2600 FEDERAL AVE 2021 PORT OF EVERETT 2025-09-29

1q:1 Consulting Engineers Page 6 of 13 Table 5: Developed Basin A Site Area Area Description Area Land Type (ac) Warehouse and South Parking Lot 3.11 Non-PGIS South Parking Lot 0.75 Undisturbed PGIS Southern Cargo Laydown 0.25 New/Replaced PGIS Total On-site Area 4.11 See above Total Off-site Area 0.13 Undisturbed PGIS Total Basin Area 4.24 Total new/replaced PGIS 04 Total non PGIS(warehouse roof) 1 3.11 Federal Avenue developed conditions will consist of pavement replacement, shoulder widening and utility construction. The work will occur in basins 1 &2 as illustrated on Figure 3 in Appendix A. Basin 1 work will include construction of a new catch basin (CB23) on the west side of Federal Avenue. CB23 will collect drainage from the 4,145 sf of new& replaced PGIS. CB23 will be tight lined to a new Port stormfilter(SDMHB) that will treat the drainage before discharge to Port Outfall A. As noted earlier, drainage from Basin 1a currently drains to Port properties to the west and north, untreated,where it is generally infiltrated. Basin 2 work consists of about 8,510 sf of new& replaced PGIS for shoulder widening and utility construction. Basin 2 runoff flows to existing catch basins that will connect to a planned City of Everett modular wetland regional facility.The Modular Wetland may be used to meet Minimum Requirement No. 6 (MR 6) in Section 4.0 to treat Federal Avenue improvements if the Modular Wetland is online before Port construction is complete by approximately October 2022. If the City project is abandoned,the Port will provide a back-up 'Basic' treatment proposal to meet the MR6 requirement. The back-up 'Basic' treatment facility would be constructed late 2022 or early 2023 and would only be constructed if the City's regional facility is abandoned. See MR 6 on Page 8 for further information. 4.0 Minimum Requirements (#1 through #9) Based on the 2019 Stormwater Management Manual for Western Washington as prepared by the Washington State Department of Ecology and as amended by City of Everett Ordinance 3168-10 (Chapter 14.28 EMC), it is determined that Minimum Requirements #1 through #9 apply to this project. Each requirement is described below. Minimum Requirement#1: Preparation of Stormwater Site Plans: Stormwater site plans have been prepared and are included in Appendix B of this report. As described above, new stormwater infrastructure is being installed as part of this project. Refer to section 3.0 and Appendix B for details of the stormwater infrastructure installation.