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Home My WebLink AboutSWP272862(3) 1 - r 1 sue' 4� Via. 1 � � s rJ z � o 1 * 1908 ' South 180th Street Grade Separation Final Technical Information Report ' Submitted to City of Tukwila Public Works Department Tukwila, Washington Submitted by BERGER/ABAM ' E N G I N E E R S I N C. rJob No. A00084 March 2001 1 FINAL TECHNICAL INFORMATION REPORT South 180th Street Grade Separation Submitted to City of Tukwila Public Works Department Tukwila, Washington March 2001 Submitted by BERGEIUABAM Engineers Inc. 33301 Ninth Avenue South, Suite 300 Federal Way,Washington 98003-2600 Job No.A00084 FINAL TECHNICAL INFORMATION REPORT SOUTH 180TH STREET GRADE SEPARATION TABLE OF CONTENTS SECTION PAGE 1.0 Project Overview ............................................................................................................ 1 2.0 Preliminary Conditions Summary and Off-Site Analysis ..................................... 6 3.0 Flow Control and Water Quality Facility Analysis and Design ........................... 10 4.0 Conveyance System Analysis and Design ................................................................. 15 5.0 Special Reports and Studies ........................................................................................ 20 6.0 Basin and Community Plan Areas .............................................................................. 21 7.0 Other Permits .................................................................................................................. 22 8.0 Erosion/Sedimentation Control Design ..................................................................... 23 9.0 Bond Quantities Worksheet, Retention/Detention Facility Summary Sheet, andDeclaration of Covenant ....................................................................................... 24 10. Maintenance and Operations Manual ....................................................................... 25 Final Technical Information Report A00084 South 180th Street Grade Separation ii April 1999 1.0 PROJECT OVERVIEW South 180th Street, an east-west principal arterial located in the Tukwila, Renton, and Kent areas of the Green River Valley,will be reconstructed to provide a grade separation between vehicular traffic and railroad tracks. The proposed roadway with four lanes, Class III bicycle route, curb and gutter, and sidewalks will pass under the existing railroad tracks and Interurban Trail. The project location and project limits are shown on the vicinity map in Figure 1. A system of catch basins and closed lines is proposed to collect and convey runoff. The runoff collected from the depressed roadway will be pumped to a new stormwater facility. The project will add approximately 0.377 acres (16,422 square feet)of new impervious surface to the site. Following is the summary of the surface areas of the project. Existing Proposed Net (increase) Impervious area(sidewalk+wall) 0.122 acres 0.458 acres 0.336 acres Impervious area(roadway) 1.294 acres 1.335 acres 0.041 acres Total impervious area 1.416 acres 1.793 acres 0.377 acres Pervious area 0.502 acres 0.125 acres Total project area 1.918 acres 1.918 acres Water quality and water quantity controls are required for this project. q Y q Y q P J Final Technical Information Report A00084 South 180th Street Grade Separation 1 March 2001 \ W pY K� RppY J INTERURBAN ` J 405 AVE S P �f �\ SW 16TH ST Lrl j s `r'` 167 w . a 21ST o ST w j z o + u a � + ' N SW 27TH ST STRANDER BLVD PROJECT } LIMITS > CD CD _J D 41 O \ ; ; 1 w Ao ' >� f w a > a ' SW 34TH ST t � w w TUI(WILLA o ' ; a O Y a f a � I I81 SW 41ST ST w s i RENTON ' 180TH — _ RD SE ST SE 43RD ST GpR� 5 +{ (S 180TH ST) 82n S �p vAl a j V N ' z } ti + j > a 1 a CY t � x F- 1 t H o m � � a me 1 � � 1 p ;U ) KENT , 1 I source: Vicinity Map BERGER/ARAM Engineers,Inc. 1999 Figure 1 South 180th Street Grade Separation King County Department of Development and Environmental Services TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND Part 2 PROJECT LOCATION AND PROJECT ENGINEER DESCRIPTION, Project Owner Project Name City of Tukwilla Dept. of Public Works_ South 1801h Street Grade Separation Address Location _6300 Southcenter Blvd, Suite 100 Township 23N Tukwilla, WA 98118 Range 4E Phone 206 433-0179 Section 36 Project Engineer Chris Walcott Company BERGER/ABAM Engineers Inc. Address/Phone 206 431-2300 Part 3 TYPE OF PERMIT Part 4 OTHER REVIEWS AND PERMITS APPLICATION Subdivison DFW HPA V Shoreline Management Short Subdivision ✓COE 404 Rockery y/ Grading DOE Dam Safety Structural Vaults Commercial FEMA Floodplain Other Other JARPA COE Wetlands Part 5 SITE COMMUNITY AND DRAINAGE BASIN Community N/A Drainage Basin Springbrook Creek Part 6 SITE CHARACTERISTICS River Floodplain_FEMA (see Fig. 2)_ Stream Springbrook Creek, and Mill Creek_ Wetlands See Wetlands Study Critical Stream Reach Seeps/Springs Depressions/Swales High Groundwater Table Lake Groundwater Recharge Steep Slopes Other Final Technical Information Report A00084 South 180th Street Grade Separation 3 March 2001 Part 7 SOILS Soil Type Slopes Erosion Potential Erosive Velcoties P Woodinville Silt Loan_ 0—3%_ moderate_ Puyallup Fine Sandy Loam 0—3%_ moderate Urban Land 0—3% moderate Additional Sheets Attached Part 8 DEVELOPMENT LIMITATIONS REFERENCE LIMITATION/SITE CONSTRAINT Ch. 4— Downstream Analysis r Additional Sheets Attached Part 9 ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION Sedimentation Facilities ✓ Stabilize Exposed Surface Stabilized Construction Entrance (/ Remove and Restore Temporary ESC Facilities I/ Perimeter Runoff Control Clean and Remove All Silt and Debris ►/ Clearing and Grading Restrictions Ensure Operation of Permanent Facilities Cover Practices Flag Limits of SAO and open space 1/ Construction Sequence preservation areas Other Other L Final Technical Information Report A00084 South 180th Street Grade Separation 4 March 2001 Part 10 SURFACE WATER SYSTEM Grass Lined Tank Infiltration Method of Analysis Channel Vault Depression SBUH, RATIONAL I/ Pipe System Compensation/ Energy Dissapator Flow Dispersal Mitigation of Open Channel Wetland Waiver Eliminated Site Dry Pond Storage Stream Regional ✓ Wet Pond Detention ' convey Brief Description of System Operation Catch basins and closed lines collect and v runoff to pump station Runoff is lifted to pond for WQ and flow control Facility Related Site Limitations Reference Facility Limitation Part 11 STRUCTURAL ANALYSIS Part 12 EASEMENTS/TRACTS Cast in Place Vault Drainage Easement ✓ Retaining Wall /Access Easement Rockery>4' High Native Growth Protection Easement Structural on Steep Slope Tract Other Other Part 13 SIGNATURE OF PROFESSIONAL ENGINEER I or a civil engineer under my supervision have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attachments. To the best of my knowledge the information provided here is accurate. Signed/Date r i� Final Technical Information Report A00084 South 180th Street Grade Separation 5 March 2001 2.0 PRELIMINARY CONDITIONS SUMMARY AND OFF-SITE ANALYSIS The