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SWP273256
PROJECT REQUEST FORM PLANNING/BUILDING/PUBLIC WORKS DATE: 0 CONTACT: EXT. FILE STATUS ❑ NEW OR 0 EXISTING: FILE CODE(PRim-xxxx): LOCATION ❑ My Work Space: ❑ File Bay Shelf#: ❑ Other: PROJECT NAME/FILE TITLE: E (70 characters max) DE RIPTION CW PROJECT: 2 UTILITY PERMIT# 'JQS O 00 9 LUA# 0,5 WO# 8 7� ADDRESS/STREET NAME(S): Zb4zilt DEV: ; CNTR: ; OWN: / ; CNSLT/ENG: OTHER ALIASES: ✓ Circle Size of Waterline: 8" 10" 12" Circle One: New/Replace/Extension Circle Size of Sewerline: 8" 10" 12" Circle One: New/Replace/Extension Circle Size of Stormline: 12" 18" 24" Circle One New/Replace/Extension CHECK EACH DISCIPLINE INVOLVED IN PROJECT Ltr Drwg . #of sheets M TED (off site improvements) (include TESC) ❑ TRO ❑ ❑ L� (Signalization,Channelization,Lighting) ❑ (sanitary sewer main,include basin name) / (Mains,Valves,Hydrants) (inc.composite&HorizontalCtrl) 9 SWP ❑ ❑ / (CIP onlyxinclude basin name) C� PLR (For Developer Files Only) ❑ getter only) PLEASE CHICLE THE DISCIPLINES WHICH NEED TO SIGN MYLARS WATER WASTEWATER SURFACE WATER TRANSPORTATION FIRE FOR FILE MAINTAINANCE USE ONLY File Codes File Alias Date Entered and Labels Made 6 rif- Z- 30q to �1 ?- ` 5 : — 6 ,e COUGHLIN PORTER LUNDEEN ENGINEERING REPORT Technical Information Report Kennydale Elementary 32 56 May 31,2005 PREPARED FOR: Renton School District#403 1220 No.41h St. Renton,WA 98055 ■ Mr.Rick Stracke PREPARED THROUGH: V McGranahan Architects 2111 Pacific Avenue#100 Tacoma,Washington 98402 p G ST��� g�� Mr.Tom Marshall 31 )05 PREPARED BY: EXPIRES 01/23/2006 COUGHLINPORTERLUNDEEN 413 Pine Street,Suite 300 Seattle,Washington 98101 C� y Phone: (206)343-0460 �. Contact: Mr.Tim Brockway,P.E. JAR b� 1 t1J5 ON TECHNICAL INFORMATION REPORT Kennydale Elementary Coughlin Porter Lundeen Project No.C040055-02 May 31,2005 TABLE OF CONTENTS Section Page I. PROJECT OVERVIEW..........................................................................................................I.............................1 GeneralDescription........................................................................................................................................................1 ExistingConditions.........................................................................................................................................................1 ProposedDrainage System...........................................................................................................................................2 II. CONDITIONS AND REQUIREMENTS SUMMARY...................................................................................2 King County Surface Water Management Design Manual Core Requirements:.................................................2 SpecialRequirements:....................................................................................................................................................3 ProjectSpecific Requirements:......................................................................................................................................4 III. OFF-SITE ANALYSIS..........................................................................................................................................4 Task 1-Study Area Definition and Maps..................................................................................................................4 Task2-Resource Review..............................................................................................................................................4 Task3-Field Investigation............................................................................................................................................4 Task 4-Drainage System Description and Problem Screening..............................................................................4 IV. SITE HYDROLOGY.............................................................................................................................................7 PartA-Existing Site Hydrology..................................................................................................................................7 PartB-Developed Site Hydrology..............................................................................................................................8 PartsC and D-Hydraulic Analysis.............................................................................................................................9 PartE-Water Quality..................................................................................................................................................10 ■ Standard Requirements...............................................................................................................................................10 V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN...............................................................................12 Standard Requirements(based on KCSWDM .......................................................12 On-site Conveyance......................................................................................................................................................12 VI. SPECIAL REPORTS AND STUDIES..............................................................................................................13 VII. BASIN AND COMMUNITY PLAN AREAS................................................................................................13 SBasin Plan(1.3.4-1)........................................................................................................................................................13 CommunityPlan(1.3.4-1)............................................................................................................................................13 VIII. OTHER PERMITS..............................................................................................................................................13 IX. EROSION AND SEDIMENTATION CONTROL DESIGN........................................................................13 StandardRequirements...............................................................................................................................................13 X. BONDS.................................................................................................................................................................14 XI. MAINTENANCE AND OPERATIONS MANUAL....................................................................................15 StandardMaintenance.................................................................................................................................................15 CO UG H LI N PORTERLU N D E EN Kennydale Elementary School i Renton,Washington LIST OF FIGURES ■ FIGURE Figure 1-Vicinity Map Figure 2-Existing Site Drainage Map Figure 3-Proposed Drainage System Figure 4-Wetland Map Figure 5-Seismic Hazards Area Map Figure 6-Streams and 100 yr Flood Plains Map Figure 7-Landslide Hazards Area Map Figure 8-Erosion Hazard Area Map LIST OF TABLES Table 1-Existing Site Conditions Area Breakdown.....................................................................................................8 Table 2-Developed Site Conditions Area Breakdown................................................................................................9 Table3-Summary of Detention Vault............................................................................................................................9 Table4-Summary of Detention Pond..........................................................................................................................10 Table 4-Summary of Water Quality Biofiltration System.........................................................................................11 Table 5-Swrtmary of Water Quality Vault System....................................................................................................11 Table 6-Summary of Water Quality Pond..................................................................................................................11 APPENDICES Appendix A Figures Appendix B Supporting calculations • Detention • Water Quality • Conveyance Analysis Appendix C Geotechnical Report Appendix D Operations and Maintenance Manual COUGHLINPORTERLUNDEEN Kennydale Elementary School ii Renton,Washington I. PROJECT OVERVIEW General Description The following Technical Information Report(TIR)provides the technical information and design analysis required for developing the Drainage Plan and Temporary Erosion and Sedimentation Control Plan(TESC) for Kennydale Elementary School. The design for Kennydale Elementary was based on the requirements set forth in the 1998 King County Surface Water Design Manual(KCSWDM). Kennydale Elementary School is located at 1700 NE 28th Street in Renton,Washington(see Figure 1- Vicinihj Map and Figure 2-Area Map). The school is in Renton,King County in Section SW 32,Townsltip 24N,Range 5E,Willamette Meridian,and is located within the Lake Washington and May Creek Drainage Basins. The existing school consists of two buildings,surrounded by parking to south,paved play areas to the north and east,and play fields on the northern portion of the site. The terrain is fairly flat,falling generally north and east. The Renton School District is proposing the removal of the existing Kennydale Elementary School and related utilities followed by the construction of an entirely new school within this site,along with associated parking,infrastructure. The existing structure will not remain operational during the construction project. The District is proposing to construct a new two-story elementary school along with associated parking lots, bus loading areas,hardscape play,and a service yard. The existing play field will not be altered as part of this project. The total developed site area for the project is approximately 6.6 acres. The proposed building has a footprint of approximately 37,500 square feet. The new building,parking areas and site improvements will add approximately 26,600 square feet of impervious area to the site. The drainage basin split on the project site necessitates the design of two separate stormwater conveyance, treatment,and storage systems. Stormwater runoff within the Lake Washington Basin will sheet flow to a combined water quality and detention pond at the south west corner of the site. Two separate water quality systems will be constructed for the May Creek Basin. The storm water runoff from the southeast parking lot . will be routed to a biofiltration swale at the southeast corner of the site. Stormwater from the northwest service yard will be routed to a water quality vault to the north. Both of these systems,and the remainder of the collected runoff from the May Creek portion of the site,will be routed to a single detention vault. The roof downspouts will bypass the water quality vault and discharge directly to the detention vault. The discharge point for the May Creek Basin will an existing catch basin located in Kennewick Place NE. Existing Conditions The existing Kennydale Elementary School occupies approximately 6.64 acres and consists of the elementary school and associated structures,playfields,and impervious parking lots and play areas. There are presently no stormwater detention or water quality facilities on the site. The project is located along a localized egeographic divide,which separates the property into two drainage basins,both of which ultimately drain to Lake Washington through different routes. The western portion of the site,approximately 1.2 acres,drains west,across I-405 and along surface streets west of the freeway and then ultimately down a ravine which drains below Lake Washington Boulevard,the Gene Coulon Park property and then enters Lake COUGHLIN PORTER LUNDEEN Kenirydale Elementary School 1 Renton,Washington Washington. The eastern and northern portion of the site,approximately 5.5 acres,drains north,through the existing school site,across Kennewick Place NE and then through a tight line system owned by the City of Renton that discharges to May Creek. (See Existing Site Drainage Map). rProposed Drainage System The proposed Kennydale Elementary School will consist of the building,parking lots,and hardscape play areas. Drainage improvements will include curbs and catch basins on-site to direct flows to either the Lake Washington Drainage Basin or the May Creek Drainage Basin. For the west basin,flow control per City Standards and the KCSWDM will be provided in an open detention pond. The pond will also provide the required water quality treatment,having the water quality pond storage provided below the detention. This portion of the pond will have water in it at all times,although some water depth fluctuation may occur during dry periods. The athletic field area of the eastern portion of the site will remain undisturbed. The remainder of this basin which contains the buildings,the hardscape play and the parent(east)drop off parking lot will flow first to a biofiltration swale,and then into the detention vault located beneath the hardscape play area. The service yard area north of the school building will have its own water quality storage vault for treatment. Following the treatment and detention all flows from the developed portion of the eastern basin will be released at allowable flow levels into the existing conveyance system in Kennewick Place NE. The detention vault has been sized to meet all of the requirements of the KCSWDM Section 3.3.2 Level 2 flow control. The flow duration frequencies discharging from the detention facility will be at or below the peak flow rates of the existing basin for all storm events modeled between and including one-half of the two- year storm and up to the 50-year storm. II. CONDITIONS AND REQUIREMENTS SUMMARY r This section will address the requirements set forth by the Core and Special Requirements listed in Chapter 1 of the KCSWDM. King County Surface Water Management Design Manual Core Requirements: 1. Discharge at a natural location(1.2.1): The existing and proposed discharge points are concurrent. Developed flows from the Lake Washington Drainage Basin will be conveyed to the existing storm system to the west across 1-405. Developed flows from the May Creek Drainage Basin will be conveyed to the existing catch basin located in Kennewick Place NE. Please refer to Appendix B for this information. 2. Off-site Analysis(1.2.2): This subject is covered in Sections III and IV. A Level 1 downstream analysis has been performed. 3. Flow Control(1.2.3): COUGHLIN PORTER LUNDEEN Kennydale Elementary School 2 Renton,Washington r One detention vault,designed per the Stream Erosion protection(Level 2)standard,will provide flow control for the May Creek Drainage Basin. One detention pond,designed per the 1990 King County SBUH standard,will provide flow control for the East Lake Washington Drainage Basin. This subject is addressed in Section IV. 4. Conveyance Facilities(1.2.4): This information and calculations are presented in Section V. Closed pipe systems and one biofiltration Swale have been provided for on-site stormwater conveyance. 5. Temporary Erosion/Sedimentation Control(1.2.5): The project will construct a series of sediment controls to address the specific conditions at the site. Further detail is presented in Section IX. r6. Maintenance and Operation(1.2.6): The proposed storm drainage system will be owned,operated and maintained by the owner. A maintenance and operation manual can be found in Section XI of this report. (not included at this tune) 7. Financial Guarantees atui Liability(1.2.7): The owner and contractor will obtain all necessary permits prior to the beginning of construction. The owner will be responsible for required bonds. 8. Water Quality(1.2.8): This project will provide one water quality biofiltration swale,one water quality vault,and one water quality wet pond on the site,designed in accordance with the KCSWDM. r Special Requirements: Special Requirement#1. Other Adopted Area-Specific Requirements Section 1.3.1 • Critical Drainage Areas(CDAs):Not Applicable • Master Drainage Plans(MDPs):There are no known master drainage plans covering this project site: • Basin Plans(BPs):The project is located within the May Creek Basin Plan and the East Lake Washington Basin Plan. There are no area specific drainage review thresholds for this area. • Lake Management Plans(LMPs):Not Applicable • Shared Facility Drainage Plans(SFDPs):Not Applicable Special Requirement#2. Floodplain/Floodway Delineation,Section 1.3.2: This project is not within a designated flood plain. Special Requirement#3. Flood Protection Facilities,Section 1.3.3: Not Applicable rSpecial Requirement#4. Source Control,Section 1.34: A modern,covered and solid bottomed(no leaks)garbage dumpster will be provided by the City's solid waste provider to this site. Renton School District will coordinate with the provider to emphasize the need for properly covered and sealed dumpsters for use on the site. Special Requirement#5. Oil Control: COUGHLIN PORTER LUNDEEN Kemydale Elementary School 3 Renton,Washington Traffic is anticipated in this area. One biofiltration swale one water quality vault,and one water quality wet pond are being provided for water quality and will adequately treat all runoff as required by the KCSWDM for oil and any other naturally occurring pollutants. Project Specific Requirements: There are no project specific requirements. III. OFF-SITE ANALYSIS Task 1 - Study Area Definition and Maps See Figure 2 for drainage sub-basins,discharge points from the site and other related information. Task 2 -Resource Review a) Adopted Basin Plans May Creek Basin does not have an adopted basin plan East Lake Washington Basin-none b) Basin Reconnaissance Summary Reports: See Attached appendices c) Critical.Drainage Area Maps: Not in critical Drainage areas. d) Floodplain/floodway(FEMA)Maps: Site not in 100-yr Floodplain e) King County Soils Survey: Soils information has been included. f) Wetland Inventory Maps: See`Sensitive Areas Folio'. g) Sensitive Areas Folio: Site is not within any sensitive areas. Task 3 -Field Investigation A site visit has been made to the project site to gather information including a Level 1 Downstream Analysis. Please refer to the discussion below. Task 4 -Drainage System Description and Problem Screening Upstream Drainage Review The Kennydale School site is located near the high point of the surrounding terrain. The NE 30f Street and Kennewick Place NE grades are lower than the site to the north and east. I-405 is also lower than the site to the west. To the south the ground is higher than the Kennydale site,but flows from this direction enter the conveyance system in NE 28th Street and are conveyed west as described below. No upstream flows therefore enter the school property. COUGHLIN PORTER LUNDEEN Kennydale Elementary School 4 Renton,Waslungton Level 1 Downstream Drainage Review North drainage: On July 21st 2004 the following observations were made while researching the downstream drainage towards the north of Kennydale Elementary School. The weather was good and the temperature was approximately 85 F. The exploration started at about 1:30 and ended around 5:30. We began our field investigation at the downstream end of the eastern basin,north of Kennydale Elementary approximately a quarter mile,near May Creek and Jones Road. After reviewing City records it was assumed that there were two drainage pipes in the ravine that discharge flows from Kennewick Place NE into the creek below. After crossing to the south side of May creek we began following the drainage course upstream. At the point of our crossing,the Creek has built up a sediment and rock bar and turns to flow more easterly,towards Jones Road before turning west again,parallel to the road. This sedunent bar is likely a result of the bend in the Creek causing the sediment to fall out. This bar did not appear to be deposited from any side channel and there was no side channel present in this vicinity. The lower discharge of the drainage course into May Creek occurs approximately 50 yards downstream of where we first crossed May Creek. At this point the flows were approximately 1 to 2 inches deep and 18 to 24 inches wide,flowing clear and steady. This side channel from the ravine discharges through the bank of May Creek through dense vegetation. No sediment plume or sediment bar development was visible in May Creek at this point. This area upland of May Creek is very broad and flat,and it took some effort to locate the actual drainage course. We continued upstream,to where the ravine begins and the drainage course is more defined and constrained in this steeper terrain. Flows were consistent with those seen below,and were approximately 1 to 2 inches deep,12 to 18 inches wide and steadily flowing. The channel here was cobbled on the bottom, with no visible evidence of instability or incising. We were unable to get close to the western drainage pipe that apparently was the former discharge from Kennewick Place. The vegetative growth surrounding May creek and the ravine was thick and well established. Traversing the ravine was difficult due to the thick vegetation and steep slopes. Along the base of the ravine and approximately 10 yards past a large tree fall it was impossible to maneuver as the area was approximately 2-feet deep highly organic wet soil(dark brown,silty)surrounded by extremely steep slopes. From this point it was impossible to continue further upstream. This bar of organic material may have migrated down the ravine from the apparently former culvert discharge from Kennewick Place. The dark color and fine texture of this sediment resembled urban roadway sediment accumulation and not channel sediments from erosion. The discharge pipe was not able to be located from the bottom of the ravine but appeared from the City drainage map to be approximately 50 feet further upstream,and several feet above the floor of the ravine. Along this reconnaissance no undercutting or incision was visible in the channel. Minor migration of sediment was visible as would be expected from a native channel in steep terrain transitioning to flat. We then attempted to find the discharging runoff in the ravine was from the top of the ravine just off of Kennewick Place NE. The President