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02869 - Technical Information Report
� ETERSON _ . ...�� �..r._...._.__ :��:� �. :, C ONSU LTI NG ��- tY�`` -�� � - s �1PR 1 7 ZOOt7 � E �L�i��l�� ������ioi� � , € I � $ � _�: . _ _ � � � a �� TECHNICAL INFORMATION REPORT I Pacific Gulf Warehouse I�� City of Renton File No. LUA99-lO5,SA-H,ECF Owner/Developer: Pacific Gulf Properties, Inc. 4220 Von Karman Avenue, 2nd Flr Nerwport Beach, CA 92660-2002 (949) 223-5000 Prepared by: ��`�o� w�sy'� Keith A. Litchfield, P.E. � � o • z J T �,Y � PET E RSO N '`���j�� r� ONSULTING S�ON , �P�REs 2-io- o� 4030 LAKE�NASHINGTON B LVD. NE,SUITE 2QO �""� KIRKUND,WASHINGTON 9$O33 OFFicE(425) 827-5874 Fnx(4251822-721 6 April 13, 2000 PCE Job No. TREC-0019 i I TABLE OF CONTENTS TABLE OF CONTENTS .........................................................................i I. PROJECT OVERVIEW ...........................................................:............ 1 Technical Information Report Worksheet .......................................2 11. CORE REQUIREMENTS ...................................................................... 5 A. Core Requirement #1 : Discharge at the Natural Location ...................5 B. Core Requirement #2: Off-Site Analysis ...........................................5 C. Core Requirement #3: Runoff Control ............................................ 5 D. Core Requirement #4: Conveyance System .................................... 5 E. Core Requirement #5: Temporary Erosion & Sediment Control............ 5 fll. SPECIAL REQUIREMENTS .................................................................. 5 IV. EXISTING CONDITIONS ..................................................................... 7 V. DEVELOPED CONDITIONS ................................................................. 7 VI. STORMWATER DETENTION / WATER QUALITY SYSTEM........................ 8 A. Storm Water Detention Vault System .......................................... 70 B. Storm Water Detention Pond System ........................................... 10 C. Storm Water Quality System....................................................... 11 VII. CONVEYANCE SYSTEM ANALYSIS and DESIGN .................................. 13 VIII. SPECIAL REPORTS and STUDIES .................................:..:.................. 18 IX. BASIN and COMMUNITY PLANNING AREAS........................................ 18 X. OTHER PERMITS ............................................................................ 18 XI. EROSION/SEDIMENTATION CONTROL DESIGN ..............................�i... 18 APPENDICES APPENDIX A HYDOLOGIC ANALYSES LIST OF FIGURES FIGURE 1 VICINITY MAP FIGURE 3 EXISTING CONDITONS MAP FIGURE 4 DEVELOPED CONDITONS MAP I. PROJECT OVEVIEW The project consists of the construction of on-site infrastructure to support the future construction of a 106,752 SF warehouse located on a 7.39 acre parcel. The site is located at the 3900 block of Lind Avenue SW, south of SW 34th Street Isee Vicinity Map). The site is currently undeveloped and is covered in sparse pasture grass with briars and some bushes situated along the property lines. Slopes on the site range between 1 % and 3%. A wetland borders the site along its east property line. Development of the permanent access to the site will consist of constructing two commercial access approaches from Lind Avenue SW and one each from the commercial access roads that border the site along its north and south property line. Although no significant off-site road improvements will be required, concrete sidewalk and landscaping will be constructed along the west property line. (Jrc�",��j�tiw�ri,3� i2,'�cr� The project site is located within the Black River Sub-basin of the Basin. Stormwater peak rate runoff control and water quality treatment is provided via a combination detention/wetpond for the southern and eastern portion of the site and a detention/wet vault for the northwestern portion. The performance standard of the detention facility is based on the City of Renton's standard of matching the developed 2, 10, and 100 year, 24 hour storm event to the predeveloped 2, 10, and 100 year predeveloped events. Discharge from the detention systems will be made to existing catch basin located to the south and west of the site. Soils within the project area have been classified as Hydrologic Type C based on the site specific soil analysis by Terra & Associates. I .._ � : c'� ... (+ppU� •• .,. ��C VGfIICK � .. , S�1 .��. S� � g SW � 1 H "- ����V� ■ : Sm NTON VILLAGE PL � � 30� �2TM � M7LIDAY �. � ' 1NN ���a� � . "^ v3j �SW ` p v3i 13TM _ �` � � � a' W 5 Z � ST � °tN 5� Z � � 9�: �� t"���,, .:l(ii:; S� ❑ � �<�� �a. < ��'e: _ � � - �L1Xf STR ET '` � ". ,16TH � �< ST: SW Z �, v�wr S' 15TH �, ' 400 ' 16TH ST < �� o � � ST �, aQ- �.,i o( o � c � S 16TH ST c��'/ ` J` r. � � -� < C � � �/' a S � �n `� ,\j �`�. t ""•�•---'.:%;�� � I— . v –�._ -o J y �....•.;.rl,.�, � � �, Q- �BRoo�-��:.;�<>>_ ' o m � ` y � S 18TH � � �'•p �� � °+ SW 19TH ST -��9 v� v, � ST Q.o mo��5 P o � �t�_•( ,.:,.:S 19TH � ST o �TALBOT o z � . t,���..0 PAN7NfR N S 2p` PL v�20TyHICL �\, S Qq ' ��� ` ' < S 2FST S Q �� P PARK 1 Q� � P� ; '� CREfK N ,€ Y SW a�21ST ST ,,, \ t1E7UNOS� `^ � � �' c1�N0 3 ' s 2zro a z4 � � tf� �` N SW 23RD ST S: 23R0 '^ S�, ST s ' � -�� , -'-�T p „+aus 1�S�� � MI i " - �� �� �-rrAsa�ic�� ` . , - � � �. �� t-� pARK�� ��' � S (, J wN 3 ----- - i � r.� e��, � S._ ,a� f '� > Q i- y,t � zatH �`c'a�?yc� 1'�� `'� T � `. .��: i�,. Q > '.� `��n,�1 `� �+ � ,_,,,.,SW ' � 27TH ST � �,. h)�5��11�{1,`�� S�„ 5 �L Q I _� S 27TH � �: 1 ', S �m p 287H �r.(�S 20t� a 5 26TFI . REIrlON ` �WET�ANDS ' —r�! ,t Pt� y�5�'�9j%'"� � �;E 166TH; SE 1 W 29TH ST " ��� `'Q �� s`'�5 0 +�� s � S i ' - , � S� . w: �4��-� � � 30 � �ry Q��� T��T � �, :; PAXIHE \N`. �" S ,5w 3om . 1=------ �T�T ; 29 $T cxrcx SE 31ST ST � Q, a � 33R0 ST �� Mt71'IACS '• S,S1. p�' PL N 32N0 p c � � I . . � h �PL .-r = - � W S �� �i"--- a ��� Fs--: - $W � , � W l c 4TH gT AMNE�, o ,� � i h 34TH 5T S ^ �'t '� ' � c s I�.il:;ic. RENTON. � I Z � CRE�K�J6 �' +� � (� ti H r N�TGINOS;'. I J T RoSE � ' ��J�i �� 37T ST S �� '.� ,�;��� •,� � f ..._ TH �J ,� , , r: � �%��'SW 39�N ST , � S_ CT '�T � �/, .,�J`°.:; <...7�� KETUNDS . ,:;;. � s, s �� 0 f SE i� �> � � � _ � J � SW � (T �y� J:� ., N"/r� I� � 41ST �71 f fi `-� i�✓• blk'��N �— . S I� TM ST � � ���L IfMllt Q� � .,, { � o I ;11 n ' �--+ ,� vu e rr �+�,�-�.. . , . _ 1 VICINIT Y MAP PACIFIC GULF WAREHOUSE FI GURE 1 DWN. BY.• DATE: JOB NO. 4030 L,ake Washin�ofl � ETE RSO N �lvd. N.E., Suite 200 NA 4�14�00 TREC—0019 W I C Q N S U LT I N G Kirkland, w� s�o� ¢ �� , '�'el (425? �27-557� CHKD. BY.- SCALE.• SHEET �� F'a�c i425) �22-7216 NA NONE 1 OF 1 �4 � Page 1 of 2 King County Bullding and Land Development Divtsion TECHNICAL INFORMATION REPORT (TIR) WORKSHEET - . . � - . . . . � . . . ProjectOwner ►�C�FtG �U CF PRoP62T1'rS Project Name ��rG\F��- �a.�31-r V�Ll��1-�OV � Address �ZZO �o�11«RM4�1 ��lE. tS'�PO Location Phone ��°I' ZZ�'S00� gEP��1t � Township Z31�1 Project Engineer �A2T0�.� 'C�R�—G'E , P�E� Range '-��' � Section _30 Company TR��-� � CA MPAN.`�� ' Project Size '��3� AC � Address Phone 4�30 L�.�p,, gl.,�l� Upstream Drainage Basin Size nt P� AC l�t 2K�...AND . . . 0 Subdivision � DOF/G HPA 0 Shorefine Management � Short Subdivision � CpE 404 � Rodcery �Grading � DOE Dam Safety 1�4 �tructural Vaults �Commercial � FEMA Floodplain 0 Other � Other 0 COE Wetlands � HPA . � � - Community ' G�z�( c�� 2E.�1'�O tJ I Drainage Basir��C� Q`v E� S v$_3P�S�N �Q'�-� ��V�� t I -, � River � F(oodplain � Stream '� Wetlands 0 Critical Stream Reach � SeepslSprings li � Depressions/Swales Q HighGroundwaterTable ' 0 Lake 0 Groundwater Recharge � Steep Slopes � Other � Lakeside/Erosion Hazard . I Soil Type Slopes Erosion Potential Erosive Velocities 0 Additional Sheets Attatched ' 1/90 3 Paga 2 of 2 King County BulldinD and Land Development Dhrlslon TECHNICAL INFORMATION REPORT (TIR) WORKSHEET �. . . • . ' � REFERENCE LIMITATIOWSITE CONSTRAlNT � � Ch.4-Downstream Analysis 0 a a a 0 0 Additional Sheets Attatched � MINIMUM ESC REQUIREMENTS MWIMUM ESC REQUIREME(�JTS DURING CONSTRUCTION FOLLOWING CONSTRUCTION � Sedimentation Facilities ,P Stabilize Exposed Surface � �' Stabilized Construction Entrance � Remove and Restore Temporary ESC Facilities � Perimeter Runoff Control [7� Clean and Remove All Silt and Debris � Clearing and Grading Restrictions �' Ensure Operation of Permanent Facifities � Cover Practices 0 Flag Limits of NGPES � Constn�ction Sequence � Other � Other �- � � Grass Lined Channel L� Tank � Infiltration Method of Analysis � Pipe System �' Vault � Depression SSV� Q Open Channel � Energy Dissapator � Flow Dispersal Compensation/Mitigation O Dry Pond 0 Wetland � Waiver of Elimmated Site Storage � Wet Pond � Stream 0 Regional Detention Brief Description of System Operation G6 CbLI.Ec.T1o1J � EaR�kss L t N E fl Sul�A�L�—�1. _�A�1-'C� �� ET�NTIA� t��t0 �8��r1 W�� � OvT'FPtt..t.