BMPs and Detention Ponds

Best Management Practices (BMPs) and Detention Ponds

Structural Best Management Practices, also known as BMPs, help control the flow of stormwater. BMPs reduce downstream flooding, provide natural filtration to reduce pollutant levels, and improve the overall health of the environment. DWR inspects all BMPs to ensure they are properly maintained. Examples of some common BMPs are below. Click on the BMP types below to view the Operations & Maintenance Guidance Documents.

In 2019 the Gwinnett County Phase I Large MS4 NPDES Permit required the County to apply new Stormwater Performance Standards for New Development and Redevelopment on or before December 10, 2020. The new Stormwater Performance Standards requires that final design of a construction project includes retention of the first 1.0 inch of rainfall on site. Because of this requirement, an update to the Gwinnett County Stormwater Management Manual (GCSMM) was necessary. In addition to this change, the GCSMM also includes addresses other minor changes. The Gwinnett County Board of Commissioners adopted Version 2.0 of the GCSMM on 10/6/2020, and it will be effective 12/10/2020.

Contractors must abide by the Gwinnett County Stormwater Management Manual.

Stormwater Management Manual Version 1, in effect until December 10, 2020
Stormwater Management Manual (After December 10, 2020)
HOA Contractor's List

For questions about maintenance of BMP's and Detention Ponds, contact: DWRstormwaterBMP@gwinnettcounty.com

Detention ponds

Detention ponds are designed to collect stormwater and pollutants and prevent downstream flooding. Stormwater runoff is transported to ponds by overland flow, ditches, swales, and underground pipes. While the water is in the pond, pollutants and sediment settle to the bottom. The cleaner water then leaves the pond gradually through an outfall structure, potentially discharging to a stream.

If there is a detention pond on your property, you (or your homeowners association) are responsible for maintenance. Preventative maintenance, like mowing around the pond and removing trash and excessive vegetation, prevents costly structural repairs and inspection violations. It also minimizes downstream environmental damage.

Failure to maintain your detention pond will result in non-compliance, beginning with a Notice-To-Comply letter and continued enforcement through the BMP Enforcement Response Plan. Continued lack of maintenance will result in the detention pond not functioning correctly and ultimately failing, which increases repair costs. Eventually the lack of maintenance could result in flooding on your property or downstream of your property.

Should you have questions or need assistance, the Department of Water Resources will work with you to establish a Plan of Action to help you achieve positive results on the maintenance of your BMP.

Green Infrastructure – How It Works

Bioretention	Wetlands	Bioslope
Dry Enhanced Swale	Infiltration Practice	Pervious Pavement
Stormwater Conveyance	Sand Filter	Gravel Wetland