of the homeowner's association for the townhouses above the ravine provided us with some background of the system in the area and was aware of a 24-inch CMP that discharged flow onto a bed of rocks in the ravine. The CMP was located and appeared to be the previous main discharge into the ravine and down toward May creek. From along the condominium property edge another attempt to locate the pipes was made. We traversed down the slope but again the slopes were too steep to get down to the point of the culvert and the thick vegetation hid the ground causing unsure footing. The pipe was never located from above the ravine. Following this field walk and after further investigation with City records staff,we were able to determine that a flow sputter or diversion structure was added upstream of the former ravine discharge point,with a COUGHLIN PORTER LUNDEEN Kennydale Elementary School 5 Renton,Washington pipe running down the side of the hill above May Creek and discharging at the base. We did not encounter this pipe in our investigation,however it appears that this was a City installed diversion in order to likely improve stability in the ravine and prevent erosion that the former culvert likely caused due to its position high above the base of the ravine and the steepness of the ravine itself. West drainage: August 6th 2004 the weather was in the low 70's and it was raining all morning long. Arrival onto the site was at 1:30 and ended at 4:00. It rained periodically during the site visit. The runoff in the Kennydale Elementary School's western basin crosses in a 12 inch pipe beneath I-405 and then enters the City street conveyance system west of the freeway. City records show the pipe beneath the freeway entering the conveyance system in NE 28th Street near Meadow Avenue North. West of this point, the piped roadway system discharges into the upper portion of a ravine at the vicinity of Meadow Place North. It is unclear from City maps,but the flows appear to continue further west,perhaps from a flow- splitter to the corner of Park Avenue and NE 28th. From this location,the ravine was inaccessible due to the overgrown vegetation in the ravine. Further downstream on 261h Street,in a recently developed area,a bridge or very large box culvert crosses the ravine and stream. Again the entire area is overgrown with vegetation and the creek was inaccessible. The creek was visible on the upstream side of the bridge,and there were no apparent signs of sediment deposit,indicating apparent stability upstream of this point. No erosion or incision was visible at this location either,and the large culvert clearly has sufficient capacity for any anticipated flows. The bank leading down to the ravine all along its sides is very steep,roughly a 1/2:1 or steeper slope and in some flatter places a 1:1 slope. There is silt fence on the north and south sides of the road near the bridge,apparently for the ongoing construction in the development. The decision was made to approach the ravine from below wherever access could be found,find any other constrictions or culverts and assess the ravine for stability at these locations. Upstream from Lake Washington Blvd at the ravine crossing there is a large culvert which was covered with dense blackberries and was inaccessible. Along the north side of this ravine is a utility access road, extending a few hundred feet upstream along the base of the north slope of the ravine. Roughly 300 feet from Lake Washington Blvd we located a 48"CMP culvert. No signs of erosion or bank cutting were present and there was little sign of sediment accumulation no sign of significant flooding in the area above the culvert. There is currently silt fence along the north bank of the creek,associated with the house construction and utility installation occurring to the north. There were also signs of recent track-hoe work in the area. Upstream of this culvert there was approximately 50 feet of visible channel that was well established, ■ approximately 2 to 3 feet wide and appeared stable and clean along the channel bottom. No incision or evidence of instability was observed. Due to vegetation on both sides of Lake Washington Blvd,both the downstream end of the road culvert and the upstream end of the railroad culvert were inaccessible. On the downstream side of Lake Washington Blvd,on the west side of the railroad tracks we were able to locate a 24"concrete culvert. The flow at this tlocation was approximately 2-3"deep and 18-24"wide. No scouring or undercutting below or around the culvert was present. Below this culvert the flow crosses into Gene Coulon Park,in an area of trees and grasses,and widens to approximately 4 to 5 feet. Minor evidence of streambed gravels being pushed around by peak flows was present,but no visible signs of instability were noted. Flows then continue to widen, reaching over 8 feet wide as they cross beneath the Park walkway at a wooden elevated walkway,through dense canary grasses. Further downstream approximately 30 to 50 feet the runoff reaches the edge of Lake Washington. At this location there is a very stable sand bar from deposits carried downstream and no other signs of instability or erosion at the shoreline itself. It appears that a series of logs has been anchored at this point to perhaps cause the sediment to fall out through the stilling of flows before they enter the lake. The sand bar appeared to have been there for some time and did not appear to be recently developed,as it did COUGHLIN PORTER LUNDEEN Kennydale Elementary School 6 Renton,Washington not settle under weight and was very compact. It is possible however that this is the result of wave action from the Lake. IV. SITE HYDROLOGY This section describes the conditions that contribute to the storm water runoff values and mitigation efforts proposed for the site. Part A- Existing Site Hydrology The existing site hydrology consists of an existing school and associated improvements. There are existing established storm water runoff conveyance lines,however,there are no control or water quality treatment facilities on the site. The total site area is 6.64 acres. The existing site conditions are shown in the attached Existing Site exhibit,from a documented field survey. The site occurs on a natural topographical ridge, which separates the property into two drainage basins,both of which ultimately drain to Lake Washington through different routes. The western portion of the site,approximately 1.2 acres,drains west,across I-405 and along surface streets west of the freeway and then ultimately down a ravine which drains below Lake Washington Boulevard,the Gene Coulon Park property and then enters Lake Washington. The eastern and northern portion of the site,approximately 5.5 acres,drains north,through the existing school site,across Kennewick Place NE and then through a tight line system owned by the City of Renton that discharges just above and to May Creek. The May Creek portion of the site contains an existing play field that will remain undisturbed during this project and therefore will not be accounted for in the detention and water quality system design and analysis,as shown in the Developed Site exhibit. The field contains approximately 1.84 acres. The disturbed portion of the May Creek Basin is 3.6 acres. A small portion of the East Lake Washington Drainage Basin will not be developed in this project so that portion will not be accounted for in water quality and detention calculations,as shown in the Developed Site exhibit. The existing site conditions are summarized in Table 1 below. COUGHLIN PORTER LUNDEEN Kennydale Elementary School 7 Renton,Washington Table 1-Existing Site Conditions Area Breakdown Drainage Basin Land Cover Area(acres) Description Lake Washington Impervious Area 0.848 Parking lots,concrete walks Pervious Area 0.039 Landscaping Total 0.89 May Creek Impervious Area 1.93 Buildings,parking lots,hardscape play Pervious Area 1.67 Landscaping,athletic fields Total 3.60 Total Disturbed Site 4.49 Field Basin Total 1.84 Athletic Fields,concrete walks Undisturbed Lake Washington Total 0.31 Grass,concrete walks Total Site 6.64 Existing Kennydale Elementary Site Part B -Developed Site Hydrology The existing basin split on site will be maintained to the greatest extent possible. Where grading on the proposed site does not allow certain areas to drain to their respective basin,an equivalent area basin swap will be made. A comparison of Table 1 and Table 2 will reveal that the developed condition provides a �l reduction of the impervious area within the East Lake Washington Drainage Basin. However,due to the proposed grading and drainage system on the site,an equivalent area swap could not be entirely preserved. The proposed system will add approximately 0.33 acres to the East Lake Washington Drainage Basin. This added area is not included in the allowable discharge calculations,however. This will ensure that although a nunor basin transfer is proposed,discharging stormwater runoff rates will remain less than or equal to the existing allowable release rates,consistent with the 1990 SBUH KCSWDM detention standard. The currently developed athletic fields in the May Creek basin at the north end of the Kennydale school site and a small portion of the East Lake Washington Drainage Basin along the freeway wall will not be developed in this project so those portions of the site will not be accounted for in water quality and detention calculations. Please refer to the Developed Site exhibit for this information. The developed site conditions are summarized in Table 2 below. COUGHLIN PORTER LUNDEEN Kennydale Elementary School 8 Renton,Washington Table 2-Developed Site Conditions Area Breakdown iDrainage Basin Land Cover Area(acres) Description Lake Washington Impervious Area 1.01 Parking lots,concrete walks Pervious Area 0.21 Landscaping Total 1.22 May Creek Impervious Area 2.38 Buildings,parking lots,hardscape play Pervious Area 0.89 Landscaping,athletic fields Total 3.27 Total Disturbed Site 4.49 Field Basin Total 1.84 Existing athletic Fields,concrete walks Undisturbed Lake Washington Total 0.31 Grass,concrete walks Total Site 6.64 Existing Kenn dale Elementary Site Parts C and D -Hydraulic Analysis The proposed drainage systems for the new developed condition of the site will consist of sheet flow across asphalt parking to a water quality/ detention pond and a conveyance system,a biofiltration swale,a water quality pipe,and one detention vault. The detention vault is centrally located on the eastern side of the site. The vault has the capacity to detain 11,000 cubic feet of stormwater runoff. The storm water detention vault has been designed and analyzed per the King County Runoff Time Series Level 2 Flow Control standard as required in the May Creek basin. A Level 2 facility is designed to release stormwater runoff generated from developed site conditions at durations that do not exceed the durations from one-half of the two-year and up to the 50-year storms under the existing site conditions,per the 1998 KCSWDM. A summary of the detention facility is shown in Table 3 below. Table 3-Summan of Detention Vault Prop.Detention Vault Value Live Storage Depth 5.0 feet Bottom Elevation 230.25 Max W.S.Elev.* 235.17 Overflow Elevation** 235.75 Volume Provided* 11,000 cf *Maximum water surface elevation during100-year overflow Level 2 event. **Maximum overflow water surface elevation assuming all orifices are plugged. COUGHLIN PORTER LUNDEEN Kennydale Elementary School 9 Renton,Washington The combined stormwater water quality/detention pond in the East Lake Washington basin has been designed and analyzed per the 1990 King County Manual-SBUH method matching the developed 2,10, and 100 year peaks with the existing respective return period peaks and allowing for a 30% factor of safety. The intent is to protect flow carrying capacity and limit erosion within the downstream conveyance system. A summary of the detention facility is shown in Table 4 below. Due to the small size and nature of the development in the East Lake Washington Drainage Basin,the size of the detention pond is controlled by the volume necessary for the water quality storage. The live storage(detention)provided in the pond is oversized for this development. Table 4-Summari of Detention Pond Prop.Detention Pond Value Live Storage Depth 1.25 feet Bottom Elevation 234.75 Max W.S.Elev.* 235.97 Overflow Elevation** 236.00 Volume Required 1009.0 cf Volume Provided* 4135.0 cf *Maximum water surface elevation during maximum Level 1 event-100-yr. **Maximum overflow water surface elevation assuming all orifices are plugged. Part E- Water Quality Standard Requirements There are three levels of water quality facilities defined in the 1998 Surface Water Design Manual in the Water Quality Applications Map. These levels are as follows: 1. Basic Water Quality Treatment Areas 2. Sensitive Lake Treatment Areas 3. Regionally Significant Stream Reach Treatment Areas This project will provide water quality in accordance with basic water quality requirements of the KCSWDM (section 6.5.5.2).The access drives and parking lots will be subject to vehicular traffic and will therefore require basic water quality treatment. Water quality will be provided through one biofiltration swale and one water quality vault. In order to allow the use of a biofiltration swale on the heavily constrained site it was necessary to limit its size. To achieve this,the non-pollution generating surfaces of the hardscape play areas and fire access drive(gated,low use)are routed directly to the detention vault,bypassing the biofiltration swale. A portion of the building roof area is also routed through the biofiltration swale to avoid the expense of routing the roof runoff around the building in a separate conveyance system. The swale has been sized according to the areas summary listed in Table 4 below. COUGHLIN PORTER LUNDEEN Kennydale Elementary School 10 Renton,Washington Table 4-Summanj of Water Qualihj Biofiltration System Water Quality System Biofiltration Swale Pervious Area 0.45 acres Impervious Area 0.66 acres Roof Area 0.25 acres Total Area 1.36 acres Water Quality Flow 0.259 cfs The water quality vault has been designed to treat the stormwater runoff from the service area on the north side of the proposed school building. The required water quality volume was determined from basic wet pond sizing and an equivalent volume was used to size the wet vault. 12 inches of sediment storage will be provided in the vault. See Table 5 below for water quality vault information. Table 5-Summant of Water Quality Vault System Water Quality System WQ Vault Pervious Area 0 acres Impervious Area 0.337 acres Total Area 0.337 acres Required W/Q volume 1,552 CF Provided W/Q volume 1,575 CF Vault Storage Dimensions 4.5'H x 35'L x 10'W WQ Depth 4.5 feet The dead storage volume in the combination water quality/ detention pond has been sized per the basic pond requirements in King County. The pond will consist of one cell with one foot of sediment storage provided. Pond side slopes will be 2.5:1. The length to width ratio at mid depth will exceed the 3 to 1 length to width ratio required in the drainage code. Per Figure 6.4.113 in KCSWDM,an internal berm is not required for ponds with a length to width ratio greater than 4:1. The Kennydale water quality pond has a mid depth length to width ratio of approximately 5:1,and therefore,a berm will not be provided. The pond as designed is relatively small by KCSWDM standards. The surface area of the bottom of the pond is less than the threshold of 1500 sf,and therefore does not require ramp access to the bottom of the pond. (1998 SWDM ch.5.3.1-Access Requirements p.5-21)Also,this pond could be considered a small deep pond in which the trackhoe could park on the pond slope to remove sediment. A ramp would not be required in this situation. The wet pond sizing calculations can be seen in Appendix B. A summary of the water quality pond is provided in Table 6 below. Table 6-Summary of Water Quality Pond Water Quality System WQ Pond Pervious Area 0.21 acres Impervious Area 1.01 acres Required W/Q volume 4,930 CF Provided W/Q volume 7620.CF Pond Cell Top Dimensions 105 feet x 29 feet WQ Depth 4 feet COUGHLIN PORTER LUNDEEN Kennydale Elementary School 11 Renton,Washington f V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN This section discusses the criteria that will be used to analyze and design the proposed storm conveyance system. Standard Requirements (based on KCSWDM): 1. Facilities must convey the 100-year flow without overtopping the crown of the roadway,flooding buildings,and if sheet flow occurs it must pass through a drainage easement. The detention facilities have been designed to convey the 100-year developed flow or direct overflows away from buildings and within street gutters capable of handling the flow. 2. New pipe systems and culverts must convey the 25-year flow with at least 0.5 feet of freeboard. (1.2.4-1). The conveyance systems have been designed to convey the 25-year flow with at least 0.5 feet of freeboard. Calculations are included in Appendix B. 3. Bridges must convey the 100-y ear ow and provide a minimum o two feet,varying a to six feet,o g J J fl P f J g P f f clearance based on 25%of the mean channel width. (1.2.4-2)(4.3.5-6. N/A. This project does not propose a bridge. 4. Drainage ditches must convey the 25-year flow with 0.5 feet of freeboard and the 100-year flow without overtopping. (1.2.4-2). There are no drainage ditches for this proposed development or u1 the proposed frontage improvements. 5. Floodplain Crossings must not increase the base flood elevation by more than 0.01 feet[41(83.0]and shall not reduce the flood storage volume[37(82.A)]. Piers shall not be constructed in the FEMA floodway. [41(83.F.1)]. There are no floodplain crossings associated with the construction of this project. 6. Stream Crossings shall require a bridge for class 1 streams that does not disturb or banks. For type 2 and type 3 steams,open bottom culverts or other method may be used that will not harm the stream or inhibit fish passage.[60(95.B)]. There are no stream crossings associated with the construction of this project. 7. Discharge at natural location is required and produce no significant impacts to the downstream properhj(1.2.1-1). The project will discharge to the existing discharge location. A map showing the specific existing discharge location is included in Appendix B(Figure 131 on page B49),along with calculations proving that the proposed discharge location will not worsen any existing conveyance problems that may exist downstream from the site. A minor shift from the May Creek basin to the East Lake Washington basin of less than 0.5 acres is requested. Detention and release rates,however,are sized to match those from the original basin size,not the increased basin. On-site Conveyance The on-site conveyance system will consist of Type 1 and Type 2 catch basins,six,eight and 12-inch conveyance lines,one biofiltration swale,a stormwater detention pond,and a stormwater detention vault. The capacity of the on-site lines was evaluated using the Rational Method and a Manning's-based COUGHLIN PORTER LUNDEEN Kennydale Elementary School 12 Renton,Washington conveyance spreadsheet. If pipe capacity is questionable,energy grade elevation will be evaluated using the Direct Step Backwater Method. The conveyance system has been designed to provide adequate slopes and sizes. Refer to Appendix B for conveyance calculations. Outfalls Energy dissipation is required for all outfalls,rock erosion protection at a ininimum. (1.2.3-3).The conveyance system proposed will discharge directly to the public storm system where energy dissipation will not be provided. The biofiltration swale will be provided with rock armor at all outfalls from pipes. VI. SPECIAL REPORTS AND STUDIES 1. No special reports included. VII. BASIN AND COMMUNITY PLAN AREAS Basin Plan(1.3.4-1) There are no basin plans that will impact this site. Community Plan(1.3.4-1) There are no community plans that will impact this site. VIII. OTHER PERMITS AnNPDES permit will be required for this project. DC. EROSION AND SEDIMENTATION CONTROL DESIGN This section lists the requirements that will be used when designing the Temporary Erosion and Sedimentation Control plan(TESC plan)for this site. Standard Requirements COUGHLIN PORTER LUNDEEN Kennydale Elementary School 13 Renton,Washington Erosion/Sedimentation Plan shall include the following: 1. Facilities required include:stabilized constniction entrance,sedimentation pond, interceptor swales, filter fabric fencing. (1.2.5-1).The project will provide two construction entrance/exits,truck wheel washes,filter fabric fencing,a sediment pond,slope stabilization,catch basin protection and interceptor swales. 2. Timing-For the period between November 1 through March 1 disturbed areas greater than 5,000 square feet left undisturbed for more than 12 hours must be covered with mulch,sodding,or plastic covering. A constncction phasing plan shall be provided to ensure that erosion control measures are installed prior to clearing and grading. (1.2.5-1).Notes addressing each of these items have been placed on the civil engineering plans. 3. Planning-Plan shall limit tributary drainage to an area to be cleared and graded. Delineate distension, stake and flag clearing limits(1.2.5-1). The clearing limits have been indicated on the TESC plan. Notes addressing this item have been placed on the civil engineering plans. 