Bioretention Basin Health: Effective Stormwater Control Measure
Bioretention basin in Raleigh, North Carolina restored to proper health and function as an effective Stormwater Control Measure.
A bioretention basin is a type of stormwater control measure (SCM) that is effective at removing a variety of pollutants from stormwater runoff and helps manage local water levels during rain events. A properly functioning bioretention is able to remove both suspended solids and nutrients and bacteria from stormwater runoff in order to keep these pollutants from reaching nearby lakes and streams. Stormwater is filtered through the system biomedia (soil-based material) before reaching underdrains to be transported downstream.
Unfortunately, the functioning of the stormwater control measure can become compromised if it is not maintained properly. A bioretention basin that does not drain properly can lead to poor sediment and pollutant filtration, flooding, fines, and becoming a mosquito-infested swamp. Leaks in outlets, inlets, and risers can lead to dangerous sinkholes.
Recently, the Dragonfly stormwater management experts were consulted on an overgrown and neglected Raleigh bioretention basin. Our assessment found that the system suffered from poor infiltration and draining due to the accumulation of roots, sediment, and organic debris on top of the bioretention and due to underdrain pipes wrapped in fabric that had become clogged.
The neglected, overgrown system.
Bioretention Basin Restoration Process:
The Dragonfly crew removed the trees within the bioretention and disposed of them off-site. They also excavated and disposed of the poor quality biomedia and sand off-site.
Once the degraded biomedia and sand were removed, the crew removed all three of the old, clogged underdrains in this stormwater control measure.
A thin layer of old biomedia and clay were brought in to raise the elevation of the bioretention basin bottom. The crew utilized a roller to ensure proper compaction of materials.
The crew continued to check elevation levels for proper grading throughout the process.
Separation fabric was installed on the bottom and sides of the system. A layer of crushed stone is placed over the fabric, followed by the new perforated underdrains, and then a layer of finer crushed stone.
Next, a layer of clean washed sand was graded throughout the bioretention basin.
Following the sand was a 24-inch layer of bioretention media. All of these layers help ensure appropriate pollutant filtration.
To complete the bioretention basin, sod was installed over the graded biomedia. This vegetation assists with pollutant and runoff absorption, along with desired infiltration rates.
Before and after photo of the restored Raleigh bioretention basin.
The neglected, overgrown system has been converted into a healthy, compliant bioretention basin. Proper specialized stormwater maintenance will keep this system healthy and functioning. Specialized crews possess the knowledge and experience necessary to effectively maintain stormwater control measures such as this and keep potential issues at bay. Dragonfly's stormwater maintenance crews provide detailed monthly reports to alert clients to any issues that may need to be addressed before they worsen and repairs become more costly. Please contact us to learn how we can help restore and maintain your stormwater system.
Learn More!
Read our expert tips for proper bioretention maintenance to keep your system healthy. Learn about the process a system goes through from construction basin to annual inspection, including the benefits of specialized stormwater maintenance! Read about utilizing Integrated Pest Management as part of a comprehensive lake, pond, or stormwater maintenance plan.
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Dragonfly Pond Works is a lake, pond, and stormwater management company. We provide our stormwater services, bioretention basin restoration, and more throughout North Carolina, in Raleigh, Durham, Charlotte, Cary, and Wilmington. Our pond and lake maintenance services can be found throughout Florida, in Tampa, St. Petersburg, Naples, Sarasota, Fort Myers, and Orlando. We also provide our services in Myrtle Beach, Charleston, Columbia, South Carolina and Atlanta Georgia. We strive to develop long-term relationships based on quality work, timely service, cost-efficiency, and of course, trust.