West Virginia Stabilized Construction Entrance BMP
Bordered on the east by the Blue Ridge Mountains in the Appalachian range, the state of West Virginia is filled with natural beauty. With a forest-lined coast, Summerville Lake is the largest of over one hundred reservoirs that are stocked with fish and provide water and recreation to the state's 1.8 million residents.
West Virginia DEP Stormwater Permits
To protect the state's natural resources, the West Virginia Department of Environmental Protection (WV DEP) administers the National Pollutant Discharge Elimination System (NPDES) Permit Program established by the Clean Water Act. The program requires all operators to obtain a permit before draining or discharging into surface waters, including rivers, lakes, or storm drains.
All construction projects that disturb an area of one acre or greater are required to obtain a stormwater permit before beginning operations. The stormwater permit application process involves developing a Stormwater Pollution Prevention Plan (SWPPP). The SWPPP includes a description of potential pollution sources on the job site and outlines Best Management Practices (BMPs) to mitigate pollution and sedimentation.
The West Virginia DEP produces the Erosion and Sediment Control Best Management Practice Manual, which is designed to assist contractors and engineers in selecting BMPs and creating SWPPPs for each project. The Manual provides technical details and maintenance schedules for a wide range of BMPs and includes alternative techniques to consider when additional protections are needed.
Section 3.02 of the Manual provides details about the Stabilized Construction Entrance which is one the first BMPs to be installed on any project.
Stabilized Construction Entrance
Sediment deposited on paved roadways can be washed into storm drains and into rivers and lakes, causing damage to aquatic ecosystems. Contractors implement measures to prevent sediment and debris from tracking onto public rights-of-way. The stabilized construction entrance is designed to prevent sediment and debris from tracking off the job site on vehicle tires by creating a cleaning area for tires as vehicles leave the site. The traditional method for creating a stabilized construction entrance and reducing sediment transport is to install a stone-stabilized pad.
A typical stone-stabilized pad is described in the Manual, along with information on maintaining the entrance throughout the project. The stabilized construction entrance pad is installed by excavating a minimum of 70’ in length, 10’ in width, and at least 6” deep where vehicles will exit the job site onto a paved roadway. The area is lined with a geotextile fabric and filled in with course aggregate between 4” and 6” in size. The area should have proper drainage to prevent sediment from flowing onto the roadway, and a sediment trap may be necessary to capture runoff.
These traditional stone stabilized pads will require maintenance as the job progresses. As rocks become compacted and filled with sediment, they can no longer effectively agitate vehicle tires. Maintaining the entrance involves top dressing the stone pad with additional aggregate to restore performance. The entrance should be inspected daily, but may be inspected weekly at a minimum, and after every rain event that is greater than 0.5 inches.
If the stone-stabilized pad is not adequately preventing vehicle trackout and sediment from entering the roadways, a wheel-washing station may be installed. The washing station must be over a stone and drain into an appropriate sediment trap to avoid draining out of the site.
Regardless of which BMP is chosen to prevent vehicle tracking, any sediment deposited in the roadway must be removed immediately. The roads can be cleaned using a sweeper, vacuum, or manually, but operators should not introduce water to clean the streets.
If the stone-stabilized pad is not adequately preventing vehicle trackout and sediment from entering the roadways, a wheel-washing station may be installed. The washing station must be over a stone and drain into an appropriate sediment trap to avoid draining out of the site.
Regardless of which BMP is chosen to prevent vehicle tracking, any sediment deposited in the roadway must be removed immediately. The roads can be cleaned using a sweeper, vacuum, or manually, but operators should not introduce water to clean the streets.
FODS Reusable Stabilized Construction Entrance System
The FODS Trackout Control Mats are an effective, reusable BMP designed to address the challenges associated with traditional construction entrance BMPs. The system consists of a single-layer HDPE mat with pyramid-shaped structures formed on its surface. The points of the pyramids agitate and flex vehicle tires and allow trapped debris to break loose and fall to the base of the mat.
Compared to traditional rock entrances, the FODS system will not degrade after heavy traffic. When an effective trackout control solution is needed, FODS can be installed without introducing the water and power requirements that would be required with a wheel wash station. The system can also be relocated and reused throughout each phase of the project, offering significant savings to contractors over the product's 10+ year service life.
The system is highly effective at removing sediment from vehicle tires, and has been demonstrated to reduce street sweeping by 59% on high-volume sites. Because the system is more effective than traditional aggregate stabilized entrances, a 5 mat layout (35’ in length) is commonly used as an alternative for 70’ stone stabilized pad construction entrances.
Vehicle tires drive on the tops of the pyramids, and the system can hold up to 2.5” of sediment at the base of the pyramids before coming into contact with vehicle tires. Maintenance of the FODS Trackout Control Mats is completed by sweeping the debris off of the mats. Sweeping is most commonly performed using a skid steer with a broom attachment, but can also be completed manually using a FODS shovel.
Additional Resources:
West Virginia DEP Stormwater Program