existing drainage system consists of two separate closed pipe systems, one on either side of the tracks. On the west side,the runoff collected along South 180th Street is conveyed to the system on 72nd Avenue South. East of the tracks, all runoff is collected and eventually discharged to Springbrook Creek via a 36-inch outlet. There are no water quality or water quantity controls for the roadway runoff. The portion of the project adjacent to Springbrook Creek is in a FEMA floodplain. See Figure 2, FEMA Floodplain. The entire project lies within a watershed defined by the City of Kent as Springbrook,Mill, and Garrison Creek Watershed. See Figure 3 for the watershed boundary. Springbrook Creek crosses South 108th Street via a 12-foot by 19-foot elliptical metal culvert located about 500 feet east of the tracks. The subbasins and drainage systems are described in more details in the following sections. Schematics of existing and proposed subbasins boundary are shown on Figure 4. Subbasin West 72nd Avenue South (Station 11+20) to Railroad Tracks (Station 16+10) Runoff from the roadway and few adjacent properties is collected along South 180th Street and conveyed to a 12-inch trunk line on 72nd Avenue South. This system flows south to South 182nd Street,then east under the railroad, and finally discharges to Mill Creek,a tributary to Springbrook Creek. Subbasin East Railroad Tracks (Station 16+10) to End of Project(Station 22+40) Roadway runoff from this section is collected by a system of catch basins and conveyed to a deep system of 36-inch RCP located on the north side of the road. The 36-inch RCP system also drains the off-site areas adjacent to South 180th Street. Flow from the 36-inch RCP system discharges to Springbrook Creek at a location about 30 feet north of South 180th Street. Final Technical Information Report A00084 South 180th Street Grade Separation 6 March 2001 i > soulHv, s� ,cr ssTH sTReT Z — NM337 }I BOUIf.VARD i C South Center ZONE AE Pimp Station i CITY OF TUKVUILA } I ,�'�— w ca 0 530091 CITY OF RENTON 530088 + � m r z ZONE X ZONE AE 1 =Q( f L 0 CID o ALAt cc *— r BRIDGE --- - DRIVE -------------__ �._. _� 1 � / 0 Q i SOUTHb"BEST 41ST STREET ��wu S 7B S _ 'A O K ZONE X U) W Z R00K z Y i Q 7- Bike TrailI bpi i Q ,Bridge u �r Grp 2 P� Sw 27 aaRD CITY OF TUKWILA STREET 'RM339 Sautr+~ ._ 180TH CITY OF RENTON J P� 9y a CITY OF KENT _ ` �«— RM347 CITY OF KENT STREET U S 181ST S 181ST N STREET STREET ZONE AE �rti z uj roatxidge 70 ZONE AE z N� Kent Bike TfH,? � ?� "y 36 � STREET 31 SOUTH 182ND �Q CA a a CITY OF KENT —ZONE X 530080 ZONE AHD o° (EL 17) J a 40 1 s FLOODING EFFECTS FROM eu w ZONE X ZONE AE SPRINGBROOK CREEK ZONE X c�z= 14fi11 Creek } r,� Y ' ZONE AE ZONE AE o ZONE AE-- s: ry - !! 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I •�'�' R {r' �4�i t � �,3 _�- .va - �k I i G, �. •1)Dmnkr \M rl r� - S! .4 - 1 1 .- ...,.,. '�.... O Ge■n• pi i'/'�%�+I'xPIL`7tih'� .:14 '��..II= �-".. 4 _1 S,d i� '�".'� .. ... _.-._ -- --" "- 2 c f t i f 1•III E t` =r, 200 21 ,_ ;Y cer . t k •'16n: \ -+° •sh -- C _t _ min_ _ k - - - - Rsrn �' r I• I�� 4 Ll 1_, rtS�', 28- _T * :1 '.: 28 , I �o P27'^ I 30 L I �1 ! S - In'•" 1 X r' tt :.. bdd 37 .. `t"' ir•:i -3. .