- �o PuB��c_ s S. Facility Related Site Limitations � Additional Sheets Attatched Reference Facility Limitation I • � .- �], Drainage Easement �Cast in Place Vault � Other �Access Easement � Retaining Wall 0 Native Growth Protection Easement I 0 fiockery>4'High � Tract 0 Structural on Steep Slope � Other • • • • �, I or a civil engineer under my aupervision have visited the site. Actual �� n � site conditions as observed were incorporated into this worlcsheet and the r�� � !� attatchments. To the best of my knowledge the iniormation provided �� • here is accurete. sp�.av.r. �.,. 1/90 II. CORE REQUIREMENTS A. Core Requirement #1: Discharge at the Natural Location The proposed on-site conditions and patterns emulate those of the existing site conditions. The developed on-site runoff will be routed via a catch basin/pipe system within the on-site street/parking areas to two on-site detention facilities. Discharge from these facilities will be conveyed to an existing public storm drain collector system located in Lind Avenue. B. Core Requirement #2; Off-site Analysis An existing 60-inch storm sewer system is located within Lind Avenue and will receive the storm water discharge from the developed site. Details, with analysis, of the off-site system were provided during the preliminary stages of the project and discussed in a report titled Pacific Gulf Warehouse: Preliminary Drainage Report by Peterson Engineers, Inc. dated July 20, 1999. Please refer to this earlier report on file with the City of Renton for a detailed discussion of the off-site drainage system. C. Core Requirement #3: Runoff Control Runoff control will be provided for the warehouse and office facility by constructing two on-site detention facilities sized to release the developed discharge at the predeveloped rate. D. Core Requirement #4: Conveyance System The proposed on-site conveyance system, grass swales and tightline system will route runoff to a detention/water quality facility prior to being released from the site. E. Core Requirement #5: Temporary Erosion and Sedime�t Control Plan An erosion and sediment control plan, which will serve to minimize soil erosion/sedimentation during the proposed site construction has been prepared for approval by the City of Renton. See Section IX of this report for further details of the Best Management Practices to be implemented for the project. III. SPECIAL REQUIREMENTS A. Special Requirement #1: Critical D�ainage Areas The site is located within the Black River Sub-Basin, Green River Basin (See Black River Basin Map in Appendix A). This basin is not defined as a critical drainage area in the 1992 King County Surface Water Design Manual. B. Special Requirement #2: Compliance with an Existrng Master Drainage Plan Not applicable to the Pacific Gulf Warehouse site. C. Special Requirement #3: Conditions Requiring a Master Drainage Plan Not applicable to the Pacific Gulf Warehouse site. � � D. Special Requirement # 4: Adopted Basin or Community Plans The site is located within the Black River Sub-Basin, Green River Basin (See Black River Basin Map in Appendix A). E. Special Requirement # 5: Special Water Quality Controls The proposed project will create approximately 111 ,500 SF of new impervious area subject to vehicular traffic. A wet pond and wet vault have been designed to meet this special requirement. Specia/ Requirement #6-#10 are not applicable to this site. F. Special Requrrement #11: Geotechnical Analysis and Repo�t Terra Associates, Inc., have prepared a Geotechnical Study dated June 9, 1999, copies have been submitted to the City of Renton as part of SEPA submittal. G. Special Requirement #12: Soils Analysis and Report Terra Associates, Inc., have prepared a Geotechnical Study dated June 9, 1999. Copies have been submitted to the City of Renton as part of the SEPA submittal. � I IV. EXISTING CONDITONS The existing site contains sparse grasslands and little vegetation. There are small shrubs and blackberry bushes along the western boundary of the site. A portion of the site, approximately 1 .25 Acres, contains an existing wetland buffer and will not be disturbed as part of this project and is excluded in the detention calculations. There is also a portion in the northern area of the site which can not feasibly be routed through a detention system. The increase in impervious coverage for this area has been accounted for in the detention calculations. The on-site drainage patterns generally sheet flow from the east to the west at relatively flat slopes (1 % to 3%). The existing basin areas have been delineated on the Existing Conditions Map. The hydrologic parameters are summarized in Section VI below. V. DEVELOPED CONDITIONS The proposed site will consist of a 2.45-Acre warehouse and office facility with adjacent parking areas and landscaping. The developed site was divided into three hydrologic basins (See Developed Conditions Map). The northwestern portion of the site comprises hydrologic Basin 'A'. Runoff generated within Basin 'A' will be conveyed via a grass swale and tightline system to a combination detention/wet vault. The southern portion of the site will comprise on-site Basin 'B'. Runoff generated within Basin 'B' will be routed to approximately the midpoint of the southern boundary of the site, into a combination detention/wet pond, via grass swales and a tightline system. The northern most portion of the site comprises . he increase in impervious area in Basin C was accounted for in ;`�decreasing the allowable release rates for Basin B. `----.,_.—_�_---'"_.__..__ ✓ n /VJ y � �/ _T'��-�- ri' L�C �7U��5 r � ��� �,e i'h�-�-� �� �/ r.-.1.�..;.� � � ��r �U ,,a(f � W �.tx � r, , � VI. STORMWATER FACILITIES ANALYSIS and DESIGN A hydrologic analysis of the site was completed in order to determine the required on site detention necessary to account for the increase in the peak storm water release rate for the developed site. The site was analyzed for the pre and post- developed�site conditions under the SBUH hydrograph method using WATERWORKS software by Engenious Systems Inc. Given the topographical constraints of the existing project site, three drainage basins were defined for the project. Basin A defines the area tributary to a detention vault system, Basin B defines the area tributary to a detention pond system, and Basin C is undetained area. The existing pre-developed site basin criteria are summarized below with the hydrologic parameters used in the analysis. The analytical results are presented in the basin summary sheets in Appendix A. Existing Site Analytical Criteiia Basin A Areas Pervious = 1 .41 acres Impervious = 0 acres Soil Type: Alderwood Hydrologic Group: C Curve Number = 85 (KCSWDM Table 3.5.2B, meadow or pasture} Tc = 19.16 min. (see Basin Summary Sheets) Basin B Areas Pervious = 4.12 acres Impervious = 0 acres I Hydrologic Group: C ' Curve Number = 85 (KCSWDM Table 3.5.26, meadow or pasture) T� = 39.88 min. (see Basin Summary Sheets) i Basin C Areas Pervious = 0.40 acres Impervious = 0.21 acres Hydrologic Group C Curve Number: Pervious = 85 (KCSWDM Table 3.5.28, meadow or pasture) Impervious = 98 (KCSWDM Table 3.5.2B, impervious surfaces) �= � , Tc: Pervious = 9.51 min. (see Basin Summary Sheets) Impervious = 5.00 min. (see Basin Summary Sheets) Precipitation: PZ = 1 .95" ' P,o = 2.85" P,00 = 3.85" ', Deve%ped Site Analytical Criteria � Basin A Areas Pervious = 0.20 acres Impervious = 1 .21 acres Curve Number Pervious = 86 (KCSWDM Table 3.5.26, landscaping) Impervious = 98 (KCSWDM Table 3.5.2B, impervious surfaces) Tc � Pervious = 5.00 min. (see Basin Summary Sheets) Impervious = 5.00 min. (see Basin Summary Sheets) Basin B Areas Pervious = 0.76 acres Impervious = 3.36 acres Curve Number Pervious = 86 (KCSWDM Table 3.5.2B, landscaping) Impervious = 98 (KCSWDM Table 3.5.2B, impervious surfaces} Tc Pervious = 5.00 min. (see Basin Summary Sheets) Impervious = 5.00 min. (see Basin Summary Sheets) Basin C Areas Pervious = 0.21 acres Impervious = 0.40 acres Curve Number Pervious = 86 (KCSWDM Table 3.5.2B, landscaping) Impervious = 98 (KCSWDM Table 3.5.2B, impervious surfaces) Tc Pervious = 9.51 