Delaware Stabilized Construction Entrance BMP
Delaware is home to dozens of rivers and hundreds of smaller streams and tributaries that collectively drain stormwater across the state. The largest of Delaware’s rivers is also the namesake of the state: the Delaware River. The Delaware River drains approximately 13,500 square miles across Delaware, New Jersey, New York, and Pennsylvania. Much of the upper watershed remains forested, while lower reaches include urban and agricultural development. The Delaware River’s rich history consists of the transportation of wine, support for industrial development, and strategic efforts during the American Revolutionary War.
Economically, Delaware became a hub for manufacturing and industrial growth after World War II. As regulations developed, industrial sites and construction managers worked to bring best practices to the state to protect water quality and local ecosystems. Residents, businesses, operators, and the government work together to set standards and guidelines to protect water quality.
Delaware Department of Natural Resources and Environmental Control (DNREC) NPDES Permits
The Clean Water Act (CWA) of 1972 established laws and guidelines for industries and construction projects to mitigate pollutants introduced into the watershed. The Act established the National Pollutant Discharge Elimination System (NPDES) Permit Program, which regulates all discharges into the nation’s surface waters. The program requires operators to implement controls and BMPs to minimize sediment and pollutant discharges in accordance with state water quality standards.
In the state of Delaware, the Department of Natural Resources and Environmental Control (DNREC) administers the NPDES Permit Program. Operators of industrial, municipal, and construction sites must obtain permit coverage before beginning activities. Any construction sites that disturb an area of one acre or more must obtain NPDES stormwater permit coverage. Many construction projects can get coverage under the Construction General Permit (CGP) by submitting a Notice of Intent (NOI) along with site planning documentation, including a Storm Water Pollution Prevention Plan (SWPPP).
A SWPPP is a document that specifies all potential sources of pollution on the job site and indicates which techniques or measures will be taken to contain the pollutants on site. These measures are called Best Management Practices (BMPs), and in many cases, BMPs are used in combination to address a single pollution source.
The DNREC creates the Delaware Erosion and Sediment Control Handbook to assist contractors and engineers in the SWPPP planning and development process. This handbook includes standard devices and methods used to prevent the site from negatively affecting the storm water, including soil testing, dust control, mulching, and stabilized construction entrances.
Stabilized Construction Entrance (SCE) BMP Details
A construction entrance is usually one of the first practices implemented by an operator before other construction activities begin. Construction entrances stabilize the heavily trafficked ingress/egress points and are designed to minimize off-site tracking by vehicles and equipment exiting the site onto public roadways. This BMP is installed at every access point on the site to reduce and contain sediment sources.
The construction entrance (SCE) BMP is used in conjunction with other BMPs, such as daily street sweeping and sediment basins, to capture runoff. Street sweeping or scraping is conducted regularly and after every rain event to ensure sediment and debris are captured before entering storm drains.
There are several options for designing and building an effective Stabilized Construction Entrance, and each has its own maintenance routine that must be observed.
FODS Reusable Construction Entrance
The FODS Stabilized Construction Entrance System is a modular, reusable BMP designed to minimize construction site track out. The system is comprised of durable 12’ wide by 7’ long matting, which is formed into pyramids. The pyramids create a rough surface, which causes tire treads to spread open and release trapped debris.
Compared to traditional techniques, FODS offers several benefits to site operators. The FODS system does not degrade or become compacted over time and is up to 59% more effective than aggregate-based systems. FODS can be installed on any substrate and do not require power or water to operate. Because the system does not use rock, there is no risk of stones entering the roadways or being expelled from dual-tire vehicles.
Because the system is more effective than rock, the mats are well-suited for compact work environments. A 1x5T mat configuration (35’ extended) is commonly used to replace a 70’ rock entrance while providing a wide turning radius for exiting traffic. The mats offer significant savings for contractors, as they can be reused for 10+ years, eliminating the cost of construction entrance materials. FODS can be installed in as little as 30 minutes and can be anchored to dirt or on concrete and asphalt in urban settings.
The system can be deployed in as little as 30 minutes, allowing contractors to relocate and reuse it as needed on each project. The mats are designed to be reused on multiple projects throughout their 10+ year lifespan.