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HomeMy WebLinkAboutSWP272117(8) A C S ENGINEERS, INC. ]ATA 0 PROCHASKA, PEt- Pesiclen June 12, 1991 PAUL PROCHASKA. PE Vice Rr,estderit C�Vll- C i TRANSPORTATION Randal Parsons r%L STRUCTURAL City of Renton Dept . of Public Works 200 Mill Ave. South Renton, WA 98055 Dear Mr. Parsons : Enclosed is the Preliminary Hydraulic Report for the HOV improvements to SR 167 from 15th Street S . W. to South Grady Way. for your review and comments . Paul Prochaska and I would like to meet with you, after your review, to discuss personally your comments and receive any valuable information that could and will effect this report . I would like to schedule this meeting for the first part of next week, June 17-19, as your input is vital and has a direct bearing on this project . Sincerely, o n Gahan S Engineers, Inc . W/enclosure cc: File Paul Prochaska, CTS Engineers, Inc. Ali Mansour w/encl . Alpha Engineers P115 5'u:C e 100 lei (2061 4S9 7622 Bellevue,\A//\90OU4 FAX 12061462-1B74 PRELIMINARY - - - NL 12 HYDRAULIC REPORT (Preliminary) SR 167 MP 13 . 73 to MP 26 . 37 15th Street S .W. to South Grady Way TABLE OF CONTENTS 1 . 0 Vicinity Map 2 . 0 Introduction 3 . 0 Design Criteria and Requirements 4 . 0 Existing Drainage 5 . 0 Proposed Improvements 6 . 0 Drainage Basin Plans 7 . 0 Drainage Analysis 8 . 0 Gutter Design (Inlet Spacing) 9 . 0 Sump Design (Sag Inlet Spacing) 10 . 0 Storm Sewer Design 11 . 0 Detention Design 12 . 0 Culvert Design 13 . 0 Drainage Area Maps 14 . 0 Drainage Plans/Profiles 15 . 0 Appendix 16 . 0 References 2 . 0 INTRODUCTION Washington State Department of Transportation (WSDOT) is proposing to widen the northbound and southbound lanes of SR 167 from the 15th Street S .W. undercrossing near Auburn to South Grady Way in Renton, an approximate length of 12 . 5 miles . The Widening will be used for installation of HOV lanes in this transportation corridor. For ease of planning, the proposed stretch of freeway to be widened has been divided into three sections : A. Section 1 starts at 15th Street S .W. in Auburn and ends at the Green River Bridge, approximately between Sta. 493 .+00 and Sta. 772+00 . B. Section 2 continues from the Green River Bridge to the 84th Avenue South overcrossing Sta. 892+50 . C. Section 3 stretches from the 84th Avenue South bridge to South Grady Way. The entire project is located in King County and runs through the city limits of Auburn, Kent and Renton, thus impacting all three cities. I There are two alternatives being considered for the widening. Alternative A proposes to widen the northbound and southbound lanes toward the median, while Alternative B considers widening the freeway to the outside. The impact of each alternative on the drainage is further discussed in Chapters III and IV. 3 . 0 DESIGN CRITERIA Design Storm Frequency - Interstate Structure (Table 1 -4) Catch Basins . . . . . . . . . . . . . . . . . . . . 10-year Storm Sewers - Trucks . . . . . . . . . . . 25-year Laterals . . . . . . . . . 10-year Inlets . . . . . . . . . . . 10-year Channels. . . . . . . . . . . . . . . . . . . . . . . . 50-year Ditches . . . . . . . . . . . . . . . . . . . . . . . . . 10-year Gutters, S1 . . . . . . . . . . . . . . . . . . . . 10-year Depressed Roadways . . . . . . . . . . . . . 50-year Culverts . . . . . . . . . . . . . . . . . . . . . . . 25-year g. J +� (All storms shall have 24-hour duration) Rainfall Intensity Chart 10 Renton-Seattle Soil Classification Soil Survey for King County Area, Washington (SCS ) Rational Method Runoff Coefficients - Off-site Drainage Rolling Terrain - On-site Drainage Flat Terrain Pre-development Condition SR 167 pavement configuration prior to widening. Post-development Condition SR 167 pavement configuration after widening is completed. 4 . 0 EXISTING DRAINAGE In general terms, SR 167 shares the Green River Valley with other important transportation routes in a north-south direction. Examples are the West Valley Road (SR 181 ) , East Valley Road (known also as 84th Avenue South or Auburn Way North through the project) , Chicago Milwaukee St. Paul & Pacific Railroad and Burlington Northern Railroad. In addition to these major routes, there are numerous streets increasing in density near the central core of each of the cities and major transportation links in the east-west direction, such as, SR 18, SR 516, South 212th Street, S .W. 43rd Street and SR 405 . All of these man-made routes are elevated above the actual grade of the valley thus forming obstacles to the natural drainage flow which is already impeded by the flatness of the entire area. The natural grade change for the whole length of the project changes from elevation 64 . 