Regional Stormwater Study
In 2004 Scott County was rated the fifteenth fastest growing county in the United States. The County’s population is anticipated to double within 30 years. The resulting increase in land values and speed of land development underscored the importance of evaluating the County’s capacity to provide the needed stormwater infrastructure to sustain further population increases. As areas develop, portions of the ground surface are covered with hard surfaces such as roofs and pavement. These impervious surfaces reduce the infiltration of precipitation increasing the potential for increased surface water runoff. With development, stormwater is also collected in street curbs, gutters, ditches and pipes. The combination of increased runoff and the efficient collection of runoff can lead to problems with water quality and flooding if left unmanaged. Typically, these issues are managed on a site by site basis with requirements for individual developments to build stormwater holding ponds or other facilities. However, there may be economies of scale or better ability to maintain facilities, if they are built to serve a larger area or more than one development.
The Scott WMO recognizes the potential efficiencies with regional ponds and the 2004 Comprehensive Water Resources Plan establishes policies to assess the potential for, and promote regional solutions. As part of implementing these policies, the Scott WMO hired BARR Engineering to conduct a regional stormwater planning study. This study will assist the WMO in identifying sites in the County that may provide opportunities for regional stormwater management for flood control. The study did not explicitly evaluate the potential of the regional ponding system to improve water quality, but the proposed ponds may also be utilized for water quality purposes. Ultimately, the identified areas could be listed for protection/acquisition as part of the 2030 Comprehensive Plan Update for Scott County. The project area includes the portions of the Sand Creek watershed located in Scott County, and the Southwestern watershed in the western portion of Scott County.
A final report for Sand Creek and Credit River is available below. Preliminary results show that there are numerous locations where regional facilities could be built without conflicting with existing regulations. However, there are a number of outstanding questions brought up by the Technical Advisory Committee for the WMO: such as how are you to fund construction, how do you get the water to the facilities, and over such a large area – which facilities do you start with? These are questions that the WMO will consider. In the mean time, it is anticipated that regional stormwater management where feasible, will be included as a potential public value incentive by the County in the 2030 Comprehensive Plan Update. The 2030 Comprehensive Plan was adopted March 24, 2009. This public value could be used to provide a density bonus to someone developing when they dedicate areas for regional ponding where considered feasible by the County, the WMO, or a township. This is being promoted because regional stormwater facilities, while being difficult to implement, do provide a public value and dedication of suitable areas saves the public acquisition dollars.
Sand Creek & Southwest Watersheds Regional Stormwater Technical Report
10/26/2007
Credit River Watershed Regional Stormwater Technical Report
2/2/2009