Measure 5b: Establish strategies that include BMPs
 appropriate for the MS4

“Develop and implement strategies that include a combination of structural and/or non-structural BMPs. Ensure adequate long-term operation and maintenance of structural BMPs. Require annual inspection reports of permitted structural BMPs performed by a qualified professional.”

These areas already comply with Phase II post-construction stormwater requirements:

• Water supply watersheds (WS-I through WS-IV)
• HQW and ORW watersheds
• Neuse River Basin stormwater program areas
• Tar-Pamlico River Basin stormwater program areas
• Randleman Lake water supply watershed

Areas within Phase II jurisdictions will be required to meet the post-construction stormwater requirements laid out in the permit. Similar to other state stormwater programs, the Phase II permit sets thresholds for low and high density developments. Low density developments are allowed without a structural BMP to control stormwater. High density developments do require a structural BMP. The requirements are summarized in the table below.

Both high and low density developments must:

• Keep all built-upon areas at least 30 feet landward of perennial and intermittent surface waters (USGS and Soil Survey maps).
• Have deed restrictions and protective covenants to ensure that future development activities maintain the development (or redevelopment) consistent with the approved plans.

Phase II local governments may develop comprehensive watershed protection plans to meet part, or all of the requirements for post-construction stormwater.

To assist Phase II local governments in implementing the post-construction stormwater program, DWQ has developed a draft Stormwater BMP Manual. Phase II local governments have the option of adopting this manual as their own, modifying it to suit their needs, or creating their own BMP manual. The DWQ Stormwater BMP Manual is a lengthy document that covers the siting, design and construction of the following structural BMPs:

• Stormwater wetlands
• Bioretention
• Wet detention basin
• Dry extended detention basin
• Grass swale
• Filter strip
• Infiltration systems
• Manufactured BMPs
• Buffer
• Permeable pavement
• Rooftop runoff management
• Sand filter

One of the biggest new challenges created under the post-construction stormwater requirement is the requirement for ongoing maintenance of structural stormwater BMPs. Phase II local governments will need to have a BMP operation and maintenance ordinance to establish this requirement and set up penalties if BMPs are not operated and maintained appropriately. EPA’s model local ordinances on BMP maintenance web site can provide guidance on this.

Some other links that can assist Phase II local governments on BMP operation and maintenance are:

• Greensboro Stormwater Operation and Maintenance Manual
• The Florida Stormwater, Erosion and Sedimentation Inspector’s Manual
• Maintaining Your BMP: A Guidebook for Private Owners and Operators in Northern Virginia
• The Center for Watershed Protection Publications web site will soon include a Stormwater Maintenance Manual that is currently being developed. The manual will include a set of web-based tools to help communities develop a state-of the art maintenance program. Stormwater practitioners will be able to download readily usable maintenance forms, updated maintenance cost data, ordinances, and other key elements of a good program.