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focus on infiltration BMPs. If Hydrologic Soil Group C & D soil is present onsite the stormwater management plan would focus on water quality BMPs (not limited to NURP ponds, but instead encouraging/requiring other practices such as tiltration, extended detention basins, wetland treatment systems, etc.). In both cases, the sizing of these BMPs would be based on the runoff volume generated (under proposed conditions) from the 2-year (2.8-inch) storm event. The simplifying logic behind this condensing of standards is three-fold: I) infiltration practices also provide a water quality benetit, 2) intiltration practices have the highest success in Hydrologic Soil Groups A & B, and 3) overall, the combination of these standards will result in essentially the same volume reduction and water quality treatment as a standard that compares existing conditions to proposed conditions (for all soil types for this storm event). Regardless of the soil group present onsite, the applicant would be required to demonstrate an attempt to minimize imperviousness and incorporate low impact development (LID) practices. Rule language would also include an out clause for infiltration requirements where high groundwater or contaminated soils are present. An idealized flow chart for this combined standard is provided below. Figure 3. Proposed Storm water Rule Flow Chart INCORPORATION OF LID PRACTICES & ONSITE SOIL DETERMINATION AlB SOILS C/O SOILS 20% Pretreatment 80% Infiltration 20% Filtration 80% Retention Stormwater Management Criteria for Redevelopment It is recommended that the District's redevelopment criteria (currently the same as development criteria) should be revised and expanded upon to clearly detine stormwater management requirements. The recommended redevelopment stormwater management goal is the same as outlined above for new development. The recommended redevelopment stormwater management minimum standard is 70% of the goal. This minimum standard would provide some flexibility for redevelopment recognizing that these areas typically do not have any existing stormwater management provisions and that incorporation of storm water management provisions would be an improvement over existing conditions. At the same time this minimum standard would provide, at least initially, the same level of treatment as NURP standards (without sediment storage). If a redevelopment did not achieve the District's stormwater management goal, but only complied with the minimum standard, then an increase in maintenance frequency should be required. Exceptions for maintenance activities such as resurfacing parking lots and roofs, and a Emmons & Olivier Resources, Inc. Page 4 of8