min. (see Basin Summary Sheets) Impervious = 5.00 min. (see Basin Summary Sheets) �� A. Stormwater Detention Vault System The detention vault system has been designed with a 2.45 faot active storage depth and 2.65 foot water quality storage depth. The active storage depth is limited by available grade. The vault outfall will be into an existing 12" storm drainage stub approximately 25 feet southwest of the vault. The detention vault has been designed to restrict developed outfiow from this project basin based on the City of Renton criteria. This is accomplished using a three-orifice system on a standard FROP-T riser section. The developed 2-year, 10-year and 100- year 24hour events are detained and released at the respective predeveloped 2-year, 10-year and 100-year 24-hour rates. The control structure is designed to pass the 100-year peak runoff for the developed conditions through the riser. Analytical details (i.e. elevations, orifice diameters, detention volume, release rates etc.? are provided in the WATERWORKS output data sheets provided in Appendix A. Detention vault peak volume & outflow Required Storage Volume = 3,352 cf Provided Storage Volume = 3,352 cf Allowable 100-Year Peak Release = 0.61 cfs Actual 100-Year Peak Release = 0.61 cfs 100-year, 24-Hour Storm at Overflow = 1 .08 cfs B. Stormwater Detention Pond System Given the limitations of the site grades, the detention pond for the project has been designed with a 3.6-foot ± active storage depth. The water quality storage depth is 3.5 feet. The pond outfall will be into an existing roadside catchbasin approximately 25 feet southwest of the pond with an invert elevation of 10.50. The detention pond has been designed to restrict developed outflow from the project basin based on the City of Renton criteria. This is accomplished using a three-orifice system on a standard FROP-T riser section. The pond sizing and design accounts for the increase in impervious area in Basin C: Qallow = QBpre — �QCpost — QCpre). Peak Release Summary Table � `'�` � ' � ` Predev. Basin B �eV. 8asin c Predev. Bas�� C �eV. Basin C,Allowed Q z Y� 0.37 cfs 0.19 cfs 0.14 cfs 0.32 cfs Q ,o n 0.83 cfs 0.30 cfs 0.24 cfs 0.77 cfs Q ,00 Y� 1 .42 cfs 0.43 cfs 0.37 cfs 1 .36 cfs � � The pond control structure riser is designed to pass the 100-year peak runoff for the developed conditions. A Type II-48" manhole with a "birdcage" trash rack has been provided for emergency overflow conditions. Analytical details (i.e. elevations, orifice diameters, detention volume, release rates etc.) are provided in the WATERWORKS output data sheets provided in Appendix A Custom Stage Storage Data Table Elevation Area (sf) 10.65 2,747 (bottom of pond) 11.00 2,888 12.00 3,366 13.00 3,879 14.00 4,426 15.00 5,008 16.00 5,624 17.00 6,275 - � Detention pond peak volume & outflow Storage Volume = 12,688 cf Provided Storage Volume = 12,930 cf Allowable 100-Year Peak Release = 1 .36 cfs Actual 100-Year Peak Release = 1 .36 cfs 100-year, 24-Hour Storm at Overflow = 3.12 cfs C. Water Quality System The water quality volume was calculated based on the water quality design storm per City of Renton Standards. This volume of runoff is determined from the tributary sub- basin proposed developed conditions using a water quality design storm event having a precipitation equal to one-third of the two-year, 24-hour precipitation. Basin A Dead Storage Volume Required = 2,178 CF Dead Storage Volume Provided = 3,625 CF Dead Storage will be provided under the live storage depth in the combination detention/wet vault. Basin B Dead Storage Volume Required = 5,663 CF ,% Dead Storage Volume Provided = 6,280 CF � '�� ��� !Jr,,� l -- �t �� , � Dead storage will be provided under the live storage depth in the combination detention/wet pond. ' � � �� +� �� (. �� j�l ,� i� � � 1�t11 � - - � � 7 �r 100� 0 100' � _ -- ?�- �ti�---� t SCALE: 1~ - �oo� , `'° '! ' , _M— — — — -- — "WETLAND BUFF R � �� � �' � � ' '��� `p �I � i � � � --� AREA=1.25 AC� ' �� � t � I , � \\\\ 4�� � � � \ \ \\\� � �� '�� � _ -� �� � � �. � �� / al�� � (� � � II 1 \\ \'1 \ � _� _A� � � .�� \� f I �I � 1� �� I AS/ 1 � -- -- - -- � - t��= �, �� �' I ��`�� 'UNDETA/NED. � — � � --- �I \ j -- �°— -- — : ,�\``� ;AREA, ----- - ------Z---- -� - -, � / ,p- � � i ---r---- -------�u=--�---------1- -----�-�__ � � � i 1 i��--.�, �% \ r � ' ------ \-------------, f Jl� ' I , 1 `� B �N B � ���;, ( i � '' � 1 -, AS + � ��.��/ � i� � �' �� r� �,� � �l � � ' �� � rr-ii� � � � � � a � � �■ � �,4 // ,� -� �`� '� ` r�I I� I II ; I � �� ( 1 �� � I �\� , � BASIN � f _ j.' � � --�— -- � � [ � � � � I 1 � 1 — ' � J/ / -, / ' � � �� PROPO�E� � �I ` � i � � . c , � / l-- �) POND � � �� ( . _ ..' ` � � J, -.�-,, L� V � I f � J / - � / � / � I � _ � � � � � � � ` � � I � — -e��- ��'� r �, � , — - PROPOSED " - � _ - - - � � �\ 1 Il I � _ DETEN77 ET _ .- - ��� _ `'� � � � ��� l _u �~` � ` �~� t ` _] �^ \ �i � Y 1 \ `�� `4 _ TC = 77ME OF CONCENTRA TION TC BASIN A = 5.00 M/N. ', � j � TC BAS/N B = 5.00 MlN. �� TC BAS/N C = 9.51 MIN. - SITE BASIN A BASlN B BASIN C TOTAL 321 987 SF 7.39 AC 61 472 SF 1.41 AC 233 840 SF 5.37 AC 26 675 SF 0.61 AC PREDEVELOPED IMPER V10US 9,000 SF 0.2� A C 0 SF 0 SF 0 SF D SF 9,000 SF 0.21 A C PER 1/IOUS 12,987 SF 7.18 AC 61,472 SF 1.41 AC 233,840 SF 5.37 AC 17,675 SF 0.40 AC DEI/ELOPED IMPER l/IOUS 215,9,35 SF 4.97 AC 52,559 SF 1.21 AC 146,093 SF 3.36 AC 17,283 SF 0.40 AC PERVJOUS 106,052 SF 2.42 AC 8,913 SF 0.20 AC 87,747 SF 2.O1 AC 9,392 SF 0.21 AC � TREECE COMPANY EN041EERIHO AND DEVEtAPYEI(T CONSULTANTS 330!M Aw.Sw11�.SJM T00 107u.u0.�lSNK'p1 9E053 rwrt .n enav� nx us en-rH ; CITY OF RENTON � DSPARTI[SNT OT PVHLIC FORX9 0 � PAClFIC C�ULF PROPERTIE! � DEVELOPED CONDITIONt MAP � aa,c�m ani am./+Noo ru Muc ca�[» k yu P ,� ._ __.. . _ d�L[7�Y t47. �p I'• fOC /�0 sa� nr s W VI. CONVEYANCE SYSTEM ANALYSIS and DESIGN An analysis of the proposed conveyance system shall be performed in this section. Given the simplicity and minimal conveyance components the system capacity was checked utilizing the last leg of the system, the total site runoff, and minimum slope as detailed in the following computer data sheets. The design flow was calculated using SBUH, based on the 100 year, 24 hour storm event. The 100 year developed flow for the detention vault and pond at overflow is 1 .08 cfs and 3.12 cfs, respectively. Although, the capacity of.�2" CPEP at 0.50% is 2.34 CFS, two 12" pipe systems (west and east of the proposed warehouse site) will convey the developed flow to the detention pond. The outfall from the pond is a 15" CPEP at 0.50% with a capacity of 4.95 cfs. � � � � — - �� o i 8 CPEP @ 0.50/o Worksheet for Circular Channel Project Description I'� Project File d:\haestadlfmwlproject1.fm2 I, Worksheet Pacific Gulf Warehouse ' Flow Element Circular Channel ', Method Manning's Formula ,I Solve For Discharge ', Input Data ', Mannings Coefficient 0.012 � Channel Slope 0.005000 ft/ft ' Depth 0.67 ft Diameter 8.00 in Results Discharge 0.93 cfs Flow Area 0.35 ft2 Wetted Perimeter 2.09 ft Top Width 0.00 ft Critical Depth 0.46 ft Percent Full 100.00 Critical Slope 0.007573 ft/ft Veloc�ty 2.65 ft/s Velocity Nead 0.11 ft Specific Energy FULL ft Froude Number FULI Maximum Discharge 1.00 cfs Full Flow Capacity 0.93 cfs Full F1ow Slope 0.005000 ft/ft pq��q�pp FlowMaster v5.15 0723:41 AM Haestad Methods,Inc. 37 Brookside Road Waterbury,CT 06708 (203)755-1666 Page 1 of 1 1� 12" CPEP @ 0.50% Worksheet for Circular Channel Project Description Project File d:lhaestadlfmwlprojectl.fm2 Worksheet Pacific Gulf Warehouse Fiow Element Circular Channel Method Manning's Formula Solve For Discharge Input Data Mannings Coefficient 0.012 Channel Slope 0.005000 ft/ft Depth 1.00 ft Diameter 12.00 in Results Discharge 2.73 cfs Flow Area 0.79 ft2 Wetted Perimeter 3.14 ft Top Width 0.00 ft Critical Depth 0.71 ft Percent Full 100.00 Critical Slope 0.006918 ft!ft Velocity 3.47 ftls Velocity Head 0.19 ft Specific Energy FULL ft Froude Number FULL Maximum Discharge 2.94 cfs Full Flow Capac'rty 2.73 cfs Fu11 Flow Stope 0.005000 ft/ft 04J14J00 FlowMaster v5.15 0721:47 AM Haestad Methods,Inc. 37 Brookside Road Waterbury,CT 06708 (203)755-1666 Page 1 of 1 ;� ; � 15" CPEP @ 0.50% Worksheet for Circular Channel Project Description Project File d:lhaestadlfmwlprojectl.fm2 Worksheet Pacific Gulf Warehouse Flow Element Circular Channel Method Manning's Formula Solve For Discharge Input Data Mannings Coefficient 0.012 Channel Slope 0.005000 ft/ft Depth 1.25 ft Diameter 15.00 in Results Discharge 4.95 cfs Flow Area 1.23 ft2 Wetted Perimeter 3.93 ft Top Width 0.33e-7 ft Critical Depth 0.90 ft Percent Full 100.00 Critical Slope 0.006598 ftlft Velocity 4.03 ft/s Velocity Head 0.25 ft Specific Energy 1.50 ft Froude Number 0.12e-3 Maximum Discharge 5.32 cfs Full Flow Capacity 4.95 cfs Full Flow Slope 0.005000 ft!ft Flow is subcrifical. 