4. Re-vegetation-Re-vegetate areas to be cleared as soon as practicable after grading. (1.2.5-1). Notes addressing this item have been placed on the civil engineering plans. The TESC plan for this project has been designed to protect off-site properties as well as to minimize the quantity of sediment-laden water that enters the public storm system. The following BMP's will be included on the TESC plan for this project. • Clearly delineated clearing limits staked prior to any construction activity. • Stabilized construction entrances with a wheel washing station for trucks exiting the site. All material that is tracked off the site will be cleaned by sweeping. • Catch basin protection will be used on all existing and future catch basins as they are nnstalled, to reduce the amount of sediment that can enter the storm system. • Cover measures will be implemented for disturbed areas greater than 5,000 square feet in accordance with the King County standards. • Temporary sediment ponds will be included to allow the opportunity for sediment to settle out of onsite runoff prior to discharging from the site. The ponds will be excavated at the locations of the final permanent storm water ponds,per Appendix D.4.5.s of the KCSWDM. The sedimentation pond surface will be sized based on the 2-year flows from the graded site,and will comfortably fit within the limits of the permanent ponds. This will allow final excavation at project close to be minimized. All construction debris will be promptly removed from the site to minimize demolition and construction impacts to the site. The contractor will implement additional BMP's as required or recommended by the City of Newcastle inspectors or other agencies as required. This will help prevent demolition and construction debris,waste material,fuel,oil,lubricants and other fluids from entering the public storm system. These measures are shown on the TESC plan sheets shown in the drawings set. X. BONDS Bond Quantity Worksheets Bond quantity worksheets are not included in this report. COUGHLIN PORTER LUNDEEN Kennydale Elementaiy School 14 Renton,Washington XI. MAINTENANCE AND OPERATIONS MANUAL Standard Maintenance Per standards set forth in the King County Surface Water Design Manual,the owner will maintain facilities. Sections of the King County Storm Water Management Design Manual outlining the Operations and Maintenance of these facilities will be included in Appendix D. ■ COUGHLIN PORTER LUNDEEN Kennydale Elementary School 15 Renton,Washington Appendix y 7 D v a X D APPENDIX A Figure 1-Site Area Map Figure 2-Existing Site Drainage Map Figure 3-Proposed Drainage System Figure 4- Wetland Map Figure 5- Seismic Hazards Area Map Figure 6-Streams and 100 yr Flood Plains Map Figure 7-Landslide Hazards Area Map Figure 8-Erosion Hazard Area Map COUGHLIN PORTER LUNDEEN Keruiydale Elementary School 16 Renton,Washington COUGHLIN PORTERLUNDEEN A CONSULTING STRUCTURAL AND CIVIL ENGINEERING CORPORATION M , `mAPQIJ Pt � p 204m N 36thI_t 600 ft b�.. Se 89,.1 .. _ N 35th St Ne'34th PI N 34m St I r � N ^3fd St 90th 5t a E �Kerrryc#ale_ 3 � ' S y� _Q N 32nd St z . N 3 t st St N 30th St N 29th St alllu 4� Ne 2e t j N 27th PI Ne 271h Ct w { --Ni 26th P1 i N 26th S� MRArlo !1m I Ne 25th PI a p „11 i E " ' N 24th St Ne 24th St y' 1 Y� _ � _ �- P� , � . ;z 1 � t co eb CD to o � CD 200A'Rita Qcle8#.com'Inc.'.0 2004 VTEQ z 11 caZ C cc N O dC_ S o O O O N s Figure - Site Area Map .Q 0 U PROJECT: Kennydale Elementary School DESIGNED BY: sas DATE: 12-09-04 _ PROJECT NO, C040055-02 CLIENT: Renton School District CHECKED BY: tbb SHEET OF 413 PINE STREET-SUITE 300 SEATTLE,WA 98101 P: 206/343-0460 F: 206/343-5691 COUGHLIN PORTERLUNDEEN A CONSULTING STRUCTURAL AND CIVIL ENGINEERING CORPORATION Undeveloped Lake Wa Basin Field Basin ),vH Pervious 0.28 Acres Total 80104.0 sf mperv' 3 4, —1Acres Pervious 1.75 Acres ti N V938*W Impervious 0.086 Acres .0 234 Ex Lake Wa Basin(for design) 0 25 50 100 Total 52280.0 sf 41 P Pervious 0.039 Acres SCALE 1'=100' Impervious O.W Acres 06 Field Ex May Creek Basin(for design) Total 156736.75 sf Drainage Basin Pervious 1.67 Acres Impervious 1.93 Acres EkBASEBALL FIELD Total Site 6.64 Acres Existing Ouff all Undeveloped Lake Wa DrainMage Basin Existing Ouff all ;� To May Creek Drainage Basin � Nw Drainage Basin 42' -r May Creek El IDrainage Basin EX DLAY SH D E 28- .2 2A 54 if ashy ain /PAC LOT- C 45 PARKING L0f/j--A El -0 'S Bbz w 0 7E 27'�— Existing Outfall To o East Lake Washington N Drainage Basin Figure Existing Conditions O PROJECT: Kennydale Elementary School DESIGNED BY: sas DATE: 12-09-04 PROJECT NO, C040055-02 CLIENT: Renton School District CHECKED BY: tbb SHEET OF 413 PINE STREET-SUITE 300 SEATTLE,WA 98 101 P: 206/343-0460 F: 206/343-5691 COUGHLIN PORTERLUNDEEN A CONSULTING STRUCTURAL AND CIVIL ENGINEERING CORPORATION Undeveloped Lake Wa Basin Field Basin ELI Pervious 0.28 Acres Total 80104.0 sf I Inn er .03 Acres Pervious 1.75 Acres AM"38*w 11 Impervious 0.086 Acres N 234- ........... Prop Lake Wa Basin(for design) ■ 0 25 50 100 Total 52280.0 sf ..41.... Ph Pervious 1.011 Acres SCALE 1'=100' Impervious 0.213 Acres GRO Field Prop May Creek Basin(for design) Total 156736.75 sf Drainage Basin Pervious 0.89 Acres GRASS Impervious 2.28 Acres EX'BASEBALL FIELD Total Site 6.64 Acres xisting Outfall To May Creek Undeveloped Lake Wa Drainage Basin Proposed Ouffd Drainage Basin r To May Creek 21 Drainage Basin 42' -A T'Opp X 28': Al. A- I!- I 54" PROPOS D BUILDIN6-..---:------4:........ ----- -------------------- ---- --------------------------- ------- -------- 4... opostl t ak Washnil BASN T . ..... -tit- ............ .......... LOT EU J 0 01 27' D 0 Proposed Ouff all To East Lake Washington Drainage Basin Figure 3 - Developed Conditions PROJECT: Kennydale Elementary School DESIGNED BY: sas DATE: 12-09-04 PROJECT NO. C040055-02 CLIENT: Renton School District CHECKED BY: tbb SHEET OF 413 PINE STREET-SUITE 300 SEATTLE,WA 98 101 P: 206/343-0460 F: 206/343-5691 ........... L VA Y ME ft -0-,U 'W"'100 -:4 k I Mr A R '6v MWIN -W V.. e,A W-1.0-H A., A* tag Es 7. Ufkl N A V I U D4 EE4 5 ZE! IL N q tmm'WON WIN- i-I IN , R IR A M. I I M '_U_L' r�H-1 J t 4#11 5i_ ;-T it ENROTM W, A" j, 4 IN 1 Vim —.0 A, 01 I W 7A Mb PEI J 3b: L '713�� T: WIN R l5 131 1 Pr— ;'Af 1 1/2 0 1 The boundaries of the sensitive areas dis- Numbered wetlands, except those with an Wetlands Wetlands Dwwamish 4 played on these maps are approximate. 41a" or "b" designation are Included In the Additional sensitive areas that have not King County Wetlands Inventory. The been mapped may be present onfa devel- locations of wetlands designated "all have Open Water T2 3 MILE opment proposal site. Where c1l ferences been verified on th Inte bdy a variety of inds d:sls 'b"are map- occur between what is illustrated on these sources. Watil- g ate N maps and the site conditions,the actual pre- ped in the U.S. Fish and Wildlife Service Basin Boundaries 0 14 sence or absence on the site of the sensitive lVational Wetlands Inventory,but their loca- -11 area - as defined In the Sensitive Area tions have not been field verified. Sub-basin Boundaries Ordinance-is the legal control. There may be ga in the numbering se- 42 I Pi U quence within ndivid al drainage basins. J9 .......... 91111 A*001 *06-9-1 t, ! J` 1`' Y I„ t'( f �✓> '�' - l �i�g Ir' 1�1-3z� „'\tt i..'♦- 'k - c-IL,-,�-k ,-[ ^--v • '.r .�'_ -r:.`,'�:.`' - ;:-,:, ; 'tHr:.--,.au '} 1 (t _ a r''`,. ''�'' 9acLy ---•� '.3:'�" �1'" l ;i:. b=: ,t �"-'"�� `t �::r. •:vt 7[7 z f.r:'Ti. . "n[.0 ;7.• f�. f i3• f' :`%�^-- -,. If S d.l::--=c ,. .�-, ,�`.irl� qr r.,� � .�' � t'::': ,- •.-�: ,ae.�•i. r-. .,, , •v.: .-. :.-T.... •,.__ - f� '-'t- 'i •::i i, .'.L.: �. ..ate-r'" :' ) _•n_' .,.�r. 18 _t �' ! 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'. -,i �.., c. :I I 11 4 � ...� u t ��_.. '^1C 'I( ,yn Mnrvr tl `�,.� '�. •m I _w• `r - � :ems • _ SSA i ".. t r:, .I^'[:.e , ... :-, .'•i. k.y,,," '�S4 t - 1� - '!•- 1:.- ,,t ,9� � ."'t X d ^s� r,' i - x - r,• f • : ' .:; .. ' Ilitl - �.:'ip�� _.-) ;, '.I 1. J ,•N•"--q ! J .'t 4 .,.. .,:.. .. ''�- .: ., ,• ,.,e. Y1- - — eta r'+ 0,:�� ��. ., . . .,` r.�, elt '. -:; 'i � nr � 1. i"(-..�' I r. •.r.st-,--� _ o G: 1. 2;1A ? w ' � 1 -�:<-x.1,try ... . :' .. I .^ :I�-• 1?. � _�, � a { q� f-: ! 1 - AW - s 4 u>/ C Se F`` '� - - r rI ;1:.. _ t - r 17` �z, � �: r:r �-� •-�.. _L. k. ++ I r I P .. I , , g - . -..,-..•��� _ -d. ;�. � ..fir ! i I:: .°-�--; .4:'� f •�' 1 -:;; t � J`� � .-''��h��1 �... f ei � yt 1, L ., ^� a, ter\ •, 1 r Its f E :- . n _ ,xn x ! `\' _ .�.: .•-:Win' , -- t -� aY`_ is�.T. �_. _ - ! �F -{ - ( J c•�;JKt L' 4 -t= I '1 k 1 ^ I I s ' I( Ym _' � ���� ,/<�']�� 1 Li�l ��� � l�\,+��[s F :I 1� 1 t t n� 4 1. 1 T• �',: ,�i ,Z ,r,., % ,` '�'� 1 41 1/2 0 - t[�a• / t5 ;at•... 1 The boundaries of the sensitive areas dis• See wetlands and played on these maps are approximat landslide hazard maps for ° e, additional potential seismic hazard areas. Seismic ®� ��'� Additional sensitive areas that have not Wetlands and landslide areas are susceptible 4 F been mapped may be present on a devei- to failure during earthquakes. Other seismic PvIIL_ opment proposal site. Where differences hazard areas not shown on this map areAreas occur between what is Illustrated on these shorelines underlain by lacustrine sediments; 2 7 maps and the site conditions,the actual pre- these are susceptible to liquefaction. 73 sence or absence on the site of the sensitive 9 area. - as defined in the Sensitive Area 14 Ordinance-is the legal control. to ' ty - ._- +- ' e - _ _ _ . _ . _, Ft GEt P.E. fa _ �` _ ,,_„ i _ �� _ _ i L - j , ._ - - - _ ' , ,, . - r \ a; i:':1 r 11 ._-,. r e - �,l t �..: T c / !,.;.. , I "- ,._� l'rl ::- -. i - i&i I'` ,f. '`'-` > , 1 - f 1 ,'. .j 1 1 ..t i !.7 i- I :c 1 ,, :'al - - i f I Y -_d-, (r - a - r .I 1 1 r"`� 1 - -r ,.,: •,? is -,�; / 1 i �.'T' - _ j.r I t i.;I 1 1 I '.. I ! "..: _- ^]- :r '.C`. f ..i. ii(- N k : - k:- t _L-1+:,,r - g.. . I .r = - •,a , -( t y ,;.f.-' r (L �i I .1,1 i ( ,:(` :-`i 1 } .. r.':I. .:-'Y' Ir] ..-� C' t t J i.,.. F i .t.i d. t ik i i I'�" i - _- 1 . , . - - - i _ .-. _ 1 _: , __ rr�`�' i.. 1 4, . 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A,._ _ _-� ,� :a ,x...- 1' v lr �r.,:z�,•" r :c: r y `' i I _, os S'i`�' . :: - .�'.:. �.�.r-^,-I ,S:-_ ,.wS _ ^ �.. class 1 1 9/2 0 1 The boundaries of the sensitive areas tlis- One- hundred-year fioodpiains extend be ��� �v and 1'0- � r � l��� played on these maps are approximate, yond those shown on maps Flood In- r� as-®-�- ® Class 2(with salmonids) I ,' - been mapped sensitive areas that have not surance Rate Maps he not always show the � � �� � (pa 2 g S s ��7rs� i°'�� r been mappad may be present on a devel- floodplain to the headwaters of streams. ass teMial;Salmonld g MILE opment proposal site. Where differences use undetermined) occur between what is illustrated on these : 9 tC �- maps and the site conditions,the actual pre- © a ® ® ® Class 3 Bence.or absence on the site of the seYtsitkve „) area - as defined in the Sensitive Area ' i00-bear Floodplains _ Unclassified �t y , ,_, - ordinance-is the legal control. r ...�� : _ _ I .1 irk- .'.rybt" - as'° ...^`S�� -r:��+.r�� 'pia-:••�� cu.;.-- L- -. �:.,,__ -""+-- -. _. -:-- _._ - - - - __- - - _ -._-- _..,m.�---.-":co-+;:r71 .. am::�i8 .X.-s-"_ :.i .,--.::J4--"a -.. -. 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I 1 1 _ (�'�,:.+-. ,i 1. ..�1..; \[[I��''u5. � S` ��.. ...� e ^�� •��1 N ID v �' 9 .f ,"� r "l• y. l.. .n 111 5 1 ,`4 f �+-� - °^� '�:�.•1 ( I a °' :��/••L '�#� �+ -. ����1 .A- 1t �' •�% �, �"� - i=�� /i 1 d-. 1 �j '.�) ) �I� �-,,-te 1q II ..s,�- ) dl}t td , `i�, )gr �,. {.'t .k,• - ' - :.:� - II _..F�I , r`�I fl �.(Ij jar>.') �7u ,1; II_'� ., _ ` _ y �, - -- �- ;'r i: y.' // � � �1 1 !r f,! y�;{ t �-'�;�E���:`�j It 1``rr,�'•``� r C 'f - ?it t': �' �. / � I � d� ; � � +, J I" G r'f" r trf _ �.1 •s•. .�`E'4 }} t J 1 1 -I�� �• j ...... .�� - v �f�r � �1�1�.._1>` � r- r�� -"u .r� "����� P-r'�,VV D v m a X W ■ ■ APPENDIX B ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ COUGHLIN PORTER LUNDEEN Kennydale Elementary School ■ 17 Renton,Washington ■ Detention Vault Calculations i COUGHLIN PORTER LUNDEEN Kennydale Elementary School 18 Renton,Washington Kennydale Elementary School - Level 2 Detention Vault Retention/Detention Facility Type of Facility: Detention Vault Facility Length: 110. 00 ft Facility Width: 20.00 ft Facility Area: 2200. sq. ft Effective Storage Depth: 5 . 00 ft Stage 0 Elevation: 230.75 ft Storage Volume: 11000. cu. ft Riser Head: 5 .00 ft Riser Diameter: 12 . 00 inches Number of orifices: 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0. 00 2 .75 0.459 2 2 .25 3 . 00 0.405 6.0 3 3 .25 2 .50 0.224 6.0 Top Notch Weir: None Outflow Rating Curve: None Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 0.00 230.75 0. 0.000 0.000 0.00 0.03 230.78 66. 0.002 0.035 0. 00 0.06 230. 81 132 . 0. 003 0.049 0. 00 0 .09 230.84 198. 0 .005 0 .060 0.00 0.11 230. 86 242 . 0. 006 0.069 0 . 00 0.14 230. 89 308 . 0. 007 0.078 0. 00 0 .17 230.92 374 . 0.009 0.085 0.00 0.20 230.95 440 . 0. 010 0.092 0.00 0.23 230.98 506. 0.012 0.098 0.00 0.26 231.01 572 . 0. 013 0.104 0 . 00 0.36 231. 11 792 . 0.018 0.123 0.00 0.46 231.21 1012 . 0.023 0. 139 0. 00 0.56 231.31 1232 . 0.028 0.153 0.00 0.66 231.41 1452. 0.033 0.166 0.00 0.76 231.51 1672 . 0.038 0.179 0.00 0 . 86 231.61 1892 . 0.043 0.190 0.00 0.96 231.71 2112 . 0.048 0.201 0.00 1.06 231.81 2332 . 0. 054 0.211 0.00 1. 16 231.91 2552 . 0.059 0.221 0.00 1.26 232 .01 2772 . 0.064 0.230 0.00 1. 36 232 .11 2992 . 0.069 0.239 0.00 1.46 232 .21 3212 . 0.074 0.248 0.00 1.56 232 .31 3432 . 0.079 0.256 0.00 1. 66 232 .41 3652 . 0.084 0.264 0.00 1.76 232 .51 3872 . 0.089 0.272 0.00 1. 86 232 .61 4092 . 0.094 0.280 0.00 1. 96 232 .71 4312 . 0.099 0.287 0.00 2 . 06 232 .81 4532 . 0 .104 0.294 0. 00 2 . 16 232 .91 4752 . 0.109 0.301 0.00 2 .25 233 .00 4950. 0.114 0 .308 0.00 2 .28 233 .03 5016. 0.115 0.312 0.00 2 .31 233 . 06 5082. 0.117 0 .321 0.00 2 .34 233 .09 5148. 0. 118 0.335 0 . 00 2 .38 233 .13 5236. 0.120 0.352 0.00 2 .41 233 .16 5302. 0.122 0.374 0.00 2 .44 233 . 19 5368. 0.123 0 .399 0 . 00 2 .47 233 .22 5434. 0. 125 0.427 0 .00 2 .50 233 .25 5500. 0 .126 0.446 0. 00 2 .60 233 .35 5720. 0.131 0.475 0 .00 2 .70 233.45 5940. 0. 136 0.501 0.00 2 .80 233 .55 6160. 0.141 0.524 0 .00 2 .90 233 .65 6380. 0. 146 0.546 0.00 3 .00 233 .75 6600. 0.152 0.567 0 .00 3 .10 233 .85 6820. 0. 157 0.586 0.00 3 .20 233 .95 7040. 0 . 162 0.605 0.00 3 .25 234 .00 7150. 0.164 0.614 0. 00 3 .28 234 . 03 7216. 0.166 0 .620 0 .00 3 .30 234 . 05 7260. 0.167 0.629 0.00 3 .33 234 .08 7326. 0. 168 0 .642 0 .00 3 .35 234 . 10 7370. 0.169 0.657 0.00 3 .38 234.13 7436. 0. 171 0.675 0 .00 3 .41 234 . 16 7502. 0.172 0. 697 0.00 3 .43 234.18 7546. 0 . 173 0.718 0.00 3 .46 234 .21 7612 . 0.175 0.727 0.00 3 .56 234.31 7832 . 0. 180 0.760 0.00 3 .66 234 .41 8052 . 0.185 0.790 0.00 3 .76 234.51 8272. 0. 190 0 . 818 0.00 3 .86 234 .61 8492. 0.195 0.845 0.00 3 .96 234 .71 8712 . 0.200 0.870 0.00 4 .06 234 .81 8932 . 0.205 0.894 0 .00 ■ 4 .16 234 .91 9152 . 0.210 0 . 917 0.00 4 .26 235 .01 9372. 0 .215 0.939 0.00 4 .36 235.11 9592 . 0.220 0.961 0.00 ■ 4 .46 235.21 9812 . 0 .225 0.982 0.00 4 .56 235 .31 10032. 0.230 1.000 0.00 4 .66 235 .41 10252 . 0 .235 1.020 0.00 4 .76 235 .51 10472 . 0.240 1.040 0.00 4 .86 235 .61 10692 . 0.245 1.060 0. 00 4 .96 235.71 10912 . 0 .251 1. 080 0.00 5 .00 235.75 11000. 0.253 1.090 0 . 00 5 .10 235.85 11220. 0 .258 1.410 0. 00 5 .20 235 . 95 11440. 0.263 1.990 0.00 5 .30 236.05 11660. 0.268 2 .740 0. 00 5 .40 236.15 11880. 0.273 3 .550 0.00 5 .50 236.25 12100. 0.278 3 .850 0.00 5 .60 236.35 12320. 0.283 4 .120 0.00 5 .70 236.45 12540. 0 .288 4.370 0. 00 5 . 80 236.55 12760. 0 .293 4 .610 0.00 5 .90 236.65 12980. 0.298 4 .830 0.00 ■ 6.00 236.75 13200. 0.303 5.040 0. 00 6.10 236.85 13420. 0.308 5.240 0.00 6.20 236.95 13640. 0 .313 5 .430 0.00 6.30 237.05 13860. 0 .318 5.610 0 . 00 6.40 237.15 14080. 0.323 5.790 0.00 6 .50 237.25 14300. 0.328 5.960 0 . 00 6.60 237.35 14520. 0.333 6.130 0.00 6.70 237.45 14740. 0.338 6.290 0. 00 6. 80 237.55 14960. 0.343 6.450 0.00 6.90 237.65 15180. 0.348 6. 600 0.00 ■ 7.00 237.75 15400. 0 .354 6.750 0. 00 Hyd Inflow Outflow Peak Storage Target Calc Stage Elev (Cu-Ft) (Ac-Ft) 1 1.27 1.26 0. 97 4 .42 235 .17 9735 . 0.223 2 0.67 ******* 0.55 2 .93 233 .68 6455. 0.148 3 0. 64 ******* 0.55 2 .90 233 .65 6373 . 0.146 4 0.76 ******* 0.53 2 .81 233 .56 6190. 0. 142 5 0.63 ******* 0.48 2 .63 233 .38 5792. 0.133 6 0.70 ******* 0.37 2 .40 233 .15 5290. 0.121 7 0.53 ******* 0.25 1.48 232 .23 3263 . 0.075 8 0.58 ******* 0.24 1.34 232 .09 2946. 0. 068 i i i t i i ■ i compare.prn Duration comparison Anaylsis Base File: existing.tsf New File: rdout.tsf Cutoff units: Discharge in CFS -----Fraction of Time----- ---------Check of Tolerance------- Cutoff Base New %Change Probability Base New %Change 0.309 0.24E-02 0.82E-03 -66.7 0.24E-02 0.309 0.244 -21.0 0. 343 0.18E-02 0.64E-03 -65.2 0.18E-02 0.343 0.264 -23.0 0. 377 0.13E-02 0. 52E-03 -61.0 0.13E-02 0. 377 0.284 -24.5 0.410 0.98E-03 0.44E-03 -55.0 0.98E-03 0.410 0.301 -26.6 0.444 0.68E-03 0.38E-03 -45.2 0.68E-03 0.444 0.335 -24.5 0.477 0. 55E-03 0.24E-03 -55.9 0. 55E-03 0.477 0.367 -23.2 0. 511 0.42E-03 0.11E-03 -73.1 0.42E-03 0. 511 0.414 -18.9 0. 544 0.28E-03 0.49E-04 -82.4 0.28E-03 0. 544 0.459 -15.6 0. 578 0.21E-03 0.00E+00 -100.0 0.21E-03 0. 578 0.482 -16.5 0.611 0.16E-03 0.00E+00 -100.0 0.16E-03 0.611 0. 505 -17.3 0.645 0.98E-04 0.00E+00 -100.0 0.98E-04 0.645 0. 524 -18.7 0.679 0.49E-04 0.00E+00 -100.0 0.49E-04 0.679 0. 544 -19.8 0. 712 0.49E-04 0.00E+00 -100.0 0.49E-04 0.712 0. 544 -23.6 0 k Pv"_ There is no positive excursion L,j_vn,L 2 Maximum negative excursion = 0.113 cfs (-27.3%) occurring at 0.414 cfs on the Base Data:existing.tsf and at 0.301 cfs on the New Data:rdout.tsf / ■ / Page 1 ■ Existing Peak Flows ■ Flow Frequency Analysis Time Series File:existing.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- , Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0 . 617 6 2/09/01 2 :00 1.26 1 100. 00 0.990 0 .488 8 1/05/02 16 :00 0 .745 2 25 . 00 0.960 0 .745 2 2/27/03 7:00 0 .744 3 10. 00 0 .900 0 .512 7 8/26/04 2 :00 0.653 4 5.00 0.800 0. 620 5 10/28/04 16:00 0 .620 5 3 .00 0.667 0 .653 4 1/18/06 16:00 0.617 6 2.00 0.500 0.744 3 10/26/06 0 :00 0.512 7 1.30 0 .231 1.26 1 1/09/08 6:00 0.488 8 1. 10 0 .091 ■ Computed Peaks 1.09 50. 00 0.980 ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Developed Peak Flows Flow Frequency Analysis Time Series File:developed.tsf ■ Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.632 6 2/09/01 2 :00 1.27 1 100. 00 0 .990 0.527 8 1/05/02 16:00 0.851 2 25.00 0. 960 0.757 3 2/27/03 7 :00 0.757 3 10. 00 0 .900 0.585 7 8/26/04 2 :00 0.700 4 5.00 0. 800 0.700 4 10/28/04 16 :00 0.673 5 3 . 00 0 . 667 0.673 5 1/18/06 16:00 0. 632 6 2 .00 0.500 0. 851 2 10/26/06 0 :00 0.585 7 1.30 0.231 1.27 1 1/09/08 6:00 0.527 8 1. 10 0.091 rComputed Peaks 1.13 50.00 0. 980 1 ■ Detention Pond Calculations COUGHLIN PORTER LUNDEEN Kennydale Elementary School 19 Renton,Washington ■ 3/24/05 1 :40 : 13 pm Coughlin, Porter, Lundeen Inc . page 1 Kennydale Elementary School Lake Washington Drainage Basin 3-23-05 Combination Pond (Detention) BASIN SUMMARY BASIN ID: dev100yr NAME : Developed Conditions 100-Year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 22 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 . 21 Acres 1 . 01 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 90 . 00 98 . 00 TC. . . . : 10 . 00 min 6 . 30 min . ABSTRACTION COEFF: 0 . 20 PEAK RATE : 0 . 95 cfs VOL: 0 . 36 Ac-ft TIME: 480 min BASIN ID: dev10yr NAME : Developed Conditions 10-Year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 22 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 2 . 90 inches AREA. . : 0 . 21 Acres 1 . 01 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 90 . 00 98 . 00 ABSTRACTION COEFF: 0 . 20 TC. . . . : 10 . 00 min 6 . 30 min PEAK RATE: 0 . 69 cfs VOL: 0 . 26 Ac-ft TIME: 480 min j BASIN ID: dev2yr NAME: Developed Conditions 2-Year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 22 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0 .21 Acres 1 . 01 Acres ■ TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 90 . 00 98 . 00 TC. . . . . 10 . 00 min 6 . 30 min ABSTRACTION COEFF: 0 . 20 PEAK RATE : 0 . 46 cfs VOL: 0 . 17 Ac-ft TIME : 480 min BASIN ID: ex100yr NAME: Existing Conditions 100-Year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 89 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 . 04 Acres 0 . 85 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 90 . 00 98 . 00 TC. . . . . 10 . 00 min 6 . 30 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0 . 71 cfs VOL: 0 . 27 Ac-ft TIME : 480 min 3/24/05 1 :40 : 13 pm Coughlin, Porter, Lundeen Inc . page 2 Kennydale Elementary School Lake Washington Drainage Basin 3-23-05 Combination Pond (Detention) BASIN SUMMARY BASIN ID: exlOyr NAME : Existing Conditions 10-Year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 89 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 2 . 90 inches AREA. . : 0 . 04 Acres 0 . 85 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 90 . 00 98 . 00 ■ TC. . . . : 10 . 00 min 6 . 30 min ABSTRACTION COEFF : 0 . 20 PEAK RATE : 0 . 52 cfs VOL: 0 . 19 Ac-ft TIME : 480 min BASIN ID: ex2yr NAME : Existing Conditions 2-Year SBUH METHODOLOGY ■ TOTAL AREA. . . . . . . : 0 . 89 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0 . 04 Acres 0 . 85 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 90 . 00 98 . 00 TC. . . . . 10 . 00 min 6 . 30 min ABSTRACTION COEFF: 0 . 20 PEAK RATE: 0 . 35 cfs VOL: 0 . 13 Ac-ft TIME: 480 min r 3/26/05 5 : 52 : 1 pm Coughlin, Porter, Lundeen Inc . page 1 iKennydale Elementary School Lake Washington Drainage Basin 3-23-05 Combination Pond (Detention) STAGE STORAGE TABLE TRAPEZOIDAL BASIN ID No. LWPond2 Description: Lake WA Drainage Basin POND 2 Length: 38 . 00 ft . Width: 18 . 00 ft . Side Slope 1 : 2 Side Slope 3 : 2 Side Slope 2 : 2 Side Slope 4 : 2 Infiltration Rate : 0 . 00 min/inch STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --AC-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 234.75 0.0000 0.0000 235.20 330.97 0.0076 235.70 755.45 0.0173 236.20 1244 0.0285 234.80 34.481 0.0008 235.30 410.97 0.0094 235.80 847.65 0.0195 236.25 1296 0.0298 234.90 105.14 0.0024 235.40 493.38 0.0113 235.90 942.83 0.0216 235.00 178.08 0.0041 235.50 578.25 0.0133 236.00 1040 0.0239 235.10 253.35 0.0058 235.60 665.60 0.0153 236.10 1141 0.0262 1 GP �JJ -6%fsf vrA JA i 5/4/05 9 : 53 : 23 am Coughlin, Porter, Lundeen Inc . page 2 Kennydale Elementary School Lake Washington Drainage Basin 3-23-05 Combination Pond (Detention) STAGE DISCHARGE TABLE MULTIPLE ORIFICE ID No. PondOr2 Description: LakeWA Bailin Pond Orifice 2 Outlet Elev: 234 . 75 Elev: 232 . 75 ft ✓/ Orifice Diameter: 4 . 3000 in. Elev: 235 . 35 ft✓ Orifice 2 Diameter: 2 . 0000 in. STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---Cfs-- ------- (ft) ---Cfs-- ------- (ft) ---Cfs-- ------- (ft) ---Cfs-- ------- 234 75 0.0000 235.20 0.3366 235.70 0.5533 236.20 0.7043 234.80 0.1122 235.30 0.3721 235.80 0.5870 236.25 0.7175 234.90 0.1943 235.40 0.4288 235.90 0.6186 235.00 0.2509 235.50 0.4766 236.00 0.6485 235.10 0.2968 235.60 0.5169 236.10 0.6770 1 5/4/05 9 : 53 : 23 am Coughlin, Porter, Lundeen Inc . page 1 Kennydale Elementary School Lake Washington Drainage Basin 3-23-05 Combination Pond (Detention) STAGE DISCHARGE TABLE NOTCH WEIR ID No. PONDWEIR Description: KENNYDALE POND WEIR Weir Length: 0 . 