Arkansas Stabilized Construction Entrance
The Department of Environmental Quality administers the Clean Water Act in Arkansas. Construction sites that disturb one acre or more of land are required to obtain NPDES stormwater permit coverage. Contractors, MS4s, and Industrial sites each must obtain a permit from the DEQ. A Notice of Intent (NOI) is submitted before construction or operation begins. Most General NPDES Permits may be completed and submitted online through the DEQ ePortal site.
Arkansas ARR150000 NPDES Stormwater Permits
To obtain a Construction Stormwater Permit (ARR150000), contractors will submit a Stormwater Pollution Prevention Plan (SWPPP), an NOI, and the fee to the DEQ. The SWPPP contains a site-wide plan detailing Best Management Practices to mitigate stormwater pollution. One commonly required BMP is the use of a Stabilized Construction Exit at locations where vehicle tracking may occur. These entrances are designed to minimize the sediment-laden dirt tracked from the jobsite onto impermeable surfaces like asphalt. Polluted sediment on roadways will wash down stormdrains and enter protected rivers and streams.
ArDOT Stabilized Construction Exit Details
Appendix A.11 of the Erosion & Sediment Control Design & Construction Manual from The Arkansas Division of Environmental Quality (DEQ), within the Arkansas Department of Energy & Environment, administers the Clean Water Act, which provides design criteria for stabilized entrances—gravel or other surface material placed at construction site access points to reduce vehicle-tracked soil onto roads. The manual references Section 110 of the Standard Specifications for Highway Construction and the General NPDES (National Pollutant Discharge Elimination System) Construction Permit, both of which require minimizing off-site sediment tracking and preventing the movement of construction site soil onto public surfaces. Contractors are instructed to build a stabilized construction exit wherever traffic will be leaving the work zone directly onto a public road or other paved area. In addition to constructing stabilized exits, contractors must ensure that sediment tracked from the construction site is swept, collected, and removed so it does not enter storm drains. The frequency of sweeping must be sufficient to minimize off-site impacts on water bodies, including streams, lakes, and wetlands that may receive runoff.
An example of a traditional aggregate construction exit is provided in the manual. It features a 12’ wide, 50’ long gravel tracking pad using coarse aggregate (3” or larger). Filter cloth is placed under the aggregate. Periodic inspections check whether the stone tracking pad is functioning properly. Maintenance is needed when dirt builds up on the rock or the tracking pad becomes compacted. To maintain the pad, mix or scrape the top rock layer, or top dress with additional crushed rock. Rain can increase maintenance needs.
FODS Trackout Control System
FODS Trackout Control System consists of a single layer of reusable mats made from composite materials. These construction exit mats are specifically designed to remove soil and small particles (sediment) from vehicle tires as they leave a job site. FODS serves as a modern construction entrance that is modular—meaning its parts can be connected or rearranged to fit different sites—and is also easy to install and maintain. The unique design of the mats helps trap more sediment and continues working well even after rain events, when mud or debris might be more prevalent.
A standard layout is a 1x5T, which provides a wide turning radius and 35’ of length. FODS are more effective than aggregate construction entrances, so this layout is used to replace a 70’ traditional rock entrance.
One advantage of FODS is its ability to be reused and relocated during various phases of a construction project. FODS mats are engineered for durability and are designed to last for over 10 years.
The pre-fabricated FODS trackout control mats can be installed without excavation and over a variety of substrates (base surfaces such as dirt, gravel, or asphalt). Maintenance is needed after sediment builds up to 2.5 inches between the pyramids on the mat. Instead of adding more rock as in traditional systems, the FODS system can be restored by cleaning with a street sweeper or a special FODS shovel.
Additional Resources:
ADOT Erosion & Sediment Control Design & Construction Manual