00 at the south end to elevation 14 . 00 at the north end. The main conduit of the surface water in the valley is the Green River which meanders in a south to north direction with SR 167 being generally parallel to it, except for the area where the freeway crosses the river. In Section 1 of the project, SR 167 follows Mill Creek, a tributary to Green River. Further north in Section 2, SR 167 crosses Garrison Creek which does not have a specific outlet. In Section 3, SR 167 forms a "dam" for a wetland along the east side of the freeway within the City of Renton limits . ` The following description of the existing drainage conditions and drainage structures in the individual sections is based on maps provided by Alpha Engineers and field-verified by CTS Engineers, Inc. technical personnel . A. In Section 1 , SR 167 has been constructed with a wide median between the north and south lanes . For the most part, the roadway superelevation carries the storm water to the outside edges with the exception of two curves in which the water is carried to the median from the respective lanes. The median is drained by a series of catch basins located in the middle at intervals often exceeding 900 feet. Each individual catch basin is drained by a 12-inch diameter pipe either to the east or west side of the freeway. The same is true for the ramps of the interchanges . The 10, x 6' double box culvert located at Sta. 504+60 carries water from the east side of the freeway towards the west which eventually flows into Mill Creek. The 8' x 6' box culvert at Sta. 615+50 serves as a conduit for Mill Creek, crossing the freeway from west to east. A 30-inch diameter pipe at Sta. 638+30 carries water from the east to the west side of the freeway and into Mill Creek where 29th Street N.W. abuts the freeway. North of the 30-inch pipe,, a 24 inch pipe fulfills a similar purpose. A 7' x 8' box culvert carries Mill Creek from the east to the west side of the freeway at Sta. 691 +00 . Just before the South 277th Street interchange, a 4' x 4' box culvert carries water from the east to the west side of the freeway and towards Mill Creek (approx. Sta. 707+35) . An 18-inch diameter pipe at Sta. 757+50 serves to carry water ponding between 72nd Avenue South and SR 167 from the east to the west side of the freeway. B. After crossing the Green River at approximately Sta. 772+50, we have entered Section 2 of the project. The drainage of the median and shoulders of the freeway is basically the same as in Section 1 . The next in line of the existing drainage structures is a 24-inch diameter pipe at Sta. 796+65, just before the interchange with SR 516, and an 18- inch diameter pipe at Sta. 810-00, after the interchange. The first pipe carries water from west to east and the second one carries water from east to west of the freeway. Just before SR 167 crosses over the Chicago Milwaukee St. Paul & Pacific Railroad, there is an 18-inch diameter pipe with uncertain direction of flow and, just after the railroad crossing is a 24-inch diameter pipe at Sta. 845+70 with flow from west to east. Shortly after the railroad crossing there is another 18-inch diameter pipe at Sta. 855- 40 with flow from west to east . The last drainage structures in Section 2 are a 54-inch diameter pipe at Sta. 884+65 which carries water from the east side of the freeway over to the west side and a combination of pipes with different sizes at Sta. 891 +65 . C. The first structure in Section 3 of the project is a 42-inch diameter pipe at Sta. 909+50 with an east to west flow. Further north is an 18-inch diameter pipe at Sta. 916+00 which carries water from the east side of the freeway to the ditch between SR 167 and 88th Avenue South on the west side. The ponding in the ditch is relieved by a series of 8-inch diameter pipes at Sta. 921 crossing 88th Avenue South. Considering the number of pipes shown on the plans, this must be a problem area. An 18-inch diameter pipe located at Sta. 928+65, which takes the water from west to east, compounds the aforementioned problem. The next 18-inch diameter