are being retained and upgraded to optimize their capacity. New facilities are being added to further increase treatment capacity. The existing plant has the capacity to provide secondary treatment for 72 million gallons of sewage a day (mgd) . The expansion from 72 to 108 mgd, is referred to as Enlargement III. Phase A of Enlargement III entails site preparation and perimeter landscaping. Phase B is the liquid and solids stream upgrade and expansion. Phase C includes final landscaping and cleanup. New impermeable areas to be constructed in Enlargement III include paved areas for access roads, parking, and a maintenance foot-trail, open channels, tanks and process structures . Most roadways and parking areas will drain to the existing underground storm sewer system which discharges to the Green River. Parking areas used to unload septage, load dewatered sludge and load grit will drain stormwater runoff to the plant's sanitary drain system. The sanitary drain system is routed through the plant for treatment and is ultimately pumped to Puget Sound through a 108-inch diameter force main - the effluent transfer system (ETS) . Rainwater falling into open channels and tanks, onto covered channels and tanks, and onto process structures will be routed through the wastewater' treatment plant. A stormwater pump station will be constructed at the confluence of the underground stormwater sewer system to lift stormwater to a wetpond facility located on the surface. The capacity of the wetpond facility and pump station will be three times that required by the King County Surface Water Design Manual (SWM) for wetponds. The wetpond facility will be oversized to compensate for new impervious areas which will not receive treatment via biofiltration swales. Metro anticipates that the oversized wetpond facility will attain pollutant removals equal to or greater than removals attainable with a wetpond facility sized according to minimum requirements in series with the required biofiltration swales. Treated stormwater will drain from the wetponds to the P-1 channel. Two new 30-inch emergency relief overflow sewers, which will also 'drain to the P-1 channel , will provide flood protection and stormwater treatment bypass during extreme flood conditions in the Green River. The wetpond facilities, associated outfall piping and the emergency relief sewers are scheduled for design and construction during Construction Phase C. Until the time when the oversized wetpond facilities are in operation, stormwater will be pumped to the wastewater treatment plant for treatment and 0,jfk@kdpxqsolto Puget Sound. cTTY OF RENTON AUG 0 4 1992 1 Stormwater Pump Station The existing underground stormwater sewer system will be augmented with a stormwater pump system at the storm sewer junction manhole. The pump station is necessary to lift stormwater flows requiring treatment from the underground storm sewer to water quality facilities located on the surface. This pump station will have the capacity to pump three times the required design storm peak flow rate for wetponds, i.e. , 4 . 5 cfs (2 .9 MGD) . Flows in excess of the pump capacity will bypass the pump station and drain to the Green River via the existing 120- inch outfall diffuser. The proposed system will retain the flap gates located at the outfall manhole to prevent the influx of the Green River into the stormwater sewer system during extreme flood stage in the Green River. Emergency Relief Sewers Two new 30-inch emergency relief overflow sewers, one to serve each of the two stormwater sewer branches, are proposed for the underground stormwater sewer system. Stormwater entering these overflow sewers will discharge to the P-1 Channel . These overflow sewers will provide relief to the plant's stormwater sewer system during extreme flood stage in the Green River, and allow flows to bypass the stormwater water quality facilities as required by the SWM. The relief sewers take advantage of the elevation difference between the Green River and P-1 channel during extreme flood events, i.e. , Elevation 121 and Elevation 114, respectively, during the 100-year flood event. Emergency overflow weirs will be set at Elevation 118. 0 and be located near the eastern end of the 30-inch pipe branches. Stormwater flowing over the weirs will flow by gravity to ,the P-1 Channel through 30-inch pipes. Both emergency relief sewers will be supplied with a flap gate to prohibit water in the P-1 channel from entering the on-site stormwater system. The emergency relief overflow sewer plan will satisfy the goals of the Green River Management Group. The Green River Management Group manages the Green River Drainage Basin and controls the influx of flows to the Green River. For example, the Black River Pumping Station must start to throttle pumping when the Green River reaches 9000 cfs and must stop once the flow in the Green River reaches 12000 cfs, i.e. , about the 100-year flood stage. Overflowing the treatment plant's storm sewer system to the P-1 Channel allows the Black River pumping station to regulate the discharge of stormwater to the Green River, a preference of the Green River Management Group. 2 Shoreline Jurisdiction The P-1 Channel north of Grady Way is a "shoreline of the State" and is under the jurisdiction of the City of Renton's Shoreline Master Program. The City has designated this shoreline as being in the "urban" shoreline environment. The portion "Of the project that involves construction within the 200-foot shoreline jurisdictional boundary includes parts of the two 30-inch emergency relief overflow pipes which serve each of the two stormwater sewer branches and discharge to the P-1 Channel and the single 18-inch pipe which will discharge treated stormwater from the wetpond facility (see Figure 1) . Installation of these pipes will occur during Construction Phase C of the treatment plant expansion which is scheduled for 1995. This work will be scheduled for the period of June 1st through September 15th, 1995. P-1 Channel The P-1 Channel was constructed in 1984 to convey drainage from the Southcenter area and local drainage north of I-405 into the former Black River channel and ultimately into the Green River. The channel generally follows the former path of Springbrook Creek and thus is referred to as both P-1 Channel and Springbrook Creek. Drainage is impounded in the P-1 Pond and pumped into the Black River channel before discharge to the Green River. The P-1 Channel joins the former Black River south of a forested (cottonwood) wetland area, at the P-1 Pond behind the county pumping station. The present Black River channel is only a remnant of its former course, but it still flows year-round. The shoreline along the P-1 Channel where the three pipes will daylight several feet above ordinary high water (Elevation 103) consists of a steep dirt bank vegetated with a mixture of native and non-native grasses. Palustrine emergent and scrub-shrub wetland vegetation including cattail, canary reedgrass and willow and alder saplings grow in the saturated soils immediately adjacent to the creek. The vegetation reduces the erosion potential along the banks during high winter flows. .The creek bottom is primarily silt due to the heavy suspended solid load normally carried by the creek. Water Quality Water in the channel generally appears very turbid at the point where it discharges to the Black River. There is no recent water quality data available for the lower channel or the P-1 Pond. The limited data available were obtained in the mid-to-late 19701s, and indicate that turbidity, dissolved oxygen, and total coliform levels exceeded the levels for State Class A waters. Metro sampled water quality in the upper P-1 Channel/Springbrook Creek near the northeast corner of Longacres property. The 3 general water quality was rated as poor and it continues to be among the most degraded streams in Metro's sampling area. Problems include low dissolved oxygen levels, high temperatures, high fecal coliform counts, high turbidity, high total phosphorous and ammonia, and high conductivity. Dissolved oxygen concentrations violated the Department of Ecology criteria in eleven of the twelve samples collected with a median value of 6. 0 mg/L. Fecal coliform counts violated Ecology fecal coliform criteria in seven of the twelve samples collected (geometric mean value of 399 org/100 ml) . The median temperature was 11.8°C (51. 8°F) which was higher than the majority of streams in Metro's sampling area. However, temperature exceeded Ecology criteria only once. It is likely that the low dissolved oxygen levels are in part due to poorly oxygenated groundwater inputs and low gradient flows. In addition, the nonpoint sources of organic loading from the large number of waterfowl inhabiting the area, agriculture, thoroughbred racing, and urban runoff can reduce oxygen levels. Because of its already poor condition, P-1 Channel/Springbrook Creek is susceptible to impacts from deposition of fine sediments. Sediment metal concentrations measured in P-1 Channel/ Springbrook Creek were lower than in previous years, though still a problem, falling near the middle of the range for the streams. Zinc levels exceeded the acute standards on four of the six occasions measured during high flow. The City of Renton Shoreline Master Program (Section 7 . 18 . 02) specifically addresses the installation and operation of pipelines with regard to water quality issues. It is anticipated that the stormwater discharge will not further degrade water quality in the P-1 Channel/Springbrook Creek. It is possible that during construction the turbidity criterium of the State Water Quality Standards will be exceeded but this is only a temporary occurrence and will not cause significant impact to the creek. Pipeline Construction The wetpond effluent pipe (18-inch diameter) will be open cut with a backhoe the entire length because of the relatively shallow depth (9 feet) using 1. 5: 1 slopes. The two 30-inch pipes will be open cut with a backhoe for most of their length. The 100 feet of trench adjacent to the P-1 Channel for each 30-inch pipe will be sheeted; consequently, the 4 .5-foot trench width will be excavated by a clamshell dredge. Excess volumes of dirt from excavating the pipe trench will be used for landscaping on- site. All exposed surfaces will be hydroseeded after the construction is completed. All three pipelines discharge into the P-1 Channel several feet above ordinary high water (Elevation 103) as shown on Figure 2 . 4 The pipe will be encased in concrete as it emerges from the bank. Riprap will be placed from the pipe invert to the creek bottom to dissipate hydraulic energy and reduce erosive forces. The typical method of placement of riprap would be to dump rock from a dump truck into the stream at the location of the emergent pipe. The rock would then be placed by hand in the creek bottom so that the area is smooth. Each pipe will include a 72-inch manhole. The manhole cover will be the only portion of the pipeline visible from the surface other than the pipe energy dissipation structure. Cost of the project is approximately $250, 000 . c:GJR3sw 5 M TR d4s ® Municipality of Metropolitan Seattle Exchange Building • 821 Second Ave. Seattle,WA 98104-I598 (206)684-2100 May 1, 1992 Ms. Lynn Guttmann, Administrator Department of Planning/Building/Public Works City of Renton 200 Mill Avenue South Renton, Washington 98055 Treatment Plant Expansion III Application For Variance To Stormwater Drainage Code Dear Ms. Guttmann: Submitted for your approval are Metro's final Drainage Plan and Request for Modifications for the enlargement of the treatment plant at Renton. Metro has worked closely with Randall Parsons, who is responsible for stormwater management at the City of Renton, to develop this drainage plan and the stormwater management program described therein. At the request of City of Renton staff, Metro has provided additional information on the environmental impacts of the proposed facilities as Appendix B of this application (correspondence from Adolfson Assoc. Inc. ) . Based on this additional information, Metro has concluded that the proposal does not create probable significant adverse impacts beyond the range of alternatives and impacts analyzed in the existing environmental documents (FSEIS for Metro Treatment Plant at Renton: Phase III Enlargement, May 24, 1991) . Per Ordinance 4342 and your stormwater regulations Metro requests your approval of the enclosed drainage plan and stormwater management program submitted. Sincerely, n / Gregory M. Bush., Manager P Environmental Compliance on}oPofv� and Right of Way and Property Division A RfirypOroM GMB:gj e 04 ,992 vkb :.i L.='7RN-+:.�... Y '•s� 1.5.:2'., !D: - 3 R.W. BECK AND ASSOCIATES Fwni.u.dHhncincd Fuillio,.buim 600■2101 F..wu A+.o.. Sacd..tF.+6inrma 96323.2375 i LU T,1,phme(206)},1.7700 A Fu(206)41)-49dr T.1..49w4or 9ECKSEA WW-1421-AA1-AA January 22, 1992 3�3 Mr: Randall Parsons, Utility 3upe_rvisar Storm Water/Waste Water Utility Systems Division City of Renton 2w Mill Avenue South Renton, WA 98055 Dear Randall: Subject- MM0 Trearment yLmt Expansion Prujcct Review or Storm Water Dlveniuu AL the Metro TMUnerrL Plant in$snioa We arc pleased to submit the results of the Task 1 work for the subject project. The analysis was perfurmed by NarthwestHydraulic Consultants (NEC)and reviewed by our office Copies of their calculations and analysis are attached. The purpose of the work was to estimate krc iucrraso la runoff volume rccrivcd at the B1ackRiver Pump Station(BRPS�forehay resulting from the proposed Macro diversion during an ==mc high Gwen River :now condidor:- The analysis included using dir HSPF' hydrology.developed at a part of the ESGRW Plan. More sper fLcally, the simulation included the local 100-year flood control storage event under current land use conditions in coincidence with high Gran River fnnws. Based on the work by MCI the predicted incrose in forebay elevations would be 0.07 feet(lmpmximatcly 1 inch). This use in elevation eoaespondE to an increase in volume.rrrivtd at the forcbiy of approximately'1.5.ao-ft during a period in which the forehay is filled to approximately elevation 6 (storage 132 ac-ft). We do not.believe that pe�rming the work under_Task 2 would be.beneflrissL= Pec- Fnrmin8 a detailed �ulahon using SSPFIFEQ would more a==tely estimate the elevation in the forebay, however, the relative change In elev2hon and the increase in runoff volume at the forebay from the Metro diversion would be nearly the same as predicted by the ESPF aralysis. MG.vn bwnn,l7A (ilumha,.trE•Om.e+.[D.W6..."16.IN.x)....,..L.•MW N.shvUl TN.orua".FL.n.m AZ.Saw w.CA�`�Wa WA -c .r },na....__.r_•AEY.');ON CONSTB T2AIL7.. 0]-22-92 03: 24?M n'002 =3E LED _s:M Io:PCWvMmrsr ;rZatt. TE- 10: =6) 4s5:-a "r.'-ate HCU' l�•9: ttn CC�t, n w�1H1.`.:. rru, nV. Gu0 Mr. Randall Parsons, Utility supervisor Storm Warer/Waste Wa= 2 January 22, 1992 We would be happy to meet with you to discuss the =v1:1 of the analysis. If you have any questions, please contact our office. Vcry truly y=s, IL. W. BHCK AND ASSOCIAATTF-S h0m Gisebuf[ ' Project Engine' meets Enclosure c: I= Fernaudes, Managm Moro Treatment Plant Expansion nsw.ov R•W.Ha< z=.1:-�:r.hl Ihow 14don P.iNTON GOt:5:2 TP.1.7 I-P. 01-22'0-2 03:24?"• ?003 �36 MTPR Drainage Plan - Drafc March 25. 1992 APPENDIX B (Water Quality Impacts of Redirecting MTPR Stormwater Runoff into the P-1 Channel by Adolphson and Assoc . ) 26 September 24, 1991 2.5 c Ms. Laurie Endlich j METRO ,t 821 Second Avenue Seattle, Washington 98104-1598 RE: Runoff impacts to the P-1 Channel from the Metro Treatment Plant at Renton Dear Ms. Endlich: As requested, I have evaluated the potential impact to water quality in the PA Channel resulting from discharge of stormwater runoff from the Metro Treatment Plant (MTP) at Renton. I have reviewed information including the Drainage Report Metro Treatment Plant at Renton Enlargement III September 16. 199_1_ Draft to City (Brown and Caldwell, 1991); and subsequent revisions of proposed wetponds developed by Brown and Caldwell. I have also reviewed preliminary modeling results by the City of Renton (personal communication, R. Straka, City of Renton, September 23, 1991). Water Quantity Impacts. For this evaluation, I assumed that peak stormflows in the P-1 channel at the point of discharge from the MTP are approximately 90% of the flows at the . forebay of the Black River Pumping Station, where modeling results are available. This I assumption was based upon the estimate (utilized for modeling by the City of Renton) that existing peak storm flows in Springbrook Creek under 1405 are between 82% and 90% of the flows at the Pumping Station Forebay, depending upon the intensity and return frequency of the storm. For existing conditions, estimated peak storm flows in the P-1 Channel for a 2-year 24-hour storm is approximately 604 cfs. Peak discharge from the MTP stormwater system during the 2-ye2r 24-hour storm is 4.5 cis, or approximately 0.7% of peak stormflow in the P-1 Channel. Under future conditions (full buildout under existing adopted comprehensive plans), the peak flow contributed by the MTP will represent approximately 0.6% of peak flow in the P-1 Channel. This increased flow will have minimal impact to peak flows in the P-1 Channel under both existing and future flows. Water Quality Impacts. The proposed wetpond facilities have been designed to provide maximum pollutant removal efficiency, in excess of minimum requirements for wetponds promulgated by King County Surface Water Management Division. Based upon generally- accepted levels of treatment removal for wetponds, upwards of 80% of settleable particulates can reasonably be expected to be removed from influent stormwater entering the wetpond facility. ADOLFSON ASSOCIATES, INC. EnrinmmeWal Anal vsis 600ilfain Slreer Edu:ouds, IE4 98020 r206i 778-4273 F.-LV(206) 771-5053 page 2 of 3 Stormwater from the MTP will drain from rooftop areas and paved roadways and parking areas. Although vehicle traffic on the MTP roadways will be lower than+.a typical public roadway, there will be some deposition of vehicular byproducts, including metals and petroleum products. The site runoff will be treated by routing this runoff through biofiltration swales (33% of proposed new roadways and parking lot areas will be routed through biofiltration swales) and the wetpond facilities. Because most of the metals commonly detected in urban runoff are associated largely with particulates (e.g., lead, copper, and Zinc), these constituents by sedimentation can be significantly reduced by the wetpond facility. Regular maintenance of the facilities will ensure that deposited sediments are not flushed out of the treatment facilities and into the P-1 channel. Other parameters which are typically associated with particulates will be significantly removed by the treatment facilities, including: (to some degree) total and fecal coliform; and total phosphorus. Petroleum products will be removed to an unknown extent, largely by the biofiltration Swale. Currently, water quality in the P-1 Channel is degraded, with low dissolved oxygen levels, high temperatures, high fecal coliform counts, high turbidity, and high total phosphorus and ammonia levels. The peak storm flow contributed by the MTP represents less than. 1% of the total peak storm flow in the P-1 Channel, as described above. The quality of stormwater discharged from the MTP stormwater treatment facilities will likely be higher than receiving water quality for numerous parameters, and is expected to be less turbid. Because the stormwater discharged from the MTP is such a low percentage of total flow in the P-1 Channel and the quality of discharged runoff is-expected to be as high as can be provided using accepted state-of-the-art treatment technology, no discernible impacts to the P-1 Channel are anticipated in the short or long term future. To determine the treatment effectiveness of the facilities, as well as an optimal maintenance schedule, I recommend that stormwater monitoring be conducted at the facilities. I would recommend monitoring influent and effluent stormwater during three or four storms annually foliowing implementation of the facilities. If you have any questions or comments, please contact me at (206) 778-4273. Thank you. Very truly yours Molly v olfson President / ADOLFSON ASSOCIATES, INC. page 3 of 3 cc: Mr. Rick Butler, Brown and Caldwell Mr. Jack Warburton, Brown and Caldwell Mr. Render Denson, Brown and Caldwell CITY OF RENTON MEMORANDUM DATE: April 30, 1992 TO: Gregg Zimmerman FROM: Randall Parsons SUBJECT: METRO TREATMENT PLANT EXPANSION III REQUEST FOR STORM DRAINAGE CODE MODIFICATION/ALTERATION: March 25, 1992 The Surface Water Utility hereby approves the request for modification/alteration to Core Requirement No. 1: Discharge at the Natural Location and Core Requirement No. 4: Conveyance System, Pump Systems, in compliance with City of Renton Code 4-22 -8 and under the authority of 4-22 - 16. Core Requirement No. 1: Discharge at the Natural Location: METRO contracted with R.W. Beck and Associates with Northwest Hydraulic Consultant's (the City's consultant's preparing the Eastside Green River Watershed Plan)to analyze the impacts of the emergency relief stormwater discharges to the P-1 Channel and Black River Pump Station (BRPS). They found (see endorsed letter by Mike Giseburt, P.E., enclosed) that there would be negligible impacts on the system for up to the 100 year event from these discharges even during the rare occasion that the BRPS was restricted by high flows in the Green River(a conservative assumption Based on this analysis and review there will also be negligible quantity impacts for the proposed discharge from on-site wetponds. Note, water quality and other potential environmental impacts will be addressed by METRO's own SEPA process for these proposed facilities and discharges to the P-1 Channel, and through conformance with the City's Shoreline Master Plan Program and the Washington State Department of Fisheries Hydraulic Project Approval. Core Requirement No. 4: Conveyance System, Pump Systems: The case has been well made by the Brown and Caldwell engineers that METRO should be allowed to permanently employ a pump to pump surface water to the wetponds they will construct for treatment and to deviate from the storage requirements. The objectives of safety, function, appearance, environmental protection and maintainability will not only be met but most will be exceeded by METRO's proposed pump system. METRO is now obligated to proceed without delay on development of the permanent wetpond/wetland surface water treatment system. This modification/alteration approval appends, but does not compromise the variance decision and conditions previously made by the City of Renton's Hearing Examiner. I know the City and others will be expecting METRO' compliance with the conditions set forth by the Hearing Examiner and it will provide a unique opportunity for METRO to showcase the years of work and investment they have made in advancing the understanding the treatment methodologies for surface water. Please contact me or Ron Straka at 5547 if you have any questions regarding this approval. RP:rp:METMOD.DOC cc Ron Straka enclosures R.W. BECK AND ASSOCIATES 2101 Fourth Avenue,Suite 600■Seattle,Washington 9817.1.2375■USA F C B 17 1992 Telephone(206)441.7500■Fax(206)4414964 Consulting,(206)4414962 Engineering Telex 4990402 SECKSEA CITY OF RENTON Engineering Dept. WW-1421-AAl-AA February 14, 1992 3023 Mr. Randall Parsons, Utility Supervisor Storm Water/Waste Water Utility Systems Division City of Renton 200 Mill Avenue South Renton, WA 98055 Dear Randall: Subject: Metro Treatment Plant Expansion Project Review of Storm Water Diversion at the Metro Treatment Plant in Renton We are pleased to submit the results of the Task 1 work for the subject project. The analysis was performed by Northwest Hydraulic Consultants (NHC)and reviewed by our office. Copies of their calbulations and analysis are attached. The purpose of the work was to estimate the increase in runoff volume received at the Black River Pump Station (BRPS) forebay resulting from the proposed Metro diversion durirlg an extreme high Green River flow condition. The analysis included using the HSPF hydrology developed as a part of the FSGRW Plan. More specifically, the simulation included the local 100-year flood control storage event under current land use conditions in coincidence with high Green River flows. Based on the work by NHC, the predicted increase in forebay elevations would be 0.07 feet(approximately 1 inch), This rise in elevation corresponds to an increase in volume received at the forebay of approximately 1.5 ac-ft during a period in which the forebay is filled to approximately elevation 6 (storage 132 ac-ft). Based on this analysis, the contribution from the proposed Metro emergency relief flow into Springbrook Creek will result in a negligible impact to the system. Boston,MA•Columbus,NE•Denver,CO•Indianapolis,IN•Minneapolis,MN Nashvillq IN•Orlando,FL■Phoenix,AZ■Sacramento,CA•Seattle,WA A R,,,I,d Paper Vralna Mr. Randall Parsons, Utility Supervisor City of Renton - 2 - February 14, 1992 Per your request, we have also compared these results to the floodplain requirements as set forth in the King County Surface Water Design Manual, Special Requirement #8. This requirement states that the increased volume of runoff from a proposed project may not increase the 100-year flood plain elevation of a lake, wetland, or closed depression more than 0.1 feet. The Springbrook Creek System is similar to a closed depression because it has a restricted outlet, the BRPS, which must limit discharges during periods of high Green River flow. Based on this analysis, the proposed project would meet the requirements of Special Requirement #8 since the predicted increase in the Forebay is less than 0.1 feet. We do not believe that performing the work under Task 2 would be beneficial. Performing a detailed simulation using HSPF/FEQ would more accurately estimate the elevation in the forebay, however the relative change in elevation and the increase in runoff volume at the forebay from the Metro diversion would be nearly the same as predicted by the HSPF analysis. We would be happy to meet with you to discuss the results of the analysis. If you have any questions, please contact our office. Gj S. Very truly yours, of w S' , c R. W. BECK AND ASSOCIATES .q 24055 ¢ ��oNat>NG� Mich el S. Gi eburt Project Engineer EXPIRES: 12- 9Z MSG/ato Enclosure c: Joe Fernandes, Manager Metro Treatment Plant Expansion OASO.029) R.W.BECK AND ASSOCIATES northwest hydraulic consultants inc. �L edmonton 2201770th avenue s. 9ECEIVCD Vancouver kent,washington 96032 (206)672-0218 JAN 22 1992 Seattle R.W.EECK&ASSOC,,, —S REPTTI F Ur^c1a r.,rTgN January 21, 1992 File 20577 Mike S. Giseburt WORK ORDER uH.-/Yz/ -qq R.W. Beck and Associates FILE COPY 30z 3 2101 Fourth Avenue, Suite 600 ENCLOSURE FILED IN Seattle, WA 98121-2375 (S) Dear Mike: RE: Renton METRO Treatment Plant - HSPF Modeling - Task 1 The purpose of this memorandum is to summarize the procedure followed and results obtained in regard to modeling the diversion of storm water from the METRO Treatment Plant (NITP) at Renton into Springbrook Creek. The results summarized here pertain to Task 1 of our scope of work. The Hydrologic Simulation Program - Fortran (HSPF) was used to estimate the Black River Pump Station (BRPS) 100-year storage condition runoff hydrograph from the MTP. During this event, operation of the BRPS is constrained by flows in the Green River. According to information extracted from Table 4 of the Brown and Caldwell report, runoff from 28 acres of pervious area and 12 acres of impervious area in the MTP should be diverted into Springbrook Creek. Hydrographs for Springbrook Creek and MTP were computed using the same multiplying factor derived for the 100-year storage condition for the BRPS, under the current conditions modeling of the East Side Green River watershed. Enclosed,--you will find four pages of computer printout summarizing the results. The event under simulation was from November 29 to December 18, 1975. The simulated peak flow from the MTP to Springbrook Creek was 3.45 cfs and the volume delivered, during the time interval in which the BRPS was constrained by flows in the Green River, was 1.5 acre-ft. The constraint took place between 1000 and 2200 hours of December 3rd. The addition of 1.5 acre-ft will increase the 100-year storage volume required at the BRPS from 132 acre-ft to 133.5 acre-ft which translates into an increase in elevation of 0.07 ft.. These last values are rather approximate and conservative, since the operation of the BRPS was not simulated. RIVER ENGINEERING / HYDRAULIC MODEL TESTING / HYDRAULIC ANALYSIS AND DESIGN / COASTAL ENGINEERING HYDROLOGY / SEDIMENTATION ENGINEERING / NUMERICAL MODELING / APPLIED RESEARCH / FORENSIC ENGINEERING _ Mike S. Giseburt 2 January 21, 1992 I look forward to hearing your comments about these results. Please contact me if you have any questions or require further information. Yours truly, NORTHWEST H ULIC CONSULTANTS INC, 4 Luis G. vid, Ph.D. LGC:jm northwest hydraulic consultants inc. const. Inflow Year Month Day Hour Time NTP BRPS Green R. BRPS BRPS ) (hr) Runoff Inflow Flow Const. ? Outflow Outflow (cfs) (cfs) (cfs) (cis) ? 1975 12 2 1 1 0.23 86.30 7651 No 1975 12 2 2 2 0.27 94.05 $237 No 1975 12 2 3 3 1.12 137.94 6600 No 1975 12 2 4 4 1.15 127.27 8941 No 1975 12 2 5 5 1.10 222.67 9260 Yes 2562 No 1975 12 2 6 6 0.77 240.43 9557 Yes 2562 No 1975 12 2 7 7 1.44 288.76 9831 Yes 2562 No 1975 12 2 8 8 0.96 294.92 10082 Yes 1739 No 1975 12 2 9 9 0.43 288.99 10311 Yes 1739 No 1975 12 2 10 10 0.43 225.20 10518 Yes 1439 No 1975 12 2 11 11 0.53 261.52 10702 Yes 1439 No 1975 12 2 12 12 0.98 280.78 10864 Yes 1439 No 1975 12 2 13 13 0.91 292.87 11004 Yes 925 No 1975 12 2 14 14 1.37 333.45 11121 Yes 925 No 1975 12 2 15 15 1.59 371.75 11216 Yes 925 No 1975 12 2 16 16 1.42 397.86 11288 Yes 925 No 1975 12 2 17 17 2.34 473.90 11338 Yes 925 No 1975 12 2 18 18 1.24 452.03 11366 Yes 925 No 1975 12 2 19 19 1.41 487.01 11371 Yes 925 No 1975 12 2 20 20 3.67 578.09 11354 Yes 925 No 1975 12 2 21 21 3.45 646.49 11314 Yes 925 No 1975 12 2 22 22 2.25 664.85 11252 Yes 925 No 1975 11 2 13 23 1.38 662.91 11168 Yes 925 No 1975 12 2 24 24 1.10 636.69 11061 Yes 925 No 1975 12 3 1 26 6.83 595.88 11061 Yes 925 No 1575 12 3 2 26 0.74 $61.14 11176 Yes 92S No 1975 12 3 3 27 0.65 524.86 11283 Yes 925 No 1975 12 3 4 28 0.64 488.03 11380 Yes 925 No 1975 12 3 5 29 0.55 450.98 11467 Yes 925 No 1975 12 3 6 30 0.52 415.64 11545 Yes 411 Yes 1975 12 3 7 31 0.51 381.33 11614 Yes 411 No 1975 12 3 8 32 1.61 375.74 11673 Yes 411 No 1975 12 3 9 33 1.55 400.14 11723 Yes 411 No 1975 12 3 10 34 1.52 424.65 11764 Yes 411 Yes 1975 12 3 11 35 1.05 426.70 11795 Yes 411 Yes 1975 12 3 12 36 1.24 438.10 11817 Yes 411 Yes 1975 12 3 13 37 1.15 434.11 11830 Yes 411 Yes 1975 12 3 14 38 1.44 454.97 11833 Yes 411 Yes 1975 12 3 15 39 1.80 488.60 11826 Yes 411 Yes 1975 12 3 16 40 1.94 522.92 11811 Yes 411 Yes 1975 12 3 17 41 2.00 $55.64 11786 Yes 411 Yes 1975 12 3 IS 42 1.66 564.64 11751 Yes 411 Yes 1975 12 3 19 43 1.43 567.72 11708 Yes 411 Yes 1975 12 3 20 44 0.92 543.89 11655 Yes 411 Yes' 1975 12 3 21 45 1.64 535.80 11592 Yes._ 411 Yes 1975 12 3 22 46 1.18 521.55 11520 Yes 411 Yes 1975 12 3 23 47 1.29'. 521.21 s 11439 Yes 925 No 1975 12 3 24 48 1.02 565.13 11348 Yes 925 No 1975 12 4 1 49 1.09. 500.80 11267 Yes 925 No 1975 12 4 2 50 O.W 476.29 11205 Yes 925 No 1975 12 4 3 $1 0.63- 448.48 11149 Yes 925 No 1975 12 4 4 52 6.55 417.13 11198 Yes 925 No 1975 12 4 5 ' 53 0.48 386.23 11852 Yes 925 No 1975 12 4 6 54 6.44 361.27 11012 Yes 925 No 1975 12 4 7 55 8.41 338.69 10976 Yes 1439 No 1925 12 4 8 56 e.38 316.46 10946 Yes 1439 No 1975 12 4 9 57 0.38 296.74 10921 Yes 1439 No 1975 12 4 10 58 0.35 279.26 10901 Yes 1439 No 1975 12 4 11 59 0.33 264.59 10882 Yes 1439 No 1975 12 4 12 60 0.31 25e.80 10872 Yes 1439 No 1975 12 4 13 61 0.29 237.92 10873 Yes 1439 No 192S 12 4 14 62 0.28 226.66 10874 Yes 1439 No 1975 12 4 15 63 0.26 217.17 1088e Yes 1439 No 1925 12 4 16 64 0.25 208.05 10892 Yes 1439 No 1975 12 4 17 65 0.24 199.84 10908 Yes 1439 No 1975 12 4 18 66 0.24 192:09 10930 Yes 1439 No 1975 12 4 19 67 0.21 184.91 16957 Yes 1439 No 1975 12 4 20 68 0.21 178.18 10990 Yes 1439 No 1975 12 4 21 69 0.20 172.25 11027 Yes 925 No 1925 12 4 22 70 0.20 166.67 11070 Yes 925 No 1975 12 4 23 71 0.18 161.42 11118 Yes 925 No 1975 12 4 24 72 0.18 156.52 11171 Yes 925 No 1975 12 5 1 73 0.16 151.73 11220 Yes 925 No 1975 12 5 2 74 0.16 147.17 11258 Yes 925 No 1975 12 5 3 75 e.15 143.07 11294 Yes 925 No 1975 12 5 4 76 6.15 139.08 11326 Yes 925 No 1975 12 5 5 77 0.14 135.32 11355 Yes 925 No 1975 12 5 6 78 0.14 131.78 11381 Yes 925 No 1975 12 5 7 79 0.14 128.36 11404 Yes 925 No 1975 12 5 8 80 0.12 125.29 11424 Yes 925 No 1925 12 5 9 el 0.12 122.09 11441 Yes 925 No 1925 12 5 10 82 0.12 119.13 11454 Yes 925 No 1975 12 5 11 83 6.11 116.39 11465 Yes 925 No 197S 12 5 12 64 8.11 113.54 11472 Yes 925 No 1975 12 5 13 85 0.11 111.04 11476 Yes 925 No 1975 12 5 14 86 0.16 108.64 11477 Yes 925 No 1975 12 5 15 87 0.16 106.13 11475 Yes 925 No 1975 12 5 16 88 0.10 le3.85 11470 Yes 925 No 1975 12 5 17 89 0.08 101.69 11462 Yes 925 No 1975 12 5 18 90 0.08 99.S2 11450 Yes 925 No 1975 12 5 19 91 0.08 97.36 11436 Yes 925 No 1975 12 5 20 92 0.08 95.19 11418 Yes 925 No 1975 12 5 21 93 0.67 93.25 11397 Yes 925 No 1975 12 5 22 94 4.07 91.31 11373 Yes 925 No 1975 12 5 23 95 6.07 89.38 11346 Yes 925 No 1976 12 5 24 96 0.07 87.55 11316 Yes 925 No 1975 12 6 1 97 1.07 85.73 11291 Yes 925 No 1925 12 6 2 98 0.07 84.02 11276 Yes 925 No 1975 12 6 3 99 1.06 82.31 11261 Yes 925 No 1975 12 6 4 100 0.66 80.71 11248 Yes 925 No 1975 12 6 5 111 0.06 79.12 11235 Yes 925 No 1975 12 6 6 102 6.06 77.52 11224 Yes 925 No 1975 12 6. 7 103 0.86 76.04 11213 Yes 925 No 1975 12 6 8 104 0.06 74.56 11204 Yes 925 No 1975 12 6 9 165 0.06, . 73.19 11195 Yes 925 No 1975 12 6 10 106 1.66- 71.82 11188 Yes 925 No 1975 12 6 11 107 6.66 70.45 11182 Yes 925 No 1976 12 6 12 168 1.06 69.08 11177 Yes 925 No _ 1975 . , 12 6 13 109 6.64 67.83 -11173 Yes 925 No 1975 11 6 14 110 0.04- 66.46 11169 Yes 925 No 1975 12 6 15 111 0.04 65.32 11167 Yes 925 No 1975 12 6' 16 112 0.64 64.18 11166 Yes 925 No 1975 12 6 17 113 0.64 63.04 11166 Yes 925 No 1975 12 6 18 114 0.04 61.90 11167 Yes 925 No 1975 12 6 19 115 6.04 60.88 11169 Yes 925 No 1975 12 6 20 116 0.04 59.85 11173 Yes 925 No 1975 12 6 21 117 0.04 56.82 11172 Yes $25 No 1975 12 6 22 118 0.04 57.91 11182 Yes 925 No 1975 12 6 23 119 0.04 57.11 11188 Yes 925 No 1975 12 6 24 126 0.04 56.20 11195 Yes 925 No 1975 12 7 1 121 0.04 55.29 11195 Yes 925 No 1975 12 7 2 122 e M 54.49 11221 Yes 925 No 1975 12 7 3 123 0.04 53.58 11243 Yes 925 No 1975 12 7 4 124 e M 52.67 11260 Yes 925 No 1S75 12 7 5 125 0.64 51.87 11274 Yes 925 No 1975 12 7 6 126 0.43 57.57 11283 Yes 925 No 1975 12 7 7 127 0.88 83.90 11288 Yes 925 No 1975 12 7 8 128 1.67 153.18 11289 Yes 925 No 1975 12 7 9 129 1.68 221.84 - 11286 Yes 925 No 1925 12 7 10 13e 1.08 262.43 11279 Yes 925 No 1975 12 7 11 131 0.86 281.69 12100 Yes 0 Yes 1975 12 7 12 132 0.75 276.56 11268 Yes 925 No 1975 12 7 13 133 0.41 266.60 11253 Yes 925 No 1975 12 7 14 134 0.37 250.00 11233 Yes 925 No 1975 12 7 15 135 0.28 231.53 11210 Yes 925 No 1975 12 7 16 136 e.25 216.03 11182 Yes 925 No 1975 12 7 17 137 0.25 200.98 11150 Yes 925 No 1975 12 7 18 138 0.38 193.06 11114 Yes 925 No 1975 12 7 . 19 139 0.58 197.45 11074 Yes 925 No 1975 12 7 20 140 0.34 190.38 11036 Yes 925 No 1975 12 7 21 141 0.30 183.88 10982 Yes 1439 No 1975 12 7 22 142 8.23 171.11 10930 Yes 1439 No 1975 12 7 23 143 6.21 158.92 10873 Yes 1439 No 1925 12 7 24 144 0.18 148.88 10813 Yes 1439 No 1975 12 8 1 145 0.18 140.68 10778 Yes 1439 No 1975 12 8 2 146 e.32 139.99 10237 Yes 1439 No 1975 11 8 3 147 0.40 143.98 10697 Yes 1439 No 1975 12 8 4 148 0.23 141.02 10658 Yes 1439 No 1975 12 8 5 149 0.32 142.61 10620 Yes 1439 No 1975 12 8 6 150 0.36 143.98 leS83 Yes 1439 No 1975 12 8 7 151 6.30 143.75 10547 Yes 1439 No 1975 12 8 8 152 0.21 139.99 10513 Yes 1439 No 1975 12 8 9 153 8.18 133.95 10480 Yes 1739 No 1975 12 8 10 154 0.15 126.77 10447 Yes 1739 No 1975 12 8 11 155 6.14 120.50 10416 Yes 1739 No 1975 12 8 12 156 0.12 114.68 10387 Yes 1739 No 1975 12 8 13 157 0.12 109.21 10358 Yes 1739 No 1975 12 8 14 158 0.10 103.97 10331 Yes 1739 No 1975 12 8 15 159 0.10 99.07 10304 Yes 1739 No 1975 12 8 16 160 0.10 94.62 10278 Yes 1739 No 1975 12 8 17 161 0.09 90.63 16254 Yes 1739 No 1975 12 8 18 162 0.09 86.75 10231 Yes 1739 No 1975 12 8 19 163 0.09 83.45 16209 Yes 1239 No 1975 12 8 20 164 0.09 80.14 10189 Yes 1739 No 1975 12 8 21 165 0.07 77.29 10169 Yes 1739 No 1975 12 8 22 166 0.17 74.78 10151 Yes 1739 No 1975 12 8 23 167. 0.07- 72.39 10133.Yes 1739 No 1975 12 8 24 168 0 A7 - 70.22 10117 Yes 1739 No 1925 12 9 1 169 0.06; 68.40 , 10102 Yes 1739 No 1975 12 9 2 176 0.06 66.69 10087 Yes 1739 No 1975 12 9 3 171 6.06 64.98 10070 Yes 1739 No 1975 12 9 4 172 4.06 63.27 10052 Yes 1739 No 1975 12 9 5 173 0.06 61.96 10033 Yes 1739 No 1975 12 9 6 174 6.06 66.53 10013 Yes 1739 No 1975 12 9 7 275 0.06 59.17 9991 Yes 2150 No 1975 12 9 8 176 e.05 56.03 9968 Yes 2150 No ' 1975 12 9 9 177 e.05 57.00 9944 Yes 2150 No 1975 12 9 10 176 OAS 55.97 9919 Yes 2150 No 1975 12 9 11 179 0.05 54.83 9892 Yes 2150 No 1575 12 9 12 180 0.05 53.81 9864 Yes 2150 No 1975 12 9 13 181 0.05 52.90 9635 Yes 2150 No 1975 12 9 14 182 0.05 $1.98 9504 Yes 2150 No 1975 12 9 15 183 0.05 51.19 9773 Yes 2150 No 1975 12 9 16 184 0.05 50.39 9740 Yes 2150 No 1975 12 9 17 185 e.05 49.20 97e6 Yes 2150 No 1975 12 9 18 186 0.10 50.27 9670 Yes Me No 1975 12 9 19 187 0.18 54.26 9634 Yes 2150 No 1975 12 9 20 188 0.21 58.94 9596 Yes 2150 No 1975 12 9 21 169 0.19 63.16 9556 Yes 2150 No 1975 12 9 22 190 0.23 69.31 9516 Yes 2150 No 1975 12 9 23 191 0.29 76.95 9474 Yes 2562 No 1975 12 9 24 192 0.31 84.59 9431 Yes 2562 No 1975 12 16 1 193 0.16 65.73 9409 Yes 2562 No 1975 12 10 2 194 0.13 66.30 9404 Yes 2562 No 1975 12 10 3 195 0.15 85.61 9394 Yes 2562 No 1975 12 10 4 196 0.11 82.54 9381 Yes 2562 No 1975 12 10 5 197 0.09 29.91 9364 Yes 2562 No 197S 12 1B 6 198 0.07 76.95 9342 Yes 2562 No 1975 12 10 7 199 0.06 73.53 9316 Yes 2562 No 1975 12 10 8 200 0.06 70.34 9286 Yes 2562 No 1975 12 10 9 201 0.06 67.37 9252 Yes 2562 No 1975 12 10 10 2e2 OJS 64.52 9214 Yes 2562 No 1975 12 10 11 203 0.05 62.13 9171 Yes 2562 No 1925 12 10 12 204 0.05. $9.51 9124 Yes 2562 No 1975 12 10 13 205 0.05 $7.34 9074 Yes 2562 No 1975 12 10 14 206 0.05 55.40 9019 Yes 2562 No 1975 12 10 15 207 0.04 53.24 8959 No 197S 12 10 16 208 0.04 51.41 8896 No 1975 12 16 17 209 0.04 49.70 8829 No 1975 12 10 18 210 0.04 48.22 8257 No 1975 12 10 19 211 0.04 46.85 8681 No 1975 12 10 20 212 0.04 45.71 8601 No 1975 12 10 21 213 0.04 44.80 8517 No 1975 12 10 22 214 0.04 44.ee 8429 No 1975 12 10 23 215 0.04 43.21 8336 No 1975 12 10 24 216 0.04 42.52 8239 No CITY OF RENTON MEMORANDUM DATE: April 27, 1992 TO: Don Erickson Gregg Zimmerman Randall Parsons Margaret Pullar FROM: Paul Forsander*GfA4e�t� SUBJECT: Function Numbers For Metro Waste Water Treatment Plant File No. SA; SM; SP:040-91 We now have a signed agreement to cover staff Costs for special reviews associated with the Metro Treatment Plant Expansion. The Work Order Number for this project is 79260. Please use the following function numbers on your time sheets: Category Budgeted Hours Function No. 1. Storm water variance/modification/review 130 4063 2. Perimeter Landscaping Plan Review. 130 4029 3. Site Plan and Environmental review of revised site utilities 100 4023 4. Project Management/Administration/Coordination. 100 4021 5. City Attorney reviews. 25 N/A 6. Wetland Review. 130 4022 R.W. BECK ANDAND A� 2101 Fourth Avenue,Suite 600■Seattle,Washington 98121.2375■USA 1 'L B 17 1992 Telephone(206)441.7500■Fax(206)441-4964 Consulting,(206)441.4962 Engineering Telex 4990402 BECKSEA CITY OF R[NTON Engineering Dept. WW-1421-AAl-AA February 14, 1992 3023 Mr. Randall Parsons, Utility Supervisor Storm Water/Waste Water Utility Systems Division City of Renton 200 Mill Avenue South Renton, WA 98055 Dear Randall: Subject: Metro Treatment Plant Expansion Project Review of Storm Water Diversion at the Metro Treatment Plant in Renton We are pleased to submit the results of the Task 1 work for the subject project. The analysis was performed by Northwest Hydraulic Consultants (NHC)and reviewed by our office. Copies of their calculations and analysis are attached. The purpose of the work was to estimate the increase in runoff volume received at the Black River Pump Station (BRPS) forebay resulting from the proposed Metro diversion during an extreme high Green River flow condition. The analysis included using the HSPF hydrology developed as a part of the ESGRW Plan. More specifically, the simulation included the local 100-year flood control storage event under current land use conditions in coincidence with high Green River flows. Based on the work by NHC, the predicted increase in forebay elevations would be 0.07 feet(approximately 1 inch). This rise in elevation corresponds to an increase in volume received at the forebay of approximately 1.5 ac-ft during a period in which the forebay is filled to approximately elevation 6 (storage 132 ac-ft). Based on this analysis, the contribution from the proposed Metro emergency relief flow into Springbrook Creek will result in a negligible impact to the system. Boston,MA■Columbus,NE■Dense,CO a Indianapolis,1N a Minneapolis,MN Nashville,TN•OrU,do,FL•Phoenix,AZ■Sacramento,CA•Seattle,WA ..nied i'""" 1" 'h„c Mr. Randall Parsons, Utility Supervisor City of Renton - 2 - February 14, 1992 Per your request, we have also compared these results to the floodplain requirements as set forth in the King County Surface Water Design Manual, Special Requirement #8. This requirement states that the increased volume of runoff from a proposed project may not increase the 100-year flood plain elevation of a lake, wetland, or closed depression more than 0.1 feet. The Springbrook Creek System is similar to a closed depression because it has a restricted outlet, the BRPS, which must limit discharges during periods of high Green River flow. Based on this analysis, the proposed project would meet the requirements of Special Requirement #8 since the predicted increase in the Forebay is less than 0.1 feet. We do not believe that performing the work under Task 2 would be beneficial. Performing a detailed simulation using HSPF/FEQ would more accurately estimate the elevation in the forebay, however the relative change in elevation and the increase in runoff volume at the forebay from the Metro diversion would be nearly the same as predicted by the HSPF analysis. We would be happy to meet with you to discuss the results of the analysis. If you have any questions, please contact our office. 1, S. GIS Very truly yours, pF w L�yi Ltd R. W. BECK AND ASSOCIATES A '4055 � C� < �F `QFCISI'6TlF9 �v 1�4 �SSIONAL kr' Michael S. Gi eburt Project Engineer EXPIRES: 1 MSG/ato Enclosure c: Joe Fernandes, Manager Metro Treatment Plant Expansion (MS0.0m R.W.BECK AND ASSOCIATES northwest hydraulic consultants inc. ZL edmonton 22017701h avenue s. ft EcsINEI) vancouver kent,washington 98032 (206)872-0218 JAN 22 1992 seattle a.w.Erac AssoCIA-,ES SF/.Tt'!c lt.•^cHl1•r,TnN January 21, 1992 Ho 20577 Mike S. Giseburt WORK ORDER 44.-/Yz/ -Aq/-AA1 R.W. Beck and Associates FILE COPY 30Z3 2101 Fourth Avenue, Suite 600 ENCLOSURE FILED IN Seattle, WA 98121-2375 (S) Dear Mike: RE: Renton METRO Treatment Plant - HSPF Modeling - Task 1 The purpose of this memorandum is to summarize the procedure followed and results obtained in regard to modeling the diversion of storm water from the METRO Treatment Plant (MTP) at Renton into Springbrook Creek. The results summarized here pertain to Task 1 of our scope of work. The Hydrologic Simulation Program - Fortran (HSPF) was used to estimate the Black River Pump Station (BRPS) 100-year storage condition runoff hydrograph from the MTP. During this event, operation of the BRPS is constrained by flows in the Green River. According to information extracted from Table 4 of the Brown and Caldwell report, runoff from 28 acres of pervious area and 12 acres of impervious area in the MTP should be diverted into Springbrook Creek. Hydrographs for Springbrook Creek and MTP were computed using the same multiplying factor derived for the 100-year storage condition for the BRPS, under the current conditions modeling of the East Side Green River watershed. Enclosed you will find four pages of computer printout summarizing the results. The event under simulation was from November 29 to December 18, 1975. The simulated peak flow from the MTP to Springbrook Creek was 3.45 cfs and the volume delivered, during the time interval in which the BRPS was constrained by flows in the Green River, was 1.5 acre-ft. The constraint took place between 1000 and 2200 hours of December 3rd. The addition of 1.5 acre-ft will increase the 100-year storage volume required at the BRPS from 132 acre-ft to 133.5 acre-ft which translates into an increase in elevation of 0.07 ft.. These last values are rather approximate and conservative, since the operation of the BRPS was not simulated. RIVER ENGINEERING / HYDRAULIC MODEL TESTING / HYDRAULIC ANALYSIS AND DESIGN / COASTAL ENGINEERING HYDROLOGY / SEDIMENTATION ENGINEERING / NUMERICAL MODELING / APPLIED RESEARCH / FOREN51C ENGINEERING Mike S. Giseburt 2 January 21, 1992 I look forward to hearing your comments about these results. Please contact me if you have any questions or require further information. Yours truly, NORTHWEST H ULIC CONSULTANTS INC. ,7 Luis G. avid, Ph.D. LGC.jm northwest hydraulic consultants inc. Const. Inflow Year Month Day Hour floe HIP BRPS Green R. BRPS BRPS ) (hr) Runoff Inflow Flow Const. ? outflow Outflow (cfs) (cfs) (cfs) (cfs) ? 1975 12 2 1 1 0.23 86.38 7851 No 1975 12 2 2 2 0.27 94.05 8237 No 1975 12 2 3 3 1.12 137.94 8600 No 1975 12 2 4 4 1.15 177.27 8941 No 1925 12 2 5 5 1.10 222.87 9260 Yes 2562 No 1975 12 2 6 6 0.77 240.43 9557 Yes 2562 No 1975 12 2 7 7 1.44 288.76 9831 Yes 2562 No 1975 12 2 8 8 6.96 294.92 10082 Yes 1739 No 1975 12 2 9 9 0.43 288.99 10311 Yes 1739 No 1975 12 2 10 10 0.43 275.20 10518 Yes 1419 No 1975 12 2 11 11 0.53 261.52 10702 Yes 1439 No 1975 12 2 12 12 6.98 280.78 10864 Yes 1439 No 1975 12 1 13 13 6.91 292.87 11004 Yes 925 No 1975 12 2 14 14 1.37 333.45 11121 Yes 925 No 1975 12 2 15 15 1.59 371.75 11216 Yes 925 No 1975 12 2 16 16 1.42 397.86 11288 Yes 925 No 1975 12 2 17 17 2.34 473.90 11338 Yes 925 No 1975 12 2 18 18 1.24 457.63 11366 Yes 925 No 1975 12 2 19 19 1.41 487.11 11371 Yes 925 No 1975 12 2 20 20 3.07 578.09 11354 Yes 925 No 1975 12 2 21 21 3.45 646.49 11314 Yes 925 No 1975 12 2 22 22 2.25 664.85 11252 Yes 925 No 1975 12 2 23 23 1.38 662.91 11168 Yes 925 No 1975 12 2 24 24 1.10 636.69 11061 Yes 925 No 1975 12 3 1 25 0.83 595.88 11061 Yes 925 No 1925 12 3 2 26 6.74 561.34 11176 Yes 925 No 1975 12 3 3 27 1.65 $24.86 11283 Yes 925 No 1975 12 3 4 28 0.60 488.63 11386 Yes 925 No 1975 12 3 5 29 0.55 450.98 11467 Yes 925 No 1975 12 3 6 30 0.52 415.64 11545 Yes 411 Yes 1975 12 3 7 31 0.51 381.33 11614 Yes 411 No 1975 12 3 8 32 1.61 375.74 11673 Yes 411 No 1975 12 3 9 33 1.55 400.14 11723 Yes 411 No 1975 12 3 10 34 1.52 424.65 11764 Yes 411 Yes 1975 12 3 11 35 1.05 426.70 11795 Yes 411 Yes 1975 12 3 12 36 1.24 438.10 11817 Yes 411 Yes 1975 12 3 13 37 1.15 434.11 11836 Yes 411 Yes 1975 12 3 14 38 1.44 454.92 11833 Yes 411 Yes 1975 12 3 15 39 1.84 488.68 11826 Yes 411 Yes 1975 12 3 16 41 1.94 $22.92 11811 Yes 411 Yes 1975 12 3 17 41 2.00 555.64 11786 Yes 411 Yes 1975 12 3 18 42 1.66 $64.64 11751 Yes 411 Yes 1975 12 3 19 43 1.43 567.72 11708 Yes 411 Yes 1975 12 3 21 44 0.92 543.89 11655 Yes 411 Yes' 1975 12 3 21 45 1.64 535.80 11592 Yes , 411 Yes 1975 12 3 22 46 1.08 521.55 11520 Yes 411 Yes 197$ 12 3 23 47 1.29'. $21.21 11439 Yes 925 No 1975 12 3 24 48' 1.02' 505.13: 11348 Yes 925 No 1975 12 4 1 49 1.09 . 564 A 11267 Yes 925 No 1975 12 4 2 58 0.02 . 476.29 11205 Yes 925 No 1975 12 4 3 51 1.63- 448.48 11149 Yes 925 No 1975 12 4 4 52 0.55 417.13` 11098 Yes 925 No 1975 12 4 5 53. 0.48 386.23 11652 Yes 925 No 1975 12 4 6 54 1.44 361.27 11112 Yes 925 No 1975 12 4 7 55 1.41 338.69 10976 Yes 1439 No 1975 12 4 8 56 0.38 316.46 10946 Yes 1439 No 1975 12 4 9 57 0.38 296.74 10921 Yes 1439 No 1975 12 4 10 58 0.35 279.76 10901 Yes 1439 No 1975 12 4 11 59 0.33 264.59 10887 Yes 1439 No 1975 12 4 12 60 0.31 250.80 10877 Yes 1439 No 1975 12 4 13 61 0.29 237.92 10873 Yes 1439 No 1975 12 4 14 62 0.28 226.86 10874 Yes 1439 No 1975 12 4 15 63 0.26 217.17 10860 Yes 1439 No 1975 12 4 16 64 0.25 208.65 10892 Yes 1419 No 1975 12 4 17 65 0.24 199.84 10908 Yes 1439 No 1975 12 4 16 66 0.24 192.09 10930 Yes 1439 No 1975 12 4 19 67 0.21 184.91 10957 Yes 1439 No 197$ 12 4 20 68 1.21 178.18 10990 Yes 1439 No 1975 12 4 21 69 0.20 172.25 . 11027 Yes 925 No 1925 12 4 22 70 0.20 166.67 11670 Yes 925 No 1975 12 4 23 71 0.18 161.42 11118 Yes 925 No 1975 12 4 24 72 0.18 156.52 11171 Yes 925 No 1975 12 5 1 73 0.16 151.73 11220 Yes 925 No 1975 12 5 2 74 0.16 147.17 11258 Yes 925 No 1975 12 5 3 75 0.15 143.67 11294 Yes 925 No 1975 12 5 4 76 0.15 139.68 11326 Yes 925 No 1975 12 5 5 77 0.14 135.32 11356 Yes 925 No 1975 12 5 6 78 6.14 131.78 11381 Yes 925 No 1975 12 5 7 79 6.14 128.36 11404 Yes 925 No 1975 12 5 8 80 0.12 125.29 11424 Yes 925 No 1975 12 5 9 81 4.12 122.09 11441 Yes 925 No 1975 12 5 16 82 0.12 119.13 11454 Yes 925 No 1975 12 5 11 83 0.11 116.39 11465 Yes 925 No 1975 12 5 12 84 4.11 113.54 11472 Yes 925 No 1975 12 5 13 IS 0.11 111.04 11476 Yes 925 No 1975 12 5 14 86 0.10 168.64 11477 Yes 925 No 1975 12 5 15 87 8.16 106.13 11475 Yes 925 No 1975 12 5 16 88 0.10 103.85 11470 Yes 925 No 1975 12 5 17 89 0.08 M.69 11462 Yes 925 No 1975 12 5 18 96 1.08 99.52 11450 Yes 925 No 1975 12 5 19 91 0.08 97.36 11436 Yes 925 No 1975 12 5 26 92 0.68 95.19 11418 Yes 925 No 1975 12 5 21 93 0.07 93.25 11397 Yes 925 No 1975 12 S 22 94 0.07 91.31 11373 Yes 925 No 1975 12 5 23 95 0.07 89.38 11346 Yes 925 No 1975 12 5 24 96 6.07 87.55 11316 Yes 925 No 1975 12 6 1 97 6.07 $5.73 11291 Yes 925 No 1975 12 6 2 98 1.Q 84.02 11276 Yes 925 No 1975 12 6 3 99 8.06 82.31 11261 Yes 925 No 1975 12 6 4 100 0.16 88.71 11248 Yes 925 No 1975 12 6 5 111 6.66 29.12 11235 Yes 925 No 1975 12 6 6 102 0.06 77.52 11224 Yes 925 No 1975 12 6. 7 103 0.86 76.04 11213 Yes 925 No 1975 12 6 8 104 0.06 74.56 11264 Yes 925 No 1975 12 6 9 105 1.06 73.19 11195 Yes 925 No 1975 12 6 10 106 0.66 71.82 11188 Yes 925 No 1975 12 6 11 117 1,06 - 21.45 11182 Yes 925 No 1975 12 6 12 108 0.06 69.68 11177 Yes 925 No 1975 12 6 13 109 0.14 67.83 ` 11173 Yes 925 No 1975 12 6 14 111 0.14 66.46 11169 Yes 925 No 1975 12 6 15 111 0.64 66.32 11167 Yes 925 No 1975 12 6 16 112 0.04 64.18 11166 Yes 925 No 1975 12 6 17 113 0.04 63.04 11166 Yes 925 No 1975 12 6 18 114 0.04 61.91 11167 Yes 925 No 1975 12 6 19 115 0.64 60.88 11169 Yes 925 No 1975 12 6 20 116 6.04 59.85 11173 Yes 925 No 1975 12 6 21 117 0.04 58.82 11177 Yes 925 No 1975 12 6 22 118 0.04 57.91 11182 Yes 925 No 1975 12 6 23 119 0.04 57.11 11188 Yes 925 No 1975 12 6 24 120 0.04 $6.20 11195 Yes 925 No 1975 12 7 1 121 0.04 55.29 11195 Yes 925 No 1975 12 7 2 122 0.04 54.49 11221 Yes 925 No 1975 12 7 3 123 0.04 53.58 11243 Yes 925 No 1975 12 7 4 124 0.04 52.67 11260 Yes 925 No 1975 12 7 5 125 0.04 51.87 11274 Yes 925 No 1975 12 7 6 126 6.43 57.57 11283 Yes 925 No 1975 12 7 7 127 0.88 83.90 11288 Yes 925 No 1975 12 7 8 128 1.67 153.16 11289 Yes 925 No 1975 12 7 9 129 1.68 221.64 - 11286 Yes 925 No 1975 12 7 10 131 1.08 262.43 11279 Yes 925 No 1975 12 7 11 131 6.86 281.69 12100 Yes 0 Yes 197S 12 7 12 132 0.75 276.56 11268 Yes 925 No 1975 12 7 13 133 0.41 260.60 11253 Yes 925 No 1975 12 7 14 134 0.37 250.00 11233 Yes 925 No 1975 12 7 15 135 0.28 23 M 11210 Yes 925 No 1975 12 7 16 136 0.25 216.03 11182 Yes 925 No 1975 12 7 17 137 0.25 200.98 11150 Yes 925 No 1975 12 7 18 138 0.38 193.06 11114 Yes 925 No 1975 12 7 19 139 0.58 197.45 11674 Yes 925 No 1975 12 7 20 140 0.34 190.38 11031 Yes 925 No 1975 12 7 21 141 0.38 183.88 10982 Yes 1439 No 1975 12 7 22 142 0.23 171.11 10936 Yes 1439 No 1975 12 7 23 143 0.21 158.92 10873 Yes 1439 No 1975 12 7 24 144 0.18 148.88 10813 Yes 1439 No 1975 12 8 1 145 0.18 140.68 10778 Yes 1439 No 1975 12 8 2 146 6.32 139.99 10737 Yes 1439 No 1975 12 8 3 147 6.40 143.98 10697 Yes 1439 No 1975 12 6 4 140 0.23 141.62 10658 Yes 1439 No 1975 12 0 5 149 6.32 142.61 10621 Yes 1439 No 1975 12 8 6 150 0.36 143.98 10583 Yes 1439 No 1975 12 8 7 151 0.30 143.75 10547 Yes 1439 No 1975 12 8 8 152 0.21 139.99 10513 Yes 1439 No 1925 12 8 9 153 0.10 133.95 10480 Yes 1739 No 1975 12 8 10 154 6.15 126.77 10447 Yes 1739 No 1975 12 8 11 155 0.14 120.5/ 10416 Yes 1739 No 1975 12 8 12 156 0.12 114.68 10387 Yes 1739 No 1975 12 8 13 157 0.12 109.21 1e358 Yes 1739 No 1975 12 6 14 158 6.1/ 163.97 10336 Yes 1739 No 1975 12 8 15 159 0.10 99.07 10304 Yes 1739 No 1975 12 8 16 161 6.10 94.62 10278 Yes 1739 No 1975 12 8 17 161 0.09 90.63 10254 Yes 1739 No 1975 12 0 18 162 0.09 86.75 10231 Yes 1739 No 1975 12 8 19 163 0.09 83.45 10209 Yes 1739 No 1976 12 8 20 164 1.09 $0.14 10189 Yes 1739 No 1975 12 8 21 165 0.67 77.29 10169 Yes 1739 No 1975 12 8 22 166 0.17 74.78 10151 Yes 1739 No 1975 12 0 23 167. 4.07- 72.39 10133 Yes 1739 No 1975 12 8 24 168 /.17Y 70.22 10117 Yes 1739 No 1975 12 9 1 169 0.66: ; 66.40 10102 Yes 1739 No 1975 12 9 2 170 0.06 66.69 16087 Yes 1739 No 1975 12 9 3 171 6.06 64.98 10070 Yes 1739 No 1975 12 9 4 172 0.06 63.27 10052 Yes 1739 No 1975 12 9 5 173 1.06 61.96 10033 Yes 1739 No 1975 12 9 6 174 1.06 60.53 10013 Yes 1739 No 1975 12 9 7 175 6.66 59.17 9991 Yes 2151 No 1975 12 9 8 176 0.05 58.03 9968 Yes 2150 No 1975 12 9 9 177 0.05 57.00 9944 Yes 2150 No 1975 12 9 10 178 0.05 55.97 9919 Yes 2150 No 1975 12 9 it 179 0.05 54.83 9892 Yes 2150 No 1925 12 9 12 180 0.05 53.81 9864 Yes 2150 No 1975 12 9 13 181 0.05 52.90 9835 Yes 2150 No 1975 12 9 14 182 0.05 51.98 9804 Yes 2156 No 1975 12 9 15 183 0.05 51.19 9773 Yes 2150 No 1975 12 9 16 184 0.05 50.39 9740 Yes 2150 No 1975 12 9 17 185 0.65 49.70 9706 Yes 2150 No 1975 12 9 18 186 0.10 $0.27 9671 Yes 2150 No 1975 12 9 19 187 0.18 54.26 9634 Yes 2150 No 1975 12 9 20 188 0.21 58.94 9596 Yes 2150 No 1925 12 9 21 189 0.19 63.16 9556 Yes 2150 No 1975 12 9 12 190 0.23 69.31 9516 Yes 2150 No 1975 12 9 23 191 0.29 76.95 9474 Yes 2562 No 1975 12 9 24 192 1.31 84.59 9431 Yes 2562 No 1975 It 10 1 193 6.16 85.73 9409 Yes 2562 No 1975 12 10 2 194 0.13 86.30 9404 Yes 2562 No 1975 12 10 3 195 0.15 85.61 9394 Yes 2$62 No 1975 12 10 4 196 0.11 $2.54 9381 Yes 2562 No 1975 12 16 5 197 0.69 79.91 9364 Yes 2562 No 1975 12 10 6 198 0.07 26.95 9342 Yes 2562 No 1975 12 10 7 199 0,06 73.53 9316 Yes 2562 No 1975 12 10 8 200 0.06 70.34 9286 Yes 2562 No 1975 12 10 9 201 0.06 67.37 9252 Yes 2562 No 1975 12 10 10 202 0.05 64.52 9214 Yes 2562 No 1975 12 16 11 203 0.05 62.13 9171 Yes 2562 No 1975 12 10 12 204 0.05. 59.51 9124 Yes 2562 No 1975 12 16 13 205 0.05 57.34 9024 Yes 2562 No 1975 12 10 14 206 0.05 55.46 9019 Yes 2562 No 1975 12 10 15 207 0.04 $3.24 8959 No 1975 12 10 16 208 0.04 51.41 8896 No 1975 12 16 17 209 0.04 49.70 8829 No 1975 12 10 18 210 C64 48.22 8757 No 1975 12 10 19 211 0.04 46.85 8681 No 1975 12 10 20 212 0.04 45.71 8601 No 1975 12 10 21 213 6.04 44.80 0517 No 1975 12 10 22 214 0.04 44.00 $429 No 1975 12 10 23 215 8.04 43.21 8336 No 1975 12 10 24 216 8.64 42.52 8239 No R.W. BECK AND ASSOCIAM 2101 Fourth Avenue,Suite 600■Seattle,Washington 98121-2375■USA Telephone(206)441.7500■Fax(206)441.4964 Consulting,(206)441.4962 End' eering Telex 4990402 BECKSEA�i WW-1421-AA1-AA JAN ` 3 19�2 January 22, 1992 3023 Engl oeTIna Dep Mr. Randall Parsons, Utility Supervisor Storm Water/Waste Water Utility Systems Division City of Renton 200 Mill Avenue South Renton, WA 98055 Dear Randall:: Subject: Metro Treatment Plant Expansion Project Review of Storm Water Diversion at the Metro Treatment Plant in Renton Per Metro Contract We are pleased to submit the results of the Task 1 work for the subject project. The analysis was performed by Northwest Hydraulic Consultants (NHC) and reviewed by our office. Copies of their calculations and analysis are attached. The purpose of the work was to estimate the increase in runoff volume received at the Black River Pump Station(BRPS) forebay resulting from the proposed Metro diversion during an extreme high Green River flow condition. The analysis included using the HSPF hydrology developed as a part of the ESGRW Plan. More specifically, the simulation included the local 100-year flood control storage evert under current land use conditions in coincidence with high Green River flows. Based on the work by NHC, the predicted increase in forebay elevations would be 0.07 feet(approximately 1 inch). This rise in elevation corresponds to an increase in volume received at the forebay of approximately 1.5 ac-ft during a period in which the forebay is filled to approximately elevation 6 (storage 132 ac-ft). We do not believe that performing the work under Task 2 would be beneficial. Performing a detailed simulation using HSPF/FEQ would more accurately estimate the elevation in the forebay, however the relative change in elevation and the increase in runoff volume at the forebay from the Metro diversion would be nearly the same as predicted by the HSPF analysis. MSO.025 Boston,MA■Columbus,NE•Denver,CO■Indianapolis,IN■Minneapolis,MN Nashville,TN■Orlando,FL•Phoenix,AZ•Sacrnnento,CA•Seatde,WA ,: A R.cs d,xl Pafrr 11"A'aa Mr. Randall Parsons, Utility Supervisor Storm Water/Waste Water 2 January 22, 1992 We would be happy to meet with you to discuss the results of the analysis. If you have any questions, please contact our office. Very truly yours, R. W. BECK AND ASSOCIATES M ce Gisebu t Project Engineer MG:cs Enclosure c: Joe Fernandes, Manager Metro Treatment Plant Expansion Msc.o2s R.W.BECK AND ASSOCIATES JAN-23-'92 THU 1,1!37 IDs P.ENTON CONSTP. TPAILP. TEL NO! (206) 69�-?�99 f1102 P02 w JOII LL JL "LV 11•11 E R.W. BE, AND ASSOCIATES Fourth and tllanthaid Sulldinw.Suite 600■2101 Fourth Avenue■Seattle.Washino ni 9C lZ1.2375■SSA Tel.phon.(206)441 7500■Fax(206) ill 1962 WCA 499940'HECFSEA WW-1421-AAI-AA January 22, 1992 3023 Mr. Randall Parsons, Utility Supervisor Storm Water/Waste Water Utility Systems Division City of Renton 200 Mill Avenue South Renton, WA 99055 Dear Randall:: Subject: Metro Treatment Plant Etrpanslon Project Review of Storm Water Diversion at the Metro Treatment Plant to Renton We are pleased to submit file results of the Task 1 work for the subject project. The analysis was performed by Northwest Hydraulic Consultants CIZIC)and reviewed by our office, Copies of their calculations and analysis aro attached. The purpose of the work was to estimate the increase in runoff volume received at the Black River Pump Station(BRPS)forebay resulting from the proposed Metro diversion during an extreme high Green River flow condition. The analysis included using the HSPF hydrology developed as a part of the ESGRW Plan. More specifically, the simulation included the local 100-year flood control storage event under current land use conditions in coincidence with high Green River flows. Based on the work by NHC, the predicted increase in forebay elevations would he 0.07 feet (approximately 1 inch). This rise in elevation corresponds to an increase in volume received at the forebay of approximately 1.5 ac-ft during a period in which the forebay is filled to approximately elevation 6 (storage 132 ac-ft). We do not believe that performing the work under Tack 2 wriuld he henaficial. Prrfmminy a detailed simulation using HSPF/FEQ would more accurately estimate the elevation in the forebay, huwcvcr the relative change in elevation and the increase in runoff volume at the forebay from the Metro diversion would be nearly the same as predicted by the HSPF analysis. MS6.025 D..mm MA•Ccl.m6m,NL•II.a.a.,CO•I„dbn.p.d4.1N.blG.navwU..NN Ne.hAJIC TN I011andP,n e rhecn a-Al..'atrememo,CA•Sonic.WA JAN-23—'92 THU 1�1:37 ID:P.ENTON CONSTP. TP.AILP. TEL NO! (206) 60Ih2�00 H102 P03 . _ . JAN 22.92 WED 14141 KW btL K HND H66WIH1t6 rR. NU. �Uo 4414yt� F,-1.,o r , Mr, Randall Parsons, Utility Supervisor Storm Wdtor/Waste Watcr 2 January 22, 1992 We would be happy to meet with you to discuss the results of the analysis. If you have any questions, please contact our office. Very truly yours, N_ W_ BECK AND ASSOCLA'rFS M ee Gisebu t Project Engineer MG:cs Enclosure c: Joe Fernandes, Manager Metro Treatment Plant Expansion raso.ozs R.W.BECK .eNn rra JRN-23-'92 THU 14:36 ID:RaITON CONSTR TP.GIILP. TEL NO! C206) 68,1-24e9 H102 P01 METRO - RENTON III CONSTRUCTION MANAGEMENT TRAILER 1200 MONSTER ROAD SW - M/S RNC RENTON. WASHINGTON 98055 (206) 684-2430 FAX # (206) 684-2488 [`>> FAX COVER SHEET / 31 TO:_nitrl�A1I �9S�caS _ DATE:--z? L2 COMPANY: ---C_rr�--{�-r-. ku.-_✓_��1------------------------- PHONE: -------- FAX SUWECf: M--L-117-er �, �,�,=_- --�--- ----------- TRANSMITTED PAGES (THIS IS PAGE 1) FROM: COMPANY: ---i7u�T�=----------- PHONE: c� j_ FAX R —_-- OFor your uae UFor approval DAs requested OFor your review QFor correcuun ❑Return comments QContact us 0 Copy to: OReturn ❑ Other: ---------------------------- NOTE:- ------------------- ------------ JRN 21 '92 11:19 NW HYDRRULIC CONSLTS 936 P02 r northwest hydraulic consultants inc. edmonton 22017 Toth avenue 6. va ne ou ve r kant.waahington 96032 (206)872-0218 seattle January 21, 1992 � zosri Mike S. Giseburt R.W. Beck and Associates 2101 Fourth Avenue, Suite 600 Seattle, WA 98121-2375 I Dear Mike: RE: Renton METRO Treatment Plant -HSPF Modeling - Task 1 The purpose of this memorandum is to summarize the procedure followed and results obtained in regard to modeling the diversion of storm water from the METRO Treatment Plant (MTP) at Renton into Springbrook Creek. The results summarized here pertain to Task 1 of our scope of work. The Hydrologic Simulation Program - Fortr;m WpF) was used to estimate the Black River Pump Station (BRPS) 100-year storage condition runoff bydrograph from the MTP. During this event, operation of the BRPS is constrained by flows in the Green River. According to information extracted from Table 4 of the Brown and Caldwell report, runoff from 28 acres of pervious area and 12 acres of impervious area in the MTP should be diverted into Springbrook Creek. Hydrographs for Springbrook Creek and MTP were computed using the same multiplying factor derived for the 100-year storage condition for the BRPS, under the current conditions modeling of the Past Side Green River watershed. Enclosed you will find four pages of computer printout summarizing the results, The event under simulation was from November 29 to December 18, 1975. The simulated peak flow from the MTP to Springbrook Creek was 3.45 cfs and the volume delivered, during the time interval in which the BRPS was constrained by flows in the Great River, was 1.5 acre-& Ile constraint took place between 1000 and 2200 hours of December 3rd. The addition of 1.5 acre-ft will increase the 100-year storage volume required at the BRPS from 132 acre-ft to 133.5 acre-ft which translates into an increase in elevation of 0.07 ft.. These last values are rather approximate and conservative, since the operation of the BRPS was not simulated. RIVER FNOINEERING / NYDRAUrIC MODEL TiLTINO / HYDRAULIC ANALV616 ANO DESIGN / COASTAL CNOIN[ERINO HYDROLOGY / SEDIMENTATION FENDINEERINQ / NUMERICAL MODELIND I APPLIED RES RC J FORENSIC ENCINELRINQ I JRN 21 "J2 11:2u NW HYDRRULIC CUNSLTS '336 P63 • Mike S. Giseburt 2 January 21, 1992 I look forward to hearing your comments about these results, Please contact me if you have any questions or require further information. Yours truly, NORTHWEST H ULiC CONSULTANTS INC. 4 Les jG. !vj4id, Fh.D. LGC.jm northwest hydraulic consultants inc. Const. Inflow Year Month Day Hour Time MTP BRPS Green R. BRPS BRPS ) (hr) Runoff Inflow Flow Const. ? Outflow Outflow (cfs) (cfs) (cfs) (cfs) ? 1975 12 2 1 1 0.23 86.30 7851 No 1975 12 2 2 2 0.27 94.05 8237 No 1975 12 2 3 3 1.12 137.94 8600 No 1975 12 2 4 4 1.15 177.27 8941 No 1975 12 2 5 5 1.10 222.87 9260 Yes 2562 No 1975 12 2 6 6 0.77 240.43 9557 Yes 2562 No 1975 12 2 7 7 1.44 288.76 9831 Yes 2562 No 1975 12 2 8 8 0.96 294.92 10082 Yes 1739 No 1975 12 2 9 9 0.43 288.99 10311 Yes 1739 No 1975 12 2 10 10 0.43 275.20 10518 Yes 1439 No 1975 12 2 11 11 0.53 261.52 10702 Yes 1439 No 1975 12 2 12 12 8.98 280.78 10864 Yes 1439 No 1975 12 2 13 13 0.91 292.87 11004 Yes 925 No 1975 12 2 14 14 1.37 333.45 11121 Yes 925 No 1975 12 2 15 15 1.59 371.75 11216 Yes 925 No 1975 12 2 16 16 1.42 397.86 11288 Yes 925 No 1975 12 2 17 17 2.34 473.90 11338 Yes 925 No 1975 12 2 18 18 1.24 457.03 11366 Yes 925 No 1975 12 2 19 19 1.41 487.01 11371 Yes 925 No 1975 12 2 20 20 3.07 578.09 11354 Yes 925 No 1975 12 2 21 21 3.45 646.49 11314 Yes 925 No 1975 12 2 22 22 2.25 664.85 11252 Yes 925 No 1975 12 2 13 23 1.38 662.91 11168 Yes 925 No 1975 12 2 24 24 1.10 636.69 11061 Yes 925 No 1975 12 3 1 25 0.83 595.88 11061 Yes 925 No 1975 12 3 2 26 0.74 561.34 11176 Yes 925 No 1975 12 3 3 27 0.65 524.86 11283 Yes 925 No 1975 12 3 4 28 0.60 488.03 11380 Yes 925 No 1975 12 3 5 29 6.55 450.98 11467 Yes 925 No 1975 12 3 6 30 0.52 415.64 11545 Yes 411 Yes 1975 12 3 7 31 0.51 381.33 11614 Yes 411 No 1975 12 3 8 32 1.01 375.74 11673 Yes 411 No 1975 12 3 9 33 1.55 400.14 11723 Yes 411 No 1975 12 3 10 34 1.52 424.65 11764 Yes 411 Yes 1975 12 3 11 35 1.05 426.70 11795 Yes 411 Yes 1975 12 3 12 36 1.24 438.10 11817 Yes 411 Yes 1975 11 3 13 37 1.15 434.11 11830 Yes 411 Yes 1975 12 3 14 38 1.44 454.97 11833 Yes 411 Yes 1975 12 3 15 39 1.80 488.60 11826 Yes 411 Yes 1975 12 3 16 40 1.94 522.92 11811 Yes 411 Yes 1975 12 3 17 41 2.00 555.64 11786 Yes 411 Yes 1975 12 3 18 42 1.66 564.64 11751 Yes 411 Yes 1975 12 3 19 43 1.43 567.72 11708 Yes 411 Yes 1975 12 3 20 44 0.92 543.89 11655 Yes 411 Yes 1975 12 3 21 45 1.04 535.80 11592 Yes 411 Yes 1975 12 3 22 46 1.08 521.55 11520 Yes 411 Yes 1975 12 3 23 47 1.29 521.21 11439 Yes 925 No 1975 12 3 24 48 1.02 505.13 11348 Yes 925 No 1975 12 4 1 49 1.09 500.80 11267 Yes 925 No 1975 12 4 2 50 0.82 476.29 11205 Yes 925 No 1975 12 4 3 51 0.63 448.48 11149 Yes 925 No 1975 12 4 4 52 0.55 417.13 11098 Yes 925 No 1975 12 4 5 53 0.48 386.23 11052 Yes 925 No 1975 12 4 6 54 0.44 361.27 11012 Yes 925 No 1975 12 4 7 55 0.41 338.69 10976 Yes 1439 No 1975 12 4 8 56 0.38 316.46 10946 Yes 1439 No 1975 12 4 9 57 0.38 296.74 10921 Yes 1439 No 1975 12 4 10 58 0.35 279.76 10901 Yes 1439 No 1975 12 4 11 59 0.33 264.59 10887 Yes 1439 No 1975 12 4 12 60 0.31 250.80 10877 Yes 1439 No 1975 12 4 13 61 0.29 237.92 10873 Yes 1439 No 1975 12 4 14 62 0.28 226.86 10874 Yes 1439 No 1975 12 4 15 63 0.26 217.17 10880 Yes 1439 No 1975 12 4 16 64 0.25 208.05 10892 Yes 1439 No 1975 12 4 17 65 0.24 199.84 10908 Yes 1439 No 1975 12 4 18 66 0.24 192.09 10930 Yes 1439 No 1975 12 4 19 67 0.21 184.91 10957 Yes 1439 No 1975 12 4 20 68 0.21 178.18 10990 Yes 1439 No 1975 12 4 11 69 0.20 172.25 11027 Yes 925 No 1975 12 4 22 70 0.20 166.67 11070 Yes 925 No 1975 12 4 23 71 0.18 161.42 11118 Yes 925 No 1975 12 4 24 72 0.18 156.52 11171 Yes 925 No 1975 12 5 1 73 0.16 151.73 11220 Yes 925 No 1975 12 5 2 74 0.16 147.17 11258 Yes 925 No 1975 12 5 3 75 0.15 143.07 11294 Yes 925 No 1975 12 5 4 76 0.15 139.08 11326 Yes 925 No 1975 12 5 5 77 0.14 135.32 11355 Yes 925 No 1975 12 5 6 78 6.14 131.78 11381 Yes 925 No 1975 12 5 7 79 0.14 128.36 11404 Yes 925 No 1975 12 5 8 80 0.12 125.29 11424 Yes 925 No 1975 12 5 9 81 1.12 122.09 11441 Yes 925 No 1975 12 5 10 82 0.12 119.13 11454 Yes 925 No 1975 12 5 11 83 0.11 116.39 11465 Yes 925 No 1975 12 5 12 84 0.11 113.54 11472 Yes 925 No 1975 12 5 13 85 0.11 111.64 11476 Yes 925 No 1975 12 5 14 86 0.10 108.64 11477 Yes 925 No 1975 12 5 15 87 0.10 106.13 11475 Yes 925 No 1975 12 5 16 88 0.10 103.85 11470 Yes 925 No 1975 12 5 17 89 0.08 101.69 11462 Yes 925 No 1975 12 5 18 90 0.08 99.52 11450 Yes 925 No 1975 12 5 19 91 0.08 97.36 11436 Yes 925 No 1975 12 5 20 92 0.08 95.19 11418 Yes 925 No 1975 12 5 21 93 0.07 93.25 11397 Yes 925 No 1975 12 5 22 94 0.07 91.31 11373 Yes 925 No 1975 12 5 23 95 0.07 89.38 11346 Yes 925 No 1975 12 5 24 96 0.87 87.55 11316 Yes 925 No 1975 12 6 1 97 0.07 85.73 11291 Yes 925 No 1975 12 6 2 98 0.07 84.02 11276 Yes 925 No 1975 12 6 3 99 0.06 82.31 11261 Yes 925 No 1975 12 6 4 100 0.06 80.71 11248 Yes 925 No 1975 12 6 5 101 0.06 79.12 11235 Yes 925 No 1175 12 6 6 102 0.66 77.52 11224 Yes 925 No 1975 12 6 7 103 0.06 76.04 11213 Yes 925 No 1975 12 6 8 104 0.06 74.56 11204 Yes 925 No 1975 12 6 9 105 0.06 73.19 11195 Yes 925 No 1975 12 6 10 106 0.06 71.82 11188 Yes 925 No 1975 12 6 11 107 0.06 70.45 11182 Yes 925 No 1975 12 6 12 108 0.06 69.08 11177 Yes 925 No 1975 12 6 13 109 6.04 67.83 11173 Yes 925 No 1975 12 6 14 110 0.04 66.46 11169 Yes 925 No 1975 12 6 15 111 0.04 65.32 11167 Yes 925 No 1975 12 6 16 112 0.04 64.18 11166 Yes 925 No 1975 12 6 17 113 0.04 63.04 11166 Yes 925 No 1975 12 6 18 114 0.04 61.90 11167 Yes 925 No 1975 12 6 19 115 0.04 60.88 11169 Yes 925 No 1975 12 6 20 116 0.04 59.85 11173 Yes 925 No 1975 12 6 21 117 0.04 58.82 11177 Yes 925 No • 1975 12 6 22 118 0.04 57.91 11182 Yes 925 No 1975 12 6 13 119 0.04 57.11 11188 Yes 925 No 1975 12 6 24 120 0.64 56.20 11195 Yes 925 No 1975 12 7 1 121 0.04 55.29 11195 Yes 925 No 1975 12 7 2 122 0.04 54.49 11221 Yes 925 No 1975 12 7 3 123 6.04 53.58 11243 Yes 925 No 1975 12 7 4 124 0.04 52.67 11260 Yes 925 No 1975 12 7 5 125 0.04 51.87 11274 Yes 925 No 1975 12 7 6 126 0.43 57.57 11283 Yes 925 No 1975 12 7 7 127 0.88 83.90 11288 Yes 925 No 1975 12 7 8 128 1.67 153.10 11289 Yes 925 No 1975 12 7 9 129 1.68 221.84 11286 Yes 925 No 1975 12 7 10 130 1.08 262.43 11279 Yes 925 No 1975 12 7 11 131 0.86 281.69 12100 Yes 0 Yes 1975 12 7 12 132 0.75 276.56 11268 Yes 925 No 1975 12 7 13 133 0.41 260.60 11253 Yes 925 No 1975 12 7 14 134 0.37 250.00 11233 Yes 925 No 1975 12 7 15 135 0.28 231.53 11210 Yes 925 No 1975 12 7 16 136 0.25 216.03 11182 Yes 925 No 1975 12 7 17 137 0.25 200.98 11150 Yes 925 No 1975 12 7 18 138 0.38 193.00 11114 Yes 925 No 1975 12 7 19 139 0.58 197.45 11074 Yes 925 No 1975 12 7 20 140 0.34 190.38 11030 Yes 925 No 1975 12 7 21 141 0.30 183.88 10982 Yes 1439 No 1975 12 7 22 142 0.23 171.11 10930 Yes 1439 No 1975 12 7 23 143 6.21 158.92 10873 Yes 1439 No 1975 12 7 24 144 0.18 148.88 10813 Yes 1439 No 1975 12 8 1 145 0.18 140.68 10778 Yes 1439 No 1975 12 8 2 146 0.32 139.99 10737 Yes 1439 No 1975 12 8 3 147 0.40 143.98 10697 Yes 1439 No 1975 12 8 4 148 0.23 141.02 10658 Yes 1439 No 1975 12 8 5 149 0.32 142.61 10620 Yes 1439 No 1975 12 8 6 150 0.36 143.98 10583 Yes 1439 No 1975 12 8 7 151 0.30 143.75 10547 Yes 1439 No 1975 12 8 8 152 6.21 139.99 10513 Yes 1439 No 1975 12 8 9 153 0.18 133.95 10480 Yes 1739 No 1975 12 8 10 154 0.15 126.77 10447 Yes 1739 No 1975 12 8 11 155 0.14 120.50 10416 Yes 1739 No 1975 12 8 12 156 0.12 114.68 10387 Yes 1739 No 1975 12 8 13 157 0.12 109.11 10358 Yes 1739 No 1975 12 8 14 158 0.10 103.97 10330 Yes 1739 No 1975 12 8 15 159 0.10 99.07 10304 Yes 1739 No 197S 12 8 16 160 0.10 94.62 10278 Yes 1739 No 1975 12 8 17 161 0.09 90.63 10254 Yes 1739 No 1975 12 8 18 162 0.09 86.75 10231 Yes 1739 No 1975 12 8 19 163 0.09 83.45 10209 Yes 1739 No 1975 12 8 20 164 0.09 80.14 10189 Yes 1739 No 1975 12 8 21 165 0.07 77.29 10169 Yes 1739 No 1975 12 8 22 166 0.07 74.78 10151 Yes 1739 No 1975 12 8 23 167 0.07 72.39 10133 Yes 1739 No 1975 12 8 24 168 0.07 70.22 16117 Yes 1739 No 1975 12 9 1 169 0.06 68.40 10102 Yes 1739 No 1975 12 9 2 170 0.06 66.69 10087 Yes 1739 No 1975 12 9 3 171 0.06 64.98 10070 Yes 1739 No 1975 12 9 4 172 0.06 63.27 10052 Yes 1739 No 1975 12 9 5 173 0.06 61.90 10033 Yes 1739 No 1975 12 9 6 174 0.06 60.53 10013 Yes 1739 No 1975 12 9 7 175 0.06 59.17 9991 Yes 2150 No 1975 12 9 8 176 0.05 $8.03 9968 Yes 2150 No 1975 12 9 9 177 0.05 57.00 9944 Yes 2150 No 1975 12 9 10 178 0.05 55.97 9919 Yes 2150 No 1975 12 9 11 179 0.05 54.83 9892 Yes 2150 No 1975 12 9 12 180 0.05 53.81 9864 Yes 2150 No 1975 12 9 13 181 6.05 52.90 9835 Yes 2150 No 1975 12 9 14 182 0.05 51.98 9804 Yes 2150 No 1975 12 9 15 183 0.05 51.19 9773 Yes 2150 No 1975 12 9 16 184 0.05 50.39 9740 Yes 2150 No 1975 12 9 17 185 0.05 49.70 9706 Yes 2150 No 1975 12 9 18 186 0.16 50.27 9670 Yes 2150 No 1975 12 9 19 187 0.18 54.26 9634 Yes 2150 No 1975 12 9 20 188 0.21 58.94 9596 Yes 2150 No 1975 12 9 21 189 0.19 63.16 9556 Yes 2150 No 1975 12 9 22 190 0.23 69.31 9516 Yes 2150 No 1975 12 9 23 191 0.29 76.95 9474 Yes 2562 No 1975 12 9 24 192 0.31 84.59 9431 Yes 2562 No 1975 12 10 1 193 0.16 85.73 9409 Yes 2562 No 1975 12 10 2 194 0.13 86.30 9404 Yes 2562 No 1975 12 10 3 195 0.15 85.61 9394 Yes 2562 No 1975 12 10 4 196 0.11 82.54 9381 Yes 2562 No 1975 12 10 5 197 0.09 79.91 9364 Yes 2562 No 1975 12 16 6 198 0.07 76.95 9342 Yes 2562 No 1975 12 10 7 199 0.06 73.53 9316 Yes 2562 No 1975 12 10 8 280 0.06 70.34 9286 Yes 2562 No 1975 12 10 9 201 0.06 67.37 9252 Yes 2562 No 1975 12 10 10 202 0.05 64.52 9214 Yes 2562 No 1975 12 10 11 203 0.05 62.13 9171 Yes 2562 No 1975 12 10 12 264 0.05. 59.51 9124 Yes 2562 No 1975 12 10 13 205 0.05 57.34 9074 Yes 2562 No 1975 12 10 14 206 0.05 $5.40 9019 Yes 2562 No 1975 12 10 15 207 0.04 53.24 8959 No 1975 12 10 16 208 0.04 51.41 8896 No 1975 12 10 17 209 0.04 49.70 8829 No 1975 12 10 18 210 0.04 48.22 8757 No 1975 12 10 19 211 0.04 46.85 8681 No 1975 12 10 20 212 0.04 45.71 $601 No 1975 12 10 21 213 0.04 44.80 8517 No 1975 12 10 22 214 0.04 44.06 8429 No 1975 12 10 23 215 0.04 43.21 8336 No 1975 12 10 24 216 0.04 42.52 8239 No CITY OF RENTON MEMORANDUM DATE: January 15, 1992 TO: Gregg Zimmerman VIA: P uick Anderson FROM: �Randall Parsons SUBJECT: REVIEW OF METRO TREATMENT PLANT APPLICATION FOR STORMWATER CODE MODIFICATION - COSTS/AGREEMENT I have reviewed the proposed new agreement forwarded to me by Paul Forsander with regard to the $5,500 budget for review of the Stormwater code modifications and support calculations and administration of the review/approval process. I estimate that this task will require up to approximately 40 hours of my and my staff's time. Estimated at $30.00 per hour (salary and benefits at 15%) the total would be approximately $1 ,200.00. The remaining budget of $4,300, 1 expect would be expended by you and your staff in review of the construction plans for Metro's proposed stormwater pump station, wetponds/wetlands enhancement and conveyance system improvements related to and including the new stormwater outfalls to the P-1 channel system (following Metro's environmental review of this concept). I recommend that you verify your comfort level with the $4,300 budget for this work. Please call me at X-5548 if you have any questions. D:92-036:RLP:ps rCW2 rem CITY OF RENTON MEMORANDUM DATE: January 14, 1992 TO: Jim Hanson Don Erickson Gregg Zimmerman Randall Parsons FROM: Paul Forsander SUBJECT: New City/Metro Agreement for City Review Costs for Metro Treatment Plant. The agreement between Metro and the City dated 10 May 1991 has now expired because costs have exceeded the $30,000 maximum under this agreement. We have currently billed approximately $1500 beyond the agreement. Metro cannot reimburse the City for these and any future costs without a new agreement. According to Joe Fernandes, Metro's Project Manager, the existing agreement cannot be amended beyond the$30,000 maximum,thus a new agreement is required. 