BMPs and Detention Ponds
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.
- Bioretention Area
- Dry Detention Fact Sheet
- Dry Detention Checklist
- Dry Extended Detention Basin
- Dry/Wet Enhanced Swale
- Gravity Oil/Grit Separators
- Proprietary System (Water Quality Device)
- Sand Filter
- Stormwater Pond
- Stormwater Wetlands
- Underground Detention
- Vegetated Filter Strip
- Detention Pond Informational Folder
Contractors must abide by the Gwinnett County Stormwater Management Manual.
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.
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. There are also several homeowner benefits to a well-maintained detention pond: beautification of your property, increased diversity of flora and fauna, and improved air quality.
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 and could cause sediment to be released into the storm sewer system. 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.