Vermont Stabilized Construction Access BMP
Vermont is the only landlocked state in New England, yet two essential bodies of water border it. Lake Champlain in the northwest region of the state is the sixth-largest body of fresh water in America and separates Vermont from New York State. This section of the state, known as the Champlain Valley, is known for its fertile land, which supports the state’s agricultural production. The Champlain Valley is part of the Saint Lawrence River drainage system, which is the primary drainage basin of the Great Lakes into the Gulf of Saint Lawrence, one of the largest estuaries in the world. The Connecticut River creates the natural eastern border of Vermont. Over 40% of Vermont’s stormwater drainage empties into the Connecticut River, which discharges into the Long Island Sound.
The Vermont Clean Water Initiative has reported that $194 million has been spent to begin restoring water quality throughout the state. This initiative continues to work to maintain the health of Vermont's water, ecology, environment, cities, and economy.
Vermont Department of Environmental Conservation (DEC) NPDES Stormwater Permits
To mitigate the effects of industrial and construction activities on the nation’s surface water sources, the federal government initiated the Clean Water Act, which established the National Pollutant Discharge Elimination System (NPDES) Permit Program. The Program establishes regulations on water discharges from municipal, industrial, and construction activities that could otherwise cause excessive sedimentation or pollution.
The Vermont Department of Environmental Conservation (DEC) administers the NPDES Permit Program which includes reviewing applications, issuing permits, and enforcing permit requirements. All operators of construction sites that disturb an area of one acre or more are required to obtain permit coverage. Most construction sites can obtain permit coverage under the Construction General Permit (CGP) 3-9020 by submitting a Notice of Intent (NOI) along with an Erosion Prevention and Sediment Control (EPSC) Plan.
The development of an EPSC Plan includes defining areas of disturbance and all potential pollution sources. The most common type of water pollution is sedimentation, which occurs when excessive soil is deposited into the streams and lakes. The EPSC Plan will outline the strategies and techniques to be used on-site to mitigate erosion and prevent pollutants from escaping the construction area. Best Management Practices or BMPs. A few of the effective measures that are necessary for a proper EPSC Plan are silt fences, sediment basins, rolled erosion control products (RECP), and Stabilized Construction Access.
Stabilized Construction Access BMP
Site entrances and exits receive high volumes of vehicle traffic, which can track sediment onto roadways and wash into storm drains. To prevent this sedimentation, a Stabilized Construction Access is installed to remove mud and sediment from vehicle tires before they exit the job site. A Stabilized Construction Access is usually one of the first practices an operator implements before other construction activities.
Construction access stabilizes access points and removes the majority of sediment from vehicle tires. The construction entrance must be appropriately maintained to remain effective. Depending on expected traffic volume, multiple or alternative BMPs may be used to stabilize the entrance. In addition to stabilizing entrances, operators use street sweeping and vacuuming to recover sediment tracked out of the job site.
Stabilized Rock Construction Exit BMP
The Vermont Standards and Specifications for Erosion Prevention and Sediment Control include details on an aggregate-stabilized pad, which is commonly used to stabilize construction site entrances.
The standards include considerations to ensure the entrance adequately prevents track out. In some cases, an aggregate pad may not be sufficient to remove the majority of the sediment. In these cases, supplemental or alternative BMPs may be used to remove mud from vehicle tires.
Wheel Wash Station BMp
The Standards mention a wheel wash station, which can be installed when additional cleaning is required. A wheel wash station consists of a wash rack laid over a raised structure or a gravel bed. Tires are washed either manually or using an automated system while vehicles are over the wash rack. When using a wash rack, all drainage must be intercepted and drained into a sediment trap or basin to prevent runoff from flowing off-site.
FODS Trackout Control System
The FODS Trackout Control System is an effective system for containing site trackout, which uses mechanical action on vehicle tires to remove debris. The modular system consists of a series of 12’ x 7’ HDPE matting, which is formed into pyramid-shaped structures on the surface. The pyramids deform and flex vehicle tires in multiple directions to dislodge sediment, rocks, and debris that is lodged between tire treads. FODS can be installed over existing substrates, including dirt, concrete, and asphalt.
The FODS Construction Entrance Mats are designed to be reused across multiple projects over the expected 10+ year service life. The mats can be easily relocated, significantly reducing costs on phased projects and across multiple projects. Installation, maintenance, and removal can be completed without the heavy equipment and a standard installation can be completed in under 30 minutes.
The 3”- tall pyramids can hold up to 2.5” of sediment, as the tires only contact the tips of the pyramids. When maintenance is required, the street sweeper or a skid steer with a broom attachment can be used to brush away sediment to restore performance. Manual cleaning can be completed with a FODS Shovel, which is designed to fit between rows of pyramids. Contractors can integrate maintenance during regular street sweeping to ensure the entrance is always compliant with permit requirements.
The FODS system is more effective than traditional Rock Construction exits and has been shown to reduce street sweeping by 59% in high-traffic-volume applications. Because the system is highly effective, FODS are commonly specified at 50% of the length of a stone-stabilized tracking pad to provide equal performance. Because no materials are consumed during the life of the project, FODS enables contractors to reduce costs on each project where the mats are used.
Additional Resources
Vermont DEC Construction Stormwater Discharge Permits
Vermont Standards and Specifications for Erosion Prevention and Sediment Control
Vermont Standards Excerpt - Part 5 - Stabilized Construction Access