(A) A comprehensive guide to managing stormwater on post-development sites has been developed by the State Department of Natural Resources. The Iowa Stormwater Management Manual can be found on the Internet at: http://www.ctre.iastate.edu/pubs/stormwater/index.cfm. Rate control measures listed in this guide include dry detention basins, wet detention basins, low-impact development (LID) and DCIA minimization strategies, infiltration systems, and constructed wetlands. Conveyance design measures listed in this guide include street flow, intake capacity, storm sewer sizing, culvert hydraulics and sizing, open channel flow design, groundwater barriers, and stormwater swale systems. Stormwater infiltration measures listed in this guide include infiltration basins, bioretention systems, infiltration trenches, soil quality restoration, and native landscaping.
(B) Stormwater quality measures listed in this guide include wet detention basins, stormwater swale systems, bioretention systems, constructed wetlands, and native landscaping. Contractors and developers are required to stockpile and redistribute a minimum of four inches of topsoil as part of the final grading for the project or development. The guide contains figures and tables summarizing the appropriate use of each of the measures listed, as well as providing specifications and installation guidelines for each. The use of this guide is strongly encouraged when choosing management practices for post development stormwater. Other guides may be used to design outlet stabilization measures. Acceptable guidelines include the Denver Urban Drainage and Flood Control District publication Design of Low Tailwater Riprap Basins for Storm Sewer Pipe Outlets, the FHWA publication HEC-14, and other practices found in Iowa, Wisconsin, Nebraska, and Minnesota Department of Transportation design standards.
(Prior Code, § 6-21-9)