902 PINE ST NORTH SOUND BEHAVIORAL HEALTH TREATMENT CENTER 2025-11-04

I • Wetlands Inventory: No wetlands are present within 1 mile of the project site area, as I shown on the US Fish and Wildlife Service National Wetlands Inventory (see Appendix A-10). • City of Everett Drainage Complaints: As recorded in the Public Works Interim Policy 2-11, heavy storms have caused localized surcharges in the existing combined storm/sewer system, flooding basements and streets in North Everett. 3.3 Task 3—Field Inspection 3.3.1 Upstream Field Inspection I Based on the topographic and existing conditions, the onsite existing parking lot drains toward the project site via sheet flow. The project drainage system will bypass upstream flows around the project site. 3.3.2 Downstream Field Inspection A downstream analysis was not performed because the stormwater discharges into sanitary I approximately 390 feet from property line. Refer to Appendix A-4 for a Downstream Study Map. Below are summaries of the review of other available resources: I 1. Investigate any problems reported or observed during the resource review. • No problems were reported or observed during the resource review. 2. Locate all existing/potential constrictions or lack of capacity in the existing drainage system. • According to the record of City of Everett, heavy storm events have caused localized surcharges in the combined sewer system and flooded basements and streets in North Everett. Controlling stormwater discharges to the CSO system has been required by the City to mitigate the impacts by the lack of capacity in the existing combined storm/sewer system. 3. Identify all existing/potential flooding problems. I • No existing flooding problems were identified during the field inspection. • Per the FEMA Flood Map (Appendix A-6), the project area, as well as 1 mile downstream of the project, is located in Zone X. Because of this classification, the area is determined to be outside the 500-year floodplain • The basin is not within the 100-year flood zone. 4. Identify existing/potential overtopping, scouring, bank sloughing, or sedimentation. I • No existing or potential overtopping, scouring, bank sloughing, or sedimentation was observed in the downstream system. I 5. Identify significant destruction of aquatic habitat or organisms. • No areas of significant destruction were identified, including siltation, bank erosion, or incision in a stream. Stormwater Site Plan Report North Sound Behavioral Health Treatment CJ(JØ AHBL No.2170857.10