12-14-2022 Council Packet - Laserfiche WebLink

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(3) Off-site treatment projects must be completed no later than 24 months after the start of the original construction activity. If you determine that more time is needed to complete the treatment project, a reason must be provided and a schedule for completing the project in the annual report. (4) If the City of Little Canada receives payment from the owner of a construction activity for off-site treatment, the City must apply any such payment received to a public stormwater project, and all projects must comply with this ordinance. 5. Water Quality - Developments must incorporate effective non-point source pollution reduction BMPs to achieve 90% (new construction) or 45% (redevelopment) total suspended solids removal from the runoff generated by a NURP water quality storm (2.5” rainfall). Runoff volume reduction requirement may be considered and included in the calculations showing compliance with achieving the 90% TSS and/or 45% TSS removal requirement. Water quality calculations, documentation and/or water quality modeling shall be submitted to verify compliance with the standard. 6. Runoff rate control – hydrologic calculations - A hydrograph method based on sound hydrologic theory shall be used to analyze runoff for the design or analysis of flows and water levels. 7. Runoff rate control - design standards - Runoff rates for the proposed activity shall not exceed existing runoff rates for the 2-year, 10-year, and 100-year critical storm events, and runoff rates may be restricted to less than the existing rates when the capacity of downstream conveyance systems is limited. 8. Outlets - Discharges from new construction sites must have a stable outlet capable of carrying designed flow at a non-erosive velocity. Outlet design must consider flow capacity and flow duration. This requirement applies to both the site outlet and the ultimate outlet to stormwater conveyance or waterbody. 9. Pond Requirements – For all projects creating more than one acre of impervious surface, ponding shall be required. At a minimum all pond design specifications shall conform to the current City and NPDES construction permit requirements. In addition the following are required: 1. A bench shall be provided starting at the normal water level and ending 1 foot below normal water level with side slopes no less than 10 feet horizontal to 1 foot vertical (10:1) for safety considerations. Pond side slopes shall not exceed 4 feet horizontal to 1 foot vertical (4:1) without approval of the City. 2. All public and private owned stormwater management facilities shall provide an unobstructed access path (minimum of 10 feet) capable of supporting light truck traffic during normal weather for the purpose of conducting inspections of the facility and maintenance thereof. No private