2901 LOWELL-SNOHOMISH RIVER RD 2022-07-20

Lowell Riverfront Off-Leash Dog Area 2 Stormwater Mitigation Threshold Evaluation Minimum Requirements The Small Project Site Plan/Report form (Attachment D)was prepared to show compliance Minimum Requirements#1-5. The following highlights key information from the form. Minimum Requirement#2—Construction Stormwater Pollution Prevention Plan(SWPPP) Parks will be responsible for preventing erosion and sedimentation during construction, including these activities: • Minimize construction track-out.BMP C105: Stabilize construction entrance/exit. • Construction staging and stockpiling will be located within previously disturbed areas and outside sensitive areas. • BMP C151 and BMP C154 will be used for concrete handling concrete washout activities,respectively. • Any materials needed for erosion prevention and sedimentation control will be kept at the project site (BMP C150). • Construction sequencing will be done in a manner that reduces the amount and duration of soil exposed to erosion by wind,rain,runoff,and vehicle tracking(BMP C162). Minimum Requirement#3 —Source Control BMPs Parks must apply these Source Control BMPs to the project site: • Section V-1 Source Control BMPs Applicable to All Sites (e.g., good housekeeping, employee training, inspections, recordkeeping, etc. which are a part of Parks' normal operations) • S411 BMPs for Vegetation Management(which are a part of Parks' normal operations) • S440 BMPs for Pet Waste Minimum Requirement#5—On-Site Stormwater Management On-site Stormwater Management BMPs is required for lawn and landscaped areas and hard surfaces. The project discharges to the Snohomish River,which is a flow control exempt receiving water per Table I-A.1 in the Manual.As such,the following BMPs in List#3 will apply to the project: • The project will need to meet soil requirements for the disturbed vegetated areas as listed in BMP T5.13: Post-Construction Soil Quality and Depth. • For the concrete pads,the project meets the requirements for BMP T5.12: Sheet Flow Dispersion. The site will be graded to avoid concentrated flows and has adequate vegetation buffer area.