Storm Water Program > Best Management Practices > Post Construction Program:
Best Management
Practices
Post-construction
storm water management in areas undergoing new development or redevelopment
is necessary because runoff from these areas has been shown to significantly
effect receiving waterbodies. As runoff flows over areas altered by development,
it picks up harmful sediment and chemicals such as oil and grease, pesticides,
heavy metals, and nutrients. These pollutants often become suspended in
runoff and are carried to receiving waters. Also of concern is that post
construction runoff quantities may be increased, delivering more water
to the waterbody during storms. Increased impervious surfaces interrupt
the natural cycle of gradual percolation of water through vegetation and
soil and can lead to streambank scouring and downstream flooding, which
often lead to a loss of aquatic life and damage to property. Studies indicate
that the most cost effective approach to storm water quality management
is prior planning and design for the minimization of pollutants in post-construction
storm water discharges.
To meet the requirements of this minimum control measure, the operator of a regulated small MS4 will need to at a minimum:
-
Develop and implement strategies which include a combination of structural and/or nonstructural BMPs;
- Develop an ordinance or other regulatory mechanism requiring the implementation of post-construction runoff controls to the extent allowable under State or local law;
- Ensure adequate long-term operation and maintenance of controls;
- Determine appropriate best management practices (BMPs) and measurable goals for this minimum control measure.
Recommendations for developing a successful post construction runoff control program:
- Select BMPs that are appropriate for the local community, minimize water quality impacts, and attempt to maintain predevelopment runoff conditions;
- Assess existing ordinances, policies, and programs that address storm water runoff quality; Participate in watershed planning efforts;
- Provide opportunities for public participation.
Menu
of BMPs: Post Construction Runoff Control
Post
Construction Runoff Control Model Ordinance (Center of Watershed Protection)
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EPA Post Construction
Runoff Control fact sheet
DEM Nonpoint Source Program Draft Model Storm Water Control Ordinance
Maryland Storm Water Design Manual
New York State Storm Water Management Design Manual