1 have drafted ai new agreement, schedule and budget for your review. Note: the new agreement cannot exceed $30,000. 1 will be meeting with Joe Fernandes for lunch on Friday, January 17th to discuss the draft agreement. Please get back to me by Thursday with your comments. Thanks. METRO 1. O DRAFT Agreement between Metro and the City of Renton Date 1992 Renton Treatment Plant Enlargement III Page 1 An Agreement between the City of Renton and the Municipality of Metropolitan Seattle for implementation of the Regional Treatment Plant in Renton - Phase ltl Enlargement for coordination of the storm water, building and construction permit reviews relating to the site preparation and perimeter landscaping contract. DATE: 1992 The purpose of this Agreement is to continue the process which was originally defined by the 10 May 1991 Agreement between Metro and the City for coordination and the Implementation of the Regional Treatment Plant Enlargement III in Renton during the City reviews of: the storm water system, building and construction permits relating to Metro's Site Preparation and Perimeter Landscaping contract. This agreement is necessary because the 10 May 1991 agreement did not anticipate the scope or cost of the permit reviews for the storm water.system or revisions to the Site Preparation and Perimeter Landscaping Contract resulting from the Hearing Examiner's Site Plan Approval decision. The City and Metro recognize that this project is complex and requires extraordinary and expeditious review services by City staff. It is also recognized that Metro needs to reimburse the City for review services during the permit review for the Site Preparation and Perimeter Landscaping Contract. The City and Metro have the authority and desire to enter into this Agreement and find it to be in the public interest. The overall responsibility for managing this Agreement shall be assigned to Metro's Technical Services Director and the City Administrator of the Planning/Building/Public Works Department. As defined in the Memorandum of Agreement (CAG-060-91) between Metro and the City, the Metro Project Manager shall have responsibility for the project for Metro, and the City Project Manager shall have responsibility for the City. The City shall use its best efforts to coordinate and conduct any necessary reviews and process any applicable permits and approvals by City departments simultaneously and promptly and consistent with the revised schedule mutually agreed to by the City and Metro (Exhibit A), and subject to the availability of Metro's plans and designs. The City and Metro shall work cooperatively to develop a process for estimating plan review costs. Metro will pay those certain fees that comprise reasonable and direct costs necessary to compensate the City for staff costs for coordination, plan review and other services directly related to the project. The eligible categories of costs and an estimate are listed in Exhibit B. In order to ensure timely payment for the review and processing of permits for the project, the City shall, after the effective date of this Agreement, provide Metro with an invoice on a monthly basis. Metro shall METROAGR.DOC/PF/DISK 2 DRAFT Agreement between Metro and the City of Renton Date 1992 Renton Treatment Plant Enlargement III Page 2 process the Invoices promptly and shall make payment to the City within 45 days of receipt of the invoice, assuming all backup information is provided with the invoice. Disputes shall be resolved as outlined in the Memorandum of Agreement between Metro and the City. Each party agrees to indemnity, defend and hold the other party harmless from all claims and lawsuits arising by reason of the parry's negligent acts or omissions performed pursuant to this agreement. Either party may terminate this Agreement by giving not less than thirty days written notice to the other party. Each party's obligations under this agreement shall continue until the effective date of termination. Finally, this Agreement shall take effect when both municipalities hereto have executed this document. IN WITNESS THEREOF, the municipalities have executed this Agreement as of the date first above written. Approved as to Form: MUNICIPALITY OF METROPOLITAN SEATTLE (METRO) Administrative Legal Counsel Richard. K. Sandaas Executive Director ATTEST: THE CITY OF RENTON City Legal Council By Earl Clymer Mayor METROAGR.DGC/PF/DISK 2 DRAFT Agreement between Metro and the City of Renton Date 1992 Renton Treatment Plant Enlargement If Page 3 SCHEDULE TO BE DEVELOPED BY FERNANDES, FORSANDER AND PARSONS EXHIBIT A RENTON TREATMENT PLANT ENLARGEMENT III REVISED PROJECT SCHEDULE Date Activity January 1992 Complete Storm Water System Design/Calculations. February 1992 Complete City review of storm water system design. March 1992 Issue storm water code modification/Issue construction permits. ME CAGR.DOO/PF/DISK2 DRAFT Agreement between Metro and the City of Renton Date 1992 Renton Treatment Plant Enlargement III Page 4 EXHIBIT B RENTON TREATMENT PLANT ENLARGEMENT III ELIGILBE CATEGORIES OF COST Category Cost 1. Review Construction Plans/Calculations for site utilities for Site Preparation $3,000.00 (Building) Permits E Review storm water system design/calculations for permits and request for $5,500.00 variance/modification from City Storm Water Ordinance/King County Surface Water Design Manual. 3. Review revised Perimeter landscaping Plans and revised perimeter/shoreline $3,500.00 trail per Site Plan Approval conditions required in the July 1991 Hearing Examiner decision. 4. Review revised site utility plans and site plan for addition of on-site portions $3,550.00 of the Interurban Interceptor and Alld Transfer Line. 5. Coordinate Program and Design review and Shoreline Permit for Cascade $2,000.00 Siphon Footbridge. Coordinate with WSDOT. 6. Coordinate planning/environmental and permit review for Cedar River $3,500.00 Interceptor. 7. Coordinate environmental review process with Metro for May Valley $5,500.00 Interceptor 8. Project Management/Administration. Preparation of annual reports and $2,650.00 maintenance of on going communication and coordination with Metro's Project Manager TOTAL $29,200.00 NOTE: The above figures are estimates and the actual amounts expended may vary, These amounds are based on a City billing rate of $75.00 per hour wich includes clerical support and overhead. MFMAGR.D00/PF/DISK2 "'METRO Municipality of Metropolitan Seattle Exchange Building • 821 Second Ave. • Seattle, WA 98104-1598 December 19, 1991 p�0 '� 0 1991 c gt Dertng DeP Mr. Franchot Fenske, Associate D R. W. Beck and Associates Fourth and Blanchard Building, Suite 600 2101 Fourth Avenue CS/M03-90 Seattle, Washington 98121 -2375 10-09/0028 Notice to Proceed - Review of Storm Water Diversion at the Regional Treatment Plant at Renton Dear Mr. Fenske: Effective December 23, 1991 , you are hereby issued Notice to Proceed for the work as identified in the attached scope of work. All work should be completed no later than January 31 , 1992. The maximum amount authorized under this contract is $8,971 .00. A copy of the executed agreement will be mailed to you under separate cover. If you have any questions please contact me at 684-2423. Very truly yours, J vIe- Joe Fernandes, Manager Treatment Plant Enlargement in Renton JF:em cc: Randall Parsons, City of Renton f Scope of Work Review of Storm Water Diversion at the Metro Treatment Plant in Renton The following scope of work relates to the review of a proposed storm water diversion from the Metro treatment plant site to Springbrook Creek. The proposed diversion is a part of the Metro treatment plant expansion project and would consist of collecting onsite storm water runoff that now discharges to the Green River and diverting it to Springbrook Creek at a location upstream of the Springbrook Creek Crossing of the SW 7th Avenue bridge . The purpose of this work shall be to estimate the increase in runoff volume received by the Springbrook Creek/Black River Pump Station (BRPS) resulting from the proposed diversion during a specific flood event simulation. The specific flood event simulation is based upon work performed by Northwest Hydraulic Consultants for the City of Renton and consists of the local 100-year flood control storage event under current land use conditions in coincidence with high Green River flows . The scope of work is divided into two tasks . The first tasks consists of using a simplified method (hydrologic modeling only) to estimate the additional storage volume required in the system as a result of the diversion. Task 2 includes a more accurate method (hydrologic and hydraulic modeling) of estimating the additional storage volume required in the system. Based upon the result of the simplified method, the City of Renton shall determine whether to proceed with Task 2 . To assist the Consultant in the performance of the work, Metro will provide the following information: - Total area of Metro site proposed for diversion - Percentages of impervious and pervious surfaces of contributing area - Average soil and cover description for the con- tributing pervious area - Time of concentration for entire site - Map of the proposed drainage system including description of the conveyance system and diversion showing preliminary sizes, lengths and slopes Task 1 This task will include developing a runoff hydrograph for the Metro site using the HSPF computer model. The work will be performed by Northwest Hydraulic Consultants (NHC) . The runoff hydrograph would reflect post developed Metro site for the 100-year flood control storage event in coincidence with high Green River flow (i.e . , 1975 Green River event) . A comparison of the Green River flow hydrograph, Springbrook Creek hydrograph, and the Metro discharge hydrograph will then be made to identify the Metro outflows during the time at which the pump station discharges are . restricted causing the forebay to store water. The BRPS must reduce pump discharges based upon the Green River flow at Auburn in compliance with the Green River Management Agreement . This will be done by first identifying the time period during the specified event in which the BRPS discharges must be restricted below the Springbrook inflow rates (i.e. the forebay is filling) . During this time period, it will be assumed that Metro' s discharge to the Green River will not function due to high Green River elevations . An estimate of the runoff volume from Metro site during this same time period can then be made. Using this calculated runoff volume, an estimate of the increase water surface elevation in the BRPS forebay will be made . The calculations will be summarized in a technical memorandum by NHC. NHC would also attend one meeting to discuss the results of the analysis . Tas_k_2 This task would include making a revision to the East Side HSPF hydrologic model and the East Side FEQ computer model to estimate the increase in water surface elevation at the BRPS forebay resulting from the diversion. Two runs with each model will be made to reflect the local current land use condition 100-year in coincidence with high Green River flow (i.e. , 1975 Green River event) . The first simulation would assume that the Metro Site does not contribute to the East Side System. The second simulation would assume that the Metro site is fully developed and flows are diverted to the East Side system. The simulation results would be reviewed to determine the additional storage volume that would accumulate at the BRPS and the increase in water surface elevation corresponding to the Metro diversion. For this simulation, it will be assumed that Metro' s discharge to the Green River cannot function due to high Green River elevations . The calculations will be summarized in a technical memorandum. The Consultant would also attend one meeting to discuss the results of the analysis . a rrt + c� FLF FrancholI—Feaske CITY OF RENTON MSG Mike Giseburt FASYSIDE GREEN RIVER WATERSHED PLAN SEC secretarial `D December 4, 1991 NI fC Northwest Hydraulic Consultants to 1KA Linsley Kreager Associates Metro Drainage Review W m c> z RW.BECK RWB RWB RWB SUBCONSULTANI o FLF MSG SEC total expenses labor cost NliC L.KA Task No.Description $35.02 $21.23 $10.38 hours m I I4SPF modeling of Metro Site to estimate 4 21 5 30 $10 $638 $2,205 runoff volume directed to BRPS forcbay for 100year event(storage) *� x z c� 1 30 4 35 $20 S713 $1.,995 $756 N 0 2 HSPF/FEO modeling of Metro Site to]sdmate rn runoff volume directed to BRPS forcbay for 100 year event(storage) P —------------------- m --- rn N Task 1 Task 2 TOW Cost Summary Direct Salary S638 S713 $1,351 Overhead(@ 1.681%) S1,072 SI 1,_99 SZZ71 Subtotal $1,710 $1,913 $3,623 Profit(@ 100) $171 $191 $362 Ecpetrm $10 320 $30 $4,956 Subconsulants $2205 $2751 0 N Total �,O9b R.W. BECK1 �r AND ASSOCIATES Fourth and Blanchard Building,Suite 600■2101 Fourth Avenue■Seattle,Washington 98121.2375■USA l I(+ 9 v Telephone(206)441.7500■Fax(206)441-4962 Telex 4990402 BECKSEA WW-0000-BC-CA December 2, 1991 Mr. Joe Fernandes, Manager Renton Expansion, METRO n Municipality of Metropolitan Seattle V 821 Second Avenue, M.S. 107 Seattle, Washington 98104-1598 C17 OF RENTON Engir:eering Dept, Dear Joe: Subject: Drainage Review for Renton As we discussed on November 27, 1991, we agreed that our costs would include a 10% profit allowance and we would not include a 5% mark-up on our subconsultant Northwest Hydraulics Consultants. We have revised our scope of work and the payment provision to reflect our agreement with you and we have enclosed a copy for your review and comments. In addition, we discussed the idea of the three parties involved in the project getting together when we have concluded our initial analysis to discuss the results and to decide if there is a need to continue with task 2 of the analysis. At this point, we are all hopeful that the second part of the analysis will not be required. We understand that Metro will prepare a purchase order directly with our Firm for this work and that we can expect a notice to proceed in the near future. FLF.077 Boston,MA•Columbus,NE•Denver,CO•IndunapoI6,IN•Minneapolis,MN Nashville,TN•Orlando,FL•Phoenix,AZ•Sacramento,CA•Seatde,WA Mr. Joe Fernandes Renton Expansion 2 December 2, 1991 If you should have further questions, please call me at 727-4596. Very truly yours, R. BECK AND ASSOCIATES Franchot L. Fenske Associate FLF:cs Enclosure c: Randall Parsons Ron Straka FLF.077 R.W.BECK AND ASS IAIES , . CITY OF RENTON Hearing Examiner — Earl Clymer, Mayor Fred J.Kaufman November 26, 1991 n r 1 � 1 Metro 1`,91 Gerrie Jackson J 821 Second Avenue I i=NTGN Seattle, WA 98104 Engineering Dept, Re: File No. V-040-91 Dear Ms. Jackson: The Examiner' s Report regarding the above referenced application, which was published October 14 , 1991, has not been appealed within the extended period of November 25, 1991, established by my November 5, 1991 letter to Gregory Bush. Therefore, this matter is considered final and is being transmitted to the City Clerk this date for filing. Please feel free to contact this office in writing if further assistance or information is required. Sincerely, 4�� FRED J. KA FMAN HEARING EXAMINER FJK:wmb cc/ City Clerk Waste Water Division Gregory Bush Parties of Record 200 Mill Avenue South - Renton, Washington 98055 - (206) 235-2593 ka d f� V-OYO-`l •;'s CITY OF RENTON Hearing Examiner Earl Clymer, Mayor Fred J. Kaufman November 5, 1991 fJ0�1 G 19'J1 � Gregory Bush OF RENTON Manager of Environmental Compliance t Metro Engineering Dept. Exchange Building, 821 Second,Avenue Seattle, WA 98104-1598 Dear Mr. Bush: I have reviewed your letter of October 28, 1991 requesting reconsideration of the decision to deny a variance to discharge stormwater to the P-1 channel and to utilize a pump in the stormwater conveyance system. In conjunction with this review this office has also reviewed a memorandum from the Public Works Department addressing some of these same issues. I believe that the best approach to handling this matter is to first explain that variances are not available unless all of the criteria enumerated for granting a variance are satisfied. An applicant either meets all of the conditions 'enumerated or the variance is denied. The biggest and most frequent obstacle to variance relief is the absence of a true physical constraint that actually would impede reasonable development of a site. That is a major misunderstanding that exists for applicants for variance relief. One does not grant a variance because the public interest will not suffer nor because it is more economical to do something another way nor because of a potential conflict with future land use. In order to even be considered, a site must have some physical circumstance, usually defined as some topographical or geological constraint, that would deprive the applicant of reasonable use of the site. Again, this is a general misunderstanding. It does not matter that some possible public benefit may result from granting a variance if the physical limitation is absent. It does not matter what alternatives or safeguards an applicant proposes to substitute for the ordinary requirements. Those arwnot at issue until the main criteria have been satisfied. The future use of land, whether owned by Metro or some other entity is not a reason to grant a variance. Everyone wants to make judicious use of land. Land is, admittedly, for Metro and for others a limited commodity. That does not justify variance relief. Nor is anyone questioning Metro's corporate citizenship. The fact that Metro is prepared to emphasize maintenance, has or can provide 24-hour monitoring, etc., does not offset its failure to demonstrate the physical limitations of the site. In addition, Metro's unique stature, status, or characteristics cannot be substituted for the site's existing, actual, physical constraints. Metro cannot be singled out for special treatment absent the appropriate physical constraint. It is a simple matter but one widely misunderstood by most variance applicants. Before going further, this office did not intend to limit Metro's interim use of the existing facility and its non-standard (in terms of the current requirements) use of the pump and effluent transfer system. As an interim proposition, the use of the existing facility is appropriate while the system is brought up to current standards. The language you quoted stated: 200 Mill Avenue South - Renton, Washington 98055 - (206) 235-2593 Mr. Goegory Bush November 5, 1991 2 The variance to permit interim discharge to the treatment plant's sanitary sewerage stream is appropriate since an alternative storm water disposal system will be necessary until a more permanent system is constructed. That language was intended to authorize an interim, as opposed to a permanent, solution. This office intended to limit the determination of the pump variance to the permanent facilities that Metro proposes to meet the city's current stormwater requirements. Metro suggests that the storage capacity required under the code would penalize Metro by requiring additional expenses and possibly land area for the improvements. The additional storage capacity required under a "pump" scenario does not unduly penalize Metro. It is a code requirement if a pump is used in the conveyance system. The decision has not denied Metro the right or ability to utilize the existing system. The decision only determined that the existing system must be augmented with additional storage capacity`as required by code. Again, Metro's justification enumerated on Page 8 of its request cannot substitute for, nor negate, the absence of true limitations. The additional storage capacity criterion is specifically required to permit the use of a pump system. In this case, there is no need to determine whether or not this office can vary a "storage capacity" precondition required to grant the principal pump variance. This office has not been provided with any basis which clearly specifies the constraint, other than some vague, future expansion plans, for granting a variance from that requirement. Frankly, variances are also not generally available to those who create their own hardship or in this case plan on creating a hardship. The applicant has failed to demonstrate any existing site constraints that justify this variance. If a variance were available to Metro for the reasons outlined - future expansion plans or economic considerations or pre-existing physical improvements - then a variance would be available to everyone and there would be no criteria to uphold. A precedent would have been created that a variance would be available based on economic considerations or future building plans. Those really do not demonstrate the necessary "physical circumstances" required for variance relief. Those are no more limiting physical circumstances than buying a lot which is too small to support the development an applicant wants and then claiming insufficient lot size is a physical hardship that can simply be overcome by then applying for a variance to overcome 'onerous" setback conditions. A variance should not be available in either circumstance without more. The variance from the additional criteria that permits a pump was appropriately denied. As for reconsidering the determination on the variance to release stormwater to the P-1 channel, this office has determined that the variance was appropriately denied. There is insufficient justification to reopen the issue for reconsideration under either the applicant's request or staff's suggestion that the appropriate capacity study will be accomplished in the near future. Section 4-8-15 provides that reconsideration is not available for the introduction of information that could have reasonably been available at the public hearing. The Storm Drainage Ordinance is quite clear that "down stream capacity" is to be considered before granting a variance. While the information was not available to reach a decision in this matter, it should have been. It was the applicant's responsibility to produce the information prior to or contemporaneous with the Public Hearing. Since the information should have been submitted by the applicant and was not, the request for reconsideration is inappropriate. In conclusion, this office has not found sufficient reasons to modify the decision, although, it appreciates Metro's providing the opportunity to clarify the issue of whether the existing facilities, including the pump, may be used on an interim basis. The facilities and pump may be so used. Mr. Gregory Bush November 5, 1991 3 If this determination is considered unsatisfactory, it may be appealed to Superior Court not later than November 25, 1991. If this office can be of further assistance, please feel free to write. -Z41`4� FRED J. KAUFMAN HEARING EXAMINER FJK:wmb cc/ Gerrie Jackson, Metro Louise Kulzer, Metro Warren Uhte, Brown & Caldwell Rick Butler, Brown & Caldwell Randall Parsons, Storm & Wastewater Utility Engineering Suprv. Mayor Earl Clymer Lynn A. Guttmann, Administrator, Planning/Bldg/Public Works Dept. Other Parties of Record PLANNING/ BUILDING/ PUBLIC WORKS DEPARTMENT ��\\ `t y MUNICIPAL BUILDING 200 MILL AVE. SO. RENTON, WASH. 98055 v� 0� 0 UTILITY SYSTEMS DIVISION - 235-2631 0 TRANSPORTATION SYSTEMS DIVISION - 235-2620 TO: DATE: JOB NO.: RE: ATTN: GENTLEMEN: WE ARE SENDING YOU o ATTACHED o UNDER SEPARATE COVER VIA THE FOLLOWING ITEMS: o SHOP DRAWINGS o PRINTS o REPRODUCIBLE PLANS o SPECIFICATIONS o COPY OF LETTER o COPIES DATE NUMBER DESCRIPTION AND REMARKS THESE ARE TRANSMITTED AS CHECKED BELOW: o FOR APPROVAL o APPROVED AS SUBMITTED o RESUBMIT COPIES FOR APPROVAL o FOR YOUR USE o APPROVED AS NOTED o SUBMIT COPIES FOR DISTRIBUTION o AS REQUESTED o RETURNED FOR CORRECTIONS o RETURN CORRECTED PRINTS o FOR REVIEW AND COMMENT o o PRINTS RETURNED AFTER LOAN TO US COPIES TO: SIGNED TITLE IF ENCLOSURES ARE NOT AS NOTED, KINDLY NOTIFY US AT ONCE K.W. t tu& ►' R AND ASSOCIATES SEATTLE COMPLEX Facsimile Transmission Fourth and Blanchard _ t�A Pky50,y S Building, Suite 600 To: — 2101 Fourth Avenue — Seattle, Washington 7 S - Z s '{ 98121-2375 Phone (fax): Tel: (206) 441-7500 �W _ � Sri _ i 5 A- _v*-;4 Fox: (206) 441-4962 W.0.: Telex: 4990402 BECKSEA Date: -- If this message is _- incomplete or illegible, please calf F (206) 727-4551. Message consists of 3 pages, including this cover sheet. Regarding: JGO E- O i— �o,GFc� /o go�i IO 'd Z9DIVV 90e 'ON XV. S31VIOOSSV QNd N28 M8 60:81 3ni 16-6d-100 City of Renton Metro Treatment Plant Expansion Project Date: 1029/91 Subject: Scope of Work Review of Storm Water Diversion Metro Treatment Plan Expansion General The following scope of work will be provided to Brown and Caldwell Consultants by R. W. Beck and Associates (herein referred to as Consultant) , relating to the review of a proposed storm water diversion from the Metro treatment plant site to Springbrook Creek. The proposed diversion is a part of the Metro treatment plant expansion project and would consist of collecting onsite storm water runoff that now discharges to the Green River and diverting it to Springbrook Creek at a location upstream of the Springbrook Creek Crossing of the SW 7th Avenue bridge. The purpose of this work shall be to estimate the increase in runoff volume received by the Springbrook Creek/Black River Pump Station (BRPS) resulting from the proposed diversion during a specific flood event simulation. The specific flood event simulation is based upon work performed by Northwest Hydraulic Consultants for the City of Renton and consists of the local 100- year flood control storage event under current land use conditions in coincidence with high Green River flows. The scope of work is divided into two tasks . The first tasks consists of using a simplified method (hydrologic modeling only) to estimate the additional storage volume required in the system as a result of the diversion. Task 2 includes a more accurate method (hydrologic and hydraulic modeling) of estimating the additional storage volume required in the system. Based upon the result of the simplified method, the City of Renton shall determine whether to proceed with Task 2 . To assist the Consultant in the performance of the work, Brown and Caldwell will provide the following information: Total area of metro site proposed for diversion percentages of impervious and pervious surfaces of contributing area Average Soil and cover description for the contributing pervious area Time of concentration for entire site Map of the proposed drainage system including description of the conveyance system and diversion showing preliminary sizes, lengths and slopes. Task 1 ZO 'd Z9W6 V 9H 'ON Hd3 S31VIOOSSV ON8 A038 M8 b0,81 3AI I6-H-100 This task will include developing a runoff hydrograph for the Metro site using the HSPF computer model. The work will be performed by Northwest Hydraulic Consultants (1411C) . The runoff hydrograph would reflect post developed Metro site for the 100-year flood control storage event in coincidence with high Green River flow (i.e. , 1975 Green River event) . A comparison of the Green River flow hydrograph, Springbrook Creek hydrograph, and the Metro discharge hydrograph will then be made to identify the Metro outflows during the time at which the pump station discharges are restricted causing the forebay to store water. The BRPS must reduce pump discharges based upon the Green River flow at Auburn in compliance with the Green River Management Agreement. This will be done by first identifying the time period during the specified event in which the BRPS discharges must be restricted below the springbrook inflow rates (i.e. the forebay is filling) . During this time period, it will be assumed that Metro's discharge to the Green River will not function due to high Green River elevations. An estimate of the runoff volume from Metro site during this same time period can then be made. Using this calculated runoff volume, an estimate of the increase water surface elevation in the BRPS forebay will be made. The calculations will be summarized in a technical memorandum by NHC. NHC would also attend one meeting to discuss the results of the analysis. Task 2 This task would include making a revision to the East Side HSPF hydrologic model and the East Side FEQ computer model to estimate the increase in water surface elevation at the BRPS forebay resulting from the diversion. Two runs with each model will be made to reflect the local current land use condition 100- year in coincidence with high Green River flow (i. e. , 1975 Green River event) . The first simulation would assume that the Metro Site does not contribute to the East Side System. The second simulation would assume that the Metro site is fully developed and flows are diverted to the East Side system. The simulation results would be reviewed to determine the additional storage volume that would accumulate at the BRPS and the increase in water surface elevation corresponding to the Metro diversion. For this simulation, it will be assumed that Metro 's discharge to the Green River cannot function due to high Green River elevations. The calculations will be summarized in a technical memorandum. The Consultant would also attend one meeting to discuss the results of the analysis . Payment The estimated cost for task 1 and task 2 is and respectively. The estimated cost is an allowance. The actual cost £0 'd Z96VM 9H 'ON XUA ShV10OSSd 0Nd N038 MN S0:9I 3RI I6-H-100 shall be based upon cost incurred on a time and materials basis. Coate for subconsultants work shall be marked up 5 percent. b0 'd Z9 H" 90E ON Kdd S31dI0OSSb aNd N038 M8 90:91 3Ni I6-62-i00 :;;: -m TRO Municipalify of Metropolitan Seattle Exchange Building • 821 Second Ave. • Seattle,WA 98104-1598 October 28 1991 (-ITYOFREN" RECENM OCT 2 81991 Fred Kaufman �usrouiERSERvae Hearing Examiner City of Renton 200 Mill Avenue So. Renton, WA 98053 Re: Metro Stormwater Variance (No. V-040-91) ; Request for Reconsideration Dear Mr. Kaufman: The Municipality of Metropolitan Seattle (Metro) hereby requests reconsideration of your October 14 , 1991 Report and Decision (Decision) , which denies in part Metro's request for variances to implement its proposed stormwater management program. Specifically, we request that you reconsider, or at least clarify, your decision denying a variance to discharge stormwater to the P-1 channel and to utilize a pump. DISCHARGE TO P-1 CHANNEL Metro requested variances from the requirement in the King County Surface Water Design Manual (Manual) regarding discharge at the natural location. We explained in the variance application that variances from this requirement were requested in part " [t]o allow permanent discharge of stormwater from the wetponds, and rare emergency relief flows, into the P-1 channel rather than to the Green River. " Application for Variance Pursuant to 4-22-16 (Sept. 16, 1991) ("Variance Application") , p. 3 . Downstream Capacity of P-1 Channel In Conclusion 2 of the Decision, you stated that the "capacity of downstream facilities" must be evaluated prior to issuance of such a variance and that it would be contrary to law to condition the variance to determine downstream capacity after the variance is approved. In Conclusion 12 , you stated with regard to the release of wetpond treated stormwater that the "absence of information on the downstream capacity of the P-1 system rules that out. " Decision, p. 7. Metro did, however, evaluate the downstream capacity of the P-1 channel for the Mr. Fred Kaufman October 28 , 1991 Page 2 discharge of up to 4 .5 cfs of treated stormwater [and emergency relief flows] . In the variance application, Metro stated [regarding the discharge of 4.5 cfs] : Preliminary modeling results show that flows in the P-1 channel at the forebay of the P-1 pumping plant will be approximately 789 cfs during a two-year storm event and 1518 cfs during a 100-year storm event. The 4.5 cfs of stormwater predicted to be contributed from Metro's stormwater facilities would result in an insignificant (about 0. 6%) increase during a two-year storm. In short, the downstream facilities of the P-1 channel offer sufficient capacity to accommodate Metro's stormwater flows. Variance Application, p. 5. Metro and its consultant concluded that the discharge from the site would not increase the peak flow in the P-1 channel by more than 0.6%, from 789 to 793.5 cfs, during the two-year storm event, and that this increase will not measurably impact the capacity of the P-1 channel, the storage capacity of the pump station forebay, or the available pumping capacity of the Black River pump station. We believe that this conclusion was and is reasonable and that no further analysis of downstream capacity for the two-year storm (4.5 cfs) was or is necessary or justified. We also believe, as noted below, that Renton staff concurred with the assessment. You mentioned in conclusion 2 that staff recommended that the applicant provide a detailed analysis of the downstream capacity of the P-1 channel system. It should be clarified that staff' s recommendation was limited to the discharge of emergency relief flows (i.e, during a 100-year storm event) . Staff did not recommend, nor suggest, in its report that discharge to the P-1 under normal circumstances (i.e. , the two-year storm event) required any further analysis. Regarding the discharge of emergency relief flows to the P-1 channel, we also concluded that stormwater from the site would not have a measurable effect on the downstream capacity of the P- 1 channel system. According to modeling results contained in the I The predicted two-year peak flow of 793. 5 cfs is well within the pumping capacity of the Black River pumping station (3000 cfs) during the two-year storm. Also, the corresponding P- 1 channel elevation (EL 102) during a two-year storm is below the maximum water surface elevation of the pump station forebay (EL 113) and well within the banks of the P-1 channel itself. Mr. Fred Kaufman October 28 , 1991 Page 3 Drainage Report (Brown & Caldwell, Sept. 16, 1991) ("Drainage Report") , a 100-year storm will produce a peak runoff of 22 cfs into Renton's stormwater sewer system. Drainage Report, p. 8 . Peak flows in the P-1 channel at the forebay of the Black River pumping plant will peak at approximately 1518 cfs. Variance Application, p. 5. If both peaks coincide--a conservative assumption--the peak flow with treatment plant stormwater would be 1540 cfs (a 1.5% increase) , which is below the capacity of the P-1 channel and pumping station. Stormwater at the site must go somewhere during an extreme flood event or else it will threaten plant operations. Our reasons for selecting the P-1 channel for discharge under such circumstances were stated previously. See Variance Application, pp. 5-6. We acknowledge that determining the capacity of the P-1 channel and forebay during a 100-year flood event is complex and depends on the level of the Green River and other variables. We agree that additional analysis of the downstream capacity of the P-1 channel during a 100-year storm should be performed, and we are currently working with Renton staff in this regard. Finally, we urge you to distinguish the discharge of up to 4 . 5 cfs of treated stormwater during an average two-year storm event from the discharge of emergency relief flows during extreme flooding. We understood your concern at the hearing to be limited to the latter. We believe that the request for a variance to discharge up to 4. 5 cfs of treated stormwater to the P-1 channel can be granted even if the discharge of emergency relief flows to the P-1 channel is denied. We therefore respectfully request that you reconsider your decision and allow discharge of up to 4 .5 cfs of treated stormwater and emergency relief flows to the P-1 channel, or at least allow just the discharge of 4 .5 cfs of treated stormwater. Factual Clarifications We also offer the following comments to clarify some of the information contained in the findings of the Decision regarding discharge of stormwater flows. Finding 11 states: The piping system is in place and served the existing plant. Under the then existing regulations, storm water was released into the Green River from this system. The applicant now proposes releasing the storm water, except for extraordinary flows, to the P-1 channel to avoid certain requirements and limitations on releasing storm water into the Green River. Mr. Fred Kaufman October 28, 1991 Page 4 Decision, p. 4 (emphasis added) . First, as we explained, our reasons for proposing to discharge treated stormwater to the P-1 channel are to (1) be more compatible with the proposed site location of the wetponds; (2) be more compatible with the historic natural drainage of the site; (3) preserve the opportunity for possible future wetlands enhancement; and (4) avoid the limitations established by the normally higher water surface elevation of the Green River than that of the P-1 channel during storm events. See e.g. , Variance Application, pp. 4-6. Second, although flows in excess of the first 4 . 5 cfs will continue to discharge to the Green River by gravity through the existing outfall, we proposed to discharge the "extraordinary flows" to the P-1 channel via two 30-inch relief sewers. Finding 14 states in part, "Storm water in excess of pump capacity will be released to the Green River under an agreement with the flood control agency. " Decision, p. 5. It was our understanding at the hearing, based on discussions with Renton staff, that no agreement is necessary to release stormwater flows in excess of 4 . 5 cfs to the Green River, except during a 100-year storm event. PUMP Metro requested a variance from the requirement in the Manual prohibiting the use of pump systems. A pump was included in Metro's proposed stormwater system to lift stormwater to the ground surface and then to convey the stormwater to the treatment plant during the interim period and to the wetpond facility once the wetponds are constructed. See Variance Application, pp. 8-9; Exhibit No. 3 . We also requested a variance from one of the conditions for granting a pump variance, which requires the construction of a large storage facility for the pump in case of pump failure. Variance Application, pp. 8-9. Use of Pump System According to conclusions 7 and 8, the pump system variance was denied because Metro did not demonstrate real physical constraints, undue hardship, and deprivation of "reasonable use,, of the site. Decision, p. 6. You also expressed concern about creating "undue precedent" that would then be available to most other developers. We believe these conclusions are in error. We offer the following points and urge your reconsideration. Metro has a public responsibility to manage and develop its land consistent with its mission of providing wastewater treatment to sewage flows within its jurisdiction. This does not Mr. Fred Kaufman October 28, 1991 Page 5 mean that Metro deserves preferential treatment over private developers when it applies for a variance. However, it means that Metro faces constraints that do not apply to private developers, and that it is legitimate for these constraints to inform your analysis of what constitutes "deprivation of reasonable use of property" and "undue hardship. " Metro must use its land for a particular purpose based on demand, unlike most developers who may choose what they want to do with their property and when they want to do it. Siting and permitting another wastewater facility in the vicinity is extremely difficult and unlikely, which means that Metro must make the best use of its existing site. Consequently, the remaining undeveloped land at the site is not "extra" but must be managed judiciously with an eye to the future. Under these circumstances, we believe a variance is appropriate to implement an equal or better stormwater system that takes advantage of the existing sewer system by using a pump. Strict compliance with the Manual will also create undue hardship for Metro. The time, effort, and expense involved to construct a new sewer system or a storage facility for a pumping station can be avoided without any detriment to the public welfare. A new sewer system is wasteful and duplicative given the existing network of underground piping at the site that could be utilized if a pump could be installed. Similarly, a large storage facility for a pumping station is redundant given all of the safeguards (described below) to protect against flooding in the proposed plan in case of pump failure. There is also a public interest element that we believe ought to be considered in this variance request. As a public agency, Metro has a responsibility to spend public funds wisely. Metro 's proposed stormwater system is fiscally responsible (while providing equal or better treatment of stormwater than required by the Manual) . The proposed pump system will allow Metro to maximize its use of existing facilities and thereby preserve valuable land for future wastewater treatment facilities, and will avoid large and unnecessary expenditures of public funds. As a result, Metro will better serve the general public who otherwise must absorb the cost, through sewer rates, associated with strict compliance with the Manual. We therefore urge that you reconsider your conclusions with respect to the proposed stormwater system' s consistency with the general variance criteria. We request that you approve the variance for the pump system (including the variance from the storage facility requirement) so that stormwater flows can be lifted from the existing outfall manhole to ground surface, then Mr. Fred Kaufman October 28, 1991 Page 6 conveyed to the wetponds (and, during the interim, to the treatment plant) . Pumping To Treatment Plant During Interim Metro's proposal to treat stormwater during the interim involves the use of a pump to convey stormwater to the treatment plant. We stated, "In the interim--while these facilities are being designed and constructed--the pump station will pump stormwater flows to the headworks of the wastewater plant for treatment and discharge to Puget Sound via the Effluent Transfer System (ETS) . " Variance Application, p. 3 . You recognized the necessity of this interim approach and agreed that a variance would be appropriate. You stated: The variance to permit interim discharge to the treatment plant 's sanitary sewerage stream is appropriate since an alternative storm water disposal system will be necessary until a more permanent system is constructed. Decision, p. 7. In Conclusion 4, however, you stated that your "office cannot vary the specific criteria necessary to permit a pump system in the storm drainage conveyance system. " Decision, p. 6. We believe that the Decision is ambiguous about whether or not Metro is allowed to use a pump during the interim to convey stormwater to the treatment plant. We understand that you have denied our variance request to use a pump to convey stormwater to the wetponds. Have you also denied our variance request to use a pump to convey stormwater to the treatment plant during the interim? The Decision does acknowledge that the variances requested in the application are inextricably linked and that granting some of the variances may not be of much consequence without the additional variances. This could mean that you were fully aware of the predicament created by approving the discharge of stormwater through the treatment plant during the interim but denying a vital link in the approach--the use of a pump to convey stormwater to the plant. on the other hand, if you did not realize that a pump is required for the interim approach, you may not have intended to foreclose this approach when you denied the use of a pump. The Decision does not appear to recognize that a pump is necessary during the interim to lift stormwater to ground surface and then to convey the stormwater to the treatment plant. For Mr. Fred Kaufman October 28 , 1991 Page 7 example, in Findings 13 and 14, you only referred to pumping with respect to conveying stormwater to the wetponds. Also, in Finding 9, where you describe the interim approach, there is no mention of our request for a variance to pump flows to the treatment plant during the interim. You stated in part: While the plant is being expanded and storm water facilities are under construction they proposed that as an interim measure storm water will be collected and mixed with the sanitary sewage, treated in the plant and discharged through the effluent transfer system (a tunnel to Puget Sound) to Puget Sound. Since this discharge would not be at the natural location the applicant has requested a variance. . . . Decision, p. 4 . We wonder whether you assumed that stormwater would be "collected and mixed" without the use of a pump or that we were not requesting a variance to pump stormwater to the treatment plant during the interim. The pump is essential to provide for treatment of stormwater during the interim while permanent stormwater facilities are constructed. Interim pumping would be necessary even if Metro could design a stormwater system that eventually met every requirement in the Manual. We therefore urge you to clarify that Metro is allowed to use a pump during the interim to convey flows to the treatment plant. Dual Pumps/Storage Facility In Conclusion 4, you stated: The request to issue a variance from the specially enumerated requirements for approving a variance from the "pump" criteria is unwarranted. The applicant proposes using dual pumps to move water from the initial detention system to the wetponds. The applicant suggests the dual pumps should adequately replace the storage facility which is required to hold 25% of the runoff. The dual pumps the applicant suggests should take the place of the 25% capacity are already required if a pump is used and so is the 25% capacity. It is not a vice/versa situation. If a pump is used it must be a dual pump and the 25% capacity must be supplied. The applicant is piling variances upon variances leaving little of the code provisions that are not circumvented. Mr. Fred Kaufman October 28 , 1991 Page 8 Decision, p. 6. We believe there may have been some misunderstanding about our proposal with respect to the dual pumps and their relationship to the 25% capacity requirement. Metro agrees that dual pumps and the 25% capacity requirement are separate and distinct preconditions for obtaining a pump variance. We were not suggesting that using dual pumps alone would satisfy the 25% capacity requirement. Instead, Metro suggested that dual pumps, together with other measures, will provide similar or better protection in case of pump failure. In addition to dual pumps, we have incorporated the following safeguards to protect surrounding property from flooding in case of an emergency situation such as a power outage or a mechanical failure: * Gravity overflow in excess of pump capacity to the P-1 channel (via the proposed 30-inch relief sewers) during extreme storm events. * Gravity overflow in excess of pump capacity to the Green River (via the existing outfall diffuser) during non-extreme storm events. * A wetpit pump station and stormwater sewers with a storage volume of 180, 000 gallons, which provides about half of the volume required by the Manual according to modeling results (i.e. , about 12 .5% capacity) . * 24 hours per day monitoring, operation, and maintenance staff on-site. * An emergency power supply and dual power feeds to the treatment plant. * External controls as well as external alarms. * Flap gates to prohibit the inflow of the Green River into the pump station during extreme flood events. See Variance Application, p. 9; Drainage Report, pp. 3-5. We believe these measures provide assurance of equal or better protection than constructing a large wetpit around the pump.2 We were not attempting to pile variances on top of each 2 It should be noted that a large wetpit may be appropriate for most pump stations, which, unlike the one proposed by Metro, are located downstream in remote areas at the lowest point of the gravity drain system. Metro's situation is somewhat unique because Mr. Fred Kaufman October 28, 1991 Page 9 other or avoid complying with stormwater requirements. We were simply proposing an alternative, yet equally protective, way to satisfy these requirements, given the unnecessary hardship created by strict compliance with the Manual, while taking advantage of the special circumstances available at Metro' s treatment plant at Renton. CONCLUSION For the foregoing reasons, we respectfully request that you reconsider your decision denying a variance to discharge stormwater to the P-1 channel and to utilize a pump. Very truly yours, Gregory Bush Manager of Environmental Compliance, Right of Way and Properties relief can be provided without storage via gravity drains to the Green River and the proposed relief sewers to the P-1 channel and, in addition to the other safeguards, because the pump station is located on-site where experienced operation and maintenance staff are available at all times. CITY OF RENTON MEMORANDUM DATE: October 28, 1991 TO: Fred Kaufman, Hearing Examiner FROM: �1�annrtiin / ann, Administrator ///��� ilding/Public Works Department STAFF CONTACT: ( Randall Parsons, Stormwater and Wastewater Utility Engineering Supervisor SUBJECT: �If yl METRO Treatment Plant Expansion Proposed Variance from Storm Drainage Code Requirements The Department's Stormwater Utility has reviewed your Report and Decision of October 14, 1991 regarding the proposed variance and requests that you reconsider your decision with regards to Conclusion 4. It is the Department's position that your office can vary the specific criteria necessary to permit a pump system in the storm drainage conveyance as is the case for any requirements, methods of analysis or design standards, if so specifically requested (as it was on page 9 of the application). Randall Parsons,the City's Stormwater and Wastewater Utility Engineering Supervisor, who was the project manager for King County in developing the King County Surface Water Design Manual, was responsible for authoring the Pump System"minimum conditions"contained in Core Requirement No. 4: Conveyance Systems, and supports METRO's justification for allowing the reduced wetwell size. He has noted that the "minimum condition' number 3, which requires a pump system to be sized to hold 25 % of the total volume of runoff for the developed tributary drainage area for the 2-year, 24-hour duration design storm event was intended to provide a factor of safety, should the pump system fail, to allow an opportunity for emergency action to be implemented prior to flood damage occurring. This is because in most situations a stormwater pump is proposed to address the quantity of runoff and is used to pump water up from a low point on a project site. In this case,where the project site has an existing gravity outfall to the dispersion system in the Green River, the pump system is only being used to meet (and exceed by threefold)the water quality requirements. It is the Stormwater Utility's understanding that without the ability to pump the stormwater into the treatment plant on an interim basis (as approved in your Decision 1)that it is either physically impossible (due to elevation difference) or it would be prohibitively costly (would require construction of a dual stormwater pipe conveyance system). While this was understood by Randall in his review of the technical materials, it is likely that it should have been stated more clearly in the variance application materials. We understand that METRO will be providing further clarification of this issue in their request for your reconsideration. In addition, I have received a letter from METRO noting that they will be proceeding with the study by the City's consultant's performing the Eastside Green River Watershed Plan, R. W. Beck and Associates, to analyze impacts on the P-1 Channel resulting from the discharge of stormwater li fm the METRO Treatment Plant. The results from this study will be used to address this aspect of the variance from Core Requirement No. 1: Discharge at the Natural Location noted in your Conclusions 2 and 12. The Department, therefore, supports a continuance of your consideration of this aspect of the variance request for a period of up to 90 days to allow for this study to be completed and the results reported to you. METRO Treatment Plant Expansion Storm Drainage Code Variance Request October 27, 1991 Page 2of2 If you have any additional questions or require additional information or explanation, please call Randall at extension 5548. LG:RP:rp:METFRDRE.DOC cc Joe Fernandes,Manager,Treatment Plant Enlargement in Renton Dick Anderson,Utility Systems Division Manager Ron Straka,Stormwater Utility Civil Engineer Don Erickson,Zoning Administrator,Development and Planning Section Paul Forsander,Senior Planner,Development and Planning Section CONCURRENCE DATE Ib 2S I CITY OF RENTON NAME INITIAVDATE • MEMORANDUM i I DATE: October 28, 1991 TO: Fred Kaufman, Hearing Examiner FROM: Lynn Guttmann, Administrator Planning/Building/Public Works Department STAFF CONTACT: andall Parsons, Stormwater and Wastewater Utility Engineering Supervisor SUBJECT: �If yl METRO Treatment Plant Expansion Proposed Variance from Storm Drainage Code Requirements The Department's Stormwater Utility has reviewed your Report and Decision of October 14, 1991 regarding the proposed variance and requests that you reconsider your decision with regards to Conclusion 4. It is the Department's position that your office can vary the specific criteria necessary to permit a pump system in the storm drainage conveyance as is the case for any requirements, methods of analysis or design standards, if so specifically requested (as it was on page 9 of the application). Randall Parsons, the City's Stormwater and Wastewater Utility Engineering Supervisor, who was the project manager for King County in developing the King County Surface Water Design Manual, was responsible for authoring the Pump System "minimum conditions"contained in Core Requirement No. 4: Conveyance Systems, and supports METRO's justification for allowing the reduced wetwell size. He has noted that the "minimum condition" number 3, which requires a pump system to be sized to hold 25 % of the total volume of runoff for the developed tributary drainage area for the 2-year, 24-hour duration design storm event was intended to provide a factor of safety, should the pump system fail, to allow an opportunity for emergency action to be implemented prior to flood damage occurring. This is because in most situations a stormwater pump is proposed to address the quantity of runoff and is used to pump water up from a low point on a project site. In this case, where the project site has an existing gravity outfall to the dispersion system in the Green River,the pump system is only being used to meet (and exceed by threefold)the water quality requirements. It is the Stormwater Utility's understanding that without the ability to pump the stormwater into the treatment plant on an interim basis (as approved in your Decision 1)that it is either physically impossible (due to elevation difference) or it would be prohibitively costly (would require construction of a dual stormwater pipe conveyance system). While this was understood by Randall in his review of the technical materials, it is likely that it should have been stated more clearly in the variance application materials. We understand that METRO will be providing further clarification of this issue in their request for your reconsideration. In addition, I have received a letter from METRO noting that they will be proceeding with the study by the City's consultant's performing the Eastside Green River Watershed Plan, R.W. Beck and Associates, to analyze impacts on the P-1 Channel resulting from the discharge of stormwater tcfm the METRO Treatment Plant. The results from this study will be used to address this aspect of the variance from Core Requirement No. 1: Discharge at the Natural Location noted in your Conclusions 2 and 12. The Department, therefore, supports a continuance of your consideration of this aspect of the variance request for a period of up to 90 days to allow for this study to be completed and the results reported to you. METRO Treatment Plant Expansion Storm Drainage Code Variance Request October 27, 1991 Page 2 of 2 If you have any additional questions or require additional information or explanation, please call Randall at extension 5548, LG:RP:rp:METFRDRE.DQG -- - cc Joe DiFemandes� er ireet €ntarg8rvtsntfiA811ton ck Anderson �\ Ron StrakaoewMertiHl' � \� Don Erickson,-�enlgQ-AAmI IqQ-SNn11 Paul Forsander OF! rt- �t F METRO Municipality of Metropolitan Seattle Exchange Building • 821 Second Ave. • Seattle, WA 98104-1598 October 25, 1991 Ms. Lynn Guttman, Administrator 0J91 Planning/Building/Public Works OF RFNTON Renton Municipal Building Lnginecring Dept. 200 Mill Avenue South Renton, Washington 98055 Subject : Conduct study to analyze impacts on the P-1 Channel resulting from discharge of stormwater flows from the Metro Treatment Plant in Renton, Enlargement III. Dear Ms. Guttman: Referring to the Hearing Examiner's report and decision dated October 14, 1991 , Metro concurs to conduct a hydrologic/hydraulic analysis to analyze the potential impacts on the existing P-1 channel resulting from the stormwater discharge from the Metro Treatment Plant Enlargement III. In order to expedite the implementation of the study, we are requesting authorization from the City of Renton to negotiate the scope of work and cost of the study with R. W. Beck and Associates, the City's consultants. I have had discussions with Mr. Randall Parsons regarding the matter and he supports the approach. Also, before commencement of any work, the City of Renton Staff will have an opportunity to review and concur with the scope of work. If the intent of this letter meets with your approval, please sign the concurrence space below. Ms. Lynn Guttman Page 2 October 25, 1991 We appreciate your staffs cooperation in getting this study underway. Very truly yours, ice, ��-,r,.c..,� - s Joe Fernandes, Manager Treatment Plant Enlargement in Renton cc: Randall Parsons - City of Renton Paul Forsander - City of Renton Jack Warburton - Brown and Caldwell Concur x L7� Memo 5400 . 03/3010201 TO: File FROM: Rick Butler DATE: Oct. 23 , 1991 SUBJECT: Wet Well Requirements - Stormwater Pump Station Renton Enlargement III Based on the proposed stormwater pump station on-level of EL. 113 . 0 , a 10 , diameter wet pit with invert EL. 108 .0, and utilizing all storm sewers upto EL. 113 . 0, and higher assuming some headloss, for storage volume (except the sewers in the sludge dewatering and digestion area which are physically separated from gravity system by a force main) , 00 allons of storage are available with the current posed sewer system. ditiona�otal storage volume required = 14 0 lons) more ga ons of wet well storage are required according to the King Co. Manual to supply the required volume of 25% runoff from a 2-year 24-hour storm (2 inches) . This translates into 170 lineal feet of 12-foot diameter pipe or a tank 12 feet deep and 39 ' x 39 ' in plan. One solution is to replace the 30-inch storm sewer line tributary to the north of the outfall manhole. Replacing the 305 lineal foot section of sewer with a 10-foot diameter pipe will increase the storage volume by 168, 000 gallons of storage, which is more than adequate. A 9-foot pipe would only increase the storage volume by 134, 000 gallons . THE CITY 01: RENION - DEPARTMENT OF PLANNING/BuILDING/PUBLIC WORKS _ RENTON. WASHINGTON 98055 2189 PHONE 235-2631 FAX: 235-2541 FAX TRANSMITTAL DATE: FROM: �9x�� _ !'�stvSoirS Z77-Sq� SUBJECT: f�SG w 7 c a-nr 5lnQ f th:,,L mat -0 Number of pages excluding cover sheet: • October 14, 1991 OFFICE OF THE HEARING EXAMINER CITY OF RENTON REPORT AND DECISION APPLICANT: METRO all j 1, I991 File No.: V-040-91 CITY OF RENTON LOCATION: 1200 Monster Road S.W. En�(reermg Dept, Renton, WA SUMMARY OF REQUEST: Variance from requirements contained in Section 4-22-8 of the City Code: Drainage Plan Requirements and Methods of Analysis to allow expansion of the existing Metro Treatment Plant at Renton. The applicant has requested a variance from the following: Core Requirement #1: Discharge at natural location; Core Requirement #3: Runoff Control; Core Requirement #4: Conveyance System; and Core Requirement #5: Special Water Quality Controls. SUMMARY OF ACTION: Public Works recommended Approval with Conditions. PRELIMINARY REPORT: The staff report was received by the Examiner on September 24, 1991 PUBLIC HEARING: After reviewing the report, examining available information on file with the application, and field checking the property and surrounding area, the Examiner conducted a public hearing on the subject as follows: MINUTES The hearing was opened on October 1, 1991 at 9:00 A.M. in the Council Chambers of the Renton Municipal Building. Parties wishing to testify were affirmed by the Examiner. The following exhibits were entered into the record: Exhibit #1 - Yellow File containing application, proof of posting and publication and other documentation pertinent to this request. Exhibit #2 - Series of ponds Exhibit #3 - Chart of proposed storm water system Exhibit #4 - Map of piping system Exhibit #5 - Metro treatment plant site plan approval Exhibit #6 - Metro modified language, condition #1 & #2 The hearing opened with a presentation of the staff report by the Utility Engineering Supervisor, Randall Parsons. A review of his testimony follows. Mr. Parsons stated Metro has requested a variance from several requirements contained in Section 4-22- 8 of the City Storm and Surface Water Drainage Code: Drainage Plan Requirements and Methods of Analysis, for the interim and permanent storm drainage facilities needed for expansion of the Metro 'r- ot:n.q-. Rant at Renton. The-.e :_.,wire-nents includ^ a vari rce f-cm the above listed Core Requirements. Core Requirement number #5 is activated by special site conditions. Mr. Parsons explained that he worked with Metro consultants, Brown and Caldwell, and Metro staff in preparing the variance technical report and in assuring that the variance request is consistent in striving to meet the spirit of the requirements. The manual was intended to provide flexibility, given the proper technical basis to consider. The Hearing Examiner, notthg that economic hardship generally is not a viable grounds for granting a variance, asked what is the hardship other than the way the applicant designed the plant. Mr. Parsons replied he could show that iu:is an improvement in protection from flooding and storm water quality for the project, and that saving public funds is a benefit. Mr. Parsons continued, noting that pump Metro V-040-91 October 14, 1991 Page 2 systems were specifically not allowed except by variance, but the department is supportive of the pump system proposed as it will help Metro exceed the storm water quality requirements. He also felt that the concerns about pump systems upon which this requirement was based relate to more private systems, lack of attention or maintenance and that the 24-hour maintenance and staffing of Metro's plant erases those kinds of concerns. Core Requirement One, runoff control, related to biofiltration and special water quality controls, need to be varied to allow the interim discharge of storm water and treatment through the treatment plant and discharge to the ETS. Otherwise, Metro's proposal exceeds the performance standards for special requirement number five, thus the variance is only required for interim discharge and treatment through the treatment plant. There is no variance needed at this time to discharge into the two receiving bodies. Parsons recommended that the variances be granted with the one exception that for the discharge at the natural location, Metro be required to fund a more detailed hydrologic/hydraulic study of the impacts of the discharge into P-1 by using the consultants that the City now has developing a detailed watershed plan for the plant. He also recommended that they should be obligated in the future for a covenant to contribute to any future local assessment or improvement district for the Black River basin. The Examiner asked is this analysis after the fact or should this information be available before the variance is granted to allow discharge of water into the P-1 channel. Mr. Parsons replied, it's more that we are asking you to grant the variance prior to knowing the detailed impacts, if any, that they might need to mitigate on site in construction plan development, or in contributing funds toward future expansion of the forebay. Staff does not suspect any problem but feels that it's prudent to have the analysis done. Ms. Gerrie Jackson, Metro 821 Second Avenue, Seattle, 98104, discussed site specific challenges. She said new facilities are being constructed next to old ones, are not separated from existing facilities and in the case of some roadways and parking areas, new will replace old. The treatment plant has an existing storm water system to the Green River outfall, in some places, over 25 feet deep. Much of the property is already being used for sewage treatment or is dedicated to potential future facilities. This plan minimizes cost by using as much of the existing infrastructure as possible. The proposed storm water facilities are not likely to have significant adverse environmental impact. Metro believes you will be able to find that there are special physical circumstances affecting the property which make compliance with the manual unreasonable, i.e. several hundred feet of underground piping, and existing plant facilities which can't be torn down. Jackson explained the variance is necessary to ensure the same rights and privileges as other property in the vicinity, and that granting the variance will not be detrimental to the public or injurious to other property in the vicinity. Metro will implement storm water treatment which is believed to offer equal or better treatment than that described in the manual. Continuing testimony was received from Rick Butler, Brown and Caldwell, 100 W Harrison, Seattle, 98199, who reviewed the site plan showing the plant location; 84.5 acres bounded on the north and east by Oaksdale Avenue and on the west by Monster Road, which currently treats waste water in excess of 72 million gallons per day, utilizing both liquid and solid treatment processes. There are two wetlands on the northern part of the site. The plan will increase the capacity from 72 to 108 million gallons per day (MGD) with a new tank, four new secondary clarifiers and two new dissolved air flotation tanks, plus extensive landscaping and grading including new roads and parking lot construction. Localized bioswales or biofiltration facilities will be located adjacent to the new roadways and parking lot. Construction will cover 3.8 acres, with 1.3 acres for treating the runoff with biofiltration facilities located by Seventh Avenue NE plus three swales near the Administration Building to handle runoff from the eastern portion; one to handle the runoff from the new realignment of the parking lot to the north and a much longer swale to handle the rest of the runoff coming down off the access road as it goes toward the entrance to Monster Road. A biofiltration facility will also be constructed on the south quadrant to treat the runoff and drain into the existing storm water sewer system, which will then flow down through the storm water system to a pump station, needed to lift it out of the underground pipe to surface wetponds. The pump station will be an underground structure, sized for 4 1/2 cubic feet per second, three times the requirement, which will pump through the to-be-abandoned City water main. Flows in excess of that capacity will continue to bypass to the Green River. The wetponds will be over sized to compensate for the runoff from the roadways and parking lots which require biofiltration but because of site constraints cannot be accommodated. A discharge pipe will be constructed to take treated storm water to the P-1 channel which tends to be at a lower flood stage than the Green River, and would allow drainage during storm conditions, thus the request for variance from discharge at natural location, and biofiltration requirement because Metro is not going to be able to supply biofiltration to all the new roads and parking lots. Three times the required volume of water will be sent to the wetponds to give equivalent or better treatment than required to existing water that is not now being treated, plus the new runoff. To be able to gain access to the water main that is going to be abandoned, Metro would like to build the storm water pump station as soon as possible as it will be going in underneath new construction. Since storm water won't be going through any wetpond facilities, Metro is seeking a variance from special requirement number five, water quality. Emergency relief sewers would be built''which would consist of 30 inch lines which would drain by gravity to the P-1 channel to alleviate any potential flooding at the site. These would just allow the storm water system to drain in case of an;extreme flood event. Metro V-040-91 October 14, 1991 Page 3 Louise Kulzer, Metro, 821 Second Avenue, Seattle, 98104, addressed the issues of water quality, stating that her department studies the affects of storm water and its effect on the environment, and she emphasized that Metro supports the need for treatment of storm water both for quality and quantity reasons and the variance that Metro is asking for meets the storm water objectives, but this particular site makes it very difficult to use the exact mode of treatment that is specified by the manual. The proposal provides equivalent water quality treatment. The Examiner asked, if a private applicant requests the same variance, how would Metro react to it under the same circumstances. Ms. Kulzer replied, under the same circumstances, Metro would have no problem, since the water quality objectives are being met. Ms. Kulzer then diagrammed the water quality issues in the proposal, noting that the ponds could be dredged out at a future date. In summary, Rick Butler spoke to the particular variance requirements, noting that Metro met five core requirements and 12 special requirements. Drainage to the P-1 channel is consistent with historical drainage, since before the Metro plant was built there, all that side used to drain to the P-1 channel. Metro feels that discharging to the P-1 channel is not detrimental to the public welfare especially with regards to the emergency relief sewers. Metro also feels that the flows themselves are minimal since, in two year storm events, flows into the P-1 channel are around 600 to 700 cubic feet per second, and the anticipated discharge would be 4 1/2 CFS, which would be about half a percent. Metro would be constructing three wetponds to compensate for those areas that don't get biofiltration, Core Requirement #3. Gerrie Jackson, spoke to the issues, noting that time constraints left the only option to divert through the treatment plant. Typically, storm water is not taken through the treatment plant because it affects capacity. Metro has taken a look at the capacity issues for the short term and feels it has the capacity to handle this amount. Jackson stated, Metro did not look at other options. Metro had the facility available. Concerning emergency flows to the P-1 channel, either the plant could get flooded or the P- 1 channel will accept a certain amount of storm water that is polluted. Elevations of the Green River are such that it really is a critical situation. The P-1 channel is several feet below the Green River during these catastrophic events. Warren Uhte, Brown and Caldwell, 100 W Harrison, Seattle, 98199, spoke to the quality to the P-1 channel, noting in the design that is being proposed, the 4.5 CFS that goes through the wetponds will continue to flow to the P-1 channel even when there is an over flow condition on the rest of the system. He noted the over flow condition is bypassing the wetponds but that always happens under the storm water regulations. Ms. Jackson spoke to the conditions recommended in the letter of September 24, 1991, to the Examiner, from Lynn Guttmann, Public Works Director. Metro proposed changes to the language in condition # 1 and #2, entered as Exhibit # 6. The second proposed condition states that Metro shall participate in a restrictive covenant which would obligate it to participate in future area-wide assessments or LID for improvement and/or maintenance to the P-1 pump plant and channel system, to which Metro has no objection. Metro would participate in an LID, defined on a proportional basis, with some input on proposed improvements. Randall Parsons concurred with Mr. Uhte's statement on water quality, saying Metro does take storm water under special circumstances, or special permit. It was the intention of the people putting forth the manual that the variance process would help foster technical studies for comparison of best management practices. The analysis that Metro did is an example of the kind of technical basis that will be used in updating the manual, which is starting now. If there is a problem in granting the variance now, staff could work with Metro on having the special study done. The Examiner stated that the study should be under the control of the City since the City needs this study. Mr. Parsons spoke to the term, restrictive covenant, and felt that the mechanism could be a letter of agreement acknowledging that they would participate on a proportional basis of any assessments. The Examiner called for further testimony regarding this project. There was no one else wishing to speak, and no further comments from staff. The hearing closed at 10:35 A.M. FINDINGS, CONCLUSIONS & DECISION: Having reviewed the record in this matter, the Examiner now makes and enters the following: FINDINGS: 1. The applicant, the Municipality of Metropolitan Seattle (Metro), filed a request for approval of a series of variances from the requirements of the city's Storm and Surface Water Drainage Ordinance 2. The yellow file containing the staff report, the State Environmental Policy Act (SEPA) documentation and other pertinent materials was entered into the record as Exhibit #1. Metro V-040-91 October 14, 1991 Page 4 3. Metro was the lead agency with respect to the environmental review. An EIS was prepared for the overall treatment plant expansion, although these requests were not specifically reviewed under the EIS. Metro suggested that appropriate SEPA review occurred. 