pipe at Sta. 935+30 has the same flow direction. At the same station, the plans show a major stream adjacent to the west side of the freeway. We are now approaching the interchange with the South 212th Street undercrossing. Before we come to the bridge itself, there is a 48-inch diameter pipe at Sta. 943410, taking water from the east to the west side of the freeway and into the aforementioned stream. This 48-inch pipe picks up the drainage from the entire east portion of the interchange. Once on the other side of the bridge, we encounter an 18- inch diameter pipe with the flow from east to west at Sta. 951 +00 . Before the South 208th Street undercrossing is a 24-inch diameter pipe at Sta. 960+30 and after the bridge is an 18-inch diameter pipe at Sta. 962+50, both with the flow from east to west. The major stream still follows the west side of the freeway and this may be the answer to the lost outlet for Garrison Creek. It is apparent from the plans that near Sta. 964+00, we are entering the area with an underground water problem. At this station the plans show an 8-inch diameter perforated pipe located at the center line of the median and further north a similar pipe runs along the east shoulder of the freeway. The water collected by the perforated pipes is carried to the west side of- the freeway by a 12-inch or 18- inch diameter pipes located at Sta. 969+00, Sta. 974+60, Sta. 984+50, Sta. 989+50 and Sta. 994+10 . The perforated pipe in the middle of the median ends at Sta. 994+10 and starts again at Sta. 1004+35 . There are 18-inch diameter pipes across the freeway at Sta. 1002+90 and Sta. 1003+15 without a positive direction of flow. The stream for drainage channel that follows the west side of the freeway takes a sharp turn left towards the west at Sta. 1001 +00 . After the beginning of another length of the 8-inch diametbr r perforated pipe in the median at Sta. 1004+35, we enter a �J part of the freeway with numerous drain pipes installed mainly under the northbound lanes . Pipes across the freeway are located in Sta. 1006+00, Sta. 1009+10 and Sta. 1013+80. The perforated drain pipe at the centerline median terminates at Sta. 1012+00 . A 48-inch diameter pipe provides drainage conduits from east to west at Sta. 1014+85 Z � at which point another drainage channel forms along the west side of the freeway heading north. Another series of pipes across the freeway is subsequently located at Sta. 1018+00 ( 12-inch dia. ) , Sta. 1024+50 (24-inch dia. ) , Sta. 1030+00 (24-inch dia. ) and Sta. 1041+85 ( 30-inch dia. ) . As we approach the South 180th Street undercrossing, there are no major drainage structures crossing the freeway except the usual drains from the median. The drainage channel along the west side of the freeways seems to disappear just before the interchange . The interchange is at the limits of the` City of Kent and Renton and is also known as S .W. 43rd Street on the Renton side . The traffic barrier in the median starts right after the bridge at Sta. 1056+00 with the northbound edge of the pavement extending under the barrier to support it . Coming out of the interchange, the \I ditch formed along the east side is taken across the freeway to the west side by a 24-inch diameter pipe at Sta. 1071 +10 . /Along the east side of SR 167, we have now come to Panther Creek Wetlands . A series of pipes provides relief for the `a wetlands to drain to the west side of the freeway. These pipes are located at Sta. 1075+80 ( 30-inch dia. ) , Sta. 1081 +80 ( 48-inch dia. ) , Sta. 1083+90 ( 36-inch dia. ) , Sta. J \ 1086+20 ( 30-inch dia. ) , Sta. 1091 +70 ( 48-inch dia. ) Sta 1101 +80 ( 48-inch dia. ) , Sta 1106+90 (30-inch dia. ) and Sta. 1115+00 ( 30-inch dia. ) . We are now approaching the interchange with SR 405 which has a number of drainage structures and as indicated on the plans available to us, we have passed over a station equation at Sta. 1128+00 Sta. EE975+00 . We are directly concerned with the 3 ' x 4' culvert transferring the flow from east to west at Sta. EE989+30 . This culvert carries water for about 70% of the entire interchange. An 18-inch diameter pipe at Sta. EE1005+40 is a part of the interchange system with the flow from west to east and is the last drainage structure on this project. There will be future developments along SR 167 which will impact the drainage of the area. In Section 1 , the City of