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t <br /> Technical Memorandum Perteet <br /> 2707 Colby Avenue,Suite 900,Everett,WA 98201 I P 425.252.7700 I F 425.339.6018 <br /> Table 1 -Existing Conditions <br /> Non-Pollution Pollution Total Existing <br /> Generating Generating Impervious Area <br /> Impervious Surface Impervious <br /> (NPGIS) Surface(PGIS) <br /> Community 2,482 SF 4,582 SF 7,064 SF <br /> Transit Parcel <br /> City of Everett 6,285 SF 9,862 SF 16,147 SF <br /> ROW <br /> Project Total 8,767 SF 14,444 SF 23,211 SF <br /> Table 2 below summarizes the new impervious areas associated with the proposed improvements, which are <br /> shown in Figures B-1 and B-2— Proposed Impervious Areas in the Appendix B of this memorandum. <br /> Table 2-Proposed Conditions <br /> New Non-Pollution New Pollution Total New <br /> Generating Impervious Generating Impervious Area <br /> Surface(NPGIS) Impervious <br /> Surface(PGIS) <br /> Community Transit Parcel 28,163 SF 61,632 SF 89,795 SF <br /> City of Everett ROW 4,161 SF 3,345 SF 7,506 SF <br /> Project Total 32,324 SF 64,977 SF 97,301 SF <br /> The following project level threshold analysis is a step-by-step procedure used to determine which minimum <br /> requirements this project must satisfy. This procedure follows the Minimum Technical Requirement flow charts <br /> (Figures 2.1 through 2.2) in Chapter 2 of the COE SWMM. The areas listed in Tables 1 and 2 above are used in <br /> the following analysis. <br /> Table 3-Minimum Requirements(MR)Applicability Procedure-Project Level <br /> Questions _ Response Action Required <br /> Question 1: Yes. The project site will See Minimum <br /> Does the project have 5,000 square feet or add 61,632 SF of new Requirement#6. <br /> more of new,replaced,or new plus replaced PGIS. Continue to Question 2. <br /> pollutant generating impervious surface? <br /> Question 2: Yes. The project will add See Minimum <br /> Does the project add 5,000 square feet or a total of 89,795 SF of new Requirements#1 <br /> more of new impervious surfaces? impervious surface. through#9. All <br /> Minimum Requirements <br /> apply to the new <br /> impervious surfaces and <br /> converted pervious <br /> surfaces. <br /> Page 3 <br /> File location: X:\Community Transit\Projects120110155-Community Transit On-Call\.016-Seaway Transit Center Preliminary <br /> Engineering\Design\Drainage\1_Threshold Analysis\TechMemo 06242016.docx <br />