-$"` c:. •r• .:i' `,. w 1• ...,aur _'i' 31 ,r -•---•-- - ♦I' ••`,` Tlunea 32 ` '\ 33 3 North 43 source: Springbrook Creek Watershed Boundary Harza Northwest Inc. 1994 South 180th Street Grade Separation Figure 3 eel G� Existing Subbasins tooµ 3 Cn ai a discharges to creek ° ° O S. 180th St r = cn 0 0 2'x 19 oN•a + culvert u Qi— > a- N O N v Q > o N a_ Q O Y c ° N g C: v o o r o 03 V) o o c Co Nm N W u asin es u asin as drain south then east to Mill Creek G� ee* o`� Proposed Subbasins SPt\�oa�o / N ° WQ & Flow Q copn nrdol discharges o to creek Pump o S. 180th St444 } = O a N 12'x19' �* t N o N culvert + + .o _ N jQ _±a_ N N ai C c 0 O O O Q 71 N O C CD 0 N N (n LJ pia cn m Subbosin Subbasin East West drain south then east to Mill Creek ® Contributing area Flow line Source: Subbasins BERGER/ARAM Engineers,Inc. 1999 South 180th Street Grade Separation Figure 4 3.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN Flow Control The detention facility was designed to meet Level 1 Flow Control Standards as specified in the King County Surface Water Design Manual(KCSWDM, 1998). The detention pond was sized to detain the proposed peak discharge rates to the limit of the existing discharge rates for the two-year and ten-year storms. Hydrologic models for detention facility design were developed using the SBUH method with 24-hour storm events, and Type la Hyetograph as implemented by the WaterWorks computer program. Table 1 shows the peak flow rates for the existing and proposed condition of roadway in Subbasin East and the required detention volume. Table 1. Subbasin East Peak Flows Existing Proposed Pond Limits of drain area Station 16+10 to 22+40 Station 12+24 to 22+40 Pervious area 0.502 acre 0.000 acre Impervious area(roadway) 0.909 acre 1.516 acres Impervious area(offsite) 0.280 acres Two-year flow 0.44 cfs 0.84 cfs 0.44 cfs Ten-year flow 0.71 cfs 1.26 cfs 0.71 cfs 100-year flow 1.05 cfs 1.75 cfs 0.96 cfs Detention volume 2374 cf Right-of-way required 0.5 acres WaterWorks outputs are attached at the end of the section. Water Quality Water quality facility was designed to treat the runoff from the total roadway surface area using the method listed in the KCSWDM for basic wetpond. Computations for the required volume are attached at the end of this section. Combined Detention and Wetpond The new pond was designed using the guidelines listed in the KCSWDM for combined detention and wetpond with 3H:1V interior slopes, 2H:1V exterior slope, and 1 foot of freeboard. A permanent pool of water at the bottom of the pond will provide water quality treatment while a live storage at the upper level provides detention capacity. An emergency overflow was provided to discharge 100-year flow for developed condition. An access ramp of 12 feet wide was provided to the wetpool cell at a maximum grade of 15 percent. Final Technical Information Report A00084 South 180th Street Grade Separation 10 March 2001 SOUTH 180TH STREET GRADE SEPARATION DETENTION POND DESIGN (65' ROADWAY SECTION) Project Precips [6-month] 1.28 in [2 yr] 2.00 in [10 yr] 2.90 in [25 yr] 3.40 in [100 yr] 4.00 in [other] 1.27 in BASLIST2 [Existing] Using [TYPEIA] As [2 yr] [Existing] Using [TYPEIA] As [10 yr] [Existing] Using [TYPE IA] As [100 yr] [Proposed] Using [TYPEIA] As [2 yr] [Proposed] Using [TYPEIA] As [10 yr] [Proposed] Using [TYPEIA] As [100 yr] LSTEND BasinlD Peak 0 Peak T Peak Vol Area Method Raintype Event ------- (cfs) (hrs) (ac-ft) ac /Loss Existing 0.44 7.83 0.1563 1.41 SBUH/SCS TYPEIA 2 yr Existing 0.71 7.83 0.2489 1.41 SBUH/SCS TYPEIA 10 yr Existing 1.05 7.83 0.3674 1.41 SBUH/SCS TYPEIA 100 yr Proposed 0.84 7.83 0.2662 1.80 SBUH/SCS TYPEIA 2 yr Proposed 1.26 7.83 0.4004 1.80 SBUH/SCS TYPEIA 10 yr Proposed 1.75 7.83 0.5649 1.80 SBUH/SCS TYPEIA 100 yr BASLIST [TYPE1 A] AS [2 yr] DETAILED [Existing] [Proposed] LSTEND Drainage Area: Existing