Auburn plans a new development east of SR 167 between Main Street West, 15th Street N.W. and the railroad tracks, and another development east of SR 167 between South 285th Street and South 277th Street which will include partial relocation of Mill Creek. The City of Kent Public Works Department has two projects planned within Section 2 . One project considers improvements of the aquifer well and installation of an industrial wash sewer pipe in the vicinity of the interchange with SR 516 . The other project addresses discharge of drainage under the Green River, west of the SR 516 interchange. In Section 3, the City of Renton has several projects in the i planning stages. The city is proceeding with P-9 Channel construction to improve Panther Creek Wetlands and will request all new and existing culverts crossing SR 1__67 to be tied into P-9; channel and that freeway runoff into the wetland be prevented. The city will also request addressing of the flooding problem near Nendels Motel which will be made worse by SR 167 widening. There will also be a future sewer and water line crossing SR 167 between SR 405 and S.W. 43rd Street. Our site inspection revealed that some drainage structures shown on the plans were not constructed at all or where submerged below the water and therefore could not be identified. Approximately half a dozen structures were built within a 100 foot range from locations shown on the plans . About 40 catch basins shown on the plans were not installed, probably because they were not needed under the specific conditions . The main observation made was that the majority of the drainage structures are plugged or reduced in capacity by sediments and debris . we recommend that the structures be cleaned, including those requiring no work, prior to construction of this project and then a program be made for regular maintenance of the drainage facilities . 5 . 0 PROPOSED IMPROVEMENTS The project proposes to widen the northbound and southbound lanes towards the median. Although at numerous locations main roadways and ramps are widened on the outside. Figures A, B, C, and D in the Appendix show conditions of the widening at different intervals of SR 167 . These figures show prevailing conditions within each section and not the specific conditions at each curve and in transitions . Due to the complexity of this project it is necessary to describe proposed improvements for each section separately. 5 . 1 Section 1 There will be two conditions created by the widening in Section 1 of the 'project. The first condition is shown in Figure A indicating that even after widening of the northbound and southbound lanes there will be ample median left in-between. Therefore the existing drain pipes and catch basins located in the median need not be modified except their cleaning. Since for most part of this section the freeway runs straight the standard superelevation slopes the pavement to the outside edge. Therefore the attractive grass area in the median cannot be used for treatment of the runoff. The second condition in Section 1 occurs where the existing median narrows down and will cease to exist after northbound and southbound lanes are widened. This will not change anything or the fact that most of the runoff is directed by the superelevation towards the shoulders . The embankment of the freeway in Section 1 is rather low with the roadway being elevated four to six feet above the adjacent land with exception of the approach to Green River Bridge. The conditions between the toe of the embankment and WSDOT right-of- way vary from flat to small ponds with standing water to ditch profiles to shallow open channels with various velocity of the water. Outside of the area immediately next to shoulder where growth of vegetation is controlled by WSDOT there is abundance of grass providing biofiltration of the runoff. In most places it is impossible to separate ma hes and ponds on adjacent land from those located within the right-of-way. In order to separate highway runoff from off-site runoff it is proposed to build an obstacle to prevent the highway runoff spilling over the right-of-way line. The form of the obstacle would depend on available space between the toe of the embankment and the right-of-way line. In areas of ample space the obstacle would be a form of an impermeable earth berm forming the outer edge of a biofiltration swale . As