Minimum Control Measure #5: Post-Construction Runoff Control

Bioswales are a structural BMP that can help mitigate the effects of stormwater once a site has been developed. 

Post-Construction Runoff Control is one of the six (6) Minimum Control Measures (MCM) required under the Small MS4 program*.  The goal of the Post-Construction Runoff Control MCM is to avoid increased stormwater runoff problems and increased non-point source pollution that often accompanies the development of land and associated increase in impervious surfaces.    Six (6) best management practices (BMPs) are required under this MCM.

Under Chapter 102, Erosion and Sediment (E&S) Control, County Conservation Districts and/or DEP must issue a permit for earth disturbance activities greater than 1 acre.  If the small MS4 permittee elects to use their participation in the Chapter 102 program as a Qualifying Local Program (QLP)  under their MS4 permit requirements, then MCM #5 BMPs 1 -3 are automatically accounted for. 

BMP #1 – Enact, implement, and enforce an ordinance or other regulatory mechanism to address post-construction stormwater runoff from new development and redevelopment projects, as well as sanctions and penalties associated with non-compliance.

BMP #2 – Develop and implement measures to encourage and expand the use of Low Impact Development (LID) in new development and redevelopment. Measures should also be included to encourage retrofitting LID into existing development.

BMP #3 – Ensure adequate operation and maintenance (O&M) of all post-construction stormwater management BMPs installed at all development ore redevelopment projects. An inventory of all PCSM BMPs shall be developed or updated as development projects are reviewed, approved, and constructed. Pollution can still result from construction sites after construction is finished; PCSM ensures this is minimized. Please check your local ordinances for O&M for BMPs for sites that are less than one acre.

What is a Post Construction Stormwater BMP (PCM BMP)?

PCM BMPs are practices that are put in place to prevent and mitigate stormwater runoff after the site is developed.  PCM BMPs include non-structural and structural BMPs.  Non-structural BMPs include practices that  aim to avoid and/or minimize damages associated with stormwater volumes and runoff from development.  Structural BMPs are engineered systems that are designed to mitigate the impacts of stormwater.

Examples of Non-Structural BMPs

Examples of Structural BMPs

Explore the links below to learn more about MCM #5, Post Construction Stormwater Best Management Practices, view educational webinars, and more. 

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