EXH0461022933

Review Comments on the Low Flow Impact Analysis - Flow _xHmrr Impact Offset FacilityProposal,July 2001 | M. Green • Review Scope and Limitations The3uty 200I Low Row AnalysisFlow ImpactOffsetFacilityProposal(LowFlow Report) has been reviewed for consistency in hydrologicmodelingand for consistencyin meetingthe perfonnanee objectives identifiedby the Departmentof Ecology (Ecology)and Portof Seaale (Port). The Low Flow Report supplements thePort'sComprehensiveStormwatcrManagementPlan (SMP). While the 1998 King County SurfaceWaterDesign Manual (KCSWDM)does not includeperformancestandardsfor low flow mitigations, the fol]owing commentsdo includesome referencesto KCSWDMdesigncriteria. This review summax7 concludes thatthe low flow reportproposessubstantial mitigationsfor offsetting low flow impacts annually din'lagthe timeperiodwhen most towflow events occur. Them arc, however,some significant gaps in the documentationof theanalyses performedand the associated mitigations. This enclosuresummarizeskey findingsandrecommendationsgeneratedfrom thisreview. These comments includea substantialamount of commentaryas to the reviewers understandingof the analyses performed. Review has been limitedto the FISPFhydrologicmodeling,the impactassessment,andthe conceptual designof theassociated facilities. With the exceptionof thehydrologicinputsandoutputs,the review of specific aspects ofti_ embanlmcnt modelingused inMiger Cr_k was igdormed byEcology staff with e.xpertis¢in that area. Reviewof a stormwatermanagementplan isprimarilya l'¢viewof designconcepts and assumptions to determineif the proposedmitigationsdemonstratea feasibleapproachto complywith the identified performancegoals. As the proposedMasterPlan Update (bIPLT)developmentprojex.-tsmove from the .... planning stages to developmentof constructionplans, theproposedlow-flowmitigadons may nccd to be updatedto reflect any clmag¢in conditions. Priorto constructionof specificprojects, additionalreview and approvalof thefinal constructiondrawingsandassociatedtechnicalinformationreportis typically required.Oversightand monitoringare key elements tosuccessful implementationof any stormwater managamcntplan. It is reconunendedthatEcology and thePortdevelopa plan to oversee andmonitor compliance with the mitigationsset forthin the StormwaterManagementPlan andLow Flow Report.One option is tocreate an Ecology "ComplianceTeam",representingthe nacessarydisciplines, to work with the Port toachieve compliance with…

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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 [...]