2003-04-01 P & Z Agenda - Laserfiche WebLink

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waste at the construction site that may adversely impact water quality, preferable before construction activity begins on a site. Small MS4s operators may choose to impose more prescriptive requirements than an NPDES permitting authority based on localized water quality needs. As a result of this provision, local requirements will, in effect, provide the substantive construction site erosion and sediment control requirements for the NPDES permit authorization. In areas where the local authority does not choose to participate, the State administers the sedimentation and erosion control requirements. The rule also gives NPDES permitting authorities discretion not to require the submittal of a notice of intent (NOl) for coverage under a NPDES general permit, thereby reducing administrative and financial burden. However, all construction sites disturbing an area greater than 5 acres must submit an NO!. Post-Construction storm water management in new development and redevelopment areas also must develop, implement, and enforce a program to address storm water runoff from new development and redevelopment proj ects that disturb greater than or equal to one acre, including projects less than one acre that are part of a larger common plan of development or sale, that discharge into the small MS4. The rule does allow for deviation from the default standard through additional designations and waivers, however, when supported by location-specific water quality information. The rule codifies the ability of permitting authorities to provide waivers for sites greater than or equal to one acre (the default standard) and designate additional discharges from small sites below one acre when location-specific information suggests that the default 1 acre standard is either unnecessary (waivers) or too limited ( designations) to protect water quality. Exemptions In today's rule, EP A is regulating storm water discharges from additional construction sites to better protect the Nation's waters, while remaining sensitive to a concern that the Agency should not regulate discharges from construction sites that might not or do not have adverse water quality impacts. These construction-related storm water sources are regulated under CWA section 402(P)(6) gives States and EPA the flexibility to waive the permit requirements for construction activity that is not likely to impair water quality, and to designate additional sources below one acre that are likely to cause water quality impairment. Storm water discharges from construction activity equal to or greater than I acre and less than 5 acres are automatically designated except in those circumstances where the operator certifies to the permitting authority that one of two specific waiver circumstances applies, while sites below one acre may be designated under 122.26(b)(l5)(ii) where necessary to protect water quality. The first waiver is based on "low predicted rainfall erosivity", which can be found using tables of rainfall-runoff erosivity (R) values published for each region in the U.S., and is