Public Works Department

In 2008 Rapid City made a significant change in how stormwater runoff is managed. In particular, how we manage pollutants commonly found in stormwater runoff. As an obligation of the Clean Water Act, the Environmental Protection Agency required Rapid City, along with hundreds of other communities across the country, to develop stormwater programs that reduced the amount of pollutants which enter nearby streams and lakes from the storm drainage system. In our case this is predominantly Rapid Creek.

In response to this mandate a Stormwater Steering Committee was created in 2007 to help develop a stormwater management program. Two of the major focus areas of the stormwater program were the reduction of pollution from construction sites (erosion and sediment control) and the reduction of pollution from sites after they have been fully developed (employing post construction best management practices).

Perhaps the most significant source of stormwater pollution is sediment which leaves construction sites. In order to address this the City has instituted a new ordinance which requires erosion and sediment control practices be implemented on all construction sites. Prior to significant earth disturbing operations, an erosion and sediment control permit must be secured from the Growth Management Department. The permit will require the applicant to detail their operations and describe the erosion and sediment control practices they will be using to minimize pollution. Common practices include site stabilization, silt fence, inlet protection, wattles, vehicle tracking stations, dedicated concrete washout areas and silt traps.

Another significant source of pollution is found in the stormwater runoff from land that has been fully developed. With the addition of human activity comes the potential for pollution to be created. Pollutants like fertilizers from lawn care, hydrocarbons from automobiles, salt and sands from deicing operations and fecal matter from household pets eventually migrate into the storm drainage system and ultimately find their way into Rapid Creek. To reduce this the City developed another ordinance which requires measures be taken in the development or redevelopment of land to capture these pollutants before they enter the storm drainage system. Common practices would be the installation of devices which act to settle out pollutants. This would include constructed wetlands, retention ponds, detention ponds, grass swales, bioretention and porous landscape detention.

To aid in a better understanding of how these new changes will affect those in the construction and land development industry the City will be hosting a series of presentations and workshops in March of 2008. Invitations will be sent out as plans become finalized. In the meantime, you can learn more about the City’s Stormwater Management Program by visiting our website at www.rcgov.org. Here you can read a full description of the program focus areas along with associated ordinances, the stormwater quality design manual and other interesting information.

Robert Ellis, PE, PTOE
Public Works Director