04114J00 FlowMaster v5.15 0720:48 AM Haestad Methods,Inc. 37 Brookside Road Waterbury,CT 06708 (203)756-1666 Page 1 of 1 ��; i I I �i VII. SPECIAL REPORTS and STUDIES i Past reports that have been prepared in support of the Pacific Gulf Warehouse Project � include the following: , • Pacific Gulf Warehouse: Preliminary Drainage Report; Peterson Consulting j Engineers, August 7, 1998 I • Geotechnical Report; Terra Associates, Inc. June 9, 1999 ' VIII. BASIN AND COMMUNITY PLANNING AREAS I The project site is located within the Black River Sub-basin of the Cedar River , Drainage Basin and within the City of Renton planning area. X. OTHER PERMITS Structural permit for the project's on-site detention vault. Utility permits from the City of Renton Water & Sewer Department. IX. EROSION/SEDIMENTATION CONTROL DESIGN To develop the project site, several Best Management Practices (BMP's) will be implemented. Other temporary erosion and sediment control may occur during the duration of the project depending on weather conditions, clearing operations, and excavation and fill placement. The detention pond are will be used during the interim as a sediment trapping device. Specific TESC measures to be implemented include the following: Filter fabric fencing will be constructed along the west and north side of the site. Rock construction entrance will be constructed at the south entrance to the project. Temporary interceptor ditches will be constructed aiong the west and north side of the project site and routed to the sediment pond. The ditches will be filled and seeded upon project completion to stabilize the surface soil. Sediment pond will be the primary mode of removing any sediment from the runoff prior to release to the downstream system. Pond sizing was based on the 10 year, 24 hour storm event for the developed site. The peak release and corresponding pond area for each was determined using the King County SWDM sediment trap sizing equation using a sediment settling velocity of 0.00096 ftls. �, � S 4_� AreaPo�d = FS x (Q,o/VS} where; FS = factor of safety = 2.0 Q,o = 10 year, 24 hour storm event fsee Basin Summary) = 3.32 cfs (total from Basins A, B, and C} VS = settling velocity = 0.00096 ftls APo�d = 2.0(3.32/0.00096} � = 6917 sf Seeding with an appropriated King County approved seed mix will be initiated along all roadway ditches. � � APPEN DIX A HYDROLOGIC ANALYSES ; 4/13/00 8 : 35 : 8 am Peterson Engineering Consulting page 1 Pacific Gulf Detention vault Basin 'A' BASIN SUMMARY BASIN ID : A NAME: 2 yr predev site basin A SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .41 Acres BASEFLaWS : 0 . 00 cfs R.AINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 1 . 95 inches AREA. . : 1 .41 Acres 0 . 00 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 85 . 00 0 . 00 TC . . . . . 19 . 16 min 0 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 120 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0100 PEAK RATE: 0 .16 cfs VOL: 0 . 09 Ac-ft TIME: 480 min BASIN ID: B NAME: 10 yr predev site basin A SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .41 Acres BASEFLOWS : 0 . 00 cfs R.AINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 2 . 85 inches AREA. . : 1 .41 Acres 0 . 00 Acres TIME INTERVAL. . . . : 10 .00 min CN. . . . : 85 . 00 0 . 00 TC. . . . . 19 . 16 min 0 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 120 . 00 ns :0 . 1500 p2yr: 1 . 95 s : 0 . 0100 PEAK R.ATE : 0 .36 cfs VOL: 0 . 17 Ac-ft TIME : 480 min BASIN ID: C NAME: 100 yr predev site basin A SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .41 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 3 . 85 inches AREA. . : 1 .41 Acres 0 . 00 Acres TIME INTERVAL. . . . : 10 .00 min CN. . . . : 85 . 00 0 . 00 TC. . . . . 19 . 16 min 0 .00 min ABSTR.ACTION COEFF: 0 .20 TcReach - Sheet L: 120 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0100 PEAK R.ATE: 0 . 61 cfs VOL: 0 .27 Ac-ft TIME: 480 min BASIN ID: D NAME: 2 yr postdev site basin A SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .41 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 1 . 95 inches AREA. . : 0 . 20 Acres 1 . 21 Acres TIME INTERVAL. . . . : 10 .00 min CN. . . . : 86 . 00 98 . 00 TC . . . . . 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 PEAK RATE : 0 .51 cfs VOL: 0 . 19 Ac-ft TIME : 480 min 4/13/00 8 : 35 : 8 am Peterson Engineering Consulting page 2 Pacific Gulf Detention vault Basin 'A' --------------------------------------------------------------------- --------------------------------------------------------------------- BASIN SUMMARY BASIN ID : E NAME : 10 yr postdev site basin A SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .41 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 2 . 85 inches AREA. . : 0 . 20 Acres 1 . 21 Acres TIME INTERVAL. . . . : 10 .00 min CN. . . . : 86 . 00 98 . 00 TC. . . . . 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 120 . 00 ns : 0 . 150d p2yr: 1 . 95 s : 0 . 0001 PEAK RATE : 0 . 78 cfs VOL: 0 .29 Ac-ft TIME : 480 min BASIN ID: F NAME: 100 yr postdev site basin A SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .41 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 3 . 85 inches AREA. . : 0 .20 Acres 1 .21 Acres TIME INTERVAL. . . . : 10 .00 min CN. . . . : 86 . 00 98 . 00 TC. . . . . � 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 120 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0001 PEAK RATE : 1 .08 cfs VOL: 0 .40 Ac-ft TIME : 480 min BASIN ID: G NAME: WQ postdev site basin A SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .41 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 0 . 65 inches AR.EA. . : 0 .20 Acres 1 .21 Acres TIME INTERVAL . . . . : 10 .00 min CN. . . . : 86 . 00 98 . 00 TC. . . . . 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 120 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0001 PEAK RATE : 0 . 13 cfs VOL : 0 . 05 Ac-ft TIME : 480 min 0 � .o �C�.�Jj �C -F�� ���JJ� �� �,�. �2� Q�.D x k��11�-�,r �� �J'.•� � � ' � ;�, �- Z� � B ��- N � ° , .,, . . _.�.._.._- . _.�.� � 5 � �,�. � �% . � . � �, 4/13/00 8 : 35 : 8 am Peterson Engineering Consulting page 3 Pacific Gulf Detention vault Basin 'A' --------------------------------------------------------------------- --------------------------------------------------------------------- STAGE STOR.AGE TABLE RECTANGULAR VAULT ID No . vaultA Description: vault for Basin A Length: 72 . 00 ft . Width: 19 . 00 ft . voids : 1 . 000 STAGB <----STC3AGB----> STnG6 <----STORAG6----� ST1G6 <----STOR�G&----> STAGB �----S�CR�+GB----> (ft) ---cf--- --AC-Ft- (ft) ---Cf--- --AC-Ft- (ft{ ---Cf--- --AC-Ft- (ft) ---Cf--- --AC-Ft- -------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------- 11.95 O.00DO 0.0000 12.90 1300 O.Oi98 13.90 2668 0.0612 14,90 4036 0.0926 12.00 68.400 0.0016 13.D0 1436 0.0330 14.00 2804 0.0644 15,00 4112 0.0958 12.?0 205.20 0.0047 13.10 1573 0.0361 14.10 2941 0.0615 15.10 4309 0.0989 12,20 342.00 0.0079 13.20 1110 0.0393 14.20 3078 0.0707 15.20 4446 0.1021 12.30 478.80 0.0110 13,30 1541 0.0424 14.30 3215 0.0738 15.30 4583 0.1052 12.40 615.60 0.0141 13,4D 1984 0.0455 14.40 3352 0.0769 15.90 472D 0.1083 12.50 752.40 0,0113 13.50 2120 0.0481 14,50 3488 0.0801 15.50 4856 0.111� 12,60 889.20 0.0204 13.60 2257 0.0518 14,60 3625 0.0832 15.60 4993 0.1146 12,70 1026 0.0236 13,7D 2394 0.0�50 14,70 3762 0.0864 15.70 5130 0.117E 12,9� 1163 0.0267 13.9D 25?1 0.0��1 i4.60 3899 0.0895 15.E0 5267 0.12C9 � 4/13/00 8 : 35 : 8 am Peterson Engineering Consulting page 4 I Pacific Gulf Detention vault Basin 'A' --------------------------------------------------------------------- --------------------------------------------------------------------- STAGE DISCHARGE TABLE MULTIPLE ORIFICE ID No. orifA I Description: vault flow restrictor Outlet Elev: 11 . 95 Elev: 9 . 95 ft Orifice Diameter : 2 . 3027 in. Elev: 13 . 35 ft Orifice 2 Diameter : 3 . 0234 in. Elev: 13 . 85 ft Orifice 3 Diameter: 2 . 