4. The subject proposal was reviewed by all departments with an interest in the matter. 5. The subject site is located at 1200 Monster Road S.W. The subject site is the location of the Renton Metro Wastewater Treatment Plant. 6. The applicant seeks the variances in conjunction with the proposed expansion of the existing plant. The plant expansion was approved under SA-040-91. (See that report for a complete description of the proposed expansion.) 7. The city has adopted the King County Surface Water Design Manual for storm and surface water control provisions. 8. The applicant seeks variances from the following sections of the city code which in part provide: a. Discharge at the Natural Location. The discharge from a proposed project site must occur at the natural location. (Section 1.2(1), King County Surface Water Design Manual) b. Runoff Control. Proposed projects must provide runoff controls to limit the developed conditions peak rates of runoff to the pre-development peak rates for specific design storm events based on the proposed project site existing runoff conditions, and install biofiltration measures. (Section 1.2(3), Ibid.) C. Conveyance System. All conveyance systems for proposed projects must be analyzed, designed and constructed for existing tributary off-site runoff and developed on-site runoff from the proposed project. (Section 1.2(4), Ibid.) d. Special Water Quality Controls. If an area in excess of 1 acre of impervious surface is created which will be used by vehicles or permits the storage of certain chemicals then a wetpond must be employed. (Section 1.3.5, Ibid.) 9. The applicant has proposed a number of methods of treating storm water. While the plant is being expanded and storm water facilities are under construction they proposed that as an interim measure storm water will be collected and mixed with the sanitary sewage, treated in the plant and discharged through the effluent transfer system (a tunnel to Puget Sound) to Puget Sound. Since this discharge would not be at the natural location the applicant has requested a variance. Similarly, most storm water from the site has been released to the Green River since the site was constructed and diked. The applicant proposes restoring the discharge to the P-1 channel which involves a similar variance request. 10. In conjunction with road, parking lot and covered facilities construction the applicant is required to collect and treat storm water in a prescribed manner. This requires appropriately sized and configured detention systems which includes biofiltration. While the applicant will be providing appropriate treatment for approximately one third of the new impervious surfaces, the applicant is constrained by pre-existing construction and road configurations from providing the required treatment adjacent ("local') to some of these new facilities. In place of 'local' treatment the applicant proposes capturing storm water and conveying it through a series of underground pipes to a central location where it will be pumped to new wetponds near the wetlands at the north boundary of the site. 11. The piping system is in place and served the existing plant. Under the then existing regulations storm water was released into the Green River from this system. The applicant now proposes releasing the storm water, except for extraordinary flows, to the P-1 channel to avoid certain requirements and limitations on releasing storm water into the Green River. 12. Instead of using biofiltration swales adjacent to the areas of impervious surfaces they would serve, as indicated above, the applicant would channel storm water to a series of newly constructed wetponds where similar, although not exact, treatment would remove or facilitate the breakdown of contaminants and certain heavy metals. Metro, acting in a dual capacity of applicant and expert, has introduced evidence demonstrating that wetponds can provide treatment equivalent'rto that required by the city requirements. The compatible treatment depends on appropriately sizing the wetponds. Two important factors determining treatment effectiveness are the depth and length of the wetponds. Metro V-040-91 October 14, 1991 Page 5 13. The applicant will pump the accumulated storm water to three linked wetponds where treatment will occur. Water will flow from one pond to the next by gravity flow. After treatment, the storm water would be released to Springbrook Creek. The wetponds have been designed to provide three (3) times the storage required under the code. 14. Storm water in excess of pump capacity will be released to the Green River under an agreement with the flood control agency. There would also be emergency release of untreated or minimally treated storm water to the P-1 channel during some flood periods. Metro maintains that the initial "flush" during severe storm events would receive treatment and only dilute storm water would reach the P-1 channel at these times. The pump, like the wetponds, has been designed to handle three (3) times the storm water otherwise required under city regulations. Since pumps are generally not permitted in the storm drainage system the applicant has sought a variance from the pump language of Section 1.2.4 but further has asked that the requirements for permitting the pump be varied so that the applicant does not have to size the pump storage facility to hold 25 percent of the total volume of runoff for the developed tributary drainage area for the 2-year, 24-hour duration design storm event. 15. Since Metro proposes using an existing system, including a converted water pipe, storm water from existing runoff which is not otherwise required to be treated under these new regulations, will be treated. It would be impossible to distinguish between 'old' or existing storm water and 'new' storm water once it enters the unified underground system. The proposed use of the pipe currently used for water is also one of the reasons for the proposed delay in bringing the system on-line. The water pipe will not be abandoned until other work on the site is complete. In addition, in terms of costs, Metro would prefer avoiding the duplicative expense of installing a new line when the old water line would work just as well. 16, Staff recommended that the following conditions be imposed on the grant of the variance from the Section 1.2(1) (Discharge at the Natural Location). a. Metro shall fund a detailed hydrologic/hydraulic analysis, to be performed by the City's Eastside Green River Watershed Plan consultants using the City's verified continuous simulation hydrologic and hydraulic models, to analyze the impacts (and propose appropriate mitigation) for the proposal to allow discharge of emergency relief flows into the P-1 channel/pumping plant system. Mitigation measures could involve Metro funding the construction of additional forebay/channel storage for the P-1 pumping plant. b. Metro shall endorse a restrictive covenant which will obligate them to participate in any future area wide assessments or local improvement fees for future improvements and/or maintenance to the P-1 pump plant and channel system. 17. Metro proposed alternative language for choosing and retaining a consultant, making costs clearly attributable to Metro's impacts and removed language utilizing the restrictive covenant mechanism for assuring compliance with participation. CONCLUSIONS 1. Variances from the storm water drainage requirements may be granted when the property generally satisfies all the conditions described in Section 4-22-16(A): No variance shall be granted unless the Examiner finds: 1. That there are special physical circumstances or conditions affecting said property such that the strict application of the provisions of this Ordinance would deprive the applicant of the reasonable use or development of his land; 2. That the variance is necessary to insure such property the rights and privileges enjoyed by other properties in the vicinity and under similar circumstances; and 3. That the granting of the variance will not be detrimental to the public welfare or injurious to other property in the vicinity. Further, Section B provides the following mandatory criteria: Criteria: Before the'Examiner grants a variance, he shall make a determination that shall include, but is not limited to, the following criteria: 1. Capacity of'downstream facilities; Metro V-040-91 October 14, 1991 Page 6 2. Acceptability of receiving bodies of water; 3. Possibility of adverse effects of retention; 4. Utility of regional retention facilities; and 5. Capability of maintaining. Finally, Section A also provides: "The Hearing Examiner may prescribe conditions that he deems necessary to be desirable for the public interest." 2. Staff recommended as a condition of variance approval that the applicant provide a detailed analysis of the downstream capacity of the P-1 system which includes the channel, the forebay and the pump station. It seems that this is just the type of information which shall be proved in the first place in order to grant a variance. This office cannot condition the grant of a variance upon the eventual submission of facts which as a matter of course must be demonstrated to justify a variance in the first place. The arrangement and suggestion is contrary to the ordinance's plain language and quite illogical. If the capacity of downstream facilities must be adequate before a variance can be issued, determining that capacity after approval as a condition of variance approval is contrary to law. 3. In addition, the suggestion that further permitting or analysis required by another ordinance such as under the Shoreline Master Program review will act as a catchall is unsatisfactory. The variance criteria clearly states: "Before the Examiner grants a variance, he shall make a determination that shall include, but not be limited to, the following criteria: 1. Capacity of downstream facilities;" It is clear that such a determination of capacity is impossible if the study is done after the variance is granted. 4. Similarly, this office cannot vary the specific criteria necessary to permit a pump system in the storm drainage conveyance system. The request to issue a variance from the specially enumerated requirements for approving a variance from the "pump" criteria is unwarranted. The applicant proposes using dual pumps to move water from the initial detention system to the wetponds. The applicant suggests the dual pumps should adequately replace the storage facility which is required to hold 25% of the runoff. The dual pumps the applicant suggests should take the place of the 25% capacity are already required if a pump is used and so is the 25% capacity. It is not a vice/versa situation. If a pump is used it must be a dual pump and the 25% capacity must be supplied. The applicant is piling variances upon variances leaving little of the code provisions that are not circumvented. 5. The applicant has cited two limitations which they use to justify variance relief. One is the configuration of the existing complex, while the second is the potential expansion which would usurp other currently available land. They have also noted the limitations of some of the current system to justify relief. The fact that the applicant has an existing system does not appear sufficient cause for variance relief. Nor should the limitations of some existing vault/storage capacity of the proposed pumping station provide justification. If existing limitations on an approximately half developed 84 acres can be cited as cause for variance relief than an undue precedent would be created. Such a justification would then be available to most other developers potentially opening the stage for wholesale variances and little compliance with the admittedly stringent, costly and land intensive requirements. 6. Additionally, while the physical location of the existing facilities may possibly be used to justify some variance relief, the future expansion plans cannot be used to justify variance relief. As the applicant indicated, there may well be potential area on the site that could serve some of these intended purposes but that they were not explored given the applicant's current time line. 7. Variance relief is not justified unless there are real physical constraints and not just inconveniences. Variances also are not available to relieve an applicant of self-created hardships, time constraints or most economic hardship. 8. It is unfortunate, but-most of these variances are inextricably linked with one another and separating them out is'difficult, if not impossible. While the Examiner understands Metro's Metro V-040-91 October 14, 1991 Page 7 position, that does not necessarily justify the relief they seek. As the preeminent water quality agency in the area, they need to comply with the requirements that are being imposed upon others unless they can specifically demonstrate undue hardship and deprivation of "reasonable use" of the site. Mere inconvenience, existing but antiquated or limited infrastructure and economics are not justifications. 9. Telling is the 2nd sentence of the 2nd full paragraph on Page 4 of the applicant's September 16, 1991 "Application for variance pursuant to 4.22-16" The applicant states: "To the extent these four requirements reference or incorporate other sections of the KCSWDM, Metro requests a variance from those sections as well." It is not possible to grant variances in such summary fashion. Vague requests for variances that have not been identified also cannot be granted. Each one must be identified and each must be justified. It is incumbent on the applicant to identify each section of the code that requires a variance. 10. With the above discussion out of the way, it appears that this office can distinguish two of the variances although without the additional relief the applicant has unsuccessfully sought, these two may not be of much consequence. The variance to permit interim discharge to the treatment plant's sanitary sewerage stream is appropriate since an alternative storm water disposal system will be necessary until a more permanent system is constructed. The release of storm water to the treatment plant instead of their natural outlets will probably have some impacts but they should be minimal. In addition, disturbance of the storm water's natural flow is not unusual during construction phases of a project. It would be physically impossible to provide the normal code requirements for managing storm water at a site with this much construction activity while constructing the final facilities that will eventually manage it. Therefore, the variance to release storm water to other than the natural location is approved. 11. The other variance that appears reasonable given the need for perimeter roads and existing and proposed parking areas is the use of three linked wetponds instead of biofiltration swales to serve impervious surfaces. The topography of the site, the location of the existing wetland and the nature of the complex's facilities justify the substitution of wetponds for the mandated treatment. The applicant has demonstrated that the proposed wetponds in this instance provide similar, although, not equivalent treatment. In some instances more or equal amounts of one type of contaminant would be removed (lead, phosphorus, total dissolved solids), while in what appears to be one instance less of another would be removed (zinc). In the latter case, zinc has not been determined to be a problem in the potential receiving waters. Under the circumstances approval of the wetponds alternative would not result in injury or harm to either the public or other property in the vicinity. 12. Unfortunately, at this time, a companion variance to approve release of wetpond treated storm water to the P-1 channel cannot be approved. The absence of information on the downstream capacity of the P-1 system rules that out. 13. In summary, the applicant has not demonstrated the proof necessary to approve some of the variance requests, in some cases has not clearly identified what variances have been requested, and finally, in some cases has not demonstrated the necessary unique hardship, as opposed to mere provisional constraints, necessary to justify a variance. These variances, those specifically identified and those supposedly incorporated into the application are denied. The applicant has demonstrated, as indicated above, that two variances are justified and they are hereby approved. DECISION 1. The variance to release storm water to the treatment plant and discharge it to the Effluent Transfer System is approved for an interim until permanent facilities are constructed, but in no event shall this variance exceed four (4) years. Any extension of the time period shall be subject to a new application for variance relief. 2. The variance to permit the use of three linked wetponds instead of biofiltration swales is approved. 3. Any other variance whether identified or implicit in the application is denied. ORDERED THIS 14th day of October, 1991. FRED 1. KAQ4FMAN HEARING EXAMINER Metro V-040-91 October 14, 1991 Page 8 TRANSMITTED THIS 14th day of October, 1991 to the parties of record: Gerrie Jackson Metro 821 Second Avenue Seattle, WA 98104 Rick Butler Brown & Caldwell 100 W Harrison Seattle, WA 98199 Louise Kulzer Metro 821 Second Avenue Seattle, WA 98104 Warren Uhte Brown & Caldwell 100 W Harrison Seattle, WA 98199 Randall Parsons Storm Water/Waste Water City of Renton TRANSMITTED THIS 14th day of October, 1991 to the following: Mayor Earl Clymer Councilman Richard M. Stredicke Don Erickson, Zoning Administrator Lynn A. Guttmann, Administrator Members, Renton Planning Commission Jim Hanson, Development Services Manager Gary Gotti, Fire Marshal Ronald Nelson, Building Director Lawrence J. Warren, City Attorney Jay Covington, Mayor's Executive Assistant Transportation Systems Division Valley Daily News Utilities System Division Pursuant to Title IV, Chapter 8, Section 15 of the City's Code, request for reconsideration must be filed in writing on or before 5:00 P.M. October 28, 1991. Any aggrieved person feeling that the decision of the Examiner is ambiguous or based on erroneous procedure, errors of law or fact, error in judgment, or the discovery of new evidence which could not be reasonably available at the prior hearing may make a written request for a review by the Examiner within fourteen (14) days from the date of the Examiner's decision. This request shall set forth the specific ambiguities or errors discovered by such appellant, and the Examiner may, after review of the record, take further action as he deems proper. Any appeal is governed by Title IV, Chapter 8, Section 11, which requires that such appeal be filed with the Superior Court of Washington for King County within twenty (20) days from the date of the Examiner's decision. The Appearance of Fairness Doctrine provides that no ex parte (private one-on-one) communications may occur concerning pending land use decisions. This means that parties to a land use decision may not communicate in private with any decision-maker concerning the proposal. Decision-makers in the land use process include both the Hearing Examiner and members of the City Council. All communications concerning the proposal must be made in public. This public communication permits all interested parties to know the contents of the communication and would allow them to openly rebut the evidence. Any violation of this doctrine would result in the invalidation of the request by the Court. The Doctrine applies not only to the initial public hearing but to all Requests for Reconsideration as well as Appeals to the City Council. Proposed Revisions to Recommended Conditions Metro shall fund a detailed hydrologic/hydraulic analysis, River Watershed Plan consuitants using the City' s verified continuous simulation hydrologic and hydraulic models, to analyze the impacts (and propose appropriate mitigation) for the proposal to allow discharge of emergency relief flows into the P-1 channel/pumping system. The study shall be performed by a consultant mutually agreed upon by Metro and the City and hired by Metro. Metro shall have the opportunity to comment upon the scope and on all drafts of the study. Mitigation measures could involve Metro funding the construction of additional forebay/channel storage for the P-1 pumping plant, provided such measures are reasonable and limited to impacts attributable to Metro ' s discharge. Metro shall enderse a restrietive eevenant wh eh ..: l participate on a proportional basis in any reasonable future area wide assessments or local improvement fees for future improvements and/or maintenance to the P-1 pump plant and channel system. :1:R1ETRO „ Municipality of Metropolitan Seattle Exchange Building • 821 Second Ave. • Seattle,WA 98104-1598 October 5, 1991 n �-J Mr. Fred Kaufman, Hearing Examiner I°J1 City of Renton 200 Mill Avenue South T_ Ci'il Renton, Washington 98055 Treatment Plant Expansion III/Storm Water Variance Dear Mr. Kaufman: We are offering by the enclosed letter some information for your consideration regarding Metro's storm water variance application. The information clarifies and corrects Metro's response to a question raised at the hearing. Specifically, the letter addresses: Metro's policy for allowing storm water to be run through the treatment plant. We realize that the public hearing for this variance application has concluded. However, since this information was learned after the hearing through discussions with various Metro personnel and since it is offered by way of clarification, we wonder if you could reopen the record for the limited purpose of accepting this letter or otherwise take notice of the letter. A copy of this letter has been sent to the other attendees at the hearing, Mr. Randall Parsons and Mr. Paul Forsander. Thank you for your consideration. Sincerely, GI! a Jackson, SR/WA Permit Coordinator GJ:ce enclosure cc: Mr. Randall Parsons Mr. Paul Forsander Ms. Laurie Endlich Ms. Vicki Renier Mr. Joe Fernandes Mr. Rick Butler Mr. Warren Uhte G:GJR3L2 r ::R1ETRO /► Municipality of Metropolitan Seattle Exchange Building • 821 Second Ave. • Seattle, WA 98104-1598 October 5 , 1991 Mr. Fred Kaufman, Hearing Examiner City of Renton 200 Mill Avenue South Renton, Washington 98055 Treatment Plant Expansion III/Storm Water Variance Dear Mr. Kaufman: We would like to offer the following as clarification of cur response to the following question: Would we allow other property owners to put storm water through the treatment plant such as we are proposing to do? In checking with the Water Pollution Control Division of Metro, it appears that there is significant precedent for allowing stormwater discharge through the treatment plant. Several industrial property owners have been allowed to discharge storm water through the treatment plant. Who is allowed to do so is determined on a case by case basis as determined by the Industrial Waste Division. Cases such as the Metro interim discharge have been evaluated and allowed in the past. We hope that this clarification will assist you in your decision making process. Sinc rely, G rie Jackson, SR/WA Permit Coordinator GJ:ce G:GJR3L1 CITY OF RENTON HEARING EXAMINER PUBLIC HEARING AGENDA CI OMMENCING AT 9:00 AM, OCTOBER 1, 1991 COUNCIL CHAMBERS, SECOND FLOOR, RENTON MUNICIPAL BUILDING The application(s) listed are in order of application number only and not necessarily the order in which i they will be heard. Items will be called for hearing at the discretion of the Hearing Examiner. PROJECT NAME: Variance From Chapter 22 Storm And Surface Water Drainage For Metro Plant Expansion, Phase III PROJECT NUMBERS: SA;SM;SP-040-91 PROJECT DESCRIPTION: The applicant has requested a variance from requirements contained in Section 4-22-8 of the City Code: Drainage Plan Requirements and Methods of Analysis to allow expansion of the existing Metro Treatment Plant at Renton. The applicant has requested a variance from the following: Core Requirement #1: Discharge at natural location; Core Requirement #3: Runoff Control; Core Requirement #4: Conveyance System; and Core Requirement #5: Special Water Quality Controls. The project is located at 1200 Monster Rd SW. I DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS PRELIMINARY REPORT TO THE HEARING EXAMINER PUBLIC HEARING APPLICANT: Municipality of Metropolitan Seattle (Metro) PROJECT NAME: STORM WATER VARIANCE FOR: Metro Wastewater Treatment Plant, Expansion III FILE NUMBER: SA;SM;SP-040-91 LOCATION: SEC: 24; TWMSHP: 23N; PING: 4E 1200 Monster Rd SW, Renton A. SUMMARY AND PURPOSE OF REQUEST: The applicant has requested a variance from requirements contained in Section 4-22-8 of the City Code: Drainage Plan Requirements and Methods of Analysis to allow expansion of the existing Metro Treatment Plant at Renton. The applicant has requested a variance from the following: Core Requirement #1: Discharge at natural location; Core Requirement #3: Runoff Control; Core Requirement #4: Conveyance System; and Core Requirement #5: Special Water Quality Controls. The project is located at 1200 Monster Rd SW. On July 2, 1991, the Hearing Examiner approved the site plan for the proposed waste water treatment plant expansion. The expansion was approved for three development phases: Phase A (1991-1993): Site Preparation (vegetation clearing, excavation, fill, grading and site dewatering) and Perimeter Landscaping; Phase B (1993-1996): Facility Construction; and Phase C (1996): Interior Landscaping and Site Clean-Up. B. GENERAL INFORMATION: 1. Owner of Record: Municipality of Metropolitan Seattle (Metro) 2. Applicant: Municipality of Metropolitan Seattle (Metro)/Gerrie Jackson 3. Existing Zoning: P-1, Public Use 4. Existing Zoning In the Area: City of Renton Zoning: B-1, Business Use; M-P, Manufacturing Park; L-1, Light Industry; O-P, Office Park; P-1, Public Use; City of Tukwila Zoning: RA, Agricultural; C-2, Regional Retail; M-1, Light Industry. 5. Comprehensive Land Use Plan: Public/Quasi-Public 6. Size of Property: 84.5 Acres 7. Access: SW Grady Way Via Monster Road SW or Oaksdale Ave SW Via SW 7th St Bridge over Springbrook Creek. 8. Land Use: Metro Wastewater Treatment Plant 9. Neighborhood Characteristics: North: Undeveloped (Proposed Office Park) East: Office Park and Springbrook Creek South: Industrial and 1-405 West: Industrial and Black River Channel PRELRPT2 r . PRELIMINARY REPORT TO THE HEARING EXAMINER STORM WATER VARIANCE FOR METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING October 1, 1991 Page 2 C. HISTORICAL/BACKGROUND: Action File Ordinance Date Annexation 1745 4-14-59 Amend. Ord. 1764 5-27-59 Amend. Ord. 1928 12-22-61 Special Permit SP-065-81 Special Permit SP-006-83 Conditional Use CU-007-83 Substantial Shoreline SM-107-83 Variance V-045-84 Conditional Use CU-087-84 Variance V-088-84 Substantial Shoreline SM-118-84 Rezone R-046-85 3961 12-13-86 Shoreline Exemption SME-003-85 Site Plan Approval SA-061-87 Special Permit SP-062-87 Site Plan Approval SA;SM;SP-040-91 7-02-91 D. PUBLIC SERVICES: 1. Utilities a. Water: A number of private (Metro) 12-Inch water lines serve the site. These mains Interconnect with the City of Renton Water System. b. Sewer: A 12-Inch sanitary sewer serves the site perimeter (see attached map). There are a number of Metro-owned sewers on-site. C. Storm Water Dralnaoe: RANDALL TO UPDATE Existing storm water runoff from impervious surfaces Is collected and discharged to the Green River. Future runoff from the proposed expansion will also be collected, treated on-site and discharged consistent with National Pollutant Discharge Elimination System (NPDES) permit requirements and other applicable regulations, such as the City of Renton's adoption of the King County Surface Water Design Manual. E. APPLICABLE SECTIONS OF THE ZONING CODE: 1. Section 4-22, Storm and Surface Water Drainage. F. APPLICABLE SECTIONS OF THE COMPREHENSIVE PLAN OR OTHER OFFICIAL CITY DOCUMENT: 1. Policies Element, VIII -Utilities Goal, D. Sanitary Sewers Objective, City of Renton Comprehensive Plan Compendium, 1986, pp 22-23. 2. King County Surface Water Design Manual, 19_ 4. Shoreline Master Program, City of Renton, Adopted by Ordinance No. 3758. PREL "2 PRELIMINARY REPORT TO THE HEARING EXAMINER STORM WATER VARIANCE FOR METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING October 1, 1991 Page 3 G. DEPARTMENT ANALYSIS: 1. BACKGROUND The applicant has requested a variance from requirements contained in Section 4-22-8 of the City Code: Drainage Plan Requirements and Methods of Analysis to allow expansion of the existing Metro Treatment Plant at Renton. The applicant has requested a variance from the following: Core Requirement #1: Discharge at natural location; Core Requirement #3: Runoff Control; Core Requirement#4: Conveyance System; and Core Requirement #5: Special Water Quality Controls. The project is located at 1200 Monster Rd SW. On July 2, 1991, the Hearing Examiner approved the site plan for the proposed waste water treatment plant expansion. The expansion was approved for three development phases: Phase A (1991-1993): Site Preparation (vegetation clearing, excavation, fill, grading and site dewatering) and Perimeter Landscaping; Phase B (1993-1996): Facility Construction; and Phase C (1996): Interior Landscaping and Site Clean-Up. 2. ENVIRONMENTAL ANALYSIS Metro, as lead agency for the proposed action, prepared an EIS for the project. The EIS was a Supplemental EIS which supplements the environmental reviews for wastewater treatment plant expansion which were completed in 1981 and 1986 by Metro. The Supplemental EIS is a project- level EIS for expanding Metro's facilities at Renton to treat up to 108 mgd. According to Metro, the EIS was used to select a final layout for implementing the expansion of the wastewater treatment plant, and to support application for project permits. The Final Supplemental EIS was issued on May 24, 1991. The Final EIS was revised in response to written comments received during the public comment period. Supplemental Environmental Analysis For the Proposed Storm Water Design and Variance Request METRO TO PROVIDE TEXT TO PAUL FORSANDER BY SEPT. 23 NOON 3. PROPOSED STORMWATER DESIGN RANDALL INSERT TEXT 4. COMPLIANCE WITH STORM WATER CODE (CHAPTER 22) VARIANCE CRITERIA a) That there are special physical circumstances or conditions affecting said property such that the strict application of the provisions of this Ordinance would deprive the applicant of the reasonable use or development of his land. RANDALL b) That the variance is necessary to insure that such property the rights and privileges enjoyed by other properties in the vicinity and under similar circumstances. RANDALL c) that the granting of the variance will not be detrimental to the public welfare or injurious to other property in the vicinity. RANDALL d) Compliance with technical criteria: 1) Capacity of downstream facilities. RANDALL 2) Acceptability of receiving bodies of water. RANDALL 3) Possibility of adverse effects of retention. RANDALL PRELRPT2 PRELIMINARY REPORT TO THE HEARING EXAMINER STORM WATER VARIANCE FOR METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING October 1, 1991 Page 4 4) Utility of regional retention facilities. RANDALL 5. Capability of maintaining. RANDALL H. DEPARTMENTAL RECOMMENDATION: Staff recommend that the Hearing Examiner determine In favor of the requested variance from the following requirements contained in Section 4-22-8 Drainage Plan Requirements and Methods of Analysis of the City Code: Core Requirement #1: Discharge at natural location; Core Requirement #3: Runoff Control; Core Requirement #4: Conveyance System; and Core Requirement #5: Special Water Quality Controls, for Metro's Wastewater Treatment Plant, Expansion III (File No. SA;SM;SP-040-91), subject to the following conditions: 1. RANDALL 2. 3.. 4. PRELRPT2 cti T CITY OF RENTON 9 Planning/Building/Public Works Department Earl Clymer, Mayor Lynn Guttmann,Administrator September 24, 1991 Greg Bush, Manager Environmental Compliance METRO Exchange Building 821 2nd Ave. Seattle, WA. 98104 SUBJECT: APPLICATION FOR VARIANCE TO STORMWATER DRAINAGE CODE FOR METRO RENTON TREATMENT PLANT ENLARGEMENT III Dear Mr. Bush, We have reviewedour variance application request for a variance from several of the requirements contained in Section 4-22-8 of the City Storm and Surface Water Drainage Code: Drainage Plan Requirements and Methods of Analysis,for the interim and permanent storm drainage facilities needed for the expansion of the Metro Treatment Plant at Renton. These requirements include a variance from the following: Core Requirement#1: Discharge at Natural Location; Core Requirement#3: Runoff Control; Core Requirement#4: Conveyance System; and Core Requirement#5: Special Water Quality Controls. Randall Parsons, the City's Stormwater and Wastewater Utility Engineering Supervisor, has worked closely with METRO's staff and your consulting firm to prepare the variance request application and accompanying technical report. He has reviewed and supports the justification and conclusions provided in the application with the exception of the need for further detailed analysis related to the potential impacts to the P-1 channel/pumping plant system as noted below. We have therefore recommended that the City's Hearing Examiner grant the variance request, with the following conditions added with regards to the proposed variance to Core Requirement #1: Discharge at the Natural Location: (1) METRO shall fund a detailed hydrologic/hydraulic analysis,to be performed by the City's Eastside Green River Watershed Plan consultants using the City's verified continuous simulation hydrologic and hydraulic models,to analyze the impacts (and propose appropriate mitigation) for the proposal to allow discharge of emergency relief flows into the P-1 channel/pumping plant system. Mitigation measures could involve METRO funding the construction of additional forebay/channel storage for the P-1 pumping plant. (2) METRO shall endorse a restrictive covenant which will obligate them to participate in any future area wide assessments or local improvement fees for future improvements and/or maintenance to the P-1 pump plant and channel system. We should note that our recommendation for approval of this variance request does not constitute approval of the construction permits and related engineering analyses for the drainage facilities conceptually proposed in the variance request application and accompanying technical report. For example,the proposed emergency relief storm sewer connections or work in the P-1 channel system would require a Shorelines permitting process. 200 Mill Avenue South - Renton, Washington 98055 September 24, 1991 Page 2 of 2: Greg Bush METRO Stormwater Variance Application Randall will be attending the hearing scheduled for Tuesday, October 1, 1991 at 9:00 a.m.. If you or your staff have any additional questions prior to this date, please call him at 277-5548. Very truly yours, Lyn�Guff ann, Administrator Dep'artme of Planning/Building/Public Works LG:RP:rrpp cc- Gerrie Jackson, Permit Coordinator,METRO,Right-of-Way/Property Department Richard Anderson,Utility Systems Division Manager Randall Parsons,Utility Engineering Supervisor,Stormwater and Wastewater Utility Section Jim Hanson,Development Services Division Manager Don Erickson,Zoning Administrator,Development and Planning Section Paul Forsander,Senior Planner, Development and Planning Section Fall ' alp Q Deli CONCURRENCE DATE L-2y I21 September 24, 1991 NAME INITIAL/DATE Greg Bush, Manager Environmental Compliance METRO Exchange Building 821 2nd Ave. Seattle, WA. 98104 SUBJECT: APPLICATION FOR VARIANCE TO STORMWATER DRAINAGE CODE FOR METRO RENTON TREATMENT PLANT ENLARGEMENT III Dear Mr. Bush, jb�rt- We have review application uqueGFfor avariance from several of the requirements contained in Section 4-22-8 of the City Storm and Surface Water Drainage Code: Drainage Plan Requirements and Methods of Analysis, for the interim and permanent storm drainage facilities needed for the expansion of the Metro Treatment Plant at Renton. These requirements include a variance from the following: Core Requirement #1: Discharge at Natural Location; Core Requirement#3: Runoff Control; Core Requirement #4: Conveyance System; and Core Requirement#5: Special Water Quality Controls. Randall Parsons, the City's Stormwater and Wastewater Utility Engineering Supervisor, has worked closely with METRO's staff and your consulting firm to prepare the variance request application and accompanying technical report. He has reviewed and supports the justification and conclusions provided in the application with the exception of the need for further detailed analysis related to the potential impacts to the P-1 channel/pumping plant system as noted below. We have therefore recommended that the City's Hearing Examiner grant the variance request, with the following conditions added with regards to the proposed variance to Core Requirement#1: Discharge at the Natural Location: (1) METRO shall fund a detailed hydrologic/hydraulic analysis, to be performed by the City's Eastside Green River Watershed Plan consultants using the City's verified continuous simulation hydrologic and hydraulic models, to analyze the impacts (and propose appropriate mitigation)for the proposal to allow discharge of emergency relief flows into the P-1 channel/pumping plant system. Mitigation measures could involve METRO funding the construction of additional forebay/channel storage for the P-1 pumping plant. (2) METRO shall endorse a restrictive covenant which will obligate them to participate in any future area wide assessments or local improvement fees for future improvements and/or maintenance to the P-1 pump plant and channel system. We should note that our recommendation for approval of this variance request does not constitute approval of the construction permits and related engineering analyses for the drainage facilities conceptually proposed in the variance request application and accompanying technical report. For example, the proposed emergency relief storm sewer connections or work in the P-1 channel system would require a Shorelines permitting process. September 24, 1991 Page 2 of 2: Greg Bush METRO Stormwater Variance Application Randall will be attending the hearing scheduled for Tuesday, October 1, 1991 at 9:00 a.m.. If you or your staff have any additional questions prior to this date, please call him at 277-5548. Very truly yours, Lynn Guttmann, Administrator Department of Planning/Building/Public Works LG:RP:rp cc. Gerrie Jackson,Permit Coordinator,METRO,Pightof-Way/Property Department Richard Anderson, Utility Systems Division Manager Randall Parsons, Utility Engineering Supervisor,Stormwater and Wastewater Utility Section Jim Hanson, Development Services Division Manager Don Erickson,Zoning Administrator, Development and Planning Section Paul Forsander,Senior Planner, Development and Planning Section r CITY OF RENTON MEMORANDUM DATE: September 24, 1991 TO: Fred Kaufman, Hearing Examiner FROM: Ly ann, Administrator PI nning B ilding/Public Works STAFF CONTACT: Randall Parsons, Utility Engineering Supervisor Stormwater and Wastewater Utility Section SUBJECT: APPLICATION FOR VARIANCE TO STORMWATER DRAINAGE CODE FOR METRO RENTON TREATMENT PLANT ENLARGEMENT III METRO has requested a variance from several of the requirements contained in Section 4-22-8 of the City Storm and Surface Water Drainage Code: Drainage Plan Requirements and Methods of Analysis,for the interim and permanent storm drainage facilities needed for the expansion of the Metro Treatment Plant at Renton. These requirements include a variance from the following: Core Requirement#1: Discharge at Natural Location; Core Requirement#3: Runoff Control; Core Requirement#4: Conveyance System; and Core Requirement#5: Special Water Quality Controls. Randall has worked closely with METRO staff and their consulting firm to prepare the enclosed variance request application and accompanying technical report (enclosed). Prior to coming to the City Randall was the project manager and one of the principal authors of the King County Surface Water Design Manual (KCSWDM) which contains the aforementioned requirements. He had noted that most of the water quality requirements and facility design criteria in the KCSWDM were based on research papers prepared under the direction of METRO's Water Quality Planning Section in the Water Pollution Control Department. He therefore requested and received the enclosed letter from that Departmer t to provide further technical support to the adequacy of the proposed stormwater quality measures METRO has proposed in lieu of strictly conforming to the standard KCSWDM requirements. Randall would also like to note that a substantial portion of the stormwater runoff from the"existing" METRO Treatment Plant's impervious surfaces, which are not required to be retrofitted under current City Codes for the proposed Plant improvements, will in fact be treated under METRO's proposed stormwater management plan. He has reviewed and supports the justification and conclusions provided in the application with the exception of the need for further detailed analysis related to the potential impacts to the P-1 channel/pumping plant system as noted below. We are therefore recommending that you grant the variance request,with the following conditions added with regards to the proposed variance to Core Requirement#1: Discharge at the Natural Location : (1) METRO shall fund a detailed hydrologic/hydraulic analysis, to be performed by the City's Eastside Green River Watershed Plan consultants using the City's verified continuous simulation hydrologic and hydraulic models, to analyze the impacts (and propose appropriate mitigation) for the proposal to allow discharge of emergency relief flows into the P-1 channel/pumping plant system. Mitigation measures could involve METRO funding the construction of additional forebay/channel storage for the P-1 pumping plant. METRO Treatment Plant Expansion Storm Drainage Code Variance Request September 24, 1991 Page 2 of 2 (2) METRO shall endorse a restrictive covenant which will obligate them to participate in any future area wide assessments or local improvement fees for future improvements and/or maintenance to the P-1 pump plant and channel system. Randall will be attending the hearing scheduled for Tuesday, October 1, 1991 at 9:00 a.m.. If you have any questions during your review of the enclosed materials prior to this date, please call him at X-5548. oc Dick Anderson,Utility Systems Division Manager Don Erickson,Zoning Administrator,Development and Planning Section Paul Forsander,Senior Planner,Development and Planning Section enclosures ;CINCURRENCE ^ATE �4ZOZ- ND/UE INITIALED —� CITY OF RENTON Gy_ MEMORANDUM DATE: September 24, 1991 TO: Fred Kaufman, Hearing Examiner FROM: Lynn Guttmann, Administrator Planning/Building/Public Works STAFF CONTACT: Randall Parsons, Utility Engineering Supervisor Stormwater and Wastewater Utility Section SUBJECT: APPLICATION FOR VARIANCE TO STORMWATER DRAINAGE CODE FOR METRO RENTON TREATMENT PLANT ENLARGEMENT III METRO has requested a variance from several of the requirements contained in Section 4-22-8 of the City Storm and Surface Water Drainage Code: Drainage Plan Requirements and Methods of Analysis,for the interim and permanent storm drainage facilities needed for the expansion of the Metro Treatment Plant at Renton. These requirements include a variance from the following: Core Requirement#1: Discharge at Natural Location; Core Requirement#3: Runoff Control; Core Requirement#4: Conveyance System; and Core Requirement#5: Special Water Quality Controls. Randall has worked closely with METRO staff and their consulting firm to prepare the enclosed variance request application and accompanying technical report (enclosed). Prior to coming to the City Randall was the project manager and one of the principal authors of the King County Surface Water Design Manual (KCSWDM) which contains the aforementioned requirements. He had noted that most of the water quality requirements and facility design criteria in the KCSWDM were based on research papers prepared under the direction of METRO's Water Quality Planning Section in the Water Pollution Control Department. He therefore requested and received the enclosed letter from that Department to provide further technical support to the adequacy of the proposed stormwater quality measures METRO has proposed in lieu of strictly conforming to the standard KCSWDM requirements. Randall would also like to note that a substantial portion of the stormwater runoff from the "existing" METRO Treatment Plant's impervious surfaces, which are not required to be retrofitted under current City Codes for the proposed Plant improvements, will in fact be treated under METRO's proposed stormwater management plan. He has reviewed and supports the justification and conclusions provided in the application with the exception of the need for further detailed analysis related to the potential impacts to the P-1 channel/pumping plant system as noted below. We are therefore recommending that you grant the variance request, with the following conditions added with regards to the proposed variance to Core Requirement#1: Discharge at the Natural Location (1) METRO shall fund a detailed hydrologic/hydraulic analysis, to be performed by the City's Eastside Green River Watershed Plan consultants using the City's verified continuous simulation hydrologic and hydraulic models, to analyze the impacts (and propose appropriate mitigation) for the proposal to allow discharge of emergency relief flows into the P-1 channel/pumping plant system. Mitigation r I involve METRO funding the construction of additional foreba /channel storage for the measures could g Y 9 P-1 pumping plant. METRO Treatment Plant Expansion Storm Drainage Code Variance Request September 24, 1991 Page 2 of 2 (2) METRO shall endorse a restrictive covenant which will obligate them to participate in any future area wide assessments or local improvement fees for future improvements and/or maintenance to the P-1 pump plant and channel system. Randall will be attending the hearing scheduled for Tuesday, October 1, 1991 at 9:00 a.m.. If you have any questions during your review of the enclosed materials prior to this date, please call him at X-55Q. cc Dick Anderson,utility Systems Division Manager Don Erickson,Zoning Administrator, Development and Planning Section Paul Forsander,Senior Planner,Development and Planning Section enclosures I i str-21_"J1 IUt ley=bS lll'ML(C - 121H FLP. 1EL NU' (.Jt bJ LUI-191JU nu4o P02 NAMETRO Municipality of Metrnrolitan Seattle Exchange Building - 821 Second Avc. Scuttle,WA 98104-1598 (206)684-2100 September 19, 1991 Ms. Lynn Guttmann Renton Public Works Department Municipal Building 200 Mill Avenue South Renton, WA 98055 Dear Ms, Guttmann: 'Phis letter is to provide technical back up for Metro's letter of September 16, 1991, requesting a variance to some of the specific requirements of the King County Surface Water Design Manual (KCSWDM) which has been adopted by Renton for stormwater management. Metro's proposed stormwater management system for the Renton Treatment Plant site was developed to meet the water quality objectives of the KCSWDM, and provide water quality performanace equivalent to that expected from the core requirements. Metro's proposed design involves less reliance on grassy swales than specified by the core requirements, but compcnoatc* by ovcrzizing the on-site detention wet pond. As explained in our application, this flexibility is sought because Metro is providing treatment for existinq runoff as well as for the propoeed expansion. The exiting site drainage pipes are placed very deep, which will necessitate pumping the water to the surface for treatment. Because of site constraints and the opportunity to use an existing line for stormwater conveyance, hiofiltratinn vnnld he very costly to implement over the entire site. In brief, the system we are proposing involves providing biofiltration fur exterior roadways and some parking areas, a constructed wetland for an icolated parking area, and treatment of the remaining stormwater in an oversized wet detention pond. About 2/3 of the new impel•vious area, as well as drainage from the existing site, would be treated via the detention pond. Metro believes an oversized wet pond designed to treat the full 2 year-24 hour storm flow will perform significantly better than one sized for 1/3 that flow, as the KCSWDM currently requires. Data to support thin argument are taken from the NationwiQe urbari Runoff Program (NURP) , which studied the performance of wet detention ponds throughout the country (USEPA, 1983) . Walker later analyzed the NURP data, relating water quality performance to engineering design criteria (Walker, 1926) . Four specific design predictors were used in the EPA and Walker reports. They arc an follows: bbY-d'I- ' 1 iuJ 0' :n3 IU:MEL - 1LIfi FLF. 1pL NU: LIDO) bU'I-i'JU'U' IIJ'Il r'UJ f Ms_ T,ynn Guttman September 19, 1991 Pago 2 1) The ratio of pond surface area to the surface area of the drainage, SA/SD; i 2) The ratio of pond volume to the mean storm runoff volume, VB/VR; 3) The surface overflow rate during the mean storm; and 4) Mean hydrualic residence time. In addition, pond configuration and the prevention of short circuiting are important considerations, although no quantitative indices have been developed. Each of these areas will be addressed in turn. Attachments provide numerical backup for the stated removal rates of the proposed pond. Aati_o of pond sur ace area to Surface area of the drainage. in general, the pond surface area should be about 1t of the contributing drainage area to achieve good pollutant removal etriciency. Modeling done for Metro in support of the Lake Sammamish Management Plan suggests that with a pond depth of about 1 motor, almost 90$ removal of total suspended solids (TSS) could be expected. NURP data shows that detention ponds with surface areas greater than it of the watershed area achieved TSS removals of from 60t to 90t. Removal of heavy metals was also superior to that seen in smaller ponds. The proposed detention pond at the Renton site has a surface area of 1. it of the .site drainage area_ Ratio of pond volume to mean storm runoff volume. Ponds having the ratio of pond volume to mean storm runoff volume greater or equal to 1 show better removal efficiencies than ponds in which the ratio is less than one. Metro's proposed pond has a ratio of 2. 3, which corresponds to TSS removals of 60% to 90t in the NURP data. Surface overflow rate. This design predictor is the ratio of the mean storm runoff rate to the pond surface area. in the NURP study, ponds with overflow ratec loco than about 0.1 ft/hr performed best in terms of TSS and metal removals. Metro's proposed pond has an overflow rate of 0.07 ft/hr. Ms. Lynn Guttman September 19, 1991 Page 3 Hydraulic residence time. The longer storm flows are detained, the greater treatment provided, both for T88 as well as for the nutrients nitrogan and phosphorus. In part., nutrient removal in wet ponds is due to biological activity in the water column, a process which is time dependent. Walker estimates that for phosphorus removal of up to 80%, a detention time in excess of 14 days is required. For about 50% phosphorus removal, detention timc2 of 7 - 14 days would be required. TSS removals of 60% to 80% have been seen with detention times of between 6 and 7 days, according to data from NURP and Martin fi Smoot (1986) . As -currently designed, with an active pool volume of about 1 meter, the proposed pond has a detention time of 7 days. Since the receiving watcra (P-1 channel and Green River) are not particularly phosphorus sensitive in the reaches duwnt;Lream of the Treatment Plant, detention times of greater s than 7 days would not seem neoceoary. However, if determined otherwise, it would be pnssihla to arhi.nve a 15 day detention Lime by increasing the pond depth to 2 meters. Pond configuration. A laboratory scale model studied by Horner and Kortenhof (1987) , found that long, narrow pond configurations with two cells achieved longer residence times than single cell configurations. The proposed detention pond design provides Lliree cells, as per the KCSWDM, and a very elongate configuration. Use of three cells and the long, narrow configuration serves to maximize the travel path of storm water i introduced into the pond, and inurease Lhe residence time over that projected on the basis of engineering parameters alone. The attached Table indicates d range of expected annual pollutant removal effectiveness for Metrola proposed enlarged pond size, and the smaller pond size rp.qui.re.d in the Manual. The Table also gives preliminary data about the removal efficiencies of biofiltration cwales. (Biofiltration data was collected this summer as part of an inter-agency project to monitor the pollutant removal effectiveness of grassy swales, and is as yet unpublished. ) The expected pollutant removal performance is given as a range to indicate the variability seen in different parts of the country with allierent pond treatment systems. in general, a much higher annual average level of pollutant removal is expected from large ponds with design characteristics as described previously. Ms. Lynn Cuttman Septambar 19, 1991 Page 4 These data indicate that with an enlarged detention pond sized as proposed; water quality performance equal to or better than that expected from a smaller pond plus biofiltration can be achieved. Metro appreciates your willingness to consider our request for flexibility in the manner the requirements and water quality objectives of the RC WDM can be met. If you have questions about the data presented, please contact me at 684-1551 or Louise Kulzer, at 684-2063 . Additional background information can be found in Metro's publication "Considerations for the Use of Wet Ponds for Water Quality Enhancement. " References cited in this letter are appended. very truly ours, ohn F. Spencer Director Water Pollution Control Department JFS:lkk Enclosures I emu( Pollutant Removal Performance of Large and Small Detention Ponds and Grassy Swales -Pollutant Percent Removal Observed Large ponds Smaller ponds Grassy swalee (average of 4 storms) Total dissolved 60 - 90t neg. - 30k 80% solids (TGS) Total phosphorus 3 - 801 neg. - 30$ y$ Total Kjeldhhl d nitrogen ncg - 60* neg. - 20% neg. Total lead 80 - 90% 10 - 601 70% Total zinc neg. - 70% 0 - 10% 60% Notes: Detention pond data is from NURP, UGEPA, 1983. 9 Grassy Swale data i.c from Riofiltration Phase II, unpublished. Large ponde and Small ponds are defined as follows: Large ponds Small ponds ---------- ----------- SA/SD > 1 GA/GD < 1 VB/VR > 1 VB/VR < 1 Overflow rate < 0.1 ft/hr Overflow rate > 0. 1 ft/hr Hydraulic racedence time Hydraulic resedence time > 14 days < 14 days Ley end: Data for grassy swales is 902 + NO3 rather than Kjeldhel Nitrogen f Lead removala were inferred from data uii iron, since lead behaves simialrly in water, and lead was below detection. x --I- 71 iuc IJ:l`ILl, - 121H HLH icy �U: 1' 6 Design Parameters for Detention Pond Water Quality Improvement (after Walker, 1986) . I. Pond surface area / Drainage surface area > 1% Fenton TP Site: Pond area = 0.57 acres (0.23 ha) , Total site area = 49. 6 acres (20 ha) 5A/SD = 1.1% II. Pond volume / Mean storm runoff volume > 1 Mean storm runnff volume = watershed area (ha) X runoff coefficient X mean storm size (cm) Rnntnn TP Site: Pond volume = 0.23 ha X 100 cm 2300 cubic meters Mean storm size = 1.22 cm Site runoff coefficient = 0.4 (40% impervious) Mean storm volume = 20 ha X .4 X 1.22 Cm 976 cubic meters VB/VR Ratio = 2300 cubic meters / 91b cubic meters 2. 36 III, overflow rate < 0.1 It/hr overflow rate _ mean runoff rate / pond surface area (mean storm size(cm) X runoff coefficient X drainage area(ha) ) / (mean storm duration(hr) X pond area(ha) ) Renton TP Site: Assumptions: Mean storm size = 1.22 cm Site Runoff Coefficient - 0.4 Masan storm duration = 20 hours overflow rate = (1.22 om X 0.4 X 20 ha) / (20 hr X n.23 ha) 2.12 cm / hr 0.07 ft / hr ( 1 ft - 30.48 cm) btr %r v♦ RUC ov:O( 1L:Pltl, - 1GiH FLH �tL PIU: IGUOI bU'I-1bU'U' ❑UIIJ rPJ'y IV'. Hydraulic detention time > 14 days for Sot Phoophorus removal. 100 X pond area(ha) X pond depth(m) / Drainage area X runoff coefficient x mean storm size / length of season (yr) Rentnn TP Site! Auuumptions: length of season - 9 mo = .7b yr Hydraulic residence time = 100(0.23 ha) (1 in) (0.66 yr) J 20 ha(0.4) (106 Cm) = 0.019 yr 7 days d: u SSP-24-'V1 IUt WV!bt 10:MtC - 12IH FLP- ItL NU: LdO,) fDU1-1JWJ mule POb References Cited in Letter Considerations for the Use of Wet Ponds for Water Quality Enhancement. 1989. Office of Water Quality, Metro, Seattle, WA 981U4. Martin, Edward H. and James L. Smoot. 1996. Constituent-load Changes in Urban Stormwater Runott Routed Through a Detention Pond-Wetlands System in Central Florida. U.S.Geological Survey, Water Resources Investigation Report 85-4310. Walker, William Jr. 1986. Phosphorus Removal by Urban Runoff Detention Basins. "Lake and Reservoir Management: Influcnccs of Nonpoint Source Pollutants and Acid Precipitation" 6th Annual. International symposium, North American Lake Management Society, Portland, Oregon. November 5 - 8, 1986. U9 Environmental Protection Agency, 1983. Results of the Nationwide Urban Runoff Program. Volume 1 - Final Report. Water Planning Division, US EPA, Washington D.C. 20460. �i SEP-2,1-191 TUE 09'52 ID'MEC - 12TH FLB TEL H0: (206) 60A-1900 i10l10 Pei �►M E T R 0 Munkipality of Metropolitan Seattle Exchange Building • 821 Second Ave. Seattle, WA 98104-1598 FACSIMILE TRANSMISSION COYEn SHEET DATE SENT: z-r a4 0 TRANSMITTED TO: w6-A4 L- -AR?--fra .I S TRANSMITTED FROM: r_�a�F k(name) (mac stop) Telephone No.: FAX NUMBER FOR .ENVIRONMENTAL COMPLIANCE AND RIGHT OF WAY: (206) 684-1-900 NO.OF PAGES TRAN9MITTED: (Including cover sheet) COMMENTS: ; . z r 1 I:MF.TR0 Municipality of Metropolitan Seattle Exchange Building • 821 Second Ave. • Seattle, WA 98104-1598 CI1Y OF RENTCN RECEIVED September 17 , 1991 SEP 1 71991 Ms. Lynn Guttmann CUSTOMER SERVICE Director of Public Works Public Works Department City of Renton 200 Mill Avenue South Renton, Washington 98055 Metro Regional Treatment Plant Enlargement III Drainage Report and Request for Variance from Certain City Stormwater Management Requirements Dear Ms. Guttmann: As you know, as a condition of Metro's construction permit for Phase A of Enlargement III, Metro must identify how it will comply with the City's stormwater regulations. We have been working closely with Randall Parsons, City of Renton Stormwater and Wastewater Engineering Supervisor, to develop a stormwater management system to meet this condition. We have developed a system that is consistent with the goals of the City's stormwater regulations and protective of water quality. The program, which utilizes wetponds and swales, is described in detail in the enclosed drainage report prepared by Brown and Caldwell, consulting engineers. In order to implement this program, however, it will be necessary to obtain a variance from certain technical requirements in the City' s stormwater regulations. The City stormwater regulations provide that you or your representative may request such a variance from the Hearing Examiner. See Renton Municipal Code (RMC) 4-22-16. By this letter, we ask that you or Randall Parsons formally request such a variance from the Hearing Examiner. We understand that Randall Parsons has obtained a hearing date with the Hearing Examiner for October 1, 1991. We hope that the formal request to the Examiner can be made as soon as possible. Our reasons supporting this variance request are obtained in the enclosed variance application. In summary, strict compliance with certain provisions of the drainage regulations will create undue hardship and prohibit Metro from implementing its proposed stormwater management system. See RMC, Section 4-22-16 (A) . Metro Regional Treatment Plant September 17 , 1991 Page Two Thank you for your continued cooperation. Please contact me at your earliest convenience if you have any questions or if we need to discuss these issues further. Sincerely, Greg Manager Manager, Environmental Compliance JFS:gje Enclosures cc: Mr. Randall Parsons, City of Renton Mr. Paul Forsander, City of Renton Ms. Gerrie Jackson, Metro L/gj91691 CITY OF RENTON Planning/Building/Public Works Department Earl Clymer, Mayor Lynn Guttmann,Administrator 6PJ� 555I � y1 September 17, 1991 SEP 17 1991 Gerrie Jackson CITY OF RENTON METRO Engineering Dept. 821 -2nd Ave, M/S 122 Seattle,WA 98104 SUBJECT: Variance from Chapter 22 Storm/Surface Water Drainage for Metro Plant Expansion, Phase III SA;SM;SP-040-91 Dear Mr. Jackson: The date of Tuesday, October 1, 1991, at 9:00 a.m., has been set for a variance hearing to review the above-referenced matter. The hearing, before Mr. Fred Kaufman, Renton Hearing Examiner, will be held in the Council Chambers on the second floor of City Hall, Renton,Washington. The applicant or representative(s) of the applicant is required to be present at the public hearing. A copy of the staff report will be mailed to you one week before the hearing. If you prefer to make other arrangements to receive the staff report, please contact Kathleen Childers, 277-5582, or Sandi Seeger, 277- 5581. If you have any questions, please call 235-2550. Sincerely, Donald K. Erickson, AICP Zoning Administrator cc: Jack Warburton Randall Parsons, Spvsr Brown&Caldwell Engineers Storm/Wastewater 1232 E Crockett City of Renton Seattle, WA 98102 Vicky Ranier METRO 821 -2nd Ave, M/S 130 Seattle, WA 98104 William Horne 14703 SE 100th St Renton, WA 98059 Perry Weinberg Prestron Thorgrimson Shidler Gates& Ellis Attorneys at Law 5400 Columbia Center, 701 Fifth Ave Seattle,WA 98104-7078 hexW/DKE/k 200 Mill Avenue South - Renton, Washington 98055 CITY OF RENTON Planning/Building/Public Works Department Earl Clymer, Mayor Lynn Guttmann,Administrator September 16, 1991 Gerrie Jackson, Permit Coordinator METRO Right-of-Way/Property Department M.S. 122 Exchange Building 821 2nd Ave. Seattle, WA. 98104 SUBJECT: DRAFT APPLICATION FOR VARIANCE TO STORMWATER DRAINAGE CODE FOR METRO RENTON TREATMENT PLANT ENLARGEMENT III Dear Ms. Jackson, i The following are my recommended revisions to your draft variance application letter. (1) A cover letter to Lynn Guttmann, Administrator, Planning/Building/Public Works Department, should accompany and formally request consideration of this variance submittal. I. INTRODUCTION (2) You may wish to include my title following my name "Stormwater and Wastewater Utility Engineering Supervisor". H. REGULATORY BACKGROUND (3) Insert " the Core and Special Requirements contained in section 1.2 and 1.3 of chapter 1, and" in the first paragraph prior to"chapters 3, 4, and 5 of the ... III. SUMMARY OF PROPOSED STORMWATER PROGRAM (4) Insert " for new impervious surfaces subject to vehicular use or storage of chemicals" prior to ", ie.," Also, I think this last portion of text from", ie.,"on, confuses the issue. IV. VARIANCE REQUEST (5) The Core and Special Requirements in Chapter 1 to which the variance relates were not referenced. From my reading of the variance request letter I think the following is the list of Core and Special Requirements and the relevant variance request issues: 200 Mill Avenue South - Renton, Washington 98055 Page : 2, Metro Variance for Enlargement III: September 16. 1991 o Core Requirement# 1: Discharge at the Natural Location To allow interim discharge of stormwater runoff through the Treatment Plant for treatment and discharge directly to Puget Sound through the Effluent Transfer System rather than to the Green River; to allow permanent discharge of stormwater from the water quality design storm treated by large wetponds, and rare emergency relief flows, into the P-1 Channel for control by the P-1 pump plant rather than to the Green River. o Core Requirement#3: Runoff Control To allow interim discharge of stormwater runoff through the Treatment Plant for treatment rather than on-site biofiltration facilities for all of the new impervious surface areas subject to vehicular use or storage of chemicals. To allow some new areas of impervious surface subject to vehicular use or storage of chemicals to not have biofiltration treatment on a permanent basis, but to instead provide wetpond water quality treatment up to the water quality design storm event for most of the site's new and existing impervious surface subject to vehicular use or storage of chemicals. o Core Requirement #4: Conveyance System To allow the use of a pump system for stormwater conveyance along with a variance from the standard size criteria for a pump storage facility (wet-well). o Special Requirement. Special Water Quality Controls To allow interim discharge of stormwater runoff through the Treatment Plant for treatment and discharge directly to Puget Sound through the Effluent Transfer System rather than treatment by a wetpond for the new impervious surface areas subject to vehicular use or storage of chemicals. (6) The last sentence in the middle paragraph " In short, .... " is not needed nor could we approve a variance on this basis. We can only review and approve variances to requirements that have been specified not " any and all sections of the KCSWDM necessary to implement its proposed stormwater system". (7) The discussion under" D. Variance from ..." is not clear to me. I think the points to be made are that while not all the new impervious surface areas subject to vehicular use or storage of chemicals will receive biofiltration treatment, all of the new and most of the existing stormwater runoff for the site's new and existing impervious surface subject to vehicular use or storage of chemicals plant will receive treatment from the wetponds up to the water quality design storm event, and that the wetponds will be three times the size required by the KCSWDM. V. CONCLUSION (8) 1 would prefer that you strike the last sentence in the first paragraph and instead to state in the cover letter to Lynn Guttmann that you have coordinated preparation of this variance request with me and that I have generally supported the concepts put forth on the basis that the Enlargement III Stormwater Program will meet or exceed the stormwater facility performance specified by the KCSWDM requirements. (9) 1 also recommend that you qualify cost savings as "benefits to, and/or in the public's interest" which they are. This usually not the case for private developments seeking variances from the stormwater codes which the variance criteria was primarily written for. Page : 3, Metro Variance for Enlargement III: September 16, 1991 Please call me at 277- 5548 if you have any questions. Very truly urs, a I Parson , P.E., Uti ity Engineering Supervisor Stormwater an Wastewater Utility Section METROVAR.DOC cc Rick Butler,Project Engineer,Brown and Caldwell Perry Wienberg,Counsel,Preston/Thorgrimson/Shidler/Gates and Ellis MUNICIPALITY OF METROPOLITAN SEATTLE (METRO) ENLARGEMENT III OF METRO TREATMENT PLANT AT RENTON APPLICATION FOR VARIANCE PURSUANT TO 4-22-16 SEPTEMBER 16, 1991 I. INTRODUCTION The Municipality of Metropolitan Seattle (Metro) has prepared a stormwater management program consistent with the City of Renton (City) drainage requirements and with condition 7 of the building permit issued by the City for Phase A of the Metro treatment plant Enlargement III project in Renton. The program is described in detail in the Drainage Report prepared by Brown and Caldwell, consulting engineers (attached) . Metro worked closely with Randall Parsons, City of Renton Stormwater and Wastewater Utility Engineering Supervisor, to develop this program. The program, which utilizes wetponds and swales, is consistent with applicable drainage requirements and provides adequate protection of water quality. In order to implement the program, however, Metro must obtain a variance from certain technical requirements. This document constitutes Metro's application for variance from these requirements. II. REGULATORY BACKGROUND The Renton Code requires the preparation of a drainage plan in conformance with the Core and Special Requirements contained in sections 1. 2 and 1. 3 of chapter 1, and chapters 3 , 4 , and 5 of the King County Surface Water Design Manual (KCSWDM) and City of Renton standard drafting and design requirements. Renton Municipal Code (RMC) 4-22-9. A variance from drainage requirements may be obtained as follows: The Director [of the Department of Public Works] or [her] representative may recommend to the Hearing Examiner a variance from the requirements of this Ordinance when, in [her] opinion, undue hardship may be created as a result of strict compliance with the provisions of this Ordinance. RMC 4-22-16 (A) . To grant such a variance request, the Examiner must find: 1. That there are special physical circumstances or conditions affecting said property such that the strict application of the provisions of this Ordinance would deprive the applicant of the reasonable use or development of his land; 2 . That the variance is necessary to insure such property the rights and privileges enjoyed by other properties in the vicinity and under similar circumstances; and 3 . That the granting of the variance will not be detrimental to the public welfare or injurious to other property in the vicinity. RMC 4-22-16 (A) (1) -(3) . The Examiner' s decision must consider the following criteria: 1. Capacity of downstream facilities; 2 . Acceptability of receiving bodies of water; 3 . Possibility of adverse effects of retention; 4 . Utility of regional retention facilities; and 5. Capability of maintaining. RMC 4-22-16 (B) . III. SUMMARY OF PROPOSED STORMWATER PROGRAM The proposed stormwater facilities will consist of biofiltration swales located adjacent to newly constructed roadways and parking lots, a pump station to lift and transport stormwater, and a series of oversized wetponds. The pump station and wetponds will have three times the capacity required in the KCSWDM. These facilities are designed to treat stormwater associated with all new impervious surfaces subject to vehicular use or storage of chemicals. Under the proposed stormwater program, stormwater will continue to drain to the Green River outfall manhole west of the Administration Building and just east of Monster Road. The existing system will be augmented with a pump station at the outfall manhole. This pump station is necessary to lift stormwater flows to wetpond facilities that will be located on the surface. Flows in excess of the pump capacity, which is 3- times the capacity required by the KCSWDM, will overflow into the Green River via the existing 120-inch outfall diffuser. Stormwater will be pumped to wetponds for water quality treatment. The wetponds will be a series of ponds located near existing wetlands on-site. The ponds will be terraced to allow 2 gravity flow between the wetponds. Ultimately, the wetponds will drain to the P-1 Channel. This avoids the need for another pumping station to discharge flows to the Green River. The stormwater pump station is planned to be constructed as part of the Phase A constrction contract, and is planned to be in operation by the summer of 1992 . The biofiltration swales and wetpond facility are scheduled to be constructed during Phase B, which is planned to begin in January 1993 . In the interim--while these facilities are being designed and constructed--the pump station will pump stormwater flows to the headworks of the wastewater plant for treatment and discharge to Puget Sound via the Effluent Transfer System (ETS) . Stormwater pumping will be redirected to the wetpond facility when it becomes operational. IV. VARIANCE REQUEST In order to implement this stormwater management design, Metro requests a variance from the following requirements of the KCSWDM to avoid undue hardship: • Core Requirement 1 : Discharge at the Natural Location To allow interim discharge of stormwater runoff through the treatment plant for treatment and discharge directly to Puget Sound through the ETS rather than to the Green River. To allow permanent discharge of stormwater from the wetponds, and rare emergency relief flows, into the P-1 Channel rather than to the Green River. Stormwater discharged to the P-1 Channel will be controlled by the P-1 pump plant, which is a component of a regional Stormwater facility. • Core Requirement 3 : Runoff Control To allow interim discharge of stormwater runoff through the treatment plant for treatment rather than providing on-site biofiltration facilities for all of the new impervious surface areas subject to vehicular use or storage of chemicals. To allow some new areas of impervious surface subject to vehicular use or storage of chemicals to not have biofiltration treatment on a permanent basis, but to instead provide wetpond water quality treatment up to the water quality design storm event for most of the site ' s new and existing impervious surface subject to vehicular use or storage of chemicals. • Core Requirement 4 : Conveyance System To allow the use of a pump system for stormwater conveyance along with a variance from the standard size criteria for a pump storage facility (wet-well) . 