1700 ft . Weir height (p) : 0 . 5000 ft . Elevation 235 . 65 ft . Weir Increm: 0 . 10 STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---CfS-- ------- (ft) ---CfS-- ------- (ft) ---CfS-- ------- (ft) ---CfS-- ------- 235.65 0.0000 235.80 0.0276 236.00 0.0735 236.20 0.0908 235.70 0.0059 235.90 0.0521 236.10 0.0877 236.25 0.0871 ■ r ■ ■ r ■ ■ ■ i i ■ ■ 3/24/05 1 :40 : 14 pm Coughlin, Porter, Lundeen Inc . page 4 Kennydale Elementary School Lace Washington Drainage Basin 3-23-05 Combination Pond (Detention) STAGE DISCHARGE TABLE COMBINATION DISCHARGE ID No. OR/WEIR Description: ORIFICE W/WEIR V_'C- Structure : PondOr2 Structure : Structure : PONDWEIR Structure : Structure : z STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---CfS-- ------- (ft) ---CfS-- ------- (ft) ---CfS-- ------- (ft) ---CfS-- ------- 234.75 0.0000 235.20' 0.3366 235.70 0.5592 236.20 0.7951 234.80 0.1122 235.30 0.3721 235.80 0.6145 236.25 0.8047 234.90 0.1943 235.40 0.4288 235.90 0.6706� A� 235.00 0.2509 235.50 0.4766 236.00 0.7220 235.10 0.2968 235.60 0.5169 236.10 0.7647 z� - I� IDOY2 -.o S = L',S.9'7 EL - 21.)S.6S -4 3/24/05 1 :40 : 16 pm Coughlin, Porter, Lundeen Inc . page 5 Kennydale Elementary School Lake Washington Drainage Basin 3-23-05 Combination Pond (Detention) LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> STORAGE <--------DESCRIPTION---------> (cfs) (cfs) --id- --id- <-STAGE> id VOL (cf) 2-year .... ....... ........... . 0.35 0.46 LWPond2 OR/WEIR 235.23 13 355.50 cf 10-year .......... ....... .... . 0.52 0.69 LWPond2 OR/WEIR 235.59 14 659.31 cf 100-year ........... .... . ..... 0.71 0.95 LWPond2 OR/WEIR 235.97 15 1013.40 cf t i i r y ■ i i i Biofiltration Swale Calculations i COUGHLIN PORTER LUNDEEN Kennydale Elementary school 20 Renton,Washington Kennydale Elementary School Bioswale Design—5/4/05 Treatment areas used for design. KCRTS Program. . .File Directory: C:\KC_SWDM\KC—DATA\ [C] CREATE a new Time Series ST 0. 00 0.00 0.000000 Till Forest 0.00 0.00 0.000000 Till Pasture 0.45 0.00 0.000000 Till Grass 0. 00 0.00 0.000000 Outwash Forest 0.00 0.00 0.000000 Outwash Pasture 0. 00 0. 00 0.000000 Outwash Grass 0.00 0.00 0.000000 Wetland 0.91 0.00 0.000000 Impervious BioswaleTreatmentFlow.tsf T 1. 00000 F [T] Enter the Analysis TOOLS Module [P] Compute PEAKS and Flow Frequencies bioswaletreatmentflow.tsf BioswaleTreatmentFlow.pks [R] RETURN to Previous Menu [X] eXit KCRTS Program �� wti ar - U j o,a q S7 � " � � �`� (cam,.;•-�(� -tea o��'v! �©S`"'�.'" ■ Kennydale Elementary School Bioswale Design - 5/4/05 Water quality design flow calculations = 60% of the 2-year Storm Flow Frequency Analysis Time Series File:bioswaletreatmentflow.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- FlowRate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.433 6 8/27/01 18 :00 1.30 1 100 . 00 0 . 990 0. 304 8 1/05/02 15 :00 0.917 2 25.00 0. 960 0. 917 2 12/08/02 17 :15 0.602 3 10.00 0 .900 0.348 7 8/23/04 14 :30 0.514 4 5. 00 0 . 800 0.510 5 11/17/04 5 :00 0.510 5 3 . 00 0.667 0.514 4 10/27/05 10 :45 0.433 6 2 . 001 0 .500 0. 602 3 10/25/06 22 :45 0.348 7 1.30 0.231 1.30 1 1/09/08 6 :30 0.304 8 1.10 0. 091 Computed Peaks 1.17 50. 00 0 . 980 i CO . t-r � © CF5 COUGHLINPORTERLUNDEEN A CONSULTING STRUCTURAL AND CIVIL ENGINEERING CORPORATION BASIC BIOFILTRATION SWALE CALCULATIONS Size Swale for biofiltration function: Use Manning's Equation to Verify Swale Capacity: Where: Q = Flow, cfs SUMMARY A= Cros-sectional area of flow, sq ft. Base Width = 10.0 ft s = Swale slope, ft/ft. Side Slope= 3 ft:ft n = Manning's roughness coefficient Swale Length = 100 ft y= Flow height, ft. WQ Depth= 0.17 ft b= Swale base width, ft. (50ft max.) 100-yr Depth= 0.30 ft z= Side slope, ft:ft. I Total Depth= 1.30 ft Hr= Hydraulic Radius, ft. Given: Base Width: b= 8.00 2' < b< 101, if b> 10', see 1988 KC Side Slope: z= 3 Surface Water Design Manual, 6.3.1 Q (design flow) Q= 0.259 Qwn= 60% 2-YR KCRTS DEV. (15-min. time step) Design Flow Ht y= 0.167 For design only y=2"or 4'; depending on site conditions Manning's"n" n= 0.2 For design only Swale Slope s= 1.0% slope must be between 1% -6% Swale Length L= 100 For design only jUsing Manning's Equation: A= (b+z*y)*y A=JIM sf Hr=A/((b)+(2*y*(1+z^2)^.5)) Hr= ft ar�n vq Q(d)=(1.49*A*(Hr)^0.667*(s)^0.5)/n Q(d) �,,.�(i� cfs> EEM Modify base(b) until Q(d)>Q(wq) Check Velocity for Biofiltration Function: V= Q/A V 4 fps< 1 Verify Velocity less than 1.0 fps Required Length of Swale: Hydraulic residence time t= s VEft. fps L = V wQ*540 Lreqft Verify Length greater than 100 ft. Bioswale length (site dependant) t-site= Verify Allowable Length >= Required Length If the proposed site does not have sufficient room to provide the required biofiltration swale length, reduce swale length and increase bottom width to provide an equivalent top area. Required Biofiltration Area: Water Surface Area at Design Depth '4 5�68'A t * * *op. = b+2 z y) t-rev tip' sf �� .�- ' Project: Kennydale Elementary Designed By: BSB Date 2123/05 Project No. C04-0055-02 Client: McGranahan Checked By: TBB Sheet I of 2 Water quality 2-23-05.xls COUGH LINPORTERLUN®EEN A CONSULTING STRUCTURAL AND CIVIL ENGINEERING CORPORATION BASIC BIOFILTRATION SWALE CALCULATIONS Adjust Swale Layout to Fit Site if L< 100ft. or<Allowable Length bf= increase of bottom width bf= 2.00 ft Lf= reduced swale length LfQ ft A Popp+1)=(bf+bswale)*lf A Popp+,)= sf> , �* Modify base(bf) until Atop>A,oPp+,> New Bottom Width: b - ^,4�1:}� ft Using Manning's Equation: A = (b+z*y)*y A=LINTaRlsf Hr=A/((b) +(2*y*(1+z"2)A.5)) Hr a ft Q(d)=(1.49*A*(Hr)^0.667*(s)^0.5}/n Q(d) d 3. cfs> Verify Q(d)>Q(wq) Check Velocity for Biofiltration Function: V= Q/A V ,G 10" f p s< 1 Verify Velocity less than 1.0 fps Analyze Swale for Conveyance Capacity&Velocity Given: Base Width: b ft Side Slope: z Q100 Q100 g cfs Qc= 100-YR 24 HR DEV. . Manning's"n" n= 0.2 Check table 4.4.1 B in KCSWDM Swale Slope S � f� Using Manning's Equation: By Trial & Error y= 0.30 ft Flow height A =(b+z*y)*y A= sf Hr=A/((b) +(2*y*(1+z"2)A.5)) Hr- ft Q =(1.49*A*(Hr)^0.667*(sl)^0.5)/n Quo cfs> _ Verify Qf.>Q(d) Check Velocity V= Q/A V 3 fps< 3.0 Verify Velocity is less than 3.0 fps ■ Required Depth of Swale Including Freeboard Total Depth (TD) = 100yr design depth + 1 foot TD= ft Top Width (TW) = b+(2*(z*TD) TW= ft Required Land Area Area of water surface at freeboard L*TW Aconv a m Sf - Project: 'rennydale Elementary Designed By: oSB Date 2/23/05 Project No. C04-0055-02 Client: McGranahan Checked By: TBB Sheet 2 of 2 Water quality 2-23-05.xis ■ Water Quality Vault Calculations ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ COUGHLIN PORTER LUNDEEN Kennydale Elementary School 21 Renton,Washington ■ COUGHLINPORTERLUNDEEN A CONSULTING STRUCTURAL AND CIVIL ENGINEERING CORPORATION King County Water Quality Calculation Cover Sheet Water Quality Menu: Basic (From King County Water Quality Applications Map) Water Quality Treatment Method: Wet Pond Rain Type Data: Soil Type Data From KCSWDM Figure 3.2.2.A page 3-22 From SCS Soils Map Rainfall Region: SEATAC SCS Soils Type: Scale Factor: From Table 3.2.2.13 From KCSWDM Figure 6.4.I.A SCS Soil Group: Mean Annual Storm: 0.47 KCRTS Soil Group: Site Areas Total Site Area: Existing Conditions fro posed Conditions Till Forest (acres) Till Forest (acres) Till Pasture (acres) Till Pasture (acres) Till Grass (acres) Till Gross (acres) Outwash Forest (acres) Outwash Forest (acres) Outwash Pasture (acres) Outwash Pasture (acres) Outwash Grass (acres) Outwash Grass (acres) Wetland (acres) Wetland (acres) Impervious (acres) Impervious 0.337 (acres) Total (acres) Total �. (acres) Flow Data Existing Conditions Proposed Conditions Rank Return Flow Flow Rank Return Flow Flow Period I hr 15 min Period (I hr) (15 min) 1 100 1 100 0.979 2 25 2 25 0.748 3 10 3 10 0.537 4 5 4 5 0.442 5 3 5 3 0.419 6 2 6 2 0.395 7 1.3 7 1.3 0.318 8 1.1 8 1.1 0.276 Project: Kennydale Elementary Designed By: BSB Date 3/26/05 Project No. C04-0055-02 Client: McGranahan Checked By: TBB Sheet I of 5 ■ Water quality Vault 3-10-05.xis COUGH LINPORTERLUNDEEN A CONSULTING STRUCTURAL AND CIVIL ENGINEERING CORPORATION Wet Vault Sizing 1) Indentify Required Wet Pool Volume Factor(f) Based on Water Quality Menu f = 3 2) Determine Rainfall (R)for Mean Annual Storm Determined from Figure 6.4.1A(attached) R = Q 47 3) Calculate Runoff(Vr)from Mean Annual Storm Vr _ (0 9A,+0.25At9+0.10Atf+0.01Ao)x(R/12) (6-13) where: Vr volume of runoff from mean annual storm (cubic feet) Ai = area of impervious surface(square feet) Ate " area of till soil covered with grass (square feet) Atr area of till soil covered with forest(square feet) Ao = area of outwash soil covered with grass or forest(square feet) R/12 = a yr ��t �� °rainfall from mean annual storm(feet) 4) Calculate wetpool volume NO. Vb f X Vr (6-14) where: Vbwetpool volume (cubic feet) f = volume factor from Step 1 Vr = "a"11, runoff volume(cubic feet)from Step 3 5) Determine wetpool dimensions. Determine the wetpool dimensions satisfying the design criteria Geometry 1) Wetpond Shall be two cells seperated by a baffle or Berm 2) Wetponds with a volume less than 4,000 cubic feet may be one cell. Number of Wet Vault Cells Provided: 1 3) Sediment Storage shall be provided in the first cell-Minimum depth 1 foot Depth of Sediment Storage: 4) Depth of First Cell 4.5 4-8 ft 5) First Cell Top Length 35 ft First Cell Top Width 10 ft First Cell Bottom Length ft First Cell Bottom Width ft First Cell Top Area Esq ft First Cell Side Slope 0 :1 First Cell Bottom Area sq ft Area at Top of Sediment Storage sq ft First Cell Dead Storage Volume El, cu ft Project: Kennydale Elementary Designed By: BSB Date 3/26/05 Project No. Client: RSD Checked By: TBB Sheet I of I Water quality Vault 3-10-05.xis COUGHLINPORTERLUNDEEN A CONSULTING STRUCTURAL AND CIVIL ENGINEERING CORPORATION FIGURE 6.4.1.A PRECIPITATION FOR MEAN ANNUAL STORM IN INCHES(FEET) ST 1.0/ LA 1 2 ST 1.1 "+ 'J 11 LA 0.8 LA. 0.9 LA 1.XO r� r D16 r' ✓�, f,: F�..r.. //FIEF j fi f. . a r+ ��o. .. .. <.. D 0.47" (0.039') > Incorporated Area River/Lake .0.47" Major Road (0.0391) 0.521 043' NOTE:Areas east of the easternmost isopluvial should use 0.65 (0. b.5 6" 0.65"(0.054') inches unless rainfall data is available for the location of interest (0.0471) 24 The mean annual stone is a conceptual storm found by dividing the annual precipitation by the total number of storm events per year result,generates large amounts of runoff. For this application,till soil types include Buckley and bedrock soils,and alluvial and outwash soils that have a seasonally high water table or are underlain at a shallow depth(less than 5 feet)by glacial till. U.S.Soil Conservation Service(SCS)hydrologic soil groups that are classified as till soils include a few B,most C,and all D soils. See Chapter 3 for classification of specific SCS soil types. Figure 6.4.1 A - Precipitation for Mean Annual Storm Event Project: Kennydale Elementary Designed By: BSB Date 3/26/05 Project No. C04-0055-02 Client: McGranahan Checked By: TBB Sheet 3 of 5 Water quality Vault 3-10-05.xls Water Quality Pond Calculations 1 COUGHLIN PORTER LUNDEEN Kennydale Elementary School 22 Renton,Washington COUGHLINPORTERLUNDEEN A CONSULTING STRUCTURAL AND CIVIL ENGINEERING CORPORATION Wet Pond Sizing 1) Indentify Required Wet Pool Volume Factor(f) Based on Water Quality Menu f = 3 2) Determine Rainfall (R)for Mean Annual Storm Determined from Figure 6.4.1A(attached) R = 0'.47_ 3) Calculate Runoff(Vr)from Mean Annual Storm V, _ (0.9A, +0.25Af9+0.10Atf+0.01Ao)x(R/12) (6-13) where: Vr - 1 643 g 7 volume of runoff from mean annual storm (cubic feet) A; = 44039 area of impervious surface(square feet) Af9 9278 28 area of till soil covered with grass (square feet) Af 0 .' area of till soil covered with forest(square feet) A. = Q area of outwash soil covered with grass or forest(square feet) R/12 = 0 0392 r,. £ ;rainfall from mean annual storm(feet) ._. 4) Calculate wetpool volume(Vb). Vb f X Vr (6-14) where: Vb 4,930.; wetpool volume (cubic feet) f = 3, volume factor from Step 1 Vr = 1,643 =, runoff volume(cubic feet)from Step 3 5) Determine wetpool dimensions. Determine the wetpool dimensions satisfying the design criteria Geometry 1) Wetpond Shall be two cells seperated by a baffle or Berm 2) Wetponds with a volume less than 4,000 cubic feet or greater than 4:1 length to width ratio may be one cell. Number of Wetpond Cells Provided: 3) Sediment Storage shall be provided in the first cell-Minimum depth 1 foot Depth of Sediment Storage: 4) Depth of First Cell 4 4-8 ft 5) First Cell Top Length 105 ft First Cell Top Width 29 ft First Cell Bottom Length W-� sq ft First Cell Bottom Width ft First Cell Top Area ft First Cell Side Slope 2.5 :1 First Cell Bottom Area sq ft Area at Top of Sediment Storage sq ft First Cell Dead Storage Volume mcuft Project: Kennydale Elementary Designed By: BSB Date 1117105 Project No. C04-0055-02 Client: McGranahan Checked By: TBB Sheet I of I COUGHLINPORTERLUNDEEN Wet Pond Permit 1-16-05.xls Conveyance Analysis 1 COUGHLIN PORTER LUNDEEN Kennydale Elementary School 23 Renton,Washington Kennydale Elementary School Catch Basin Sub-basin Areas Sub Total -Asphalt/Concrete. Roof _Cinder, ;.Sand%Infield Mix ' GrassoreskiComposte' Bann Area Area Area Area ': Area Area Area: C Valiie. (Acres) (Sq.Ft.),6=0.90.. (Sq.FL) C=0.90 (Sq.FG),C=0.90 (Sq.,A),060.30 (Sq.Ft),:C=0.25 (Sq x�),C=0.15' w"C 11,891 4,144 07.3 CBI2 D 2S`; 11,383 736 ........... CB 11 006.`: 2,799 CB-to 4,477 :fl:90 k 0 18:: 7,822 1.&::, 3,939 3,202 797 C$6 . 0T}5.: 2,209 Or90 CBS 000.: :::OQO . CB 4a 0 14:. 2,529 3,463 CB4 037.:: 9,330 4,802 1,879 082:..::: 0 07:: 1,875 1,053 .0. CB 3b 019:: 7,080 1,030 CB3a ........` 479 CB ....4,955 2,372 474 CB 2a ` 018::: 4,955 2,372 474 0:86" CB 2 0 13: :: 4,787 938 374 686 SW roof 0 5.:: 15,125 Q,0..... NW r6of; 0 0S:: 3,662 0 90 •:0.0 1YE roof a 0:13::::: 5,796 79,652 39,206 18,211 Kennydale Elementary School Conveyance Analysis 3/26/2005 it r r r �r r� r r r r r it r �r r rr r r r r r CONVEYANCE SYSTEM ANALYSIS AND SIZING TABLE USING THE RATIONAL METHOD Location Sub Area C C*A Sum Tc i(R) I(R) W,- Pipe Typ. Slope Q(F) V V L Tt %d/D +�.k Basin (ac) C*A (min.) pia (in.) n (ft.ft.) (pipe (Pipe (at (ft.) (min.) From To Number nm full) full) Q(R)) CB 9 CB 10 9 0.18 0.90 0.16 0.16 6.3 0.80 2.73 11 8 0.014 1.0% 1.13 3.24 2.99 110 0.6 44.00% CB 10 CB 11 10 0.10 0.90 0.09 0.25 6.9 0.76 2.57 8 0.014 1.0% 1.13 3.24 3.32 70 0.4 55.00% CB 11 CB 12 11 0.06 0.90 0.06 0.31 7.3 0.73 2.49 `-7, 12 0.014 1.7% 4.33 5.51 4.11 70 0.3 29.00% CB 12 CB 13 12 0.28 0.86 0.24 0.55 7.5 0.71 2.43 ?�14_; 12 0.014 1.4% 3.92 4.99 4.49 93 0.3 40.50% CB 13 Vault CB 13 0.37 0.73 0.27 0.82 7.9 0.69 2.36 12 0.014 1.0% 3.32 4.23 4.38 10 0.0 55.00% CBI CB 2 CB 1 0.02 0.48 0.01 0.01 6.3 0.80 2.73 SQ;I _ 6 0.014 1.0% 0.52 2.65 1.57 65 0.7 16.00% CB 2a CB 2 CB 2a 0.18 0.86 0.15 0.15 7.0 0.75 2.56 el;. 6 0.014 1.0% 0.52 2.65 2.92 26 0.1 65.00% CB 2 CB 3 CB 2 0.13 0.79 0.10 0.27 7.1 0.74 2.52 '68 8 0.014 0.8% 0.97 g5.1 3.05 75 0.4 61.05% CB 3a CB 3 CB 3a 0.01 0.25 0.00 0.00 6.3 0.80 2.73f{31"' 6 0.014 2.4% 0.81 2.05 45 0.4 5.00% CB 3b CB 3 CB 3b 0.19 0.82 0.15 0.15 6.3 0.80 2.73 8 0.014 2.6% 1.81 4.23 42 0.2 32.50% CB 3c CB 3 CB 3c 0.07 0.67 0.04 0.04 6.3 0.80 2.73 a `=12 6 0.014 4.0% 1.04 3.59 31 0.1 23.00% CB 3 CB 4 3 0.18 0.86 0.15 0.62 7.5 0.72 2.43 12 0.014 0.8% 2.87 3.65 3.68 108 0.5 52.00% CB 4a CB 4 CB 4a 0.14 0.52 0.07 0.- 6.3 0.80 2.73 l y' 8 0.014 3.2% 2.01 5.76 3.70 42 0.2 21.00% CB 4 CB 5 4 0.37 0.82 0.30 1.00 8.0 0.69 2.33 12 0.014 0.8% 2.87 3.65 4.10 148 0.6 68.00% CB 5 Bioswale 5 0.00 600 0.00 1.00 8.6 0.65 2.23 12 0.014 1.0% 3.32 4.23 4.52 7 0.0 60.00% Bioswale CB 6 Bioswale 0.00 0.00 0.00 1.00 8.7 0.65 2.22 12 0.014 1.0% 3.32 4.23 4.51 40 0.1 60.00% CB 6 CB 7 6 0.05 0.90 1 0.05 1.04 8.8 0.65 2.20 12 0.014 1.0% 3.32 4.23 4.57 100 0.4 61.00% CB 7 Vault 7 0.18 0.83 0.15 1.20 9.2 0.63 2.14 $& `' 12 0.014 0.9% 3.15 4.01 1 4.50 53 0.2 68.00% SW roof NW roof SW roof 0.35 0.90 0.31 0.31 6.3 0.80 2.73 " 8 0.014 1.0% 1.13 3.24 3.56 94 0.4 65.00% NW roof NE roof NW roof 0.08 0.90 0.08 0.39 6.7 0.77 2.62 8 1 0.014 1.0% 1.13 3.24 3.67 115 0.5 74.00% NE roof Vault NE roof 0.13 0.90 0.12 0.51 7.3 0.73 2.49 .; 8 0.014 1.5% 1.38 3.95 4.48 81 0.3 75.50% Vault CB 8 Vault 0.00 0.00 0.00 0.00 6.3 0.00 0.00 12 0.014 1.0% 1 3.32 4.23 3.32 30 0.2 32.00% CB 8 Ex CB out 8 1 0.00 0.00 0.00 0.00 6.3 0.80 2.737_- 12 1 0.014 1 1.0% 1 3.32 4.23 3.32 24 0.1 32.00% Project: enny a e Elementary School R= ZLU P(R)= l Cafes by: B.S.B Job No: C040055-02 Location: Renton Washington Date: 3/28/2005 Page i Kennydale Elementary Conveyance Analysis-25 Year 3/28/2005 r �r �r �r r �r �r r �r r r �r r� r� r �r r �r r r �■ CONVEYANCE SYSTEM ANALYSIS AND SIZING TABLE USING THE RATIONAL METHOD Location Sub Area C C*A Sum Tc i(R) I(R) 1 R 1 Pipe Typ. Sloe F V V L TtBasin %d/D P Q( ) From To Number (ac) C*A (min.) '�£� (in.) n (ft.ft.) (pipe (pipe (at (ft.) (min.) s % full) full) Q(R)) CB 9 CB 1 9 0.18 0.90 0.16 0.16 6.3 0.80 3.14am-to" 8 0.014 1.0% 1.13 3.24 3.10 110 0.6 47.50% CB 10 CB 1 1 I 10 0.10 0.90 0.09 0.25 6.9 0.76 2.96 ORSR'': 8 0.014 1.0% 1.13 3.24 3.44 70 0.3 60.00% CB 11 CB 12 1I 0.CB 13 Vault 0.90 0,06 0.31 7.2 0.74 2.87 ;084N 12 0.014 1.7% 4.33 5.51 4.31 70 0.3 31.00% CB 12 a 12 0.28 0.86 0.24 0.55 7.5 0.72 2.80 ? f} ': 12 0.014 1.4% 3.92 4.99 4.64 93 0.3 44.00% ulItt CB 13 0.37 0.73 0.27 0.82 7.8 0.70 2.72 '<! 12 0.014 1.0% 3.32 4.23 4.54 10 0.0 60.00% CB 1 CB 2 CB 1 0.02 0.48 0.01 0.01 6.3 0.80 3.14 6 0.014 1.0% 0.52 2.65 1.65 65 0.7 17.00% CB 2a CB 2 CB 2a 0.18 0.86 0.15 0.15 7.0 0.75 2.94 Q .".` 6 0.014 1.0% 0.52 2.65 2.99 26 0.1 72.00% CB 2 CB 3 CB 2 0.13 0.79 0.10 0.27 7.1 0.74 2.90 7$ :, 8 0.014 0.8% 0.97 2.78 3.10 75 0.4 68.00% CB 3a CB 3 CB 3a 0.01 0.25 0.00 0.00 6.3 0.80 3.14 €Ilfl 6 0.014 2.4% 0.81 4.13 2.35 45 0.3 5.00% CB 3b CB 3 CB 3b 0.19 0.82 0.15 0.IS 6.3 0.80 3.14 60W,r1 8 0.014 2.6% 1.81 5.19 4.38 42 0.2 35.00% CB 3c CB 3 CB 3c 0.07 0.67 0.04 0.04 6.3 0.80 3.14 46 0.014 4.0% 1.04 5.30 1 3.66 31 0.1 25.00% CB 3 CB 4 3 0.18 0.86 0.15 0.62 7.5 0.72 2.80 1 5 12 0.014 0.8% 2.87 3.65 3,78 108 0.5 57.00% CB 4a CB 4 CB 4a 0.14 0.52 0.07 0.07 6.3 0.80 3.14 4(f 8 0.014 3.2% 2.01 5.76 3.97 42 0.2 22.00% CB 4 CB 5 4 0.37 0.82 0.30 1.00 8.0 0.69 2.69 12 0.014 0.8% 2.87 3.65 4.14 148 0.6 77.00% CB 5 Bioswale 5 0.00 0.00 0.00 1.00 8.6 0.66 2.57 12 0.014 1.0% 1 3.32 4.23 4.70 7 0.0 65.50% Bioswale CB 6 Bioswale 0.00 0.00 0.00 1.00 8.6 0.66 2.56 12 0.014 1.0% 1 3.32 4.23 4.69 40 0.1 65.50% CB 6 CB 7 6 0.05 0.90 0.05 1.04 8.7 0.65 2.53 12 0.014 1.0% 3.32 4.23 4.73 ]00 0.4 67.00% CB 7 Vault 7 0.18 0.83 0.15 1.20 9.1 0.63 2.47 O 12 0.014 0.9% 3.15 4.01 4.55 53 0.2 77.00% SW roof NW roof SW roof 0.35 0.90 0.31 0.31 6.3 0.80 3.14 0>g 8 0.014 1.0% 1.13 --3 24 3.64 94 0.4 72.00% NW roof NE roof NW roof 0.08 0.90 0.08 0.39 6.7 0.77 3.00 8 0.014 1.0% 1.13 3.24 3.34 115 0.6 99.90% NE roof Vault NE roof 0.13 0.90 0.12 0.51 7.3 0.73 2.85 1 '„ 8 0.014 1.5% 1.38 3.95 4.15 81 0.3 99.90% Vault CB 8 Vault 0.00 0.00 0.00 0.00 6.3 0.00 0.00 12 0.014 1.0% 3.32 4.23 4.00 30 0.1 45.00% CB 8 Ex CB out 8 0.00 0.00 0.00 0.00 6.3 0.80 3.14 12 0.014 1.0% 3.32 4.23 4.00 24 0.1 45.00% Project: Kenny a e Elementary SchoolR= P(R)= 10 Calcs by: B.S.B Job No: C040055-02 Location: Renton,Washington 00yj- Date: 3/28/2005 Page I Kennydale Elementary Conveyance Analysis-100 Year 3/28/2005 Appendix C ■ ■ ■ APPENDIX C ■ Geotechnical Report ■ i ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ COUGHLIN PORTER LUNDEEN Kennydale Elementary School ■ 24 Renton,Washington ■ CI V ED yk }' MAY ooa4 McGRANAHANar N--ts - -.J Associated { Earth Geotechnical Engineering n • Sciences , Inc .Subsurface Exploration, Geologic Hazards, and Preliminary Geotechnical Engineering-Report Water Resources PROPOSED REPLACEMENT r OF KENNYDALE r � ELEMENTARY SCHOOL Renton, Washington Solid and Hazardous Waste Prepared for ,4 Renton School District c/o. 1� Greene Gasaway Architects,-P.L.L.C. Project No. KE03330A Ecological/Biological Sciences October 7, 2003 ki. Geologic Assessments Associated Earth Sciences, Inc . October 7, 2003 Project No. KE03330A Renton School District c/o Greene Gasaway Architects, P.L.L.C. P.O. Box 4158 1 Federal Way, Washington 98063 Attention: Mr. Calvin Gasaway Subject: Subsurface Exploration, Geologic Hazards, and Preliminary Geotechnical Engineering Report Proposed Replacement of Kennydale Elementary School 1700 NE 28"' Street Renton, Washington Dear Mr. Gasaway: i ` We are pleased to present these copies of the referenced report. This report summarizes the results of our subsurface exploration, geologic hazards, and geotechnicnl engineering studies and offers recommendations for the preliminary design and development of the proposed project. Our recommendations are preliminary in that project plans are still under development at the time of this report. We have enjoyed working with you on this study and are confident that the recommendations presented in this report will aid in the successful completion of your project. If you should have any questions or if we can be of additional help to you, please do not hesitate to call. