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AD SYSTEMS EXPANSION EVERETT,WA <br /> Projects shall use Ecology's 2014 Stormwater Management Manual for Western Washington: <br /> Volume I of Section 2.5.5, Chapter 3 of Volume Ill, and Chapter 5 of Volume V to determine which <br /> on-site stormwater management BMPs shall be employed on a particular project site, and <br /> document that determination in the drainage report. <br /> Response: The geotechnical report has been attached in Appendix A for reference. Due to a shallow <br /> impermeable layer with perched groundwater and lack of dispersion area due to existing site constraints, the <br /> LID requirements have been determined to be infeasible. On-site storm water runoff will be collected and <br /> . transported via a system of catch basins and underground storm pipes to the existing storm pond. No <br /> changes to the existing stormwater quality and quantity facilities are proposed. <br /> See below for the flow chart for determining LID MR#5 requirements: <br /> Row Chart for Determining UD MR#5 Requirements <br /> Does the project discharge to Flow Crmhul Exempt Waters <br /> (per Minimum Requirement(MR)NT)?Yes <br /> (4E;QUIR{PLlmptement the following BMus No <br /> where feasible: Does the project trigger only MRs No,the project <br /> BMP 15.13:Post•Corssr uction Sal - lip-PS?(Per Figure 3,2 or Figure triggered only <br /> Quality and Depth 33 in Appendix 1 of the 2013.2018 MR 02 No additional <br /> BMP 15.10A.B.or C;Downspout Full WWA Phase 11 Permit&Phase I requirements <br /> Inhltrabon,Downspout Dispersion permit.{ <br /> Systems,or Perforated Stub-out <br /> Connections / No,the project <br /> • BMP T5.11 or TS:12:Concentrated flaw „triggered Mils pl-k9, <br /> Dispersion or Sheet Flow Dispersion Yes <br /> Is the project inside the UGA? <br /> NOT REQUIRED:Achievement of the LID <br /> Performance Standard.Applying the other / No,the project is <br /> BMPs in List Pl or List N o2. aside the UGA. <br /> Yes <br /> Did the project developer choose to meet the • <br /> LID Performance Standard? k the project on a parcel of <br /> 5 acres or larger? <br /> No,project developer No <br /> chose List p1., Yes Yes <br /> Did the project developer <br /> $Ef21lIRED;For each surface, choose to meet the LID REQUIRED;Meet the LID <br /> consider the BMPs In the order <br /> Performance Standard? Performance Standard through the <br /> listed in List 81 for that type of <br /> surface.Use the first BMP that is use of 9L'Y E{MP(sj in the 2014 <br /> considered feasible. Yes SW W MMW except for Pain Gardens <br /> No,project (the use of Bioretenton n <br /> NOT REQUIRED:Achievement of developer acceptablrj. <br /> the LID Performance Standard, chose List PT. <br /> lithe project can't meet the LID <br /> Performance Standard,it must seek <br /> REQUIRED;Meet theft()Performance REQUIRED:For each surface, and be granted an exception I <br /> Standard through the use of any BMP(s)In consider the BMPs in the variance. <br /> the 2014 SW MMW W except for Rain Gardens order listed in List N2 for <br /> (the use of Ftioretention is acceptable). that type of surface.Use the REQUIRED:Apply BMP T5.13 Post- <br /> REQUIRED for Protects Triggering MR u1-9h first BMP that is considered Construction Solt Quality and Depth. <br /> feasible. <br /> Apply BMP T513 Post-Construcbcm Soil NOT REQUIRED;Applying the BMPs <br /> Quality and Depth, NOT REQUIRED; in List al or List 02, <br /> Achievement of the LID <br /> NOT REQUIRED;Applying the BMPs in List P1 <br /> Performance Standard. <br /> or List 42, <br /> 'Recommended by Ecology for projects triggering MR thl•5, <br /> Figure 2.5.1 —Flow Chart for Determining LID MR#5 Requirements <br /> NOVEMBER 20, 2017 STORMWATER DRAINAGE SUMMARY PAGE 7 <br />