5664 in. STAGB <--DISCHARG�---> STAGB <--DISCEARGB---> STAG6 <--DISCHA3GB---> STAGB <--DISC�ARGB---> (ft1 ---cfs-- ------- (ft) ---cfs-- ------- Ift) ---cfs-- ------- (ft) ---cfs-- ------- -------------------------------------------------------------------------------------------------------- 11.95 0.0000 12,60 0.1160 13.30 Q.1672 14.00 0.4752 12,D0 0.0322 12,70 0.1246 13.40 0.2287 14.10 0,5152 12,10 0.0557 12,80 0.1327 13,50 0.2152 14,20 0.5503 12,20 0.0719 12.90 0.1403 13.60 0.3069 14.30 0.5823 12.30 0.0851 13.00 0.1474 13.70 0.3311 14.40 0.6120 12,40 0.0965 13.10 D,1543 13.80 0.3b21 14,50 0.6399 12.50 0.1057 13.20 0,1609 13.40 0.4249 �..� � .� '� � 4/13/00 8 : 35 : 8 am Peterson Engineering Consulting page 5 Pacific Gulf Detention vault Basin 'A' STAGE DISCHARGE TABLE RISER DISCHARGE ID No. riserA Description: control for vault A Riser Diameter (in) : 18 . 00 elev: 11 . 75 ft Weir Coefficient . . . : 9 .739 height : 15 . 00 ft Orif Coefficient . . . : 3 . 782 increm: 0 . 10 ft STAGB <--DISCHARGB---> STAG� <--DISCHARGB---> STAGB c--DISCHARG3---> STAG3 <--DISCHARG6---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ftJ ---cfs-- ------- {ft) ---cfs-- ------- -------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------- ll.75 0,0000 12,60 7.8454 13.50 11.257 14.40 13.852 11.80 6.1633 12.10 8.2940 13.60 11.574 14.50 14.1i1 11.50 0.8467 12.90 8.7196 13.70 11.883 14.60 14.366 12.00 1.8261 12.90 9.1254 13.80 12,184 14.70 14.616 12.10 3.0249 13.00 9,5139 13.9Q 12.477 14.80 14.861 12.20 4.4099 13,1D 9.6871 14.00 12.764 14.90 15.103 12,30 5.9567 13.20 10.247 14,10 13.045 15,00 1�,341 12.�0 6.8606 13,30 10.594 14.20 13.3?9 12.50 7,3694 13.4C 16.931 14.30 13.539 4/13/00 8 : 35 : 9 am Peterson Engineering Consulting page 6' Pacific Gulf Detention vault Basin 'A' --------------------------------------------------------------------- --------------------------------------------------------------------- LEVEL POOL TABLE SUMMARY MATCH IIiFLOW -STO- -DIS- c-FBAK-> STORAG6 <--------D6SCRIPTION---------> (Cfs) (Cfsl --id- --id- <-STAG6> id VOL �Cf► ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- 2yr .......... ................ 0.16 0.51 vaultA crifA 13.20 1 1711,66 cf l0yr . ........................ 0.36 0.78 vaultA crifA 13.80 2 2526.68 cf 100yr ... ..................... 0.6? 1.08 vaultA orifA 14.40 3 3351.61 cf ; 4/13/00 9 : 20 : 8 am Peterson Engineering Consulting page 1 Pacific Gulf Properties Detention Pond Basins B & C (bypass) --------------------------------------------------------------------- --------------------------------------------------------------------- BASIN SUMMARY BASIN ID: G NAME: 2 yr predev site basin C SBUH METHODOLOGY • TOTAL AREA. . . . . . . : 0 . 61 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 1 . 95 inches AR.EA. . : 0 .40 Acres 0 . 21 Acres TIME INTERVAL. . . . : 10 .00 min CN. . . . : 85 . 00 98 . 00 TC. . . . . 9 .51 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 50 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0100 PEAK RATE: 0 . 14 cfs VOL: 0 . 06 Ac-ft TIME : 480 min BASIN ID: H NAME : 10 yr predev site basin C SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 61 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 2 . 85 inches AREA. . : 0 .40 Acres 0 .21 Acres TIME INTERVAL. . . . : 10 .00 min CN. . . . : 85 . 00 98 . a0 TC. . . . . 9 .51 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 50 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0100 PEAK RATE : 0 .24 cfs VOL: 0 . 09 Ac-ft TIME : 480 min BASIN ID: I NAME: 100 yr predev site basin C SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 61 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 3 . 85 inches AREA. . : 0 .40 Acres 0 .21 Acres TIME INTERVAL. . . . : 10 .00 min CN. . . . : 85 .00 98 . 00 TC. . . . . 9 .51 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 50 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0100 , PEAK RATE : 0 .37 cfs VOL: 0 . 14 Ac-ft TIME : 480 min BASIN ID: J NAME: 2 yr postdev site basin C � SBUH METHODOLOGY �, TOTAL AREA. . . . . . . : 0 . 61 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 1 . 95 inches AREA. . : 0 .21 Acres 0 .40 Acres TIME INTERVAL. . . . : 10 .00 min CN. . . . : 86 .00 98 . 00 TC. . . . . 9 .51 min 5 .00 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 50 .00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0001 PEAK RATE: 0 . 19 cfs VOL: 0 . 07 Ac-ft TIME : 480 min � 4/13/00 9 :20 : 8 am Peterson Engineering Consulting page 2 Pacific Gulf Properties Detention Pond Basins B & C (bypass) --------------------------------------------------------------------- --------------------------------------------------------------------- BASIN SUMMARY BASIN ID: K NAME : 10 yr postdev site basin C SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 .61 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 2 .85 inches AREA. . : 0 . 21 Acres 0 .40 Acres TIME INTERVAL. . . . : 10 .00 min CN. . . . : 86 . 00 98 . 00 TC. . . . . 9 .51 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 50 .00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0100 PEAK RATE : 0 .30 cfs VOL: 0 . 11 Ac-ft TIME : 480 min BASIN ID: L NAME: 100 yr postdev site basin C SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 61 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 3 . 85 inches AREA. . : 0 .21 Acres 0 .40 Acres TIME INTERVAL. . . . : 10 .00 min CN. . . . : 86 . 00 98 . 00 TC. . . . . 9 .51 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 50 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0001 PEAK RATE : 0 .43 cfs VOL: 0 . 16 Ac-ft TIME : 480 min BASIN ID: M NAME: 2 yr predev site basin B SBUH METHODOLOGY TOTAL AREA. . . . . . . : 4 . 12 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 1 .95 inches AREA. . : 4 .12 Acres 0 . 00 Acres TIME INTERVAL. . . . : 10 .d0 min CN. . . . : 85 . 00 0 . 00 TC. . . . . 39 . 88 min 0 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 300 .00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0100 PEAK RATE : 0 .37 cfs VOL: 0 . 26 Ac-ft TIME: 490 min BASIN ID: N NAME : 10 yr predev site basin B SBUH METHODOLOGY TOTAL AREA. . . . . . . : 4 .12 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 2 .85 inches AREA. . : 4 . 12 Acres 0 . 00 Acres TIME INTERVAL . . . . : 10 . 00 min CN. . . . : 85 . 00 0 . 00 TC. . . . . 39 .88 min 0 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0100 PEAK R.ATE : 0 . 83 cfs VOL: 0 .50 Ac-ft TIME : 490 min 4/13/00 9 :20 : 8 am Peterson Engineering Consulting page 3 Pacific Gulf Properties Detention Pond Basins B & C {bypass) BAS IN SUNIMARY � BASIN ID: O NAME: 100 yr predev site basin B SBUH METHODOLOGY TOTAL AREA. . . . . . . : 4 . 12 Acres BASEFLOWS : 0 . 00 cfs � RAINFALL TYPE . . . . : TYPFIA PERV IMP PRECIPITATION. . . . : 3 . 85 inches AREA. . : 4 . 12 Acres 0 . 00 Acres I TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 85 . 00 0 . 00 i TC . . . . . 39 . 88 min 0 . 00 min � ABSTR.ACTION COEFF: 0 .20 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0100 � PEAK RATE : 1 .42 cfs VOL: 0 . 80 Ac-ft TIME : 490 min BASIN ID: P NAME : 2 yr postdev site basin B SBUH METHODOLOGY TOTAL AREA. . . . . . . : 4 . 12 Acres BASEFLOWS : 0 . 00 cfs I RAINFALL TYPE . . . . : TYPElA PERV IMP I PRECIPITATION. . . . : 1 .95 inches AREA. . : 0 . 76 Acres 3 . 36 Acres � TIME INTERVAL . . . . : 10 .00 min CN. . . . : 86 . 00 98 . 00 I TC. . . . . 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 50 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0001 I PEAK RATE : 1 .45 cfs VOL: 0 . 53 Ac-ft TIME: 480 min BASIN ID: Q NAME: 10 yr postdev site basin B - SBUH METHODOLOGY TOTAL AREA. . . . . . . : 4 . 12 Acres BASEFLOWS : 0 .00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 2 . 85 inches AREA. . : 0 . 76 Acres 3 . 36 Acres TIME INTERVAL . . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC. . . . . 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 50 .00 ns : 0 . 1500 p2yr: 1 .95 s : 0 .0001 PEAK R.ATE: 2 .24 cfs VOL: 0 . 83 Ac-ft TIME : 480 min BASIN ID: R NAME: 100 yr postdev site basin B SBUH METHODOLOGY TOTAL AREA. . . . . . . : 4 . 12 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 3 . 85 inches AREA. . : 0 . 76 Acres 3 . 36 Acres TIME INTERVAL. . . . : 10 .00 min CN. . . . : 86 . 00 98 . 00 TC. . . . . 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 50 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0001 PEAK RATE : 3 . 12 cfs VOL: 1 . 17 Ac-ft TIME : 480 min 4/13/00 9 :20 : 8 am Peterson Engineering Consulting page 4 Pacific Gulf Properties Detention Pond Basins B & C (bypass) --------------------------------------------------------------------- --------------------------------------------------------------------- BASIN SUMMARY BASIN ID: S NAME : WQ 1/3 2 yr precip for basin B SBUH METHODOLOGY TOTAL AREA. . . . . . . : 4 . 