3 • Special Requirement 5: Special Water Quality Controls To allow interim discharge of stormwater runoff through the treatment plant for treatment and discharge directly to Puget Sound through the ETS rather than treatment by a wetpond for the new impervious surface areas subject to vehicular use or storage of chemicals. This request is made in order for Metro to implement its proposed stormwater system. To the extent these four requirements reference or incorporate other sections of the KCSWDM, Metro requests a variance from those sections as well. Each of the four requirements listed above is discussed in detail below. A. Core Requirement #1 (Discharge at Natural Location) : Core requirement #1 provides that All surface and storm water runoff from a proposed project that proposes to construct new, or modify existing drainage facilities must be discharged at the natural location so as not to be diverted onto, or away from the adjacent downstream property. KCSWDM 1. 2 . 1. Metro requests a variance from this section in order to allow stormwater from the site to drain to the P-1 Channel, rather than to the Green River. Historically, the P-1 Channel (Springbrook Creek) was the natural drainage location for stormwater emanating from the site now occupied by Metro's treatment facilities. The railroad tracks located west of the site (and installed long before Metro arrived) created a physical barrier to drainage to the Green River. After Metro' s facilities were first constructed, natural drainage of the site continued to be generally toward the P-1 Channel. When Oakesdale Avenue was constructed to the north and east of the site, drainage to the P-1 Channel was blocked for portions of the site, and a pump had to be installed to control water that backed up on the site and started to threaten existing facilities. The KCSWDM provides that where diversion of stormwater "will correct an existing problem, " the diversion should be considered as a variance. KCSWDM 1. 2 . 1. The present stormwater system drains approximately 60 percent of Metro's property (49.7 of 84 . 5 acres) to the Green River via the existing stormwater system. Approximately 20. 1 acres (24 percent) drain from open vessels, sludge dewatering, and septage areas on site and are run through the plant for treatment and discharge to Puget Sound via the effluent transfer system (ETS) . Approximately 6 acres (7 percent) drain directly to the P-1 Channel. Finally, 7 .72 acres (8 percent) drain to on- 4 site wetlands and 1. 16 acres (1 percent) drain from Oakesdale avenue to the City of Renton stormwater system. Metro's existing stormwater sewer system discharges stormwater to the Green River via a 120-inch outfall diffuser. This outfall diffuser was the original discharge point for treated wastewater effluent from the plant. When the ETS and Puget Sound outfall were completed in 1987, the Green River outfall was retained for use as a stormwater outfall. From a hydraulic standpoint, discharge to the P-1 Channel will not increase substantially the flows predicted to occur in the channel. Metro' s proposed stormwater system will discharge up to 4 . 5 cubic feet per second (cfs) of treated stormwater to the P-1 Channel. Flows in excess of this amount will continue to drain to the Green River, except under flood conditions. When the Green River is at flood stage, emergency relief sewers will drain surcharged storm sewers to the P-1 Channel. The magnitude of these emergency relief flows has not been quantified. However, the fact that Metro ' s stormwater system did not reach capacity during the recent extreme storms of January 1991, January 1990 or November 1990, suggests that emergency relief flows should be small. Preliminary modeling results show that flows in the P-1 Channel at the forebay of the P-1 pumping plant will be approximately 789 cfs during a "two-year" storm event and 1518 cfs during a 11100-year" storm event. The 4 . 5 cfs of stormwater predicted to be contributed from Metro's stormwater facilities would result in an insignificant (about 0. 6%) increase during a two-year storm. In short, the downstream facilities of the P-1 Channel offer sufficient capacity to accommodate Metro' s stormwater flows. Moreover, discharge to the P-1 Channel, rather than to the Green River, is consistent with the directives of the Green River Management Agreement (July 18, 1985) , entered by King County, and the Cities of Renton, Tukwila, Kent, and Auburn. While that agreement permits the discharge of additional stormwater flows to the Green River, it encourages that those flows be controllable, and it prohibits discharge of stormwater flows when the river is at flood stage. By discharging stormwater to the P-1 Channel, Metro's stormwater flows are subject to control at the P-1 pump plant and make use of this regional retention facility. Under Metro's proposal, no stormwater flows will be discharged to the Green River when it is at flood stage. Finally, if Metro were not allowed to discharge to the P-1 Channel, treated stormwater flows would have to be conveyed from the proposed wetponds back to the Green River. This would involve either gravity flow or pumping through a separate conveyance system or through the existing stormwater sewer system. Either approach presents a number of potential problems. First, gravity flow back to the Green River may be difficult when the Green River is at flood stage. Discharge to the Green River 5 • is also prohibited when the river is at flood stage. Second, if the existing stormwater system is used to reconvey flows back to the Green River, the capacity of the system to handle stormwater will be displaced by accommodating treated stormwater flows. Third, construction of a separate conveyance system would be difficult and expensive. If pumping were required as part of that conveyance system, that new pump station would itself require a variance from the KCSWDM. Under any of these approaches, discharge to the Green River would cause undue hardship and expense. The alteration of the original drainage (which used to go to the P-1) , and the difficulties and expense involved in reconveying treated stormwater flows from the wetponds to the Green River, constitutes special physical circumstances that warrant a variance from Core requirement #1. The variance is necessary to ensure that Metro can implement the preferred stormwater treatment system--wetponds (see below) --at the site. The variance will not be detrimental to the public welfare or injurious to other property in the vicinity because it will provide stormwater treatment consistent with the requirements of the KCSWDM, discharge rates to the P-1 Channel are insignificant, and discharge above the P-1 pump plant allows flows to be controlled by that regional retention facility. Metro also requests a variance from Core requirement #1 for interim discharge of stormwater to the treatment plant during the period that the new stormwater control facilities are being constructed. That variance request is discussed in more detail below. B. Core Requirement #3 (Runoff Control) : Core requirement #3 provides that Proposed [projects must] provide runoff control through a combination of peak rate runoff control facilities and on-site biofiltration measures . . . . KCSWDM 1. 2 . 3 . This requires, under certain circumstances, that wetponds or wetvaults be used to provide stormwater treatment. While Metro will implement wetponds as part of its permanent stormwater system, Metro will provide interim treatment of stormwater by running it through the treatment plant. That interim system will operate during the period that the new stormwater facilities are being constructed. In addition, as a condition of the Building Permit issued by the City for Metro' s Phase A site preparation work, the City required the following: No asphaltic or concrete roadways shall be installed on the project site until a storm water drainage design (including collection/conveyance, detention if required, water quality facilities and technical 6 information report) has been designed, submitted to the City of Renton, approved by the City, and constructed. (Italics added) . Metro requests that this condition be modified, and a variance from the KCSWDM requirement for wetponds be granted, to allow Metro to handle stormwater flows by running them through the treatment plant during the interim period between the time the stormwater pump station facilities are constructed and wetponds, swales, and related water quality facilities are completed. The proposed pump station must be constructed before the roads are built near the Administration Building, because the pump station will lie directly beneath the entrance off of Monster Road. These roads are scheduled to be constructed (including paving) early on during Phase A. While constructing the pump station, Metro proposes to install a pipeline from the pump station to the treatment plant influent structure. That would provide an interim stormwater treatment system that would be in place before many of the roads are completed. That interim system would treat stormwater by running it through the treatment plant. Metro's proposed "final" stormwater treatment system (with the wetponds and swales) will take considerable time to complete. That system involves using as part of its conveyance system a water line across Metro's property that is currently in use. Before that water line can be used, a substitute line must be constructed. That will not occur until later in the construction phasing. Allowing for interim treatment during plant construction will also allow Metro to work to integrate the wetponds into the landscaping and grading work planned for Phase B. It will also allow Metro to evaluate designs for the wetponds that combine the wetponds, the existing wetlands, and Metro' s Arts Program. Metro asks, therefore, that it be granted approval to provide interim stormwater treatment by running stormwater through the treatment plant until the wetponds are completed during Phase B of the construction project. This approval requires a variance from Core requirements 11 and #3 , and from Special Requirement #5 (below) . Granting the variance and modification to Building Permit Condition No. 7 is in the public interest, because interim treatment of stormwater by running it through the plant will provide optimal treatment of stormwater flows. This treatment will be employed only until the new stormwater facilities are constructed and available for use. To require Metro to construct all these facilities during the initial phase of the project would cause undue hardship, because (among other things) it would require the construction of new conveyance lines rather than using existing (but not yet abandoned) lines. 7 i Metro is also requesting a variance from that portion of Core requirement #3 that requires "on-site biofiltration facilities. " That variance is discussed below in section D. C. Core Reouirement #4 (Conveyance System) Core Requirement #4 provides that Pump systems (includes the pumps, force mains, electrical equipment, structures and appurtenances) are not allowed on storm drain systems in King County. A variance (see section 1.4) from this requirement . . may be requested. Any pump system (is required to meet certain] minimum conditions. . . . KCSWDM 1. 2 . 4 . Metro is seeking a variance to allow pumping for two reasons: 1) in order to implement the KCSWDM's preferred method of water quality treatment--wetponds--and, 2) to utilize the existing and extensive system of underground piping at the site. The existing site contains an underground stormwater sewer system. The network of underground pipes was originally designed to allow stormwater to drain by gravity to the Green River. For hydrologic reasons at the site, the sewer pipes are located relatively deep underground. The outfall manhole (the confluence of the stormwater sewer system before discharge to the Green River) is located about 26 feet below existing grade. A pump system is required to lift the stormwater flows from this manhole to the wetponds located on the ground surface. The pump will be designed and operated in accordance with Metro standard specifications. If Metro cannot obtain a variance to pump the stormwater, then it likely would have to construct a large underground wetvault at the location of the outfall manhole. This would deprive Metro from the reasonable use and development of the property because the area that would be needed to construct a wetvault is currently dedicated to future sewage treatment purposes. In addition, the construction of a wetvault would: not be consistent with the KCSWDM's preference for wetponds, itself require a variance, and would be very costly. Because the requested variance would allow Metro to implement the preferred method of water quality treatment, it will not be detrimental to the public welfare or injurious to other property in the vicinity. The KCSWDM specifically states that a variance for a pump system may be requested so long as the pump system is consistent with certain specified conditions. See KCSWDM 1.2 .4. Metro ' s proposed pump system complies with conditions 1, 2, 4, 5, and 6. Condition 3 requires that the pump system have a storage facility sized to hold 25 percent of the total volume of runoff. This storage facility is similar to a wetvault discussed above, and presumably is required to provide a degree of safety for the pump 8 station and the stormwater conveyance system in the event that the pump fails. Metro's proposed pump system accounts for pump failure without the need for a wetvault. The safety and integrity of the pump station is provided by dual pumps, an isolation gate, an overflow weir, emergency relief sewers, a 24-hour a day on-site maintenance staff, and 180, 000-gallon storage volume in the wet pit where the pump system is located. Metro believes that these measures are consistent with condition 3 for pump systems in section 1.2.4. Construction of a wetvault in addition to these measures would deprive Metro of its reasonable use and development of its property as discussed above. Metro therefore requests that its proposal be deemed to satisfy condition 3 so that a variance can be issued for the pump system. D. Special Reauirement #5 (Water Ouality Controls) : Special requirement 15 provides that IF a proposed project will construct more than 1 acre of impervious surface that will be subject to vehicular use or storage of chemicals [and certain other requirements are met] THEN a wetpond meeting the standards described below shall be employed to treat a project's runoff prior to discharge from the site. A wetvault or water quality swale . . . may be used when a wetpond is not feasible. KCSWDM 1.3 . 5. As noted above, Core requirement 13 also requires runoff control using "on-site biofiltration measures. " KCSWDM 1.2.3. These sections require that runoff from new impervious surfaces receive on-site biofiltration, if they are subject to vehicular use or storage of chemicals. While Metro' s proposed stormwater plan does not meet some of the technical requirements for on-site biofiltration, the plan does satisfy the intent of that requirement by providing equivalent or better treatment to runoff from all pervious and impervious surfaces, new and old. Metro will provide on-site biofiltration treatment by constructing bioswales adjacent to new roadways and parking lots where sufficient pervious area is available. Local bioswales will serve about 33% of all new impervious surfaces that are subject to vehicle use or chemical storage, and well over 50% of the net increase in impervious surfaces requiring biofiltration. Treated effluent from the bioswales will drain to the stormwater sewer system. Runoff from the remaining new impervious roadways, parking areas, and chemical storage surfaces will receive treatment, along with runoff from existing surfaces, via the oversized wetpond facility. Under Metro's proposed stormwater program, the total area of impervious surfaces (subject to vehicular use or 9 chemical storage) that will receive treatment will be about three times as much as required by the KCSWDM. The proposed project will construct about 3. 8 acres of new impervious roadways and parking lots but will only increase the site's roadway and parking lot impervious surfaces by about 2 . 0 acres, for a total of 12 acres after Enlargement III. Most of the proposed new roadways and parking lots are either reconstructions (realignments) of old surfaces or are located with portions of the existing site with little or no pervious area (e.g. grassland) . Also, the new impervious areas requiring on-site biofiltration are not contiguous but are remotely separated from one another, and thus, runoff from these new areas cannot practically be collected and treated separate from the existing areas. Thus, providing on-site biofiltration to only the new impervious surfaces requiring treatment is logistically difficult. While runoff from all of the new impervious surface areas (roadways and parking lots) will not receive on-site biofiltra- tion, stormwater runoff from all of the new and most of the existing roadways and parking lots will receive treatment from the proposed wetponds. Stormwater flows up to the water quality design storm event will be pumped to the wetpond facility and the wetponds will be three times the size required by the KCSWDM. Metro anticipates that it can demonstrate that the proposed oversized wetpond facility, which will be three times the minimum area and volume required by special requirement 15, KCSWDM 1. 3 . 5, together with locally constructed bioswales, will provide equivalent or better treatment than a minimum sized wetpond facility and a single bioswale. This is based on the fact that pollutant removal efficiency in bioswales and wetponds is a function of detention time. Over time, it is anticipated that an equivalent or greater mass of pollutants will be removed by the oversized wetpond facility and local bioswales than by a minimum required wetpond facility and biofiltration facility. V. CONCLUSION Metro requests a variance from Core requirements #1 (discharge at the natural location) , 13 (runoff control) , and #4 (conveyance system) , and from Special requirement #5 (special water quality controls) , and related requirements of the KCSWDM in order to implement the stormwater management system set out here and in the drainage report. This variance will enable Metro to utilize wetponds, the preferred method of water quality required by the KCSWDM. It will also provide an opportunity to investigate enhancing the on-site wetlands in the vicinity of the proposed wetpond facility. For the reasons discussed above, this request meets the criteria for a variance. Strict compliance with the KCSWDM will create undue hardship for Metro by precluding use of an existing 10 D pipeline, unreasonably restricting the use of significant portions of Metro' s property that is dedicated for future sewage treatment purposes, and by requiring enormous additional expense, which is contrary to the public interest. The variance request is not detrimental or injurious to the public welfare or other property owners in the vicinity. Finally, this variance request will not adversely affect the capacity of the P-1 Channel. In fact, discharge to the P-1 Channel, with its regional retention facility, is consistent with applicable policy for regulating flows to the Green River. Metro respectfully requests that the requested variances be granted. 11 " METRO Municipality of Metropolitan Seattle Exchange Building • 821 Second Ave. • Seattle,WA 98104-1598 • (206)684-2100 September 19, 1991 n Ms. Lynn Guttmann Renton Public Works Department ;FP )2� 1991 Municipal Building ", 200 Mill Avenue South OF R-tNTON Renton, WA 98055 C1 Engineering Dear Ms. Guttmann: This letter is to provide technical back up for Metro's letter of September 16, 1991, requesting a variance to some of the specific requirements of the King County Surface Water Design Manual (KCSWDM) which has been adopted by Renton for stormwater management. Metro's proposed stormwater management system for the Renton Treatment Plant site was developed to meet the water quality objectives of the KCSWDM, and provide water quality performanace equivalent to that expected from the core requirements. Metro's proposed design involves less reliance on grassy swales than specified by the core requirements, but compensates by oversizing the on-site detention wet pond. As explained in our application, this flexibility is sought because Metro is providing treatment for existing runoff as well as for the proposed expansion. The existing site drainage pipes are placed very deep, which will necessitate pumping the water to the surface for treatment. Because of site constraints and the opportunity to use an existing line for stormwater conveyance, biofiltration would be very costly to implement over the entire site. In brief, the system we are proposing involves providing biofiltration for exterior roadways and some parking areas, a constructed wetland for an isolated parking area, and treatment of the remaining stormwater in an oversized wet detention pond. About 2/3 of the new impervious area, as well as drainage from the existing site, would be treated via the detention pond. Metro believes an oversized wet pond designed to treat the full 2 year-24 hour storm flow will perform significantly better than one sized for 1/3 that flow, as the KCSWDM currently requires. Data to support this argument are taken from the Nationwide Urban Runoff Program (NURP) , which studied the performance of wet detention ponds throughout the country (USEPA, 1983) . Walker later analyzed the NURP data, relating water quality performance to engineering design criteria (Walker, 1986) . Four specific design predictors were used in the EPA and Walker reports. They are as follows: Ms. Lynn Guttman September 19, 1991 Page 2 1) The ratio of pond surface area to the surface area of the drainage, SA/SD; 2) The ratio of pond volume to the mean storm runoff volume, VB/VR; 3) The surface overflow rate during the mean storm; and 4) Mean hydrualic residence time. In addition, pond configuration and the prevention of short circuiting are important considerations, although no quantitative indices have been developed. Each of these areas will be addressed in turn. Attachments provide numerical backup for the stated removal rates of the proposed pond. Ratio of pond surface area to surface area of the drainage. In general, the pond surface area should be about 1% of the contributing drainage area to achieve good pollutant removal efficiency. Modeling done for Metro in support of the Lake Sammamish Management Plan suggests that with a pond depth of about 1 meter, almost 90% removal of total suspended solids (TSS) could be expected. NURP data shows that detention ponds with surface areas greater than 1% of the watershed area achieved TSS removals of from 60% to 90%. Removal of heavy metals was also superior to that seen in smaller ponds. The proposed detention pond at the Renton site has a surface area of 1. 1% of the site drainage area. Ratio of pond volume to mean storm runoff volume. Ponds having the ratio of pond volume to mean storm runoff volume greater or equal to 1 show better removal efficiencies than ponds in which the ratio is less than one. Metro's proposed pond has a ratio of 2 . 3 , which corresponds to TSS removals of 60% to 90% in the NURP data. Surface overflow rate. This design predictor is the ratio of the mean storm runoff rate to the pond surface area. In the NURP study, ponds with overflow rates less than about 0. 1 ft/hr performed best in terms of TSS and metal removals. Metro's proposed pond has an overflow rate of 0. 07 ft/hr. Ms. Lynn Guttman September 19, 1991 Page 3 Hydraulic residence time. The longer storm flows are detained, the greater treatment provided, both for TSS as well as for the nutrients nitrogen and phosphorus. In part, nutrient removal in wet ponds is due to biological activity in the water column, a process which is time dependent. Walker estimates that for phosphorus removal of up to 80%, a detention time in excess of 14 days is required. For about 50% phosphorus removal, detention times of 7 - 14 days would be required. TSS removals of 60% to 80% have been seen with detention times of between 6 and 7 days, according to data from NURP and Martin & Smoot (1986) . As currently designed, with an active pool volume of about 1 meter, the proposed pond has a detention time of 7 days. Since the receiving waters (P-1 channel and Green River) are not particularly phosphorus sensitive in the reaches downstream of the Treatment Plant, detention times of greater than 7 days would not seem necessary. However, if determined otherwise, it would be possible to achieve a 15 day detention time by increasing the pond depth to 2 meters. Pond configuration. A laboratory scale model studied by Horner and Kortenhof (1987) , found that long, narrow pond configurations with two cells achieved longer residence times than single cell configurations. The proposed detention pond design provides three cells, as per the KCSWDM, and a very elongate configuration. Use of three cells and the long, narrow configuartion serves to maximize the travel path of storm water introduced into the pond, and increase the residence time over that projected on the basis of engineering parameters alone. The attached Table indicates a range of expected annual pollutant removal effectiveness for Metro's proposed enlarged pond size, and the smaller pond size required in the Manual. The Table also gives preliminary data about the removal efficiencies of biofiltration swales. (Biofiltration data was collected this summer as part of an inter-agency project to monitor the pollutant removal effectiveness of grassy swales, and is as yet unpublished. ) The expected pollutant removal performance is given as a range to indicate the variability seen in different parts of the country with different pond treatment systems. In general, a much higher annual average level of pollutant removal is expected from large ponds with design characteristics as described previously. Ms. Lynn Guttman September 19, 1991 Page 4 These data indicate that with an enlarged detention pond sized as proposed, water quality performance equal to or better than that expected from a smaller pond plus biofiltration can be achieved. Metro appreciates your willingness to consider our request for flexibility in the manner the requirements and water quality objectives of the KCSWDM can be met. If you have questions about the data presented, please contact me at 684-1551 or Louise Kulzer, at 684-2063. Additional background information can be found in Metro's publication "Considerations for the Use of Wet Ponds for Water Quality Enhancement. " References cited in this letter are appended. Very truly ours, ohn F. Spencer Director Water Pollution Control Department JFS: lkk Enclosures References Cited in Letter Considerations for the Use of Wet Ponds for Water Quality Enhancement. 1989. Office of Water Quality, Metro, Seattle, WA 98104. Martin, Edward H. and James L. Smoot. 1986. Constituent-load Changes in Urban Stormwater Runoff Routed Through a Detention Pond-Wetlands System in Central Florida. U. S.Geological Survey, Water Resources Investigation Report 85-4310. Walker, William Jr. 1986. Phosphorus Removal by Urban Runoff Detention Basins. "Lake and Reservoir Management: Influences of Nonpoint Source Pollutants and Acid Precipitation" 6th Annual International Symposium, North American Lake Management Society, Portland, Oregon. November 5 - 8, 1986. US Environmental Protection Agency, 1983 . Results of the { Nationwide Urban Runoff Program. Volume 1 - Final Report. Water Planning Division, US EPA, Washington D.C. 20460. Pollutant Removal Performance of Large and Small Detention Ponds and Grassy Swales Pollutant Percent Removal Observed Large ponds Smaller ponds Grassy swales (average of 4 storms) Total dissolved 60 - 90% neg. - 30% 80% solids (TSS) Total phosphorus 3 - 80% neg. - 30% 5% Total Kjeldahl nitrogen neg - 60% neg. - 20% neg. Total lead 80 - 90% 10 - 60% 70% # Total zinc neg. - 70% 0 - 10% 60% Notes: Detention pond data is from NURP, USEPA, 1983 . Grassy Swale data is from Biofiltration Phase II, unpublished. Large ponds and small ponds are defined as follows: Large ponds Small ponds ----------- ----------- SA/SD > 1 SA/SD < 1 VB/VR > 1 VB/VR < 1 Overflow rate < 0. 1 ft/hr Overflow rate > 0. 1 ft/hr Hydraulic resedence time Hydraulic resedence time > 14 days < 14 days Legend: ^ Data for grassy swales is NO2 + NO3 rather than Kjeldhel Nitrogen # Lead removals were inferred from data on iron, since lead behaves simialrly in water, and lead was below detection. Design Parameters for Detention Pond Water Quality Improvement (after Walker, 1986) . I. Pond surface area / Drainage surface area > 1% Renton TP Site: Pond area = 0.57 acres (0.23 ha) Total site area = 49 . 6 acres (20 ha) SA/SD = 1. 1% II. Pond volume / Mean storm runoff volume > 1 Mean storm runoff volume = watershed area (ha) X runoff coefficient X mean storm size (cm) Renton TP Site: Pond volume = 0.23 ha X 100 cm = 2300 cubic meters Mean storm size = 1. 22 cm Site runoff coefficient = 0.4 (40% impervious) Mean storm volume = 20 ha X .4 X 1. 22 cm = 976 cubic meters VB/VR Ratio = 2300 cubic meters / 976 cubic meters = 2 . 36 III. Overflow rate < 0. 1 ft/hr Overflow rate = mean runoff rate / pond surface area _ (mean storm size(cm) X runoff coefficient X drainage area(ha) ) / (mean storm duration(hr) X pond area(ha) ) Renton TP Site: Assumptions: Mean storm size = 1.22 cm Site Runoff Coefficient = 0.4 Mean storm duration = 20 hours Overflow rate = (1.22 cm X 0.4 X 20 ha) / (20 hr X 0.23 ha) = 2 . 12 cm / hr = 0.07 ft / hr ( 1 ft = 30. 48 cm) IV. Hydraulic detention time > 14 days for 80% Phosphorus removal. = 100 X pond area(ha) X pond depth(m) / Drainage area X runoff coefficient X mean storm size / length of season (yr) Renton TP Site: Assumptions: length of season = 9 mo = .75 yr Hydraulic residence time = 100 (0. 23 ha) (1 m) (0. 66 yr) / 20 ha(0.4) (106 cm) = 0. 019 yr = 7 days THE CITY OF RENION DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS n RENTON. WASHINGTON 98055 - 2189 -+r PHONE 235-2631 FAX 235-2541 FAX TRANSMITTAL DATE: ` 9 TO:FROM.- SUBJECT: Number of pages excluding cover sheet: THE CITY OF RENTON _ DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS RENTON. WASHINGTON 98055 - 2189 PHONE: 235-2631 FAX: 235-2541 i FAX TRANSMITTAL DATE_ 116 A / TO: L/i✓ FROM: a �s SUBJECT: /Aj � Vid�lAAI�� Number of pages excluding cover sheet: i SENT BY PRESTON. THORGRIMSON 9-16-91 :10:59,4M SEATTLE- 206 233 2541 :# 1/10 f 5400 Columbia Center FRES ON 701 Fifth Avenue THORGRIMSON Seattle,WA 98104-7078 SHIDLER GATES & ELLIS Telephone: (2W 623-7580 ATTORNEYS AT LAW Facsimile: (206)623-7022 TELE OPIER COVER PAGE (p ( ! (Date) Cp r To: R From: "1 (I.Vividual 'A r 0 p Q y U _ No. of Pages: it ( om any) ^(Infeludi[`n Cover Page) IX -a�7, ClientMMatter No.: O�la 7 - (Telecopy No.) ClientlMatter Name (CoMirmaton No.) If you do not receive all of the pages, please contact:`0 Telecopy o erator. (2 )6 -7580, SAL 5540 �u Name: rEtt.:' COivMENITS: The information wntained in this facsimile is confidential and may also be attorney-privileged. The information is intended only for the use of the individual or entity to whom it is addressed. If you are not the intended recipient,or the employee or agent responsible for delivering it to the intended recipient,you arc hereby notified that any use,dissemination,distribution or copying of this communication is strictly pro- hibitcd. It you have received the facsimile in error,please immediately notify us by a oollect telephone call to(206)623-7580,and return the original message to us at the address above via the U.S.Postal Service. Thank you. PTSOE-02M(Rr Scam SENT BY=PRESTON. THORGRIMSON 9-16-91 : 10:59AM SEATTLE- 206 235 2541 :# 2/10 j 7-, hJI MUNICIPALITY OF METROPOLITAN SEATTLE (METRO) ENLARGEMENT ITT OF METRO TREATMENT PLANT AT RENTON APPLICATION FOR VARIANCE PURSUANT TO 4-22-16 SEPTEMBER 16, 1991 � �a fe,,w-4-- I. INTRODUCTION The Municipality of Metropolitan Seattle (Metro) has prepared a stormwater management program consistent with the City of Renton (City) drainage requirements and with condition 7 of the building permit issued by the City for Phase A of the Metro treatment plant Enlargement III project in Renton. The program is described in detail in the Drainage Report prepared by Brown and Caldwell, consulting engineers (attached) . Metro worked closely with Randall Parsons, who is responsible for stormwater management at the City, to develop this program. The program, which utilizes wetponds and swales, is consistent with applicable drainage requirements and provides superior protection of water quality. In order to implement the program, however, Metro must obtain a variance from certain technical requirements. This document constitutes Metro 's application for variance from these requirements, �,� II . REGULATORY BACKGROUND e � " �M 5 The Renton Code r quires the preparation of a drainage plan in conformance with chapters 3 , 4, and 5 of the King County Surface Water Design Manual (KCSWDM) and City of Renton standard drafting and design requirements. Renton Municipal Code (RMC) 4- 22-9. A variance from drainage requirements may be obtained as follows: The Director [of the Department of Public Works] or (her] representative may recommend to the Hearing Examiner a variance from the requirements of this Ordinance when, in [her] opinion, undue hardship may be created as a result of strict compliance with the provisions of this Ordinance. RMC 4-22-16(A) . To grant such a variance request, the Examiner must find: 1. That there are special physical circumstances or conditions affecting said property such that the strict application of the provisions of this Ordinance would deprive the applicant of the reasonable use or development of his land; SENT BY PRESTON. THORGRIMSON - 9-16-91 :11 :OOAM SEATTLE- 206 235 2541 :# 3/10 2 . That the variance is necessary to insure such property the rights and privileges enjoyed by other properties in the vicinity and under similar circumstances; and 3 . That the granting of the variance will not be detrimental to the public welfare or injurious to other property in the vicinity. RMC 4-22-16 (A) (1) - (3) . The Examiner's decision must consider the following criteria: 1. Capacity of downstream facilities; 2 . Acceptability of receiving bodies of water; 3 . Possibility of adverse effects of retention; 4 . Utility of regional retention facilities; and 5. Capability of maintaining. 5, V TN%. �sv RMC 4-22-16 (5) . �,pr y1� r �„ �o ® C/' �. III . SUMMARY OF PROPOSED STORMWATER PROG The proposed stormwater facilities will consist of biofiltration swales located adjacent to newly constructed roadways and parking lots, a pump station to lift and ''transport stormwater, and a series of oversized wetponds. The p p station and wetponds will have three times the capacity requir din the KCSWDM. These facilities are designed to treat stormw ter Associated with all of the Enlargement III Pacilities✓ . � ar v air Elate 'on j;3 rimary -- and — er ' Under the proposed stormwater program, stormwater will continue to drain to the Green River outfall manhole west of the Administration Building and just east of Monster Road. The existing system will be augmented with a pump station at the outfall manhole. This pump station is necessary to lift stormwater flows to the wetpond facilities located on the surface . Flows in excess of the pump capacity, which is 3-times the capacity required by the KCSWDM, will overflow into the Green River via the existing 120-inch outfall diffuser. stormwater will be pumped to wetponds for water quality treatment. The wetponds will be a series of ponds located near existing wetlands on-site. The ponds will be terraced to allow gravity flow between the wetponds. Ultimately, the wetponds will drain to the P-1 Channel. This avoids the need for another pumping station to discharge flows directly to the Green River. 2 SENT BY:PRESTON. THORGRIMSON : 9-16-91 :11 :OOAM SEATTLE- 206 233 2541 :# 4/10 The pump station is planned to be constructed as part of the Phase A construction contract, and is planned to be in operation by the summer of 1992 . The biofiltration swales and wetpond facility are scheduled to be constructed during Phase B, which is planned to begin in January 1993 . In the interim--while these facilities are being designed and constructed--the pump station will pump stormwater flows to the headworks of the wastewater plant for treatment and discharge to Puget Sound via the Effluent Transfer System (ETS) . Stormwater pumping will be redirected to the wetpond facility when it becomes operational. IV. VARIANCE REQUEST In order to implement this stormwater management design, Metro requests a variance from the following requirements of the KCSWDM to avoid undue hardship: • 4 . 3. 1 (conveyance system design and analysis) regarding drainage to P-1 Channe2� a r �r • 4 . 3 . 4 (pipe systems) utilizing pump station • 4 . 6. 3 (biofiltratio facilities) regarding use of localized swales • 4 . 6.2 (wetponds and wetvaults) or Building Permit Condition No. 7 , for diverting flows to treatment plant on interim basis. This request is made in order for Metro to implement its proposed stormwater system. To the extent these four requirements reference or incorporate other sections of the KCSWDM, Metro requests a variance from these rgquirements as well. In short, e ro is reques ng a variance from any and all sections of the KCSWDM necessary to implement its proposed stormwater system. j Each of the four requirements listed above is discussed in detail below. A. Variance From KCSWDM 4.3 .1 For Drainage to the P-1 Channel The KCSWDM provides generally that stormwater conveyance systems and treatment facilities should be designed in a manner that emulate[s] the natural conveyance system to the extent feasible. Inflow to the system and discharge from the system should occur at the natural drainage points as determined by topography and existing drainage patterns. 3 SENT BY:PRESTON. THORGRIMSON : 9-16-91 ;11 01AM SEATTLE- 206 235 2541 ;# 5/10 KCSWDM, section 4 . 3 . 1. Metro requests a variance from this section in order to allow stormwater from the site to drain to the P-1 Channel, rather than to the Green River. Historically, the P-1 Channel (Springbrook creek) was the natural drainage location for stormwater emanating from the site now occupied by Metro 's treatment facilities. The railroad tracks located west of the site (and installed long before Metro arrived) created a physical barrier to drainage to the Green River. After Metro's facilities were first constructed, natural drainage of the site continued to be generally toward the P-1 Channel. When Oakesdale Avenue was constructed to the north and east of the site, drainage to the P-1 Channel was blocked for portions of the site, and a pump had to be installed to control water that backed up on the site and started to threaten existing facilities. The present stormwater system drains approximately 60 percent of Metro ' s property (49 .7 of 84 .5 acres) to the Green River via the existing stormwater system. Approximately 20. 1 acres (24 percent) drain from open vessels, sludge dewatering, and septage areas on site and are run through the plant for treatment and discharge to Puget Sound via the effluent transfer system (ETS) . Approximately 6 acres (7 percent) drain directly to the P-1 Channel. Finally, 7. 72 acres (8 percent) drain to on- site wetlands and 1 . 16 acres (1 percent) drain from Oakesdale avenue to the City of Renton stormwater system. Metro's existing stormwater sewer system discharges stormwater to the Green River via a 120-inch outfall diffuser. This outfall diffuser was the original discharge point for treated wastewater effluent from the plant. When the ETS and Puget Sound outfall were completed in 198 , the Green River outfall was retained for use a stormwater outfall . From a hydraulic standpoint, discharge to the P-1 Channel will not increase substantially the flows predicted to occur in the channel. Metro' s proposed stormwater system will discharge up to 4 . 5 cubic feet per second (cfs) of treated stormwater to the P-1 Channel. Flows in excess of this amount will continue to drain to the Green River, except under flood conditions. When the Green River is at flood stage, emergency relief sewers will again drain surcharged storm sew s to the P-1 Channel . The magnitude of these emergency 71. f flows has not been quantified. However, that fac that Metro' s stormwater system did not reach capacity during h event extreme storms of January 1991, January 1990 No �1. r 1990, suggests that emergency relief flows sh ld be P,P` � Preliminary modeling results show that flows in the P-1 Channel at the forebay of the P-1 pumping station will be approximately 789 cfs during a "two-year" storm event and 1518 cfs during a 11100-year" storm event. The 4 . 5 cfs of stormwater predicted to be contributed from Metro' s stormwater facilities would result in an insignificant (about 0 . 5%) increase. In 4 SENT BY:PRESTON. THORGRIMSON : 9-16-91 :11 02AM SEATTLE- 206 235 2541 :# 6/10 short, the downstream facilities of the P-1 Channel offer sufficient capacity to accommodate Metro's stormwater flows. Moreover, discharge to the P-1 Channel, rather than to the Green River, is consistent with the directives of the Green River Management Agreement (July 18, 1485) , entered by King County, and the Cities of Renton, Tukwila, Kent, and Auburn. While that agreement permits the discharge of additional stormwater flows to the Green River, it encourages that those flows be controllable, and it prohibits discharge of stormwater flows when the river is at flood stage. By discharging stormwater to the P-1 Channel, Metro ' s stormwater flows are subject to control at the P-1 pump station and make use of this regional retention facility. Under Metro' s proposal, no stormwater flows will be discharged to the Green River when it is at flood stage. Finally, if Metro were not allowed to discharge to the P-1 Channel, it would have to install another pump station in order to transport treated stormwater from the wetponds to the Green River. Requiring that additional pump station would cause undue hardship and also would itself require a variance from the KCSWDM. The alteration of the natural drainage on the site, from the original drainage to the P-1 Channel to the current drainage to the Green River, constitutes special physical circumstances that warrant a variance from the requirements of 4 .3 . 1. The variance is necessary to ensure that Metro can implement the preferred stormwater treatment system--wetponds (see below) --at the site. The variance will not be detrimental to the public welfare or injurious to other property in the vicinity because it will provide stormwater treatment that exceeds the requirements of the KCSWDM. B. Variance from KCSWDM 4 . 3 . 4 For Utilizing Pump Station The KCSWDM provides that pump systems are "allowed only by variance. " a= sections 4.3 .4 and 1. 2 . 4 . Metro is seeking a variance to allow pumping for two reasons: 1) in order to implement the KCSWDM's preferred method of water quality treatment--wetponds--and, 2) to utilize the existing and extensive system of underground piping at the site. The existing site contains an underground stormwater sewer system. The network of underground pipes was originally designed to allow stormwater to drain by gravity to the Green River. For hydrologic reasons at the site, the ®ewer pipes are located relatively deep underground. The depth of the ground cover at the outfall manhole (the confluence of the stormwater sewer system before discharge to the Green River) is about 26 feet. A pump system is required to lift the stormwater flows to the wetponds located on the ground surface. The pump will be designed and operated in accordance with Metro standard specifications. 5 SENT BY PRESTON. THORGRIMSON ; 9-16-91 ;11 =024Nf SEATTLE- 206 235 2541 :# 7/10 If Metro cannot obtain a variance to pump the stormwater, then it likely would have to construct a large underground wetvault at the location of the outfall manhole. This would deprive Metro from the reasonable use and development of the property because the area that would be needed to construct a wetvault is currently dedicated to future sewage treatment purposes. In addition, the construction of a wetvault would not be consistent with the KCSWDM' s preference for wetponds and would require a variance, and would be very costly. Because a variance would allow Metro to implement the preferred method of water quality treatment, it will not be detrimental to the public welfare or injurious to other property in the vicinity. The KCSWDM specifically states that a variance for a pump system may be requested so long as the pump system is consistent with certain specified conditions. KCSWDM 4 . 3 .4 . Metro's proposed pump system complies with conditions 1, 2 , 4 , 5, and 6. condition 3 requires that the pump system have a storage facility sized to hold 25 percent of the total volume of runoff. This storage facility is similar to a wetvault discussed above, and presumably is required to provide a degree of safety for the pump station and the stormwater conveyance system in the event that the pump fails. Metro 's proposed pump system accounts for pump failure without the need for a wetvault. The safety and integrity of the pump station is provided by dual pumps, an isolation gate, an overflow weir, emergency relief sewers, a 24-hour a day on-site maintenance staff, and 180, 000-gallon storage volume in the wet pit where the pump system is located. Metro believes that these measures are consistent with condition 3 . Construction of a wetvault in addition to these measures would deprive Metro of its reasonable use and development of its property as discussed above. Metro therefore requests that its proposal be deemed to satisfy condition 3 so that a variance can be issued for the pump system. C. Variance from XC5WDM 4 . 6. 2 . or from Building Permit Condition No. 7 . For Diverting Flows To Treatment Plant On Interim Basis KCSWDM 4 . 6.2 requires, under certain circumstances, that wetponds or wetvaults be used to provide stormwater treatment. While Metro will implement wetponds as part of its permanent stormwater system, Metro will provide interim treatment of stormwater by running it through the treatment plant. That interim system will operate during the period that the new stormwater facilities are being constructed. As a condition of the Building Permit issued by the City for Metro's Phase A site preparation work, the City required the following: 6 SENT BY:PRESTON. THORGRIMSON ; 8-16-31 :11 03AM SEATTLE- 206 235 2541 ;# 81,10 No asphaltic or concrete roadways shall be installed on the project site until a storm water drainage design (including collection/conveyance, detention if required, water quality facilities and technical information report) has been designed, submitted to the City of Renton, approved by the City, and constructed. (Italics added) . Metro requests that this condition be modified, or a variance from the KCSWDM requirement for wetponds be granted, to allow Metro to handle stormwater flows by running them through the treatment plant during the interim period between the time the stormwater pump station facilities are constructed and wetponds, swales, and related water quality facilities are completed. The proposed pump station must be constructed before the roads are built near the Administration Building, because the pump station will lie directly beneath the entrance off of Monster Road. These roads are scheduled to be constructed (including paving) early on during Phase A. While constructing the pump station, Metro proposes to install a pipeline from the pump station to the treatment plant influent structure. That would provide an interim stormwater treatment system that would be in place before many of the roads are completed. That interim system would treat stormwater by running it through the treatment plant. Metro's proposed "final" stormwater treatment system (with the wetponds and swales) will take considerable time to complete. That system involves using as part of its conveyance system a water line across Metro' s property that is currently in use. Before that water line can be used, a substitute line must be constructed. That will not occur until later in the construction phasing. Allowing for interim treatment during plant construction will also allow Metro to work to integrate the wetponds into the landscaping and grading work planned for Phase B. It will also allow Metro to develop a design for the wetponds that combines the wetponds, the existing wetlands, and Metro ' s Arts Program. Metro asks, therefore, that it be granted approval to provide interim stormwater treatment by running stormwater through the treatment plant until the wetponds are completed during Phase B of the construction project. Granting the variance or modification to Building Permit Condition No. 7 is in the public interest, because interim treatment of stormwater by running it through the plant will provide optimal treatment of stormwater flows. This treatment will be employed only until the new stormwater facilities are constructed and available for use. To require Metro to construct all these facilities during the initial phase of the project would cause undue hardship, because (among other things) it would 7 SENT BY PRESTON. THORGRIMSON ; 9-16-31 :11 :04ANI SEATTLE- 206 235 2541 ;# 9/10 require the construction of new conveyance lines rather than using existing (but not yet abandoned) lines. D. Variance from KCSWDM 4. 6. 3 For Using Localized Swales KCSWDM requires that bioswales be sized to meet certain technical requirements. According to these requirements, Metro must treat all stormwater after it has been collected and routed to the outfall manhole. A bioswale properly sized to treat runoff from all tributary surfaces requires a peak flow rate capacity of 10. 2 cfs, a width of 50 feet, and a length of 245 feet. Wetpond facilities would have to be sized for a peak flow rate of 1.5 cfs, a water surface area of 8200 square feet and an active pool volume of 210, 000 gallons. In operation, the pump station would pump stormwater runoff from the outfall manhole to the biofiltration swale at a rate of 10. 2 cfs. After biofiltration, flows in excess of 1. 5 cfs would be discharged directly to a receiving stream while the wetpond facilities would provide treatment to 1. 5 cfs. Metro requests a variance from these biofiltration technical requirements because they create undue hardship for Metro. They require a pump station sized to capture and pump 10. 2 cfs. This would preclude the possibility of using the existing water line (which will be abandoned during Phase B) to convey stormwater flows to the wetpond facility because it is not sized to accommodate 10 . 2 cfs. The pump station also would require an additional source of emergency power. As a result, designing and constructing a pump station and pipeline to meet the technical biofiltration requirements would be extremely expensive. Moreover, constructing a 245 foot X So foot bioswale will unreasonably restrict Metro's use and development of its property. A variance will not be injurious or detrimental to the public welfare or other property in the vicinity because Metro has proposed an alternative biofiltration approach that it believes is at least as protective of water quality. Metro's proposed method of providing the required biofiltration is to construct bioswales adjacent to new roadways and parking lots where sufficient pervious area is available and to pump stormwater from the outfall manhole to "oversized" wetpond facilities. Local bioswales will serve about 33% of over 50% of the net increase in impervious road surfaces. Treated effluent from the bioswales will drain to the stormwater sewer system. Stormwater runoff from the rest of the site will receive equivalent biofiltration treatment via an "oversized" wetpond facility. Metro anticipates that it can demonstrate that the proposed oversized wetpond facility, which will be three times the minimum area and volume required by Section 1.3.5 of the KCSWDM, together with the locally constructed biofiltration swales, will provide equivalent or better treatment than a minimum-sized wetpond facility and biofiltration facility. This contention is based on the fact that pollutant removal efficiency 8 SENT BY:PRESTON. THORGRIMSON : 9-16-91 ;11 :04AM SEATTLE- 206 235 2541410/10 in bioswales and wetponds is a function of detention time. Over an entire year, it is anticipated that an equivalent or greater mass of pollutants will be removed by the oversized wetpond facility and local bioswales than by a minimum required wetpond facility and biofiltration facility. The pump station capacity will be 4 . 5 cfs which is three times the peak storm runoff rate. This is also nearly equal to the average runoff rate for the two year, 24-hour storm. A 12- inch city water line that will be abandoned under Phase A will be used to pump stormwater to the wetpond facility. New additional pipe will be required to connect the abandoned pipeline to the pump station and the wetponds. Emergency power to the pump station can be provided by an existing power feed near the dechlorination facility. As noted previously, the preferred site for the oversized wetpond is near the wetlands. V. CONCLUSION Metro requests a variance from sections 4 . 3 . 1, 4 . 3 . 4 , 4 . 6. 3 , 4 . 6.2 , and related requirements of the KCSWDM in order to implement its proposed stormwater management system. This variance will enable Metro to utilize wetponds, the preferred method of water quality required by the KCSWDM. It also would provide enhancement opportunities for the on-site wetlands in the vicinity of the proposed wetpond facility. f-7C- JUe ro s- understanding that the City' s stormwater supervisor fully supports this variance request. In addition, for the reasons discussed above, this request meets the criteria for a variance. Strict compliance with the KCSWDM will create undue hardship for Metro by precluding the use of an existing pipeline, by unreasonably restricting significant areas of property dedicated to future sewage treatment purposes, and by requiring enormous additional expense. The variance request is not detrimental or injurious to the public welfare or other proper_owners in the vicinity. Finally, this variance request will not adversely affect the capacity of the P-1 Channel. In fact, discharge to the P-1 Channel , with its regional retention facility, is consistent with applicable policy for regulating flows to the Green River. 9 R CITY OF RENTON =u Planning/Building/Public Works Department Earl Clymer, Mayor / Lynn Guttmann,Administrator August 20, 1991 Jerri Jackson METRO Exchange Building M.S. 821 2nd Ave. Seattle, WA. 98104 SUBJECT: GREEN RIVER MANAGEMENT AGREEMENT AND PUMP OPERATIONS PLAN Dear Ms. Jackson, As we discussed at our meetings and on the phone, please find enclosed a copy of the Green River Management Agreement and the Pump Operations Plan for you and your consultant's review with respect to the storm water management plan for the Phase III Renton Treatment Plant Expansion. We will be completing our review of the materials submitted late last week regarding the proposed water quality vault early next week. I will be on vacation until Tuesday, August 27, 1991, when you can call me at 277 - 5548 should you have any questions regarding these documents or our review of the materials submitted. very truly yours, /Randall Pa ons, Utility Engineering Supervisor tormwa r and astewater Utility Section METGPOP.DOC \� cc Gregg Zimmerman, P.E.,Plan Review Section Supervisor Ron Straka,Stormwater Utility Civil Engineer Enclosures 200 Mill Avenue South - Renton, Washington 98055 BA Brown and Caldwell �J Consultants 100 West Harrison Street Seattle Dal Washington 9 8119-418 6 (206)281-4000 FAX(206)286-3510 AU G 1 G 1991 CITY OF RENTON August 15, 1991 Engineering Dept, Mr. Paul Forsander Renton Program Manager Department of Planning/Building/Public Works 200 Mill Avenue South 14-5400-03 Renton, Washington 98055 3010201 Subject: Metro Regional Treatment Plant in Renton Enlargement III--Submittal of Drainage Design Development Report Dear Mr. Forsander: Enclosed are two copies of the draft Drainage Design Development Report for your review and comment. A separate official transmittal letter including a request for variances to technical items within the City's Stormwater Regulations will be issued by Metro. If you have questions regarding this report please call Rick Butler or myself at 281-4000. Very truly yours, BROWN AND CALDWELL A Jack Warburton Project Director JW:cp Enclosures cc: Mr. Rick Butler, Brown and Caldwell, Seattle Mr. Joe Fernandes, Metro, MS-107 Ms. Gerrie Jackson, Metro, MS-112 Ms. Vicki Renier, Metro, MS-131 fors-4/ce N a m Z N F � M w 8 w o C � yy H 4 Q W .J �ToRtxwaTEK FIRST OSH CHA1 1559, Ely ASS Tb STORMWXMK DtSC+4ARGE C}VNGCR MAXIMUM WS IN { STOP�MWATER .FIRST F1,US4 CHAt gE121 Ex�ST, MN !N/GReFNi S �1 Rk v E->Z AT t po y AR, o OV ERFLAW TO STORM WATER QISCNARGk ( F► aob Cl TDP of STRUCTURE ti MAY,[-MUTA wS y DAFFL� AT 10 ELEV TO KEEP V✓V % V AT50°6WKE SCUM v PLANT S D SysT�E,- 1N �10� VOLUME ( V' BAFFlE3 pPBRA�L{ N OA 14 ; . 4YPq� �wv D PUM PS , r rt N 2 GhTYa E R KArV EriT POOL_ ELF V �` 4- � ,.- P ll .� extST��4 GRAvtTy Lo SyST tnS Wv 0RAIN &ATEC, =y LOW CAPACVTy SO PUMPS • 3 12 o"� TO ro P�aur 96" FIANT PIPELINE TO GREEN RIVE R - � tr�FLu+✓M' INFLUENT COf`t't�ROL STI2UC7-uRE 3 lu3W z � , 3 $o z N O Bf7 Brown and Caldwell �J Consultants C r� NORTH SD A SYSTEM 8 116.0 MAN 4{O LE los. �\ 4 fyFoze:co,�r) M rCUM bhC IA LE FLE - 3 6AFFCf _. .. N V LT I GOTT'OM / DISCIA CIE ELQV 10$.D THIRD W V CHAMIS L✓ I0S.0 ' N VAULT b 4�W A..I 137,5� �4m slots loq-.o�. n 103.0---- iroe ZeAFFLE AT losA ? x ho4.b T2,t; Ib¢,0 50'/o VOLUME N HIGH ` c Io.o 8,4Ffs TaPEL�V1125 �. CAPACITY y N Low AT l0% o SD QVMP �ip_1 _ F CAPACITY VOWNIE o S� PUMP SECOND WV f - - _ FIRST WV o tlyy.D S HIGH Off ' �; �,♦ "'� CHATd6ER ! CHAMBER CAPAcmr - I _- t N VA_L)LT _ _ N V1tULT SD PUMP = I 0 il1 - - - 6eTrori i - - aloS,D tos.o IbS.Oy STORMWRTE 'rOP 112,5 DISCHARGE / \� M i. - - - - - - - ---- - - GNAMCiER I j _U-- BAFFIE•i I 161.0 ly AT 10% I/ �; x cAcacm I eI_UMI_ , , o EXISTIFJG / `° S/ p SoPUntP x SECOND WV EFFW6kT i°zto �' FI R$T WV C•HAM6F o g" CHAM 'UEP� 5 VAULT ,y dUA1CTI6N Ios.v 3 4 g VAULT STRllCTU E c 3 r to&o� � lo4,0 Sp MANHOLE/ � trlol� - To3:o Borram 1�p tow o 104.0 / 1 3 Q f'o N 1p3 b rOAFFL'�AT 104X.1 --507� VOLUME Q N J R Toe ELZV 112.6 1"a 105.0 a COW RaLLED SCUM SCUM PLAN AT olSfhuA Gt 8PF[LI (i0"PTOM ELE1 108D TVA IKE) VV V CHAMEER J C�/EfUI�T[ VAULT SCALE105Dy SOUrH SD ysrEri A SHEET NO. c� V7 1 _��Roj StormwateIr We Vo-glt I/� 19 JOB NUMBER SUBJECT GATE GEN-004-3/5/85 S� Brown and Caldwell �J Consultants c, r� I I �D SySi EM -S I�RAIII I I I II it ACCESS f�14t I 5uMp + I II II VU oT-V4 Pu P I I CovE R (Ty9 I I I STORt4 WATER, WET VAULT SID VomC tQv1Fm1 1, P�CCr~SS 1 I ACCEss Room I II � llgrcu�s I- I M F I WAT Q- I T3 rr1 N � �=' 'j � (TyP a4) I "1 FLOOV, I 51-Ox(�-O CCESS HATCLI A60YEi j �K x GATE o -c \ ;� i I r OPERATo W A?u EXiSTItcG I I I� STEM com>rCTlONS (Tv OF to) I MH - Dlv I I l 3("P WATEIPM GHT ACCI=S_S MANIdOLES I t t; PLAN Itc, . C)41 N I ELEVATION I i Su�►lR1j'umR �I n Node :`'" 111 I'��1 D 11 DYoj'A Suw 5 �0 RYOV� it Weav,S oe kycvI r—J co, VcoAWOL I �I-- 1 — -Tr - - - - - - - - S 5,D , SYSTEM aC) N 5�oO• S ! SHEET NO. 0l0201 W�y MT �rwtWo��21r wG� aC�v�� � I c� JOB NUMBER SUBJECT DATE GEN-004-3/5/85 W o Z M ~ O W O W_`YT p Z! W W Q t o �QVIPNtENY ACL�ss 1-iATCH d N R4R0 ST'DRIrn w AT`E.R WE-7 VA V t_T -�j EQVtPPv I ACCESS ROosq pEt?MhNENT GA7-E OPE>ZPtTO RS � 120 PE,RMAN ENT POOL 4 (T1P POOI WS EL6V � W W6 ELEV 1o9.o �Pv�,W 4IATCN cr` F) too D ,Jp�l m S � N THIRD WV lV . WET A0 S 30' S.Q S. WET VAVLT 30"SQ THIRD wv 3 CIlANt2 �� N INLEr .oP 13,LNGS i vL-ET 1 0PENINGS G4lRM(3£i2 IIO VA12I.T (j� 10 7 VPiSIlL __ Y Y —109,0— ® I _T ISgo .o� STORM ATER FIRST FLUS1-1 +CHAM12>E Io8.O� n5 I uo f36-T70K OF �_ LOW CAPACITY 103,0 SD, Pumps lo3.D— SCU M BAFFLEcz oo 1 S. WET VAUt_-r 24"SQ N. WET VAtJ LT C'RAl'N SLUICE GATES C1 0RAIN SLUICE GATES EXISTINC. 911 PLANT � � @ \ EMERGANC`( EFFLUENT ® N OTE Q o DUE To I.-oc4moN OF EXISTING 0 u 9G!' o PI.OI PtPELINE Mume,6 . CTION AA o om C2 MUSr BE* PILE sUPPORTZD SCALI= I If N 1 W Z N � o w w o = Z N w - i STORMWATER WET VAUI-T GATE OPERATORS 3 w lS(a •C m � ' uc�•o fl yN COMO�OLLED � 10V -PooL W.S. � 12�0 �1 o ET VA LT STORFL.pWTO ho ID9.a W 4a ' SQ PTS R R 3yPks5 eetefilF SLUtCEE LLOWpAPAr-M4 pm . 98,o GATS 98,0 � � 3 too Fa— eo cu 90 (Tw, SECTION 8 _ mU r �J p �� �� SCALE 1 "= 10f-�� �o N a m r N W =Lp, N Z W W r O d FLUSH ACCESS DOOR,; FOV STAtRwELLS � STORNtW/jTEFt J110. WE'T V ULT o ply �(atUtPMtNT lt- � x , EICCESS �J a) ROOM 12 ,[ U m U - I I S W ET VAULT. z� N -WETVA9LT rtts.5 �C Z0 3.5 N L LU C NP.N GONTRO�t Ep Cowrp 1-L, ;V STOFZM WATER OISCHARGE' GEP, �E? o p1SG41ARG6 ' ptsCkARG - 1I 0 Z W V BY? O EN ING1 , �_ G RAV mj ACCESS e 0NMA 5 0 �o' -- T S r \ -_ __ O . 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C 1n U:vq 1 to [ (A -o ko vw l,t 9G. r" }c r r. �, c, r I tA LUj e- Ua _( k au of �- FI C3 + RuOc% TLt a' LI�ECcin.� �tJe`E VO,U�_k 6,V-e- �ovpvco�F . 4-Z0 ,060 JOMVA.s CV S�D of e. "O ve )perW coo e__ V A IIroo l ct.-I&d 67S006 gct_NI s 0,, ,bve cke-0-A s6vne spc-ce , &_PPYoKI LVa L-c_I7 FG0f006 q�I( 1 Y ikAe-%A Yaty\ %bo s low Co act � `�,`' A10 to koq elevaA-ro" U2 , 0 j u,)e � VoLuM C6u -e_ uf.� Cute 05 . SGoutC9. , �c ��Y6Ce!c c�aca U+ wed vat�� a� va-�D J CU � l o u1e\r -[- u)e+ vain.4+ l e ve I 1 $ ASHEET /� NO. r . 9 3/NVMBE SUBJECT E GEN-004-3 5/85 BA Brown and Caldwell l/ Consultants y't V eta YPSI (Lk\res �fe a F OrCx 7 o V 4 60 K 46-e low Cap-( k puta,4?s , ((ljjs WOUJId ekAAr .`� S6Y%AA d,v'Cotr�a St1fi-kQ ttA (0 � QttrS � (bw . 7, TL, P_ UP ©peVc:{-rr,v. V)M loe �v e `I-wo eKit6 3o ( o 2' s OIL I a LI c-s fie wad ev S ut Ace e( evo,�ct---� IL, � ,e eKts�7" SD tucttA� olile , t s be ( o tk)J vo_LA s yS(InAA o peyo- kf,� exCAeed � � oPeY ~ . J I�v,� Cots.Gl, Ut,c c�t U tli {P,o �l�E VCt C c c ec„ o evQ� � u� �eUe� K�k� �red' . MOY-WOMw ( _e uJ,2+ vkui+ -C �Je o �ro_.�U leue( s wd p 5, ET NO. SiO� Ott- We-� VC Qce b e 4v � JOB TILM6 RE SUBJECT OA E GEN-004-3 5/85 l CITY OF RENTON MEMORANDUM DATE: August 14, 1991 TO: Gregg Zimmerman, P.E. Plan Review Supervisor 6178 FROM: Paul Forsander, Architect Project Manager 6167 SUBJECT: Renton Treatment Plan Site Preparation for Enlargement III Proposed Revision to Storm Water Design Schedule to Allow for City Reviews SA;SM;SP-040-91 Gregg: Please review the proposed revisions to Metro's draft schedule. Action Responsible Agency Date Complete Reports B&C Sept 27, 1991 NTP Final Design Metro Oct 8 Complete 40% Design B&C Dec 4 Review 40% Design City/Metro Dec 4-Dec 18 Complete 90% Design B&C Jan. 15, 1992 Review 90% Design City/Metro Jan 15-Feb 5 Submit for Permit Metro/B&C February 28 Permit Review City Mar 2-Mar. 23 Revise Design Metro/B&C Mar 23-April 6 Issue Permit City April 20 Contractor NTP Metro April 20 SCHEDULE DOC CITY OF RENTON )�\ MEMORANDUM .,, DATE: August 13 , 1991 c1� pF P Nfog pep. TO: File FROM: Gregg Zimmerman G 2 Plan Review Supervisor SUBJECT: Renton Treatment Plat Site Preparation for Enlargement IIIA, Conditions for Building Permit Issuance The following conditions will be written into the building permit and the construction permit for the above subject project: 1. The fill shown on grading plan drawings L114, L115, L119, L120, L121, L122 and L123 shall not be installed until the existing City water line beneath the proposed fill has been relocated out of the fill area. Design drawings at 1"=20' scale shall be prepared showing the relocated City water line. These plans must be submitted to the City and approved prior to issuance of a construction permit for the relocation of this water line. The relocated water line must be within a 151 wide easement dedicated to the City of Renton. 2. A separate construction permit will be issued by the City for the water main relocation described in Item 1. 3 . This permit does not include adjustments to fire hydrants shown on Drawings L120 and L123 . Plans must be submitted to the City of Renton and approved by the City prior to construction of this work. The City will issue a construction permit to authorize this work. 4. No fill or spoils shall be placed on the area designated as "Spoil Area 111 , on plan sheet G41, until the existing 12" City water main has been relocated, as described in item 1. METRO Bldg Permit Memo August 13 , 1991 Page 2 5. The 2" electrical conduit and entrance gate (Drawings G114 and G115) shall be installed a minimum of 5' away from the existing City water line. A note to this effect must be added to the drawings. 6 . The drawings shall incorporate profile and sectional views of the jacked casing pipe running beneath Monster Road. These drawings are subject to approval by the City of Renton prior to construction. 7 . No asphaltic or concrete roadways shall be installed on the project site until a storm water drainage design (including collection/conveyance, detention if required, water quality facilities and technical information report) has been designed, submitted to the City of Renton, approved by the City, and constructed. 8. All of the structural review comments of July 12, 1991 must be resolved to the satisfaction of Mahan & DeSalvo, Consulting Engineers and the City of Renton. 9. Work referenced on drawings G91-G97 inclusive must not be commenced until structural review is completed (see item 8) . 10. No excavation adjacent to existing structures may be commenced until structural review is completed (see item 8) . cc: Jim Hanson Dick Anderson Craig Burnell Jan Conklin Paul Forsander Ron Olsen Randall Parsons GAZ/tpG76 CONFERENCE REPORT NAME OF PROJECT: DATE OF CONFERENCE: PROJECT NO. TIME: (START) (END) NAME AND TITLE OF ORGANIZATION PHONE PEOPLE ATTENDING City of ( vi ``t 277- 6Zo7 CV l 27 8 Z 77 - 5s4f 2 l o Vt c! COMMENTS• SITE PREPARATION/PERIMETER LANDSCAPING I CONSTRUCTION AND BUILDING PERMIT STORMWATER CODE COMPLIANCE SCHEDULE Responsible Action agency Due date Drainage Design Development Report Submit draft report BC August 14 , 1991 to City City review and City of Renton August 21, 1991 comment Incorporate comments, BC August 28, 1991 finalize Variance Application Prepare variance BC August 16, 1991 application draft Review by Metro Metro/Perry August 23 , 1991 Weinberg Finalize and submit BC August 27, 1991 to City City review and City of Renton September 3, 1991 comment Incorporate comments, BC/Metro/Perry September 6, 1991 final to City Weinberg Hearing Examiner Notice of Hearing to City of Renton September , 1991 newspaper (Noon) it- Notice of Hearing Newspaper September ),T, 1991 published Hearing Examiner City of Renton September 16 , 1991 staff report Hearing Examiner City of Renton September 24 , 1991 hearing (9 : 00 a.m. ) Hearing examiner City of Renton October 8, 1991 decision SECOND DRAFT AUGUST 9, 1991 5400/s[ormcd/cp _Y z Responsible Action agency Due date Design/construction of drainage facilities Soils/groundwater BC September 27, 1991 investigation reports Notice to Proceed final Metro October 8, 1991 design 40 percent complete BC/Metro/City December 4, 1991 review of Renton Advertise pumps/ BC/Metro/City January 15, 1991 electrical equipment of Renton prepurchase 90 percent complete BC/Metro/City January 31, 1992 review of Renton 100 percent complete BC/Metro February 28, 1992 submittal Final review by City City of Renton March 13 , 1992 Issue construction City of Renton March 16, 1992 permit Finalize negotiation Metro March 13 , 1992 with Contractor Contractor Notice to Metro March 18, 1992 Proceed Finalize construction Contractor July 31, 1992 City of Renton final City of Renton August 7, 1992 inspection/project acceptance Issuance of final permit City of Renton August 12 , 1992 Contractor finalize site Contractor November 11, 1992 preparation/perimeter landscaping contract SECOND DRAFT AUGUST 9, 1991 5400/stotmcd/cp IF REVISIONS, ROUTED WITH �� PREVIOUS PLANS AND COMMENTS. GREEN NO. CITY OF RENTON BUILDING DIVISION PLAN REVIEW ROUTING SLIP J DATE APPLICANT: JOB ADDRESS: Z24 NATURE OF WORK: IL111,9C Pf=A-?Wl TO: Comments Due Comments Due FIRE PREVENTION BUREAU BUILDING CODE REVIEW STATER SYSTEMS ENERGY CODE � SEWER SYSTEMS STORM DRAIN SYSTEMS. TRANSPORTATION DIVISION PLANNING DIVISION OTHERS MECHANICAL Comments/suggestions should be provided in writing. Please provide comments to the Building Division by 5: 00 p.m. on above date. REVIEWING DEPARTMENT/DIVISION DpaIXII APPROVED APPROVED WITH CONDITIONS NOT APPROVED 771 A} W64�77TN cdNp/TTo?4 The,,qT 77`//r �7a1�� ui�9T/ 1z s0i('iRi/!/i9� �0f3ti!/77`, D 9a ?�W C l 7�V o r`lfF N7a N Tf` G/7 1 /�1YD �pdi4'ov0 /�i /5� /iYSyD DATE��I 11- 0fVDirec or Authorized 'Representative lnrev "rti 7 R IF REVISIONS, ROUTED WITH PREVIOUS PLANS AND COMMENTS. GREEN NO. CITY OF RENTON BUILDING DIVISION PLAN REVIEW ROUTING SLIP DATE APPLICANT: 2 2 t> 6e A �p JOB ADDRESS: 4`1Od 0i NATURE OF WORK: / z!L-, FI L t'J9/111) P- TO: Comments Due Comments Due FIRE PREVENTION BUREAU I BUILDING CODE REVIEW WATER SYSTEMS ENERGY CODE SEWER SYSTEMS STORM DRAIN SYSTEMS . I TRANSPORTATION DIVISION I PLANNING DIVISION I I OTHERS I I MECHANICAL Comments/suggestions should be provided in writing. Please provide comments to the Building Division by 5: 00 p.m. on above date. REVIEWING DEPARTMENT/DIVISION.��N(�IIL/fij APPROVED APPROVED WITH CONDITIONS NOT APPROVED �x vN(77Z VIE F�G�ir 7-,2 S- `/l /P��✓��ry �/S'Ch�i/�'c�� ('��T,s`c.�ir.U� l40kn f4�--RM17� 7HF C171, ic1/Z-6 410 yd �eA COA9cros OF Z�f��'r DATE IAI& _ Si atur o Dire or or Authorize Representative forms#2 1 rev CDVb1d022(2/13/90) 2_ `b p �( IF REVISIONS, ROUTED WITH R U'6 y6 PREVIOUS PLANS AND COMMENTS . GREEN NO. CITY OF RENTON BUILDING DIVISION PLAN REVIEW ROUTING SLIP DATE 7` ' PLICANT: OB ADDRESS : f 2 "goo � (4 ATURE OF WORK: ( — Q G 0: Comments Due Comments Due FIRE PREVENTION BUREAU BUILDING CODE REVIEW WATER SYSTEMS ENERGY CODE SEWER SYSTEMS STORM DRAIN SYSTEMS . TRANSPORTATION DIVISION PLANNING DIVISION OTHERS ( MECHANICAL omments/suggestions should be, provided in writing. 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I wnw n:y xm.f x.. -_ �JXIIIJM.J i Ix.21.4 ` II 07 1 1.14 x n.. 73 U xIn, xl .! s / X©� w XIn. I/ x,T+ ° 1 + 4 I mx• �J�''''y�� x D \ \ Xnas Xm.i1.2 x axr x,x] XIA.} x� -/ • ._�h xIM) —...GO %1 •Y,JC. % x � ., •kIM, 1I � 1 ��I' ,E.�V , X,n.