1. The United States Environmental Agency’s (EPA) National Pollutant Discharge Elimination System (NPDES) permit program administered by the Iowa Department of Natural Resources (IDNR) requires that cities meeting certain demographic and environmental criteria obtain from the IDNR an NPDES permit for the discharge of storm water from a Municipal Separate Storm Sewer System (MS4) Permit. The City is subject to the NPDES permit program and is required to obtain, and has in fact obtained, an MS4 permit; the City’s MS4 permit is on file at the office of the City Clerk and is available for public inspection during regular office hours.
2. As a condition of the City’s MS4 permit, the City is obliged to adopt and enforce a Post-Construction Storm Water Runoff Control Ordinance.
3. Land development and associated increases in impervious cover alter the hydrologic response of local watersheds and increase storm water runoff rates and volumes, flooding, stream channel erosion, and sediment transport and deposition; this storm water runoff contributes to increased quantities of waterborne pollutants; and storm water runoff, soil erosion, and nonpoint source pollution can be controlled and minimized through the regulation of storm water runoff from development sites.
4. Therefore, the City establishes this set of City storm water standards applicable to all surface waters to provide for reasonable guidance for the regulation of storm water runoff for the purpose of protecting local water resources from degradation. It is determined that the regulation of storm water runoff discharges from land development and other construction activities in order to control and minimize increases in storm water runoff rates and volumes, soil erosion, stream channel erosion, and nonpoint source pollution associated with storm water runoff, is in the public interest and will prevent threats to public safety and welfare.
5. The determination of appropriate minimum storm water management standards and the development of effective best management practices to achieve those standards require technical expertise that may not always be readily available with the City’s own staff. Moreover, it is important that such standards and BMPs be reasonably consistent across the State so that property owners and developers are not confronted with myriad variations depending on the location of the development. The Iowa Storm Water Management Manual, published collaboratively by the Iowa Department of Natural Resources and the Center for Transportation Research and Education at Iowa State University established guidelines consisting of unified sizing criteria, storm water management designs and specifications, and BMPs. The City hereby finds and declares that the Iowa Storm Water Management Manual and future editions thereof, should be and is hereby adopted as the storm water management standards of the City. Any BMP installation that complies with the provisions of the Iowa Storm Water Management Manual, or future editions thereof, at the time of installation of the BMP shall be deemed to have been installed in accordance with this chapter.