5003 OCEAN AVE 2023-11-01 - Laserfiche WebLink

7. ON -SITE STORMWATER MANAGEMENT As documented in Section 1 of this report this project is required to meet Minimum Requirements 1-5. As a result, this project is required to use the On -Site Stormwater Management BMP's from 2019 DOE SWMMVWV. Per the DOE SWMMVWV, the BMP's must be evaluated in the order they are listed. BMP's for roofs: 1. Full Dispersion: Not feasible due to the 65:35 requirement. 2. Downspout Infiltration Systems: As mentioned in Section 2, the soils were found to be sandy loams with an approximate depth to water table of 18 to 36 inches. The minimum required vertical separation cannot be provided. Due to the soil conditions of the site infiltration is not feasible for this project. 3. Rain Gardens and Bioretention: Similar to Downspout Infiltration systems, the soil conditions of the site make rain gardens and bioretention not feasible for this project. 4. Downspout Dispersion Systems: Infeasible, as minimum flow paths cannot be provided due to the site constraints. 5. Perforated Stub -out Connections Feasible and selected for this project. The roof runoff shall be directed to a perforated stub out trench on the west side of the proposed SFR then connected to the existing stormwater drain on Ocean Ave. BMP's for other surfaces: 1. Full Dispersion: Not feasible due to the 65:35 requirement. 2. Rain Gardens and Bioretention: Similar to Downspout Infiltration systems, the soil conditions of the site make rain gardens and bioretention not feasible for this project. 3. Sheet Flow Dispersion: This project will disperse runoff from the driveway by sheet flowing to the east Finally, any area of the site not proposed to be covered with impervious surfaces but graded or compacted will be treated to meet the criteria for BMP 12.20. Please refer to the engineering plans for basic soil amendment notes. Ocean Ave SFR 21-0634 February 2022 Page 9