Hyd Method: SBUH Hyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur 24.00 hrs 1 Area CN TC Pervious 0.5020 ac 79.00 0.11 hrs Impervious 0.9090 ac 98.00 0.06 hrs Total 1.4110 ac Supporting Data: Pervious CN Data: 79.00 0.5020 ac Impervious CN Data: 98.00 0.9090 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet 20.00 ft 2.00% 0.1500 3.42 min Shallow 370.00 ft 2.00% 27.0000 1.61 min Channel 200.00 ft 0.50% 42.0000 1.12 min Channel 100.00 ft 2.00% 42.0000 0.28 min Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet 32.00 ft 2.00% 0.0110 0.62 min Shallow 370.00 ft 2.00% 27.0000 1.61 min Final Technical Information Report A00084 South 180th Street Grade Separation 11 March 2001 Channel 200.00 ft 0.50% 42.0000 1.12 min Channel 100.00 ft 2.00% 42.0000 0.28 min TC of 3.63 min <5 min, program will use a tc of 5 min in computations. 100 yr Flow Time Volume Summary: 1.0530 cfs 7.83 hrs 16003.29 cf - 0.3674 acft Drainage Area: Proposed Hyd Method: SBUH Hyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur 24.00 hrs Area CN TC Pervious 0.0000 ac 0.00 0.00 hrs Impervious 1.8000 ac 98.00 0.04 hrs Total 1.8000 ac >� Supporting Data: Impervious CN Data: PAVED 98.00 1.8000 ac Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Sheet 32.00 ft 2.00% 0.0110 0.62 min Shallow 260.00 ft 5.00% 27.0000 0.72 min Channel 180.00 ft 3.00% 42.0000 0.41 min Channel 150.00 ft 0.50% 42.0000 0.84 min TC of 2.59 min <5 min, program will use a tc of 5 min in computations. 6-month Flow Time Volume Summary: 0.5033 cfs 8.00 hrs 7249.07 cf - 0.1664 acft HYDLIST SUMMARY [out-2yr] [out-10yr] [out-100yr] LSTEND HydID Peak Q Peak T Peak Vol Cont Area (cfs) (hrs) (ac-ft) (ac) out-2yr 0.44 8.17 0.2661 1.8000 out-10yr 0.71 8.17 0.4004 1.8000 out-100yr 0.96 8.17 0.5648 1.8000 STORLIST 1 [POND1] LSTEND Node ID: POND1 Desc: DETENTION POND - DOE Start El: 23.0000 ft Max El: 50.0000 ft Contrib Basin: Contrib Hyd: Length ssi ss2 Width ss3 ss4 70.0000 ft 3.00h:1 v 3.00h:1 v 34.0000 ft 3.00h:1 v 3.00h:1 v DISCHLIST [D-001] LSTEND Control Structure ID: D-001 - Multiple Orifice Structure Descrip: POND1 MULT. ORIFICE Start El Max El Increment 22.9000 ft 50.0000 ft 0.10 Orif Coeff: 0.62 Final Technical Information Report A00084 South 180th Street Grade Separation 12 March 2001 Lowest orifice: 5.0 in IE 20.90 out to 2nd: 0.44 ft Second orifice: 3.0 in IE 23.34 2nd to 3rd: 0.20 ft Third orifice: 2.5 in IE 23.54 Oulet elevation 22.90 Top of 12" Dia. Riser elev 24.0 RLPCOMPUTE [POND1-RLP] SUMMARY 2 yr Match Q: 0.44 cfs Peak Out Q: 0.44 cfs - Peak Stg: 23.33 ft -Active Vol: 820.01 cf 10 yr Match Q: 0.71 cfs Peak Out Q: 0.71 cfs - Peak Stg: 23.58 ft-Active Vol: 1489.54 cf 100 yr Match Q: 1.05 cfs Peak Out Q: 0.96 cfs - Peak Stg: 23.89 ft-Active Vol: 2374.47 cf Final Technical Information Report A00084 South 180th Street Grade Separation 13 March 2001 Project 5, 190 TP ST- Sheet of Job Number.. 4 BERGER/ABAM Subject�)ATF_R- (,?4UA L 1 T Y Designer_ I A D Date 2.�20'01 V, ( o,q A 0,�s �} � 0, 1 A{ + 0, 01 A R ) 1� KC D ► t3 IC- E Doti,e sw M �,4 � , � as � T t A; = 5S , 170 SF PROPOSED POA-bWA\i OUFFIC-E J A _ At, _ AO = 0 P,, _ 0 47 Vl2 = 0, � C 5$ , 170) x 4-7 = �2 , 05 1 CCF Vb = x V, 3 X o2, 0 51 4 = 3 , VOL-U A4-E FA(-TOY2 F'GR B/ISI C- f aN D G, 1 S 3 G1= PO►JD C,ALCULATON AND ACAJ MFA �UX-F, -IE1VT Via = 6 , / 9am LF > V6 �{L-L- SLOPS S = 3 ; ► Final Technical Information Report A00084 South 180th Street Grade Separation 14 March 2001 4.