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 is the Delaware River, the state's namesake, which 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 land.

Economically, Delaware became a hub for manufacturing and industrial growth after World War II. As environmental regulations developed, industrial sites and construction managers adopted best practices to protect water quality and local ecosystems. Today, residents, businesses, operators, and the state work together to set standards that keep Delaware's waterways clean.

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 minimize pollutants entering the watershed. It created 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 Best Management Practices (BMPs) to minimize sediment and pollutant discharges in accordance with state water quality standards.

In 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 site that disturbs one acre or more must obtain NPDES stormwater permit coverage. Most construction projects can obtain coverage under the Construction General Permit (CGP) by submitting a Notice of Intent (NOI) along with site planning documentation, including a Stormwater Pollution Prevention Plan (SWPPP).

2026 NPDES Construction General Permit Update

DNREC reauthorized the Delaware NPDES Construction General Permit (CGP) effective March 11, 2026. The previous permit was first issued as a stand-alone permit in March 2021. The 2026 reauthorization includes several significant updates:

Clarified NOI and NOT requirements and on-site documentation procedures
Updated dust control, soil stabilization, inlet protection, sediment basin design, and dewatering controls to align with current regulatory standards
Reorganized pollution prevention measures to align with the 2022 federal CGP
Updated waste management and dumpster-emptying practices
Added an allowance to limit new permit coverage for permittees who fail to comply

The revised 2026 Delaware NPDES CGP and supporting Fact Sheet are available through DNREC's website.

The SWPPP and BMP Requirements

A SWPPP is a document that identifies all potential sources of pollution on the job site and specifies which techniques or measures will be used to contain those pollutants. These measures are called Best Management Practices (BMPs), and multiple BMPs are often used in combination to address a single pollution source.

DNREC publishes the Delaware Erosion and Sediment Control Handbook to guide contractors and engineers through the SWPPP planning process. The handbook was most recently updated effective January 2026. Stormwater Management plans submitted for approval on or after January 1, 2026 must include standard details bearing the "Effective January 2026" notation. The updated handbook aligns BMP standards with the 2026 CGP and the 2022 federal NPDES requirements, with revised requirements for inlet protection on all inlets receiving runoff from disturbed areas that have not achieved final stabilization.

Stabilized Construction Entrance (SCE) BMP Details

A stabilized construction entrance is typically one of the first practices an operator installs before other construction activities begin. It stabilizes heavily trafficked ingress and egress points and is designed to minimize sediment tracking by vehicles and equipment leaving the site onto public roadways. This BMP is installed at every access point on the site.

The SCE BMP works alongside 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 reaching storm drains.

Several options exist for designing and building an effective Stabilized Construction Entrance, each with its own maintenance requirements.

FODS Reusable Construction Entrance

The FODS Stabilized Construction Entrance System is a modular, reusable BMP designed to minimize construction site trackout. The system uses durable 12-foot by 7-foot mats formed into pyramids. The pyramid shape creates a rough surface that causes tire treads to spread open and release trapped debris.

Compared to traditional methods, FODS offers several advantages:

Performance: The FODS system does not degrade or compact over time and is up to 59% more effective than aggregate-based systems. Because the system uses no rock, there is no risk of stones entering roadways or being expelled from dual-tire vehicles.

Flexibility: FODS can be installed on any substrate and requires no power or water to operate. A 1x5T configuration (35 feet extended) is commonly used to replace a 70-foot rock entrance while providing a wide turning radius for exiting traffic.

Efficiency: The system can be deployed in as little as 30 minutes, and mats can be relocated and reused as needed across projects.

Cost savings: Mats are designed to last 10 or more years, eliminating recurring material costs associated with aggregate entrances.