} / y I I ,X IW I► • xme IV a xIMJ J xl J In. \ Q x n Cq F ` � IA1 , � � X,A, 'ol Ji '�'�I , +II',,1I • A� �• x > u ` MATCH LINE SEE DRABIND 6124 tM[ 4 ] INCHES 'g � AL IUl SCALE N 4 ♦ X —I IP nlav p JUL ti 1991 CITY OF RENTON July 2, 1991 Engineering Dept. OFFICE OF THE HEARING EXAMINER CITY OF RENTON REPORT AND DECISION APPLICANT: METRO WASTEWATER TREATMENT PLANT EXPANSION III File No: SA, SP-040-91 LOCATION: 1200 Monster Road S.W. SUMMARY OF REQUEST: Site Plan approval to expand facilities at the existing Metro Wastewater Treatment Plant and a Special Permit for excavation, grade and fill on subject expansion site. SUMMARY OF ACTION: Planning Division Recommendation: Approval, with conditions. PLANNING DIVISION REPORT. The Planning Division Report was received by the Examiner on June 4, 1991 PUBLIC HEARING: After reviewing the Planning Division Report, examining . available information on file with the application, and field checking the property and surrounding area, the Examiner conducted a public hearing on the subject as follows: MINUTES The hearing was opened on June 11, 1991 at 9:00 A.M. in the Council Chambers of the Renton Municipal Building. Parties wishing to testify were affirmed by the Examiner. The following exhibits were entered into the record: Exhibit #1 - Yellow File containing application, proof of posting and publication and other documentation pertinent to this request. Exhibit #2 - Vicinity Map Exhibit #3 - Existing site plan Exhibit #4 - Proposed site plan Exhibit #5 - Site sections south and east through middle of site Exhibit #6 - Site sections west from Oakesdale and south from Northern end of site Exhibit #7 - Conceptual Planting plan Exhibit #S - Expansion - Phase A Exhibit #9 - Expansion - Phase B Exhibit #10 - Expansion - Phase C Exhibit #11 - By reference - aerial Photo of site. Exhibit #12 (a) and (b) - Testimony from William Horne and maps for May Valley area. Exhibit #13 - By Reference - Memorandum of Agreement between the City and Metro Exhibit #14 - Gerri Jackson's Hearing Statement dated June 11, 1991. METRO WASTEWATER TREATMENT PLANT - Expansion III SA, SP-040-91 July 2, 1991 Page 2 Exhibit #15 - Letter of June 23, 1983 from Richard Houghton to Raymond Drebin. Exhibit #16 - Policy on Transportation Level of Service submitted by Clint Morgan. Exhibit #17 - Applicant's proposed revisions to recommended conditions. Due to the length of the hearing, below is only a summary of the testimony presented by all parties. The hearing opened with a presentation of the staff report by PAUL FORSANDER, Senior Planner, and his review comments follow. Planner Forsander used the zoning map and Comprehensive Plan to demonstrate compliance of this proposal with those city documents, and continued with a background review of the Metro Plant's inception in 1965 and continued growth and expansion needs to this point in time. This proposal will be the third expansion of the treatment plant; the total site is 84.5 acres with approximately 6 acres lying within the city's shoreline management district; and there are two wetlands of approximately 2 acres in size located in the northern portion of the site that will not be affected by this proposal (but will be protected by fencing and a 25 £t. wide buffer strip). Within the shoreline district there are slated to be improvements to the roadway, a trail is to be included adjacent to an existing security fence, extension of the chlorine contact channel, and two secondary clarifiers. Berming and landscaping will also take place within the shoreline area. Forsander noted screening and landscaping to soften the edges of the site and adjacent properties is of the utmost concern to the city. Access will be from Grady Way, Monster Road or Oakesdale Avenue SW. The interior landscaping proposed may be removed with future expansions to the site. The applicant feels they are creating a campus-like atmosphere for the site. The subject proposal will be completed in three stages: (1) perimeter grading and landscaping, site excavation, dewatering from 1991 - 1993; (2) 1993-1995 facility construction; (3) completion of interior landscaping, site clean-up and additional landscaping around the perimeter. Continuing, FORSANDER pointed out access to the site from Monster Road and Grady Way; noted there are adequate fire and police services available, sewers are available to serve the site and there are existing storm water drainage facilities. Storm water is collected and discharged into the Green River. He said Metro presented several alternatives for the site in the EIS and Metro has selected alternative #2. It should also be pointed out that the City and Metro have entered into a Memorandum of Agreement which addresses Metro's desire to begin construction in August, 1991 and the city's concerns over possible environmental impacts to the wetlands and environmental health. Under the terms of the Agreement Metro has committed to the implementation of certain mitigation measures and the City has agreed to try to expedite review of the necessary permits (MOA is Exhibit #13). Excavation for the facility will involve approximately 260,000 cu. yds of material. A soils analyses did not indicate contaminated soils, but if such are discovered later they would be transported and disposed of off-site. Dewatering of portions of the site will be necessary, and should groundwater prove to be contaminated it would be treated on-site and discharged through the effluent transfer system. If the groundwater is contaminated there may be a need for the city to supply between 2800 - 5000 gallons per minute (which is cause for concern as the city may not be able to provide that much water). Several roads within the site will be reconstructed to increase the turning radius for trucks, with an additional thirty- five parking spaces to be added along the existing chlorine contact channel. Criteria for site plan review for this expansion was presented. PLANNER FORSANDER said all proposed construction will take place within the existing boundaries of the wastewater treatment plant; Metro sells most of their methane gas to Washington National Gas and burns off what they do not sell; there is concern for the heron rookery and the chlorine storage building in the southeast corner of the site and $2.5 million dollars has been proposed to provide enhanced fire/safety protection to the plant in case of a hazardous material spill, chlorine leak or fire. Discussing site plan criteria, FORSANDER said the proposal complies with the Comprehensive Plan elements, the site is properly zoned, and the plan addresses land use regulations and all of the development standards, with minor modifications. A conceptual storm water plan has been submitted with a final plan to be submitted and reviewed by staff at a later date. An erosion control plan will be required prior to the issuance of the site plan permit. Lighting and odor control concerns have been addressed as well as hours of operation. Mitigation of impacts on the site are addressed, with berm landscaping and buffering for wetlands that could become a wildlife habitat; perimeter and interior landscaping will help the site be more compatible with surrounding uses; no traffic conflicts are expected; air quality and light will not be disrupted. The P-1 Channel and shoreline are of significant concern, and permits will need to be issued by the State of Washington as well as city staff. In his review of the special permit request for grade on the site, Planner Forsander said the grading is needed because there is no building construction until phase 3; there will be 260,000 cu. yds of excavation required to allow wastewater tank construction, about 100,000 cu. yds would be necessary METRO WASTEWATER TREATMENT PLANT - Expansion III SA, SP-040-91 July 2, 1991 Page 3 for permanent berms; 100,000 cu. yds will be stockpiled for perimeter landscaping and the remainder will be stockpiled for backfill for facilities construction after phase 2. A Transportation Management Plan has been agreed to by Metro which addresses traffic not only from construction but from employees; noise and hours of construction should not be a problem; and a tree cutting permit will be reviewed and approved administratively. At this point FORSANDER read the departmental recommendations into the record (copy attached). The Hearing Examiner called for testimony in support of the proposal from the applicant or their representative. Responding was GERRI JACKSON, Right-Of-Way Agent for Metro 821 Second Avenue, Mail Stop 122. Seattle 98104. Ms. Jackson reviewed the request including such topics as the proposed expansion of the wastewater treatment plant; upgrading of facilities to address odor control, increased landscaping, wetlands, wildlife habitat, mitigation measures, project history from inception, and the Memorandum of Agreement signed by Metro and city representatives. A copy of Ms. Jackson's hearing statement was entered as Exhibit #14. Further testimony supporting this request was received by JACK WARBURTON, Brown and Caldwell Consulting Engineers, 1232 East Crockett, Seattle 98102. In his testimony Mr. Warburton referenced the treatment plant on the aerial map entered as Exhibit #11 and explained the facilities and treatment process for the solid materials as well as foul air releases occurring as a result of the wastewater and sludge treatment. He addressed screening of materials, grit removal, primary treatment of settling materials, use of conversion tanks, the liquid stream expansion system, aeration tanks and their function, production and sale of methane gas, and the proposed expansion. WARBURTON pointed out which areas of the plant will be covered to address odor control and said Metro proposes to cover any of the process tanks to address air odors. Addressing points raised during previous testimony and from staff, he explained the storage process for chlorine, its transport by rail from the site, site expansion and public access (with the central area of the site to remain as open space); storm water drainage which empties into the Green River (with some of the water going to the treatment plant which ultimately ends up in Elliott Bay). Mr. Warburton pointed out landscaping that will be along Springbrook Creek, and the internal perimeter trail with the present fence line to remain. Traffic during construction will produce about 200-300 one-way truck trips per day with combined overall traffic from the site producing about 425 to 475 trips per day (of which 225-275/day will be construction trucks). An erosion control plan has been developed with the city. He said Metro will not require city water for use in the recharging process; there are five entrances to the site and security will be provided in the form of cameras and/or locked gates that will require the use of a card to gain entrance; and concluded stating the normal work schedule during construction will be five days a week, no weekends, during the hours of 7:00 AM to 7:00 PM. GERRI JACKSON again addressed the Examiner with a review of the EIS process and meetings held in that regard with staff and public. She referenced the herons/eagles at the site, proposed landscaping, additional mitigation requirements, the conveyance systems to be a part of this project contained in the signed Memorandum of Agreement and reviewed the agreed upon conditions. Commenting on general conditions from staff she said Metro is concerned about the inclusion of the Memorandum of Agreement as a condition of the permit as it has been determined that no significant impacts would occur that would require this type of mitigation. Because an agreement has been reached with the city to resolve differences based on lead-agency status through the MOA process rather than through an appeal of the SEPA process, the applicant feels the document is enforceable, and questions whether it should be placed as a condition on the site plan permit condition (condition l(a)) She recommended the condition be deleted. Other objections were raised to various conditions, and a copy of Metro's recommended condition revisions is attached. Further testimony on behalf of the applicant was received from VICKY RENIER. Metro, 821 Second Avenue, Mail Stop 130, Seattle 98104 who addressed the disbursement of funds for the wetlands. A breakdown of the 2.5M dollars under the Memorandum of Agreement consists of the disbursement of $500,000. by July 10, 1991 to the city. Metro and the city have four years to acquire the property - if the city acquires the property Metro will disburse to them the other 3M dollars. However, if Metro is not legally entitled to begin site preparation in mid-August, 1991 and if the city has become legally obligated to purchase the site within 12 months of executing the agreement, Metro will still disburse the 3.5M dollars in accordance with the subsection contained in the Agreement. The other funding mechanisms for the infrastructure improvements and improvements to sewer infrastructure would still be completed regardless of site preparation. Responding in opposition to this proposal was WILLIAM HORNE 14703 S E 100th Street, Renton 98059 as a representative for neighbors of May Valley. He disagreed with some of the terms of agreement contained in the Memorandum of Understanding regarding the May Valley interceptor. He feels the May Valley expansion is linked to the MOA and includes an acceleration of the May Valley interceptor. He said problems with flooding and erosion are of an emergency nature now. The Examiner advised him his concerns regarding the interceptor for May Valley are really not being addressed at this time - only the expansion of the wastewater treatment plant. The Examiner said the MOA for this proposal seems to indicate there will be a full environmental review which may or may I METRO WASTEWATER TREATMENT PLANT - Expansion III SA, SP-040-91 July 2, 1991 Page 4 not include an EIS, which then would present the citizens of the May Valley area an opportunity to express their concerns/desires to staff and the city council at that time. Exhibit #12 was entered at this time. JAMES GRAY, Assistant Fire Marshall for the city addressed the proposal and it's need to comply with Article 80 of the Uniform Fire Code relative to storage and use of hazardous chemicals. GRAY said it was the department's desire not to restrict hazardous materials to only chlorine and sulfur dioxide - he suggested discussions be left open between the Fire Department and Metro to review the hazardous chemicals now being used, and for Metro to submit a study (now in progress) so it may be determined what chemicals are used on the site, quantity, and their transport and security needs. It is necessary that this site comply with Article 80, and if Article 80 requires more than what is being proposed than the site would be required to comply with the existing requirements. Referring to security measures to be taken and the need to notify the Fire Department upon knowledge of any shipment to or from the treatment plant - Gray said this will have to be further discussed with Metro to finalize the process to be used. He said a 24 hour notice to fire officials on movement of chemicals would be desirable but probably not practical. Responding for the Water Utility Division of the Public Works Department was ABDUL GALFOUR responding to concerns of site dewatering and the possibility of contaminated water being released into the Effluent Transfer System (ETS) which could contaminate the city's drinking water. If contaminated water was evident, the city would have to provide water to the site in an amount of approximately 2800-5000 gallons per minute/24 hours a day, and it was questioned whether or not the city has the capacity to supply that amount of water. Mr. Galfour said if there is a fire the dewatering may have to be closed down, and because the water contains chlorine/fluoride he said he was not sure it would be permitted to be put back into the ground water. Using a worse-case scenario, he said dewatering might have to be terminated if an emergency situation arose. He said he was not absolutely sure whether the city could provide the water that might be needed, over the length of time it might be needed. The submission of a dewatering plan was requested. Transportation Division representative CLINT MORGAN testified regarding impacts and roadway improvements and hours of construction operation. He emphasized that improvements to Monster Road are required by code (Section 4-24-3). A traffic signal analysis has been requested for Grady Way and Longacres Drive. He said if it is determined a signal is needed, the city would not expect Metro to absorb the complete cost of the signal, but only provide their fair share. This would include impacts from construction traffic which is anticipated to continue until 1996. It was noted there will be limited construction during rush-hour traffic, with hauling limited from 8:30 AM to 3:30 PM. It was requested that Metro provide a Traffic Management Plan. He concluded saying the haul route on the private ownership portion of Longacres Drive (south of SW 16th) will have to be addressed for possible future use; a street cleaning bond should be in place; a roadway repair agreement should be a condition of approval; and said the Grady and Longacres intersection currently has a level of service of D and will go to an E level during this expansion. The applicant should determine what can be done to return this intersection to a D level of service. PENNY BRYANT representing the Police Denartment said the concern of her department is the haul routes, security procedures as to notification of the movement of chlorine or other hazardous chemicals, and access to storage buildings used for the chemicals. The Police and Fire Departments will work together to acknowledge notification of chemical movements. RANDY PARSONS from the Utility Systems Division said building and grading plans usually address the generation of storm water and any storm waters that may be polluted during the grading and filling operation and said a conceptual storm water plan should be provided prior to phase B. He also said he has not seen the plans for the fill and grade permit as yet. GERRI JACKSON from Metro said the Erosion Control Plan is now available for review. Randy Parsons said he will review the sizing and location of water quality management facilities. He said he has not as yet seen the conceptual storm water plan for the actual site approval. The Hearing Examiner questioned, because of certain plans that have not been submitted before this site plan review hearing, as to whether or not any staff member has determined if this is a complete application and ready for this site plan determination. RANDY PARSONS responded the plans are complete with respect to Phase A and recommended prior to issuance of any permits for phase B the utility plans be submitted to the Utility Systems Division for review and approval. The Hearing Examiner said the only reason he questioned the completeness of the application is because he wanted to have a complete set of plans for his, and staff's review. He noted site plan approval is generally for a two year period - the excavation is incorporated into it and it will take a substantial amount of time to prepare the site for the actual site plan that will be erected. This request for site plan approval, if for only two years, will not take this project up to the construction period. MS. JACKSON acknowledged the project is in three phases and Metro is asking that all three phases of the project be approved at this time. Further responding was Zoning Administrator DON ERICKSON. Erickson said the Site Plan Review Ordinance does allow for phased review. Regarding the Hold Harmless Agreement he said there is a chance the applicant may be making grading changes, and if that should occur the Hold Harmless Agreement would come into play because the city does not want to assume responsibility for final drainage plan design/revisions. The Examiner questioned if he had METRO WASTEWATER TREATMENT PLANT - Expansion III SA, SP-040-91 July 2, 1991 Page 5 the information required to review phase B at this time, and Erickson responded the Site Plan Ordinance allows for slight modifications in plans that can be reviewed and approved administratively. GERRI JACKSON from Metro responded the plan now is to run the storm water through the treatment plant, out the ETS, have no impacts to the existing system, no change to the site plan, and if after reviewing the new storm water manual if something is required that would require a change in the site plan then they would plan on coming back for review. The Examiner said his concern was two separate applications with two sets of requirements, - the grade and fill requiring detailed plans, and the site approval requires generalized plans. DAVE CHRISTIANSEN, Water Utility Division of the Public Works Department referenced Metro's comments regarding the study of the surcharge area and said the Waste Water Utility Section has no problem with their recommendation to remove the city collector sewers from the study - the city will be able to make its own determination. Regarding the May Valley Interceptor, the city and Metro have every intention of living up to the environmental and permitting processes that are required by law, and do not expect to circumvent those requirements. Ms. Jackson concluded stating if the Examiner was interested in having more information from the parties then let the record be kept open. The Hearing Examiner said the record would be held open to 5:00 P.M., June 14, 1991. PLANNER FORSANDER referenced Section 4 of the Memorandum of Agreement regarding mitigation measures, and said staff believes this is a complete application, subject to the conditions recommended by staff regarding submittal of additional documentation - and asked the Examiner's favorable review of the Site Plan and Special Permit requests. The Examiner announced due to the scope of this proposal he would be taking an additional week to issue his decision and conclusions. He called for further testimony. There was no one else wishing to speak, and no further comments from staff. The hearing closed at 12:30 P.M. FINDINGS, CONCLUSIONS & DECISION: Having reviewed the record in this matter, the Examiner now makes and enters the following: FINDINGS: 1. The applicant, The Municipality of Metropolitan Seattle (Metro), filed a request for approval of a Special Permit for Fill and Grade that would permit excavation, grading and backfilling on a portion of the Renton Wastewater Treatment Plant, together with a request for approval of a Site Plan for an expansion of the plant. 2. The yellow file containing the staff report, the State Environmental Policy Act (SEPA) documentation and other pertinent materials was entered into the record as Exhibit ul. 3. The applicant took lead agency responsibility for the proposed expansion and prepared an EIS for the proposal. The document was prepared as a Supplemental EIS which supplemented the environmental analysis prepared for the 1981 and 1986 plant expansions. 4. The subject proposal was reviewed by all departments with an interest in the matter. 5. The subject site is located at 1200 Monster Road which is the site of the Metro Renton Sewer Treatment Plant. The site is bounded on the west by Monster Road, on the north and east by Oakesdale Avenue and the P-1 Channel, and on the south by Longacres Drive and I-405. 6. The site is approximately 84.5 acres in area. The site is roughly shaped like a pentagon. The fifth angle is aimed just west of north. 7. The generally level site is surrounded by substantial areas of berming that serve to contain any accidental spill, and to screen the surrounding areas from the treatment plant. The water tower marks the prominent high point of the site and is located along the western edge of the complex. It is located about a third of the way south from the northernmost area of the site. The level central area of the site is at an elevation of just over 100 feet. The site slopes upward along the northern half of the west boundary of the site, with the water tower's base located at just under 200 feet. 8. The site was annexed to the city with the adoption of Ordinance 1745 as amended by Ordinances 1764 and 1928, enacted in April, 1959, May, 1959 and December, 1961, respectively. 9. A number of land use permits have been issued by the city for various aspects of the plant including prior expansions and upgrades for equipment. Those various approvals have permitted the development that now exists on the site. i METRO WASTEWATER TREATMENT PLANT - Expansion III SA, SP-040-91 July 2, 1991 Page 6 10. Springbrook Creek is generally located within 80 feet of the east boundary of the site. The distance varies somewhat as the creek and the site's boundary both meander. The intervening property is owned by the Soil Conservation Service. Since the site is located within 200 feet of Springbrook Creek (also called the P-1 channel) development of the site is also governed by the City of Renton's Shoreline Management Program. The applicant has applied for the appropriate Substantial Development Permit. That permit is not specifically reviewed in this decision since approval of a Substantial Development Permit does not lie with the Hearing Examiner. 11. The existing treatment plant has been located in this vicinity for approximately 25 years, although it has undergone a number of expansions and modifications over those 25 years. The plant treats raw sewage and separates treated residual solid wastes from treated water. The solids, generally known as sludge, are eventually trucked off-site for disposal or reuse, as appropriate. The treated water, also known as effluent, is discharged by underground pipe, known as the Effluent Transfer System (ETS) to Elliot Bay. The effluent at one time was discharged into the Green/Duwamish River system just west of the plant. Some storm water is still discharged through the old pipe system to the Green River. The older discharge pipe to the Green River is still maintained. The potential for excess flows to be discharged via this pipeline to the Green River still exists under special permit authority from state and federal agencies. 12. The plant sits at the eastern edge of a node of industrial uses congregated around Monster Road. East and north of the plant the uses, or at least proposed uses, tend to be office park uses, composed primarily of low-rise office buildings. Light industrial uses pick up again east of Powell Avenue S.W. South of the plant is I-405 and the Longacres/Boeing property. Proposed uses after the phasing out of horse racing are additional office park facilities. 13. The plant now has the capacity to process approximately 72 million gallons of raw sewage. The proposed expansion will increase processing capacity to approximately 108 million gallons per day (mgd). Potential additional expansions could further increase capacity to the ultimate design capacity of approximately 250 mgd. 14. The treatment of sewage can be described in terms of two processes. There is the liquid stream process and the solid stream process. The liquid stream process begins with the entry of waste water gathered from the various sewer lines entering the plants headworks. At that point debris and grit are filtered from the waste water. Approximately 60 percent of the solids are removed during primary treatment which is a sedimentation process where solids settle out of the waste water and additional materials float and are skimmed. The waste water than enters a secondary treatment process. Secondary treatment employs microorganisms and oxygen to breakdown the organic constituents of the waste water. The waste water then enters the secondary sedimentation tanks. The solids resulting from secondary treatment, microbes and other solids, settle out of the waste water. At this point the waste water (effluent) is separated from the solids. The effluent is treated with chlorine in chlorine contact channels and eventually released through the pipeline to Puget Sound. 15. The second process prepares the solids for disposal. The very liquid sludge, about I percent solids and 99 percent water, is passed through the dissolved air floatation thickeners (DAFT). In this process, air bubbles attach to the small solid particles. This solids-air mixture floats to the surface where it may be skimmed. Digesters again employ a biological breakdown process, an anaerobic process (in the absence of air) to further breakdown the solids and reduce the majority of pathogens (disease producing bacteria). Not all pathogens are killed by the treatment process and currently some remain in the sludge. Some pathogens also remain in the waste water. The sludge is then dewatered to further thicken it by using chemical thickeners and filters. The sludge is then trucked off-site for disposal. 16. The main components of the treatment plant are located around the perimeter of the site, concentrated primarily in the south, west and north. At the extreme southeast corner of the complex is the chlorine containment building where up to two (2) rail cars containing chlorine can be stored simultaneously (See below). The secondary sedimentation tanks, sixteen in number, (two (2) tiers of eight (8) each, are located just north of the south property line, north of the rail line that serves the chlorine building. In the southwest corner of the complex is the effluent pumping station. North of this pumping station and just west of the secondary sedimentation tanks are the maintenance buildings. 17. The Administration Building is located at the westernmost angle of the pentagon-shaped site, where Monster Road turns sharply south. A number of support facilities are clustered in this area. East of the Administration Building are the primary sedimentation tanks followed by the rectangular-shaped aeration basins. METRO WASTEWATER TREATMENT PLANT - Expansion III SA, SP-040-91 July 2, 1991 Page 7 18. The water tower is along the western perimeter of the site as previously described. At the northern most angle of the pentagon-shaped site are some wetland areas that remain undeveloped. To the south and east of these wetland areas are the solids/semisolids handling facilities. Immediately south of the wetlands are the anaerobic digesters. South of the digesters, clustered on the west are the dissolved air floatation thickeners. East of the thickeners is the sludge blending and storage tank. The sludge dewatering facility and the truck loading area are immediately east of the blending areas near the 7th Avenue bridge entrance to the complex at Oakesdale. 19. The applicant will be adding additional treatment facilities that expand the plant's ability to treat raw sewage. In addition to the new facilities, some of the existing facilities will be modified to either increase capacity or improve aspects of the process to better control odors. The applicant will also modify aspects of the plan to meet new earthquake criteria. The applicant will add a pod of four additional secondary sedimentation tanks immediately north of the easternmost pod of existing tanks. Additional aeration basins will be added on the east side of the existing basins. Grit handling will be added west of the existing aeration basins. Four primary sedimentation tanks will be added north of the existing tanks. The roof system will be strengthened to comply with current seismic codes (Page 7, 4th full paragraph, Metro's Project Narrative, May 20, 1991). The anaerobic digesters will be modified to increase capacity and better contain odors. The lids will be refitted to contain odors. Two new dissolved air floatation thickeners will be added just west of the existing 4 thickeners. Odor scrubbers will be added to the aeration basins and primary sedimentation processes, and an odor reduction tower will be added to the solids handling process area. A new waste gas burner will be added to burn off excess methane, a byproduct of sewage treatment. 20. Many of the processes occur in facilities that are constructed at or below ground level. Many of the new facilities will follow this formula, thereby requiring a substantial amount of site preparation and excavation, prior to actual facilities construction. 21. The applicant proposes dividing or phasing the work over approximately 5 to 6 years. The first phase, Phase A, would involve a variety of site preparation stages including removing vegetation, excavating the future facilities areas, dewatering soils, filling and constructing earthen perimeter berms and landscaping the perimeter of the site. The applicant has indicated that this work will take approximately 2 years, from 1991 to 1993. 22. Phase B, the second phase, would run from approximately 1993 to 1996. This phase would involve the actual construction work of building new facilities and modifying some of the existing facilities. 23. The final phase, Phase C, would involve cleanup work and the interior landscaping of unused portions of the site. 24. In order to excavate the site and construct the berms the applicant has applied for a Special Permit to fill and grade the site under the Mining, Excavation and Grading Ordinance. The applicant will excavate approximately 260,000 cubic yards of material to accommodate most of the below grade structures. If the soils are suitable for reuse, approximately 100,000 cubic yards of these soils will be used to construct and modify the perimeter berm. The remaining soils will be used to backfill around the tanks and other structures. 25. If the materials are found unsuitable for reuse, they will be exported from the site and disposed of as appropriate for the level of contamination. In addition, if these materials are inappropriate for reuse soils will have to be imported for the berming and backfilling. 26. In addition, top soil to support new landscaping and construction grade backfill will be imported to the site. These materials total approximately 80,000 cubic yards: 45,000 for landscaping and 35,000 for backfill. Approximately 160,000 square feet of pavement and 7,700 feet of curb and gutter will also be removed from the site and suitably disposed of. 27. The number of one-way truck trips to support these activities (assuming the native excavated materials can be reused) will be approximately 200 to 300 per day. During the construction phase there will be approximately 425 to 475 trips per day, including construction worker trips in addition to the large construction delivery vehicles. In order to accommodate the normal peak or rush hour traffic, and to avoid conflicts with commuters, truck flow to the site will be restricted to the hours between 8:30 AM and 3:30 PM. 28. The applicant has not completed its Transportation Management Plan (TMP) at this time but one is required by the city. t METRO WASTEWATER TREATMENT PLANT - Expansion III SA, SP-040-91 July 2, 1991 Page 8 29. Due to the low elevation of the site and the high water table, site preparation will also require that the site be dewatered to keep the excavation holes dry and suitable for the new additions. In addition, water will be extracted from the excavated soils. In order to minimize settling of the existing plant facilities the hydrology surrounding those facilities would need to be maintained. In order to facilitate this, the water extracted during dewatering of the excavated areas would be reintroduced into the surrounding soils. 30. Mirroring the potential for contaminated soils, a possibility exists that the extracted water could also be contaminated. If the water is too contaminated it would be treated and added to the plant's sewage effluent. In this case water to maintain the site's sensitive hydrology would have to be replaced. The water could be drawn from city sources, although the city is concerned that sufficient quantities, up to 5,000 gallons per minute, would over-tax the city's capacity. Subsequent to the public hearing the applicant indicted some other potential sources for this water including additional wells and possibly the Green River. 31. There will be only minor changes to the internal roadway system serving the various locations within the plant. The five entrances will be reduced to four entrances with the main entrance and public access limited to the Monster Road access. The sludge handling area, which encounters the largest number of truck movements during normal operation, (as opposed to construction activity) will be modified to permit easier turning of trucks, and grades will be altered to provide less impediments during icy conditions. The applicant will be adding an additional 35 parking stalls. 32. The two small wetlands located near the north end of the site will be maintained and enhanced. While analysis indicates that they have suffered from past practices, staff and Metro have determined that they do serve as wildlife habitat and probably help recharge the hydrology of the site and surrounding areas. They will be buffered, and during construction they will be protected from sedimentation and run-off from construction related activities. 33. Metro uses chlorine in the process to deodorize the sewage and to kill pathogens. As indicated earlier, the chlorine storage building is located near the southeast corner of the complex. The facilities can contain two separate railroad tank cars at one time. Each tank car has a 90 ton capacity. Under current operating conditions the facility generally houses approximately 100 tons of chlorine at any one time. When a tank car is down to approximately 10 tons of chlorine the plant orders a new tank car of 90 tons. This results in the maximum storage of approximately 100 tons of chlorine at any one time. 34. At current capacity the plant receives a new chlorine shipment approximately every six to twelve weeks. The expanded plant would double the use and result in more frequent shipments of chlorine to the site. Emergency personnel are concerned about chlorine shipments through the city, and particularly in this area where large numbers of people are employed, and at least currently congregate at Longacres Racetrack. 35. Questions about shipping of chlorine, storage of the chlorine and emergency procedures were raised by both the Fire Department and the Police Department. Metro claims it has no control of the shipment or potential storage of chlorine on rail lines or sidings within the city, and receives minimum advanced notice of its arrival. The city wants more effective communications in this area. 36. In addition to the storage of chlorine at the facility, other hazardous or toxic materials are used or stored routinely at the complex including sulfur dioxide and sodium hydroxide. Methane gas, a byproduct of the solids processing, is produced on-site and is funnelled off and sold to Washington Natural Gas. Other substances are also produced by waste water processing including hydrogen sulfide, a poisonous gas which emits the characteristic rotten egg odor. The Fire Department requested all storage and use be subject to the current standards of Article 80 of the Uniform Fire Code. 37. The applicant proposes supplementing the existing landscaping and creating a berm around the perimeter of the site. Existing landscaping efforts which go back a number of years have succeeded in accomplishing very little screening of the plant. The existing slow growing or undersized specimens have provided very little effective visual buffering of the plant. 38. Staff has recommended that the applicant bolster the proposed landscaping along the eastern boundary from the south property line to the bridge over Springbrook Creek. 39. A heron rookery is located approximately 1,500 feet north of the treatment plant. Staff analysis reveals that past construction activity at the plant has not demonstrably affected the rookery, although the science of rookery analysis is still imprecise. f METRO WASTEWATER TREATMENT PLANT - Expansion III SA, SP-040-91 July 2, 1991 Page 9 40. The plant's noisy equipment is generally confined to buildings. Acoustical treatment is proposed to control operational noise. Construction equipment and the construction process will generate some additional noise. 41. The applicant has proposed an odor control standard that is intended to reduce the odor at the plant's boundaries to minimal levels. The standard would reduce the odor at the boundary to five (5) odor units, a standard that measures detectable levels (as determined by a panel of citizens) and dilutes that odor with a mix of normal air to approach a threshold level. 42. The applicant will be required to improve to city standards roads abutting the plant including Monster Road, and those portions of Longacres Drive that are public right-of-way. There is some confusion about the public/private status of certain portions of Longacres Drive. 43. Storm water management, both during construction and during routine operation, will have to meet city standards. Preliminary plans submitted by the applicant for the operation appear to satisfy staff requirements. The control plans for the grade and fill appear to be less than normally required. The plans will have to be certified, in writing, by staff, that they are complete, prior to the expiration of the appeal period. 44. A 30 foot setback will be provided adjacent to Oakesdale Ave. A 25 foot setback will be provided along Monster Road. 45. The Staff Report listed a number of conditions on any approval. Those conditions are attached hereto as are the applicant's response to those conditions and the city's further response. CONCLUSIONS Grade and Fill 1. These conclusions begin with the Grade and Fill Permit since both excavation and grading are required as a prelude to the actual development of the site plan. 2. The Mining, Grading and Excavation ordinance provides a number of specific criteria for reviewing a site plan. Those criteria are generally represented in part by the following enumeration: a. size and location of the activity; b. traffic volumes and patterns; C. screening, landscaping, fencing and setbacks; d. unsightliness, noise and dust; and e. surface drainage. The proposed excavation and regrading of the site appears to generally conform with these criteria. This office was most interested in the applicant's compliance with the application requirements. Subsequent to the public hearing the applicant supplemented the record in areas of drainage and erosion control. While the information should have been submitted earlier, staff has responded that the applicant has complied with the major requirements and that sufficient. detail has been provided to permit staff review and eventual approval. 3. The large volume of materials excavated from the site, approximately 260,000 cubic yards, will be reused to construct the berm and backfill around the major structures. Reuse will depend upon whether the materials are contaminated. Materials not immediately reused will be stockpiled. This on-site reuse should substantially reduce the amount of traffic generated by the operation, sparing the roads and surrounding uses, traffic, dust and debris. 4. One of the main issues is the dewatering of the site to allow the applicant to construct facilities that will be located for the most part below the water table. The proposed system will dewater the excavated areas while recharging the areas adjacent to existing structures to prevent subsidence. Subsidence would occur as ground water is withdrawn. The extracted water will, like the soils, be reused if it is not contaminated. Excess water can be disposed of in a number of ways, including introduction into the sewage flow or drainage into the adjacent Green River if water quality concerns can be satisfied. If the water is contaminated it will be appropriately treated and discharged into the effluent transfer system. If the water cannot be reused for recharge then other water will have to be introduced to the site. The applicant's plans now include a number of contingencies including withdrawing water from the Green River, digging f METRO WASTEWATER TREATMENT PLANT - Expansion III SA, SP-040-91 July 2, 1991 Page 10 additional clean water wells which will not create subsidence, and utilizing city water. The last contingency could create problems for the city utility, although the applicant has also modified the total draw from approximately 5,000 gallons per minute to substantially reduced rates. Any use of city water will have to be strictly analyzed. 5. As discussed above, the city requires a Transportation Management Plan for the construction vehicles. The city believes that with limitations that avoid conflicts with the commuting hours, traffic for the project should not create any undue impacts on the traffic flow. The large number of trips and the type of trips (very heavy trucks) can be expected to damage the road surface. The city expects to be reimbursed for road damage attributable to Metro's construction activity. Similarly, the city expects the roads to be kept clear of debris, and requested that the applicant post a bond that would be used for street cleaning if the applicant fails to accomplish this objective. 6. The applicant plans to develop the landscaping and screening early in the process and this is a welcomed move. The current screening and landscaping have not effectively buffered surrounding properties from the plant. Since the areas east and north of the site are intended to provide opportunities for high quality office park uses, the better screening and landscaping will assist in isolating the plant and making these adjacent properties more inviting for office workers. In order to effectuate the Comprehensive Plan's objectives for this area the applicant should use larger specimens along the north and eastern edge of the site, and supplement the proposed plantings along those same margins, subject to approval by the planning staff. 7. The applicant will be maintaining setbacks as required by code, with 30 feet along Oakesdale Ave and 25 feet along Monster Road. 8. The applicant will be guided by city requirements in limiting fugitive dust. The city has also imposed limitations on the hours the applicant can operate to limit after hours noise. As with any construction site, there will be some unavoidable noise. 9. The applicant has proposed protecting the on-site wetlands and Springbrook Creek with appropriate erosion control measures including silt fences and construction fences to limit entry. Runoff collected on the site will be treated, if necessary, and released into the effluent transfer system - and if treatment is not necessary may be released to the Green River. Storm water management and disposal is subject to modified federal regulations. The applicant will have to comply with any NPDES permit. All city requirements for surface water and storm water management will be observed by the applicant. Site Plan 10. The Site Plan Ordinance provides a number of specific criteria for reviewing a site plan. Those criteria are generally represented in part by the following enumeration: a. Conformance with the Comprehensive Plan; b. Conformance with the Building and Zoning Codes; C. Mitigation of impacts on surrounding properties and uses; d. Mitigation of the impacts of the proposal on the subject site itself; e. Conservation of property values; f. Provision for safe and efficient vehicle and pedestrian circulation; g. Provision of adequate light and air; h. Adequacy of public services to accommodate the proposed use; The proposed use satisfies these and other particulars of the ordinance. 11. The existing treatment plant and proposed expansion are compatible with the Comprehensive Plan's designation of the site as suitable for public and quasi-public uses. Obviously the treatment of urban sewage supports the other residential, commercial and industrial uses located in the treatment plant's service area that includes wide areas of the east side outside the city limits. f METRO WASTEWATER TREATMENT PLANT - Expansion III SA, SP-040-91 July 2, 1991 Page 11 12. The proposal is compatible with the city's Zoning Code. The site, zoned P-1, is designated for public uses such as that proposed. The plant meets or exceeds the setback requirements of the zone and complies with the height limitations. Specific plans have not been reviewed for compliance with the building codes but that will occur as plans progress. Building code compliance is not required during site plan review. There appear to be some questions about the plant's compliance with portions of the Uniform Fire Code, specifically Article 80 regarding the storage and dispensing of existing and proposed hazardous materials. The Fire Department required that: "All hazardous materials operation at the Metro Wastewater Treatment Plant must meet minimums specified in Article 80 UFC." This issue will be further reviewed below. 13. The plant is set off from surrounding uses by roads along most property lines and by a combination of road and waterway along the eastern property line. The proposed berm is also intended to further separate the plant from surrounding uses. Supplementing the physical isolation provided by the roads, Springbrook Creek and the berms will be the perimeter landscaping. The generally low-rise nature of many of the plants facilities will also minimize the spillover of unaesthetic aspects of the plant. This is not to minimize the fact that this site has always looked like some kind of industrial treatment plant. 14. As a practical matter the plant probably goes as far as it can in minimizing the impacts of this development on the site itself. The applicant proposes preserving the two wetland areas and buffering them from the plant, and more importantly plant construction. The berm and perimeter landscaping provide positive aspects to the proposal. The one area that is weak is the proposed perimeter trail system. The site's environmentally interesting locale, adjacent to Springbrook Creek and south of the Heron rookery should be utilized more effectively for public use. Placing the trail within the cyclone fencing substantially detracts from its usefulness. The trail should be relocated to the outside of the plant fence. This would enable it to be part of the developing trail system in this area of the Valley. While the applicant proposes interior landscaping, that may be only an interim measure and really cannot be a permanent selling point in appraising the project. The applicant and staff suggested that the plant will blend in and provide the campus-type environment found in the surrounding office park uses, and the campus-type development generally encouraged in this area. One should not attempt to force the office park analogy too far. The site is most definitely used for a sewer treatment plant, and unless the new plantings can succeed better than the current landscaping installation, it will still look like a plant and not an office park. In addition, too much stress or reliance has been directed at the interior landscaping. While this interior landscaping may remain long-term, it is strictly intended to be temporary. Only smaller species and grasses and the like will be planted. Just when it gets well-established (in about 10 years) it may yield to further expansion of the plant. 15. The further expansion of the plant should not have a substantial impact on property values. Frankly, this is a utilitarian use, and one necessary for the development of other commercial or residential uses. The new landscaping and upgrading of the odor control equipment should make the plant a more compatible neighbor and that is all that can be hoped for, 16. The interior circulation patterns appear safe and efficient. The absence of a clearly defined Transportation Management Plan for the construction related traffic makes it difficult to determine that off-site impacts will be acceptable. The limitation on hauling during peak hours will assist in minimizing conflicts between the hauling/construction trucks and commuters. The applicant will have to submit a Transportation Management Plan that is acceptable to the city. In addition, the applicant will have to demonstrate a working arrangement to use Longacres Drive. 17. The generally low-rise nature of most of the structures at the complex should permit adequate entry of light and air to the interior spaces of the plant. Many of the structures are just at or below grade, and those that are above grade are usually one story or narrow stack-type structures. The plant's containment systems of the odor producing processes have been redesigned to reduce and minimize objectionable odors beyond the plant's boundaries. Metro has indicated that it will respond quickly to complaints about odors. 18. The plants processes are not particularly noisy and the installation of additional landscaping and noise attenuating systems should reduce this further. Construction related noises are not easily avoided but the limitation on the hours of operation should minimize the impact on any residential uses located north of the site. 19. In the area of public services there two main concerns. The Fire and Police Departments are concerned about the shipment and storage of chlorine, and the storage of other hazardous and toxic chemicals. The Water Utility Division has expressed concern about its ability to provide water to re-hydrate the site if the ground water extracted from the site is too contaminated to be reused. Staff has agreed that the Fire and Police Departments can work together to METRO WASTEWATER TREATMENT PLANT - Expansion III SA, SP-040-91 July 2, 1991 Page 12 coordinate information, and that separate notices to each department are unnecessary. The applicant should provide the information it can about the ordering and delivery of chlorine and other toxic or hazardous materials. 20. The Fire Department's request for compliance with Article 80 of the Uniform Fire Code is reasonable and shall be complied with by the applicant. In addition, the applicant shall be required to comply in all matters dealing with the storage and use of hazardous and toxic materials with the current requirements of Article 80. The applicant intends to comply with current earthquake standards in remodeling certain parts of the complex, and compliance with safety standards should be no different. In areas of where the public health, safety and welfare is definitely an issue a requirement for compliance with current standards for such a major upgrade and expansion of this facility are not unwarranted or unreasonable. In Metro's case we are dealing with the storage and handling of major quantities of hazardous and toxic chemicals in an area where large numbers of people work or gather. We are not dealing with mere aesthetic considerations. The issues clearly involve life safety, and caution is completely warranted. 21. In conclusion, the applicant is making major changes to the Renton Sewage Treatment Plant which requires work within 200 feet of Springbrook Creek, within 1,500 feet of a sensitive heron rookery, subjects the citizens of Renton communities to the extra transport of hazardous materials including Chlorine, Sulfur Dioxide and Sodium Hydroxide, and which is located within a few hundred yards of land designated for high caliber office park development. In addition, nearly 85 acres of land has been removed from the tax rolls that might have served, shall we say, more congenial uses. Finally, major sewer trunk lines run through large areas of the city including through aquifer recharge areas that have the potential for great harm. Obviously there have been tradeoffs. The loss of taxable land has served an important public purpose, but at a greater expense to residents of the city than the overall community the plant serves. Under those circumstances, and accepting Metro's own analysis of Compliance (Metro Letter, June 3, 1991, Page 1, Last Full Paragraph) which references terms found in the Memorandum of Agreement, it seems both reasonable and appropriate to impose independently the mitigation measures outlined in the MOA to assure that the project would be in full compliance and remain compatible with city codes, goals and policies. Therefore, those measures outlined in the MOA that provide mitigation shall be required as a condition of approval of both the special permit and the site plan. Any expansion of the plant will have the impacts enumerated by staff even if the August deadline passes. Therefore, the mitigation measures contained in the MOA shall be required for any currently proposed plant expansion. 22. This report would not be complete without some observations on the awkward issues raised by the Memorandum of Agreement. While it would be easy to commend Metro on its attempt to minimize costs to the public, it has shown less than a commendable attitude toward the public hearing process. The Memorandum of Agreement stresses deadlines over public participation. City staff was placed in the untenable position of having to weigh a potential petitioner's fair right to appeal or raise legitimate issues at the public hearing against the potential loss of about $11,000,000 worth of mitigation measures. Sections 3.2.6, 3.2.7. and 3.2.8 all appear to foreclose public input that might require further review by the city's professional staff. These limitations appear to have proscribed the public's ability to question either the Metro staff or city staff since any questions that might delay resolution in Metro's favor could jeopardize the city's receipt of the mitigation funds. Section 3.2.5 appears to foreclose the Examiner's ability to have staff fairly evaluate potential mitigations measures that seem appropriate based upon any testimony or evidence submitted at the public hearing. The Examiner relies on receiving these unfettered recommendations based on evidence adduced at a public hearing. This office will readily admit that the public hearing process is not the most expeditious method for reviewing projects, whether public or private. That is not the issue. What is probably most ironic is that staff probably would have recommended the proposal in any event, although the process may have taken a bit longer. Instead, agreements such as the MOA adversely reflect on the credibility of this office and tarnish the credentials of professional staff. The hearing system is placed in harm's way by agreements like the Memorandum of Agreement. It unnecessarily raises questions about the objectivity of staff in reviewing this application. While the end result, at least from this office's perspective, was probably not compromised, appearances in judicial and quasi-judicial forums are as important, if not more important. The public's perceptions of a public hearing creates the frame of reference for whether they believe i METRO WASTEWATER TREATMENT PLANT - Expansion III SA, SP-040-91 July 2, 1991 Page 13 the decision was impartially arrived at by the decision-makers. The Memorandum of Agreement jeopardizes those perceptions. That was unfortunate. DECISION Both the Special Permit to excavate, grade and fill the site and the Site Plan are approved for three (3) phases, subject to the following conditions: 1. Wetland Mitigation/Compensation. Because of potential impacts to existing on-site wetlands, and because the proposed use is not water-dependent, as required by the City's Shoreline Master Program, the applicant shall commit to fund up to $3,500,000 for the acquisition of riparian wetland and uplands that could serve as habitat for wildlife within 2500 feet of the plant boundary. These wetland/wildlife improvements shall be permanently dedicated to the public for the purposes of wildlife preservation and enhancement, including use by the city for interpretive trail purposes. 2. Environmental Health/Public Safety Mitigation/Compensation. Because of potential impacts of the project identified in the EIS in the areas of Environmental Health and Public Safety, the applicant shall commit to fund $2,500,000 for public safety and community improvements within the City of Renton to enhance fire and emergency response to the Wastewater Treatment Plant. 3. Conveyance System Impacts Mitigation. Because of potential impacts on the City of Renton's Sole Source Aquifer and other environmentally sensitive areas from the Wastewater Treatment Plant's sewage conveyance system, the applicant shall commit to design and construct several off-site sewage system improvement projects and associated local sewerage facility improvements related to the proposal. These shall include: the Cedar River Trunk Relocation; the May Valley Interceptor Extension; and the Cascade Siphon/Footbridge. These projects will be subject to separate permitting and environmental review processes. Other system improvement projects may be added by mutually written agreement of the City and Metro. The estimated total cost of the system improvement projects is $4,755,000 which will be borne solely by Metro. The City of Renton has agreed to reimburse Metro for design and construction costs associated with any local sewerage facility improvements, after project completion in 1996. 4. Additional Studies Required. Prior to the issuance of any permits for Phase B construction the applicant shall submit and obtain city staff review of the following studies: a. Generalized Utilities Plans. These shall consist of preliminary plan drawings and calculations for the following utilities: 1. Storm and Surface Water Drainage. This shall identify the location and preliminary size of storm and surface water control facilities needed to meet all of the applicable Core and Special Requirements contained in Chapter 1 of the King County Surface Water Design Manual, which the City of Renton has adopted. Storm and surface water facilities should be preliminarily sized and shown schematically on the site plan. The plan must address methods for meeting water quality requirements for the impervious areas subject to storage of chemicals or vehicular use, prior to direct discharge to the Green River or ETS. 2. Sewer. This shall consist of a report containing engineering calculations that demonstrates the City of Renton Wastewater Utility Department's requirement that surcharging of the interceptors around the Metro Wastewater Treatment Plant will not exceed two feet below the rim of any manhole (approximate elevation 13) within the Metro system. 3. Water. This shall identify fire flow requirements (see Item No. 2 below) and water main extensions and improvements such as hydrants, fire sprinkler systems, backflow preventers etc. Proposed improvements shall be shown schematically on the site plan. Plans shall show proposed improvements and utility relocations separately. b. Fire and Emergency Management Plans/Special Operations Plan for Storage and Handling of Hazardous Materials. These plans shall address the following: METRO WASTEWATER TREATMENT PLANT - Expansion III SA, SP-040-91 July 2, 1991 Page 14 1. Access. Primary and secondary access routes are to be maintained with prior approval of the City of Renton Fire Prevention Bureau Chief. Once established, these emergency access routes cannot be changed without Fire Prevention approval. 2. Water. The applicant must coordinate all interruption of water supply serving hydrants and sprinkler systems with Fire Prevention. 3. Fire Flow. The applicant shall provide sufficient information regarding building and facility construction to include: type of construction, total area in square feet, type of use including hazardous use of each building or facility. This analysis shall address the specific requirements regarding fire hydrants, fire suppression and alarm systems. 4. Article 80 of the Uniform Fire Code. The applicant shall address compliance with Article 80 of the Uniform Fire Code regarding all storage and dispensing of existing and proposed hazardous materials. All hazardous materials operations at the Metro Wastewater Treatment Plant shall be required to comply in all matters dealing with the storage and use of hazardous and toxic materials with the current requirements of Article 80. C. Landscaping Plans. The applicant shall submit detailed landscaping development plans for the following: 1. Detailed Landscape Plan for Phase C Internal Planting. This plan shall address proposed grading, plant materials and layout, and irrigation for the interior facility landscaping to be developed in Phase C. 2. Detailed Landscape Plan for Additional Perimeter Landscaping in Phase C. This plan shall address the area along the site perimeter not included in the Phase A planting plan. This is the area along the Springbrook Creek between SW 7th Street and SW Grady Way. This plan shall include proposed grading, plant materials/layout and irrigation. Implementation of this plan should occur in Phase C, or as soon as possible after adjacent facilities (Chlorine Contact Channel extension) are completed. The trail shall be relocated to the outside of the plant fence. 3. The trail shall be relocated to the outside of the plant fence. 4. Subject to staff approval landscape specimens shall be as large as possible for all landscape plans. d. The applicant shall have to demonstrate a working arrangement to use Longacres Drive. e. The applicant shall have to submit a Transportation Management Plan that is acceptable to the city. f. Metro shall repair or pay the city for the repair of any damage to roadways or infrastructure that can reasonably be attributed to Metro's construction activities, prior to the issuance of the final occupancy permit. Any such damage shall be repaired to the conditions that existed prior to the initiation of Metro's construction activities. g. The applicant shall post a bond in an amount to be determined by Public Works that shall be used to clean roads of debris if the applicant fails to do so. h. The applicant shall be required to comply with all code requirements for street improvements adjacent to the subject site. I. The applicant shall comply with city policy regarding LOS of Service and traffic signal warrant analysis. j. Grady Way TBZ. The applicant shall participate in the Grady Way Transportation Benefit Zone pursuant to City Resolution No. 2827. This is estimated to be $44,091 [213 increased vehicle trips x $207/trip], and should be paid at the time the building permit is issued. METRO WASTEWATER TREATMENT PLANT - Expansion III SA, SP-040-91 July 2, 1991 Page 15 k. Roadway and Infrastructure Repair. Metro shall repair or pay the City of Renton for the repair of any damage to roadways or infrastructure resulting from construction, prior to the issuance of the final occupancy permit. 1. Detailed Erosion Control Plan. Prior to issuance of the first permit for the project (Grading License), the applicant shall submit an Erosion Control Plan for City staff review. This plan must also be included in the applicant's construction contract for Phase A, Site Preparation. The plans will have to be certified in writing by staff as complete prior to the expiration of the appeal period M. 2020 Plus Planning Participation. The applicant shall ensure City of Renton participation in all technical reviews of the Metro Wastewater 2020 Plus Study. Participation shall include the City of Renton Public Works Director and representatives from the Wastewater Utility Section, Long-Range Planning, Current Planning and the Mayor's Office. n. Security Procedures. Security procedures should be established, in coordination with the City of Renton Police Department, for protection of the wastewater treatment plant, and particularly the outside storage of liquid chlorine and other hazardous materials. The applicant shall contact the Fire Department as soon as practical in advance of any chlorine tank car movements, both inside and outside the wastewater treatment plant. ORDERED THIS 2nd day of July, 1991. FRED J. KA MAN HEARING EXAMINER TRANSMITTED THIS 2nd day of July, 1991 to the parties of record: Gerri Jackson METRO 821 Second Avenue Seattle, WA 98104 MAIL STOP 122 Jack Warburton Brown and Caldwell Engineers 1232 East Crockett Seattle, WA 98102 Vicky Renier METRO 821 Second Avenue Seattle, WA 98104 MAIL STOP 130 William Horne 14703 S.E. 100th street Renton, WA 98059 Perry Weinberg Preston Thorgrimson Shidler Gates & Ellis Attorneys at Law 5400 Columbia Center, 701 Fifth Avenue Seattle, WA 98104-7078 TRANSMITTED THIS 2nd day of July, 1991 to the following: Mayor Earl Clymer Councilman Richard M. Stredicke Don Erickson, Zoning Administrator Lynn A. Guttmann, Administrator Members, Renton Planning Commission Jim Hanson, Development Services Manager Gary Gotti, Fire Marshal Ronald Nelson, Building Director Lawrence J. Warren, City Attorney Jay Covington, Mayor's Executive Assistant Transportation Systems Division Valley Daily News Utilities System Division f METRO WASTEWATER TREATMENT PLANT - Expansion III SA, SP-040-91 July 2, 1991 Page 16 Pursuant to Title IV, Chapter 8, Section 15 of the City's Code, request for reconsideration must be filed in writing on or before 5:00 P.M. July 16, 1991. Any aggrieved person feeling that the decision of the Examiner is ambiguous or based on erroneous procedure, errors of law or fact, error in judgment, or the discovery of new evidence which could not be reasonably available at the prior hearing may make a written request for a review by the Examiner within fourteen (14) days from the date of the Examiner's decision. This request shall set forth the specific ambiguities or errors discovered by such appellant, and the Examiner may, after review of the record, take further action as he deems proper. An appeal to the City Council is governed by Title IV, Chapter 8, Section 16, which requires that such appeal be filed with the City Clerk, accompanying a filing fee of $75.00 and meeting other specified requirements. Copies of this ordinance are available for inspection or purchase in the Finance Department, first floor of City Hall. The Appearance of Fairness Doctrine provides that no ex parte (private one-on-one) communications may occur concerning pending land use decisions. This means that parties to a land use decision may not communicate in private with any decision-maker concerning the proposal. Decision-makers in the land use process include both the Hearing Examiner and members of the City Council. All communications concerning the proposal must be made in public. This public communication permits all interested parties to know the contents of the communication and would allow them to openly rebut the evidence. Any violation of this doctrine would result in the invalidation of the request by the Court. The Doctrine applies not only to the initial public hearing but to all Requests for Reconsideration as well as Appeals to the City Council. f PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 12 H. DEPARTMENTAL RECOMMENDATION: Staff recommend that the Hearing Examiner determine In favor of the proposed Site Plan Approval, Shoreline Substantial Development Permit, Special Permit for Grading for Metro's Wastewater Treatment Plant, Expansion III (File No. SA;SM;SP-040-91), subject to the following conditions: 1. Site Plan Approval: a) Mitigation Measures: Because of the Impacts Identified In the FEIS for the project, the applicant shall agree to implement all Mitigation measures, as specified In Exhibit B of the attached Memorandum of Agreement [Attachment No. 4], and shall agree to implement the MOA according to its terms and conditions including the following: (1) Wetland Mitigation/Compensation. Because of potential Impacts to existing on-site wetlands, and because the proposed use is not water- dependent, as required by the City's Shoreline Master Program, the applicant shall commit to fund up to $3,500,000 for the acquisition of riparian wetland and uplands that could serve as habitat for wildlife within 2500 feet of the plant boundary. These wetland/wildlife improvements shall be permanently dedicated to the public for the purposes of wildlife preservation and enhancement, including use by the City for interpretive trail purposes. (2) Environmental Health/Public Safety Mitigation/Compensation. Because of potential Impacts of the project identified in the EIS in the areas of Environmental Health and Public Safety, the applicant shall commit to fund $2,500,000 for public safety and community improvements within the City of Renton to enhance fire and emergency response to the Wastewater Treatment Plant. (3) Conveyance System Impacts Mitigation. Because of potential impacts on the City of Renton's Sole Source Aquafer and other environmentally sensitive areas from the Wastewater Treatment Plant's sewage conveyance system, the applicant shall commit to design and construct several off-site sewage system improvement projects and associated local sewerage facility improvements related to the proposal. These shall Include: the Cedar River Trunk Relocation; the May Valley Interceptor Extension; and the Cascade Siphon/Footbridge. These projects will be subject to separate permitting and environmental review processes. Other system Improvement projects may be added by mutually written agreement of the City and Metro. The estimated total cost of the system improvement projects is $4,755,000 which will be borne solely by Metro. The City of Renton has agreed to reimburse Metro for design and construction costs associated with any local sewerage facility Improvements, after project completion In 1996. b) Additional Studies Required. Prior to the Issuance of any permits for Phase B construction the applicant shall submit and obtain City staff review of the following studies: (1) Generalized Utilities Plans. These shall consist of preliminary plan drawings and calculations for the following utilities: Storm and Surface Water Drainage. This shall identify the location and preliminary size of storm and surface water control facilities needed to meet all of the applicable Core and Special Requirements contained in Chapter 1 of the King County Surface Water Design Manual, which the City of Renton has adopted. Storm and surface water facilities should be preliminarily sized and shown schematically on the site plan. The plan must address prelmrpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June11, 1991 Page 13 methods for meeting water quality requirements for the impervious areas subject to storage of chemicals or vehicular use, prior to direct discharge to the Green River or ETS. Sewer. This shall consist of a report containing engineering calculations that demonstrates the City of Renton Wastewater Utility Department's requirement that surcharging of the Interceptors and adjacent City collector sewers around the Metro Wastewater Treatment Plant will not exceed two feet below the rim of any manhole (approximately elevation 13) within either the Metro or City of Renton systems. Water. This shall identify fire flow requirements (see Item No. 2 below) and watermain extensions and improvements such as hydrants, fire sprinkler systems, backFlow preventers etc. Proposed Improvements shall be shown schematically on the site plan. Plans shall show proposed improvements and utility relocations separately. (2) Fire and Emergency Management Plans/Special Operations Plan for Storage and Handling of Hazardous Materials. These plans shall address the following: Access. Primary and secondary access routes are to be maintained with prior approval of the City of Renton Fire Prevention Bureau Chief. Once established, these emergency access routes cannot be changed without Fire Prevention approval. Water. The applicant must coordinate all interruption of water supply serving hydrants and sprinkler systems with Fire Prevention. Fire Flow. The applicant shall provide sufficient information regarding building and facility construction to include: type of construction, total area in square feet, type of use including hazardous use of each building or facility. This analysis shall address the specific requirements regarding fire hydrants, fire suppression and alarm systems. Article 80 of the Uniform Fire Code. The applicant shall address compliance with Article 80 of the Uniform Fire Code regarding all storage and dispensing of existing and proposed hazardous materials. All hazardous materials operations at the Metro Wastewater Treatment Plant must meet minimums specified In Article 80 UFC. (3) Landscaping Plans. The applicant shall submit detailed landscaping development plans for the following: Detailed landscape Plan for Phase C internal Planting. This plan shall address proposed grading, plant materials and layout, and irrigation for the interior facility landscaping to be developed In Phase C. Detailed Landscape Plan for Additional Perimeter Landscaping in Phase C. This plan shall address the area along the site perimeter not included in the Phase A planting plan. This is the area along the Springbrook Creek between SW 7th Street and SW Grady Way. This plan shall Include proposed grading, plant materlals/layout and Irrigation. Implementation of this plan should occur In Phase C, or as soon as possible after adjacent facilities (Chlorine Contact Channel extension) are completed. Note to applicant: The applicant is encouraged to either undertake joint development of a public access trail on SOS C pmimrpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 14 property along the Springbrook Creek, or consider relocating the existing security fence to the upland side of the proposed trail, thus making it more accessible to the public. (4) Roadway Improvement Plan. The applicant shall provide Roadway Improvement Plans for Monster Road SW and the Longacres Drive. These shall run the full length of the property frontage. Plans shall Include, but not limited to, curb, gutters, sidewalks, and street lighting. (5) Traffic Signal Warrant Analysis. The applicant shall prepare a traffic signal warrant analysis for the Intersection of SW Grady Way and Longacres Drive. This intersection is presently at Level of Service E and should be upgraded to LOS D. (6) Transportation Management Plan. The applicant shall prepare a traffic control plan to be submitted to the City of Renton Transportation Division for construction activities. Proposed truck haul routes should also be coordinated with the City of Renton Police Department. Since Longacres Drive SW south of SW 16th Street Is a private road, the plan should address arrangements for use of this street. This should be coordinated with the Boeing Co. (7) Hold Harmless. The applicant shall hold the City of Renton Harmless from any liability should any of the above studies (1-6) result in increased project costs. It is also recommended that the applicant complete and submit these studies for City review, as soon as, possible in order to evaluate cost implications. g) Grady Way TBZ. The applicant shall participate in the Grady Way Transportation Benefit Zone pursuant to City Resolution No. 2827. This is estimated to be $44,091 [213 Increased vehicle trips x $207/trip], and should be paid at the time the building permit is Issued. h) Street Cleaning Bond. Prior to Issuance of a building permit, Phase B, the applicant shall post a $5,000.00 bond with the City for street cleaning during construction. i) Roadway and Infrastructure Repair. Metro shall repair or pay the City of Renton for the repair of any damage to roadways or infrastructure resulting from construction, prior to the Issuance of the final occupancy permit. j) Detailed Erosion Control Plan. Prior to issuance of the first permit for the project (Grading License), the applicant shall submit an erosion control plan for City staff review. This plan must be also be included in the applicant's construction contract for Phase A, Site Preparation. k) 2020 Plus Planning Participation. The applicant shall ensure City of Renton participation in all technical reviews of the Metro Wastewater 2020 Plus Study. Participation shall Include the City of Renton Public Works Director and representatives from the Wastewater Utility Section, Long-Range Planning, Current Planning and the Mayor's Office. I) Security Procedures. Security procedures should be established, in coordination with the City of Renton Police Department, for protection of the wastewater treatment plant, and particularly the outside storage of liquid chlorine and other hazardous materials. The applicant shall also notify Police and Fire In at least 24 hours in advance of any chlorine tank car movements, both inside and outside the wastewater treatment plant. 