EXH0297019894

5808 Lake Washington Blvd. NE, Suite 200 Kirk/and,Washington 98033-7350 Aqua Terra Consultants 6140 CapitalBlvd. SE, Suite D Tumwater, Washington 98501 Earth Tech, Inc. 10800NE 8_ Street,SeventhFloor Bdlcwe, Washiugton 98004 Foster Wheeler Environmental Corporation 12100NE 195_ Street, Suite 200 Bothdl, Washifigton 98011 HIVrB 600 108_ Avenue NE, Suite400 _Bellevue,W_¢hi_gton 98004 Pacific Groundwater Group 2377 EasflakeAvenue East Seattle,Washington 98102 : December 2001 556-2912-001 (28B) AR 019896 m CERTIFICATE OF ENGINEER Theteohnicalmaterialand datacontainedin thisdocumentwerepreparedunderthesupervisionand directionof the undersigned,whoseseaL,as a profe._ionalengineerlicensedto prance as such, is affixedbelow. ft_ k- • ._'%X_-_, '_61___ ._,t_.. . 2.'r_12 .. j [ _._._=.: _Y'-,7--o'3 [ PaulS.Fcndt,P.E. Low ,_trenmflowAnal3ai_ December 2001 Master Plan Update Improvement_ __6-2912.001(28B) AR 019897 TABLE OF COI_I_NTS Page EXECUTIVE SUMMARY.................................................................................................................vi 1. INTRODUCTION................................................................................................................1-1 1.1 PURPOSE ............................................................................................................... I-1 1.2 ORGANIZATION OF REPORT........................................................................... 1-1 1.3 REL_TIONSI-HP TO OTHER.DOCUMENTS...................................................... t-1 1.4 PROJECT DESCRIPT/ON ......................................................................................1-3 2. LOW STRE.MvlFLOWANALYSIS ................................................................................ 2-1 2.1 APPROACH ............................................................................................................ 2-1 2.1.1 Introduction .............................................................................................. 2-1 2.1.2 Detwrn_nation of Summer Low-Stmamflow Period ................................... 2-1 2,1.3 Existing Summer Low Streamflows ........................................................... 2-2 2.2 HSPF MODEL CALIBRATION ............................................................................ 2-2 2.2.1 Overall Model ..............................................................................................2-2 2.2.2 Low-Flow Review....................................................................................... 2-2 2.3 EMBA_NK.ME_NTMODELING.:.............................................................................2-6 2.4 NON-HYDROLOGIC IMPACTS......................................................................... 2-8 2.4.1 Cessation of Water Withdrawals .................................................................2-8 2.4.2 P,.ernovalof Septic TankDischarges ............................................................2-9 2.4.3 SummaryofNon-Hydrologic Impacts ......................................................2-10 2.5 SLqVlM,M_YOF NET IMPACTS TO CREEKS................................................. 2-10 2.5.1 Summary of Flow Impacts......................................................................... 2-10 2.5.2 Summary of Water Level lrapaets ............................................................. 2-13 3. MITIGATION PROPOSAL .................................................................................................3-1 3.1 INTRODUCTION OF APPROACH..................................................................... 3-1 3.2 PER.FOR_MANCESTANDARDS .......................................................................... 3-t 3.3 WATER QUANTITY - VAULT SIZING ANALYSIS .........................................3-1 3.3.1 Vanlt Sizing..................................................................................................3-2 3.3.2 Vault Fill Time .............................................................................................3-2 3.4 WATER QUALITY'DESIGN .................................................................................3-3…

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PSCAA Advisory Council Meeting Agenda
Add to CalendarMWednesday Mar 11, 9:00am - 11:35am
1904 3rd Avenue, Suite 105, Seattle, WA 98101
Call to order – Roll Call – Quorum Established – Land Acknowledgement We would like to acknowledge that our Agency operates in four present-day counties, which are the traditional lands of the Coast Salish people, past and present. This acknowledgement does not take the place of authentic relationships with indigenous communities in our jurisdiction and [...]