12 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 0 . 65 inches AREA. . : 0 . 76 Acres 3 . 36 Acres TIME INTERVAL . . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC. . . . . 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 50 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0001 PEAK R.ATE: 0 .36 cfs VOL: 0 . 13 Ac-ft TIME : 480 min I ,i i _ o ,t3 1��-� ��l-356Q� I �o�- � � � ��Q �� �'�� I �� �lo�3 C� �� __.. ��.,._��_�--i- 4/13/00 9 : 20 : 8 am Peterson Engineering Consulting page 5 Pacific Gulf Properties Detention Pond Basins B & C (bypass) --------------------------------------------------------------------- --------------------------------------------------------------------- STORAGE STRUCTURE LIST STORAGE LIST ID No. pond Description: stage storage for pond � � ,r , ; � : � � i � 11 � _+ - 1 � , ._.� � r I __1 4/13/00 9 :20 :8 am Peterson Engineering Consulting page 6 Pacific Gulf Properties Detention Pond Basins B & C (bypass) STAGE STOR.AGE TABLE CUSTOM STOR.AGE ID No. pond Description: stage storage for pond , STAGB <----STORAGB----> STAG6 <----STORAGB----> STAGB c----STORAGB----> STA6B c----STORAG�----� (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ftJ ---cf--= --AC-Ft- -------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------- 10.65 0.0000 O.00CO 12.30 5200 0.1194 14.00 11888 0.2729 15.70 20326 0.4666 � 10.10 140.88 O.DD32 12.40 5562 0.1277 14.10 12360 0.2831 15.80 20858 0.4788 10.80 422.63 0.0097 12.50 5924 0.1360 14.20 12832 0.2946 15.90 21390 0.4910 10.90 704.38 0.0162 12,60 6287 0,1443 14.30 13303 0.3054 16.00 21921 0,5032 11.00 986.13 0.0226 12,10 6b49 0.1526 14.40 13775 0.3162 16.10 22516 C.5169 11.10 1299 0.0298 12,8D 7011 0.1610 14.50 1424T 0.3271 16.20 23111 0.5306 1i.20 1612 0.0370 12.90 7313 0,1693 14.60 14718 0.3379 16.30 23706 0.5442 11.30 1924 0,0442 13.00 7736 0,1776 14.70 15190 0.3487 16.40 24301 D.5579 11.40 2231 0.6514 13.10 8151 O,1B71 14.80 15662 0.3595 1b,50 24896 0.5715 11.50 25§0 0.6585 13.20 8566 0.1961 14.90 16133 0.3704 16,60 25491 0.5852 11.60 2862 0.0657 13.30 8981 0.2062 15.00 16605 0.3812 16.70 26686 0.5988 11.10 3175 0.0729 13.40 9391 0,2157 15.10 17137 0.3934 16.80 2EE81 0.6125 11.80 3488 0.0801 13.50 9812 0.2252 15.20 1766� 0.4056 16.90 27276 0.6262 11.90 3800 0,0812 13.b0 16227 0.2348 15.30 18200 0.4118 11,00 27871 0.6398 _2.00 4113 0.0944 13.70 10642 0.2443 15,46 18732 0,93C0 :2.10 4475 0,1021 13.8C 11058 0.2538 15.50 19263 0.4�22 12.?G 4338 0.1111 :3.9� 114�3 0.2634 '_�,6C 1979� 0,':,« 4/13/00 9 : 20 : 8 am Peterson Engineering Consulting page 7 Pacific Gulf Properties Detention Pond Basins B & C (bypass) --------------------------------------------------------------------- --------------------------------------------------------------------- DISCHARGE STRUCTURE LIST MULTIPLE ORIFICE ID No. pondorif Description: pond flow restrictor �utlet Elev: 10 .65 Elev: 8 . 65 ft Orifice Diameter: 2 . 8447 in. Elev: 12 . 85 ft Orifice 2 Diameter: 4 . 3359 in. Elev: 13 . 55 ft Orifice 3 Diameter: 4 . 1250 in. ; n � . . ; "b � � , ,.� � ,' � -, ' ,: . � � ��) � � : i ' ; ' ; � � • � � I . II ' � t � � .__, ., # ' _ 4/13/00 9 : 20 : 8 am Peterson Engineering Consulting page 8 Pacific Gulf Properties Detention Pond Basins B & C (bypass) --------------------------------------------------------------------- --------------------------------------------------------------------- STAGE DISCHARGE TABLE MULTIPLE ORIFICE ID No. pondorif Description: pond flow restrictor Outlet Elev: 10 . 65 Elev: 8 . 65 ft Orifice Diameter: 2 . 8447 in. Elev: 12 . 85 ft Orifice 2 Diameter: 4 .3359 in. Elev: 13 . 55 ft Orifice 3 Diameter: 4 . 1250 in. STAGB <--DISCHARGB---> STAGB <--DISCHARGB---> STAGB <--DISCHARGB---� STAG6 <--DISCHARGB---> (ftJ ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- -------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------- 10.65 0,0000 11,60 0.2140 12.60 0.3067 13.60 0.9223 10.70 0,0491 11.10 0,2250 12.70 0.3144 13.70 1.0327 10.80 0.0851 11.80 0.2355 12.80 0.3220 13.80 1.1179 10.90 0.1098 11.9D 0.2455 12.90 0.4435 13.90 1.1919 11.00 0.1299 12,OD 0.2SS2 13,00 0.5342 14.00 1.2588 11.10 0,1413 12.10 0.2644 13.10 0.5988 14.10 1.3207 11.20 0,1629 12.20 0.2734 13.20 0.6525 14.20 1.3788 11.30 0,1771 12.30 0.2821 13.30 0.6997 14.30 1.4338 11.40 0.1902 12.46 0,2905 13.40 0.7425 14.40 l.cg62 11.50 0.2025 12.§0 0,2987 13.50 0.7821 14.50 1.5363 I ' 4/13/00 9 : 21 : 30 am Peterson Engineering Consulting page 9 Pacific Gulf Properties Detention Pond Basins B & C (bypass) --------------------------------------------------------------------- --------------------------------------------------------------------- LEVEL POOL TABLE SUMMARY MATCH INFLCW -STO- -DIS- <-PBAK-> STORAGB <--------DBSCRIPTION---------> (cfs) (cfs� --id- --id- <-STAG&� id VOL (Cf) 2yr ..... ......... . ........... 0.32 1,45 pond pondorif 12.77 21 6914.38 cf 1Dyr ............. . ........... 0,77 2,24 pond pondorif 13.47 21 9692.85 cf , 1DOyr ........... . . ........... 1.36 3.12 pond pondorif 14.17 21 12687.13 cf t _,� ; � � II ' � . 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'� , , �� � - �,.�r � . 1 � � , ����' �� � `ir ; • -���i�i�+'��" ,��a�111►�r ��: �,�,,, ` � • e��!=:'�i�� ��/� �� f � 1 O ` ' � �'a�',!��`,� r � �� — � � - ,�� - , ��.a�ai 1R �. �� � ��__l.��e,��� � 1`r.� .i � ��� � __���w��� �� �� � � ^1 ����• �i�,�'��- t I � -� - ��► � � , ._ : �� , . �� � �, . .� �� �� � �. _;.;:�►-.. /., t/� � �:� , �� � �y���� � .,��� � . � , , ��.'.'����� , Z��'��i � ; „� •���� . �,�����L ,.�/r.,�����.,� ��.�� / � i�Q�� �►" �/\���,.��•��`.�'ti''��"'�' _ ., 11 �t1 ~�`� � •����'7i�._T������.w_ . . . 1 �� `�'�,�'��'��� 1 `� • —� � ��� �t��� �-S� � -- 1 . . ��' � ��� ;. �� � �;.��� ���.�.'��� � � � � �►, �� � _ � �� �' E: . � � �� �z � ti, , V ;/'� � • � � ��� � �� � � s��� ���;,,,� � -E __ � �. ��,��;�:�,�,,,,� ,�I���,�1�`�� -. � 1l� ¢,�,, ,,� �, � `���, - �flI�A �►,1� �'�i ��-�►� � �-�� �������\ , �~�. 1^�-��r�•; �'! . �_ �'� :� �#� �. • � � �� '�w��lr . k�� '!�1 �, .,,` �� [�i �� �.� � •� �l � �i I� - ��� �� � �� �wai f � • ���/ - � � � �I � �.�� � �,1�..c�w� .� _ . � 1 �� � �,`�� � � + , G- �,►�i �( „ � �� �� -��� �., '���� `- .�.���l�� � t•�F'-� � � G���' � ���� , 1�.���� i�i►�`ii�l�1� `t� . � � _ � � . . � ��� � � L �� t� ��� ,� ���w� .. F _ � ..,.s / �AIM/��%A1 � a�#II -- -- 1 ► - �� .. �� � �,�1'" ��► �l.��. '� ��� �� �,....�:����� ! � - ' � , �� I � ' � �I' � ,o � �. .� .����� ,��' � •.' . !�Fi �r.e `ti t� +�� . , � • , �� � ��` d� ��� � � . �� � � y ' ' . � . °. . �� '� � � , . .� .I./�� �a • • ��/�'���:��' � , . , . . . . . . . ��,��� j�M'i� • . � � , . • . �� . ' ' `���i�h� • � . . . � ./, . . : i . • —� ------- . , � � .. �.� .� KING COUNTY, WASHINGTON, SURFACE WATER DESIGN I�IANUAL TABLF 3.5.2I3 SCS �VESTERN VVASHInGTON RUNOFF CURVE NUMBERS .- � SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS (Published by SCS in 1982) Runoff curv� numbers for selected agricultural, suburban and urt�an land use for Type 1A rain(ali distribution, 24-hour storm duration. CURVE NUMBERS BY HYDROLOGIC S GROUP LAND USE DESCRIPTION A B C D Cultivated land(t): winter condition 86 91 94 95 Mountain open areas: low growing brush and grasslands 74 R2 89 92 Meadow or pasture: 65 78 85 89 Wood or forest land: undisturbed or older second growth 42 64 76 81 Wood or forest land: young second growth or brush 55 72 81 86 � Orchard: with cover crop 81 88 92 94 Open spaces, lawns, parks, golf courses, cemeteries, landscaping. good condition: grass cover on 75% or more of the area 68 80 � 90 fair condition: grass cover on 50°,b to 75°�6 of the area 7� 85 O 9� , Gravel ro2ds and parking lots 76 85 89 91� Dirt roads and parki�g lots 72 82 87 89 Impervious surfaces, pavement, roofs, eic. 9R 98 QB 98. -- Open water bodies: lakes, wetlands, ponds, etc. 100 100 i00 100 Single Family Res'�dential (2) Owelfing Unit/Gross Acre 96 Impervious (3) 1.0 DU/GA 15 Separate curve number 1.5 DU/GA 20 shall be selected 2.0 DU/GA 25 (or pervious and 2.5 DU/GA 30 impervious portion 3.0 DU/GA 34 of the site or basin 3.5 DU/GA 38 4.0 DU/GA 42 4.5 DU/GA 46 5.0 DU/GA 48 5.5 DU/GA 50 6.0 DU/GA 52 6.5 DU/GA 54 7.0 DU/GA 56 Planned unit developments, °�6 impervious condominiums, apartments, must be computed commercial business and industrial areas. (t) For a more detailed description of agricultural land use curve numbers refer to National Engineering Handbook, Section 4, Hydrology, Chapter 9, August 1972. . (2) Assumes roof and driveway runoff is directed into street/storm system. (3) The remaining pervious areas (lawn) are considered to be in good condi;ion for these curve numbers. � 3.5.2-3 11/92 x�-�`, �l.