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington i 1 Kurt D. Merriman, P.E. 1 Principal Engineer KDM/Id/sn KE03330A2 Projeas\2003330\KE\WP-W2K 911 Fifth Avenue,Suite 100• Kirkland, WA 98033 • Phone 425 827-7701 • Fax 425 827-5424 SUBSURFACE EXPLORATION, GEOLOGIC HAZARDS, AND PRELIMINARY GEOTECHNICAL ENGINEERING REPORT �i PROPOSED REPLACEMENT OF KENNYDALE ELEMENTARY SCHOOL Renton, Washington ,I Prepared for: Renton School District c/o Greene Gasaway Architects, P.L.L.C. P.O. Box 4158 Federal Way, Washington 98063 Prepared by: Associated Earth Sciences, Inc. 911 5'' Avenue, Suite 100 Kirkland, Washington 98033 425-827-7701 Fax: 425-827-5424 I October 7, 2003 Project No. KE03330A i i I I Subsurface Exploration, Geologic Hazards, Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Project and Site Conditions ? I. PROJECT AND SITE CONDITIONS 1.0 INTRODUCTION ,! This report presents the results of our subsurface exploration and preliminary geotechnical engineering study for the proposed replacement of the Kennydale Elementary School located at 1700 NE 28 h Street, Renton,Washington. The location of the existing Kennydale Elementary School is shown on the Vicinity Map, Figure 1, included with this report. Our recommendations are preliminary in that project plans are still under development at the time of this report. The existing site features and approximate locations of the explorations accomplished for this study are presented on the Site and Exploration Plan, Figure 2. Once a site development plan is available, the conclusions and recommendations contained in this ,I report should be reviewed and modified, or verified, and additional recommendations presented as necessary. Additional subsurface explorations may be recommended once site development plans are finalized. I 1.1 Purpose and Scope The purpose of this study was to provide geologic and geotechnical design recommendations to be utilized in the preliminary design of the project. Our study included a review of available geologic literature, drilling exploration borings, and performing geologic studies to assess the type, thickness, distribution, and physical properties of the subsurface sediments and shallow ground water. Geologic hazard evaluations and geotechnical engineering studies were completed to establish preliminary recommendations for the type of suitable foundation, allowable foundation soil bearing pressure, anticipated foundation and floor settlement, floor support recommendations, drainage considerations, and flexible pavement design. This report summarizes our current fieldwork and offers hazard mitigation and preliminary development recommendations based on our present understanding of the project. We recommend that our office be allowed to review project plans as they near completion to verify that our geotechnical recommendations adequately address the project design. 1 1.2 Authorization Our work was completed in general conformance with the scope of work and cost presented in our proposal for the project dated June 17, 2003. We were authorized to proceed by Mr. Calvin Gasaway, Greene Gasaway Architects, P.L.L.C. This report has been prepared for the ■ exclusive use of the Renton School District, Greene Gasaway Architects, P.L.L.C., and their ■; agents for specific application to this project. Within the limitations of scope, schedule, and budget, our services have been performed in accordance with generally accepted geotechnical engineering and engineering geology practices in effect in this area at the time our report was October 7, 2003 ASSOCIATED EARTH SCIENCES, INC. I MT/ld/sn-KE03330A2-Projects120033301KEIWP-W2K Page 1 Subsurface Exploration, Geologic Hazards, Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Project and Site Conditions prepared. No other warranty, express or implied, is made. Our observations, findings, and opinions are presented as a means to identify and reduce the inherent risks to the owner. 2.0 PROJECT AND SITE DESCRIPTION This report is based on verbal information provided to us about this new project, as received from Greene Gasaway Architects, P.L.L.C. At the time this report was written, a new school building or buildings are planned to occupy the approximate location of the existing building and possibly the area within the southeast portion of the site. The existing playfield will remain and be used by the new school. Site development will also include new parking lots, fire lanes, bus lanes, and related utilities. We assume that the floor elevations of the new building or buildings would be similar to that of the existing grades and that no basements are anticipated. Conventional concrete and masonry construction methods are assumed, with light to moderate structural loads. For the purposes of this report, column loads on the order of 150 kips and wall loads of 3 to 5 kips per lineal foot are assumed. The project site is that of the existing Kennydale Elementary School located at 1700 NE 281h Street, Renton, Washington. The existing school consists of several buildings clustered at the southwest part of the site, with a new athletic field to the north and east, and parking lot and driveway areas on the south. The existing two-story main school building and the single-story gym are of masonry block construction. The three existing portable classrooms are single- story wood-frame structures. The site is relatively level and is situated a few feet higher in elevation than adjacent NE 30' Street. A rockery flanks the site along portions of the north and east property boundaries. Overall vertical relief across the site was visually estimated at less than 10 feet. 3.0 SUBSURFACE EXPLORATION Our field study included drilling 12 exploration borings and performing a geologic hazard reconnaissance to gain surface and subsurface information about the site. The various types of sediments, as well as the depths where characteristics of the sediments changed, are indicated i on the exploration logs presented in the Appendix. The depths indicated on the logs where conditions changed may represent gradational variations between sediment types in the field. If changes occurred between sample intervals in our exploration borings, they were interpreted. Our explorations were approximately located in the field by measuring from known site features shown on the site plan provided by Greene Gasaway Architects, P.L.L.C. Approximate exploration locations are shown on the attached Site and Exploration Plan, Figure 2. October 7, 2003 ASSOCIATED EARTH SCIENCES, INC. MT/Id/sn-KE03330A2-Projects120033301KEI WP-W2K Page 2 Subsurface Exploration, Geologic Hazards, Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Project and Site Conditions The conclusions and recommendations presented in this report are based on the 12 exploration borings completed for this study. The number, location, and depth of the explorations were completed within site and budget constraints. Because of the nature of exploratory work below ground, extrapolation of subsurface conditions between field explorations is necessary. It should be noted that differing subsurface conditions may sometimes be present due to the random nature of deposition and the alteration of topography by past grading and/or filling. The nature and extent of any variations between the field explorations may not become fully evident until construction. If variations are observed at that time, it may be necessary to re- evaluate specific recommendations in this report and make appropriate changes. 3.1 Exploration Borings The exploration borings were completed by advancing a hollow-stem auger with a track- mounted drill rig. During the drilling process, samples were obtained at generally 5-foot depth intervals. The exploration borings were continuously observed and logged by a geotechnical engineer from our firm. The exploration logs presented in the Appendix are based on the field logs, drilling action, and inspection of the samples secured. Disturbed but representative samples were obtained by using the Standard Penetration Test procedure in accordance with ASTM:D 1586. This test and sampling method consists of driving a standard 2-inch outside-diameter, split-barrel sampler a distance of 18 inches into the soil with a 140-pound hammer free-falling a distance of 30 inches. The number of blows for each 6-inch interval is recorded and the number of blows required to drive the sampler the final 12 inches is known as the Standard Penetration Resistance ("N") or blow count. If a total of 50 is recorded within one 6-inch interval, the blow count is recorded as the number of blows for the corresponding number of inches of penetration. The resistance, or N-value, provides a measure of the relative density of granular soils or the relative consistency of cohesive soils; these values are plotted on the attached exploration boring logs. The samples obtained from the split-barrel sampler were classified in the field and representative portions placed in watertight containers. The samples were then transported to our laboratory for further visual classification and laboratory testing, as necessary. i 4.0 SUBSURFACE CONDITIONS Subsurface conditions at the project site were inferred from the field explorations accomplished for this study and visual reconnaissance of the site. As shown on the field logs, the exploration borings encountered a silty sand with gravel in a dense to very dense, moist to wet condition interpreted as till which is considered to be suitable support strata. In each of the explorations, the till was covered by 2 to 13 feet of weathered till, recessional deposit soil, existing fill or October 7, 2003 ASSOCIATED EARTH SCIENCES, INC. MT/ld/sn-KE0333042-ProjectsW033MKEI WP-W2K Page 3 Subsurface Exploration, Geologic Hazards, Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Project and Site Conditions topsoil consisting of a mixture of silts and sands in a generally loose to medium dense, moist to wet condition. 4.1 Soil Conditions ,i Existing Fill Fill was encountered in exploration borings EB-1, EB-2, EB-3, EB-4, EB-8, and EB-10 to a depth of 7.5, 5, 5, 3, 2, and 3 feet, respectively. The fill consists of a mixture of silts and sands in a generally loose to medium dense, moist to wet condition. The existing fill was probably placed at the time the school was constructed. Since the quality, thickness, and compaction of the fill materials is relatively low or variable, the fill is considered unsuitable for structural support without remedial improvement. Additional exploration, delineation, and evaluation of the existing site fills may reveal material consistency and density suitable for the support of pavements and slabs with reasonable remedial improvement. For planning, the fill should not be considered suitable for foundation support in its present condition. Recessional Outwash Exploration borings EB-4, EB-9, EB-10, EB-11, and EB-12 encountered between 41/2 and 13 feet of sandy soil in a loose to medium dense, moist to wet condition interpreted as recessional outwash. The recessional deposits accumulated in meltwater streams during the retreat of the Vashon age glacier from the region. Based on its relatively low density the recessional deposit soil is not considered suitable for direct support of structures without remedial improvement. The recessional deposit soil should be suitable for pavement support after reasonable remedial work is conducted. Till Below the fill/recessional outwash soil, our exploration borings encountered silty sand with gravel interpreted as till. The upper portion of the till encountered (to a depth of 7.5 feet, maximum) was observed to be in a weathered, medium dense condition. Unweathered till was observed to be in a dense to very dense condition. The weathered till and the upper portion of the unweathered till was observed to be moist to wet. Till was deposited at the base of an active continental glacier and was subsequently overridden and compacted by the weight of the overlying glacial ice. Till soils typically possess high strength and low compressibility characteristics that are favorable for structural support. Till soils typically contain a substantial fine-grained soil fraction, which makes them moisture-sensitive and susceptible to disturbance when wet site or weather conditions exist. October 7, 2003 ASSOCIATED EARTH SCIENCES, INC. ,', MT/ld/sn-KE03330A2-Projects120033301KEIWP-W2K Page 4 i - Subsurface Exploration, Geologic Hazards, Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Project and Site Conditions i E 4.2 Hydrology Relatively high moisture contents were observed for soil at or near the contact between the surface soils and the underlying till in all but exploration borings EB-1, EB-5, and EB-6. This high moisture was interpreted to represent a perched ground water condition where downward infiltration of surface water is impeded by lower permeability, dense till at depth. It should be noted that the exploration borings were completed near the middle of a relatively dry summer following a drier than normal spring and winter._ Ground water levels are expected to be higher and the amount of ground water is expected to be greater during and following the wetter winter and spring seasons. The quantity and duration of flow from an excavation face ethat pierces the perching layer will depend on the soil grain size, topography, and season. Ground water conditions should also be expected to vary in response to changes in seasonal precipitation, on- and off-site land usage, and other factors. 4.3 Site Infiltration Infiltration testing has not been conducted as part of our scope of work. Based on our observation of strata encountered at the site, the recessional outwash soil encountered in EP-4 located within the western portion of the site and in EP-9, EP-10, EP-11, and EP-12 located within the eastern portion of the site is the only strata that might allow infiltration for site rdrainage disposal. The till encountered at the site is considered impermeable from an infiltration standpoint. Once you have determined the approximate area for your drainage pond(s)/vault(s), we can conduct infiltration testing and provide recommendations regarding the soil infiltration rate, ground water mounding, and downstream "fate" analysis. i i October 7, 2003 ASSOCIATED EARTH SCIENCES, INC. MT/!d/sn-KE03330A2-Projeas120033301KE1WP-W2K Page 5 i Subsurface Exploration, Geologic Hazards, Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Geologic Hazards and Mitigations II. GEOLOGIC HAZARDS AND MITIGATIONS The following discussion of potential geologic hazards is based on the geologic, slope, and ground and surface water conditions as observed and discussed herein. The discussion will be ,! limited to seismic issues, landslides or mass-wasting, and erosion, including sediment transport and should be considered preliminary. 5.0 SEISMIC HAZARDS AND RECOMMENDED MITIGATION Earthquakes occur in the Puget Sound Lowland with great regularity. The vast majority of these events are small and are usually not felt by people. However, large earthquakes do occur as evidenced by the most recent 6.8-magnitude event on February 28, 2001 near Olympia Washington, the 1965, 6.5-magnitude event, and the 1949, 7.2-magnitude event. The 1949 earthquake appears to have been the largest in this area during recorded history. Evaluation of return rates indicates that an earthquake of the magnitude between 5.5 and 6.0 is likely within a given 20-year period. Generally, there are four types of potential geologic hazards associated with large seismic events: 1) surficial ground rupture; 2) seismically induced landslides; 3) liquefaction; and 4) ground motion. The potential for each of these hazards to adversely impact the proposed project is discussed below. 5.1 Surficial Ground Rupture The nearest known fault trace to the project site is the Seattle Fault mapped approximately 5 to 6 miles to the north of the site. Recent studies by the U.S. Geological Survey (USGS) (e.g., Johnson et al., 1994, Origin and Evolution of the Seattle Fault and Seattle Basin, Washington, Geology, v. 22, pp. 71-74; and Johnson et al., 1999, Active Tectonics of the Seattle Fault and Central Puget Sound Washington - Implications for Earthquake Hazards, Geological Society of America Bulletin, July 1999, v. 111, n. 7, pp. 1042-1053) have provided evidence of surficial ground rupture along a northern splay of the Seattle Fault. The recognition of this fault splay is relatively new and data pertaining to it are limited with the studies still ongoing. According to the USGS studies, the latest movement of this fault was about 1,100 years ago when about 20 feet of surficial displacement took place. This displacement can presently be seen in the form of raised, wave-cut beach terraces along Alki Point in West Seattle and Restoration Point at the south end of Bainbridge Island. The recurrence interval of movement along these fault systems is still unknown, although it is hypothesized to be in excess of several thousand years. Due to the suspected long recurrence interval, the potential for surficial ground rupture is considered to be low during the expected life of the proposed structure. October 7, 2003 ASSOCIATED EARTH SCIENCES, INC. MT/Ld/sn-KE03330A2-Projects120033301KEIWP-W2K Page 6 Subsurface Exploration, Geologic Hazards, Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Geologic Hazards and Mitigations 5.2 Seismically Induced Landslides The potential risk of damage to new structures by a seismically induced landslide is considered to be low due to lack of steep slopes on the project site. j 5.3 Liquefaction Liquefaction is a process through which unconsolidated soil loses strength as a result of vibratory shaking, such as that which occurs during a seismic event. During normal conditions, the weight of the soil is supported by both grain-to-grain contacts and by the pressure within the pore spaces of the soil below the water table. Extreme vibratory shaking can disrupt the grain-to-grain contact, increase the pore pressure, and result in a decrease in soil shear strength. The soil is said to be liquefied when nearly all of the weight of the soil is supported by pore pressure alone. Liquefaction can result in deformation of the sediment and settlement of overlying structures. Areas most susceptible to liquefaction include those areas underlain by non-cohesive silt and sand with low relative densities, accompanied by a shallow water table. The encountered stratigraphy has a low potential for liquefaction due to hi gh density of most of the site soils, and typically high silt content. We did not complete a rigorous liquefaction analysis and none is recommended. 5.4 Ground Motion The project site is located within a Zone 3 rating for seismic activity on a scale of 1 (lowest) to 4 (highest) based on the Seismic Zone Map of the United States, Figure No. 16-2 in the 1997 edition of the Uniform Building Code (UBC). This zonation is based on past earthquake activity in the Puget Sound region. As such, design recommendations in the report accommodate the possible effect of seismic activity in areas with a Zone 3 rating, corresponding to a peak ground acceleration of 0.3g (a Richter magnitude 7.5 earthquake occurring directly beneath the site), in accordance with UBC guidelines. This seismic zone factor for this site should be used with soil type Sc. Alternatively, guidelines presented in the 2000 International Building Code (IBC) may be used. Information presented in Figure 1615(1) indicate a mapped spectral acceleration for short periods of S, = 1.5. Information presented in Figure 1615(2) indicates a mapped spectral acceleration for 1 second period of Si = 0.5. Based on the results of subsurface exploration and on an estimation of soil properties at depth utilizing available geologic data, Site Class "C" in conformance with Table 1615.1.1 may be used. Site coefficients Fa = 1.0 and F, = 1.3 in conformance with IBC Tables 1615.1.2 (1) and 1615(2), respectively, may be used. i October 7, 2003 ASSOCIATED EARTH SCIENCES, INC. MT/ld/sn-KE03330A2-Projects120033301KEIWP-W2K Page 7 Subsurface Exploration, Geologic Hazards, Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton Washington Geologic Hazards and Mitigations 6.0 EROSION HAZARDS AND MITIGATION ■ To mitigate and reduce the erosion hazard potential and off-site soil transport during and post- construction, we recommend the following: 1. No water should be directed to flow over cuts/slopes during construction activities. 2. All storm water from impermeable surfaces should be tightlined into an approved storm water drainage system or temporary storage facilities and should never be allowed to flow over site cuts/slopes. 3. To reduce the amount of soil transport during site grading, silt fences should be placed along the lower elevations of the construction area. 4. Construction should proceed during the drier periods of the year, if possible, and disturbed areas should be revegetated as soon as possible. 5. Ground water seepage should be anticipated during site grading. Seepage should be controlled and tightlined into a suitable collection system and disposed of into an approved storm water drainage system or temporary storage facility. Specific seepage recommendations related to erosion and/or slope stability hazards are best developed in the field at the time of construction, when the actual seepage conditions can be observed. 6. Soils which are to be reused around the site should be stored in such a manner as to reduce erosion. Protective measures may include, but are not necessarily limited to, covering with plastic sheeting or the use of straw bales/silt fences. Soils excavated for foundation walls should not be placed on sloped areas or within 15 feet of the crest of a temporary cut. I October 7, 2003 ASSOCIATED EARTH SCIENCES, INC. MT/ld/sn-KE0333OA2-Projects120033301KEIWP-W2K Page 8 Subsurface Exploration, Geologic Hazards, Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations III. PRELIMINARY DESIGN RECOMMENDATIONS 7.0 INTRODUCTION Our exploration indicates that, from a geotechnical standpoint, the proposed project is compatible with this site provided the recommendations contained herein are properly followed. The depth to bearing soils is expected to vary across the site from near the ground surface to as deep as 7.5 feet. The foundation bearing strata can be assumed to be either the undisturbed till or the recessional outwash sand following recompaction. The till soils were encountered near surface within EB-5, EB-6, EB-7, and within 2 feet of ground surface in EB- 8. Elsewhere on the site, the depth to till soil ranges between 5 and 13 feet below existing ground. Fill soils were encountered to depths of 2 to 7.5 feet below the existing surface. The fill is not suitable for foundation support. The recessional outwash is a suitable bearing stratum only after recompaction as recommended in this report. With the exception of the soil in exploration pits EP-1, EP-5, and EP-6, relatively shallow perched ground water was encountered near the contact between the till and overlying soil. Reuse of the higher moisture soil encountered near the soil/till contact as structural fill during all but the driest times of the year may be difficult. Conventional shallow foundations and slab-on-grade floors may be used with normal site preparation procedures where suitable foundation bearing soils are encountered near foundation elevation. Careful site development planning will be required to identify fill soils that require removal and outwash soils that only require recompaction. The unsuitable fill soil must be removed from beneath planned foundations, floor slabs, and any other settlement-sensitive rstructures. An alternative to fill removal would be to use short aggregate piers (Geopiers") or rock trenches to support building foundations through areas underlain by existing fill soils. Due-to the limited and variable thickness of existing fills, these alternatives are probably not warranted. We can provide specific recommendations for these alternatives if requested. The following report sections present our specific geotechnical site development recommendations. 