Chapter 161 – Post Construction Storm Water Runoff Control

the discharge of storm water from a Municipal Separate Storm Sewer System (MS4) Permit. The City is subject to the NPDES permit program. 2. 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. 3. Therefore, the City establishes this set of City storm water standards applicable to all surface water 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 erosion, and nonpoint source pollution associated with storm water runoff, is in the public interest and will prevent threats to public safety and welfare. 4. 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 upon 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 for the BMP will be deemed to have been installed in accordance with this chapter. 161.03 APPLICABILITY. 1. This chapter is applicable to all land-disturbing activities greater than one acre or part of a larger common plan of development. In addition, this chapter also applies to all applications for site plans or subdivisions that are less than one acre, and are commercial, industrial or multi-family residential uses as defined by the Tiffin Zoning Code, unless requirements of this chapter have been met through approved use of an off-site location. 2. Any development within a preliminary or final plat approved prior to the adoption of this chapter will be deemed exempt from the requirements of this chapter. Re-subdivision of lots within an approved platted area and amendments to plats approved prior to the adoption of this chapter must conform to this chapter, unless determined by the City to be minor in nature. 3. For developments where the runoff from up to and including the 100-year storm event can be conveyed directly to local creeks without adverse impact to intervening property, no overbank flood protection control is required. In this case, the developer must show by hydrograph analysis that the runoff from the development