Virginia Temporary Stone Construction Entrance BMP

The state of Virginia is home to a variety of natural inland attractions including 544 miles of the Appalachian Trail, the stunning Blue Ridge mountains, and the 50,000 acre John H. Kerr Reservoir. The eastern side of the state borders the Atlantic Ocean and includes over 7,000 miles of shoreline between the ocean and the Chesapeake Bay. Virginia places a high value on preserving the quality of the vital water resources which support the local aquatic ecosystems throughout the state.

Virginia Department of Environmental Quality & VSMP Authorities

Throughout the state of Virginia, the Department of Environmental Quality administered the National Pollution Discharge Elimination System (NPDES) permit program as prescribed by the Clean Water Act. NPDES Stormwater permits are required for a variety of activities to regulate water dischargers into surface waters. The permit program requires that operators of industrial sites and construction sites mitigate sedimentation and pollution on-site before the contaminants reach the surface water and aquatic ecosystems.

All construction sites that disturb an area of one acre or greater are regulated under the program and are required to obtain permit authorization. To obtain authorization, operators must create and submit a Stormwater Pollution Prevention Plan (SWPPP) along with a Notice of Intent (NOI). The SWPPP outlines all pollution sources on the project, and defines techniques and strategies that will be used to eliminate or mitigate harmful effects. These techniques are called Best Management Practices or BMPs. The DEQ issues an Erosion and Sediment Control Handbook to summarize common techniques used for each source of pollution.

The DEQ or a local authority, called a VA Stormwater Management Program (VSMP) authority, reviews the SWPPP plans as part of the NPDES stormwater application process. The DEQ or VSMP is responsible to enforce compliance with the stormwater regulation, and will regularly inspect the site to monitor the performance of various techniques and BMPs to ensure compliance with permit requirements.

Erosion and Sediment Control Handbook - Stabilized Construction Entrance

The Virginia DEQ publishes an Erosion and Sediment Control Handbook which is designed to assist contractors and industrial operators as they create their stormwater permit applications. The handbook outlines the common BMPs which are used throughout the state and includes specifications, application recommendations and maintenance schedules. One of the first BMPs to be installed on construction projects is the Stabilized Construction Entrance which is used to fulfill the requirements in the Virginia Code 9VAC25-840-40 Minimum standards.

The standards state:

17. Where construction vehicle access routes intersect paved or public roads, provisions shall be made to minimize the transport of sediment by vehicular tracking onto the paved surface. Where sediment is transported onto a paved or public road surface, the road surface shall be cleaned thoroughly at the end of each day. Sediment shall be removed from the roads by shoveling or sweeping and transported to a sediment control disposal area. Street washing shall be allowed only after sediment is removed in this manner. This provision shall apply to individual development lots as well as to larger land-disturbing activities.

Temporary Stone Stabilized Construction Entrance

The traditional technique used to fulfill the requirements for the Stabilized Construction Entrance is the use of a Temporary Stone Construction Entrance. A stone construction entrance consists of a stone driveway or pad at least 6” inches deep which is underlaid with a woven filter fabric. The stone collects debris as vehicles leave the site and prevents sediment and debris from becoming deposited onto paved roadways which will be washed into storm drains.

The handbook specifies that #1 VDOT coarse aggregate (2” and 3” stones) are used on construction entrances. The minimum dimensions of the stone construction entrance are 70 feet in length, 12 feet in width and 6 inches in depth. To ensure all exiting traffic will use the entrance, the width should span the entire access way. When installing the entrance, contractors should excavate a minimum of 3” down to prepare the substrate for the fabric material.

A construction entrance should be installed at all points of vehicular ingress and egress, and all construction traffic should be directed to use the entrances to prevent vehicle tracking and mud transport onto paved surfaces. This technique is only effective if all vehicles are exiting through the construction exit points.

As the construction project progresses, the entrance must be maintained to ensure effectiveness. When the rock entrance is no longer effective at mitigating sediment tracking onto roadways, the entrance must be refreshed or top dressed with additional rock. Alternatively, the rock can be washed and reused provided that proper drainage is used to prevent sediment from entering storm drains.

Rock and Wash Rack

If the stone stabilized entrance is not sufficient to mitigate trackout on the project, a wash rack may be installed. A wash rack station uses pressurized water to clean debris from vehicle tires. Some wash rack stations are placed on the construction exit as a supplemental technique, while other systems are designed to be used as a stand-alone solution for vehicle trackout. Contractors implementing a wash rack must ensure that there is proper drainage of sediment laden water. In most cases, sediment traps or sediment basins are used to capture debris to prevent pollution from entering storm drains.

FODS Reusable Stabilized Construction Entrance System

FODS Trackout Control System is an effective technique to minimize vehicular sediment tracking on construction and industrial sites. The system consists of a single layer of HDPE matting which is formed into pyramid shaped features on the surface. The pyramids work to flex vehicle tire treads allowing trapped debris to break loose. The mats are each 12’ wide x 7’ in the direction of travel. The system is modular and can be installed to fit the specifications of each project.

The system can be installed over any substrate including asphalt, concrete or directly on grade. The 30 minute installation process is well suited for phased projects including highway, pipeline, or commercial jobs because the construction entrance can be relocated during each phase of the project and reused again and again. Compared to traditional techniques, the FODS system has demonstrated a reduction in street sweeping by 59% on high volume sites, and is often recommended for sites that require a more effective sediment tracking control than traditional methods can provide.

The FODS Trackout Control System maintains effective performance over the life of the product, and is not degraded by heavy traffic or rain events. The mats require maintenance when sediment builds between the pyramids. Maintaining the system involves cleaning the mats; cleaning is usually performed with a skid steer using a broom attachment or manually using a FODS shovel. The mats are designed to be used as a stand-alone BMP to mitigate vehicle tracking in place of a traditional stone stabilized construction entrance. In most cases, a 35’ long 1x5 configuration is used as a replacement for a 70’ stone construction entrance.