8.0 SITE PREPARATION All foundations, paving, and other structures that exist under the planned building and pavement areas should be removed. Any buried utilities should be removed or relocated if they are under the proposed buildings. The resulting depressions should be backfilled with structural fill as discussed under the Structural Fill section. In development areas that are currently occupied by landscaping, all vegetation and topsoil should be removed during site preparation. r October 7, 2003 ASSOCIATED EARTH SCIENCES, INC. MT/ld/sn-KE03330A2-Projects120033301KEIWP-W2K Page 9 Subsurface Exploration, Geologic Hazards, Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations Excavations to achieve design building subgrades should then be completed. The exposed subgrade soils should be evaluated. Where exposed, the existing fill soil should be removed to expose either recessional outwash soils or firm, unyielding till. The removal of existing unsuitable soil should extend laterally beyond the building footprint a distance equal to the depth of unsuitable soil below planned foundations or floor slab. For example, if unsuitable soil extends 3 feet below planned foundations at a given point, the overexcavation lateral limit should extend 3 feet beyond the building./If recessional outwash soils are encountered after existing fill removal, the surface of the outwash soils should be compacted to 95 percent relative compaction as recommended in the Structural Fill section of this report. If till soils are encountered after existing fill is removed, no further excavation or compaction is required. Once suitable native soils have been reached, structural fill can be placed to restore the design building subgrade elevation. For pavement areas, complete existing fill removal is not required. Once a subgrade elevation has been established, the surface of the subgrade should be proof-rolled with a loaded dump truck. Any soft or loose areas should be removed to expose a suitable, firm condition and the overexcavation backfilled with properly compacted structural fill. This procedure should be completed subsequent to site stripping and prior to j placing new fills to raise site grades. Structural fill material should be selected and placed in accordance with recommendations in the Structural Fill section of this report. If construction will occur during winter weather conditions, we recommend that the upper 6 to 12 inches of the building pad consist of railroad ballast, crushed concrete, or sand and gravel that contains less than 5 percent passing the U.S. No. 200 sieve, based on that fraction passing the U.S. No. 4 sieve. The purpose of this select fill is to provide a working surface that is compatible with moderately wet site and weather conditions. Depending on field conditions, geotextile fabric, such as Mirafi 50OX or equivalent, might be needed beneath areas where heavy traffic is expected. In our opinion, stable construction slopes should be the responsibility of the contractor and should be determined during construction. For estimating purposes, however, we anticipate that temporary, unsupported cut slopes in the existing fill/recessional outwash soil can be made at a slope of 1.5H:1V (Horizontal:Vertical). Temporary, unsupported cuts in till can be made at a slope of 1H:1V or flatter. These slope angles assume that ground water seepage is not strong enough to reduce slope stability and that surface water is not allowed to flow across the temporary slope faces. If ground or surface water is present when the temporary excavation slopes are exposed, flatter slope angles will be required. As is typical with earthwork operations, some sloughing and raveling may occur and cut slopes may have to be adjusted in the field. In addition, WISHA/OSHA regulations should be followed at all times. We should be allowed to review excavation cut slopes greater than 8 feet in height. Permanent cut slopes should be no steeper than 2H:IV. Some of the on-site soils contain a high percentage of fine-grained material, which makes them j moisture-sensitive and subject to disturbance when wet. The contractor must use care during October 7, 2003 ASSOCIATED EARTH SCIENCES, INC. MT/ld/sn-KE03330A2-Projects 120033301KEI WP-W2K Page 10 Subsurface Exploration, Geologic Hazards, Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations ,I site preparation and excavation operations so that the underlying soils are not softened. If disturbance occurs, the softened soils should be removed and the area brought to grade with structural fill. To the extent that it is possible, we recommend that the existing paving along the west or north portion of the site be used for construction staging. If the existing pavement cannot be used for construction staging, we recommend that crushed rock fill be considered in construction staging areas to form a working surface. If crushed rock is to be used for the access and staging areas, it should be underlain by engineering stabilization fabric such as Mirafi 50OX or equivalent to reduce the potential of fine-grained materials pumping up through the rock and turning the area to mud. The fabric will also aid in supporting construction equipment, thus reducing the amount of crushed rock required. We recommend that at least 10 inches of rock ■ be placed over the fabric; however, due to the variable nature of the near-surface soils and ■ differences in wheel loads, this thickness may have to be adjusted by the contractor in the field. 9.0 STRUCTURAL FILL Structural fill will be necessary to establish desired grades and to provide a uniform subgrade below new floor slabs and pavement areas. All references to structural fill in this report refer to subgrade preparation, fill type, and placement and compaction of materials as discussed in this section. If a percentage of compaction is specified under another section of this report, the value given in that section should be used. Building areas should be evaluated after site stripping. Existing fill soils should be overexcavated to expose either outwash soils or till. Below pavements, the stripped subgrade should be proof-rolled and loose or soft areas overexcavated to expose firm subgrade soils. After stripping, excavation, and any required overexcavation has been performed to the satisfaction of the geotechnical engineer/engineering geologist, the upper 12 inches of exposed ground should be recompacted to 95 percent of the modified Proctor maximum density using ASTM:D 1557 as the standard or to a firm unyielding condition. If the subgrade contains too much moisture, adequate recompaction may be difficult or impossible to obtain and should probably not be attempted. In lieu of recompaction, the area to receive fill should be blanketed with washed rock or quarry spalls to act as a capillary break between the new fill and the wet subgrade. Where the exposed ground remains soft and further overexcavation is impractical, placement of an engineering stabilization fabric may be necessary to prevent contamination of the free-draining layer by silt migration from below. After recompaction of the exposed ground is tested and approved, or a free-draining rock course is laid, structural fill may be placed to attain desired grades. Structural fill is defined as October 7, 2003 ASSOCIATED EARTH SCIENCES, INC. MT/td/stt-YE03330A2-Projects 12003330WEI WP-W2K Page 11 Subsurface Exploration, Geologic Hazards, Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations non-organic soil, acceptable to the geotechnical engineer, placed in maximum 8-inch loose lifts with each lift being compacted to 95 percent of the modified Proctor maximum density using ASTM:D 1557 as the standard. In the case of roadway and utility trench filling, the backfill should be placed and compacted in accordance with current local or county codes and standards. The top of the compacted fill should extend horizontally outward a minimum distance of 3 feet beyond the location of the perimeter footings or roadway edge before sloping down at an angle of 2H:1V. The contractor should note that any proposed fill soils must be evaluated by Associated Earth Sciences, Inc. (AESI) prior to their use in fills. This would require that we have a sample of the material 72 hours in advance of filling activities to perform a Proctor test and determine its field compaction standard. Soils in which the amount of fine-grained material (smaller than the No. 200 sieve) is greater than approximately 5 percent (measured on the minus No. 4 sieve size) should be considered moisture-sensitive. The on-site till and outwash soils generally contained substantial amounts of silt and are considered highly moisture-sensitive. These materials are acceptable for use as fill provided they are placed and compacted at a moisture content that allows for the minimum specified compaction presented in this report. Reuse of till soils during wet site or weather conditions is expected to be difficult or impossible due to high silt content and moisture sensitivity. The outwash soils should perform better under a wider range of moisture contacts than the siltier till soils. Use of moisture-sensitive soil in structural fills should be limited to favorable dry weather conditions. A portion of the existing fill/recessional outwash soil on-site was observed to have elevated moisture content and may not be considered suitable for use in structural fill applications. Free-draining fill can be used in wetter site and weather conditions under a wider range of moisture conditions than the on-site soils. Free-draining fill consists of non-organic soil with the amount of fine-grained material limited to 5 percent by weight when measured on the minus No. 4 sieve fraction and containing at least 25 percent greater than the No. 4 sieve. In dry weather, inorganic on-site soils can be used as structural fill if they are cleaned of woody debris and oversized rocks. We recommend that during construction, traffic across exposed site soils should be kept to a minimum during and after storm events, until the surface drains. When these materials are wet, it may result in disturbance of the otherwise firm stratum, requiring removal and replacement of disturbed soils. If wet weather construction is expected, construction access and staging areas should be protected as described in the Site Preparation section of this report. j A representative from our firm should inspect the stripped/overexcavated subgrade and be present during placement of structural fill to observe the work and perform a representative number of in-place density tests. In this way, the adequacy of the earthwork may be evaluated as filling progresses and any problem areas may be corrected at that time. It is important to October 7, 2003 ASSOCIATED EARTH SCIENCES, INC. MT/ld/sn-KE03330A2-Projects120033301KEIWP-W2K Page 12 Subsurface Exploration, Geologic Hazards, Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations understand that taking random compaction tests on a part-time basis will not assure uniformity or acceptable performance of a fill. As such, we are available to aid the owner in developing a suitable monitoring and testing program. 10.0 FOUNDATIONS Spread footings may be used for building support when founded on suitable till, recompacted outwash soils, or structural fill placed as previously discussed. To limit differential settlements between footings that bear on structural fill or outwash soils and those that bear on dense till, we recommend that an allowable foundation soil bearing pressure of 2,500 pounds per square foot (pso be utilized for design purposes, including both dead and live loads. If higher bearing pressures are needed, a value of 5,000 psf may be used in areas where all footings are placed entirely on dense till. An increase of one-third may be used for short-term wind or seismic loading. Perimeter footings should be buried at least 18 inches into the surrounding soil for frost protection; interior footings require only 12 inches burial. However, all footings must penetrate to the prescribed bearing stratum and no footing should be founded in or above loose, organic, or existing fill soils. It should be noted that the area bounded by lines extending downward at 1H:1V from any footing must not intersect another footing or intersect a filled area which has not been compacted to at least 95 percent of ASTM:D-1557. In addition, a 1.5H:1V line extending down from any footing must not daylight because sloughing or raveling may eventually undermine the footing. Thus, footings should not be placed near the edge of steps or cuts in the bearing soils. Anticipated settlement of footings founded as described above should be on the order of 3/a ■ inch or less. However, disturbed soil not removed from footing excavations prior to footing ■ placement could result in increased settlements. All footing areas should be inspected by AESI prior to placing concrete to verify that the design bearing capacity of the soils has been attained and that construction conforms to the recommendations contained in this report. The governing municipality may require such inspections. Perimeter footing drains should be provided as discussed under the section on Drainage Considerations. I i 11.0 LATERAL WALL PRESSURES i Walls that are free to yield laterally at least 0.1 percent of their height should be designed using "active" equivalent fluid pressures. Fully restrained, rigid walls that cannot yield should be designed using "at-rest" equivalent fluid pressures. The following table provides appropriate active, at-rest, and passive equivalent fluid pressures (and associated friction coefficients) for the anticipated project wall design conditions. October 7, 2003 ASSOCIATED EARTH SCIENCES, INC. MT/Id/sn-KE03330A2-Projects 120033301KEIWP-W2K Page 13 Subsurface Exploration, Geologic Hazards, Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations Active Equivalent At-Rest Passive ■ Fluid Equivalent Equivalent Backslope Conditions Pressure Fluid Fluid Friction Rock/Soil Type (Horizontal:Vertical) (pcf)* Pressure (pcf) Pressure (pcf) Coefficient Till Horizontal 30 50 350 0.35 Till 2H:1V maximum 60 75 350 0.35 Structural fill or Horizontal 35 55 300 0.30 outwash soils Structural fill or 2H:1 V maximum 65 80 300 0.30 outwash soils *pcf= pounds per cubic foot All backfill behind walls or around foundation units should be placed as per our recommendations for structural fill and as described in this section of the report. Where cast- in-place retaining walls face structural fill, the backfill should consist of on-site or imported granular fill, compacted to 90 percent of ASTM:D 1557. A higher degree of compaction is not recommended, as this will increase the pressure acting on the wall. A lower compaction may result in settlement of slab-on-grades or other improvements placed above the walls. Thus, the compaction 'level is critical and must be tested by our firm during placement. Surcharges from adjacent footings, heavy construction equipment, or sloping ground (where not indicated) must be added to the above values. Perimeter footing drains should be provided for all retaining walls as discussed under the section on Drainage Considerations. It is imperative that proper drainage be provided so that hydrostatic pressures do not develop against the wall. This would involve installation of a minimum 1-foot-wide washed gravel blanket drain, which is continuous with the perimeter footing drain and extends to within 1 foot of the ground surface. Lateral loads can be resisted by friction between the foundation and the till, supporting structural fill, or by passive earth pressure acting on the buried portions of the foundations. The foundations must be backfilled with structural fill, compacted to at least 95 percent of the maximum dry density, to achieve the minimum passive resistance shown in the table for footings cast against structural fill. The presented values are allowable and include a safety factor of at least 1.5. I I 12.0 FLOOR SUPPORT i Slab-on grade floors should be constructed above either recompacted outwash soils, new structural fill, or above till as described in the Site Preparation section of this report. All fill beneath the slab must be compacted to at least 95 percent of ASTM:D 1557. The floor should be cast atop a minimum of 4 inches of washed granulithic material or pea gravel to act as a October 7, 2003 ASSOCIATED EARTH SCIENCES, INC. MT/!d/sn-KE03330A2-Projects120033301KEI WP-W2K Page 14 Subsurface Exploration, Geologic Hazards, Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations capillary break. Areas of slab subgrade that are disturbed (loosened) during construction should be compacted to a non-yielding condition prior to placement of capillary break material. It should also be protected from dampness by an impervious moisture barrier at least 10 mils thick. The impervious barrier should be placed between the capillary break material and the concrete slab. The American Concrete Institute recommends placing a 2-inch layer of clean sand above the vapor barrier to protect it from damage and aid in curing of the concrete. If this sand layer is used, it must be protected from precipitation or allowed to thoroughly dry out prior to pouring the concrete slab. 13.0 DRAINAGE CONSIDERATIONS It is possible that ground water or seepage may be encountered at depths required for normal construction during the wetter months of the year. Therefore, the contractor should be prepared to provide temporary storm water collection, storage, and disposal mechanisms as necessary prior to site work and during construction. All retaining and footing walls should be provided with a drain at the footing elevation. Drains should consist of rigid, perforated, PVC pipe surrounded by washed pea gravel. The level of the perforations in the pipe should be set at the bottom of the footing at all locations and the drain collectors should be constructed with sufficient gradient to allow gravity discharge away from the building. In addition, all retaining walls and modular block walls should be lined with a minimum 12-inch-thick washed gravel blanket provided to within 1 foot of the top of wall, and which ties into the footing drain. Modular block walls if used should also be provided with chimney drains. Roof and surface runoff should not discharge into the footing drain system but should be handled by a separate, rigid, tightline drain. In planning, exterior grades adjacent to walls should be sloped downward away from the structure to achieve surface drainage. 14.0 PAVEMENT RECOMMENDATIONS At this time, site layout has not been completed sufficiently to determine what types of soil are likely to be encountered at planned pavement subgrades. Pavement subgrade can consist of I either recompacted existing fill, recompacted outwash soils or till. Pavement design will depend to some extent on the soil that exists beneath the area to be paved. If paving is planned above areas of existing fill/recessional outwash soil we recommend that the subgrade be proof- rolled to expose soft areas and then compacted to 95 percent compaction after the removal and repair of soft areas or organic soils. The areas to be paved should be proof-rolled with a loaded dump truck or other suitable equipment under the observation of the geotechnical engineer. Any soft, loose, or yielding October 7 2003 ASSOCIATED EARTH SCIENCES, INC. MT/ld/sn--KE03330A2-Projects120033301KE1 WP-W2K Page 15 Subsurface Exploration, Geologic Hazards, iProposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations areas or significantly organic soils identified by proof-rolling should be repaired prior to further work. After proof-rolling, paving subgrades should be compacted to 95 percent of the modified Proctor maximum dry density as determined by ASTM:D 1557 and to a firm, unyielding condition. Following subgrade preparation, we recommend a passenger car pavement section consisting of a 21/2-inch compacted asphalt Raving above a 4-inch compacted crushed rock base. In areas where buses, garbage trucks, fire trucks, delivery trucks, or other Jheavy vehicles will be driven or parked, we recommend a paving section consisting of 4 inches of asphalt paving above 6 inches of crushed rock base. Pavement thickness design is a compromise between higher initial cost with longer design life and lower maintenance, and lower initial cost with higher maintenance requirements and shorter design life. The recommended pavement sections are intended to provide a 20-year service life with normal maintenance. Normal maintenance typically includes periodic sealing, i and at least one renovation that includes repair and overlay of damaged areas. 15.0 PROJECT DESIGN AND RECOMMENDATIONS FOR FURTHER STUDY r At the time of this report, site grading, structural plans, and construction methods have not been finalized and the recommendations presented herein are preliminary. We are available to provide additional geotechnical consultation and exploration as the project design develops and possibly changes from that upon which this report is based. We recommend that AESI perform a geotechnical review of the plans prior to final design completion. In this way, our earthwork and foundation recommendations may be properly interpreted and implemented in the design. We are also available to provide geotechnical engineering and monitoring services during construction. The integrity of the foundation depends on proper site preparation and construction procedures. In addition, engineering decisions may have to be made in the field in the event that variations in subsurface conditions become apparent. Construction monitoring services are not part of this current scope of work. If these services are desired, please let us know and we will prepare a cost proposal. October 7, 2003 ASSOCIATED EARTH SCIENCES, INC. MT/td/sn-KE03330A2-Projects 120033301KEIWP-W2K Page 16 Subsurface Exploration, Geologic Hazards, ■ Proposed Replacement of Kennydale Elementary School and Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations We have enjoyed working with you on this study and are confident that these recommendations will aid in the successful completion of your project. If you should have any questions, or require further assistance, please do not hesitate to call. