2026 05 Storm Water Management Report rcd 5 6 2026

Point of Analysis #3 Study Area 3: This area consists of 0.076 acres which includes lawn area that sheet flows to the northeast corner of the site and is not collected by the onsite stormwater conveyance system. Proposed Conditions Input Summary Table Drainage Area Drainage Time of Curve Number Name Area Concentration (CN) (acres) (minutes) PDA 3 – Pervious 0.076 8.5 80 Proposed Conditions Flow Summary Table Drainage Current Adjusted Rainfall Projected Adjusted Rainfall Area Conditions Conditions Name Q2 (CFS) Q10 (CFS) Q100 (CFS) Q2 (CFS) Q10 (CFS) Q100 (CFS) POI #3 0.13 0.25 0.52 0.17 0.33 0.69 5. Stormwater Management System Design A summary of each basin’s water surface elevation (WSEL) and outflow rates for the Water Quality, 2-, 10-, and 100-year storm event for both current and projected conditions are provided below. These WSELs and outflows assume normal operating conditions for each basin. In addition, the emergency spillway water surface elevation and outflow for the projected 10-year storm event have been calculated assuming the outlet structure has failed and there is no storage below the emergency spillway. Routing calculations for the basins and emergency spillway calculations are included in the Appendix. Bioretention Basin Summary Table Storm Event (years) Water Surface Elevation (ft) Outflow (CFS) Water Quality 622.79 0.00 Current – 2 623.12 0.24 Current – 10 623.29 0.47 Current – 100 623.54 0.85 Projected – 2 623.19 0.33 Projected – 10 623.36 0.57 Projected – 100 623.69 1.07 Mavis Tire Supply, LLC

623.36 0.57 Projected – 100 623.69 1.07 Mavis Tire Supply, LLC July 2025 DEC# 1956-24-04187 6 Last revised May 2026