Section 12.16.150 General performance criteria.

Unless judged by the environmental services department to be exempt or granted a waiver, the following performance criteria shall be addressed for storm water management at all sites:

1. All site designs shall establish storm water management practices to control the peak flow rates of storm water discharge associated with specified design storms and reduce the generation of storm water. These practices should seek to utilize pervious areas for storm water treatment and to infiltrate storm water runoff from driveways, sidewalks, rooftops, parking lots, and landscaped areas to the maximum extent practical to provide treatment for both water quality and quantity.

2. New development shall minimize discharge of untreated storm water directly into a jurisdictional wetland or local water body. Where such discharges are proposed, the impact of the proposal on wetland functional values shall be assessed using a method acceptable to the environmental services department. In no case shall the impact on functional values be any greater than allowed by the Army Corps of Engineers (USACE) or the appropriate state agency responsible for natural resources.

3. To protect stream channels from degradation, a specific channel protection criteria shall be provided as prescribed in the current storm water manual.

4. Development sites are required to prepare and implement a storm water pollution prevention plan, and shall file a notice of intent under the provisions of the National Pollutant Discharge Elimination System (NPDES) general permit filed with the Iowa Department of Natural Resources. This is a federally enforceable requirement administered by the city beginning March 10, 2003. The storm water pollution prevention plan requirement applies to both existing and new industrial sites and construction sites greater than one acre.

5. Storm water discharges from land uses or activities with higher potential pollutant loadings, known as "hotspots", may require the use of specific structural treatments and pollution prevention practices.

6. Prior to design, applicants are required to consult with the environmental services department to determine if they are subject to additional storm water design requirements.

7. The calculations for determining peak flows as found in the storm water design manual shall be used for sizing all storm water management practices.

8. That the proposed development is in compliance with the City flood plain ordinance.
9. If water supply is an issue, the storm water management plan should include provisions for beneficial use of storm water where practical. (Ord. 2002-1015)