the available space narrows this earth berm would change into a ditch with the outerside lined with rip-rap which in turn might change into a concrete wall. Ultimately because of lack of space we maybe left with two alternatives; leave the status quo or tie highway runoff into a closed pipe system. Streams The widening of SR 167 in Section 1 would affect Mill Creek. At this point it would be practical to look at the culverts used by Mill Creek for crossing the freeway and evaluate their capacity. Flood Plain Ultimately this project will affect the Green River Flood Plain. Channel Changes Numerous channels along the freeway will be improved. Culverts Existing culverts under the freeway will be evaluated and added to if required. Ditches Ditches will be improved in the same manner as open channels . Enclosed Drainage No additional enclosed drainage is anticipated for Section -1 . The existing piping will be evaluated for its capacity. Gutter Design No gutter construction is planned for Section 1 . Retention Ponds No retention ponds are considered at this time. Existing Utilities This project does not interfere with any existing or planned utilities . 5 . 2 SECTION 2 In Section 2 the freeway crosses over numerous streets in City of Kent and two sets of multiple railroad tracks and therefore runs off a high embankment . Yet on each side of the freeway are open channels with standing or very slowly moving water. In most instances the on-site ( freeway) runoff is separated from the off- site drainage system. About half the length of the open channels is silted and overgrown with brush. Cleaning them and seeding will greatly improve their biofiltration capacity. Streams In Section 2 there are no local streams to be affected. Flood Plain This project does affect Green River Flood Plain. Channel Changes Maintenance-type improvements will occur at the existing open channels . Culverts Existing culverts under the freeway will be evaluated and added to as required. Ditches No work is anticipated. Enclosed Drainage The existing piping will be evaluated for its capacity. Gutter Design No gutter construction is planned. Existing Utilities This project does not interfere with any existing or planned utilities . 5 . 3 SECTION 3 As SR 167 crosses over 84th Avenue South it becomes again a freeway with low embankment for most of its length. From this point up to South 180th Street the freeway drainage conditions are much alike in Section 1 except the ditches and channels along the embankment are better defined and off-site and on-site runoff are separated. There is one stream in this area, called Garrison Creek for now until its name can be classified with the City of Kent, which is going to be affected by this project. This stream crosses the freeway only once but there is at least one strong tributary to it. Between South 180th Street and SR 405 the freeway serves as a dam for Panther Creek Wetlands . The situation and proposed solutions for this area are described in an engineering report by R. W. Beck & Assoc . called P-9 Channel Design. For our purpose suffice to say that this report considers two points related to SR 1 67 . a. Eliminate any flow from freeway to the wetlands. b. Eliminate the numerous pipe crossings from the wetlands under the freeway to the west side and use one controlled outlet. Streams There is at least one stream which is going to be affected by this project. Flood Plain This project does affect Green River Flood Plain. Channel Chancres Some improvements to existing channels will be required. Culverts Existing culverts under the freeway will be evaluated and added as required. A major outlet from Panther Creek Wetlands as a part of P-9 Channel is anticipated. , Ditches No work is anticipated. Enclosed Drainage The proposed elimination of enclosed piping in the vicinity of the Panther Creek Wetlands will have to be closely evaluated. For construction of new piping see below. Gutter Design In order to prevent the freeway runoff entering the Panther Creek Wetlands it will be necessary to construct a curb from South i +� 0 180th Street to SR 405 . This in turn will mean construction of new enclosed drainage including catch basins . Some of the existing pipes crossing the freeway to the west may have to be used to convey the freeway runoff. Existing Utilities This project does not interfere with any existing or planned utilities .