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Little Canada Zoning Code Stormwater Management <br /> 928-8 <br /> <br />Table 2. Alternative Compliance Site Conditions* <br />Type Specific Site Conditions Submittal Requirements <br />Potential Contamination <br />Potential Stormwater Hotspots <br />(PSHs) <br />PSH locations and flow paths <br />Contaminated Soils State Permitted Brownfield <br />Documentation, Soil Borings <br /> <br />Physical Limitations <br />Low Permeability (Type D Soils) Soil Borings <br />Bedrock within 3 vertical feet of <br />bottom of infiltration area <br />Soil Borings <br />Seasonal High Groundwater <br />within 3 vertical feet of bottom of <br />infiltration area <br />Soil Borings <br />Karst Areas Soil Borings <br /> <br />Land Use Limitations Utility Locations Site Map <br />Adjacent Wells Well Locations * Alternative Compliance is allowed for the volume reduction portion only. <br /> <br />Alternative Compliance Sequencing. To the maximum extent practicable, <br />the volume reduction standard shall be fully met onsite. <br /> <br />2. Water Quality - Developments must incorporate effective non-point source <br />pollution reduction BMPs to achieve 90% (new construction) or 45% <br />(redevelopment) total suspended solids removal from the runoff generated by a <br />NURP water quality storm (2.5” rainfall). Runoff volume reduction requirement <br />may be considered and included in the calculations showing compliance with <br />achieving the 90% TSS and/or 45% TSS removal requirement. Water quality <br />calculations, documentation and/or water quality modeling shall be submitted to <br />verify compliance with the standard. <br /> <br />3. Runoff rate control – hydrologic calculations - A hydrograph method based on <br />sound hydrologic theory shall be used to analyze runoff for the design or <br />analysis of flows and water levels.. <br /> <br />4. Runoff rate control - design standards - Runoff rates for the proposed activity <br />shall not exceed existing runoff rates for the 2-year, 10-year, and 100-year <br />critical storm events, and runoff rates may be restricted to less than the existing <br />rates when the capacity of downstream conveyance systems is limited. <br /> <br />5. Outlets - Discharges from new construction sites must have a stable outlet <br />capable of carrying designed flow at a non-erosive velocity. Outlet design must <br />consider flow capacity and flow duration. This requirement applies to both the <br />site outlet and the ultimate outlet to stormwater conveyance or waterbody. <br /> <br />6. Pond Requirements – For all projects creating more than one acre of impervious <br />surface, ponding shall be required. At a minimum all pond design specifications