%�n t��Jt '��- :�� � '� ,.� � ` .,jd�-, ' r: �„�p` r ,� � � r , � ��� � �. z� �J�— . , •- t } t , � . . � �.' , J j..� ^ , , ,.�,. � � � ._��__.. I BLACK RIVER BASW ° � � ����- •; ` e1�k ¢ ,".e •� 1 r` � ~ . _ � � f�, � � � � � ,e� \. i i, � �`� , # ' � .��• Basin Boundary - ` ` � ` � �: � , ..� _ -� t. � . � < � `\ .� � f \ T Subcatchment Boundary � �� �_ �� 3 0 � � '"I �:�-r ' �, ��� O Collection Point :, — �_ _, '�F�: x �°�'I { 4` :- of�� ., ' ,. = ; _ �;- �,s- 4, � � ��� Stream _'i_ � , _ 1 � ..�+- o ,�. ,;,�\_,,. _ I _� �`T ,`,", y • ' C+C� ��,� 000s Tributary Number i�kwila •� , � ( `'`<, � y�\ _.�„r.. , 'T.: ��a.,,'�� ��.�, �_ •0301 Proposed Project � � � ! ":�c - '` 'F-- � ' � .5„������ 1�� I , 0006:� '`' �1� ;.� ,,,;,f . ,'�i .I 1�}..': :c���«< { _� ;' � . 7� , _ �` � N —T--� _ _ G � 4�_ -I � I r'�`���f :�' 1_ � - j I; = �� �� i � , '�. �i ti �_ �y � . _ - - � �+ � � _ J �OO�h � � ;;i i i\ I _ � { � ti 1� �7� 0 � i _f� �` _ - _1 ; '\ �nuw _ .� I � I . . .� ''1 , „ o ,�.� � l �; � ' �,,;�: ; 2- 4�. � '--{ -�` ��-',,: `� � , r � o .�� . . . � , ,..<«.0 , ; ,. . � o _ Nb^GF � � \ � ;- , ` . . 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(/F� r ' 0 M C � "`�., � I ` ,urt1' ' i I ��� ` �fr7-r{�= t,..` '';: � '� °O � 15'. '" `� _ ,. ` _ � 1� �` ` -+ •.i '-� '��I Q �1 � �•''1 I __ i - �' o \\. � 1 I !!-- - �OS =' ' .1' �� } � _ --- /' ��� '�T. `,��.... �r) / 1:.,�, ,_ . �`I, � �1�-^O ,���`, ��y . '� [ ,/ � • , ,,..� . � " ,:�. �',�� ,-¢;,_, �,�1 1 , � :\ t` ,,e �- -� �, � . . ,7�'_ �, : � � :.; - � �:,.�'�1 S� . __ o, ,�, �� I f_ i ,.,;� 'G� .��.5`y,�.� � �1 '\ �� . F-,. � l �" oN ' I , :., ` .�j ?. � �� ' �--- �'j' I I:��1.,�, i I� , .. . , - _. . � ' �.` � 1 l. ._ y - I �/,�'� . . � . • r_� I. : ' . • I , .. � . . � _ i� , I'I' � .. 1` , . . . „ ' . �\ .. I �1� , .,. : " ._,_ �' ,i . 7 ' I �' � � . ' " ' i �:. '� ... . �� � ... , , tl� _ .'.... . ._ ". '_ � _ . .�. PETERSON C ONSULTING • September 1, 2000 Mrs. Jan Illian Development Services City of Renton 1055 South Grady Wati Renton, ��'A 980�5 Subject: Pacific Gulf Properties ,. . � tili,� �'l-:rt t£r��'sts 3��� ���tw Q 4���P1;��fi Dear Mrs. 1 I � �: In regards to the suu�ect pro�ect, 1 am responding tu a recent request by iti1r. r�iien lluynn ot th� City of Renton's Surface Water Management Division. The following discussion with attached calculations is intended to revise and supplement the earlier submitted materials. The Technical Information Report(TIR) dated Apri123, 2000 provided an analysis of the existing site of which three drainage basins, or subbasins, were defined: Basin A, B, and C. Given the topography and boundary constraints of the site it was determined that providing detention for Basin C was not feasible. To compensate for the developed drainage in Basin C, the detention pond for Basin B was oversized by an appropriate volume to match the difference between predeveloped and developed conditions in Basin C. This difference was subtracted from the allowable release rate (predeveloped) for Basin B. Consider the oll�owing table that was taken from the TIR: , , � r: .-1 , ,,�, ' _----- � � _ J� .7J_,ls = 5� 'L g� L c Peak Release 5ummary Table `��� �,�z -.�c= ,�z -�7 � . �i+ L � ��� -� o<}�� ��I�r�� iti� � �'>;i Predev. B�B Dev. B�;,,� Predev. �� Dev. �;,,a��� ; Q Z n 0.37 cfs 0.19 cfs 0.14 cfs 0.32 cfs Q lo n 0.83 cfs 0.30 cfs 0.24 cfs 0.77 cfs The above table and basin/detention system analysis as provided in the TIR provides support that the project's peak release requirements from Basin B and C are satisfied. Provisions for storm water quality of Basin C's developed drainage has now been made by routing the developed drainage from Basin C through the detention vault for Basin A. Since the detentic�,n r�a�Lirem .Pnte La..__,. for the total project have�been satisfied the vault was simply increased by the wa�er �° fl� �� i � ; ���a��� F � : i S E P 0 5 2000 � � �ll1L�ING L71V!SiON � �103� L+.,t 1V���ii�crc,�. Bui�. NE S�irE ?(l� • K�r,r..��,�u. 1�ti'�;,�ii��� ��,� 9��n;3 • ;�?5i �;?'-��3,-Y ._�-i-��+�-?��aN;�-ph.�� _ , , Mrs. Jan Illian—City of Renton Page 2 September 1, 2000 � volume (see Supplemental Drainage Calculations: date August 24, 2000). However, to maintain the functionality of the detention vault and its release rate, a flow-through analysis was performed. • The flow-through analysis maintains the established stage-storage relationship from the Level Pool Routing Table while increasing the orifice diameter to compensate for the additional flow of 0.19 cfs and 0.30 cfs during the 2 year and 10 year 24-hour developed storm event (see Developed B,�;�� above). Please refer to the enclosed "Detention Vault Sizing Calculations" for details of the analysis. I am hopeful that the above discussion with the enclosed analysis and revised plans will sufficiently satisfy your needs. If you have any questions, please give me a call at (425) 827-5874. Sincerely, I PETERSON CONSU TING ENGI�VEERS , -�� � _ � � Keith A. Litchfield, P I Ce: Bart 7 i eece, 1'.�., 1 reece c�. L�mpanti Enclosures: Detention Vault Sizing Calculations—Pacific Gulf Properties Revised Civil Engineering Plans (2 sets) - �����`��i���� SEP 0 5 2000 BUIL�ING DI�i�SlO�! . � DETENTION VAULT SIZING CALCULATIONS Revisions to TIR Dated April 13, 2000 Pacific Gulf Warehouse City of Renton File No. LUA99-105,SA-H,ECF Owner/Developer: Pacific Gulf Properties, Inc. 4220 Von Karman Avenue, 2nd Flr Newport Beach, CA 92660-2002 (949) 223-5000 Prepared by: Robert Ludwig, E.I.T. Reviewed by: L 1 Keith A. Litchfield, P.E. ,, � oF �-as,y��, �,� �� .�, �> �, ti�' ��`� a �-r; � � PETERSON � Y `� ONSULTING � ` �� � ,� =�:�-; o �:� f � �,s, �C1 STEg4' �..�' ��5/Z�� 4030 LAKE WASHINGTON BLYD.N E,SUITE ZOO ��Sf ONAL E�`G` � KIRKUND,WASHINGTON 9$O33 EXPIRES 02/10/01 Se tember 1, 2000 � p PCE Job N�. = �� ; SEP C' � 2000 , ' BUIL�I(Vcu �IVISION � Detention Vault Revision , During the final review/revisions of the storm drainage system for the project it was determined that the wet vault storage volume inside the vault would be increased to provide water quality for the northern developed drainage (i.e. Basin C: see earlier TIlZ). Calculations were submitted to support the volume increase under cover of "Supplemental Drainage Calculations". To maintain the functionality of the detention vault and its release rate, a flow-through analysis was performed. The flow-tbrough analysis maintains the established stage-storage relationship from the Level Pool Routing Table while increasing the orifice diameter to compensate for the additional flow of 0.19 cfs and 0.30 cfs during the 2 year and 10 year 24- hour developed storm from Basin C. The calculations that follow are intended to stand-alone and replace earlier sizing calculation for the detention vault. i i G i R����1�.,� �k � SEP 0 5 2000 ,� { Bi1i�DING DIVISION /' : T�� C--��d-1 �1_- -_ __._f������_�� �-��-_ 1P��=`.%z,_s�__�K=__-- �/3��a�__ ---_ _ _ � _ ', . �p e v�, s ;�'r�s �c� F 1a u, �G� �o u.�� ��c <«' s U. G��, ���� o H Au� u �> � ; 2 �/�`� 2Do0• �� I � : ; • k CS�t/ M i1/ov. iqqz �ye �l, �l. 7— I � • I /' i I Q - C� 2 p �1 A = GL.v�'G[. 07� D Y, �R C � ,. r/ c = 0. 6 Z. � �oe�'�';� ; P��o��:�t�a� e; • � � _ r — �Z �'t = ��,GC y a r.�L;c 1�ea �i `y o I � z a Li ` L/ � - �� . � y c�SPc � ��I YGt V I'�� ; � � i: ia � � ; . �,�/I � y ��Z �, � j �• !/! �---�1 I ° �71- C �✓ �. 1 U � � � � � ' /�-ssu � -e G�e� o�s cc.ve �a ;� fa �� e� Q � ex�`s�, �y /e�eLs . 'I � .__ I o �' zw I ' F�o w � � De�e �o�P�-.1 �o��: � �OµS : �Fhv w� A/P�,,,- I�v�+..�;. 1,�.ati�s� � P�,�fo�.t� 7 � BG.s ;,, ga.s ;� B�s;N � A � &� � zU ,� O. slc�s o.l4c�s a• 7oc fs 1�U �, �. 7f�c�S � , 3oc�s 1, o �3c�s ; i � - �i� �� � ,�,� o �' o�,, F ;�Q s : <F�o�, �v�.�, S� D%x�.�.J� , _ � � � o q s-� � ow, „; ;c�e .9 -� 1-e 7 o�t � � 7 n ��f o� ; -� '� C -e = 1 3 .�S.L � z E o�-El� � _ !� .qs.�,� � ' P��fc s -�y.�s o-� s -�o�w, 2 v e�,, �S : � 1=,.��,,., New Ge��L 1�oo L fi��1�e �. � �..�, y- - I 3 ..6 Z � s� Sctiw, �.� �cv�! � t U �, ,� = 1 a/ . (.� 0 �f ' I � i �� i � . � I 2� � S {1-1 �r w� • ,�I— .�G ' , . � - D. 70,c-�S � Iti - 13. 6Z � - II . �fs = I . � 7 �7� � _ i .; O. 7C7 )� `-1 � �Z i �� �X �. b Z) �Z) 3 2,Z /.67 � �---_ �,_ - ,_; , � RE��R��� = 6, 3723 �. y .� � „ � S E P Q 5 2000 , � �UlLDI�lG DiVISIGh s�_ r�c=� -t��-- ---?� ;�_��.�'�_ .�_� ;�� s —1-- �� ---���.�/o�- - -_ _ � � ' �2 ��5 ,O�r. S �a -�/�,�, 'tG,vp c,cy �i LR,�G S S%���u ,�P� oh �uyu S � 2 �1 i ?OcJO. ' � '� '� r �D lr wi % . � _ � _ ,, � U�-ro� C = C� ts-�o�:+,,r -� �i �.