2. Shoreline Master Program Substantial Development Permit: a) The same conditions as specified for No. 1, Site Plan Approval, shall apply to this permit. pmlmrpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 15 3. Special Permit for Grading: a) The same conditions as specified for No. 1, Site Plan Approval, shall apply to this permit. 4. Routine Vegetation Management Permit: a) The same conditions as specified for No. 1, Site Plan Approval, shall be administratively applied to this permit. 5. NOTE TO APPLICANT: The above conditions do not absolve the applicant from the responsibility of meeting all City codes, ordinances and regulations. { p,MMrpl APPLICANT' S PROPOSED REVISIONS TO RECOMMENDED CONDITIONS Condition 1 (a) (Memorandum of Agreement Commitments: Delete, including subsections (1) - (3) . Condition l (b) (1) (Sewer Study) : Sewer. This shall consist of a report containing engineering calculations that demonstrates the City of Renton Wastewater Utility Department ' s requirement that surcharging of the interceptors and a4jaeent---C-� around the Metro Wastewater Treatment Plant will not exceed two feet below the rim Hof any manhole (approximately elevation 13 ) within �l the Metro systems. Condition 1 (b) (2) (Uniform Fire Code Compliance) : Article 80 of the Uniform Code. The applicant shall address compliance with Article 80 of the Uniform Fire Code regarding a4-1- the storage and dispensing ofand re �g __a chlorine and sulfur dioxide. All hazardous materials operations at the Metro Wastewater Treatment Plan must meet minimums specified in Article 80 of UFC as interpreted and implemented by the Renton Fire Marshall. Condition 1 (b) (4) (Roadway Improvement Plan) : Delete. Condition 1 (b) (5) (Traffic Signal Warrant Analysis) : Delete. Condition 1 (b) (7) (Hold Harmless) : Delete. 1 t Condition 1 (h) (Street Cleaning Bond) : Street Cleaning mod. Pr�aY T-=;- The applicant shall perform street cleaning during construction as may be necessary due to its construction activities. Condition 1 (1) (Roadway and Infrastructure Repair): Roadway and Infrastructure Repair. Metro shall repair or pay the City of Renton for the repair of any damage to roadways or infrastructure that can reasonably be attributed to Metro ' s construction activities r-e-s� prior to the issuance of the final occupancy permit. hny such damage shall be repaired to the condition that existed rior to the initiation of Metro ' s construction activities . Condition 1 (1) (Security Procedures) : Security Procedures . Security procedures should be established, in coordination with the City of Renton Police Department, for protection of the wastewater treatment plant, and particularly the outside storage of liquid chlorine and other hazardous materials. The applicant shall also notify re! ee anu the Fire Department as soon as possible after learning of a chlorine tank delivery or when moving chlorine tank cars within h bat ; tea 9f the wastewater treatment plant. 2 RECOMMENDED CONDITIONS Metro accepts most of the conditions recommended in nth staff some report on . pages 12-15 _ Metro disagrees , conditions that it believes are not necessary to mitigate project impacts and requests that a few others be clarisind the condWe itions like to submit as an exhibit our proposal recommended in the staff report. Additions are underlined and deletions -1'--9 del" 4 Metro disagrees with subsection (a) and Condition 1 (al - project subsections (a) (1) - (3 ) of condition 1. These are voluntary p 7 mitigation measures that Metro has agreed to with Renton in the Memorandum of Agreement.Therefore, relft to scommitmentsures are o should 1not be mitigate impacts . imposed as permit conditions. They are enforceable by Renton through the Memorandum of Agreement, separate and apart from the issuance of permits, in the context of the reciprocal obligations set forth in that agreement. We therefore propose that be bsection (a) of condition 1 , including subsections ( ) - ( ) entirely- Condition 1 (b) (1- Metro will study surcharging of interceptors in the vicinity of the treatment plant, but does not address surcharging in the adjacent City have authority to collector sewers. We th b erefor dpto �eadse tastfollows the cond paragraph of subsection 1 (b) ( ) Sewer. This shall consist of a report containing engineering calculations' that demonstrates the City of Renton Wastewater Utility Department' s requirement that surcharging of the interceptors around the Metro Wastewater Treatment Plant will not exceed two feet below the rim of the manhole (approximately elevation 13) within `n = f-41err n systems_ Metro .rr—��i Condition 1 (b1 (2).. Metro requests that the last paragraph in subsection (b) (2 ) be revised to clarify a couple of points . First, the phrase all storage and dispensing of existing and proposed hazardous materials" is confusing and unclear. The City ' s comments to Metro during EIS preparation and permit processing dealt with upgrading the chlorine and sulfur dioxide storage buildings . We suggest that the condition be modified to reflect this Second, the Uniform Fire Code (UFC) grants the Fire Marshall discretion in interpreting and implementing the requirements of the code. e and the Fire Marshall have worked well together up to this point- We want to ensure that this condition does not curtail the Fire Marshall ' s exercise of such discretion. wethereforee e pro ose read has the last paragraph of subsection (b) (2) be follows : Article 80 of the Uniform Code. The applicant shall address compliance with+ Article 80 of the Uniform Fire Code regarding a-1 1 the storage and dispensing of e 7 chlorine and sulfur dioxide. All hazardous materials operations at the Metro Wastewater Treatment Plant must meet minimums specified in Article 80 of UFC as interpreted and implemented by the Renton Fire Marshall. Condition 1 ( . Metro disagrees with the requirement to bl(41_ improve Monster Road SW and Longacres Drive at this time. Along the side of Monster Road adjacent to the plant is a very steep downward slope, which will require a large amount of fill and stabilization control measures to contain. The result will only an improvement on one side ide of the road (according to the code, tion, we even though the condition is not so limited) .should be improved;In a; previous question whether the road correspondence by the Renton Department of Public Works , which we would like to submit as an exhibit, suggests otherwise. We suggest instead that the City reconsider whether this road must be improved, and if so, whether it would be more reasonable to involve other adjacent property owners so that the entire road can be improved. Finally, we suggest that insofar as this condition relates to a code requirement, that it be deferred to the building permit process so that we can preserve our opportunity to request a variance. The reference to improving Longacres Drive is inappropriate because it is privately owned, which the City acknowledges in subsection (b) (6) of this condition. We therefore request that this subsection be deleted in its entirety from these permits . Condition I (b) 151 - We disagree with the requirement to ,'conduct a traffic signal warrant study or otherwise upgrade the intersection of SW Grady Way and Longacres Drive to Level of Service D . These requirements are not based on any findings by the City that Metro ' s project will significantly impact this intersection. The supplemental EIS notes that this intersection is at Level of Service E whether or not Metro ' s project occurs . Furthermore, the supplemental EIS concludes that the enlarged plant will not cause a significant increase in truck traffic during operation. Temporary construction truck traffic will be controlled through use of flaggers . it is inappropriate to require Metro as a condition of its permits to shoulder the expense and responsibility for studying or upgrading this intersection. We therefore request that this subsection be deleted entirely. Condition 1 (b) (7) . Although we are not exactly sure what this provision is supposed to accomplish, we disagree with any attempt to require, as a permit condition, that Metro hold harmless the City from any liability. We therefore request that this subsection be deleted entirely. Condition 1 (h) - Although Metro fully intends to perform necessary street cleaning due to its construction activities , we do not understand why a $5 , 000 bond must be posted. The City has not, been able to cite to u any specific authority for this requirement. If there is no ruch authority, we request that this condition be revised to eliminate the bond requirement as follows : 8 Street Cleaning $e-Ad f • _ c Lc The applicant shall Perform street cleaning during construction as may be necessary due to its construction activities . Condition 1 ( i) . Metro does not disagree with the intent of this condition, but we believe it is too open-ended as written . Metro will take responsibility for any damage that can reasonably be attributed to its activities. Also, Metro will repair any such roadways or infrastructure to the condition before Metro ' s construction activities began. We therefore suggest that this subsection be amended as follows : Roadway and Infrastructure Repair. Metro shall repair or pay the City of Renton for the repair of any damage to roadways or infrastructure that can reasonably be attributed to Metro ' s construction activities r = }= - prior to the issuance of the final occupancy permit. Any such damage shall be repaired to the condition that existed prior to the initiation of Metro ' s construction activities . Condition 1 (1) . Metro does not object to providing notice prior to chlorine tank car movements , but it cannot give 24 hours advance notice. It is important to realize that Metro does not completely control the delivery of chlorine tank cars . Metro is informed when a chlorine tank car will be delivered sometime during the next 5 to 15 days . On the day of delivery, Metro receives only . 1-2 hours advance notice. Also, many tank cars containing chlorine and other materials pass by the treatment plant along the railroad tracks to other destinations . It would be impossible for Metro to provide notice about all chlorine tank cars outside of the treatment plant. Finally, we wonder whether it is necessary to notify both the fire and police departments . We therefore request that this subsection be amended as follows : Security Procedures. Security procedures should be established, in coordination with the City of Renton Police Department, for protection of the wastewater treatment plant, and particularly the outside storage of liquid chlorine and other hazardous materials _ The applicant shall also notify Pel "-"' the Fire Department as soon as possible after learning of a chlorine tank delivery or when moving chlorine tank cars within atleast 21 Cana , tank ear mro� ` a3c�e- and oi�ts3d��£= the wastewater treatment plant. RESPECTFULLY SUBMITTED this llth day of June, 1991 . MUNICIP LITY OF METROPOLITAN SEATTLE Gerr . e Jackson Right- f_Way Agent 0 I r.• .h. 7.2 AJsANDO/vED � n � I . r l P � 0 I M: .E. t I P . 01ti-5 -A I L a � . ` iI(t(1tI1T I 1 _ 4. •1 a � � . s` .. 11 Jt ,6 1 � / I 111111 I � I I Municipality of Metropolitan Seattle SA;SM;SP-040-91 APPLICANT TOTAL AREA an 5 arras ICANT M PRINCIPAL ACCESS SW Grady Way Via Monster Road SW or Oakesdale Ave SW Via 55�7th St over P-1 Channel EXISTING ZONING P-1 Public Use EXISTING USE Metro Waste Water Treatment Plant PROPOSED USE PJetro Waste Water Treatment Plant, Expansion III COMPREHENSIVE LAND USE PLAN Public/Quasi-Public COMMENTS Located @ 1200 Monster Road SW, Renton 9VFLS JIaYKrcxK y I. l � 1� I 1j 1 I•I _ II . \ {� ��{ �/ i L.✓ — F i ;i1// .3. .. A 4`, onwrt A� 2 s j _- -A� to YE1XO REAM&,REAIMwi R T IN NwTp "METRO BC cn9ml0.M0 Rex m .1 l F.QUM w MMNT II �� .%v.�sj'� IM .LY 20. 1991 ru.rsn au%(urRa twn W .:/ ::' R•��xl .: � 4EY: l - ' WW oo ' ' i} .,K4R1 NYYV.LMw 1 i ' .Y _ - rtRR wE RERRERCE. - ;+j� - fit. b'..i�.- EeRWt wnssr...c caxsmucnox scauERa J �tUW m E r A o BC E%iS1 C m0 EW MEAn CNI W ESERE� �` .�.�j:♦ ENI GC Evr 11 cWSTRUUO1 w3YxC INTERIM LANDSCAPING CHLORINE BUILDING ORDINARY HIGH WATER LINE P-1 CHANNEL ' DIGESTERS OAKESDALE ROAD— SHORELINE JURISDICTIONAL BOUNDARY tiff w WETLAND WATERTOWER t. 1 ADMINISTRATION BUILDING •'`L J ! ��,,_��' � ' MONSTER ROAD - `"�• r - ly_. '•y'' FACILITY ENTRANCE uncE oenouovs YEDIUY DEVGUVU TREE h OSWLL GEnOVGVS TREE ...1.` LARGE FYERGRFEX TREE EVERGREEN TREE E EIOUIE i] ' CCIKEPTIIAL RANTK FLAX yETRp TPE,ETM1?puHF AT IEENEFIR „MEYRE3 1 I 31 II - I 1. AFT Is I i ' L I iWM„NKhR I � I J• .i y i�r � woes 8� KE) I i I I j i i �—�� •9,41I�A I' I I � pp V�—R.Nw I I L I i I i m ! I ! � I °qF tlnC p4 PF 4' �4 4 CITY OF RENTON MEMORANDUM DATE: June 12,1991 TO: Fred Kaufman, Hearing Examiner FROM: Don Erickson, Zoning Administrator Paul Forsander, Staff Contact SUBJECT: SA; SM; SP; 040-91 Metro Waste Water Treatment Plant, Expansion III Additional Departmental Comments The following Departmental Comments were prepared in response to testimony and questions raised at the Public Hearing held on June 11, 1991 for the above referenced project: 1. Phased Site Plan Approval. The discussion of phasing contained in the Preliminary Report was meant to Imply a request for phased approval of the project per Section 4-31- 33 J. The proposal meets the qualifications for phased approval; it is a large project and it would be developed over a period of years exceeding the time limits of subsection I. The proposal clearly defines phases and the time limits for each phase. The request should, therefore, be modified to provide for Phased Site Plan Approval. It is our recommendation that the Hearing Examiner decide in favor of the Site Plan Approval subject to the Phasing and Time Limits specified in the Preliminary Report (page 1). 2. Adequacy of Application for Special Permit for Grading. The adequacy of the application with respect to drainage control for grading was questioned. Section 4-10-7 (E) 5 Drainage Control states: Detailed Plans of all surface and subsurface drainage devices, walls, cribbing, dams and other protective devices to be constructed with, or as a part of, the proposed work, together with a map showing the drainage area served by any drains, and measures to be taken to control erosion and the estimated time of planting or Installation of controls. The application for Special Permit provides the following information relating to the requirements outlined above. The applicant's narrative (Contained in Exhibit I,Attachment No. 1, Book 2) discusses proposed erosion control practices (pp. 27-30). Sheet G-6 provides two details showing the proposed erosion control device (Detail A) and landscape protection device(Detail B). On Sheets G-63 and G-66, the applicant shows the proposed location and extent of the erosion control devices. On June 12, 1991, the applicant submitted required documents for the Annual Grading License,which is the construction permit for Phase A Site Preparation. These documents contain additional information regarding drainage and erosion control measures. Sheet G- 41 of the Annual Grading License submission shows the proposed drainage and erosion control plan. Sheet G-6 shows erosion control details. Section 02475 of the Technical Specifications describes the technical requirements and methods which will be included in the construction contract for the project. The Building Department has received the Temporary Erosion Control Plan for the project, and has just begun the technical review for the Grading Permit (Annual License). The department will complete its technical review of the permit drawings and specifications within the next two weeks. Metro has indicated it will revise the final drawings and technical specifications for the Annual Grading License, as required, to respond to City comments. Preliminary review of the submission for Annual Grading License Indicates that the temporary erosion control plan needs some revision to fully comply with the City's Storm Water Ordinance (ling County Surface Water Design Manual) regarding facility requirements and level of detail. The Plan Review Section is confident that these issues can be resolved during the review of the construction grade submittal drawings for the Fill & Grade Permit, which will be issued through the Building Department. construction permit will not be issued by the Building Department until the plan is in full ompliance with City Code requirements .f The application satisfies all of the submission requirements (plans and specifications) for the Special Permit for Grading. Therefore, it is our recommendation that the Hearing Examiner approve the Special Permit for Grading, with the conditions contained in the Preliminary Report. 3. Fire and Emergency Management Plans/Special Operations Plan for Storage and Handling of Hazardous Materials/Security Procedures. Article 80 Uniform Fire Code The Fire Department opposes the applicant's proposed revision to the recommended condition regarding compliance with Article 80 of the Uniform Fire Code. Administration of Article 80 is at the discretion of the City of Renton Fire Marshall. Because the type and extent of existing and proposed hazardous materials (in addition to Chlorine and sulfur dioxide) is not known, the Fire Department requests that the applicant prepare a report which discloses all hazardous materials and proposed handling procedures in compliance with Article 80 of the Uniform Fire Code. This report shall include a survey documenting the type, quantity and location of all hazardous materials. It shall also Identify the type, quantity and location of all hazardous materials in the proposed facility expansion. Finally, the report shall discuss compliance of existing and proposed facilities, and upgrade measures necessary for full compliance. The applicant's report on compliance with Article 80 shall also address current compliance of the Chlorine Building and proposed upgrade measures necessary to achieve full compliance. The report on compliance with Article 80 UFC shall be reviewed by the City of Renton Fire Marshall. Security Procedures The applicant's request for single notification of Police and Fire through the City's Emergency Communications Center (911) is satisfactory. It is recommended, however, that this condition require that the applicant work with the Police and Fire Departments to develop procedures for coordination and notification of chlorine rail tank car movements. 4. Response to Applicant's Proposed Revisions to Other Conditions: a. Condition 1 (a) regarding the Memorandum of Agreement should remain because the Site Plan Approval must be based upon to Mitigation of Impacts to Surrounding Properties and Uses and Impacts of a Proposed Site Plan to the Site. b. Changes to condition 1 (b) (1) regarding the Sewer Study are acceptable. C. /1 Condition 1 (b) (4) regarding the Roadway Improvement Plan is not acceptable since this is a Code requirement 4-24-3 (1). d. Condition 1 (b) (5), Traffic Signal Warrant Analysis, is required by code 4-24-3 (1) and 9-12-8 (c), as well as, Public Works Departmental Policies. e. Proposed modification of condition 1 (h) relating to the Street Cleaning Bond is not accectable. The applicant shall be required to post a $5,000.00 bond for street cleaning during construction. This is Department of Public Works Policy, and is required of all applicants prior to issuance of any construction permit. f. Proposed modification of condition 1 (i) Roadway and Infrastructure Repair is satisfactory. g. The Hold Harmless condition 1 (b) (7) may be deleted since the applicant has acknowledged that all plans require for Phase B submissions (Condition 1 b.) must meet City Code requirements. The following Departments have reviewed this memorandum and concur with the recommendations contained herein: �., �lint E. Morgan Transportation-Development Services Randall L Parsons P.E. Storm &Waste Water 'a Penny Bryant Police Jim Gray for Gary Gotti Fire Prevention Gregg Zimmmerman Plan Review CITY OF RENTON MEMORANDUM DATE: June 14, 1991 TO: Fred Kaufman, Hearing Examiner FROM: Paul Forsander wvlac l"'� SUBJECT: SA; SM; SP; 040-91 Metro Waste Water Treatment Plant, Expansion III Additional Clarification Regarding Phased Site Plan Approval In the June 12, 1991 memorandum to you, Don Erickson and I recommended in favor of Phased Site Plan approval for the Metro project. The question came up in the June 11 Hearing as to the process for review of potential future modifications to the site plan. Section 4-31-33 F defines Major Adjustments to an approved site plan: Major adjustments to an approved site plan require an amended application pursuant to subsections 4-3133 C through G. The review and approval shall rest with the approval body which approved the original site plan. Major adjustments involve a substantial change in the basic site design plan, intensity, density, use and the like generally Involving more than a ten percent (10%) change in area or scale. Based on review of the Metro project and its proposed site plan, I believe it Is very unlikely that there will be any major modifications or adjustments to the approved site plan and its approved phases. For example, the location, size and design of major structures and facilities such the Secondary Clarifiers is unlikely to change since the proposed expansion is a replication of similar structures in the existing plant. Adjustments to the proposal could be expected to occur in areas of utilities which would be located below grade. For example, minor utility adjustments may be required to respond to City Code requirements In areas such as Fire Flow or Surface Water, based on technical review for the construction permits. In the event that the applicant proposes major modifications to the basic site design plan, that is changes to structures and site features exceeding the ten percent(10%) guideline specified in 4-31-33 F, than it will be required to submit an Amended Application for Site Plan Approval for Public Hearing before the Hearing Examiner. CITY OF RENTON HEARING EXAMINER E: PUBLIC HEARING AGENDA COMMENCING AT 9:00 AM, JUNE 11, 1991 COUNCIL CHAMBERS, SECOND FLOOR, RENTON MUNICIPAL BUILDING The application(s) listed are in order of application number only and not necessarily the order in which they will be heard. Items will be called for hearing at the discretion of the Hearing Examiner. PROJECT NAME: Metro Wastewater Treatment Plant, Expansion III PROJECT NUMBERS: SA;SM;SP-040-91 PROJECT DESCRIPTION: Three phase implementation of Metro Wastewater Treatment Plant Expansion III at Renton: One: Site Preparation (excavation, fill and grading) and Perimeter Landscaping; Two: Facility Construction; Three: Interior Landscaping and Site Clean-Up. The project is located at 1200 Monster Rd SW. DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS -/ij All PRELIMINARY REPORT TO THE HEARING EXAMINER PUBLIC HEARING APPLICANT: Municipality of Metropolitan Seattle (Metro) PROJECT NAME: Metro Wastewater Treatment Plant, Expansion III FILE NUMBER: SA;SM;SP-040-91 LOCATION: SEC: 24; TWMSHP: 23N; RNG: 4E 1200 Monster Rd SW, Renton A. SUMMARY AND PURPOSE OF REQUEST: The applicant (Metro) seeks to obtain: a) Site Plan Approval and Shoreline Master Program Substantial Development Permit to expand facilities at the existing Metro Wastewater Treatment Plant, thus increasing secondary treatment capacity from 72 million gallons per day (mgd) to 108 mgd; b) Special Permit for Grading (Excavation, Fill and Grading); and c) Routine Vegetation Management Permit [Note: the Routine Vegetation Management Permit is subject to administrative review and approval, and is included in this report for informational purposes] to allow preparation of the site for construction prior to issuance of a building permit. The proposed expansion would occur in three phases: Phase A (1991-1993): Site Preparation (vegetation clearing, excavation, fill, grading and site dewatering) and Perimeter Landscaping; Phase B (1993-1996): Facility Construction; and Phase C (1996): Interior Landscaping and Site Clean-Up. B. GENERAL INFORMATION: 1. Owner of Record: Municipality of Metropolitan Seattle (Metro) 2. Applicant: Municipality of Metropolitan Seattle (Metro)/Gerrie Jackson 3. Existing Zoning: P-1, Public Use 4. Existing Zoning In the Area: City of Renton Zoning: B-1, Business Use; M-P, Manufacturing Park; L-1, Light Industry; O-P, Office Park; P-1, Public Use; City of Tukwila Zoning: RA, Agricultural; C-2, Regional Retail; M-1, Light Industry. 5. Comprehensive Land Use Plan: Public/Quasi-Public 6. Size of Property: 84.5 Acres 7. Access: SW Grady Way Via Monster Road SW or Oaksdale Ave SW Via SW 7th St Bridge over Springbrook Creek. 8. Land Use: Metro Wastewater Treatment Plant 9. Neighborhood Characteristics: North: Undeveloped (Proposed Office Park) East: Office Park and Springbrook Creek South: Industrial and 1-405 West: Industrial and Black River Channel prelmrpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 2 C. HISTORICAL/BACKGROUND: Action File Ordinance Date Annexation 1745 4-14-59 Amend. Ord. 1764 5-27-59 Amend. Ord. 1928 12-22-61 Special Permit SP-065-81 Special Permit SP-006-83 Conditional Use CU-007-83 Substantial Shoreline SM-107-83 Variance V-045-84 Conditional Use CU-087-84 Variance V-088-84 Substantial Shoreline SM-118-84 Rezone R-046-85 3961 12-13-86 Shoreline Exemption SME-003-85 Site Plan Approval SA-061-87 Special Permit SP-062-87 D. PUBLIC SERVICES: 1. Utilities a. Water: A number of private (Metro) 12-Inch water lines serve the site. These mains interconnect with the City of Renton Water System. b. Sewer: A 12-Inch sanitary sewer serves the site perimeter (see attached map). There are a number of Metro-owned sewers on-site. C. Storm Water Drainage: Existing storm water runoff from impervious surfaces Is collected and discharged to the Green River. Future runoff from the proposed expansion will also be collected, treated on-site and discharged consistent with National Pollutant Discharge Elimination System (NPDES) permit requirements and other applicable regulations, such as the City of Renton's adoption of the King County Surface Water Design Manual. 2. Fire Protection: Provided by the City of Renton as per ordinance requirements. 3. Transit: Not Applicable 4. Schools: a. Elementary Schools: Not Applicable. b. Middle Schools: Not Applicable. C. Hlgh Schools: Not Applicable. 5. Recreation: City of Renton Parks: Earlington Park is 0.80 miles north of the site; Lake Street Park is one mile southeast of the site; and Oakesdale Park (Springbrook Creek) is Immediately adjacent to the site. City of Tukwila Parks: Fort Dent Park is approximately 500 feet west of the site; Foster Golf Course lies northwest of Fort Dent Park, approximately 0.75 mile from the site. E. APPLICABLE SECTIONS OF THE ZONING CODE: 1. Section 4-31.9, Public Zone (P-1). 2. Section 4-31-33, Site Plan Review. 3. Section 4-31-34, Landscaping. prelmrpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 3 4. Section 4-31-27, Mining, Excavating and Grading. 5. Section 4-9, Land Clearing and Tree Cutting Ordinance. F. APPLICABLE SECTIONS OF THE COMPREHENSIVE PLAN OR OTHER OFFICIAL CITY DOCUMENT: 1. Valley Planning Area, City of Renton Comprehensive Plan. 2. Policies Element,VIII - Utilities Goal, D. Sanitary Sewers Objective, City of Renton Comprehensive Plan Compendium, 1986, pp 22-23, 3. Policies Element, III - Urban Design Goal, C. Landscape Objective City of Renton Comprehensive Plan Compendium, 1986, pp. 10-11. 4. Shoreline Master Program, City of Renton,Adopted by Ordinance No. 3758. 5. Grady Way Transportation Benefit Zone,Adopted by City Resolution No. 2827. G. DEPARTMENT ANALYSIS: 1. BACKGROUND The applicant is seeking Site Plan Approval, a Shoreline Substantial Development Permit,a Special Permit for Grading, and a Routine Vegetation Management Permit [Note: the Routine Vegetation Management Permit is subject to administrative review and approval, and Is included In this report for informational purposes only] to allow construction for expansion of the existing Metro Wastewater Treatment Plant located at 1200 Monster Road SW. The existing regional wastewater treatment facility presently handles 72 mgd under average wet weather flow. The proposed expansion would Increase the total capacity to 108 mgd (average wet weather flow). While the plant capacity of 108 mgd would be completed in 1996, it is estimated that capacity would not be reached by the Metro system until approximately 2005. The proposed expansion would occur in three phases: Phase A (1991-1993) would consist of Site Preparation (Excavation, Fill, Grading and De-Watering) and Perimeter Landscaping; Phase B (1993-1995) would consist of Facility Construction; and Phase C (1996) would consist of Site Clean-Up and Internal Landscaping. [Please see Attachment No. 1 for applicant's narrative containing detailed project description.] Metro evaluated four treatment facility layout alternatives for the Renton Facility in Its recent Supplemental EIS for the proposed expansion (see No. 2 below for discussion of EIS). Alternative 2 was selected as the preferred alternative. This alternative increases plant capacity by upgrading and enhancing the existing treatment facilities and by constructing additional tank structures and other facilities totalling approximately 165,000 sf. Proposed new structures would include: Four(4) Primary Sedimentation Basins; One (1) Four-Pass Aeration Basin; Four(4) Secondary Clarifiers and Associated Channels; Two (2) Dissolved Air Flotation Thickeners with Odor Reduction Tower; One (1) Digested Sludge Blending Tank; and One (1)Waste Gas Burner. Channels and pipelines necessary to convey various process streams to and from process units will also be constructed. All proposed construction would occur within the site boundaries of the existing wastewater treatment plant. The existing plant was constructed by Metro in three stages: 1) The original plant was constructed in 1966 with a capacity of 24 mgd; 2) the first expansion was completed in 1974 (Note: the first expansion was approved as part of the original plant permit) Increasing the plant capacity to 36 mgd; and 3) the second expansion was completed in 1988 (Note: approvals for the second expansion occurred between 1983 and 1987), which increased the plant capacity to Its present 72 mgd, and also completed the Effluent Transfer System (ETS) to Elliott Bay. With the completion of the ETS pipeline, effluent discharge was discontinued to the Green River and final effluent was discharged to the marine waters of Puget Sound. This proposal will be the third expansion of the plant, hence It Is named Metro WasteWater Treatment Plant, Expansion III. The existing plant layout and site plan have the capacity to accommodate additional future expansions to achieve an ultimate capacity of approximately 250 mgd. The need for future plant expansions will be addressed in Metro's "WasteWater 2020 Plus" study which is scheduled pwimrpt PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 4 for completion in the mid-1990's. The 2020 study will determine if additional enlargements of the regional treatment plant at Renton are required or whether increased flows should be accommodated by other means, such as new treatment plants or service area changes within the Metro service area. Approximately 6 acres of the plant site lie within Renton's Shoreline Management district, which extends 200 feet westward from the line of the high water mark in Springbrook Creek/P-1 Channel. Work within the shoreline area relates to berming and landscaping, construction of two of the Secondary Clarifiers, extension of the Chlorine Contact Channel, minor roadway Improvements, and development of a perimeter trail (for guided tours) adjacent to the existing and security fence along the Springbrook Creek. This trail would not be accessible to the public without checking in at the Administration Building and an escort from Metro. Soil excavation for facility construction will Involve approximately 260,000 cubic yards. About 100,000 cubic yards of this soil will be used for fill material for proposed perimeter landscaped berms, unless the soil proves to be contaminated. In addition, approximately 45,000 cy, of clean topsoil will be Imported for landscaping. Remaining excavated soil will be stockpiled for backfill following facility construction and for grading for proposed Internal landscaped areas. Preliminary soils analyses does not Indicate the presence of contaminated soils. If encountered, contaminated soils would be transported and disposed of off-site. Approximately 35,000 cy. of clean structural backfill will also be Imported to the site. There will be additional off-site disposal of construction debris, consisting of about 160,000 sf of pavement and 7700 If of curb and gutter. Construction of facilities will also require dewatering of portions of the site, particularly during Phase A, Site Preparation. Excavation for proposed treatment facilities will extend below the level of groundwater, thus necessitating selective dewatering. The proposed groundwater dewatering system would utilize large diameter area wells. These wells would be operated In conjunction with recharge wells located near existing structures on- site to minimize potential settlement. Preliminary studies Indicate the need for dewatering rates of up to 5,000 gpm to control groundwater in deeper excavations. Should the groundwater prove contaminated, it would be treated on-site and discharged via the Effluent Transfer System (ETS). There will be minimal road circulation and parking improvements on-site. The two access roads on the west side of the site, and the road along the administration building will be replaced with one access road. Roads adjacent to the Sludge Dewatering Building will be reconstructed for increased radii for truck turning and reduced slope for better winter Ice conditions. The turning radii of several roads on-site will be revised to accommodate wide turning trucks. Approximately 35 additional parking spaces will be constructed along the existing Chlorine Contact Channel. Significant landscaping is proposed for the site to provide visual buffering along the Springbrook Creek and to breakup large open internal areas that are not scheduled for development in this expansion. The landscaping and site plan layout is designed to eventually create a campus-like appearance and to relate to neighboring office park development. It will probably take five years for the landscaping to reach maturity, thus the planned effect should be In place by 1996 for the Perimeter Landscaping and 2000 for the Interior Landscaping. Perimeter berms and landscaping are proposed for construction during Phase A. Internal landscaping is proposed in Phase C. Metro is proposing that the Internal Landscaping be considered as "temporary' and would be subject to removal to allow for future facility construction to meet future needs identified In the 2020 Plus study, and, subsequently,approved by the City. There are two small wetland areas, of approximately 2 acres, at the northern most portion of the site, which will not be affected by this proposal. These wetland areas will be protected during construction and project operation by a fence and a 25 foot wide buffer strip. 2. ENVIRONMENTAL ANALYSIS Metro, as lead agency for the proposed action, prepared an EIS for the project. [See Attachment No. 21 The EIS was a Supplemental EIS which supplements the environmental reviews for wastewater treatment plant expansion which were completed in 1981 and 1986 by Metro. The Supplemental EIS is a project-level EIS for expanding Metro's facilities at PMM'Pt PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 5 Renton to treat up to 108 mgd. According to Metro, the EIS was used to select a final layout for implementing the expansion of the wastewater treatment plant, and to support application for project permits. Metro invited public participation during the planning and environmental review process. Metro conducted several public scoping meetings during January and February, 1991. A Determination of Significance (DS) and scoping notice announcing its Intent to prepare a Supplemental EIS on the project was Issued by Metro on January 11, 1991. Approximately 500 scoping notices were distributed during a comment period of four weeks. The draft supplemental EIS was issued on March 22, 1991, with the public comment period extending through April 22, 1991. Metro held two informational public meetings, followed by formal public hearings in the Renton City Council Chambers to receive comments on the draft EIS. Approximately eight citizens attended the first public hearing and asked questions during the Informal presentation about the project. No one commented during the formal public hearing. A second public hearing was held with four citizens attending. Only one person commented during the formal public hearing. That person spoke in favor of the project. Metro's environmental compliance division received a total of seven comment letters on the DSEIS: four letters from agencies,two letters from citizen groups, and one letter from a neighboring business. Comments primarily focused on the issues of aesthetics, noise, traffic, odor and potential impacts to the great blue herons. The City of Renton had extensive comments on the DSEIS. [See Attachment No.3 for City of Renton Comments.] The Final Supplemental EIS was Issued on May 24, 1991. The Final EIS was revised in response to written comments received during the public comment period. Mitigation was proposed in the FSEIS In response to City of Renton and other comments. Based on the FSEIS, Metro has committed to implement specific mitigating measures. These are contained in Exhibit B of the "Memorandum of Agreement" between Metro and the City of Renton. [See Item 3 below for discussion of Memorandum of Agreement.] Differences between the FSEIS and the Proposal. Because of budget limitations, the expansion contained in this proposal has been scaled down from Alternative Two described in the FSEIS: Only four (4) of the eight (8) Secondary Clarifiers would be constructed, and there would be no anaerobic digester constructed. The remaining facilities,will be reviewed as a separate application after 1996. 3. MEMORANDUM OF AGREEMENT The Memorandum of Agreement (MOA) between Metro and the City of Renton was created to resolve Metro's objective to begin construction of the proposed expansion in mid-August 1991 and address the City's concern over potential environmental impacts, particularly in areas of wetlands and environmental health. To that end, Metro and the City of Renton have entered Into an agreement which formally defines mitigation, compensation and other project requirements. Under the terms of the MOA, Metro has committed to implementing specific mitigation measures, construction of Metro conveyance system Improvements, and the funding of wetland/wildlife enhancement and community facilities. Also under the terms of the MOA, the City of Renton has agreed to use its best efforts to expedite project review for permits to allow Metro to begin construction by mid-August 1991. Mitigation measures, which Metro and the City of Renton agreed to, are contained in Exhibit B of the attached Memorandum of Agreement [Attachment No.4]. Under the Mitigation and Compensation section of the MOA(Section 4), Metro has agreed to fund up to $3,500,000 for the acquisition of riparian wetlands and uplands that could serve as habitat for wildlife within 2500 feet of the plant boundary. These wetland/wildlife Improvements shall be permanently dedicated to the public for the purposes of wildlife preservation and enhancement, including possible use by the City for interpretive trail purposes. Under the Mitigation and Compensation section of the MOA, Metro has also agreed to fund $2,500,000 for public service and community improvements within the City of Renton. These Improvements would enhance the City's ability to respond to emergencies p,.I.rpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 6 occurring at the wastewater treatment plant, such as a fire, explosion, hazardous material spill or chlorine leak. These could consist of various types of Improvements such as a City fire station and/or emergency response training facility. Metro has also agreed in Section 5 of the MOA to construct several off-site sewage conveyance system Improvement projects related to the proposal. These Include: the Cedar River Trunk Relocation; the May Valley Interceptor Extension; and the Cascade Siphon/Footbridge. These projects will be subject to separate permitting and environmental review processes. Other system Improvement projects may be added by mutually written agreement of the City and Metro. The estimated total cost of the system Improvement projects is $4,755,000 which will be solely borne by Metro. The City of Renton has agreed to reimburse Metro for design and construction costs associated with any local sewerage facility improvements. The commitments outlined above are contingent upon Metro becoming legally entitled to begin Phase A construction by mid-August 1991. However, even If Metro is not legally entitled to proceed with construction on its site by mid-August 1991, but the City has become legally obligated to purchase Wetland/Wildlife improvements, Metro has agree to remit these funds to the City for a period of up to 12 months. 4. DEPARTMENTAL COMMENTS Various City departments have reviewed and commented on the proposal. The majority of departments recommended approval of the proposed Metro Wastewater Treatment Plant, Expansion III with conditions. Comments are attached. The context of these comments and recommended conditions Is addressed in the text at the end of this report. 5. CONSISTENCY WITH SITE PLAN REVIEW CRITERIA: Section 4-31(d)(1) lists ten criteria that the Hearing Examiner is asked to consider along with all other relevant Information in making a decision on a Site Plan Approval application. These include the following: a) Conformance with the Comprehensive Plan its elements and policies: The Renton Comprehensive Plan designates the subject site as "Public/Quasi- Public" to which this project fully complies. The use of the subject site as a municipal utility has long been established in a series of land use actions starting In 1965. Initial projects of the second expansion of the Wastewater Treatment Plant were approved on July 12, 1983, by Conditional Use Permit, File No. CU- 007-83, and the remainder of the second expansion was subsequently approved on October 22, 1987, File Nos. SA-061-87, SP-062-87. The proposed Expansion III contained in this application is an amendment to the earlier land use applications. The proposal is consistent with the applicable general goals, policies and objectives of the City's Comprehensive Land Use Plan, and the area specific policies of the Green River Valley Plan. Specific goals which apply to this project Include: Land Use: To promote development of the Valley in a diversity of high quality industrial uses, together with commercial and office uses; Environmental: To ensure that development of the Valley is harmonious with the natural environmental setting, while minimizing pollution and other adverse environmental Impacts; and Urban Services: To promote the adequate provision of utility services (including storm drainage control), community facilities, and recreational opportunities in the Valley. The proposal is also consistent with the Utilities Policies which specifies that Development within the Valley should be served by adequate utilities. b) Conformance with existing land use regulations: The subject property is zoned: P-1 (Public Use). This zone requires the reviewing body to ascertain and determine that 'the general design and development conform with the adjacent surroundings, meet applicable building and zoning code requirements, comply with the Comprehensive Plan, and has adequate and safe traffic circulation and access." The proposed site plan generally addresses the development standards required for this zone. Minor modifications of the plans may be allowed to achieve full compliance with the Site Plan Review Ordinance(4-31-33). pmlmrpt PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 7 c) Mitigation of Impacts to surrounding properties and uses: The proposal Includes actions to minimize potential impacts on surrounding properties. A list of mitigating measures which Metro has agreed to are contained In the Memorandum of Agreement for the project. The MOA also includes other actions, which Metro has agreed to Implement, for wetland/wildlife enhancement and community/public service facilities, and Metro conveyance system improvements. Perimeter berming and landscaping are proposed to help screen and buffer the plant facilities from uses In the surrounding neighborhood. Interior landscaping Is also proposed to visually breakup large open areas. Exterior lighting will be shielded from adjacent properties. Modifications are proposed to existing and new facilities to control odors to meet a design standard of five odor units at the plant's property boundary. Examples of odor control modifications Include: ventilation and pre-chlorination of the influent sewer; taller stack for exhaust from the Raw Sewage Pump Station; covering and ventilating liquid treatment processes; enclosure and exhaust scrubbing of the Grit Cyclone Building; reduction of foul air emissions from digesters; and odor scrubbing and taller dispersion stacks from other facilities. Acoustical treatment has been Incorporated into the design of facilities for noise control. Construction activities will be controlled to minimize noise Impacts. For example, construction hours would be restricted to 7:00 a.m. to 7:00 p.m., weekdays. d) Mitigation of impacts of the proposed site plan to the site: The proposed site plan was designed to minimize on-site Impacts. The plan Includes extensive perimeter and internal landscaping. Two existing wetland areas at the northern end of the site will be preserved with a 25 foot buffer strip and a security fence. Erosion control practices during construction are proposed to minimize soil Impacts. Additional storm water run-off from plant expansion requiring treatment, would be treated on-site and discharged to Puget Sound via the Effluent Transfer System (ETS). The proposal and FSEIS discuss potential hazardous conditions from the Chlorine Building and Sulfur Dioxide area during construction and operations. Use and handling of these and other potentially hazardous chemicals and materials should be discussed in the Emergency Management Plan for the plant. e) Conservation of area-wide property values: The facility expansion, when fully implemented as proposed, will eventually enhance the visual appearance of the site, making the facility more visually compatible with adjacent office park development and thus, ensure area-wide property values. f) Safety and efficiency of vehicle and pedestrian circulation: No major off-site vehicular circulation modifications are proposed. Minor on-site circulation modifications are proposed to minimize existing conflicts adjacent to the existing administration building. Some vehicular and pedestrian conflicts could be expected to occur during the construction phase of the project. Temporary signage and signalization may be necessary during construction to minimize these conflicts. g) Provision of adequate light and air: Because many of the treatment processes on site require good aerobic interaction, the facility has been design for good air circulation both to reduce odors and enhance the treatment process. h) Mitigation of noise, odors and other harmful or unhealthy conditions: Noise levels are expected to Increase during construction. The distance to adjacent existing properties and the slight increase in noise over existing prelmrpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 8 background levels should make these Impacts minimal. Also, acoustical and odor reduction measures have been designed into the proposed facilities to meet established standards. 1) Availability of public services and facilities to accommodate the proposed use: As noted above, In Section D, Public Service, water and sewer are available at the site. Under the terms of the MOA, $2,500,000 would be made available by Metro for Improvements to enhance fire and emergency services. j) Prevention of neighborhood deterioration and blight: The subject site Is a large industrial complex. Substantial landscaping and berming is proposed to help the proposed expansion fit in with surrounding office- park and other industrial uses. In addition, as specified in the MOA, Metro has committed to fund the acquisition of wetland/wildlife habitat areas within 2500 feet of the site, which would contribute to neighborhood enhancement or maintenance. 6. CONSISTENCY WITH SHORELINE MASTER PROGRAM: This project requires a Substantial Development Permit under the City of Renton's Shoreline Master Program (adopted by Ordinance No. 3758). This section discusses the project's consistency with the Shoreline Master Program. A portion of the proposed plant enlargement involves approximately six acres of the site within the Shoreline Master Program area of the Springbrook Creek (Springbrook Creek). Springbrook Creek, within the City, is designated as a shoreline of state-wide significance. Proposed development within the shoreline area would Include: berming and landscaping, and construction of two of the four proposed Secondary Clarifiers (100 foot diameter), associated piping, a 375 foot extension of the existing Chlorine Contact Channel, minor roadway improvements, and a portion of the perimeter trail and fence around the plant. Under the Mitigation and Compensation section of the Memorandum Of Agreement (Section 4), Metro has agreed to fund up to $3,500,000 for the acquisition of riparian wetlands and uplands that could serve as habitat for wildlife within 2500 feet of the plant boundary, If It is legally entitled to proceed with construction on the site no later than mid- August 1991. These wetland/wildlife improvements shall be permanently dedicated to the public for the purposes of wildlife preservation and enhancement, Including use by the City for interpretive trail purposes. Such uses are encouraged under the City's SMP: "In this Master Program, priority is also given to planning for public visual and physical access to water in the Urban environment." The Springbrook Creek is designated as an Urban Environment under the City's Shoreline Master Program. The following discussion describes the proposal's consistency with applicable goals, policies and regulations contained in the Shoreline Master Program: a) General Goals and Policies: The proposed Expansion III is generally consistent with applicable goals and policies. The proposal is not a water-dependent activity with respect to the Springbrook Creek Shoreline. [Note: the plant was originally located here to discharge treated effluent into the Green River.] In fact, the proposal could not be a water-dependent use since the Soil Conservation Service owns Intervening property between the site and the Springbrook Creek. The proposed expansion, however, minimizes development within the 200 foot shoreline jurisdiction area. The proposal is not anticipated to create offensive or unsafe conditions. The proposal would enhance the shoreline area through development of perimeter landscaping. Proposed shoreline activities will not affect water quality, existing flow, or aquatic and wildlife habitat. Existing public access to the shoreline along the Springbrook Creek would not be affected by the proposal. The proposed "trail for guided tours" along the Springbrook Creek would be within the plant site boundary and perimeter security fence. Public access to the Springbrook Creek shoreline would prelmrpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 9 not be enhanced by this proposal unless the proposed Perimeter Trail were to be relocated outside the proposed security fence, or preferably onto SCS property. Staff,therefore, encourages Metro to work with the City and the Soil Conservation Service to explore the possibility of relocating the proposed trail to the east on SCS property to better provide public access to the Springbrook Creek shoreline. b) Urban Environment Goals and Policies: The Urban Environment is designated to accommodate high-intensity land uses, provide for water-dependent activities and encourage public access. The proposed expansion Is consistent with the first of these policies, in that the development would Intensify the established use within the existing site boundaries. The proposal would not be a water-dependent use because of the intervening SCS property. Public access to the Springbrook Creek shoreline would not be enhanced unless the proposed Perimeter Trail were to be relocated to outside the proposed security fence, preferably onto SCS property. c) General Use Regulations: Pollution and Ecological Disruption. The proposal should not adversely affect water quality or aquatic life along the Springbrook Creek. During construction, Metro proposes to use best management practices for erosion control. [See Attachment No. 1, Applicant's Narrative, p. 27 for erosion control plan.] Aquatic life may be influenced somewhat by construction activities, including landscaping and berming, however, impacts are considered to be temporary. Because of the distances involved, no impacts on the Heron Rookery are anticipated. Use Compatibility and Aesthetic Effects. Proposed facility construction within the shoreline area (Secondary Clarifiers) would be lidded and screened by perimeter landscaping. Proposed facilities would not obstruct views of the Springbrook Creek from adjacent properties or public streets east of the site. The facility's proposed perimeter berming and landscaping is designed to help existing and proposed development blend in better with adjacent developments. Public Access. A perimeter trail for"guided tours" on the landscaped berm along the Springbrook Creek is proposed. This proposal would do nothing to enhance public access along the shoreline of Springbrook Creek on adjacent SCS property. However, public access to the Springbrook Creek shoreline would be enhanced If the trail were relocated to the SCS property which directly abuts the shoreline. Facility Arrangement-Shoreline Orientation. Proposed treatment facilities would be located upland and Inland from the water's edge. These would be buffered from the shoreline by the existing and proposed perimeter landscaping (Phases A). Landscaping. The proposal includes extensive landscaping along the site perimeter as well as the interior, some of which is existing with the remainder to be Installed in Phases A and C. Unique and Fragile Areas. The proposal would not affect two existing wetlands on site, other than the construction of a security fence at the outside edge of a 25 foot buffer. In addition, under the terms of the MOA, Metro has agreed, for a period of up to one year after signing the MOA, to fund the acquisition of off-site wefland/wildlife areas. This acquisition would be dedicated to the public. d) Specific Use Regulations, Utilities: The proposal complies with the Specific Use regulations which call for landscaping and site screening of facilities. Architectural facades and treatment structures are designed to conform with structures on neighboring properties. pralmrpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 10 7. CONSISTENCY WITH SPECIAL PERMIT FOR GRADING: A grading permit for this type of facility is not typically required if the grading is associated with building construction. However, because of the areas and quantities of grading Involved, and because the building construction would not occur until Phase B, a Special Permit for grading is required. Section 4-10-3 defines procedures for Issuance of a Special Permit for Grading. To grant a special permit for grading, the Hearing Examiner shall make a determination that the activity would not be unreasonably detrimental to the surrounding area. The Hearing Examiner shall consider, but is not limited to,the following: a) Size and location of the activity. The project Involves excavation of approximately 260,000 cy. of excavation to allow construction of wastewater treatment tanks and other structures, and for construction of perimeter berms. About 100,000 cubic yards of the soil to be excavated for construction purposes will be used as the fill material for proposed perimeter landscaped berms (unless the soil proves to be contaminated). Remaining excavated soil will be stockpiled for backfill following facility construction and for the grading of proposed Internal landscaped areas. Preliminary soils analyses does not indicate the presence of contaminated soils. If encountered, contaminated soils would be transported and disposed off-site. Approximately 45,000 cy. of clean topsoil will be imported for landscaping. Approximately 35,000 cy. of clean structural backfill will also be imported to the site. There will be additional off-site disposal of construction debris, consisting of about 160,000 sf of pavement and 7700 If of curb and gutter. Construction of facilities will also require dewatering of portions of the site during Phase A, Site Preparation, and during Phase B, Facility Construction. Subject to testing for water quality, this groundwater will be used as recharge to maintain site hydrology. If contaminated water is encountered it will be treated and discharged to Puget Sound via the ETS. Metro is proposing to use City of Renton water for recharging under these conditions. City water capacity could be strained if these volumns were maintained for any calendar period of time. The applicant will need to discuss this proposal for the use of City water further with the City before it can be implemented. b) Traffic volume and patterns. Because of the large number of truck trips associated with the excavation and fill activities, Metro has agreed to prepare a Transportation Management Plan for City review, prior to the start of construction activities. As part of this plan, Metro will provide adequate Information to neighborhoods and businesses affected during construction; will schedule construction operations to minimize Impacts to peak hour traffic operations; and will prohibit construction worker parking on adjacent streets. Metro will also participate in the Grady Way Transportation Benefit Zone. The construction entrance will be off Monster Road SW. c) Screening, landscaping,fencing and setbacks. Excavation, fill and grading for facility construction will occur on the interior of the site and would be screened from adjacent office park development by the proposed perimeter landscaping and berm. Nevertheless, upland properties, such as on Earlington Hill, will still be able to see into the plant's Interior, albeit at great distances. The plant expansion will comply with setback requirements: 30 feet along Oakesdale Avenue SW, and 25 feet along Monster Road SW. d) Unsightliness, noise and dust. The proposed perimeter landscaping and berms will visually screen the facility during operations, as well as excavation and grading activities, during construction. Most noise levels from Oakesdale Avenue and the adjacent office park development to the east and the north, according to the EIS, are expected to Increase during construction, however, the distance to adjacent properties should make these impacts minimal. As noted above, acoustical and odor reduction measures are designed into the proposed facilities. Metro has agreed to employ prNmrpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 11 best management practices to control erosion and sedimentation, minimize fugitive dust generation, and to ensure that handling of dirt is not detrimental to the surrounding area. Measures would Include wetting exposed surfaces, and regular street cleaning. e) Surface drainage. Surface water quality would be maintained during construction under the erosion control plan for the project, which would be consistent with City of Renton requirements for erosion control and sedimentation. Metro will continually monitor sediment and surface water quality. Storm water runoff during project operation will be collected, and may be treated on-site and discharged consistent with NPDES and other applicable regulations such as the City's adoption of the King County Surface Water Drainage Design Manual. Excavation for proposed treatment facilities will extend below the level of groundwater,thus necessitating selective dewatering. The proposed groundwater dewatering system would utilize large diameter area wells. These wells would be operated In conjunction with recharge wells located near existing structures on- site to minimize potential settlement. Preliminary studies Indicate the need for dewatering rates of up to 5,000 gpm to control groundwater in deeper excavations. Should the groundwater prove contaminated, it would be treated on- site and discharged via the Effluent Transfer System. The applicant has proposed to use City water for recharging if this should occur. This must be coordinated with the City first. 8. CONSISTENCY WITH LAND CLEARING AND TREE CUTTING ORDINANCE (Routine Vegetation Maintenance Permit): Note: This permit is subject to administrative review and the analysis provided in this report is for informational purposes only. This chapter provides regulations for the clearing of land and the protection and preservation of trees and associated significant vegetation for the following (applicable) purposes: "L" To preserve and enhance wildlife and habitat including streams, riparian corridors, wetlands and groves of trees; and "M" To promote building and site planning practices that are consistent with the City's natural topographical and vegetational features while at the same time recognizing that certain factors such as condition (e.g., disease, danger of falling, etc.), proximity to existing and proposed structures and improvements, interference with utility services, protection of scenic views and the realization of a reasonable enjoyment of property may require removal of certain trees and ground cover. The following discusses the consistency of the proposal with Regulations for the Land Clearing and Tree Cutting and the Development of Property: a) Tree Cutting Plan. The applicant has submitted a land clearing and tree cutting plan. This plan has been reviewed as part of the SEPA review process by Metro. b) Conformance to Performance Standards Set Forth in Section 4-9-13. Proposed tree cutting is limited to areas of new facility construction. No cutting of protected native growth is involved. No cutting would occur within 25 feet of the two existing wetland areas. No cutting would occur within 25 feet of the annual high water mark or 15 feet of the top of the bank of the Springbrook Creek. c) Conditions. All land clearing and tree cutting activities shall be conditioned by the City to ensure that the following performance standards are met which: Protect potential land slide areas; Minimize potential erosion, flooding or water pollution; Preserve aesthetics; and Preserve habitat. The proposal complies with the performance standards. A condition, however, Is recommended requiring an erosion control plan prior to removal of any existing vegetation. prelmrpt PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 12 H. DEPARTMENTAL RECOMMENDATION: Staff recommend that the Hearing Examiner determine in favor of the proposed Site Plan Approval, Shoreline Substantial Development Permit, Special Permit for Grading for Metro's Wastewater Treatment Plant, Expansion III (File No. SA;SM;SP-040-91), subject to the following conditions: 1. Site Plan Approval: a) Mitigation Measures: Because of the Impacts Identified In the FEIS for the project, the applicant shall agree to implement all Mitigation measures, as ! .tA169 specified in Exhibit B of the attached Memorandum of Agreement [Attachment No. t-AbB �11% 41, and shall agree to Implement the MOA according to its terms and conditions �{( including the following: (1) Wetland Mitigation/Compensation. Because of potential impacts to existing on-site wetlands, and because the proposed use is not water- dependent, as required by the City's Shoreline Master Program, the applicant shall commit to fund up to $3,500,000 for the acquisition of riparian wetland and uplands that could serve as habitat for wildlife within 2500 feet of the plant boundary. These wetland/wildlife improvements shall be permanently dedicated to the public for the purposes of wildlife preservation and enhancement, including use by the City for Interpretive trail purposes. (2) Environmental Health/Public Safety Mitigation/Compensation. Because of potential Impacts of the project Identified in the EIS In the areas of Environmental Health and Public Safety, the applicant shall commit to fund $2,500,000 for public safety and community Improvements within the City of Renton to enhance fire and emergency response to the Wastewater Treatment Plant. (3) Conveyance System Impacts Mitigation. Because of potential impacts on the City of Renton's Sole Source Aquafer and other environmentally sensitive areas from the Wastewater Treatment Plant's sewage conveyance system, the applicant shall commit to design and construct several off-site sewage system improvement projects and associated local sewerage facility improvements related to the proposal. These shall Include: the Cedar River Trunk Relocation; the May Valley Interceptor Extension; and the Cascade Siphon/Footbridge. These projects will be subject to separate permitting and environmental review processes. Other system improvement projects may be added by mutually written agreement of the City and Metro. The estimated total cost of the system Improvement projects is $4,755,000 which will be borne solely by Metro. The City of Renton has agreed to reimburse Metro for design and construction costs associated with any local sewerage facility Improvements, after project completion in 1996. b) Additional Studies Required. Prior to the issuance of any permits for Phase B construction the applicant shall submit and obtain City staff review of the following studies: (1) Generalized Utilities Plans. These shall consist of preliminary plan drawings and calculations for the following utilities: Storm and Surface Water Drainage. This shall identify the location and preliminary size of storm and surface water control facilities needed to meet all of the applicable Core and Special Requirements contained in Chapter 1 of the King County Surface Water Design Manual, which the City of Renton has adopted. Storm and surface water facilities should be preliminarily sized and shown schematically on the site plan. The plan must address prelmrpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 13 methods for meeting water quality requirements for the Impervious areas subject to storage of chemicals or vehicular ,�p� use, prior to direct discharge to the Green River or ETS. 1"r�A J" Sewer. This shall consist of a report containing engineering L �1� calculations that demonstrates the City of Renton Wastewater Utility Department's requirement that surcharging of the ( y Interceptors and adjacent City collector sewers around the Metro N° �, Wastewater Treatment Plant will not exceed two feet below the rim of any manhole (approximately elevation 13) within either the 09 (� Metro or City of Renton systems. vow, Q Water. This shall identify fire flow requirements (see Item No. 2 below) and watermain extensions and improvements such as hydrants, fire sprinkler systems, backFlow preventers etc. Proposed improvements shall be shown schematically on the site plan. Plans shall show proposed improvements and utility relocations separately. (2) Fire and Emergency Management Plans/Special Operations Plan for Storage and Handling of Hazardous Materials. These plans shall address the following: Access. Primary and secondary access routes are to be maintained with prior approval of the City of Renton Fire Prevention Bureau Chief. Once established, these emergency access routes cannot be changed without Fire Prevention approval. Water. The applicant must coordinate all interruption of water supply serving hydrants and sprinkler systems with Fire Prevention. Fire Flow. The applicant shall provide sufficient information regarding building and facility construction to include: type of construction, total area in square feet, type of use including hazardous use of each building or facility. This analysis shall address the specific requirements regarding fire hydrants, fire suppression and alarm systems. 80 of the Uniform Fire Code. The applicant shall address TTy compliance with Article 80 of the Uniform Fire Code regarding all ;Article storage and dispensing of existing and proposed hazardous materials. All hazardous materials operations at the Metro � �xpot� Wastewater Treatment Plant must meet minimums specified in Py p� b,n rticle 80 UFC. ✓t' (3) Landscaping Plans. The applicant shall submit detailed landscaping p v development plans for the following: Detailed Landscape Plan for Phase C Internal Planting. This plan shall address proposed grading, plant materials and layout, and irrigation for the interior facility landscaping to be developed in Phase C. Detailed Landscape Plan for Additional Perimeter Landscaping in Phase C. This plan shall address the area along the site perimeter not Included in the Phase A planting plan. This Is the area along the Springbrook Creek between SW 7th Street and SW Grady Way. This plan shall Include proposed grading, plant materials/layout and Irrigation. Implementation of this plan should occur In Phase C, or as soon as possible after adjacent facilities (Chlorine Contact Channel extension) are completed. Note to applicant: The applicant is encouraged to either undertake joint development of a public access trail on SCS prelmrpt PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 14 property along the Springbrook Creek, or consider relocating the existing security fence to the upland side of the proposed trail, thus making it more accessible to the public. �0. (4) Roadway Improvement Plan. The applicant shall provide Roadway� R_ef_y'J� Improvement Plans for Monster Road SW and the Longacres Drive. 14, These shall run the full length of the property frontage. Plans shall �ft9 v include, but not limited to, curb, gutters, sidewalks, and street lighting. !!�r" (5) Traffic Signal Warrant Analysis. The applicant shall prepare a traffic signal warrant analysis for the Intersection of SW Grady Way and Longacres Drive. This intersection is presently at Level of Service E and should be upgraded to LOS D. (6) Transportation Management Plan. The applicant shall prepare a traffic control plan to be submitted to the City of Renton Transportation Division for construction activities. Proposed truck haul routes should also be coordinated with the City of Renton Police Department. Since Longacres Drive SW south of SW 16th Street is a private road, the plan should address arrangements for use of this street. This should be coordinated with the Boeing Co. (7) Hold Harmless. The applicant shall hold the City of Renton Harmless /r from any liability should any of the above studies (1-6) result in Increased project costs. It is also recommended that the applicant complete and submit these studies for City review, as soon as, possible in order to evaluate cost implications. g) Grady Way TBZ. The applicant shall participate In the Grady Way Transportation Benefit Zone pursuant to City Resolution No. 2827. This Is estimated to be $44,091 [213 increased vehicle trips x $207/trip), and should be paid at the time the building permit Is issued. �) Street Cleaning Bond. Prior to issuance of a building permit, Phase B, the '? applicant shall post a $5,000.00 bond with the City for street cleaning during construction. G � i) Roadway and Infrastructure Repair. Metro shall repair or pay the City of Renton rd for the repair of any damage to roadways or infrastructure resulting from construction, prior to the Issuance of the final occupancy permit. Detailed Erosion Control Plan. Prior to Issuance of the first permit for the project (Grading License), the applicant shall submit an erosion control plan for City staff review. This plan must be also be included in the applicant's construction contract for Phase A, Site Preparation. k) 2020 Plus Planning Participation. The applicant shall ensure City of Renton participation in all technical reviews of the Metro Wastewater 2020 Plus Study. Participation shall include the City of Renton Public Works Director and representatives from the Wastewater Utility Section, Long-Range Planning, Current Planning and the Mayor's Office. 