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington � ME]? WAS 23580 !S'TERO SfONAL EI(PIRES 1�/2O/ Maire Thornton, P.E. r erriman, P.E. 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' r�'a ia.• QZ �. .�� -.\�:... ..`/ j•,.^.i/,i!,�~ j,�y^�}� (� J, ��r i/.!- v � � i 7 -i 4.. \ 1 ti ' a i a ti��_• �r r a' 1 - � ^t C�.'�•\��, �I r /I r "t� I t! � �. f >/rF. /T r J j i t �' J� _ •�0-�'?"Z - ^\ r , �-•�i ,--t, }ir-vl6/ , �`. i 1r'X 1 l % ./ ,., r � e + 1 a ;l/f1� •Zdv?•'f;•%/ f 1 ' - l E f�..�„`'`�� \ 15 ti�F'�•�`-1'-%=;-� "�'\� f ,r1�J fr�� � r � � �r,� `�,`� J�'\ •,�,* ,� � r. /• tr �.��� \ , m.� , 'Pack -��.; ��s ;,,1 _ Jw �i� ,. *.� �'` it f i � J �J;'•` „`�\' r ,� '� �.. w .r "a'yt``. a, i••.,,,Jf ,� �L I ,i !' +y /1 I �`.. r y -_ ,i, a I;. r .. .s �. _ `"�'.-�.. _;\ �°�L..R S r' i .,r ''� _ l •r !1'I,x'.., TNt JMN o 1/2 1 M E > By? ®0 FEET 0 SOOm 1000m 'J V Printed fmmTOPOI 01998 Wildflower Productions(www.topo.com) 0 E m m vAssociated Earth Sciences, Inc. FIGURE 1 T VICINITY MAP ® ® i � ® KENNYDALE ELEMENTARY DATE 08/03 RENTON, WASHINGTON PROJ.NO. KE03330A 0 _ .. I ! EB-1 I I I • I • I I I I _ Existing E13-4 I Main Building I I I ! I I I I I : I • I I I EB-5 I Existing I Gymnasium Existing Play Shed i I EB-3 - I � I I • •E13-6 i I EB-2 i I N W Z Existing Portables / I • � I EB-7 i I EB-10 • EB-12 I ' I EB-11 EB 8 1cK9�50 �� .• ' ' yell I � . I EB-9 i I LEGEND N EB-9 • Approximate location of exploration boring Jr NO SCALE Reference: Map supplied by client d FIGURE 2 Associated Earth Sciences, Inc. SITE AND EXPLORATION PLAN ® ® n ® KENNYDALE ELEMENTARY SCHOOL DATE 08/03 L� RENTON, WASHINGTON PROJ. NO. KE03330A r� 0 ° ° a o Well graded gravel and Terms Describing Relative Density and Consistency cc o°o^ GW gravel with sand, little to DensitySPT(�lblows/foot ° 0 0 no fines Very Loose 0 to 4 j o D o 0 0 o Coarse- Loose 4 to 10 > p N -0 0 0 0 0 Poorly-graded gravel Grained Soils Medium Dense 10 to 30 l U Cn wo'o'o GP Test Symbols '0 0 0 0 and gravel with sand, Dense 30 to 50 o o 0 0 0 0 0 Very Dense >50 G =Grain Size little to no fines N o Z o 0 0 o M= Moisture Content 6 CD o ° o° o Consistency SPT(�)blows/foot A=Atterberg Limits Silty gravel and silty Very Soft 0 to 2 C=Chemical m �°'�' gravel with sand Fine- Soft 2 to 4 DD= Dry Density o r C h ° ° GM � c ° 0° 0 Grained Soils Medium Stiff 4 to 8 K=Permeability C ii � g � aFA Stiff 8 to 15 N r Clayey gravel and Very Stiff 15 to 30 GC clayey gravel with sand Hard >30 c9 Component Definitions M o Well-graded sand and Descriptive Term Size Range and Sieve Number Sw sand with gravel, little Boulders Larger than 12" o to no fines Cobbles 3"to 12" LL ` .- Gravel 3"to No.4(4.75 mm) Poorly-graded sand Coarse Gravel 3"to 3/4" m > � . U) cj .12 vu SP and sand with gravel, Fine Gravel 3/4"to No.4(4.75 mm) m v little to no fines Sand No.4(4.75 mm)to No.200(0.075 mm) z Coarse Sand No.4(4.75 mm)to No.10(2.00 mm) a _ Silty sand and Medium Sand No. 10(2.00 mm)to No.40(0.425 mm) 12 H sM silty sand with Fine Sand No.40(0.425 mm)to No.200(0.075 mm) (0 ca N U o o LL _ gravel Silt and Clay Smaller than No.200(0.075 mm) Clayey sand and (s) SC Estimated Percentage Moisture Content ^u - clayey sand with gravel Percentage by Dry-Absence of moisture, Component dusty,dry to the touch Weight Silt,sandy silt,gravelly silt, Trace <5 Slightly Moist-Perceptible ar C) ML silt with sand or gravel Few 5 to 10 moisture > Little 15 to 25 Moist-Damp but no visible in U m With Non-primary coarse water o -m m constituents: > 15% Very Moist-Water visible but Clay of low to medium — ry d a ) plasticity; silty, sandy,or -Fines content between not free draining m C� 5%and 15% Wet-Visible free water,usual) gravelly clay, lean clay Y Jfrom below water table N aN Organic clay or silt of low Symbols 2 OL plasticity Blows/6"or 0 Sampler portion of 6" Cement grout o Type / surface seal Elastic silt,clayey silt,silt / Sampler Type 2.0"OD s entonite with micaceous or ?s Description o �, MH Split-Spoon m p A4) seal L0 diatomaceous fine sand or y 0 silt Sampler 3.0"OD Split-Spoon Sampler Filter pack with o (SPA 3.25"OD Split-Spoon Ring Sampler (.) ; : blank casing o Clay of high plasticity, : section o C) Bulk sample ar c r CH sandy or gravelly clay,fat 3.0"OD Thin-Wall Tube Sampler =Screened casing clay with sand or gravel (including Shelby tube) .=with Hfilter p •m � � 9 Y •:with filter pack Grab Sample End cap Organic clay or silt of O Portion not recovered LL off medium to high (t) (4) Percentage by dry weight Depth of groundwater plasticity (2) (SPT)Standard Penetration Test (ASTM D-1586) 1 ATD=At time of drilling 2 Peat, muck and other (3) -7 Static water level(date) In General Accordance with o, rn PT highly organic soils Standard Practice for Description (5) Combined USCS symbols used for O and Identification of Soils(ASTM D-2488) fines between 5%and 15% Classifications of soils in this report are based on visual field and/or laboratory observations,which include density/consistency,moisture condition,grain size,and plasticity estimates and should not be construed to imply field or laboratory testing unless presented herein.Visual-manual and/or laboratory classification c methods of ASTM 0-2487 and D-2488 were used as an identification guide for the Unified Soil Classification System. a _ Associated Earth Sciences, Inc. FIGURE vtij ® ® ® ® Exploration Log Key A_1 a -- -- -- Associated Earth Sciences, Inc. Exploration Loci ® ® ® ® Project Number Exploration Number Sheet KE03330A EB-1 1 of 1 Project Name Kennydale Elementary Ground Surface Elevation(ft) Location Renton WA Datum N/A Driller/Equipment Davies Drilling / HSFA Date Start/Finish 8/15/03r 11�Q3 Hammer Weight/Drop 140#/ 30" Hole Diameter(in) c 5 w L N C N — Blows/Foot �- o T `` E aa— o `m CDu) � � m o DESCRIPTION 10 20 30 40 Fill 15 S-1 Damp,yellow-brown, SILTY fine SAND(SM),rounded gravel. 8 A14 Damp,brown,SILTY fine SAND(SM),few fine rounded gravel. 6 5 2 - S-2 Moist,dark brown, SILTY fine to medium SAND(SM),few grounded 2 3 gravel,few organics. 1 ---------------------------------- Till 10 Moist, blue-gray,SILTY SAND,trace rounded gravel(SM),trace orange 7 S-3 oxidation. 27 77/ 1" o/ 15 Moist,blue-gray,SILTY SAND,trace rounded gravel(SM),trace orange 27 S-4 oxidation. 22 72/ 1" O/ " Bottom of exploration boring at 16.5 feet 20 25 30 i 0 35 N IN N N E m n m i Sampler Type(ST): 2"OD Split Spoon Sampler(SPT) F] No Recovery M-Moisture Logged by: MT o ® 3"OD Split Spoon Sampler(D&M) 11 Ring Sample Water Level Q Approved by: co W ® Grab Sample Z Shelby Tube Sample 1 Water Level at time of drilling(ATD) LU Associated Earth Sciences, Inc. Exploration LO 1 ® ® % ® Project Number Exploration Number Sheet KE03330A EB-2 1 of 1 Project Name Kennvdale Elementary Ground Surface Elevation(ft) Location Renton. WA Datum N/A Driller/Equipment Davies Drilling/ HSFA Date Start/Finish 8/15/03 9/15/2003 Hammer Weight/Drop 140#/30" _ Hole Diameter(in) tq UO .O > � y _ Blows/Foot CL co DESCRIPTION 0 3: 10 20 30 40 O Fill 3 S-1 Damp,brown, SILTY SAND,few rounded gravel(SM),mottled,orange 2 A3 oxidation. 1 Moist to wet,brown to dark brown,SILTY SAND(SM),few rounded gravel, mottled. i 5 ------------ Weathered Till ------------ 3 S-2 Wet to saturated,gray,SILTY fine to medium SAND(SM),few rounded i 7 Al gravel,large cobble encountered at 7'. 8 --------------------------------- Till 10 S-3 Wet,gray,SILTY fine to coarse SAND,few fine gravel(SM),orange 15 A 8 oxidation. 33 I I 15 S-4 Moist,gray,SILTY fine to coarse SAND(SM),few fine gravel. as 0/ A L50/f ,I Bottom of exploration boring at 16 feet I 20 25 I 30 I rS 35 N I t") N a a m a Sampler Type(ST'): o m 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: MT 0 3"OD Split Spoon Sampler D&M Ring Sample � Water Level Approved by: ® P P P ( ) 9 P 0 w La ® Grab Sample Z Shelby Tube Sample 1 Water Level at time of drilling(ATD) a Associated Earth Sciences, Inc. Exploration Log ® ® Ni U Project Number Exploration Number Sheet 1110 i KE03330A EB-3 1 of 1 ' Project Name Kennydale Elementary Ground Surface Elevation(ft) Location Renton WA Datum N/A Driller/Equipment Davies Drilling / HSFA Date Start/Finish $11,9/f13.811 12003 Hammer Weight/Drop 140#/30" Hole Diameter(in) i L 2 a� �, 2 Blows/Foot � o T E 15 >, �E 2 0 CD r rn m m o DESCRIPTION 10 20 30 40 O Fill 2 S 1 Moist to wet brown-gray,fine to medium SAND(SP),orange oxidation, 9 A1 round gravel fragments in tip of sampler. 7 , I --------------------- ------ 5 T Weathered Till S 2 Moist to wet,gray,fine to medium SAND(SP),orange oxidation, mottling. i 5 6 A 7 9 I - 10 ——— -------Till —————————————— 45 j S-3 Wet to moist,blue-gray,fine to coarse SAND,few rounded gravel(SP) o/ 50/ " I 15 S-4 Moist,blue-gray,fine to coarse SAND(SP). 13 Bottom of exploration boring at 16 feet 20 ,I 25 I 30 l 35 N C N I � L d o Sampler Type(ST): o m 2"OD Split Spoon Sampler(SPT) Q No Recovery M-Moisture Logged by: MT o m 3"OD Split Spoon Sampler(D&M) U Ring Sample �Z Water Level() Approved by:co w ® Grab Sample 0 Shelby Tube Sample 1 Water Level at time of drilling(ATD) a Associated Earth Sciences, Inc. Exploration Loci ® ® ® ® Project Number Exploration Number Sheet KE03330A EB-4 1 of 1 Project Name Kennydale Elementa[y Ground Surface Elevation(ft) Location Renton, WA Datum N/A Driller/Equipment Davies Drilling/HSFA Date Start/Finish 8/15/03 $/1519003 Hammer Weight/Drop 140#/30" Hole Diameter(in) c a� v N L-6 O > W °' —Q) � N Blows/Foot cL a� CD c) T in (9 to o r DESCRIPTION U m 10 20 30 40 O Fill 3 S-1 Damp to moist,yellow-light gray,SILTY fine to medium SAND(SM),slight 4 A orange oxidation. 4 --------------------------------- Recessional Outwash 5 Damp to moist,yellow-light gray,SILTY fine to medium SAND(SM). 4 S-2 4 9 5 i ----------------------------------- Till I i - 10 S 3 Moist to wet,brown-gray, SILTY fine to medium SAND(SM). 11 15 40 25 i I 15 S-4 No recove1y. or 501 " Bottom of exploration boring at 15.5 feet 20 25 30 0 35 N t+J N v E a a o Sampler Type(ST): o m 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: MT o m 3"OD Split Spoon Sampler(D&M) Ring Sample S? Water Level() Approved by: Q( w ® Grab Sample Q Shelby Tube Sample-T Water Level at time of drilling(ATD) �> a Associated Earth Sciences, Inc. Exploration LO ® ® ® ® Project Number Exploration Number Sheet KE03330A EB-5 1 of 1 Project Name Kennydale Elementary Ground Surface Elevation(ft) Location Renton, WA Datum N/A Driller/Equipment Davies Drilling /HSFA Date Start/Finish 8/1 i/03,811.r,/2003 Hammer Weight/Drop 140#/30" Hole Diameter(in) _ c a� n � � � O .� > cD En a s E � E o Blows/Foot T DESCRIPTION L) 310 10 20 30 40 0 Weathered Till 6 S-1 Damp,brown-gray,SILTY SAND(SM),few fine gravel. 14 A33 19 ——————--—————————— ————————— Till 5 S-2 Damp to moist,gray,SILTY SAND,few fine gravel(SM). 0/ 50/ " 10 S 3 Damp to moist,gray,SILTY SAND,few fine gravel(SM). 10 19 54 35 I 15 S-4 Damp to moist,gray,SILTY SAND,few fine gravel(SM). 16" 50/ " Bottom of exploration boring at 16 feet 20 25 I 30 i o 35 N N E a E m a v n o Sampler Type(ST): o 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: MT m ® T'OD Split Spoon Sampler(D&M) U Ring Sample Q Water Level() Approved by: © Grab Sample Z Shelby Tube Sample 1 Water Level at time of drilling(ATD) Associated Earth Sciences, Inc. Exploration Log ® ® ® ® Sheet Project Number Exploration Number KE03330A EB-6 1 of 1 Project Name Kennydale Elementary Ground Surface Elevation(ft) Location Renton, WA Datum N/A Driller/Equipment Davies Drilling / HSFA Date Start/Finish 9/15/03,8/1512003 Hammer Weight/Drop 140#/30" Hole Diameter(in) c a> U U O > V) °' L —a) Blows/Foot — �� T m DESCRIPTION 10 20 30 40 ° Weathered Till S-1 Damp,yellow-brown,SILTY SAND,trace organic,trace rounded gravel. 6 �1 s --------------------------------- Till 5 S 2 Damp to moist,brown to light brown,SILTY fine to medium SAND(SP). 14 13 3 22 10 30 JS-3 Moist,gray,fine to medium SAND(SP),trace silt,trace rounded gravel. 014, A k50/," I 15 S-4 Moist.blue-gray,SILTY SAND(SM),trace rounded gravel. 24 0/1 L50/,'" Bottom of exploration boring at 16 feet 20 25 30 35 N N E E a t! C7 o Sampler Type(ST): 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: MT o i 3"OD Split Spoon Sampler(D&M) U Ring Sample SZ Water Level() Approved by: a p 0 Shelby Tube Sample 1 Water Level at time of drilling(ATD) ® Grab Sample Associated Earth Sciences, Inc. Exploration Loci ® ® ® ® Project Number Exploration Number Sheet KE03330A EB-7 1 of 1 Project Name Kennydale Elementary Ground Surface Elevation(ft) Location Renton, WA Datum _N/A Driller/Equipment Davies Drilling/ HSFA Date Start/Finish 8/19/03r8115/2003 Hammer Weight/Drop 140#/30" Hole Diameter(in) w S C wU— 0 CU) a Blows/FootQE 0 > 0o0 'ET n m r DESCRIPTION 10 20 30 40 ° 1/4-min usan--la rr ravel---____ __—___ 5 S-1 Weathered Till 5 10 Moist to wet,yellow-brown to gray, SILTY fine to coarse SAND(SM),few 5 fine gravel. i 5 Wet,yellow-brown to gray,SILTY fine to coarse SAND(SM),few fine 4 S-2 gravel. L 5 A18 13 ---------------------- Till 10 Saturated,gray,medium to coarse SAND(SP)to SILTY SAND,few fine 20 S-3 gravel(SM),orange oxidation. 19 50 31 ,I 15 Saturated,gray, medium to coarse SAND(SP)to SILTY SAND,few fine 19 S-4 gravel(SM),orange oxidation. 25 75/ 1" Bottom of exploration boring at 16.5 feet 20 �! 25 I 30 I 0 35 N c N W 1] N O_ U/ a o Sampler Type(ST): 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: MT I ^� m ® 3"OD Split Spoon Sampler(D&M) U Ring Sample SZ Water Level() Approved by: f l w I © Grab Sample 0 Shelby Tube Sample-T Water Level at time of drilling(ATD) a t Associated Earth Sciences, Inc. Exploration LO ® ® J ® Project Number Exploration Number Sheet KE03330A EB-8 1 of 1 Project Name Kennydale Elementary Ground Surface Elevation(ft) Location Renton WA N/A Datum Driller/Equipment Davies Drilling/HSFA Date Start/Finish 81115103.911512003 /512003 Hammer Weight/Drop 140#/30" Hole Diameter(in) — t a Qao (D Blows/Foot n S E 2 ; �E .9 m T � Corn U ca lm O DESCRIPTION 10 20 30 40 Fill 15 S-1 1/2"minus,rounded gravel(3"thick). 19 31 Moist,red-brown,SILTY fine SAND(SM). 12 Till 5 Moist to saturated,gray,SILTY fine to medium SAND(SM)to fine to 6 S-2 medium SAND with trace of silt,few rounded gravel(SP). i 15 40 25 i 10 Saturated,gray,SILTY fine to medium SAND(SM)to fine to medium 10 S-3 SAND with trace of silt,few rounded gravel(SP). 15 A4 30 15 S-4 Moist,gray,SILTY fine to medium SAND(SM)to fine to medium SAND 06, 50/5" with trace 'It few rounded gravel(SP). Bottom of exploration boring at 16 feet 20 25 30 0 35 N C] N U] 0l a o Sampler Type(ST): o m 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: MT m m 3"OD Split Spoon Sampler(D&M) 11 Ring Sample Water Level() Approved by: AYA� W ® Grab Sample Z Shelby Tube Sample 1 Water Level at time of drilling(ATD) Q Associated Earth Sciences, Inc. Exploration Log ® ® ® ® Project Number Exploration Number Sheet KE03330A EB-9 1 of 1 Project Name Kennydale Elementary Ground Surface Elevation (ft) Location Renton, WA Datum N/A Driller/Equipment Davies Drilling / HSFA Date Start/Finish L3/1 S/03 1911512003 Hammer Weight/Drop 140#/30" Hole Diameter(in) p o > y a Q E �, � N Blows/Foot a S E > a �5 o v @ c� E L T coDESCRIPTION " 10 20 30 40 ° Recessional Outwash 5 �j S-1 Damp, light brown,SILTY fine SAND(SM), trace root hairs a A 18 10 5 S 2 Damp,yellow-brown,SILTY fine to medium SAND(SM). 4 . 6 12 6 10 Damp to wet, light yellow-brown,SILTY fine SAND(SM),orange oxidation. g S-3 T 5 �12 7 ------------ Till 15 Moist to wet,blue-gray,SILTY fine to coarse SAND(SM). 14 I TS-4 27 56 27 20 S-5 Moist,blue-gray,SILTY fine to coarse SAND(SM). 26 5)15.5 50/ .5" Bottom of exploration boring at 21 feet 25 30 i I 35 N � (V E D E n m a o Sampler Type(ST): m 2"OD Split Spoon Sampler(SPT) ❑ No Recovery M-Moisture Logged by: MT m ® 3"OD Split Spoon Sampler(D&M) U Ring Sample Q Water Level() Approved by: M w ® Grab Sample Z Shelby Tube Sample-T Water Level at time of drilling(ATD) a 'Associated Earth Sciences, Inc. Exploration Lo ® ® ® ® Project Number Exploration Numberg7 Sheet KE03330A EB-10 1 of 1 Project Name Kenny ale Elementary Ground Surface Elevation(ft) Location Renton WA Datum N/A Driller/Equipment Davies Drilling/ HSFA Date Start/Finish -i/1 5/0 3 8/1 512003 Hammer Weight/Drop _140#/30" Hole Diameter(in) N U F�E u) L O CO N Q S E T 3 Blows/Foot a Q N T <n CD cn o a`)DESCRIPTION m 10 20 30 ao ° ■ S-1 Fill Damp,light brown,SILTY fine SAND(SM). 10 ♦2 15 Recessional Outwash —— 5T Moist,yellow-brown,SILTY fine to medium SAND(SM),orange oxidation, 4 S-2 mottling. 7 14 7 10 Saturated,olive-brown,fine SANDY SILT(ML)to SILTY fine to medium S-3 SAND(SM). i 5 A111 6 ----------- TTII 15 S-4 Wet, blue-gray,SILTY fine to coarse SAND,few rounded gravel(SM). 13 30 L69 39 20 Moist, blue-gray,SILTY fine to coarse SAND,few rounded gravel(SM). 14 S-5 31 75 44 Bottom of exploration boring at 21.5 feet 25 i 30 I I 35 N t`) N I N E N a U) a o Sampler Type(ST): 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: MT m 3"OD Split Spoon Sampler(D&M) U Ring Sample Q Water Level() Approved by: w ® Grab Sample 0 Shelby Tube Sample_L Water Level at time of drilling(ATD) Associated Earth Sciences, Inc. Exploration Log ® ® ® ® Project Number Exploration Number Sheet KE03330A EB-11 1 of 1 Project Name Kennydale Elementary Ground Surface Elevation(ft) Location Renton, WA Datum N/A Driller/Equipment Davies Drilling/HSFA Date Start/Finish 8115103,$/1512003 Hammer Weight/Drop 140#/30" Hole Diameter(in) o > " in t a n� a) Blows/Foot 0 o T to 0� �E w L � � m DESCRIPTION 10 20 30 40 O Recessional Outwash 3 - S-1 Damp,yellow-brown,fine SANDY SILT(ML)to SILTY fine SAND(SM). a 3 ■ 5 Moist,yellow-gray,SILTY fine SAND/SANDY SILT(SM-ML). 6 TS-2 9 Al 7 --------------------------------- Till 10 Saturated,yellow-gray,SILTY fine to medium SAND,few fine gravel(SM), 6 S-3 orange oxidation. i 12 31 19 15 Moist,blue-gray,SILTY fine to medium SAND(SM),trace fine gravel, 19 S 4 slight orange oxidation. 33 A75 42 Bottom of exploration boring at 16.5 feet - 20 25 30 ■ 35 N N N E N N a o Sampler Type(ST): m 2"OD Split Spoon Sampler(SPT) ❑ No Recovery M-Moisture Logged by: MT o [D 3"OD Split Spoon Sampler(D&M) 1] Ring Sample SZ Water Level Q Approved by: W ® Grab Sample Z Shelby Tube Sample 1 Water Level at time of drilling(ATD) a Associated Earth Sciences, Inc. Exploration LO ® ® ® ® Project Number Exploration Number Sheet KE03330A EB-12 1 of 1 Project Name Kennydale Elementary -- Ground Surface Elevation (ft) Location Renton WA Datum N/A Driller/Equipment Davies Drilling / HSFA Date Start/Finish R115103 8/15/2(m Hammer Weight/Drop 140#/30" Hole Diameter(in) C: _�) i2 U 5 N a Qa ,z J N Blows/Foot o T in CDu �E C o L U CU m O DESCRIPTION 10 20 30 40 Topsoil 5 S-1 Yellow brown SILTY_fine SAND 1SM)root hairs. __________1 13 �18 Recessional Outwash 5 Moist,brown to gray,SILTY fine to coarse SAND,few gravel(SM),orange oxidation,mottling. ■ 5 Moist,brown to gray,SILTY fine to coarse SAND,few gravel(SM),orange 3 S-2 oxidation,mottling. 4 3 i 10 Saturated,brown to gray,SILTY fine to coarse SAND,few gravel(SM), 4 S-3 orange oxidation,mottling. -T 5 Al 10 I Till 15 Wet,gray,SILTY fine SAND(SM),few fine gravel. 31 TS-4 O/E 50/ ' 'i 20 S_5 Moist,blue-gray.SILTY fine to coarse SAND(SM),few fine gravel. 30 o 50/ " Bottom of exploration boring at 21.5 feet 25 30 I ■ 35 a N cl Ul E E m m I � a o Sampler Type(ST): o 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: MT m ® 3"OD Split Spoon Sampler(D& M) U Ring Sample Water Level() Approved by: w ® Grab Sample Z Shelby Tube Sample 1 Water Level at time of drilling(ATD) a Appendix D APPENDIX D Operations and Maintenance Manual COUGHLIN PORTER LUNDEEN Kennydale Elementary School 25 Renton,Washington KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 1 -DETENTION PONDS Maintenance Defect Conditions When Maintenance Results Expected When Component Is Needed Maintenance Is Performed General Trash&Debris Any trash and debris which exceed 1 cubic foot Trash and debris cleared from site. per 1,000 square feet(this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Poisonous Vegetation Any poisonous or nuisance vegetation which No danger of poisonous vegetation may constitute a hazard to County personnel or where County personnel or the the public. public might normally be. (Coordination with Seattle-King County Health Department) Pollution Oil,gasoline,or other contaminants of one No contaminants present other than gallon or more or any amount found that could: a surface film. (Coordination with 1)cause damage to plant,animal,or marine life; Seattle/King County Health 2)constitute a fire hazard;or 3)be flushed Department) downstream during rain storms. Unmowed Grass/ If facility is located in private residential area, When mowing is needed, Ground Cover mowing is needed when grass exceeds 18 grass/ground cover should be inches in height. In other areas,the general mowed to 2 inches in height. policy is to make the pond site match adjacent Mowing of selected higher use ground cover and terrain as long as there is no areas rather than the entire slope interference with the function of the facility. may be acceptable for some situations. Rodent Holes Any evidence of rodent holes if facility is acting Rodents destroyed and dam or as a dam or berm,or any evidence of water berm repaired. (Coordination with piping through dam or berm via rodent holes. Seattle/King County Health Department) Insects When insects such as wasps and hornets Insects destroyed or removed from interfere with maintenance activities. site. Tree Growth Tree growth does not allow maintenance access Trees do not hinder maintenance or interferes with maintenance activity(i.e.,slope activities. Selectively cultivate trees mowing,silt removal,vactoring,or equipment such as alders for firewood. movements). If trees are not interfering with access,leave trees alone. Side Slopes of Pond Erosion Eroded damage over 2 inches deep where Slopes should be stabilized by cause of damage is still present or where there using appropriate erosion control is potential for continued erosion. measure(s);e.g.,rock reinforcement,planting of grass, compaction. Storage Area Sediment Accumulated sediment that exceeds 10%of the Sediment cleaned out to designed designed pond depth. pond shape and depth;pond reseeded if necessary to control erosion. Pond Dikes Settlements Any part of dike which has settled 4 inches lower Dike should be built back to the than the design elevation. design elevation. Emergency Rock Missing Only one layer of rock exists above native soil in Replace rocks to design standards. Overflow/Spillway area five square feet or larger,or any exposure of native soil at the top of out flow path of spillway. Rip-rap on inside slopes need not be replaced. 