Construction Site Stormwater Runoff Control & Post-Construction Stormwater Management
 

Construction Activities:
 
  Uncontrolled stormwater runoff from construction sites can significantly impact rivers, lakes and estuaries. Sediment in waterbodies from construction sites can reduce the amount of sunlight reaching aquatic plants, clog fish gills, smother aquatic habitat and spawning areas, and impede navigation.
 
  Phase II MS4s are required to develop a program to reduce pollutants in stormwater runoff to the MS4 for construction sites disturbing one or more acres. This primarily includes developing:
  • An ordinance,
  • Requirements to implement erosion and sediment control BMPs,
  • Requirements to control other waste at the construction site,
  • Procedures for reviewing construction site plans,
  • Procedures to receive and consider information submitted by the public, and
  • Procedures for inspections and enforcement of stormwater requirements at construction sites.
 
  Mesa County’s requirements are in the Stormwater Management Manual
 

Post-Construction Activties:
 
  For the past two decades the rate of land development across the country has been more than two times greater than the rate of population growth. If unchecked, the increased impervious surface associated with this development will increase stormwater volume and degrade water quality, which can harm lakes, rivers, streams, and coastal areas.
 
  The best way to mitigate stormwater impacts from new developments is to use practices to treat, store, and infiltrate runoff onsite before it can affect water bodies downstream. Innovative site designs that reduce imperviousness and smaller-scale low impact development practices dispersed throughout a site are excellent ways to achieve the goals of reducing flows and improving water quality.
 
  Phase II MS4s are required to address post-construction stormwater runoff from new development and redevelopments that disturb one or more acres. This primarily includes developing:
  • Strategies to implement a combination of structural and non-structural BMPs,
  • An ordinance to address post-construction runoff, and
  • A program to ensure adequate long-term operation and maintenance of BMPs.
 
  Mesa County’s requirements are in the Stormwater Management Manual