3315 BROADWAY HOPEWORKS STATION 2 2020-12-21

1 4. MINIMUM REQUIREMENTS This project is classified as a Large Project because it will create more than 5,000 sq. ft. of new hard surface, and will be required to meet all of the following minimum requirements as applicable. DOE flow charts were reviewed and are provided in the appendix. MR 1: Preparation of Stormwater Site Plans Stormwater site plans showing how stormwater will be collected and conveyed to the public storm sewer will be prepared in accordance with DOE and City of Everett standards upon finalization of the site configuration. MR 2: Construction Stormwater Pollution Prevention The site construction plans will include TESC provisions with notes and details. A Construction Stormwater Pollution Prevention Plan (CSWPPP) also will be prepared. The proposed BMPs will include siltation barriers, an armored construction entrance, inlet protection and covering of exposed soil. Dewatering is not anticipated to be required during construction, but in the event that it is required measures to handle dewatering will be detailed. This project will not require a Construction Stormwater General Permit (NPDES) from the Department of Ecology because it encompasses less than one acre. MR 3: Source Control of Pollution The CSWPPP will include provisions for materials handling and pollution source control L during construction. Any hazardous material releases shall be contained, cleaned up, and reported. The CSWPPP will provide details on how the following requirements will be met: • Monitoring plan. • Designated project contact. • Secondary containment. • Provisions to secure hazardous materials. I • Response to leaking vehicles and equipment. • Practices and procedures regarding transfer of flammable and combustible liquids. • On-site cleanup materials and other containment and cleanup provisions. The operation of the completed building is not expected to generate significant pollutants on an ongoing basis. MR 4: Preservation of Natural Drainage Systems and Outfalls There are no surface channels on the project site or the downstream drainage path. Stormwater runoff from the site is conveyed via the City Everett combined sewer system to the Water Pollution Control Facility. At 36th Street and Riverbend Blvd. there is a pumping station that transfers the gravity flow to pressure flow. At this location the is a combined sewer overflow to the Snohomish River(SR08). This outfall is a 60" concrete pipe and records indicate it was installed in 1914. Hopeworks II DCI Engineers Page 4 Storm Drainage Report