7 yiR6 � 1) Security Procedures. Secyrtfy procedures should be established, in coordination with the City of Renton Police Department, for protection of the wastewater treatment plant, and particularly the outside storage of liquid chlorine and other hazardous materials. The applicant shall also notify Police and Fire in at least 24 hours In advance of any chlorine tank car movements, both inside and outside the wastewater treatment plant. PC "''r dy," �""e6-g� rW t�v ; e nrr70%W S..s I r arcs /�Y7 a qg . 2 • z J+wr tO n 2. Shoreline Master Program Substantial Development Permit: a) The same conditions as specified for No. 1, Site Plan Approval, shall apply to this permit. pmlmrpt PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 15 3. Special Permit for Grading: a) The same conditions as specified for No. 1, Site Plan Approval, shall apply to this permit. 4. Routine Vegetation Management Permit: a) The same conditions as specified for No. 1, Site Plan Approval, shall be administratively applied to this permit. 5. NOTE TO APPLICANT: The above conditions do not absolve the applicant from the responsibility of meeting all City codes, ordinances and regulations. p,.I.rpt FIND BA ( 5� 0 M E' T R �. , f \ W ' I ,5 P O E:.S .,A l L .. a ` I l �,' • , � A II '< Municipality of Metropolitan Seattle SA;SM;SP-040-91 APPLICANT Metro TOTAL AREA 94 S arrac PRINCIPAL ACCESS SW Grady Way Via Monster Road SW or Oakesdale Ave SW Via SW 7th 'St over P-1 Channel EXISTING ZONING P 1 Public Use EXISTING USE Metro Waste Water Treatment Plant PROPOSED USE F;etro Waste Water Treatment Plant, Expansion III COMPREHENSIVE LAND USE PLAN—Public/Quasi-Public COMMENTS Located @ 1200 Monster Road SW, Renton 1111 �,�,�ai—aI+a t:�n. ii:i '.•.•.•.:•:S q i4iil�i'ru•w • :: i.•Nn� on ..Me • nl. /� I gguu.• .0 y`,t,,Qi �i '.::�:•:�:�:�:•.?P+3i' L,,,(���yyy- 6::��+� f�'14 fin. . i:i .;.• sill n u nY ..r •. �1ap�.yp�t, sillY:::i \: N1l`D �Y' ... 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I PARKS AND RECREATION DIVISION OTHERS: REGARDINGCOMMENTS OR SUGGESTIONS APPLICATION KITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BY a 30 A.M. ON MAY 24,1991 REVIEWING DEPARTMENT/DIVISION: S7�ie/l/ 64422� _APPROVED _APPROVED WITH CONDITIONS NOT APPROVED �� �7n DATE: SJ NATURE OF D OR AUTHORIZED REPRESENTATIVE REV.5/90 dm hl •r :r. . ... . . . 1V1 L'. M Cl t( A 1V 'I7 U 1V1� DATE: May 24th, 1991 TO: Don Erickson Paul Forsander FROM: Randall Parsons/ SUBJECT: STORM WATER REVIEW OF REVISED SUBMISSION FOR METRO TREATMENT PLANT EXPANSION: APPLICATION NO.SA; SM; SP-040-91 As noted in my memorandum to you of March 12, 1990(enclosed for reference),the storm water management for this facility must comply with Chapter 4-22"Storm and Surface Water Drainage"of the City Code. In particular,it should be noted in Section 4-22-5"Submission of Drainage Plans Required:" (also enclosed for reference)that a drainage plan shall be submitted for approval for Site Plan Approvals. I have noted in my memorandum of March 11, 1991 to you that I feel that it is reasonable to consider such a drainage plan as conceptual (not full construction plans)but of sufficient detail on the Site Plan,and with preliminary calculations provided, to identify the location and preliminary size of storm and surface water control facilities needed to meet all of the applicable Core and Special Requirements contained in Chapter 1 of the King County Surface Water Design Manual which we have adopted. This is important in that surface water quantity and quality control facilities will normally have significant impacts on a project's site plan It is,therefore,particularly important that these facilities be preliminarily sized and shown schematically on the site plan proposed to be approved for this project,which they have not yet shown. In particular for this project will be the methods by which they will meet the water quality requirements for the impervious areas subject to storage of chemicals or vehicular use prior to direct discharge to the Green River. One option may be for them to collect runoff for up to the 2 year storm event (95% of the total runoff volume)and direct it for treatment in the Plant with storm water Rows in excess of this quantity directed to the outfalls to the River. Please give me a call at extension 5548 if you have any questions.regarding these comments. MANNINU to 1LUHNIUALSLHVIULS PARKS AND RECREATION DIVISION OTHERS: COMMENTS OR SUGGESTIONS REGARDING THIS APPLICATION SHOULD BE PROVIDED IN WRITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BY 8:30 A.M. ON MAY 24,1991 REVIEWING DEPARTMENT/DIVISION: payKs aY-cJ_ cYCaTloY1 _APPROVED _APPROVED WITH CONDITIONS NOT APPROVED DATE: 1IGNATURniDIFTECTOR OR AUTHORIZED REPRESENTATIVE REV. 5/90 asnvaM DATE: May 29, 1991 TO: Paul Forsander, Project Manager FROM: Sam Chastain, Parks & Recreation Director SUBJECT: Metro Waste Water Treatment Plant Expansion I have reviewed the proposal as submitted, and I have the following concerns: 1) I would recommend that the proponent explore the possibility of constructing a trail for pedestrians along the east property line adjacent to the SCS property along the P-1 Channel. If a trail is not feasible on the Metro property, I would recommend as part of the mitigation for recreation that the proponent negotiate an easement with SCS for a recreational easement and construct the recreational trail along the P-1 Channel. 2) 1 would recommend the 1%Arts Works proposal be incorporated as part of the trail system being proposed around the Metro plant boundaries. Also, I suggggest a security fence be placed in a fashion to accommodate the public wishing to use the trail system. I would not recommend a system where potential users check in at a security gate prior to using the trails. 3) I would recommend that detail landscaping plans be submitted prior to a grading permit being issued. I would also recommend additional landscaping be provided along the Metro property along Oakesdale and the P-1 Channel. SC:wr mLrmxp POL IGL UkF'ARTMENT DEVELOPMENT SERVICES DIVISION CONSTRUCTION FIELD SERVICES DEVELOPMENT PLANNING PLANNING&TECHNICAL SERVICES PARKS AND RECREATION DIVISION —OTHERS: COMMENTS OR SUGGESTIONS REGARDING THIS APPLICATION SHOULD BE PROVIDED IN WRITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BY 8:30 A.M. ON MAY 24,1991 REVIEWING DEPARTMENT/DIVISION: PO 1 ('e z w APPROVED APPROVED WITH CONDITIONS NOT APPROVED ge,�.ii�L�l�v-� �1Uced,i.vle� b'��uu.« bey P�1-aV����b�enL. 1Z� 1lo LLUA 1_1�1rnv 1 n l�,Lll�v �j Gl tticl� DATE: 6SZ�c�i SIGNATURE OF DIRECTOR OR AUTHORIZED REPRESENTATIVE REV.5/90 d. hl DATE: May 28, 1991 TO: Paul Forsander, Project Manager FROM: Penny Bryant,Police Department SUBJECT: METRO REGIONAL TREATMENT PLANT- ENLARGEMENT III The police department is concerned about the traffic that is proposed to be generated by the treatment plant expansion. Once the plant is complete,the traffic increase is relatively small. The greatest concern however,is during the construction phases when it appears that there will be in excess of 400 vehicle trips per day. The city frequently requires advanced approval of "haul routes." This seems like a reasonable requirement considering the volume of trips expected with this expansion. The police department has is the past received numerous odor complaints,especially during the summer months. However, the application narrative indicates that the tank covers will be "fixed" to improve odor release. The metro site is a secured site. However, there is concern about the possible access to the chlorine facilities that pose a grat health threat. Accordingly,we would like to know what security measures are taken surrounding the storage and access to the chlorine facilities. DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS DEVELOPMENT APPLICATION REVIEW SHEET APPLICATION NO(S).: SA;SM;SP-040-91 PROPONENT: Municipality of Metropolitan Seattle (METRO) PROJECT TITLE: Metro Plant Expansion, III BRIEF DESCRIPTION OF PROJECT: Three phase expansion of Metro Treatment Plant at Renton: One: Site Preparation (excavation, fill and grading) and Perimeter Landscaping; Two: Facility Construction;Three: Interior Landscaping and Site Clean-up.. LOCATION: SEC: 24 TWNSHP: 23N RNG: 4E 1200 Monster Rd SW, Renton TO: PUBLIC WORKS DIVISION SCHEDULED TAC DATE: 5/24/91 ENGINEERING SECTION TRAFFIC ENG. SECTION UTILITIES ENG. SECTION FIRE PREVENTION BUREAU POLICE DEPARTMENT DEVELOPMENT SERVICES DIVISION CONSTRUCTION FIELD SERVICES DEVELOPMENT PLANNING PLANNING &TECHNICAL SERVICES PARKS AND RECREATION DIVISION _OTHERS: COMMENTS OR SUGGESTIONS REGARDING THIS APPLICATION SHOULD BE PROVIDED IN WRITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BY 8:30 A.M. ON MAY 24,1991 REVIEWING DEPARTMENT/DIVISION: � � ��'�/�G APPROVED APPROVED WITH CONDITIONS NOT APPROVED DATE: SIGNAT RE OF DIRECTOR OR AUTHORIZED REPRESENTATIVE REV. 5/90 dervshl TO: iecluucalNuvib�6y �ouuum�e FROM: Paul Forsander, Project Manager SUBJECT: METRO WASTE WATER TREATMENT PLANT-Expansion III - Proposed Site Plan Approval Conditions. Application No.SA;SM;SP-040-91 The Metro Waste Water Treatment Plant Expansion III Is scheduled for Hearing Examiner Site Plan Review on June 11, 1991. As you are aware It is Incumbent upon the City under the terms of the Memorandum of Agreement to "make best efforts" to facilitate permit review and approval by that date. Failure to do so would mean loss of the $6 million specified for compensation by Metro under the M.O.A.. Concern has been expressed by several of the reviewing departments over the adequacy of Metro's submittal in areas of: transportation, utilities and landscaping. After reviewing the Site Plan Approval Ordinance, I believe we can recommend Site Plan Approval by the Hearing Examiner and still satisfy the concerns of the reviewing departments. Authority for Hearing Examiner Approval. Section 4-31-33 provides for Hearing Examiner Approval If the proposed Site Plan Is consistent with the general purposes of the Section and review criteria. The Section also allows the Hearing Examiner to place reasonable conditions on, or modify, a site plan In order to satisfy the general purposes of the Section or achieve consistency with the site plan criteria. Recommendations for Site Plan Approval. I believe the Metro Waste Water Treatment Plant Site Plan for Expansion III meets the general purposes of Section 4-31-33 and satisfies most of the review criteria except In areas such as: utilities, transportation /streets and landscaping. I also believe that the plans and Improvements required for each of these areas would not materially change the overall site plan concept or its Impacts. Therefore, I propose that we recommend that the Hearing Examiner Approve the Site Plan with the following conditions: 1. Phasing: As proposed, the Project would be accomplished in three phases: Phase "A" (1991/1993) Includes Site Preparation (excavation, fill and grading) and Perimeter Landscaping (except for the area along P-1 Channel between Grady W. and SW 7th); Phase "B" (1993/1995) Includes building and treatment facility construction; Phase "C" (1996) Includes construction clean-up and Internal landscaping. Conditions should be placed on project phasing to require additional project design and construction to make the Site Plan consistent the general purpose and criteria of Section 4-31-33. These conditions are specified in items 2 and 3 following: 2. Facility Planning and Design. Prior to the Issuance of any permits for Phase A (approximately Issuance date of permits for Grading. Landscaping and Routine Vegetation Maintenance is Mid-August 1991), Metro shall submit and obtain City Staff Review of the following planning and design studies: a. Detailed Landscape Plan for Phase C Internal Planting. This shall Include proposed grading, plant materiais/layout and irrigation. b. Detailed Landscape Plan for Phases B&C This shall address Perimeter Landscaping along the P-1 Channel for the area between SW 7th Street and SW Grady Way. c. Potential Joint Development Plan for SCS Property Along P-1 Channel. This plan shall address potential joint development for landscaping and a public trail on SCS property along the P-1 Channel abutting the Metro site.. d. Generalized Utilities Plans. These shall address compliance with City Code requirements for: water/fire flow, sewer, storm water drainage, and erosion control. e. Transportation/Street Improvement Plan. These plans shall address any Code required Improvements for street paving, curbs and gutters, sidewalks, planting and street lighting. Plans shall also address traffic Improvements such as signalizatlon. f. Emergency Access Management Plan. This plan shall address fire and emergency access requirements during construction. 3. Facility Construction. Metro shall formally commit to Implement the requirements and Improvements Identified in the planning and design studies described In Item 2 ,above, as part of the following project Phases: Phase A Metro shall submit and obtain City Review of all planning and design studies specified in Rem 2, above, prior to Issuance of the Phase A Building/Grading permit (approx. Mid Aug '91). Metro shall complete all Code required off-site/public right-of-way utility and infrastructure Improvements by the end of this phase. Phase B Metro shall complete the remaining Perimeter Landscaping not Implemented In Phase A along the P-1 Channel property line as soon as possible during this phase (after the construction of the Chlorine Contact Channel Extension Is completed). Metro shall also pursue joint development on SCS property along the P-1 Channel during this Phase. Metro shall also complete all Code required on-site utility and transportation improvements by the end this phase. Phase C Metro shall complete the internal landscaping by the end of this phase. AM DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS DEVELOPMENT APPLICATION REVIEW SHEET APPLICATION NO(S).: SA;SM;SP-040-91 PROPONENT: Municipality of Metropolitan Seattle (METRO) PROJECTTITLE: Metro Plant Expansion, III BRIEF DESCRIPTION OF PROJECT: Three phase expansion of Metro Treatment Plant at Renton: One: Site Preparation (excavation, fill and grading) and Perimeter Landscaping; Two: Facility Construction;Three: Interior Landscaping and Site Clean-up.. LOCATION: SEC: 24 TWNSHP: 23N RNG: 4E 1200 Monster Rd SW, Renton TO: PUBLIC WORKS DIVISION SCHEDULED TAG DATE: 5/24/91 ENGINEERING SECTION TRAFFIC ENG. SECTION UTILITIES ENG. SECTION FIRE PREVENTION BUREAU POLICE DEPARTMENT DEVELOPMENT SERVICES DIVISION CONSTRUCTION FIELD SERVICES DEVELOPMENT PLANNING PLANNING &TECHNICAL SERVICES PARKS AND RECREATION DIVISION OTHERS: COMMENTS OR SUGGESTIONS REGARDING THIS APPLICATION SHOULD BE PROVIDED IN WRITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BY 8:30 A.M. ON MAY 24,1991 REVIEWING DEPARTMENT/DIVISION: �/ cY 4 nL Y I ZC l f t /c ✓ e L�)�C ���nl��`"S APPROVED _APPROVED WITH CONDITIONS �) /�OT APPROVED Ne, C�Y-.�W r Yl_� -� C��" Ct wiMH�+�l1X• I � i DATE: SIGNATURE OF DIRECTOR OR AUTHORIZED REPRESENTATIVE REV.5/90 d.v hl Review Comments Transportation - Development Services Metro Plant Expansion, SA;SM: SP-040-91 May 24, 1991 1. Participation in the Grady Way Transportation Benefit Zone Mitigations required. 213 (estimated increased vehicle trips) x $207 = $44, 091. 00 This should be paid at time building permit is issued. 2 . Roadway improvement plans to be provided for Monster Road and for Longacres Drive for the full length of the property frontage. Item included, but not limited to, curb, gutters and sidewalks. 3 . Street lighting plans and provisions to be provided on Longacres Drive and on Monster Road the full length of the property where it abuts the roadway. sw 1"N Wa 4 . The intersection of 46 - , � and Longacres Drive is apparently at a service level E. A traffic signal warrant analysis is to be provided. Also, design recommendations for the intersection is to be provided to return the service level back to a D level. 5 . A traffic control plan to be submitted to the City's Transportation Division for construction' activities. 6. With the amount of hauling, the developer should be committed to a significant bond for street cleaning. Recommended minimum bond for this purpose is $5, 000. 00. 7. Items to be addressed, as stated in Mel Wilson's Memorandum to Don Erickson on April 19 , 1991. a. Roadway infrastructures resulting from increased truck traffic to be addressed by Metro. An additional mitigation fee for future repairs should be agreed upon. b. Longacres Drive S.W. and S.W. 16th Street is a private road. What arrangements does Metro have which allows them to currently use this road? Will this roadway be available for Metro's use in the future, in light of Boeing's proposed development at the Longacres site? C. Construction operation should be scheduled to minimize impact during peak traffic times. ( 1.) Flagmen may be required at non-signalized intersections (Longacres Drive SW & SW Grady Way in particular) . ( 2 .) The contractor is to coordinate construction routes with the City's Transportation office. d. Metro must repair or pay for the repair of any damage to the roadway, infrastructures resulting from construction. DEVELOPMENT SERVICES DIVISION CONSTRUCTION FIELD SERVICES DEVELOPMENT PLANNING PLANNING &TECHNICAL SERVICES PARKS AND RECREATION DIVISION —OTHERS: COMMENTS OR SUGGESTIONS REGARDING THIS APPLICATION SHOULD BE PROVIDED IN WRITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BY 8:30 A.M. ON MAY 2401991 REVIEWING DEPARTMENT/DIVISION: APPROVED _ C�APPROVED WITH CONDITIONS NOT APPROVED L)e4Uc9-� I L Vla Z_�, SPY fL,ALL61vvrzov o i— Mt—iTt�-'o 64� ta' bvtye� A l Fbc DPP 1{!�S ��y �llMfT9EG2Jl tZEJtitT_ 41A� SJrzGl6�lkizlrlC� r-a ejL_j 7 y �l-1 w 1-61- F_C— YiTG(-oLo Aa-1 � UIIoL� uJ(TU-ml- ryt�lzo'� (� /V DATE: SIGNATURE OF DIRECTOR OR AUTHORIZED REPRESENTATIVE REV. 5/90 d.�hi REVIEWING DEPARTMENT/DIVISION: WWWA/ LM'U4`( APPROVED APPROVED WITH CONDITIONS x NOT APPROVED IUMLiuL"M)A FAfenji C (ilia 3E 2eC,(i((t-0 TD (7eGl7ioE Aof&uA-fE fine pparc aj TD PQa00SF0 lvwlywTsI fine -SP2iulc'eA, sYisb4s ) i F Affti(A V& U3111. U&)11E .St fi16 _% PARAiE uTialiCS 'INPjt4tXm ;N% PIAuL -1 IATi -NO, Su6srx -co ML A9iUCANCr 1EaMR F-Es AT rinE or Dft)Cv6rHcNT PftauJ' 6kk0611V _ Wkiln UfiUPI DATE: MA'( 2q. 1+11 SIGNATURE OF DIRECTOR OR AUTHORIZED REPRESENTATIVE REV. 5/90 devmhl utVtuir'vi"Nl SERVICES DIVISYuty CONSTRUCTION FIELD SERVICES DEVELOPMENT PLANNING PLANNING &TECHNICAL SERVICES _PARKS AND RECREATION DIVISION OTHERS: COMMENTS OR SUGGESTIONS REGARDING THIS APPLICATION SHOULD BE PROVIDED IN WRITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BY 8:30 A.M. ON MAY 24,1991 REVIEWING DEPARTMENT/DIVISION: APPROVED _ZAPPROVED WITH CONDITIONS NOT APPROVED (X DATE: / NATUR OF DIRECTOR OR AUTHORIZED REPRESENTATIVE REV. 5/90 damn' REVIEWING DEPARTMENT/DIVISION: cnndyuAon I�ph APPROVED APPROVED WITH CONDITIONS NOT APPROVED �uL�9m-i-cb vo ' y �- DATE: SIGNATURE OF DIRECTOR OR AUTHORIZED REPRESENTATIVE REV. 5/90 deg ht �o� C omxrAr nw-..1a Ix 04ANI IIfI. �'i � TY WA �l dmrtreK rxwM1 < _ ` I t rl arwo+r <A Y r •• / s' � Av�`aw u�.amxm wxlwo wx I xsma xm D1 m ATMrT FxO ixxp1W mETA0 E¢EFTA' mural v�auncs 1, IICwI PC DAM' MAY zo.101 �.�.. A mil p -s�ail ,: � oo I , i4 yy b 11 .y l tfiMi noy¢!i mxxus] 40 yi �MEPN�/r nuW uN2a T tl. 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Rmnw swx .r�`w�.ewpmr"w srwnnrxs fwe acwo.nr Piw vnsna xf.fwunr srwi uw.nm. --rx rwrnr�.Ruu,wi runs.san �� nn.rt snnna rux ��a —enoc s,w.¢run SJ —mw nP.cnw mu qv a¢zrm awa nUnxc rr.,w, N1[u BPn Y_qF i,s ren Y 2 P�mR i4 r4 mwa a:wnmc Pec u�w.uim v'i= —F wnAYu[ Y 0 1 1 Pgy 3 • ^ rc l a � ,wu N •5 €� i !' • ` a ww 1 W + — j Q /�j�, j ! /,: %! e / ��/� j f i r�s..x�+e..✓w.a.T evnw.�yw+iey i '* f�. . � / pGMSN i'LawY.WaPER.KiER ,K ` '.• // 1 Y- . / .� . 1. \ . — .u.nur srt ort.wnc 61v ��ff :aRIETRO ................... BYBrown and Caldwa0 .rs.��� I ..:... .K.w..;.,.. ,. Consultants PLANTING PLAN ta: AREA 24 / . � mW,- Y ! ,M Y •� / ' �``� T / / T + O fu ka P-0- Rw ;� �' pg. - mac_ ` 1 •' � _ I i toJ.. c .*cn uxc 4i q+.e. �Ni4 I W Brown rW Cawd JU p ai Consu fant5 PLAN TING'PLAN i 1418 i�•i �I ! AREA 26 _4T 0/ 171 DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS DEVELOPMENT APPLICATION REVIEW SHEET APPLICATION NO(S).: SA;SM;SP-040-91 PROPONENT: Municipality of Metropolitan Seattle (METRO) PROJECT TITLE: Metro Plant Expansion, III BRIEF DESCRIPTION OF PROJECT: Three phase expansion of Metro Treatment Plant at Renton: One: Site Preparation (excavation, fill and grading) and Perimeter Landscaping; Two: Facility Construction; Three: Interior Landscaping and Site Clean-up.. LOCATION: SEC: 24 TWNSHP: 23N RNG: 4E 1200 Monster Rd SW, Renton TO: PUBLIC WORKS DIVISION SCHEDULED TAC DATE: 5/24/91 ENGINEERING SECTION TRAFFIC ENG. SECTION - — UTILITIES ENG. SECTION 51Tci?i"1 Wl' 7GA2 I/ �t7el/� FIRE PREVENTION BUREAU / POLICE DEPARTMENT DEVELOPMENT SERVICES DIVISION CONSTRUCTION FIELD SERVICES DEVELOPMENT PLANNING PLANNING &TECHNICAL SERVICES PARKS AND RECREATION DIVISION OTHERS: COMMENTS OR SUGGESTIONS REGARDING THIS APPLICATION SHOULD BE PROVIDED IN WRITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BY 8:30 A.M. ON JUNE 7,1991 REVIEWING DEPARTMENT/DIVISION: -5 WA L—y n� l/774-1Ty S 117 � J�/✓/S/� _APPROVED APPROVED WITH CONDITIONS NOT APPROVED r /4'0'aLlceNT sf7ew /L���T 0�� lam^'✓/ 77 vlo 7w�2 p e4/, ,, Gcg_ ��i`!/^'� r /`2�.0 �l/i4i7�si✓a %��Tr`>�1� �/�.o N7� �,CPA�o �- DATE: / )SIGTURE OF DIR �IZ;DEPRESENTATIVE REV. 5/90 de hl i CITY OF RENTON MEMORANDUM DATE: June 5, 1991 b f TO: Reviewing Departments: Randall P s, Storm Water Utility; Clint Morgan, Transportation; Abdoul Gafour Wate Utility; Sam Chastain;Parks;and, Mary Lynne Myer, Long Range Planning. FRO Don Erickson, Zoning Administrator Paul Forsander, Staff Contact 6167 SUBJECT: Metro Waste Water Treatment Plant, Expansion III SA;SM;SP-M-91. REVISED REVIEW COMMENTS The Metro Project is scheduled for Public Hearing on June 11, 1991, It is of utmost importance to the City, that this project receive timely and complete review in order to fulfill our obligations under the Memorandum of Agreement. The MOA was approved by the City Council on Monday, June 3, 1991. Several departmental reviewers recommended denial, while at the same time made comments on conditions for approval. Your comments have been incorporated into the attached Preliminary Report to the Hearing Examiner. Please review the report and the conditions contained in the Departmental Recommendation (pp. 12-15). Based upon the revisions presented herein, I would like you to reconsider your review of the project. If you have any questions concerning this matter please contact Paul Forsander at 6167. Thank you for your cooperation. r DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS PRELIMINARY REPORT TO THE HEARING EXAMINER PUBLIC HEARING APPLICANT: Municipality of Metropolitan Seattle (Metro) PROJECT NAME: Metro Wastewater Treatment Plant, Expansion III FILE NUMBER: SA;SM;SP-M-91 LOCATION: SEC: 24; TWMSHP: 23N; RNG: 4E 1200 Monster Rd SW, Renton A. SUMMARY AND PURPOSE OF REQUEST: The applicant (Metro) seeks to obtain: a) Site Plan Approval and Shoreline Master Program Substantial Development Permit to expand facilities at the existing Metro Wastewater Treatment Plant, thus increasing secondary treatment capacity from 72 million gallons per day (mgd) to 108 mgd; b) Special Permit for Grading (Excavation, Fill and Grading); and c) Routine Vegetation Management Permit [Note: the Routine Vegetation Management Permit is subject to administrative review and approval, and is included In this report for Informational purposes] to allow preparation of the site for construction prior to Issuance of a building permit. The proposed expansion would occur in three phases: Phase A (1991-1993): Site Preparation (vegetation clearing, excavation, fill, grading and site dewatering) and Perimeter Landscaping; Phase B (1993-1996): Facility Construction; and Phase C (1996): Interior Landscaping and Site Clean-Up. B. GENERAL INFORMATION: 1. Owner of Record: Municipality of Metropolitan Seattle (Metro) 2. Applicant: Municipality of Metropolitan Seattle (Metro)/Gerrie Jackson 3. Existing Zoning: P-1, Public Use 4. Existing Zoning in the Area: City of Renton Zoning: B-1, Business Use; M-P, Manufacturing Park; L-1, Light Industry; O-P, Office Park; P-1, Public Use; City of Tukwila Zoning: RA, Agricultural; C-2, Regional Retail; M-1, Light Industry. 5. Comprehensive Land Use Plan: Public/Quasi-Public 6. Size of Property: 84.5 Acres 7. Access: SW Grady Way Via Monster Road SW or Oaksdale Ave SW Via SW 7th St Bridge over Springbrook Creek. 8. Land Use: Metro Wastewater Treatment Plant 9. Neighborhood Characteristics: North: Undeveloped (Proposed Office Park) East: Office Park and Springbrook Creek South: Industrial and 1-405 I West: Industrial and Black River Channel prelmrpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 2 C. HISTORICAL/BACKGROUND: Action File Ordinance Date Annexation 1745 4-14-59 Amend. Ord. 1764 5-27-59 Amend. Ord. 1928 12-22-61 Special Permit SP-065-81 Special Permit SP-006-83 Conditional Use CU-007-83 Substantial Shoreline SM-107-83 Variance V-045-84 Conditional Use CU-087-84 Variance V-088-84 Substantial Shoreline SM-118-84 Rezone R-046-85 3961 12-13-86 Shoreline Exemption SME-003-85 Site Plan Approval SA-061-87 Special Permit SP-062-87 D. PUBLIC SERVICES: 1. Utilities a. Water: A number of private (Metro) 12-inch water lines serve the site. These mains interconnect with the City of Renton Water System. b. Sewer: A 12-inch sanitary sewer serves the site perimeter (see attached map). There are a number of Metro-owned sewers on-site. C. Storm Water Drainage: Existing storm water runoff from Impervious surfaces is collected and discharged to the Green River. Future runoff from the proposed expansion will also be collected, treated on-site and discharged consistent with National Pollutant Discharge Elimination System (NPDES) permit requirements and other applicable regulations, such as the City of Renton's adoption of the King County Surface Water Design Manual. 2. Fire Protection: Provided by the City of Renton as per ordinance requirements. 3. Transit: Not Applicable 4. Schools: a. Elementary Schools: Not Applicable. b. Middle Schools: Not Applicable. C. High Schools: Not Applicable. 5. Recreation: City of Renton Parks: Earlington Park is 0.80 miles north of the site; Lake Street Park is one mile southeast of the site; and Oakesdale Park (Springbrook Creek) is immediately adjacent to the site. City of Tukwila Parks: Fort Dent Park is approximately 500 feet west of the site; Foster Golf Course lies northwest of Fort Dent Park, approximately 0.75 mile from the site. E. APPLICABLE SECTIONS OF THE ZONING CODE: 1. Section 4-31-9, Public Zone (P-1). 2. Section 4-31-33, Site Plan Review. 3. Section4-31-34, Landscaping. prelm rpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 3 4. Section 4-31-27, Mining, Excavating and Grading. 5. Section 4-9, Land Clearing and Tree Cutting Ordinance. F. APPLICABLE SECTIONS OF THE COMPREHENSIVE PLAN OR OTHER OFFICIAL CITY DOCUMENT: 1. Valley Planning Area, City of Renton Comprehensive Plan. 2. Policies Element, VIII -Utilities Goal, D. Sanitary Sewers Objective, City of Renton Comprehensive Plan Compendium, 1986, pp 22-23. 3. Policies Element, III -Urban Design Goal, C. Landscape Objective City of Renton Comprehensive Plan Compendium, 1986, pp. 10-11. 4. Shoreline Master Program, City of Renton, Adopted by Ordinance No. 3758. 5. Grady Way Transportation Benefit Zone, Adopted by City Resolution No. 2827. G. DEPARTMENT ANALYSIS: 1. BACKGROUND The applicant is seeking Site Plan Approval, a Shoreline Substantial Development Permit, a Special Permit for Grading, and a Routine Vegetation Management Permit [Note: the Routine Vegetation Management Permit is subject to administrative review and approval, and Is included In this report for informational purposes only) to allow construction for expansion of the existing Metro Wastewater Treatment Plant located at 1200 Monster Road SW. The existing regional wastewater treatment facility presently handles 72 mgd under average wet weather flow. The proposed expansion would increase the total capacity to 108 mgd (average wet weather flow). While the plant capacity of 108 mgd would be completed in 1996, it is estimated that capacity would not be reached by the Metro system until approximately 2005. The proposed expansion would occur in three phases: Phase A (1991-1993)would consist of Site Preparation (Excavation, Fill, Grading and De-Watering) and Perimeter Landscaping; Phase B (1993-1995) would consist of Facility Construction; and Phase C (1996) would consist of Site Clean-Up and Internal Landscaping. [Please see Attachment No. 1 for applicant's narrative containing detailed project description.] Metro evaluated four treatment facility layout alternatives for the Renton Facility in its recent Supplemental EIS for the proposed expansion (see No. 2 below for discussion of EIS). Alternative 2 was selected as the preferred alternative. This alternative increases plant capacity by upgrading and enhancing the existing treatment facilities and by constructing additional tank structures and other facilities totalling approximately 165,000 sf. Proposed new structures would include: Four (4) Primary Sedimentation Basins; One (1) Four-Pass Aeration Basin; Four (4) Secondary Clarifiers and Associated Channels; Two (2) Dissolved Air Flotation Thickeners with Odor Reduction Tower; One (1) Digested Sludge Blending Tank; and One (1) Waste Gas Burner. Channels and pipelines necessary to convey various process streams to and from process units will also be constructed. All proposed construction would occur within the site boundaries of the existing wastewater treatment plant. The existing plant was constructed by Metro in three stages: 1) The original plant was constructed in 1965 with a capacity of 24 mgd; 2) the first expansion was completed in 1974 (Note: the first expansion was approved as part of the original plant permit) Increasing the plant capacity to 36 mgd; and 3) the second expansion was completed In 1988 (Note: approvals for the second expansion occurred between 1983 and 1987), which Increased the plant capacity to its present 72 mgd, and also completed the Effluent Transfer System (ETS) to Elliott Bay. With the completion of the ETS pipeline, effluent discharge was discontinued to the Green River and final effluent was discharged to the marine waters of Puget Sound. This proposal will be the third expansion of the plant, hence it is named Metro WasteWater Treatment Plant, Expansion III. The existing plant layout and site plan have the capacity to accommodate additional future expansions to achieve an ultimate capacity of approximately 250 mgd. The need for future plant expansions will be addressed in Metro's "WasteWater 2020 Plus" study which is scheduled pmlmrpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 4 for completion In the mid-1990's. The 2020 study will determine if additional enlargements of the regional treatment plant at Renton are required or whether increased flows should be accommodated by other means, such as new treatment plants or service area changes within the Metro service area. Approximately 6 acres of the plant site lie within Renton's Shoreline Management district, which extends 200 feet westward from the line of the high water mark in Springbrook Creek/P-1 Channel. Work within the shoreline area relates to berming and landscaping, construction of two of the Secondary Clarifiers, extension of the Chlorine Contact Channel, minor roadway Improvements, and development of a perimeter trail (for guided tours) adjacent to the existing and security fence along the Springbrook Creek. This trail would not be accessible to the public without checking in at the Administration Building and an escort from Metro. Soil excavation for facility construction will involve approximately 260,000 cubic yards. About 100,000 cubic yards of this soil will be used for fill material for proposed perimeter landscaped berms, unless the soil proves to be contaminated. In addition, approximately 45,000 cy. of clean topsoil will be imported for landscaping. Remaining excavated soil will be stockpiled for backfill following facility construction and for grading for proposed Internal landscaped areas. Preliminary soils analyses does not indicate the presence of contaminated soils. If encountered, contaminated soils would be transported and disposed of off-site. Approximately 35,000 cy. of clean structural backfill will also be imported to the site. There will be additional off-site disposal of construction debris, consisting of about 160,000 sf of pavement and 7700 If of curb and gutter. Construction of facilities will also require dewatering of portions of the site, particularly during Phase A, Site Preparation. Excavation for proposed treatment facilities will extend below the level of groundwater, thus necessitating selective dewatering. The proposed groundwater dewatering system would utilize large diameter area wells. These wells would be operated in conjunction with recharge wells located near existing structures on- site to minimize potential settlement. Preliminary studies indicate the need for dewatering rates of up to 5,000 gpm to control groundwater in deeper excavations. Should the groundwater prove contaminated, it would be treated on-site and discharged via the Effluent Transfer System (ETS). There will be minimal road circulation and parking Improvements on-site. The two access roads on the west side of the site, and the road along the administration building will be replaced with one access road. Roads adjacent to the Sludge Dewatering Building will be reconstructed for increased radii for truck turning and reduced slope for better winter Ice conditions. The turning radii of several roads on-site will be revised to accommodate wide turning trucks. Approximately 35 additional parking spaces will be constructed along the existing Chlorine Contact Channel. Significant landscaping is proposed for the site to provide visual buffering along the Springbrook Creek and to breakup large open internal areas that are not scheduled for development in this expansion. The landscaping and site plan layout is designed to eventually create a campus-like appearance and to relate to neighboring office park development. It will probably take five years for the landscaping to reach maturity, thus the planned effect should be in place by 1996 for the Perimeter Landscaping and 2000 for the Interior Landscaping. Perimeter berms and landscaping are proposed for construction during Phase A. Internal landscaping is proposed in Phase C. Metro is proposing that the Internal Landscaping be considered as "temporary" and would be subject to removal to allow for future facility construction to meet future needs identified in the 2020 Plus study, and, subsequently, approved by the City. There are two small wetland areas, of approximately 2 acres, at the northern most portion of the site, which will not be affected by this proposal. These wetland areas will be protected during construction and project operation by a fence and a 25 foot wide buffer strip. 2. ENVIRONMENTAL ANALYSIS Metro, as lead agency for the proposed action, prepared an EIS for the project. [See Attachment No. 2] The EIS was a Supplemental EIS which supplements the environmental reviews for wastewater treatment plant expansion which were completed in 1981 and 1986 by Metro. The Supplemental EIS is a project-level EIS for expanding Metro's facilities at prelmrpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 5 Renton to treat up to 108 mgd. According to Metro, the EIS was used to select a final layout for Implementing the expansion of the wastewater treatment plant, and to support application for project permits. Metro Invited public participation during the planning and environmental review process. Metro conducted several public scoping meetings during January and February, 1991. A Determination of Significance (DS) and scoping notice announcing its Intent to prepare a Supplemental EIS on the project was Issued by Metro on January 11, 1991. Approximately 500 scoping notices were distributed during a comment period of four weeks. The draft supplemental EIS was Issued on March 22, 1991, with the public comment period extending through April 22, 1991. Metro held two informational public meetings, followed by formal public hearings In the Renton City Council Chambers to receive comments on the draft EIS. Approximately eight citizens attended the first public hearing and asked questions during the Informal presentation about the project. No one commented during the formal public hearing. A second public hearing was held with four citizens attending. Only one person commented during the formal public hearing. That person spoke In favor of the project. Metro's environmental compliance division received a total of seven comment letters on the DSEIS: four letters from agencies,two letters from citizen groups, and one letter from a neighboring business. Comments primarily focused on the issues of aesthetics, noise, traffic, odor and potential Impacts to the great blue herons. The City of Renton had extensive comments on the DSEIS. [See Attachment No.3 for City of Renton Comments.] The Final Supplemental EIS was Issued on May 24, 1991. The Final EIS was revised in response to written comments received during the public comment period. Mitigation was proposed In the FSEIS In response to City of Renton and other comments. Based on the FSEIS, Metro has committed to implement specific mitigating measures. These are contained in Exhibit B of the "Memorandum of Agreement between Metro and the City of Renton. [See Item 3 below for discussion of Memorandum of Agreement.] Differences between the FSEIS and the Proposal. Because of budget limitations, the expansion contained in this proposal has been scaled down from Alternative Two described in the FSEIS: Only four (4) of the eight (8) Secondary Clarifiers would be constructed, and there would be no anaerobic digester constructed. The remaining facilities,will be reviewed as a separate application after 1996. 3. MEMORANDUM OF AGREEMENT The Memorandum of Agreement (MOA) between Metro and the City of Renton was created to resolve Metro's objective to begin construction of the proposed expansion in mid-August 1991 and address the City's concern over potential environmental impacts, particularly in areas of wetlands and environmental health. To that end, Metro and the City of Renton have entered Into an agreement which formally defines mitigation, compensation and other project requirements. Under the terms of the MOA, Metro has committed to Implementing specific mitigation measures, construction of Metro conveyance system improvements, and the funding of wetland/wildlife enhancement and community facilities. Also under the terms of the MOA, the City of Renton has agreed to use Its best efforts to expedite project review for permits to allow Metro to begin construction by mid-August 1991. Mitigation measures, which Metro and the City of Renton agreed to, are contained in Exhibit B of the attached Memorandum of Agreement [Attachment No.41. Under the Mitigation and Compensation section of the MOA (Section 4), Metro has agreed to fund up to $3,500,000 for the acquisition of riparian wetlands and uplands that could serve as habitat for wildlife within 2500 feet of the plant boundary. These wetland/wildlife Improvements shall be permanently dedicated to the public for the purposes of wildlife preservation and enhancement, including possible use by the City for interpretive trail purposes. Under the Mitigation and Compensation section of the MOA, Metro has also agreed to fund $2,500,000 for public service and community Improvements within the City of Renton. These Improvements would enhance the City's ability to respond to emergencies pmlmrpt PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 6 occurring at the wastewater treatment plant, such as a fire, explosion, hazardous material spill or chlorine leak. These could consist of various types of improvements such as a City fire station and/or emergency response training facility. Metro has also agreed In Section 5 of the MOA to construct several off-site sewage conveyance system Improvement projects related to the proposal. These include: the Cedar River Trunk Relocation; the May Valley Interceptor Extension; and the Cascade Siphon/Footbridge. These projects will be subject to separate permitting and environmental review processes. Other system improvement projects may be added by mutually written agreement of the City and Metro. The estimated total cost of the system Improvement projects Is $4,755,000 which will be solely borne by Metro. The City of Renton has agreed to reimburse Metro for design and construction costs associated with any local sewerage facility improvements. The commitments outlined above are contingent upon Metro becoming legally entitled to begin Phase A construction by mid-August 1991. However, even if Metro is not legally entitled to proceed with construction on its site by mid-August 1991, but the City has become legally obligated to purchase Wetland/Wildlife improvements, Metro has agree to remit these funds to the City for a period of up to 12 months. 4. DEPARTMENTAL COMMENTS Various City departments have reviewed and commented on the proposal. The majority of departments recommended approval of the proposed Metro Wastewater Treatment Plant, Expansion III with conditions. Comments are attached. The context of these comments and recommended conditions is addressed in the text at the end of this report. 5. CONSISTENCY WITH SITE PLAN REVIEW CRITERIA: Section 4-31(d)(1) lists ten criteria that the Hearing Examiner is asked to consider along with all other relevant information in making a decision on a Site Plan Approval application. These include the following: a) Conformance with the Comprehensive Plan its elements and policies: The Renton Comprehensive Plan designates the subject site as "Public/Quasi- Public" to which this project fully complies. The use of the subject site as a municipal utility has long been established in a series of land use actions starting In 1965. Initial projects of the second expansion of the Wastewater Treatment Plant were approved on July 12, 1983, by Conditional Use Permit, File No. CU- 007-83, and the remainder of the second expansion was subsequently approved on October 22, 1987, File Nos. SA-061-87, SP-062-87. The proposed Expansion III contained in this application is an amendment to the earlier land use applications. The proposal is consistent with the applicable general goals, policies and objectives of the City's Comprehensive Land Use Plan, and the area specific policies of the Green River Valley Plan. Specific goals which apply to this project include: Land Use: To promote development of the Valley in a diversity of high quality industrial uses, together with commercial and office uses; Environmental: To ensure that development of the Valley is harmonious with the natural environmental setting, while minimizing pollution and other adverse environmental impacts; and Urban Services: To promote the adequate provision of utility services (including storm drainage control), community facilities, and recreational opportunities in the Valley. The proposal is also consistent with the Utilities Policies which specifies that Development within the Valley should be served by adequate utilities. b) Conformance with existing land use regulations: The subject property is zoned: P-1 (Public Use). This zone requires the reviewing body to ascertain and determine that "the general design and development conform with the adjacent surroundings, meet applicable building and zoning code requirements, comply with the Comprehensive Plan, and has adequate and safe traffic circulation and access." The proposed site plan generally addresses the development standards required for this zone. Minor modifications of the plans may be allowed to achieve full compliance with the Site Plan Review Ordinance (4-31-33). prelmrpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 7 c) Mitigation of impacts to surrounding properties and uses: The proposal includes actions to minimize potential impacts on surrounding properties. A list of mitigating measures which Metro has agreed to are contained In the Memorandum of Agreement for the project. The MOA also includes other actions, which Metro has agreed to implement, for wetland/wildlife enhancement and community/public service facilities, and Metro conveyance system improvements. Perimeter berming and landscaping are proposed to help screen and buffer the plant facilities from uses in the surrounding neighborhood. Interior landscaping is also proposed to visually breakup large open areas. Exterior lighting will be shielded from adjacent properties. Modifications are proposed to existing and new facilities to control odors to meet a design standard of five odor units at the plant's property boundary. Examples of odor control modifications include: ventilation and pre-chlorination of the influent sewer; taller stack for exhaust from the Raw Sewage Pump Station; covering and ventilating liquid treatment processes; enclosure and exhaust scrubbing of the Grit Cyclone Building; reduction of foul air emissions from digesters; and odor scrubbing and taller dispersion stacks from other facilities. Acoustical treatment has been incorporated into the design of facilities for noise control. Construction activities will be controlled to minimize noise impacts. For example, construction hours would be restricted to 7:00 a.m. to 7:00 p.m., weekdays. d) Mitigation of impacts of the proposed site plan to the site: The proposed site plan was designed to minimize on-site Impacts. The plan Includes extensive perimeter and internal landscaping. Two existing wetland areas at the northern end of the site will be preserved with a 25 foot buffer strip and a security fence. Erosion control practices during construction are proposed to minimize soil impacts. Additional storm water run-off from plant expansion requiring treatment, would be treated on-site and discharged to Puget Sound via the Effluent Transfer System (ETS). The proposal and FSEIS discuss potential hazardous conditions from the Chlorine Building and Sulfur Dioxide area during construction and operations. Use and handling of these and other potentially hazardous chemicals and materials should be discussed In the Emergency Management Plan for the plant. e) Conservation of area-wide property values: The facility expansion, when fully implemented as proposed, will eventually enhance the visual appearance of the site, making the facility more visually compatible with adjacent office park development and thus, ensure area-wide property values. f) Safety and efficiency of vehicle and pedestrian circulation: No major off-site vehicular circulation modifications are proposed. Minor on-site circulation modifications are proposed to minimize existing conflicts adjacent to the existing administration building. Some vehicular and pedestrian conflicts could be expected to occur during the construction phase of the project. Temporary signage and signalization may be necessary during construction to minimize these conflicts. g) Provision of adequate light and air: Because many of the treatment processes on site require good aerobic Interaction, the facility has been design for good air circulation both to reduce odors and enhance the treatment process. h) Mitigation of noise, odors and other harmful or unhealthy conditions: Noise levels are expected to Increase during construction. The distance to adjacent existing properties and the slight increase in noise over existing p,.1mrp1 PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 8 background levels should make these impacts minimal. Also, acoustical and odor reduction measures have been designed into the proposed facilities to meet established standards. i) Availability of public services and facilities to accommodate the proposed use: As noted above, in Section D, Public Service, water and sewer are available at the site. Under the terms of the MOA, $2,500,000 would be made available by Metro for improvements to enhance fire and emergency services. j) Prevention of neighborhood deterioration and blight: The subject site is a large industrial complex. Substantial landscaping and berming is proposed to help the proposed expansion fit in with surrounding office- park and other industrial uses. In addition, as specified in the MOA, Metro has committed to fund the acquisition of wetland/wildlife habitat areas within 2500 feet of the site, which would contribute to neighborhood enhancement or maintenance. 6. CONSISTENCY WITH SHORELINE MASTER PROGRAM: This project requires a Substantial Development Permit under the City of Renton's Shoreline Master Program (adopted by Ordinance No. 3758). This section discusses the project's consistency with the Shoreline Master Program. A portion of the proposed plant enlargement Involves approximately six acres of the site within the Shoreline Master Program area of the Springbrook Creek (Springbrook Creek). Springbrook Creek, within the City, is designated as a shoreline of state-wide significance. Proposed development within the shoreline area would include: berming and landscaping, and construction of two of the four proposed Secondary Clarifiers (100 foot diameter), associated piping, a 375 foot extension of the existing Chlorine Contact Channel, minor roadway improvements, and a portion of the perimeter trail and fence around the plant. Under the Mitigation and Compensation section of the Memorandum Of Agreement (Section 4), Metro has agreed to fund up to $3,500,000 for the acquisition of riparian wetlands and uplands that could serve as habitat for wildlife within 2500 feet of the plant boundary, if it is legally entitled to proceed with construction on the site no later than mid- August 1991. These wetland/wildlife Improvements shall be permanently dedicated to the public for the purposes of wildlife preservation and enhancement, including use by the City for Interpretive trail purposes. Such uses are encouraged under the City's SMP: "In this Master Program, priority is also given to planning for public visual and physical access to water In the Urban environment." The Springbrook Creek is designated as an Urban Environment under the City's Shoreline Master Program. The following discussion describes the proposal's consistency with applicable goals, policies and regulations contained in the Shoreline Master Program: a) General Goals and Policies: The proposed Expansion III is generally consistent with applicable goals and policies. The proposal is not a water-dependent activity with respect to the Springbrook Creek Shoreline. [Note: the plant was originally located here to discharge treated effluent into the Green River.] In fact, the proposal could not be a water-dependent use since the Soil Conservation Service owns intervening property between the site and the Springbrook Creek. The proposed expansion, however, minimizes development within the 200 foot shoreline jurisdiction area. The proposal is not anticipated to create offensive or unsafe conditions. The proposal would enhance the shoreline area through development of perimeter landscaping. Proposed shoreline activities will not affect water quality, existing flow, or aquatic and wildlife habitat. Existing public access to the shoreline along the Springbrook Creek would not be affected by the proposal. The proposed "trail for guided tours" along the Springbrook Creek would be within the plant site boundary and perimeter security fence. Public access to the Springbrook Creek shoreline would p,.Imrpt PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 9 not be enhanced by this proposal unless the proposed Perimeter Trail were to be relocated outside the proposed security fence, or preferably onto SCS property. Staff, therefore, encourages Metro to work with the City and the Soil Conservation Service to explore the possibility of relocating the proposed trail to the east on SCS property to better provide public access to the Springbrook Creek shoreline. b) Urban Environment Goals and Policies: The Urban Environment Is designated to accommodate high-intensity land uses, provide for water-dependent activities and encourage public access. The proposed expansion is consistent with the first of these policies, In that the development would intensify the established use within the existing site boundaries. The proposal would not be a water-dependent use because of the intervening SCS property. Public access to the Springbrook Creek shoreline would not be enhanced unless the proposed Perimeter Trail were to be relocated to outside the proposed security fence, preferably onto SCS property. c) General Use Regulations: Pollution and Ecological Disruption. The proposal should not adversely affect water quality or aquatic life along the Springbrook Creek. During construction, Metro proposes to use best management practices for erosion control. [See Attachment No. 1, Applicant's Narrative, p. 27 for erosion control plan.] Aquatic life may be Influenced somewhat by construction activities, including landscaping and berming, however, impacts are considered to be temporary. Because of the distances Involved, no Impacts on the Heron Rookery are anticipated. Use Compatibility and Aesthetic Effects. Proposed facility construction within the shoreline area (Secondary Clarifiers) would be lidded and screened by perimeter landscaping. Proposed facilities would not obstruct views of the Springbrook Creek from adjacent properties or public streets east of the site. The facility's proposed perimeter berming and landscaping is designed to help existing and proposed development blend in better with adjacent developments. Public Access. A perimeter trail for"guided tours"on the landscaped berm along the Springbrook Creek is proposed. This proposal would do nothing to enhance public access along the shoreline of Springbrook Creek on adjacent SCS property. However, public access to the Springbrook Creek shoreline would be enhanced if the trail were relocated to the SCS property which directly abuts the shoreline. Facility Arrangement-Shoreline Orientation. Proposed treatment facilities would be located upland and inland from the water's edge. These would be buffered from the shoreline by the existing and proposed perimeter landscaping (Phases A). Landscaping. The proposal includes extensive landscaping along the site perimeter as well as the interior, some of which is existing with the remainder to be installed in Phases A and C. Unique and Fragile Areas. The proposal would not affect two existing wetlands on site, other than the construction of a security fence at the outside edge of a 25 foot buffer. In addition, under the terms of the MOA, Metro has agreed, for a period of up to one year after signing the MOA, to fund the acquisition of off-site wetland/wildlife areas. This acquisition would be dedicated to the public. d) Specific Use Regulations, Utilities: The proposal complies with the Specific Use regulations which call for landscaping and site screening of facilities. Architectural facades and treatment structures are designed to conform with structures on neighboring properties. prelmrpt PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 10 7. CONSISTENCY WITH SPECIAL PERMIT FOR GRADING: A grading permit for this type of facility Is not typically required If the grading is associated with building construction. However, because of the areas and quantities of grading involved, and because the building construction would not occur until Phase B, a Special Permit for grading Is required. Section 4-10-3 defines procedures for issuance of a Special Permit for Grading. To grant a special permit for grading, the Hearing Examiner shall make a determination that the activity would not be unreasonably detrimental to the surrounding area. The Hearing Examiner shall consider, but Is not limited to, the following: a) Size and location of the activity. The project involves excavation of approximately 260,000 cy. of excavation to allow construction of wastewater treatment tanks and other structures, and for construction of perimeter berms. About 100,000 cubic yards of the soil to be excavated for construction purposes will be used as the fill material for proposed perimeter landscaped berms (unless the soil proves to be contaminated). Remaining excavated soil will be stockpiled for backfill following facility construction and for the grading of proposed internal landscaped areas. Preliminary soils analyses does not Indicate the presence of contaminated soils. If encountered, contaminated soils would be transported and disposed off-site. Approximately 45,000 cy. of clean topsoil will be imported for landscaping. Approximately 35,000 cy. of clean structural backfill will also be imported to the site. There will be additional off-site disposal of construction debris, consisting of about 160,000 sf of pavement and 7700 If of curb and gutter. Construction of facilities will also require dewatering of portions of the site during Phase A, Site Preparation, and during Phase B, Facility Construction. Subject to testing for water quality, this groundwater will be used as recharge to maintain site hydrology. If contaminated water Is encountered it will be treated and discharged to Puget Sound via the ETS. Metro is proposing to use City of Renton water for recharging under these conditions. City water capacity could be strained if these volumns were maintained for any calendar period of time. The applicant will need to discuss this proposal for the use of City water further with the City before it can be implemented. b) Traffic volume and patterns. Because of the large number of truck trips associated with the excavation and fill activities, Metro has agreed to prepare a Transportation Management Plan for City review, prior to the start of construction activities. As part of this plan, Metro will provide adequate Information to neighborhoods and businesses affected during construction; will schedule construction operations to minimize Impacts to peak hour traffic operations; and will prohibit construction worker parking on adjacent streets. Metro will also participate In the Grady Way Transportation Benefit Zone. The construction entrance will be off Monster Road SW. c) Screening, landscaping, fencing and setbacks. Excavation, fill and grading for facility construction will occur on the interior of the site and would be screened from adjacent office park development by the proposed perimeter landscaping and berm. Nevertheless, upland properties, such as on Earlington Hill, will still be able to see into the plant's interior, albeit at great distances. The plant expansion will comply with setback requirements: 30 feet along Oakesdale Avenue SW, and 25 feet along Monster Road SW. d) Unsightliness, noise and dust. The proposed perimeter landscaping and berms will visually screen the facility during operations, as well as excavation and grading activities, during construction. Most noise levels from Oakesdale Avenue and the adjacent office park development to the east and the north, according to the EIS, are expected to increase during construction, however, the distance to adjacent properties should make these impacts minimal. As noted above, acoustical and odor reduction measures are designed into the proposed facilities. Metro has agreed to employ prOmrpt PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 11 best management practices to control erosion and sedimentation, minimize fugitive dust generation, and to ensure that handling of dirt Is not detrimental to the surrounding area. Measures would include wetting exposed surfaces, and regular street cleaning. e) Surface drainage. Surface water quality would be maintained during construction under the erosion control plan for the project, which would be consistent with City of Renton requirements for erosion control and sedimentation. Metro will continually monitor sediment and surface water quality. Storm water runoff during project operation will be collected, and may be treated on-site and discharged consistent with NPDES and other applicable regulations such as the City's adoption of the King County Surface Water Drainage Design Manual. Excavation for proposed treatment facilities will extend below the level of groundwater,thus necessitating selective dewatering. The proposed groundwater dewatering system would utilize large diameter area wells. These wells would be operated in conjunction with recharge wells located near existing structures on- site to minimize potential settlement. Preliminary studies indicate the need for dewatering rates of up to 5,000 gpm to control groundwater in deeper excavations. Should the groundwater prove contaminated, it would be treated on- site and discharged via the Effluent Transfer System. The applicant has proposed to use City water for recharging if this should occur. This must be coordinated with the City first. 8. CONSISTENCY WITH LAND CLEARING AND TREE CUTTING ORDINANCE (Routine Vegetation Maintenance Permit): Note: This permit is subject to administrative review and the analysis provided in this report is for informational purposes only. This chapter provides regulations for the clearing of land and the protection and preservation of trees and associated significant vegetation for the following (applicable) purposes: "L" To preserve and enhance wildlife and habitat including streams, riparian corridors, wetlands and groves of trees; and "M" To promote building and site planning practices that are consistent with the City's natural topographical and vegetational features while at the same time recognizing that certain factors such as condition (e.g., disease, danger of falling, etc.), proximity to existing and proposed structures and improvements, interference with utility services, protection of scenic views and the realization of a reasonable enjoyment of property may require removal of certain trees and ground cover. The following discusses the consistency of the proposal with Regulations for the Land Clearing and Tree Cutting and the Development of Property: a) Tree Cutting Plan. The applicant has submitted a land clearing and tree cutting plan. This plan has been reviewed as part of the SEPA review process by Metro. b) Conformance to Performance Standards Set Forth in Section 4-9-13. Proposed tree cutting is limited to areas of new facility construction. No cutting of protected native growth is involved. No cutting would occur within 25 feet of the two existing wetland areas. No cutting would occur within 25 feet of the annual high water mark or 15 feet of the top of the bank of the Springbrook Creek. c) Conditions. All land clearing and tree cutting activities shall be conditioned by the City to ensure that the following performance standards are met which: Protect potential land slide areas; Minimize potential erosion, flooding or water pollution; Preserve aesthetics; and Preserve habitat. The proposal complies with the performance standards. A condition, however, is recommended requiring an erosion control plan prior to removal of any existing vegetation. prelmipl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11. 1991 Page 12 H. DEPARTMENTAL RECOMMENDATION: Staff recommend that the Hearing Examiner determine In favor of the proposed Site Plan Approval, Shoreline Substantial Development Permit, Special Permit for Grading for Metro's Wastewater Treatment Plant, Expansion III (File No. SA;SM;SP-040-91), subject to the following conditions: 1. Site Plan Approval: a) Mitigation Measures: Because of the Impacts Identified in the FEIS for the project, the applicant shall agree to implement all Mitigation measures, as specified in Exhibit B of the attached Memorandum of Agreement [Attachment No. 41, and shall agree to implement the MOA according to its terms and conditions including the following: (1) Wetland Mitigation/Compensation. Because of potential impacts to existing on-site wetlands, and because the proposed use is not water- dependent, as required by the City's Shoreline Master Program, the applicant shall commit to fund up to $3,500,000 for the acquisition of riparian wetland and uplands that could serve as habitat for wildlife within 2500 feet of the plant boundary. These wetland/wildlife improvements shall be permanently dedicated to the public for the purposes of wildlife preservation and enhancement, including use by the City for interpretive trail purposes. (2) Environmental Health/Public Safety Mitigation/Compensation. Because of potential impacts of the project identified in the EIS in the areas of Environmental Health and Public Safety, the applicant shall commit to fund $2,500,000 for public safety and community Improvements within the City of Renton to enhance fire and emergency response to the Wastewater Treatment Plant. (3) Conveyance System Impacts Mitigation. Because of potential impacts on the City of Renton's Sole Source Aquafer and other environmentally sensitive areas from the Wastewater Treatment Plant's sewage conveyance system, the applicant shall commit to design and construct several off-site sewage system Improvement projects and associated local sewerage facility improvements related to the proposal. These shall Include: the Cedar River Trunk Relocation; the May Valley Interceptor Extension; and the Cascade Siphon/Footbridge. These projects will be subject to separate permitting and environmental review processes. Other system improvement projects may be added by mutually written agreement of the City and Metro. The estimated total cost of the system Improvement projects is $4,755,000 which will be borne solely by Metro. The City of Renton has agreed to reimburse Metro for design and construction costs associated with any local sewerage facility improvements, after project completion in 1996. b) Additional Studies Required. Prior to the issuance of any permits for Phase B construction the applicant shall submit and obtain City staff review of the following studies: (1) Generalized Utilities Plans. These shall consist of preliminary plan drawings and calculations for the following utilities: Storm and Surface Water Drainage. This shall identify the location and preliminary size of storm and surface water control facilities needed to meet all of the applicable Core and Special Requirements contained In Chapter 1 of the King County Surface Water Design Manual, which the City of Renton has adopted. Storm and surface water facilities should be preliminarily sized and shown schematically on the site plan. The plan must address prelmrpt PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 13 methods for meeting water quality requirements for the Impervious areas subject to storage of chemicals or vehicular use, prior to direct discharge to the Green River or ETS. Sewer. This shall consist of a report containing engineering calculations that demonstrates the City of Renton Wastewater Utility Department's requirement that surcharging of the Interceptors and adjacent City collector sewers around the Metro Wastewater Treatment Plant will not exceed two feet below the rim of any manhole (approximately elevation 13) within either the Metro or City of Renton systems. Water. This shall Identify fire flow requirements (see Item No. 2 below) and watermain extensions and improvements such as hydrants, fire sprinkler systems, backflow preventers etc. Proposed Improvements shall be shown schematically on the site plan. Plans shall show proposed improvements and utility relocations separately. (2) Fire and Emergency Management Plans/Special Operations Plan for Storage and Handling of Hazardous Materials. These plans shall address the following: Access. Primary and secondary access routes are to be maintained with prior approval of the City of Renton Fire Prevention Bureau Chief. Once established, these emergency access routes cannot be changed without Fire Prevention approval. Water. The applicant must coordinate all interruption of water supply serving hydrants and sprinkler systems with Fire Prevention. Fire Flow. The applicant shall provide sufficient Information regarding building and facility construction to include: type of construction, total area in square feet, type of use including hazardous use of each building or facility. This analysis shall address the specific requirements regarding fire hydrants, fire suppression and alarm systems. Article 80 of the Uniform Fire Code. The applicant shall address compliance with Article 80 of the Uniform Fire Code regarding all storage and dispensing of existing and proposed hazardous materials. All hazardous materials operations at the Metro Wastewater Treatment Plant must meet minimums specified In Article 80 UFC. (3) Landscaping Plans. The applicant shall submit detailed landscaping development plans for the following: Detailed Landscape Plan for Phase C Internal Planting. This plan shall address proposed grading, plant materials and layout, and irrigation for the interior facility landscaping to be developed in Phase C. Detailed Landscape Plan for Additional Perimeter Landscaping in Phase C. This plan shall address the area along the site perimeter not Included in the Phase A planting plan. This is the area along the Springbrook Creek between SW 7th Street and SW Grady Way. This plan shall Include proposed grading, plant materials/layout and irrigation. Implementation of this plan should occur in Phase C, or as soon as possible after adjacent facilities (Chlorine Contact Channel extension) are completed. Note to applicant: The applicant is encouraged to either undertake joint development of a public access trail on SCS prelmrpl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 14 property along the Springbrook Creek, or consider relocating the existing security fence to the upland side of the proposed trail, thus making it more accessible to the public. (4) Roadway Improvement Plan. The applicant shall provide Roadway Improvement Plans for Monster Road SW and the Longacres Drive. These shall run the full length of the property frontage. Plans shall Include, but not limited to, curb, gutters, sidewalks, and street lighting. (5) Traffic Signal Warrant Analysis. The applicant shall prepare a traffic signal warrant analysis for the Intersection of SW Grady Way and Longacres Drive. This Intersection is presently at Level of Service E and should be upgraded to LOS D. (6) Transportation Management Plan. The applicant shall prepare a traffic control plan to be submitted to the City of Renton Transportation Division for construction activities. Proposed truck haul routes should also be coordinated with the City of Renton Police Department. Since Longacres Drive SW south of SW 16th Street is a private road, the plan should address arrangements for use of this street. This should be coordinated with the Boeing Co. (7) Hold Harmless. The applicant shall hold the City of Renton Harmless from any liability should any of the above studies (1-6) result in increased project costs. It is also recommended that the applicant complete and submit these studies for City review, as soon as, possible in order to evaluate cost implications. g) Grady Way TBZ. The applicant shall participate in the Grady Way Transportation Benefit Zone pursuant to City Resolution No. 2627. This is estimated to be $44,091 [213 increased vehicle trips x $207/trip], and should be paid at the time the building permit is Issued. h) Street Cleaning Bond. Prior to Issuance of a building permit, Phase B, the applicant shall post a $5,000.00 bond with the City for street cleaning during construction. 1) Roadway and Infrastructure Repair. Metro shall repair or pay the City of Renton for the repair of any damage to roadways or infrastructure resulting from construction, prior to the Issuance of the final occupancy permit. j) Detailed Erosion Control Plan. Prior to Issuance of the first permit for the project (Grading License), the applicant shall submit an erosion control plan for City staff review. This plan must be also be Included in the applicant's construction contract for Phase A, Site Preparation. k) 2020 Plus Planning Participation. The applicant shall ensure City of Renton participation in all technical reviews of the Metro Wastewater 2020 Plus Study. Participation shall Include the City of Renton Public Works Director and representatives from the Wastewater Utility Section, Long-Range Planning, Current Planning and the Mayor's Office. 1) Security Procedures. Security procedures should be established, In coordination with the City of Renton Police Department, for protection of the wastewater treatment plant, and particularly the outside storage of liquid chlorine and other hazardous materials. The applicant shall also notify Police and Fire in at least 24 hours In advance of any chlorine tank car movements, both Inside and outside the wastewater treatment plant. 2. Shoreline Master Program Substantial Development Permit: a) The same conditions as specified for No. 1, Site Plan Approval, shall apply to this permit. p,elm,pl PRELIMINARY REPORT TO THE HEARING EXAMINER METRO WASTEWATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 15 3. Special Permit for Grading: a) The same conditions as specified for No. 1, Site Plan Approval, shall apply to this permit. 4. Routine Vegetation Management Permit: a) The same conditions as specified for No. 1, Site Plan Approval, shall be administratively applied to this permit. 