1998 Surface Water Design Manual 9/1/98 A-1 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 3 -CLOSED DETENTION SYSTEMS (PIPES/TANKS) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Storage Area Plugged Air Vents One-half of the cross section of a vent is blocked at Vents free of debris and any point with debris and sediment sediment Debris and Accumulated sediment depth exceeds 10%of the All sediment and debris Sediment diameter of the storage area for length of storage removed from storage area. vault or any point depth exceeds 15%of diameter. Example:72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than%length of tank. Joints Between Any crack allowing material to be transported into All joint between tank/pipe Tank/Pipe Section facility sections are sealed Tank Pipe Bent Any part of tank/pipe is bent out of shape more than Tank/pipe repaired or replaced Out of Shape 10%of it's design shape to design. Manhole Cover Not in Place Cover is missing or only partially in place.Any open Manhole is closed. manhole requires maintenance. Locking Mechanism cannot be opened by one maintenance Mechanism opens with proper Mechanism Not person with proper tools.Bolts into frame have less tools. Working than'%inch of thread(may not apply to self-locking lids.) Cover Difficult to One maintenance person cannot remove lid after Cover can be removed and Remove applying 80lbs of lift. Intent is to keep cover from reinstalled by one maintenance sealing off access to maintenance. person. Ladder Rungs King County Safety Office and/or maintenance person Ladder meets design standards Unsafe judges that ladder is unsafe due to missing rungs, allows maintenance person safe misalignment,rust,or cracks. access. Catch Basins See"Catch Basins"Standards No.5 See"Catch Basins"Standards No.5 r 9/1/98 1998 Surface Water Design Manual A-2 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO.4-CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Defect Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed General Trash and Debris Distance between debris build-up and bottom of All trash and debris removed. (Includes Sediment) orifice plate is less than 1-1/2 feet. Structural Damage Structure is not securely attached to manhole wall Structure securely attached to and outlet pipe structure should support at least wall and outlet pipe. 1,000 Ibs of up or down pressure. Structure is not in upright position(allow up to Structure in correct position. 10%from plumb). Connections to outlet pipe are not watertight and Connections to outlet pipe are show signs of rust. water tight;structure repaired or replaced and works as designed. Any holes--other than designed holes--in the Structure has no holes other structure. than designed holes. Cleanout Gate Damaged or Missing Cleanout gate is not watertight or is missing. Gate is watertight and works as designed. Gate cannot be moved up and down by one Gate moves up and down easily maintenance person. and is watertight. Chain leading to gate is missing or damaged. Chain is in place and works as designed.. Gate is rusted over 50%of its surface area. Gate is repaired or replaced to meet design standards.. Orifice Plate Damaged or Missing Control device is not working properly due to Plate is in place and works as missing,out of place,or bent orifice plate. designed. Obstructions Any trash,debris,sediment,or vegetation Plate is free of all obstructions blocking the plate. and works as designed. Overflow Pipe Obstructions Any trash or debris blocking(or having the Pipe is free of all obstructions potential of blocking)the overflow pipe. and works as designed. Manhole See"Closed Detention Systems"Standards No.3 See"Closed Detention Systems' Standards No.3 Catch Basin See"Catch Basins"Standards No.5 See'Catch Basins"Standards No.5 1998 Surface Water Design Manual 9/1/98 A-3 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 5 -CATCH BASINS Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed General Trash &Debris Trash or debris of more than 1/2 cubic foot which is No Trash or debris located (Includes Sediment) located immediately in front of the catch basin immediately in front of catch opening or is blocking capacity of the basin by basin opening. more than 10% Trash or debris(in the basin)that exceeds 1/3 the No trash or debris in the catch depth from the bottom of basin to invert the lowest basin. pipe into or out of the basin. Trash or debris in any inlet or outlet pipe blocking Inlet and outlet pipes free of more than 1/3 of its height. trash or debris. Dead animals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within the catch basin. gases(e.g.,methane). Deposits of garbage exceeding 1 cubic foot in No condition present which volume would attract or support the breeding of insects or rodents. Structure Damage to Corner of frame extends more than 3/4 inch past Frame is even with curb. Frame and/or Top Slab curb face into the street(If applicable). Top slab has holes larger than 2 square inches or Top slab is free of holes and cracks wider than 1/4 inch(intent is to make sure cracks. all material is running into basin). Frame not sitting flush on top slab, i.e.,separation Frame is sitting flush on top of more than 3/4 inch of the frame from the top slab. slab. Cracks in Basin Walls/ Cracks wider than 1/2 inch and longer than 3 feet, Basin replaced or repaired to Bottom any evidence of soil particles entering catch basin design standards. through cracks,or maintenance person judges that structure is unsound. Cracks wider than 1/2 inch and longer than 1 foot No cracks more than 1/4 inch at the joint of any inlet/outlet pipe or any evidence wide at the joint of inlet/outlet of soil particles entering catch basin through pipe. cracks. Sediment/ Basin has settled more than 1 inch or has rotated Basin replaced or repaired to Misalignment more than 2 inches out of alignment. design standards. 9/1/98 1998 Surface Water Design Manual A-4 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 5 -CATCH BASINS (CONTINUED) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed Fire Hazard Presence of chemicals such as natural gas,oil and No flammable chemicals gasoline. present. Vegetation Vegetation growing across and blocking more than No vegetation blocking opening 10%of the basin opening. to basin. Vegetation growing in inlet/outlet pipe joints that is No vegetation or root growth more than six inches tall and less than six inches present. apart. Pollution Nonflammable chemicals of more than 1/2 cubic foot No pollution present other than per three feet of basin length. surface film. Catch Basin Cover Cover Not in Place Cover is missing or only partially in place.Any open Catch basin cover is closed catch basin requires maintenance. Locking Mechanism Mechanism cannot be opened by on maintenance Mechanism opens with proper Not Working person with proper tools.Bolts into frame have less tools. than 1/2 inch of thread. Cover Difficult to One maintenance person cannot remove lid after Cover can be removed by one Remove applying 80 lbs.of lift;intent is keep cover from maintenance person. sealing off access to maintenance. Ladder Ladder Rungs Ladder is unsafe due to missing rungs,misalignment, Ladder meets design standards Unsafe rust,cracks,or sharp edges. and allows maintenance person safe access. Metal Grates Grate with opening wider than 718 inch. Grate opening meets design (If Applicable) standards. Trash and Debris Trash and debris that is blocking more than 20%of Grate free of trash and debris. grate surface. Damaged or Grate missing or broken member(s)of the grate. Grate is in place and meets Missing. design standards. NO. 6 DEBRIS BARRIERS (E.G.,TRASH RACKS) Maintenance Defect Condition When Maintenance is Needed Results Expected When Components Maintenance is Performed. General Trash and Debris Trash or debris that is plugging more than 20%of Barrier clear to receive capacity the openings in the barrier. flow. Metal Damaged/Missing Bars are bent out of shape more than 3 inches. Bars in place with no bends more Bars. than 3/4 inch. Bars are missing or entire barrier missing. Bars in place according to design. Bars are loose and rust is causing 50%deterioration Repair or replace barrier to to any part of barrier. design standards. 1998 Surface Water Design Manual 9/1/98 A-5 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 7 -ENERGY DISSIPATERS Maintenance Defect Conditions When Maintenance is Needed Results Expected When Components Maintenance is Performed. External: Rock Pad Missing or Moved Only one layer of rock exists above native soil in Replace rocks to design Rock area five square feet or larger,or any exposure of standards. native soil. Dispersion Trench Pipe Plugged with Accumulated sediment that exceeds 20%of the Pipe cleaned/flushed so that it Sediment design depth. matches design. ' Not Discharging Visual evidence of water discharging at Trench must be redesigned or Water Properly concentrated points along trench(normal condition rebuilt to standards. is a"sheet flout'of water along trench). Intent is to prevent erosion damage. Perforations Over 1/2 of perforations in pipe are plugged with Clean or replace perforated pipe. Plugged. debris and sediment. Water Flows Out Maintenance person observes water flowing out Facility must be rebuilt or Top of"Distributor" during any storm less than the design storm or its redesigned to standards. Catch Basin. causing or appears likely to cause damage. Receiving Area Water in receiving area is causing or has potential No danger of landslides. Over-Saturated of causing landslide problems. Internal: Manhole/Chamber Worn or Damaged Structure dissipating flow deteriorates to 1/2 or Replace structure to design Post. Baffles,Side original size or any concentrated worn spot standards. of Chamber exceeding one square foot which would make structure unsound. Other Defects See"Catch Basins"Standard No.5 See"Catch Basins"Standard No. 5 9/l/98 1998 Surface Water Design Manual A-6 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 8 -FENCING Maintenance Defect Conditions When Maintenance is Needed Results Expected When Components Maintenance is Performed General Missing or Broken Any defect in the fence that permits easy entry Parts in place to provide adequate Parts to a facility. security. Erosion Erosion more than 4 inches high and 12-18 No opening under the fence that inches wide permitting an opening under a exceeds 4 inches in height. fence. Wire Fences Damaged Parts Post out of plumb more than 6 inches. Post plumb to within 1-1/2 inches. Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch. Any part of fence(including post,top rails,and Fence is aligned and meets design fabric)more than 1 foot out of design alignment. standards. Missing or loose tension wire. Tension wire in place and holding fabric. Missing or loose barbed wire that is sagging Barbed wire in place with less than more than 2-1/2 inches between posts. 3/4 inch sag between post. Extension arm missing,broken,or bent out of Extension arm in place with no shape more than 1 1/2 inches. bends larger than 3/4 inch. Deteriorated Paint or Part or parts that have a rusting or scaling Structurally adequate posts or Protective Coating condition that has affected structural adequacy. parts with a uniform protective coating. Openings in Fabric Openings in fabric are such that an 8-inch- No openings in fabric. diameter ball could fit through. NO. 9 -GATES Maintenance Defect Conditions When Maintenance is Needed Results Expected When ■ Component Maintenance is Performed General Damaged or Missing Missing gate or locking devices. Gates and Locking devices in Members place. Broken or missing hinges such that gate cannot Hinges intact and tubed.Gate is be easily opened and closed by a maintenance working freely. person. Gate is out of plumb more than 6 inches and Gate is aligned and vertical. more than 1 foot out of design alignment. Missing stretcher bar,stretcher bands,and ties. Stretcher bar,bands and ties in place. Openings in Fabric See"Fencing"Standard No.8 See"Fencing"Standard No.8 1998 Surface Water Design Manual 9/1/98 A-7 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 10 -CONVEYANCE SYSTEMS (PIPES &DITCHES) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Pipes Sediment&Debris Accumulated sediment that exceeds 20%of the Pipe cleaned of all sediment diameter of the pipe. and debris. Vegetation Vegetation that reduces free movement of water All vegetation removed so water through pipes. flows freely through pipes. Damaged Protective coating is damaged;rust is causing Pipe repaired or replaced. more than 50%deterioration to any part of pipe. Any dent that decreases the cross section area of Pipe repaired or replaced. pipe by more than 20%. Open Ditches Trash&Debris Trash and debris exceeds 1 cubic foot per 1,000 Trash and debris cleared from square feet of ditch and slopes. ditches. Sediment Accumulated sediment that exceeds 20%of the Ditch cleaned/flushed of all design depth. sediment and debris so that it matches design. Vegetation Vegetation that reduces free movement of water Water flows freely through through ditches. ditches. Erosion Damage to See"Ponds"Standard No. 1 See"Ponds"Standard No. 1 Slopes Rock Lining Out of Maintenance person can see native soil beneath Replace rocks to design Place or Missing(If the rock lining. standards. Applicable). Catch Basins See"Catch Basins:Standard No.5 See"Catch Basins"Standard No.5 Debris Barriers See"Debris Barriers"Standard No.6 See"Debris Barriers"Standard (e.g.,Trash Rack) No.6 NO. 11 -GROUNDS (LANDSCAPING) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed General Weeds Weeds growing in more than 20%of the landscaped Weeds present in less than 5% (Nonpoisonous) area(trees and shrubs only). of the landscaped area. Safety Hazard Any presence of poison ivy or other poisonous No poisonous vegetation vegetation. present in landscaped area. Trash or Litter Paper,cans,bottles,totaling more than 1 cubic foot Area clear of litter. within a landscaped area(trees and shrubs only)of 1,000 square feet. Trees and Shrubs Damaged Limbs or parts of trees or shrubs that are split or Trees and shrubs with less than broken which affect more than 25%of the total 5%of total foliage with split or foliage of the tree or shrub. broken limbs. Trees or shrubs that have been blown down or Tree or shrub in place free of knocked over. injury. Trees or shrubs which are not adequately supported Tree or shrub in place and or are leaning over,causing exposure of the roots. adequately supported;remove any dead or diseased trees. 9/1/98 1998 Surface Water Design Manual A-8 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 13-WATER QUALITY FACILITIES A.)Typical Biofiltration Swale Maintenance Defect or Problem Condition When Maintenance is Recommended Maintenance to Correct Component Needed Problem Biofiltration swale Sediment Accumulation Sediment depth exceeds 2-inches Remove sediment deposits on grass on Grass treatment area of the bio-Swale. When finished,swale should be level from side to side and drain freely toward outlet. There should be no areas of standing water once inflow has ceased. Standing water When water stands in the swale Any of the following may apply: remove between storms and does not drain sediment or trash blockages, improve grade freely. from head to foot of swale, remove clogged check dams, add underdrains or convert to a wet biofiltration swale. Flow spreader Flow spreader uneven or clogged so Level the spreader and clean so that flows that flows are not uniformly distributed are spread evenly over entire wale width. through entire swale width. Constant baseflow When small quantities of water Add a low-flow pea-gravel drain the length continually flow through the swale,even of the swale(see p. 6-42)or by-pass the when it has been dry for weeks,and an baseflow around the swale. eroded,muddy channel has formed in the swale bottom. Poor vegetation When grass is sparce or bare or eroded Determine why grass growth is poor and coverage patches occur in more than 10%of the correct that condition. Re-plant with plugs swale bottom. of grass from the upper slope:plant in the swale bottom at 8-inch intervals. Or reseed into loosened,fertile soil. Vegetation When the grass becomes excessively Mow vegetation or remove nuisance tall(greater than 10-inches);when vegetation so that flow not impeded.Grass nuisance weeds and other vegetation should be mowed to a height of 3 to 4 starts to take over. inches. Remove grass clippings. Excessive shading Grass growth is poor because sunlight If possible,trim back over-hanging limbs, does not reach swale. remove brushy vegetation on adjacent slopes. Inlet Outlet Inlet/outlet areas clogged with Remove material so that there is no sediment and/or debris. clogging or blockage in the inlet and outlet area. Trash and Debris Trash and debris accumulated in the Remove trash and debris from bioswale. Accumulation bio-swale. Erosion/Scouring Eroded or scoured swale bottom due For ruts or bare areas less than 12 inches to flow channelization,or higher flows. wide,repair the damaged area by filling with crushed gravel. The grass will creep in over the rock in time. If bare areas are large,generally greater than 12 inches wide,the swale should be re-graded and re- seeded.For smaller bare areas,overseed when bare spots are evident,or take plugs of grass from the upper slope and plant in the swale bottom at 8-inch intervals. 1998 Surface Water Design Manual 9/1/98 A-9 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 13-WATER QUALITY FACILITIES (CONTINUED) D.)Wetponds Maintenance Defect or Problem Condition When Maintenance is Recommended Maintenance to Correct Component Needed Problem Wetpond Water level First cell empty,doesn't hold water. Line the first cell to maintain at least 4 feet of water. Although the second cell may drain,the first cell must remain full to control turbulence of the incoming flow and reduce sediment resuspension. Vegetation Vegetation such as grass and weeds Vegetation should be mowed to 4 to 5 need to be mowed when it starts to inches in height. Trees and bushes impede aesthetics of pond.Mowing is should be removed where they are generally required when height exceeds interfering with pond maintenance 18-inches. Mowed vegetation should be activities;that is,at the inlet,outlet and removed from areas where it could enter near engineered structures. the pond,either when the pond level rises, or by rainfall runoff. Trash and Debris Accumulation that exceeds 1 CF per Trash and debris removed from pond. 1000-SF of pond area. Inlet/Outlet Pipe Inlet/Outlet pipe clogged with sediment No clogging or blockage in the inlet and and/or debris material. outlet piping. Sediment Sediment accumulations in pond bottom Removal of sediment from pond bottom. Accumulation in Pond that exceeds the depth of sediment zone Bottom plus 6-inches,usually in the first cell. Oil Sheen on Water Prevalent and visible oil sheen. Remove oil from water by use of oil- sorbant pads or by vactor truck. Refer problem to locate source and correct. If chronic low levels of oil persist,plant wetland plants such as Juncus effusus (soft rush)which can uptake small concentrations of oil. Erosion Erosion of the pond's side slopes and/or Slopes should be stabilized by using scouring of the pond bottom,that exceeds proper erosion control measures,and 6-inches,or where continued erosion is repair methods. prevalent. Settlement of Pond Any part of these components that has Dike/berm is repaired to specifications. Dike/Berm settled 4-inches or lower than the design elevation,or inspector determines dike/ berm is unsound. Internal berm Berm dividing cells should be level Build up low areas of berm or lower high areas so that the berm surface is level and water flows evenly over the entire length of the berm from the first cell to the second. Overflow Spillway Rock is missing and soil is exposed at top Replace rocks to specifications. of spillway or outside slope. 9/1/98 1998 Surface Water.Design Manual A-10 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES NO. 13 -WATER QUALITY FACILITIES (CONTINUED) E.)Wetvaults Maintenance Defect or Problem Condition When Maintenance is Needed Recommended Maintenance to Component Correct Problem - Wetvault Trash/Debris Trash and debris accumulated in vault, pipe Remove trash and debris from vault. Accumulation or inlet/outlet,(includes floatables and non- floatables). Sediment Sediment accumulation in vault bottom Remove sediment from vault. Accumulation in Vault exceeds the depth of the sediment zone plus 6-inches. Damaged Pipes Inlet/outlet piping damaged or broken and Pipe repaired and/or replaced. in need of repair. Access Cover Cover cannot be opened or removed, Pipe repaired or replaced to proper Damaged/Not especially by one person. working specifications. Working Ventilation Ventilation area blocked or plugged Remove or clear blocking material from ventilation area. A specified%of the vault surface area must provide ventilation to the vault interior(see p.6- 82 for required%). Vault Structure Vault:Cracks wider than 1/2-inch and any Repair cracks wider than 1/4-inch at the Damaged evidence of soil particles entering the joint of the inlet/outlet pipe.Make repairs structure through the cracks,or so that vault is structurally sound. maintenance/inspection personnel determines that the vault is not structurally sound. Baffles Baffles corroding,cracking,warping and/or Repair or replace baffles to showing signs of failure as determined by specifications. maintenance/inspection staff. Access Ladder Ladder is corroded or deteriorated,not Ladder replaced or repaired to Damage functioning properly,missing rungs,has specifications,and is safe to use as cracks and/or misaligned. Confined space determined by inspection personnel. warning sign missing. Replace sign warning of confined space entry requirements. 1998 Surface Water Design Manual 9/1/98 A-11