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN General The proposed conveyance system was analyzed and designed in accordance with the current guidelines listed in the KCSWDM. The Rational Method was used to compute the 25-year peak discharges for all pipelines, and the 100-year peak flow for the pump capacity. Table 2 shows the precipitation coefficients and calculated peak flows. Gutter flows and inlet spacing were determined by using the method listed in the Washington State Department of Transportation(WSDOT) Hydraulics Manual. The Backwater Analysis method was used to analyze the new system to verify adequate capacity. Computations are attached at the end of this section. Table 2. Precipitation Intensity Coefficients for Rational Method Recurrence Interval 24-Hr Precipitation aR bR Flow 25-Year 3.4 inches 2.66 0.65 4.183 cfs 100-Year 4.0 inches 2.61 0.63 5.012 cfs Source: King County Surface Water Design Manual Runoff from South 180th Street will be collected by catch basins along the gutter on both sides of the roadway. No modifications are proposed for the off-site lines. Subbasin West 72nd Avenue South (Station 11+20) to Station 12+25 No modifications are proposed to the existing system west of 72nd Avenue South. The existing roadway storm sewer system east of the intersection must be removed. New catch basins and 12- inch pipe will collect and convey runoff from Station 12+25 to the west. This system will be tied to the existing system on 72nd Avenue South. Subbasin East Station 12+25 to Springbrook Creek Culvert(Station 21+84) Runoff will be collected by catch basins along the gutter on both sides of the roadway. The mainline 1 of 12-inch pipe will convey the flow to the pump station located on the north side of the road, approximately at Station 18+00. The station will have two pumps that alternate pumping the runoff. This allows for even wear on both pumps and provides for a backup pump during the maintenance or replacement of one pump. The runoff then will be pumped to the new stormwater facility located 50 feet north of South 180th Street and east of the tracks for water quality and water quantity control. Flows from the new facility will be conveyed via 12-inch pipe to the existing 36-inch RCP system and discharge to Springbrook Creek at the original outfall. Springbrook Creek Culvert(Station 21+84) to End of Project(Station 22+40) No major modifications are proposed to the existing system. Final Technical Information Report A00084 South 180th Street Grade Separation 15 March 2001 400 Project 1 S6 TH Sheet _ of Job Number4- BERGER/ABAM Subject PFA K F L- 1) Designer >✓1 E N G I N E E R S I N C. FOK CO M EYA•QC E Date��O 1 ;>E . KC,SW DM lC119) kA DOM A L ME rHOb T = L/ Coo KR � ) L = 4f220 _ bR KR a0 L _ ap,/(T) L = PU S A = I,7 Ac, CIA G o, c/o T = 4.60 (GO x 20 x �Ir�, 04�. � = 1, S 7 M/til, LET T - G , 3 MW- c, r P= S,4 inlcff r = 3 4 x 0, �<Od = . 73 4 = o, q X 73 4 x . 7 - 4 . 19 3 CPS Z = 4 , 0 X 0, S11 = 3,27& C� = ago x 3, 2,7r x 1, 7 FS z z so 6-PNI Final Technical Information Report A00084 South 180th Street Grade Separation 16 March 2001 Project Sheet of 7 Job Number A 3 , r BERGERIABAM Subject t>P,,A I /A Designer E N G I N E E R S I N C. � T T Date � 11 /Ic'I R F-F*FKFQC�E �1!,A�JUAL- 4, F- T L LL I I TfZAv -AVE. 77 JO- q. 5 x x C. It �15 115 < 0, 12, OK Final Technical Information Report A00084 South 180th Street Grade Separation 17 March 2001 HIGHWAY DRAINAGE(English Units) T= 5 Project Name: S. 180th St.Grade Separation m= 6.89 Project Number: A00084 n = 0.539 S.R.: NA C= 0.9 Designed By: MD I= 2.89384 (25-yr 24-hour storm) Date: 