5. NOTE TO APPLICANT: The above conditions do not absolve the applicant from the responsibility of meeting all City codes, ordinances and regulations. prelmrpt \ 21 r7. MOD 14 ABANOOAiED �� O1 D �•; � I Tv e I ;M E T R w � I I0 S A LSv a d -\\ —" A Municipality of Metropolitan Seattle SA;SM;SP-040-91 APPLICANT Metro TOTAL AREA g4 c, acres PRINCIPAL ACCESS SW Grady Way Via Monster Road SW or Oakesdale Ave SW Via SW 7th St over P-1 Channel EXISTING ZONING P 1 Public Use — EXISTING USE Metro Waste Water Treatment Plant PROPOSED USE Metro Waste Water Treatment Plant, Expansion III COMPREHENSIVE LAND USE PLAN Public/Quasi-Public COMMENTS Located @ 1200 Monster Road SW, Renton __ 1 ■_ Y.� 11 ng�.�:can :, 1,, :. '• a �'� -LU1. /•' q�.-■.•NO r .. I ME RA III. �►.' a/ III/. �. Sun•' •l ■�i was I ruN1'.•.•.•.•.•.• 1.`INLAY.__ +. If wilmo m.mms,Sams..-n-..; -� •rnooaa■.a.. /n/Y u!!lr,:sNNa naN Sams n If a /noaour.No// l �inianomalumon mms! s o.Nouuo/NN�R}�"v� �uGzp1{5 9y�I.rl.•. NNvuN/N,n.a 1•d. ioNlvuN///IaN 1/o/ouuuoaal■ ■r 1 r If Z I'•'• _��� moss::"::::::inommeomasommin 000n r....a • ....Nan' `` � � 000n/ouu NuoN innommummom KNOWN r■uN/N/■N■WN ` RM nuu000N/ou * ��.1,� uu000uuuun\ � ■■/NNNaN a�� `fir-� i■aac•aYa/Nt■ S Ins ,IN 1 n.1/a'///r//a'll/al■■/ u 'oil n■onn/n/o. . III/as///N■IIN N■L iia._r uu uouuuNa■NI f "ii \//Nal IIIaIpaONN N///I 111■Ita/■///a■■aO/■////a1/a ///■ 111/Iua■■//II/a■KRONOR r e No //////■■�.rar III/11///■/■■Y/a■aa/► ' 1//// t///■i 111/11a//■■/■Y/a//■/■ _ �I////O I■/a■I Illal I■//////11■a//■■a �Nl nuuoaN/./n/uon 5 r` WIN 9 wuM..o .nl.a. ,L o/:; - 000 on, IO2"'Nou I//I•/a I 111////■/as/////■/r .� IYYa•.a.Nb//Y: -� 11 IF 1 ri k I � .auuNl uuuo i::IF IF • � - !jly� I 1 - • a 1 � • r • I - , .,-.,+I41NU d I tVNNIUM"JCHvl-v"o PARKS AND RECREATION DIVISION OTHERS: APPLICATIONCOMMENTS OR SUGGESTIONS REGARDING THIS BITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BYS 30 A.M. ON MAY 24,1991 REVIEWING DEPARTMENT/DIVISION: S7�'e� rti42� 4—/9� _APPROVED _APPROVED WITH CONDITIONS _NOT APPROVED ���� 77n s r DATE: SJ NATURE OF D OR AUTHORIZED REPRESENTATIVE REV.5/90 &Y ml 71V1 L M ll It A 11 '1) U IV DATE: May 241h, 1991 TO: Don Erickson Paul Forsander 7 FROM: Randall Parsons# SUBJECT: STORM WATER REVIEW OF REVISED SUBMISSION FOR METRO TREATMENT PLANT EXPANSION: APPLICATION NO. SA; SM; SP-040-91 As noted in my memorandum to you of March 12, 1990(enclosed for reference),the storm water management for this facility must comply with Chapter 4-22"Storm and Surface Water Drainage" of the City Code. in particular, it should be noted in Section 4-22-5"Submission of Drainage Plans Required;" (also enclosed for reference)that a drainage plan shall be submitted for approval for Site Plan Approvals. I have noted in my memorandum of March 11, 1991 to you that I feel that it is reasonable to consider such a drainage plan as conceptual (not full construction plans)but of sufficient detail on the Site Plan, and with preliminary calculations provided, to identify the location and preliminary size of storm and surface water control facilities needed to meet all of the applicable Core and Special Requirements contained in Chapter 1 of the King County Surface Water Design Manual which we have adopted. This is important in that surface water quantity and quality control facilities will normally have significant impacts on a project's site plan. It is,therefore,particularly important that these facilities be preliminarily sized and shown schematically on the site plan proposed to be approved for this project,which they have not yet shown. In particular for this project will be the methods by which they will meet the water quality requirements for the impervious areas subject to storage of chemicals or vehicular use prior to direct discharge to the Green River. One option may be for them to collect runoff for up to the 2 year storm event (95% of the total runoff volume)and direct it for treatment in the Plant with storm water flows in excess of this quantity directed to the outfalls to the River. Please give me a call at extension 5548 if you have any queslions.regarding these comments. rLMIVIVIIVl7 OE IQ nJvIUMLOLnVIULO _PARKS AND RECREATION DIVISION OTHERS: COMMENTS OR SUGGESTIONS REGARDING THIS APPLICATION SHOULD BE PROVIDED IN WRITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BY 8:30 A.M. ON MAY 2401991 REVIEWING DEPARTMENT/DIVISION: 9alrVS eYJI �rca�loY1 APPROVED APPROVED WITH CONDITIONS NOT APPROVED DATE: —KGNATUfft&rDIAECTOR OR AUTHORIZED REPRESENTATIVE REV. 5/90 dm ht DATE: May 29, 1991 TO: Paul Forsander, Project Manager FROM: Sam Chastain, Parks & Recreation Director SUBJECT: Metro Waste Water Treatment Plant Expansion I have reviewed the proposal as submitted, and I have the following concerns: 1) I would recommend that the proponent explore the possibility of constructing a trail for pedestrians along the east property line adjacent to the SCS property along the P-1 Channel. If a trail is not feasible on the Metro property, I would recommend as part of the mitigation for recreation that the proponent negotiate an easement with SCS for a recreational easement and construct the recreational trail along the P-1 Channel. 2) I would recommend the 1% Arts Works proposal be incorporated as part of the trail system being proposed around the Metro plant boundaries. Also, I suggggest a security fence be placed in a fashion to accommodate the public wishins to use the trail system. I would not recommend a system where potential users check in at a security gate prior to using the trails. 3) I would recommend that detail landscaping plans be submitted prior to a grading permit being issued. I would also recommend additional landscaping be provided along the Metro property along Oakesdale and the P-1 Channel. SC:wr MEMP POLICE DEPARTMENT DEVELOPMENT SERVICES DIVISION CONSTRUCTION FIELD SERVICES DEVELOPMENT PLANNING PLANNING &TECHNICAL SERVICES PARKS AND RECREATION DIVISION —OTHERS: COMMENTS OR SUGGESTIONS REGARDING THIS APPLICATION SHOULD BE PROVIDED IN WRITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BY 8:30 A.M. ON MAY 24,1991 REVIEWING DEPARTMENT/DIVISION: POI u e2 �Z) APPROVED _APPROVED WITH CONDITIONS NOT APPROVED U(Lcr CW(()La ,vLu v0ut_OkA� DATE: ICJ CI SIGNATURE OF DIRECTOR OR AUTHORIZED REPRESENTATIVE REV. 5/90 ds ht DATE: May 28, 1991 TO: Paul Forsander, Project Manager FROM: Penny Bryant, Police Department SUBJECT: METRO REGIONAL TREATMENT PLANT- ENLARGEMENT III The police department is concerned about the traffic that is proposed to be generated by the treatment plant expansion. Once the plant is complete,the traffic increase is relatively small. The greatest concern however,is during the construction phases when it appears that there will be in excess of 400 vehicle trips per day. The city frequently requires advanced approval of "haul routes." This seems like a reasonable requirement considering the volume of trips expected with this expansion. The police department has is the past received numerous odor complaints,especially during the summer months. However, the application narrative indicates that the tank covers will be "fixed" to improve odor release. The metro site is a secured site. However,there is concern about the possible access to the chlorine facilities that pose a grat health threat. Accordingly,we would like to know what security measures are taken surrounding the storage and access to the chlorine facilities. DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS DEVELOPMENT APPLICATION REVIEW SHEET APPLICATION NO(S).: SA;SM;SP-040-91 PROPONENT: Municipality of Metropolitan Seattle (METRO) PROJECT TITLE: Metro Plant Expansion, III BRIEF DESCRIPTION OF PROJECT: Three phase expansion of Metro Treatment Plant at Renton: One: Site Preparation (excavation, fill and grading) and Perimeter Landscaping; Two: Facility Construction;Three: Interior Landscaping and Site Clean-up.. LOCATION: SEC: 24 TWNSHP: 23N RNG: 4E 1200 Monster Rd SW, Renton TO: PUBLIC WORKS DIVISION SCHEDULED TAC DATE: 5/24/91 ENGINEERING SECTION TRAFFIC ENG. SECTION UTILITIES ENG. SECTION FIRE PREVENTION BUREAU POLICE DEPARTMENT DEVELOPMENT SERVICES DIVISION CONSTRUCTION FIELD SERVICES DEVELOPMENT PLANNING PLANNING &TECHNICAL SERVICES PARKS AND RECREATION DIVISION _OTHERS: COMMENTS OR SUGGESTIONS REGARDING THIS APPLICATION SHOULD BE PROVIDED IN WRITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BY 8:30 A.M. ON MAY 24,1991 REVIEWING DEPARTMENT/DIVISION: �V�L�Gl7 "ht4111 AV APPROVED APPROVED WITH CONDITIONS NOT APPROVED DATE: SIGNAT RE OF DIRECTOR OR AUTHORIZED REPRESENTATIVE REV. 5/90 do ht J: Teuudcal AdvlsorYUUM11111tee FROM: Paul Forsander, Project Manager SUBJECT: METRO WASTE WATER TREATMENT PLANT-Expansion III - Proposed Site Plan Approval Conditions. Application No. SA;SM;SP-040-91 The Metro Waste Water Treatment Plant Expansion III is scheduled for Hearing Examiner Site Plan Review on June 11, 1991. As you are aware It is incumbent upon the City under the terms of the Memorandum of Agreement to "make best efforts" to facilitate permit review and approval by that date. Failure to do so would mean loss of the $6 million specified for compensation by Metro under the M.O.A.. Concern has been expressed by several of the reviewing departments over the adequacy of Metro's submittal In areas of: transportation, utilities and landscaping. After reviewing the Site Plan Approval Ordinance, I believe we can recommend Site Plan Approval by the Hearing Examiner and still satisfy the concerns of the reviewing departments. Authority for Hearing Examiner Approval. Section 4-31-33 provides for Hearing Examiner Approval if the proposed Site Plan Is consistent with the general purposes of the Section and review criteria. The Section also allows the Hearing Examiner to place reasonable conditions on, or modify, a site plan In order to satisfy the general purposes of the Section or achieve consistency with the site plan criteria. Recommendations for Site Plan Approval. I believe the Metro Waste Water Treatment Plant Site Plan for Expansion III meets the general purposes of Section 4-31-33 and satisfies most of the review criteria except In areas such as: utilities, transportation /streets and landscaping. I also believe that the plans and Improvements required for each of these areas would not materially change the overall site plan concept or Its Impacts. Therefore, I propose that we recommend that the Hearing Examiner Approve the Site Plan with the following conditions: 1. Phasing: As proposed, the Project would be accomplished in three phases: Phase "A" (1991/1993) Includes Site Preparation (excavation, fill and grading) and Perimeter Landscaping (except for the area along P-1 Channel between Grady W. and SW 7th); Phase "B" (1993/1995) Includes building and treatment facility construction; Phase "C" (1996) includes construction clean-up and Internal landscaping. Conditions should be placed on project phasing to require additional project design and construction to make the Site Plan consistent the general purpose and criteria of Section 4-31-33. These conditions are specified In items 2 and 3 following: 2. Facility Planning and Design. Prior to the Issuance of any permits for Phase A (approximately Issuance date of permits for Grading, Landscaping and Routine Vegetation Maintenance is Mid-August 1991), Metro shall submit and obtain City Staff Review of the following planning and design studies: a. Detailed Landscape Plan for Phase C Internal Planting. This shall Include proposed grading, plant materials/layout and irrigation. b. Detailed Landscape Plan for Phases B&C This shall address Perimeter Landscaping along the P-1 Channel for the area between SW 7th Street and SW Grady Way. c. Potential Joint Development Plan for SCS Property Along P-1 Channel. This plan shall address potential joint development for landscaping and a public trail on SCS property along the P-1 Channel abutting the Metro site.. d. Generalized Utilities Plans. These shall address compliance with City Code requirements for: water/fire flow, sewer, storm water drainage,and erosion control. e. Transportation/Street Improvement Plan. These plans shall address any Code required Improvements for street paving, curbs and gutters, sidewalks, planting and street lighting. Plans shall also address traffic Improvements such as signalization. f. Emergency Access Management Plan. This plan shall address fire and emergency access requirements during construction. 3. Facility Construction. Metro shall formally commit to Implement the requirements and Improvements Identified In the planning and design studies described in Item 2 , above, as part of the following project Phases: Phase A Metro shall submit and obtain City Review of all planning and design studies specified in Item 2, above, prior to Issuance of the Phase A Building/Grading permit (approx. Mid Aug '91). Metro shall complete all Code required off-site/public right-of-way utility and infrastructure Improvements by the end of this phase. Phase B Metro shall complete the remaining Perimeter Landscaping not Implemented In Phase A along the P-1 Channel property line as soon as possible during this phase (after the construction of the Chlorine Contact Channel Extension is completed). Metro Shall also pursue joint development on SCS property along the P-1 Channel during this Phase. Metro shall also complete all Code required on-site utility and transportation Improvements by the end this phase. Phase C Metro shall complete the Internal landscaping by the end of this phase. DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS DEVELOPMENT APPLICATION REVIEW SHEET APPLICATION NO(S).: SA;SM;SP-040-91 PROPONENT: Municipality of Metropolitan Seattle (METRO) PROJECT TITLE: Metro Plant Expansion, III BRIEF DESCRIPTION OF PROJECT: Three phase expansion of Metro Treatment Plant at Renton: One: Site Preparation (excavation, fill and grading) and Perimeter Landscaping; Two: Facility Construction; Three: Interior Landscaping and Site Clean-up.. LOCATION: SEC: 24 TWNSHP: 23N RING: 4E 1200 Monster Rd SW, Renton TO: PUBLIC WORKS DIVISION SCHEDULED TAC DATE: 5/24/91 ENGINEERING SECTION TRAFFIC ENG. SECTION UTILITIES ENG. SECTION FIRE PREVENTION BUREAU POLICE DEPARTMENT DEVELOPMENT SERVICES DIVISION CONSTRUCTION FIELD SERVICES DEVELOPMENT PLANNING PLANNING &TECHNICAL SERVICES PARKS AND RECREATION DIVISION _OTHERS: COMMENTS OR SUGGESTIONS REGARDING THIS APPLICATION SHOULD BE PROVIDED IN WRITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BY 8:30 A.M. O11Nl MAY 224,1991 !! � I� L `V )� 'zll CE•S REVIEWING DEPARTMENT/DIVISION: _APPROVED _APPROVED WITH CONDITIONS / !� NOT APPROVED /'�Cd ��y'a�vtVr41.15 C'`' LL wNl4w.jl.% DATE: SIGNATURE OF DIRECTOR OR AUTHOWLED REPRESENTATIVE REV. 5/90 deem Review Comments Transportation - Development Services Metro Plant Expansion, SA;SM:SP-040-91 May 24 , 1991 1. Participation in the Grady Way Transportation Benefit Zone Mitigations required. 213 (estimated increased vehicle trips) x $207 = $44 , 091. 00 This should be paid at time building permit is issued. 2 . Roadway improvement plans to be provided for Monster Road and for Longacres Drive for the full length of the property frontage. Item included, but not limited to, curb, gutters and sidewalks. 3 . Street lighting plans and provisions to be provided on Longacres Drive and on Monster Road the full length of the property where it abuts the roadway. S W(1'lj� Wad 4 . The intersection of iC� and Longacres Drive is apparently at a service level E. A traffic signal warrant analysis is to be provided. Also, design recommendations for the intersection is to be provided to return the service level back to a D level. 5. A traffic control plan to be submitted to the City's Transportation Division for construction activities. 6. With the amount of hauling, the developer should be committed to a significant bond for street cleaning. Recommended minimum bond for this purpose is $5, 000.00. 7. Items to be addressed, as stated in Mel Wilson's Memorandum to Don Erickson on April 19, 1991. a. Roadway infrastructures resulting from increased truck traffic to be addressed by Metro. An additional mitigation fee for future repairs should be agreed upon. b. Longacres Drive S.W. and S.W. 16th Street is a private road. What arrangements does Metro have which allows them to currently use this road? Will this roadway be available for Metro's use in the future, in light of Boeing's proposed development at the Longacres site? C. Construction operation should be scheduled to minimize impact during peak traffic times. ( 1.) Flagmen may be required at non-signalized intersections (Longacres Drive SW & SW Grady Way in particular) . ( 2 .) The contractor is to coordinate construction routes with the City's Transportation office. d. Metro must repair or pay for the repair of any damage to the roadway, infrastructures resulting from construction. DEVELOPMENT SERVICES DIVISION CONSTRUCTION FIELD SERVICES DEVELOPMENT PLANNING PLANNING &TECHNICAL SERVICES PARKS AND RECREATION DIVISION _OTHERS: COMMENTS OR SUGGESTIONS REGARDING THIS APPLICATION SHOULD BE PROVIDED IN WRITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BY 8:30 A.M. ON MAY 2411991 REVIEWING DEPARTMENT/DIVISION: APPROVED APPROVED WITH CONDITIONS NOT APPROVED ���Tll�-Ti���vl���al[� ��' �i�LA�'r.��nd✓ ���s t'&t>vivie, A rc---r—bv-�r #� �+-l✓�� �l��ct�lLr L`.4L-C�v(.A�iot-�S �l>ct~-L�,+uol,-IS-r�TL=S TS �r�1?1'vu;r1-lT� ��zvc rcEwc�tT -r- Svlrzd��rz�c�.IU- flE� �Tk� lr1T���E�►—orLs �t.1>�Lk���GIFJ�r C�iT( ��Ir �!' I eM6 .Arm /u-ar:� _-r� Ar---raD r-Ae«rry W-,4- OoT- 1�3cL��lGT� �b �6,6�T CirGlA�c1 Aa-1 AlA{ (4lbLC-- GJIT14-ttj YYl�t9o'� �� I� Lt ►-r'>'y ��5-r� DATE: SIGNATURE OF DIRECTOR OR AUTHORIZED REPRESENTATIVE REV. 5/90 do hl REVIEWING DEPARTMENT/DIVISION: U�IAT� APPROVED APPROVED WITH CONDITIONS X NOT APPROVED _ WKIUAtMA EICTCNfiaWS t ,WAW�Eii(S LLI-jLL 3E 2C-6,WW -m Pecaioc- kffvAle f1111E ftfl(ct5L*J 'TD P2005 E0 'iNioat]ENINfs le: ItY0YMJ1Tt F18C -WiLlkLm S'isSe I, I if Ahtt;(ABIt ) IuilT' ?C"ftf SAFE IfPAIW6 unuiiiES 'IHOttdurtteN% PIAVL 4 UbLi�t1E, - .SLI6SC><X -1b M.L A9iUtAGIE WaMiC FEES AT 67G D&)Ek lrfl6jT Y1ftw,L, &Wod _ WIN-Am ufiuy DATE: Hm 2q. )ri�11 SIGNATURE OF DIRECTOR OR AUTHORIZED REPRESENTATIVE REV.5/90 d..hl DEVELOPMENT SERVICES DIVISION CONSTRUCTION FIELD SERVICES DEVELOPMENT PLANNING PLANNING &TECHNICAL SERVICES PARKS AND RECREATION DIVISION OTHERS: COMMENTS OR SUGGESTIONS REGARDING THIS APPLICATION SHOULD BE PROVIDED IN WRITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BY 8:30 A.M. ON MAY 24,1991 REVIEWING DEPARTMENT/DIVISION: —APPROVED _ZAPPROVED WITH CONDITIONS NOT APPROVED Af 5� CC�eeily /w 4 `e .ylc�tcs . 1P,t* �t �a �4+ 4- r �✓ 2c GCdf� �1�i1 DATE: NATUR OF DIRECTOR OR AUTHORIZED REPRESENTATIVE CeW REV. 5/90 davmhl REVIEWING DEPARTMENT/DIVISION: APPROVED APPROVED WITH CONDITIONS NOT APPROVED .7-'b � DATE: SIGNATURE OF DIRECTOR OR AUTHORIZED REPRESENTATIVE REV. 5/90 drn hl eou%�sunn YE •• _ - _ -41E 51C: "`"_ ._ pEF�TP NV %OI.W _. UR WIS WT IEVKrvJI � 1 :\�." �� NEiQQ112 al&W ARIA RNN 00 rUt I ) / . II . a, IN'INE`' t , .smart W - arw mwv GA 1 Tt E T R O EN,,.m T EMETRO REE�� "�a ^E�EF of wre ur.Y 20.1NI N. . ON , ., ^�- ti wP.roe urt. Oo r-l- Y IP cw PEFEftENCE 4E C YJv Y✓AN. 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ITS xg ■ ORDINARY HIGH WATER LINE p_i CHANNEL BERMING OW BERMING ORNE BULDNG DIGESTERS OAKESDALE ROA r l / /.r • .� r / / 1' r SHORELINE.AIMSDICTIONAL BOUNDARY rim /: 1 `• C 1 14` � �F {I I ' LOW BERMING i. 4. -' a � r:Y; 'FACLLRY NTERIOfl" �L "• Z iS ,VT, r:" WETLAND 1 1 \ y WATERTDWER NEW BERMING ,moo w NEW BERMING ADMINISTRATION BUILDING MONSTER ROAD — Y I. �.,.� •.-.✓ FACLLITY ENTRANCE VRO'MfD CO WN ESKTRIG CO TWA QRAFlWPE 61 CONCEITUAL K W A NiT110 TpEATIEW KI1NT AT RENTOM W iT1ETR0 vuYYAT °_p - g I / PROPOSED BUCK RIVER PARK -- PHASE 1 � y PBLACK RIVER PARK PHASE pjI 11 - - \\ R Ymuuna � y �'�, l `�'•� l l l l l l l l l l l l l l lll11, illllllV ar° iiil ' llll'I lllilllilill/ lllll;ll;l, •,ilil. lilllllly liltill,l 'illy' 1lll�'� D + + + ++IRA+ �� �� YEIRO RE(P011Y.TP£AIYEMT RANT W flQiTpl " METRO EY: vi cn.riu€c R1s -- R9F.. LvJo ' L{1] V I jm- n �LN ntlLx na weuzuai� ..:vci ` _ � -.�J � E.IDN✓R r rj' JL R wad rtaRp� � i 1: 4EFERENLE: _ L41 - .frt L42] 1 r..w. Q f L{2{` x1 µ2Sa— .. i l{26 1420 'sr r - x.�zrt� t ._j 40 - ,- [px1InF19x.u�.ftlExi I BC CO nNrvNi CISX PEHTON m.� �W YM- 1 e e 1 i e 3�R 0/W YCWIxI—._ m� ; 6LY,IOI�..Y�\ MYYIf aY.YI.,MWYO I i i . � S LM� - e, YAW�Y�.WmY.a« I i �WpOJA OYIYII� � 51 i !1 mznnl-- Y]Foe YI.M tl�bl FM— WSOSM I � Q --- i e e f e e t m oy Z . 8� eno¢ —�aYcmu. i i l 1 1 1 1 1 1 —IYPSIPm -- -IPNt � .—LM¢N II OIMQ P4Mnl —.—.—LW MY �9VM IEf[WL m Pn umz —swat nww m¢w � NY out um rc x°o —mP amP,uY mxsn a¢srsn swe r.mx amrzn "�m�0mn°:tvx�u itv mw¢z�m a,o¢Yamw tuw N �n F o -SIYZY¢N 4>M 2 �IIYMt S6 t.¢X\Mxf 1 1 i � MY.nox e anf -Y�tltlt SPepB[nz1W S[LV4MY m019AlVRRf IC.fgmf,YfW.ml!ADt Letl -,f.IlOun�f6.alI.1W,NYf.b ■� —¢mn srau¢tux J^Y��Tq rzzww zmn.a,ux O mP Idm'Iq,,Pa E 8� —nnt a¢s,m.w¢•m+c tux n,00v g�F ri aaMn a m sID xm¢ pr64 _ma¢m,.twc xea.nm•xum 2� —ownrta yp_ —i orrmn[ G�y 1 1 I Z 2 + t f / 99 .£ LY � .n.� /` / �� � � f „w 1{i to a •bf f ! ILfp oaoti 'rz om / � � i �: i / �" % • / Fr+ata.�1¢awsn+.ti'aw'na.�e'L5!'1b45 r'1 ' / �� � J P / 2Crvl�Ro•DNwY MMD PE�•[TEA. K 'w1 ' ' /' � ', / ' �; _/ �/3,g,• , �,n tc�eerx�c'rn+la.v4n.,wrp nets /' ///'"/ EpM1EEN tA.E 61R.•a. rasE LR ar.E _ �- . v.i7ux/SE MAMX4•4W BYBra= and CaldwoU COn Sultanis ��� "g >n•o.••bi�mweauie PLANTING PLAN a L•. AREA 24 ♦ wrw uc sx w...c un R / r/ ' �' J j•l � •r � II tiY.itt • .. 10 JnJ •' •MI�C2Y .iG UM SQ 04r! 4S4 pILMW CJn$Ult Ctl!5 yam. e A rR R.uM/10[IDI.MYJf '�ssn.. .•,...Pa I Imo___ I PLANT 2E AN L616 - . i.•i � i I ! AREA ER 2E MEMORANDUM M� To ' �Li�S Date From Subject- ;' z 1016,0e MIX 4A 7 PRELIMINARY REPORT TO THE HEARING EXAMINER DRAFT METRO WASTE WATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING •/%�l/f/.�,1 June11, 1991 Page 9 Construction of facilities will also require dewatering of portions of the site, particularly during Phase A, Site Preparation. Subject to testing for water quality, this ground water will be used for recharge to maintain site hydrology. if contaminated water Is encountered It will be treated and discharged either to the Green River or to Puget Sound via the ETS. b) Traffic volume and patterns. Because of the large number of truck trips associated with the excavation and fill activities, Metro has agreed to prepare a Transportation Management Plan for the construction activities. Metro will provide adequate information to neighborhoods and businesses affected during construction; will schedule construction operations to minimize Impacts to peak hour traffic operations; and will prohibit construction worker parking on adjacent streets. Metro will also participate in the Grady Way Transportation Benefit Zone. The construction entrance will be off Monster Road SW. c) Screening, landscaping, fencing and setbacks. Excavation, fill and grading for facility construction will be located on the Interior of the site and would be screened by the proposed perimeter landscaping and berm. The plant expansion will comply with setback requirements: 30 feet along Oakesdale Ave. SW and 25 feet along Monster Road SW. d) Unsightliness, noise and dust. The proposed perimeter landscaping and berms will visually screen the facility during operations, as well as, excavation and grading activities during construction. Nolse levels are expected to Increase during construction, however, the distance to adjacent properties should make these Impacts minimal. Acoustical and odor reduction measures are designed Into the proposed facilities. Metro will employ best management practices to control erosion and sedimentation, minimize fugitive dust generation, and to ensure that handling of dirt Is not detrimental to the surrounding area. Measures would Include wetting exposed surfaces, and regular street cleaning. e) Surface drainage. Surface water quality would be maintained during construction under the erosion control plan for the project, which would be consistent with City of Renton requirements for erosion control and sedimentation. Metro will continually monitor sediment and surface water quality. Storm water runoff during project operation will be collected,treated on-site and discharged via the ETS. Excavation for proposed treatment facilities will extend below the level of ground water thus necessitating selective dewatering. The proposed groundwater dewatering system would utilize large diameter area wells. These wells would be operated In conjunction with recharge wells located near existing structures on-site to minimize potential settlement. cole nt Preliminary ater In deeper udies Indicate the need for dewatering rates of up to 5,000 gp of 9round excavations. Should the groundwater prove contaminated, it would be treated on-site and discharged via the ETS. H. DEPARTMENTAL RECOMMENDATION: Staff recommend that the Hearing Examiner determine In favor of the proposed Site Plan Approval, Shoreline Substantial Development Permit, Special Permit for Grading, and Routine Vegetation Management Permit for Metro's Waste Water Treatment Plant, Expansion III (File No. SA;SM;SP- 040-91), subject to the following conditions: 1. Site Plan Approval: a) The applicant shall agree to Implement all Mitigation measures, as specified In Exhibit B of the attached Memorandum of Agreement [Attachment No.31 prelmrpt PRELIMINARY REPORT TO THE HEARING EXAMINER DRAFT �/1/'��S METRO WASTE WATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 10 b) The applicant shall contract with the City of Renton and commit to fund $3,500,000 for the acquisition of riparian wetland and uplands that could serve as habitat for wildlife within 2500 feet of the plant boundary. These wetland/wildlife Improvements shall be permanently dedicated to the public for the purposes of wildlife preservation and enhancement, including use by the City for Interpretive trail purposes. c) The applicant shall contract with the City of Renton and commit to fund $2,500,000 for community Improvements within the City of Renton. These could consist of various types of Improvements such as a City fire station and/or emergency response training facility. d) The applicant shall contract with the City of Renton and commit to design and construct several off-site sewage system Improvement projects and associated local sewerage facility Improvements related to the proposal. These shall Include: Cedar River Trunk Relocation; May Valley Interceptor Extension; and Cascade Siphon/Footbridge. These projects will be subject to separate permitting and environmental review processes. Other system Improvement projects may be added by mutually written agreement of the City and Metro. The estimated total cost of the system Improvement projects Is $4,755,000 which will be borne by Metro. The City of Renton has agreed to reimburse Metro for design and construction costs associated with any local sewerage facility Improvements. e) Prior to the Issuance of any permits for Phase A construction (Approximate Issuance date of permits for Grading License, Landscaping and Routine Vegetation Management Permit Is Mid-August 1991), the applicant shall submit and obtain City staff review of the following studies: 1. Generalized Utilities Plans. These shall consist of preliminary plan drawings and calculations for the following utilities: Torm and Surface Water Drainage. This shall identify the location and preliminary size storm and surface water control facilities needed to meet all of the applicable Core and Special Requirements contained in Chapter 1 of the King County Surface Water Design Manual, which the City of Renton has adopted. Storm and surface water facilities should of be preliminarily sized and shown schematically on the site plan. The plan must address methods for meeting water quality requirements for the Impervious areas subject to storage of chemicals or vehicular use, prior to direct discharge to the Green River or ETS. Sewer. This shall consist of a report containing engineering calculations that demonstrates the City of Renton Waste Water Utility Department's requirement that surcharging of the Interceptors and adjacent City collector sewers around the Metro Waste Water Treatment Plant will not exceed two feet below any manhole (Invert elevation_)within either the Metro or City of Renton systems. Water. This shall identify fire flow requirements (see Item no. 2 below) and watermaln extensions and Improvements such as hydrants, fire sprinkler systems, backflow preventers etc. Proposed Improvements shall be shown schematically on the site plan. Plans shall show proposed Improvements and utility relocations separately. 2. Fire and Emergency Management Plans/Special Operations Plan for Storage and Handling of Hazardous Materials. These plans shall address the following: Access. Primary and secondary access route to be maintained with prior approval of the City of Renton Fire Prevention Bureau Chief. Once established, these emergency access routes cannot be change without Fire Prevention approval. Water. The applicant must coordinate all Interruption of water supply serving hydrants and sprinkler systems with Fire Prevention. Fire Flow. The applicant shall provide sufficient Information regarding building and facility construction to Include: type of construction, total area In square feet, type of use Including hazardous use of each building or facility. This analysis shall address the specific requirements regarding fire hydrants, fire suppression and alarm systems. Article 80 of the Uniform Fire Code. The applicant shall address compliance with Article 80 of the UFC regarding all storage and dispensing of existing and proposed hazardous materials. All hazardous materials operations at the Metro Waste Water Treatment Plant must meet a minimum specified In Article 80 UFC. prelmrpt PRELIMINARY REPORT TO THE HEARING EXAMINER DRAFT METRO WASTE WATER TREATMENT PLANT, EXPANSION III PUBLIC HEARING June 11, 1991 Page 11 3. Landscaping Plans. The applicant shall submit detailed landscaping development plans for the following: Detailed Landscape Plan for Phase C Internal Planting. This plan shall address proposed grading, plant materials and layout, and Irrigation for the Interior facility landscaping to be developed In Phase C. Detailed Landscape Plan for Additional Perimeter Landscaping. This plan shall address the area along the site perimeter not Included In the Phase A planting plan. This is the area along the P-1 Channel between SW 7th Street and SW Grady Way. This plan shall Include proposed grading, plant materials/layout and Irrigation. Implementation of this plan should occur In Phase B as soon as possible after adjacent facilities (Chlorine Contact Channel extension) are completed. Joint Development Plan for SCS Property along the P-1 Channel. This plan should address potential for joint development for landscaping and a public trail on Soil Conservation Service property along the P-1 Channel abutting the Metro site. f The applicant shall participate In the Grady Way Transportation Benefit Zone mitigation required. This Is estimated to be $44,091 [213 increased vehicle trips x $207/trip], and should be paid at the time the building permit Is Issued. g) Prior to Issuance of a building permit, the applicant shall provide Roadway Improvement Plans for Monster Road SW and the Longacres Drive. These shall run the full length of the property frontage. Plans shall Include, but not limited to, curb, gutters, sidewalks, and street lighting. h) Prior to Issuance of a building permit, the applicant shall prepare a traffic signal warrant analysis for the intersection of SW Grady Way and Longacres Drive. This intersection is presently at Level of Service E and should be upgraded to LOS D. I) Prior to Issuance of a bullding permit,the applicant shall prepare a traffic control plan to be submitted to the City of Renton Transportation Division for construction activities. The plan should also address additional fees for roadway and Infrastructure costs resulting from Increased truck traffic during construction. Since Longacres Drive SW and SW 16th Streets are private roads, the plan should address arrangements for use of these streets. This should be coordinated with the Boeing Co. j) Prior to Issuance of a building permit, the applicant shall post a $5,000.00 bond with the City for street cleaning during construction. k) Metro shall repair or pay the City of Renton for the repair of any damage to roadways or Infrastructure resulting from construction. 1) Prior to Issuance of the first permit for the project (Grading License), the applicant shall submit an erosion control plan for City staff review. This plan must be Included In the applicant's construction contract for Phase A, Site Preparation. mThe applicant shall ensure City of Renton participation In all technical reviews of the Metro Waste Water 2020 Plus Study. Participation shall Include the City of Renton Public Works Director and representatives from the Sewer Utility Department, Long-Range Planning, Current Planning and the Mayor's Office. 2. Shoreline Master Program Substantial Development Permit: a) The same conditions as specified for No. 1, Site Plan Approval, shall apply to this permit. 3. Special Permit for Grading: a) The same condltlons as specified for No. 1, Site Plan Approval, shall apply to this permit. 4. Routine Vegetation Management Permit: a) The same conditions as specified for No. 1, Site Plan Approval, shall apply to this permit. prelmrpt CM OF RENTON MEMORANDUM DATE: May 241h, 1991 TO: Don Erickson Paul Forsander FROM: Randall Parsons SUBJECT: STORM WATER REVIEW OF REVISED SUBMISSION FOR METRO TREATMENT PLANT EXPANSION: APPLICATION NO.SA; SM; SP-040-91 As noted in my memorandum to you of March 12, 1990(enclosed for reference), the storm water management for this facility must comply with Chapter 4-22"Storm and Surface Water Drainage"of the City Code. In particular,it should be noted in Section 4-22-5"Submission of Drainage Plans Required:" (also enclosed for reference)that a drainage plan shall be submitted for approval for Site Plan Approvals. I have noted in my memorandum of March 11, 1991 to you that I feel that it is reasonable to consider such a drainage plan as conceptual (not Full construction plans)but of sufficient detail on the Site Plan,and with preliminary calculations provided, to identify the location and preliminary size of storm and surface water control facilities needed to meet all of the applicable Core and Special Requirements contained in Chapter 1 of the King County Surface Water Design Manual which we have adopted. This is important in that surface water quantity and quality control facilities will normally have significant impacts on a project's site plan. It is,therefore,particularly important that these facilities be preliminarily sized and shown schematically on the site plan proposed to be approved for this project,which they have not yet shown. In particular for this project will be the methods by which they will meet the water quality requirements for the impervious areas subject to storage of chemicals or vehicular use prior to direct discharge to the Green River. One option may be for them to collect runoff for up to the 2 year storm event(95%of the total runoff volume)and direct it for treatment in the Plant with storm water flows in excess of this quantity directed to the outfalls to the River. Please give me a call at extension 5548 if you have any questions.regarding these comments. RP:rp tt Dick Anderson Kim Scattarella enclosures 4-n 2 4-22-8 SUBJECT PROPERTY: The tract of land which is B- The plan submitted during one permit the subject of the permit and/or approval action. approval process may be subsequently submitted with further required applications. The plan shall be supplemented with 4-22-4: ADMINISTERING AND ENFORCING additional information at the request of the AUTHORITY: The Director of Public Department of Public Works. Works is designated as the administrator and is responsible for the general administration and coordination of this Ordinance. All provisions of 4-22-6: PLANS NOT REQUIRED: The plan this Ordinance shall be enforced by the Director requirement established in Section and/or his designated representatives. For such 4-22-5 shall not apply when the department purposes the Director or his duly authorized determines that the proposed permit and/or representative shall have the power of a police activity: officer. A. Will not seriously and adversely impact the water quality conditions of any affected —�4-22-5: SUBMISSION OF DRAINAGE PLANS receiving bodies of water and/or REQUIRED: B. Will not substantially alter the drainage A. All persons applying for any of the following pattern, increase the peak discharge and permits and/or approvals shall submit for cause any other adverse effects in the approval, unless expressly exempted under drainage area. Section 4-22-6 hereinbelow, a drainage plan with their application and/or request. Additionally, the plan requirement established in Section 4-22-5 shall not apply to single family 1. Mining, excavation and grading permit; residences when such structures are less than five thousand (5,000) square feet, unless the subject 2. Shoreline management substantial develop- property is in a critical area as determined under ment permit; Section 4-22-7. 3. Flood control zone permit; 4-22-7: DEVELOPMENT IN CRITICAL 4. Major plat; FLOOD, DRAINAGE AND/OR EROSION AREAS: Development which would 5. Short plat approval, except where each lot increase the peak flow and/or the volume of contains thirty five thousand (35,000) square discharge from the existing flooding, drainage feet or more; and/or erosion conditions present an imminent likelihood of harm to the welfare and safety of the 6. Special permits; surrounding community until such a time as the community hazard is alleviated. Where applications 7. Temporary permits; of the provisions of this Section will deny all reasonable uses of the property, the restriction on 8. Building permits. Where the permit relates development contained in this Section may be to a single family residential structure of less waived for the subject property, provided, that the than five thousand (5,000) square feet, the resulting development shall be subject to all of the Director may waive the plan requirement remaining terms and conditions of this Ordinance. except where the subject property is in a (Ord. 3174, 11-21.77) critical area, as determined under Section 4-22-7. 4-22.8: DRAINAGE PLAN REQUIREMENTS 9. Planned unit development; AND METHODS OF ANALYSIS: All persons applying for any of the permits and/or 10. Site plan approvals; approvals contained in Section 4-22-5 of this Ordinance shall provide a drainage plan for surface 11. Any other development or permit applica- water flows entering, flowing within and leaving tion which will affect the drainage in any the subject property. The drainage plan and w'ay, supportive calculation report(s) shall be stamped by 990 CITY OF RENTON MEMORANDUM DATE: April 22, 1991 TO: Don Erickson FROM: David M. Christensen SUBJECT: Metro's DSEIS Metro has complied with all of the Wastewater Utility Section's previous requests except for one issue which requires further clarification. The issue is in regard to surcharging in the vicinity of the Metro treatment plant. Chapter Five impacts and mitigations references the problem and proposed mitigation under surface water resources - Mitigation Operations (5-20). The proposed mitigation needs to be further refined to include language similar to the following: Installation of the new influent pump station and the replacement installation of new backup controls for the influent pumps shall be designed such that surcharging in the vicinity of the Metro Treatment plant will not exceed two feet below adjacent manhole rim elevations for the interceptor and collector sewers. If you have any questions or require additional information, please contact me at X-6212. 91-310:DMC:ps CC: Dick Anderson Randall Persons CITY OF RENTON MEMORANDUM DATE: March 12, 1991 TO: Don Erickson VIA: Dick Anderson FROM: Randall Parsons STAFF CONTACT: David M. Christensen Ron Straka SUBJECT: METRO'S DRAFT SUPPLEMENTAL ENVIRONMENTAL IMPACT STATEMENT (DSEIS) The Storm and Wastewater Utility staff has reviewed Metro's Draft Supplemental Environmental Impact Statement (DSEIS). Our review focuses specifically on storm water and wastewater issues. Our comments are as follows: WASTEWATER UTILITY REVIEW COMMENTS: The DSEIS should be amended to include appropriate mitigation measures to revise Metro's current policy of surcharging to elevation 22, to not allowing the surcharge to exceed two feet below adjacent manhole rim elevations for the interceptors and collector sewers (per our previous memo). Currently the DSEIS only mentions the problem (Pg. 2-7), but does not include specific mitigation measures to correct the potential for raw sewage spills during surcharging. The DSEIS does correctly identify the two projects that directly affect the City (Pg. 2-6). However, prior to approval of the supplemental EIS, an acceptable agreement for commitment to these improvements by Metro shall be entered into by the City of Renton and Metro. If you have any questions regarding the above, please call Dave Christensen at 277-6212. / Metro's Draft Supplemental Environmental Impact Statement (DSEIS) Page 2 STORM WATER UTILITY REVIEW COMMENTS: SECTION: SURFACE WATER RESOURCES - Existing Conditions (page 4-17 through 4-22) The existing conditions section needs clarification and the following is provided to supplement existing information: History of the East Side Green River Watershed Plan (P-1 Channel, Black River Pumping Station and Forebay) a) In 1960 the Valley Cities Renton, Kent, and Tukwila, the King County Conservation District, and Drainage District No. 1 passed a resolution agreeing to participate in a jointly sponsored request for Federal assistance for flood control under the Watershed Flood Prevention Act (PL-566) administered by the Soil Conservation Service. b) In 1965 the Soil Conservation Service developed a detailed work plan for the East Side Green River Watershed Plan. This work plan was approved and funded by the U.S. Congress in 1966. c) This lead to the construction of the Black River Pumping Station and channelization improvement of 0.5 miles of the Black River channel from its confluence with the Green River by the local sponsors with assistance from the Soil Conservation Service in 1971. d) In 1982 the local sponsors withdrew from the East Side Green River Watershed Plan. e) In 1984 the City of Renton reactivated its portion of the East Side Green River Watershed Plan and Between 1984 and 1989 the City of Renton with assistance from the Soil Conservation Service constructed the Black River Pumping Station Forebay and approximately 2,500 linear feet of the P-1 Channel from the Black River Pumping Station Forebay to Grady Way. Other improvements included the construction of the Grady Way Box Culvert, The I-405 box culvert which is currently not operational, and in 1990 the City started construction of the new SW 16th Bridge which is still under construction. All of the construction was accomplished with assistance from the Soil Conservation Service to some degree or another. f) In 1988, the City of Renton conducted an environmental study to determine the adequacy of the 1981 NEPA Environmental Impact Statement for the continuation of the East Side Green River Watershed Plan improvements south of Grady Way. The City along with recommendations from several important resource agencies determined that too many changes had occurred since the original NEPA EIS was development to re-adopt the document. Some of these changes include the regulation and preservation of wetlands, impacts to water quality, the changes in storm water management standards such as on-site detention in the watershed, impacts to fisheries resources, and the availability of continuous simulation hydrologic and hydraulic models. Metro's Draft Supplemental Environmental Impact Statement (DSEIS) Page 3 g) In May of 1990 the City of Renton retained R.W. Beck and Associates and their project team to prepare the supplemental technical and environmental information needed for the preparation of a environmental document which satisfies concerns raised during the determination adequacy study, but still uses the original NEPA EIS as the foundation for the East Side Green River Watershed Plan. Our consultants are currently developing a Hydrological Simulation Program-FORTRAN (HSPF) hydrologic model for the entire East Side Green River Watershed. A hydraulic model is also being developed for the Watershed with the use of the Full Equations Hydraulic Model (FEQ). This phase of work The P-1 channel is the portion of Springbrook Creek between the Black River Pumping Station Forebay to the Grady Way Box culvert which has been re-channeled and improved for flood control purposes. The remainder of 12 miles of channel south of Grady Way is the Existing Springbrook Creek some of which was dredged and re-channeled by King County Drainage District No. 1. in the late 50's to early 60's. The P-1 channel is only approximately 2,500 linear feet long. The East Side Green River Watershed is comprised of the remnants of the old Black River, the P-1 channel, Springbrook Creek, Panther Creek, Garrison Creek, and Mill Creek. The Watershed contains portions of jurisdictional boundaries of Renton, Kent and Tukwila along with portions of unincorporated King County (see attached map). This drainage system does not convey any drainage from the Southcenter area. SECTION: SURFACE WATER RESOURCES - Existing Conditions (page 4-24): The Panther Creek Wetlands/P-9 Channel project is a mitigation project of the East Side Green River Watershed Plan Environmental Mitigation Agreement as approved by the SCS and the local sponsors in 1980. This agreement compensated for the environmental impacts resulting from the approved work plan developed by the SCS and as adopted in the SCS Final EIS for the East Side Green River Watershed Plan. The DSEIS references the Valley Study Project but does not include a description the project. The Valley Study Project includes our current hydrologic and hydraulic modeling work along with the integration of our other planning efforts into a comprehensive plan for the valley. The SW 16th Bridge improvement increases capacity only because the old bridge pilings are being removed from the channel. The channel (Springbrook Creek) is no being improved to P-1 Channel standards at this time. METRO trunk line surcharging and overflow into the P-1 channel, the Black River, and the Renton Wetland did occur during the January 9, 1990 storm not the January 9, 1991 storm. Surcharging may not have occurred during the November, 1991 (not November 1990) storm. The January 9, 1990 storm had a five day rainfall total from January 5th thru the loth of 7.98 inches which is estimated to occur once every 70 years. The 24 hour rainfall total on January 9th was 3 inches which is estimated to be a 30 year storm event (City of Renton January 9, 1990 Storm Report). Metro's Draft Supplemental Environmental Impact Statement (DSEIS) Page 4 SECTION: SURFACE WATER RESOURCES - Impacts/mitigation (page 5-14 - 5-19) Storm water management for the METRO Treatment Plant expansion must be done in accordance with the City of Renton Storm and Surface Water Drainage Ordinance (City Code chapter 4-22). The City has adopted applicable portions of the King County Surface Water Design Manual (KCSWDM) in the Ordinance. The DSEIS identifies WSDOE Draft Storm Water Manual erosion control measures which are adequate, but there are additional measures that could be employed and are listed in chapter 5 of the KCSWDM. The site may have an adequate outlet to the Green River with the old effluent line, but per our City Code the runoff must be treated prior to direct discharge into the Green River by a combination of biofiltration and wet ponds. The storm water direct discharge will be required by the Department of Ecology to comply with the new National Point Discharge Elimination System (NPDES) permit requirements. The estimation of each proposed alternative runoff quantity should be calculated as specified in the KCSWDM. This review does not constitute the Utility's approval of the projects drainage plan. The City will issue a permits after site plan approval and construction plans have been reviewed and approved. STORM WATER UTILITY REVIEW SUMMARY: The Existing Conditions information contained in the METRO Treatment Plant Enlargement DSEIS needs to be clarified and the sites storm water management shall be done in accordance with the City's Storm and Surface Water Drainage Ordinance. If there are any questions regarding these comments please contact Ron Straka at 277-5547. 91-214:DMC:RJS:ps RAE. Ik5E. e �r � r F f 1 V �£` NINe CayNTI Y � lllr lAll OrNnR.'rnr g1 NYInrNINhyNNIAyN x � T UK LOCATION MAP x T. •L'l"IW7` 23 t m — T. 22 \ q ]S N t 1� s C�eN i p M� rr FUTURE PLANNED LAND USE Commercial-Industrial OResidential .mNn.• naUR!c Residential-Agricultural FUTURE PLANNED LAND USE Industrial-Agricultural EAST SIDE GREEN RIVER WATERSHED Open Space PROJECT AREA KING COUNTY,WASHINGTON MAICN rNT � • � rws u•u iu,Ne V CITY OF RENTON MEMORANDUM DATE: March 6, 1991 TO: Lynn Guttmann John Webley Lee Wheeler Dan Clements Dick Anderson Mel Wilson Jim Hanson Jay Covington Don Erickson Gregg Zimmerman Rebecca Lind Gary Gotti Sam Chastain Penny Bryant FROM: Rubin Yu, Senior Plann r SUBJECT: Metro East Division Treatment Plant Enlargement Attached herewith please find a copy of the Preliminary Draft EIS for your review and comment. Due to the tight schedule Metro staff imposed on us, please provide me with your comments on the Preliminary Draft EIS by March 13, 1991. If you have any questions concerning the subject matter, please contact me. R3'mamo-l" CITY OF RENTON MEMORANDUM DATE: February 20, 1991 TO: Rubin Yu FROM: David M. Christenseno SUBJECT: METRO REGIONAL TREATMENT PLANT AT RENTON DRAFT SUPPLEMENTAL ENVIRONMENTAL IMPACT STATEMENT Your submittal of Chapters 2, 3, and 4 of the draft EIS for the subject project have been reviewed by the Utility Systems Division with the following comments: 1) Included within Chapters 2, 3, and 4 shall be consideration and mitigation of the existing and potential impacts of the surcharging of Metro's interceptors and of the adjacent collector sewers. This Division's memo to you dated January 31, 1991 speaks of this concern in greater detail and is attached hereto for your information. 2) The EIS for this project shall include the scheduling and impacts of Metro's proposed interceptors that will be constructed to provide the necessary collection system to meet the capacity requirements for the treatment plant's service area. 3) Since the information provided in Chapters 2, 3, and 4 is not complete at this time (data and text referenced but not provided), this review shall not be considered our final comments for these chapters. If you have any questions, you may contact me at X-6212. 91-153:DMC:ps CC: Dick Anderson Randall Parsons Attachment CITY OF RENTON MEMORANDUM DATE: January 31, 1991 TO: Rubin Yu VIA: Dick Anderson FROM: Randall Parsons SUBJECT: METRO Renton rreatment Plant Enlargement Notice of Scoping Storm and Waste Water Utility Section Comments We believe that METRO needs to incorporate a study of the existing and potential impacts of the surcharging of their interceptors and adjacent collector sewers as part of the impact statement for this enlargement of the Renton treatment plant. This is an important consideration in fight of the surcharging problems that currently occur in the Renton Valley area that may be exacerbated by additional waste water Rows directed to this treatment plant from both additional service in the existing basins and diversion of flows into the basin as described in their notice. The existing and future increased surcharging present significant potential environmental impacts. These impacts include the direct threats to public health from raw sewage exiting the system,traffic hazards caused by sanitary sewer manhole lids being blown off and raw sewage Rowing over the roadway,and impacts to fisheries and wildlife in the adjacent surface water systems:the streams,wetlands and Lake Washington. There are some very critical areas such as near Ripley Lane in the Gypsy Creek Basin where METRO's Eastside Lake Washington Interceptor is exposed and is situated several feet above the surrounding ground. We would expect this surcharge study would strive to provide a maximum wet weather peak hydraulic grade line at least two feet below adjacent manhole rim elevations for the interceptors and collector sewers. The study should address existing and the phased increase of Rows from increased service and diversion including proposed new interceptors parallel to the Valley and East Lake Washington Interceptors. If you require any information we have impacts of existing surcharging,or you require any additional information regarding Renton's collector sewers,please contact Mike Benoit at extension 6206. RP:rp rC "A METRO Municipality of Metropolitan Seattle Exchange Building ® 821 Second Ave. o Se '• fVx/� RECEIVED February 13 , 1991 /Y FS 15 1991 ✓K yors ct Hon. Earl Clymer �� e Mayor, City of Renton 200 Mill Avenue South i Renton, Washington 98055 METRO Regional Sewage Treatment Plant Expansion Dear Mayor Clymer: Expansion of Metro' s treatment plant in Renton is well into design. We appreciate the willingness of City of Renton staff to identify early project issues, and to expedite processing of permit requests. As you know, we hope to begin site work this year. The project 's draft environmental impact statement will be released March 15, 1991. Public hearings will be scheduled for April, 1991. Your January 11, 1991 letter identified two project related issues; the City of Renton aquifer and sewer service to the May Valley-Honey Creek Sierra Heights area. Protection of the Renton's aquifer is important to both the City of Renton and .Metro. On January 23, 1991, Douglas Houck, the Metro project engineer, met with City staff to review the City's short and long term concerns on protecting the aquifer. Metro is currently reviewing the option of relocating the Cedar River Trunk as well as a system to insure that during I-405 construction, sewage will not contaminate the City's aquifer. As part of this effort, a sample of sewage from our trunk line has been collected and is undergoing extensive chemical analysis. The analysis will serve as baseline data for the monitoring program. We are also investigating the feasibility of a joint application with the City of Renton for a Washington Department of Ecology' grant for relocating the sewer line. Currently, our 1992 capital budget recommendation includes a $500, 000 Cedar River trunk project. Following the City of Renton and Metro staff review of alternatives, our budget recommendation may need to be modified to reflect the agreement reached. Hon. Earl Clymer February 13 , 1991 Page Two in response to Renton' s request to serve the May Valley-Honey Creek Sierra Heights area, staff has included the May Creek Interceptor project in our. 1992 capital budget recommendation. The project' s initial scope assumes construction of- 5, 400 feet of 24-inch diameter sewer line and has a planning estimate of $1.7 million. once approved, predesign will begin in late 1991, with the environmental review process in 1992 and construction start in 1993 . Our 1992 budget recommendations will be submitted to the Metro Council on April 15, 1991 with staff briefing for the Council and the Water Quality Committee scheduled in May, 1991. Final approval is expected in June, 1991. The treatment plant expansion is integral to meeting the wastewater treatment needs for the region. The cooperation shown by the City of Renton in support of this regional effort, is greatly appreciated. Sincerely, A'&��� Richard K. Sandaas Executive Director RKS:tfc(20201tr) cc: Mr. John Spencer, Metro CITY OF RENTON ink n cr REivTpN MEMORANDUM ngDept. DATE: January 22 , 1991 TO: City Departments/Divisions See Distribution List FROM: Rubin Yu, Senior Planner Development Planning VL SUBJECT: Metro Renton Treatment Plant Enlargement Notice of Scoping Attached herewith please find a Scoping Notice for the proposed Metro Renton Treatment Plant Enlargement Environmental Impact Statement for you to review and comment. As the Lead Agency, the Municipality of Metropolitan Seattle has just issued a determination of environmental significance for the subject project, in accordance with State Environmental Policy Act (WAC 197-11-360) . The proposed expansion of the plant will increase the capacity from 72 million gallons of sewage a day to about 108 million mgd. The first phase of the project will include on-site landscaping excavation and mitigation activities. Constructing the expansion in phases will allow Metro to use the excavated soils from the site for landscaping, berming, and terracing projects. Metro plans to install landscaping improvements prior to construction of facilities to allow plants to mature while construction projects proceed. The proposed structures are primarily one story and underground facilities consisting of secondary and primary clarifiers to hold waste water. Metro staff has identified the following specific environmental concerns to be addressed in the draft impact statement: . Impact on the Black River blue heron rookery; • Presence of a small wetland on-site; • Impact of neighboring business and commercial development; Appropriate mitigation to address aesthetic impacts (primarily landscaping and odor control) ; . Impacts of construction and operation on water quality in a channel near the plant that carries stormwater to the Green River; Potential noise and odor during operation of the enlarged treatment plant; Temporary construction-related impacts, including increased noise, dust and truck traffic. Please provide me with your comments on the subject matter by January 30, 1991. Thank you. Distribution List: Fire Department Police Department Parks and Recreation Department Building Division Transportation Division Utility Division Long Range Planning cc: Dick Anderson Jay Covington Lynn Guttmann Jim Hanson Don Erickson Mel Wilson cp-l"mnos" "ameTRO Municipality of Metropolitan Seattle Exchange Building • 821 Second Ave. • Seattle, WA 98104-1598 January 17, 1991 PLANNNG DIVISION CRY OF REWON JAN 1 8 1991 Mr. Rubin Yu rtr.%.or-WED Community Development Department City of Renton Municipal Building 200 Mill Avenue South Renton, Washington 98055 Dear Mr. Yu: As we discussed in our recent meeting, Metro has just issued the scoping notice for the treatment plant enlargement project. In your role as coordinator, I would appreciate your assistance in soliciting comments from the City of Renton. Please distribute copies of the scoping notice to those departments with interest in this project and provide me with comments by February 11, 1991. Thank you for your efforts and I look forward to working with you. Sincerely yours, Laurie J. Endlich Senior Environmental Planner LDE:ymg Request for comments Renton Treatment Plant Enlargement Project Public Information/Scoping Document January 1991 0 SEPA Determination of Significance The Municipality of Metropolitan Seattle has issued a determination of environmental significance following the State Environmental Policy Act(WAC 197-11-360).This notice is a request for comments from agencies,citizens and affected Native American tribes on the scope of an environmental impact statement f for the Renton Treatment Plant Enlargement Project.This document describes the project alternatives.The deadline for written comments on potential areas of environmental impact is Monday,Feb. 11, 1991. f You're . two . r Metro has scheduled two open houses on its plan to enlarge the regional sewage treatment plant in Renton at 1200 Monster Road S.W.The ' five-year,$150-million project will increase the planes treatment capacity from 72 million gallons of sewage a e .- day to about 108 mgd. The first open house will be Tuesday,Jan.22,from 5:30-8:30 p.m.in the dining room of the Renton Senior Center,211 Burnett Ave.N., Renton.Drop by to ask Metro staff questions about the project. _ The second open house will be at the plant Saturday, ` Jan.26,from 10 a.m.to 2 p.m. The Renton plant now has eight primary sedimentation tanks,three secondary aeration l During the open house,you tanks, 16 secondary sedimentation tanks and four sludge digesters. i g P Y ' can tour the plant and see 15 minutes and involve 11/4 miles of tunnels and t how Metro treats your sewage and other stairs.Please wear flat shoes.Parents must wastewater.The walking tours take about one hour accompany children under 12. Why is this project needed? Metro needs to enlarge the plant to treat Beginning in 1992,the plant will also be getting increased sewage flows caused by growth in south additional flows from northeast King County. and east King County.Metro completed a Those flows now go to Metro's West Point population and flow study early in 1990 that Treatment Plant in Seattle. projected increased growth in the plant's service In July 1986,the Metro Council adopted a plan area. to upgrade its sewage treatment system to provide Continued on next page &:R7ETR0 lkan water®A Saud lmre ON r federally required secondary treatment.Metro plans to upgrade the West Point plant to provide secondary treatment,and the x plant site does not have room for facilities to treat flows from northeast King County. r Metro plans to divert some of j y those flows to the Renton plant, which already provides secondary treatment,through a Redmond 1 connection pipeline now under construction.Metro also plans to ` r build a North Creek connection �+ ; j' r pipeline from the Woodinville area in the late 1990s or early 2000s. (See map on Page 7.) ` With these increased sewage flows,the Renton plant will exceed its current capacity in the late 1990s. Metro needs to enlarge this plant to treat Increased sewage flows caused by growth in south and east King County. happened Metro has begun a preliminary design study for the project to make sure a thorough technical analysis precedes final design work The study will help Metro make decisions that meet project goals and _ r ensure the project provides new capacity at the minimum total cost. During predesign,a team of consultants headed by Brown and Caldwell consulting engineers will analyze the existing capacity of the plant and pipes leading to and from it. The team will also develop an energy recovery plan,evaluate odor control ; methods and sewage treatment technologies, and identify environmental impacts of the project and measures to reduce those impacts.Brown and Caldwell will complete }` ' the predesign study by July 1991. Metro also expects to begin site preparation in the summer of 1991.Site * ". preparation efforts will consider impacts and mitigation. A major element of impact mitigation will i X, be perimeter landscaping to buffer views of S. the plant from neighboring properties and The plant now has three secondary aeration tanks,each with four 30-by properties on the hillside north of•the plant. 31 7-foot passes. 2 What is Metro planning in Renton? The plant can now provide secondary treatment for 72 million gallons of sewage -` a day.The current project calls for increasing the plant's capacity to about 108 mgd to accommodate sewage flows through the year 2005. Depending on the outcome of the , current predesign study,Metro plans to add primary sedimentation tanks, secondary aeration tanks, secondary sedimentation tanks and perhaps a sludge digester.The plant now has eight primary sedimentation tanks,three secondary aeration tanks,16 secondary sedimentation tanks and four sludge digesters. - The predesign study will determine the The plant now treats sludge In four digesters, each 100 feet in diameter by size and capacity of the new facilities. All 35 feet high. the new facilities would fit within existing plant boundaries. While preparing the site,Metro will begin final Metro intends to begin site preparation in 1991, design for increased capacity and a design for including excavating the site,installing a dewatering system and developing perimeter Continued on next page landscaping. s J it c{ .}R y[• � �t {���Yut The plant now has 16 secondary sedimentation tanks, each 100 feet In diameter. 3 ultimate capacity of the plant.This design effort injection,hot-water heat exchange and submerged will continue into 1992 with major construction combustion.Metro would build new facilities for beginning in 1993. the pasteurization process. Metro is also considering methods for reducing Metro would design the layout of the plant so it pathogens in sludge to below detectable limits.One does not prevent future expansions.Projections way to meet those Class A limits is pasteurization,a suggest that Metro will need 250 mgd of capacity process that requires additional heating before the eventually to treat wastewater from the Renton sludge digestion process. plant service area.Metro has not decided if it During the predesign study,the consultants will would add that capacity to the Renton plant. test three pasteurization methods: direct steam Plant design to include artistic touches Metro's design team for the plant enlargement and site layouts.She will also develop artwork project includes an artist who will work closely proposals for including in the plant design. with engineers and architects.The artist will Metro will present ideas for artistic additions to participate in the development of design criteria the plant as part of the public involvement process. process?What will occur during the environmental Comments received in response to this scoping health and safety,water quality,plants and notice will help Metro staff prepare a draft animals,land use,aesthetics,recreation,traffic, environmental impact statement for this treatment public services and utilities,and energy. plant enlargement project. Metro staff has identified the following specific During the environmental process,Metro will environmental concerns to be addressed in the evaluate the alternatives and potential draft impact statement: environmental impacts of building and operating • impacts on the Black River blue heron rookery this phase of the plant enlargement.The evaluation • presence of a small wetland on-site will also compare the impacts of alternative • impacts on neighboring business and sludge-processing operations on-site and facilities commercial development that may be needed if Metro chooses to produce • appropriate mitigation to address aesthetic Class A sludge at the plant. impacts(primarily landscaping and odor Metro will conduct its environmental review for control) the plant enlargement in two stages.The first will • impacts of construction and operation on water analyze impacts and mitigation for the entire quality in a channel near the plant that carries project,focusing mainly on site preparation and stormwater to the Green River perimeter landscaping. • potential noise and odor during operation of The second stage will provide more detailed the enlarged treatment plant information on specific issues,if necessary.Those • temporary construction-related impacts, issues could include selection of technologies not including increased noise, dust and truck discussed in the earlier review process.This stage traffic. ' will also provide information that becomes Metro will ask citizens to comment on impacts available during final design. and mitigation measures during a comment period J Environmental elements to be evaluated include this spring for the draft environmental impact air quality and odor,earth,noise,environmental statement. Here's some background on the treatment plant Metro designed the plant so it could be enlarged treatment capacity to 36 mgd. Metro completed the in phases to handle regional growth into the 21st latest plant enlargement—doubling its capacity to century.When the plant opened in 1965,it had the 72 mgd—in 1987.The current project is the third capacity to treat 24 million gallons of sewage a day. enlargement of the plant. In 1974,rapid suburban growth in the plant's service area resulted in the first expansion of the Continued on Page 7 4 I I I I i I I FOLD HERE I- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - i I I I I I I I I I I I I I I I I I I FOLD HERE I - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I I NO POSTAGE I NECESSARY I IF MAILED I IN THE I UNITED STATES BUSINESS REPLY MAIL I FIRST CLASS PERMIT NO. 10919 SEATTLE,WA - I POSTAGE WILL BE PAID BY ADDRESSEE FAMETRO s ENVIRONMENTAL COMPLIANCE DIVISION MUNICIPALITY OF METROPOLITAN SEATTLE ATTN GREG BUSH MS 120 821 2ND AVE SEATTLE WA 98104-9986 I I Renton Treatment Plant Enlargement Project Metro is requesting comments from agencies, citizens and Native American tribes on the scope of an environmental impact statement for this project. You may use the space below to identify additional impacts that Metro should address in the draft environmental impact statement. When you finish,please fold this form i so"Business Reply Mail' appears on the outside. Seal and mail the form to Metro by Monday, Feb. 11, 1991. Enclose additional sheets if necessary. I { I - i Please print your name, address and ZIP code in the space below if you want to continue receiving information about this treatment plant enlargement project. Name: Address: City: State: ZIP: - 6 I The plant serves about FUTURE METRO settle,and skimmers remove 341,000 people in a SERVICE AREA floating solids. 140-square-mile area that CHANGES In the plant's secondary j runs south into the Green aeration tanks,effluent from the River drainage basin, now primary sedimentation tanks is north on the east side of ""`; mixed with microorganisms that Lake Washington to iaNO C feed on organic matter Juanita and east to dissolved and suspended in the Redmond and Issaquah, wastewater. Air blown into the The service area includes 1 e tanks serves as an oxygen suburban communities Pry source for and a growing number of p0� The mixture f microorganisms. aand s high-tech industries and microorganisms from the businesses. aeration tanks is separated by The plant uses primary gravity in the plant's secondary and secondary treatment sedimentation tanks,also called to remove 95 percent or clarifiers. more of oxygen- The semisolid material consuming organic matter removed from wastewater in and suspended solids. the sedimentation tanks is called fSecondary treatment sludge.Large tanks called removes about twice the aGEND digesters heat this sludge for amount of toxicants as M W."Poh 5« m kr about 20 days to encourage primary treatment. It also microorganism growth and prevents the effluent from ® s �."'°" activity.Those microorganisms consuming oxygen °°"�°to """ `°°"� break down the organic material important to aquatic life in ® w in the sludge. the receiving water. 0 s.=a Y T,m PW After treatment,the effluent During primary +ty � - TsibN� flows through a 12-mile-long treatment,solid material in '. pipeline to a 580-foot-deep wastewater either settles to outfall about 10,000 feet off the bottom of the planes N Duwamish Head in Puget primary sedimentation A Sound.Metro recycles the tanks or floats to the top. h.. sludge in soil reclamation, Mechanical scrapers landscaping and forestry remove solids that projects. Metro is a municipal corporation governed by a cause.By forming Metro, the communities united federaden of local governments responsible for to work toward a goal that none could reach alone water pollution coniru;and public transportation —clean water. in King County. A 41-member Metro CuLmcil sets The plant in Renton is one of five plants policies for Metro. Councilmembers are 33 local operated by Metro.The four other plants now elected officials,seven representatives appointed provide primary treatment for sewage from the by the King County Council and a chair elected by City of Seattle and north Icing County. Metro is the entire Metro Council. planning to transfer most of the sewage from three Metro serves 34 city and sewer district systems. of those plants to the West Point Treatment Plant. Concerned citizens voted to form Metro in 1958 to Metro is upgrading that plant to provide secondary deal with the deteriorating condition of Puget treatment.Metro plans to close one of the Sound-area water,especially Lake Washington and remaining plants and use the other two to treat Elliott Bay.Inadequate sewage treatment processes only excess combined stormwater and sewage. by cities and small sewer districig were the main 7 Metro wants your comments on potential project impacts Metro encourages citizens,agencies and Native Greg Bush,Manager American tribes to identify additional impacts that Environmental Compliance Division Metro should address in the draft environmental Metro impact statement.You can make comments on the 821 Second Ave.,M.S. 120 enclosed postage-paid mail-back form. Please send Seattle,WA 98104-1598. your comments by Monday,Feb. 11,1991,to: How can citizens get involved in this project? Throughout the project,Metro will hold public Lundt,Metro community relations planner,at meetings to discuss project plans and issues.You 684-1145(or 684-1682 for hearing-impaired persons can attend those meetings to learn more about the using TTY equipment),or send her your name and project and share your views with project staff. address. Other public participation activities include To get more information about the project or to meetings with community and business groups, schedule a speaker for your community or business plant tours and community fairs. group,please call Mary Lundt or write Metro Also,Metro publishes periodic updates on the Community Relations,821 Second Ave.,M.S. 95, project for interested citizens.If you want to be on Seattle,WA 98104-1598. the mailing list to receive these updates, call Mary What is the project schedule? Early Spring 1991—Draft environmental impact statement issued. Late Spring 1991—Final environmental impact statement issued. Mid-1991—Predesign report completed. Fall 1991—Staged construction begins. Winter 1995—New plant facilities begin operation. .171ETA0 FFIRSTSS MAIL Environmental Compliance Division E,WAID 821 Second Ave.,M.S. 120 .959e Seattle,WA 98104-1598 i Renton Treatment Plant Project. Public information/scoping document I Produced by Metro's communications division Printed in the Metro print shop on recycled paper J17WY • Ell 0L TAKEN BY NUMBER, NAME OR SUBDIVISION DATE 'TAKEN BY NUMBER, NAME OR SUBDIVISION DATE 2.0 UPG NO. 52181