�c��, ��� P - 1. 08c -; • Isf ov�-��� � —> � �U� ' -3� � . � � ��� � ,���� _ �- C �. 37z� - 0. 1 a 9 0�sf . � `� j � j o �t = l `l�to �— f�•qs � = Z.ys�� ; � �� I a C� _ �0��2�C o•Ix1D>f� �<�)C3z. Z)C=�yS)� Z = O, g 5��� � � ' i a � c.> � � L � a�'i 2.�.G�Ov;-��« =� � � � o �� a2�.�I — l, o��!rs — �. �s�s = o, z 3� �s zw � z.,.�( = Iy. 4p �— JS, 7s � _ � 6s�t � .; � _ ��.z3�< �) ��Z ���C o,6z) CZ���,z)�a.6s� �, = O. 2 �0 2 � ti 3_ 2-�t � I � ; �, � dP�s e� Dv�,•��o �v : � • ��o� ,� = I .O�?c-�s '. '� � � �,� _ � �� i � , _ „ �P� s��. - �i a�,-� , � � � F!ow 1�;s -P� �s �. G/-�. �, �a �r�/� -�v� f��. c �. 3, N. � ;S — z . 7� �s i Q / i i .• ;`[�s-� v s� � � ;s QG1 e�t,c C?-�e . � _���e��� 0,�;to�C � 5,�e ' �� �S-� o�; -�<<� �%� - �, y7 i 2K� o�, ��;�� �1,z� = 3 . Z v �. I F�'���' �. � �_ . �,..�.� � SEP05200 ti,��; ��.�,; :��,,,�.�, ,;,, � 8/31/00 3 : 43 : 3 pm Peterson Engineering Consulting page 1 Pacific Gulf , Detention vault Basin 'A' BASIN SUMMARY BASIN ID : A NAN?E : 2 _�r pred2��r site basili :� � SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 41 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 1 . 95 inches AREA. . : 1 . 41 Acres 0 . 00 Acres TIME INTERVAL . . . . : 10 . 00 min CN. . . . : 85 . 00 0 . 00 TC. . . . : 19 . 16 min 0 . 00 min ABSTR.ACTION COEFF: 0 . 20 TcReach - Sheet L: 120 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0100 PEAK RATE : 0 . 16 cfs VOL: 0 . 09 Ac-ft TIME : 480 min BASIN ID: B NAME: 10 yr predev site basin A SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 41 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 2 . 85 inches AREA. . : 1 . 41 Acres 0 . 00 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 85 . 00 0 . 00 TC . . . . : 19 . 16 min 0 . 00 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 120 . 00 ns : 0 . 1500 p2yr: 1 _ 95 s : 0 . 0100 PEAK RATE: 0 . 36 cfs VOL: 0 . 17 Ac-ft TIME : 480 min BASIN ID: C NAME : 100 yr predev site basin A SBUH METHODOLOGY TOTAL AREA. . _ . . . . : 1 . 41 Acres BASEFLOWS : 0 . 00 cfs R.AINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 3 . 85 inches AREA. . : 1 . 41 Acres 0 . 00 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 85 . 00 0 . 00 TC . . . . : 19 . 16 min 0 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 120 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0100 PEAK RATE: 0 .61 cfs VOL : 0 . 27 Ac-ft TIME : 480 min BASIN ID: D NAME: 2 yr postdev site basin A SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .41 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 1 . 95 inches AREA. . : 0 . 20 Acres 1 . 21 Acre� TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC . . . . : 5 . 00 min 5 . 00 m;. �: ABSTRACTION COEFF: 0 . 20 ��'r�`t��� � ' S E P 0 5 2000 __i!L,;If:�c:� J`r'!�S;Of�1 � 8/31/00 3 : 43 : 3 pm Peterson Engineering Consulting page 2 Pacific Gulf Detention vault Basin 'A' , BASIN SUMMARY • BASIN ID: E NAME: 10 yr postdev site basin A SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .41 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 2 . 85 inChes AREA. . : 0 . 20 Acres 1 . 21 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 120 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0001 PEAK RATE: 0 . 78 cfs VOL: 0 . 29 Ac-ft TIME: 480 min BASIN ID: F NAME: 100 yr postdev site basin A SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 41 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 3 . 85 inches AREA. . : 0 . 20 Acres 1 . 21 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 120 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0001 PEAK RATE: 1 . 08 Cfs VOL: 0 .40 Ac-ft TIME : 480 min BASIN ID: G NAME: WQ postdev site basin A SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 41 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 0 . 65 inches AREA. . : 0 . 20 Acres 1 . 21 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 ' TC. . . . : 5 . 00 min 5 . 00 min I ABSTRACTION COEFF: 0 .20 i TcReach - Sheet L: 120 . 00 ns : 0 . 1500 p2yr: 1 . 95 s : 0 . 0001 PEAK RATE : 0 . 13 cfs VOL: 0 . 05 Ac-ft TIME : 480 min _,r,.._, �'�`� qTY O�C ^e r � �� C Zl��F.e��'^ I SEP 0 5 2000 � I � �UILDING DtVIS��N � 8/31/00 3 : 43 : 3 pm Peterson Engineering Consulting page 3 Pacific Gulf � Detention vault Basin 'A' . STORAGE STRUCTURE LIST . RECTANGULAR VRULT ID No. vaultA Description: vault for Basin A Length: 54 . 00 ft . width: 19 . 00 ft . voids : 1 . 000 � � . R���'��� S E P 0 5 2000 � BUILDING DIVfSI�ON II � I 8/31/00 3 : 43 : 3 pm Peterson Engineering Consulting page 4 Pacific Gulf Detention vault Basin 'A' --------------------------------------------------------------------- --------------------------------------------------------------------- , STAGE STORAGE TRBLE • RECTANGULAR VAULT ID No. vaultA Description: vault for Basin A Length: 54 . 00 ft . Width: 19 . 00 ft . voids : 1 . 000 STAG& <----STORAGfi----> STAGH r---STORAGE----> STAGE r---ST'ORAGE----> STAGE <----STORAGE----> (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-F't- (ft) ---cf--- --Ac-Ft-_---(ft)-===cf===-==Ac=F't=--- I ________________________________________________________________________________--------------------- 11.95 0.0000 0.0000 12.90 974.70 0.0224 13.90 2001 0.0459 14.90 3027 0.0695 12.00 51.300 0.0012 13.00 1077 0.0247 14.00 2103 0.0483 15.00 3129 0.0718 12.10 153.90 D.0035 13.10 1160 0.0271 14.10 2206 0.0506 15.10 3232 0.0792 12.20 256.50 0.0059 13.20 1283 0.0294 14.20 2309 0.0530 15.20 3335 0.0765 I 12.30 359.10 0.0082 13.30 1385 0.0316 14.30 2411 0.0554 15.30 3937 0.07F"• 12.40 461.70 0.0106 13.40 1488 0.0342 14.40 2514 0.0577 15.40 3540 0.08: � 12.50 564.30 0.0130 13.50 1590 0.0365 14.50 2616 0.0601 15.50 3642 0.081 12.60 666.90 0.0153 13.60 1693 0.0389 14.60 2719 0.0624 15.60 3745 O.OE 12.70 769.50 0.0177 13.70 1796 0.0412 14.70 2822 0.0648 15.70 3848 D.Oc�- 12.80 872.1D 0.0200 13.60 1698 0.0436 14.B0 2924 0.0671 15.80 3950 0.090? .. -'9T`r"0 REiv:T"V . .. ,. . ; ��-���a��� � � S E P 0 5 2000 � BUILDING DIVISION � � 8/31/00 3 : 43 : 3 pm Peterson Engineering Consulting page 6 Pacific Gulf � Detention vault Basin 'A' --------------------------------------------------------------------- --------------------------------------------------------------------- _ STAGE DISCHARGE TABLE , MULTIPLE ORIFICE ID No. orifA Description: vault flow restrictor Outlet Elev: 11 . 95 Elev: 9 . 95 ft Orifice Diameter: 2 . 1445 in. Elev: 13 . 75 ft Orifice 2 Diameter: 2 . 7598 in. STAGfi r-DISCHARGE---> STAGE c--DZSCHARGH---> STAGE a--DISCHARGE---> ST,AGE r-DZSCHARGE---> !ft) --cfs-- ------ (ft) ---cfs-- ------ (ft) ---cfs-- ------ (ft) --cfs-- ------- 11.95 0.0000 12.60 0.1006 13.30 0.1450 19.00 0.2820 12.OD 0.0279 12.70 0.1081 13.40 0.1503 14.10 0.3053 12.10 0.0483 12.80 0.1151 13.50 0.1554 14.20 0.3259 12.20 0.0624 12.90 0.1216 13.60 0.1603 14.30 0.3446 12.30 0.0738 13.00 0.1279 13.70 0.1651 14.40 0.3620 12.40 D.0637 13.10 0.1336 13.80 0.2160 14.50 0.3793 12.50 0.0520 13.20 0.1395 13.90 0.2543 � �,�.,�::���,�-� _ , SFP () � �000 � i _,;I'--�is•i�_. v?',r'i:.,i�.l!`: ! 8/31/00 3 : 43 : 4 pm Peterson Engineering Consulting page 8 Pacific Gulf � Detention vault Basin 'A' _ LEVEL POOL TABLE SUMMARY � MH'PCH INFIAW -STO- -DIS- <-PEAK-> STORAGE ��:--------DESCRiPTION---------> (cfs) (cfs) —id- --id- c-STAGB> id VOL (cf) _-----_______________________________(- ___,___-----________----------_____ ''%r ��� ��---��...... .......... 0.16 ', 0.51%vaultA orifA 13.62 1 1708.91 cE \_/ lOfr .. . . . . . . . ... . . .. . . . .. . . . . 0.36 0.78 vaul[A orifA 14.40 2 2510.40 cf I �o� _ �z511�1,3} r2� �� �? � �.,5, P�� �ccs�vDM� 1 � ;, � - 3Z �5 G � , —% \ i (Zf-E����� � 32 � 5 - � , l _ D, 1 � � � � � � � .r� V �-c ---- , �z �`�'"� 9) � � � cfA`( 7�, 5 � D� Q�rrt �e _.�-- -- ' ��T�'��`�� �e _ � , S E P 0 5 2000 p � € � �UI�DING DIVISION � _ _....,_.�.--'---, SECTION 5.3 DETENT'ION FACILI7TES . Riser Overflow � The nomograph in Figure 5.3.4.H can be used to determine the head(in feet) above a riser of given (� diameter and for a given flow (usually the 100-year peak flow for developed conditions). `�- � FIGURE 5.3.4.H RISER INFLOW CURVES • �o o ------ 72 54 48 42 36 33 30 . 27 1 . 24 I I � I i 21 � a � _ U � 8 N � h L Q� �. d 10 15 d � � � � � U 0 � 2 � I 10 Z,7 , � I i i t I ��� HEAD IN FEET (measu�red from crest of riser) �� Q w�i,=9.739 D H37z s �is Q,,;�;«=3.782 D H � Q in cfs, D and H in teet Slope change occurs at weir-orifice transition , __.*�'Y.J�-�ElJ.T'.�._. ...�..- : i ���l��Q E 9/II98 5-50 1998 Surface S E P 0 S�n200Q a� , ' t3UILUING DiVISION ?