1/5/2001 GW= 1.67 Width= 32.5 (1/2 of roadway width+sidewalk) dmax= 0.19' (depth of flow at face of curb) Zmax= 9.5 (from curb to 1/2 of lane) Sta. Width Distance Delta Q I Sum Q1 Sloe ISuperIG.W.1 d I Zd I V I Q bp 1 12+15.00 ---- ------- ---- ---- ---- ---- --- --- --- --- ---- ------------ 14+11.00 32.5 196.00 0.381 0.381 6.00% 0.02 1.67 0.07 3.51 3.50 0.068 15+70.00 32.5 159.00 0.309 0.377 3.50% 0.02 1.67 0.08 3.87 2.89 0.084 16+60.00 32.5 90.00 0.175 0.259 1.00% 0.02 1.67 0.09 4.25 1.67 0.068 16+90.00 32.5 30.00 0.058 0.127 0.10% 0.02 1.67 0.10 5.01 0.60 0.043 22+80.00 ---- ------- ---- ---- ---- ---- --- --- --- --- ---- 20+50.00 32.5 230.00 0.447 0.447 3.75% 0.02 1.67 0.08 4.07 3.12 0.109 18+07.00 32.5 243.00 0.472 0.582 3.50% 0.02 1.67 0.09 4.56 3.30 0.172 17+20.00 32.5 87.00 0.169 0.341 0.75% 0.02 1.67 0.10 4.98 1.64 0.115 16+90.00 32.5 30.00 0.058 0.173 0.10% 0.02 1.67 0.11 5.63 0.66 0.068 Reference: WSDOT Hydraulics Manual 5.4,5.5 Final Technical Information Report A00084 South 180th Street Grade Separation 18 March 2001 m � � a 0 m�. '-1 (D r3 CD O ♦y (D o .. �o m � 'Cl w 0 0 0 _ ---Street Grade Separation _ ENTR ENTR. EXIT OUTLET INLET�APPR I BEND Backwater Calculation t- Y - South 180th � I P FREE- BARREL - - IJUNC I A00 + STRUCT M DESIGN - LAT. PIPE 25-PIPE PIPE -n__ -Ke Kb F. Kj OUT IN AREA! L �-_ -Wt1 - I--- - __-* -�-ELEV. ELEV. HEAD I LOSS HW RIM FREE- Y _ ` O -. {� HEAD I HEAD HEADFROM TO 02 Ot O3 - ( ft VE; VEL ' tt D+n /2 TWRIn T.` EL: LOSS LOSS, LOSS EL. EL BOARD SIZE LENGTH SLOPEI EL. EI HEAD ar. ELLOSS EL tt tt CNRL CNnRL (tt) t (tt) ( ) (ft) (CIS) ) I ) -SIZE ! { ). ( ). ------ VEL HEAD crs i (Crs crs in tt rue e) ltt) -1 ) (TM�s {tt) O _{ ) ( L� { ) O ---{) , ..- 1 0.01 0.00' 1.30 t 74 ' 0.22 r 0.14 _ 2.95 3.45 0.139 0.00 0 00 3.31 7 18 5.85 P.S. 15 4.140 d.140 0 00 12 15 001 0.013 0 012 0 5 1 50. 0.79 5.27 0 43 0.85 0.93 y 2 50 0.171 2.67 0.22 - 0 43 3 32-� 3.20 0 139 0.00 0 00 3.18 9 03 0 00�..-.12 l_ 87 001 0,010 0.012 0 5 0.01 0 00 1,60 2 50 0.79 1 2.99 0 14 0.64 0.82_ 2 42 0 319 2 _.. 3.87 15 13, 2.350 2.350 - 0.62 _ 3 42_I 0.110 3.53 0.07 0 1.4 I 3.74 3.95 0.026 0.00 0.00 3_.92 7.05 3.13 13 11 1.010 1.010'0,00 12 30.W 0.010 0.012 0.013 0.012�.0 5,0.01''.0.001 3.60 3 90 0.79 1 29 I 0 03 0.42 _ _. � I _ , 7.18' 2.72 �-' 1 1 9 - 0.71 4.31 0.020 4.33 0.01 0.03 4 37 !"4 50 0.042 0.00 0.00 4.46 - 900 0.79 1.22 002 _0.41 0.71 4.71 0.055 4.76 0.01 0.02 _ 4.80 6.30 0.0161 0.00 000 6.28 9.16 2.88 �. 7 0.960_ 0.960 0�', 12 159001 0059 0.012 OS 0.01 01 I'000 5.80 390 1,.. -. f_658_+ 14.50 :_ _ 1144617.61� 3.15 7 5 0.800 0.800 0.00 _ 1 0.79 1.02 1 0 02 0.38 0.69 1 6.49 0 068 6.56 0.01 0 02 0.042 0 00 0 00 __ 0.79 I 1 64 i-0.04 0.48, _0.74 15 74 0 094 {15.83 0 02. 0 04_1_15 90 20.50. 0.000 j 0.00 �) 0 00 20 50 22 61 2.11 0.059 0,012 O S 0 01 0 00 15 Do 20 00 4 0 00 r 12 1 B5 00'1 0.010 1 0.012 O S O Ot l_0 00 4.50 5.00 0.79 1 27 1o.63 t ._ _t _ - , ' 3 55 5 3 0.500 L289 5.481 9.03'i 15 16 1.000 1.000 0 00 12 50 30 0 03 0.42 0.71 2 50 0 033 2.53 0 01 0 03 2 57 5 50 0.016 0 00 0 00 13.10 0.79 1.02 0.02 0.38 0.69 5.79 0.060 t 5.85 0.01 0 02 5.87 13 60 0.002 0.00 0.00 13.60 16.23 2 63 a _ 0,800 1 0.800 1 0.00 I 12 141 00� 0.057 0.012 0 5}0.01 0 00 5 10 f r -0.00' - + 0.500 0.300 0.20 12 102 00 0.044 0 012 i 0 5 0.01 0 d2 L13780118.30 0.79 0.38. _0.23�0.6.2_ 14 42� 0.008�14.42 0.00 0.00 14.422?