Minimum Control Measure #5
Post-construction Stormwater Management in New Development and Redevelopment (PCSM)
Program Objectives
The development or redevelopment of land areas can significantly affect the quantity and quality of stormwater runoff. Changing the topography or replacing natural ground cover with impervious surfaces can increase the volume of runoff and significantly increase peak runoff rates. The increase in volume and peak runoff rates can accelerate erosion rates in local stream channels and increase the risk of flooding in adjacent low-lying areas. Changes in land use can lead to the introduction of new pollutants (such as gasoline, oil, grease, fertilizer, household chemicals, etc.) to local water bodies. Left unchecked these pollutants can migrate into the County’s municipal separate storm sewer system (MS4) and eventually into local receiving waters such as Plum Creek and Cherry Creek and their tributaries, reducing the receiving water quality.
The objectives of Douglas County’s Post-Construction Stormwater Management (PCSM) program center on the effective design, installation, operation, and maintenance of post-construction water quality BMPs. The general objectives of the PCSM program include the following:
Meet the post-construction water quality requirements for coverage under the Colorado Discharge Permit System (CDPS) General Permit for the Cherry Creek Reservoir Basin.
Meet the post-construction water quality requirements of both the Cherry Creek Reservoir Control Regulation No. 72 and the Chatfield Reservoir Control Regulation No. 73, respectively.
Promote proper and consistent design, review, installation, inspection, and maintenance of water quality BMPs at newly developed or redeveloped sites throughout unincorporated portions of the County.
To the maximum extent practicable, control the discharge of stormwater and reduce the discharge of pollutants from newly developed or redeveloped sites.
To the maximum extent practicable, improve the quality of stormwater as it moves through the County’s MS4.
Educate local designers, contractors, water quality BMP owners (private owners, businesses, homeowners associations, etc.) on the importance of the proper design, installation, operation, and maintenance of water quality BMPs.
DRAINAGE MANUAL - available for purchase through the Engineering Division.
Drainage Manual Update - Douglas County is involved in a cooperative effort to revise and update the Douglas County Storm Drainage Design and Technical Criteria Manual and criteria manuals of other participating local governments. Communities and agencies involved in the project are Arapahoe County, Douglas County, the City of Centennial, the Town of Castle Rock, the City of Lone Tree, and the Urban Drainage and Flood Control District.