�1 B 80 0.000 0.00 0.00 18 B01 20.9 2.10 �- - __ 1 i 16jjI 18 20 } Re Ina Coun Surface Water Design Manual,and WSDOT Hydraulics Manual I >n �a 8� 5.0 SPECIAL REPORTS AND STUDIES Because there are no new roadway developments proposed within the floodplain, a flood hazard study is not needed for this project. However,the project will impact the wetlands located within the project site thus impacting their flood storage capacity. The impacts to these wetlands will be analyzed in the following sections. See South 180th Street Grade Separation Wetlands Study, (BERGER/ABAM Engineers Inc., 1999)for detailed descriptions of the wetlands. The project proposes to fill part of the wetlands located between the existing tracks to construct the shooflies for the railroad tracks. Approximately 1.09 acres of Wetland B,which is located north of South 180th Street,will be filled. Assuming that the displaced volume of 170,000 cubic feet of water in this impacted area is added to the remaining of 24.5 acres of Wetland B and the connecting wetlands, the water level would be raised by 1.9 inches. This small change in water elevation will not create or aggravate any existing drainage problem in the Springbrook Creek floodplain. Wetland C,which is located between the existing tracks and south of South 180th Street will be completely filled. Because Wetland C is less than 0.1 acre in size, and its flood storage capacity is low,impacts to downstream flooding is minimal. A wetland mitigation plan was developed for the project to compensate for impacts on Wetland B and Wetland C at a ratio of 1.5 to 1 (area created to area impacted). The impacted flood storage capacity is thus compensated. Other Studies A geotechnical engineering report, studies of wetlands, streams, and wildlife were completed for this project. Final Technical Information Report A00084 ' South 180th Street Grade Separation 20 March 2001 6.0 BASIN AND COMMUNITY PLAN AREAS Not applicable for this project. i 1 Final Technical Information Report A00084 South 180th Street Grade Separation 21 March 2001 7.0 OTHER PERMITS The required permits needed for this project are listed below. Grading DFW HPA COE 404 JARPA Final Technical Information Report A00084 South 180th Street Grade Separation 22 March 2001 8.0 EROSION/SEDIMENTATION CONTROL DESIGN ' A Temporary Erosion and Sediment Control Plan will be submitted with the final construction plans to the City of Tukwila for approval with the construction permit application. Construction phasing will minimize the extent and duration of areas exposed. Mulching and seeding disturbed areas will be done as soon as grading is completed. Filter fabric fences will be installed downslope of all construction areas and sediment traps will be used to protect new and existing catch basins. Runoff from the construction site will be conveyed to the sediment pond for settling before discharge to the existing outfall. r 1 i 1 1 Final Technical Information Report A00084 South 180th Street Grade Separation 23 March 2001 ' 9.0 BOND QUANTITIES WORKSHEET, RETENTION/DETENTION FACILITY SUMMARY SHEET AND DECLARATION OF COVENANT ' Bond Quantities Worksheet The stormwater facilities will be bonded per the requirements of the City of Tukwila. 1 i 1 1 1 1 1 1 1 i Final Technical Information Report A00084 South 180th Street Grade Separation 24 March 2001 10.0 MAINTENANCE AND OPERATIONS MANUAL ' A Maintenance and Operations Manual will be prepared for the stormwater facilities as outlined the KCSWDM. The Maintenance and Operations Manual for the pump station will be prepared according to the manufacturer requirements. Final Technical Information Report A00084 South 180th Street Grade Separation 25 March 2001