Stormwater Pollution Prevention Plan Guide (SWPPP & BMPs)
In 1972, the Clean Water Act (CWA) was passed with the goal to “restore and maintain the chemical, physical, and biological integrity of the Nation's waters.” The CWA, which is a revision to the Federal Water Pollution Control Act of 1948, prohibits the discharge of pollutants into navigable waters, requires States to create processes and management practices to control sources of pollutants, and establishes funding for public waste treatment plants. Today, the Clean Water Act has achieved the original goal of eliminating the discharge of pollutants into navigable waters by 1985 and this Act is still the primary federal law protecting surface water in the United States.
National Pollutant Discharge Elimination System (NPDES): SWPPP Plans, & Construction General Permits
To achieve the goals of the Clean Water Act, the National Pollutant Discharge Elimination System (NPDES) was created to enable permitting, administration and enforcement of the requirements of the CWA. The National Pollutant Discharge Elimination System specifically regulates point sources of pollution.
Stormwater pollution point sources include municipal separate storm sewer systems (MS4s), construction sites, and industrial plants. These three types of point sources have specific permits which are created to address the pollution sources encountered in each environment. Typically, sites that are larger than five acres are required to obtain a stormwater permit to discharge water, however, some jurisdictions also require permits for sites as small as one acre.
In each state, the NPDES is administered either by the Federal Environmental Protection Agency (EPA) or is delegated to a local government department. Find the permitting authority in your jurisdiction.
Construction General Permits
The Construction General Permit (CGP) is the NPDES stormwater permit required for typical construction sites. The CGP is always required when construction sites disturb an area larger than five acres, and many jurisdictions require permits for sites that disturb one acre or more. Each CGP application must include a Storm Water Pollution Prevention Plan (SWPPP) which identifies potential sources of pollution and outlines the techniques that will be used to mitigate the pollution.
The SWPPP is comprehensive high-level overview of all practices and techniques that are used to mitigate pollution. The individual techniques implemented in the SWPPP are referred to as Best Management Practices (BMP) which are implemented to contain pollutants. Multiple BMPs may be included on the SWPPP for the same pollution source and may be designed to work either as a standalone solution or in conjunction with other BMPs.
What is a Stormwater Pollution Prevention Plan (SWPPP)?
Point sources can create significant pollution, so prevention measures are put in place to prevent pollution from entering surface waters. The NPDES permitting process involves identifying these pollution sources and choosing strategies to address these pollution sources. Specific pollution prevention measures and strategies are called Best Management Practices (BMP). The pollution sources and prevention measures are outlined in a document called a Stormwater Pollution Prevention Plan (SWPPP) which is submitted with the NPDES permit application.
What does a Construction SWPPP contain?
SWPPPs includes general, non-detailed outlines of pollution sources and indicates which BMPs will be used to prevent stormwater pollution. BMPs on the other hand generally provide information about applicability, implementation, effectiveness and any other pertinent details for the practical application of the pollution prevention mechanism. While many states and municipalities produce recommendations and guidelines, BMPs are tailored to the specific site they will be used on. The engineer will provide specifications for each BMP to ensure that the requirements of Construction General Permit are met.
A SWPPP will identify risks and specify which BMPs will be used for all potential pollution sources including:
- Isolation of jobsite materials from stormwater.
- Plan to protect trees and other natural features from polluted stormwater during construction.
- Containment of stormwater within the jobsite.
- Protecting storm drains from sediments.
- Erosion risks and prevention plan.
- Construction entrance to prevent trackout.
- Plan to clean roadways of debris that leaves the jobsite.
Click Here for and example of a SWPPP from the EPA website.
What is a BMP or Best Management Practice?
Compared to a SWPPP which is a high-level overview, a BMP provides a closer look at a specific pollution mitigation technique that will be used on the job site. A BMP will specify minimum standards when applicable for the technique to work properly. BMPs will state the goal of the technique and which usually correlates to a requirement specified by the EPA in the NPDES permit. Some goals involve multiple BMPs that work together to reduce pollution.
In the case of carryout or trackout control, the BMP will specify the minimum standards for a stabilized construction entrance/exit tracking pad. The standards will include the expected length, width depth, and coarseness for the aggregate used on a traditional vehicle tracking pad as well as drainage considerations. The BMP will also specify where to place the entrance/exit and when the BMP is applicable to the project. The BMP may specify appropriate alternatives with separate minimum standards.
Sediment and Trackout Control and Stabilized Construction Entrances/Exits
Trackout control is a goal that is usually addressed by two or three BMPs. In the CALTRANS handbook, for example, Trackout Control involves multiple BMPs such as TC-1 “Stabilized Construction Entrance/Exit”, and the TC-3 for “Entrance/Outlet Tire Wash” which can be implemented together to reduce sediment and erosion pollution. In addition, the SC-7, “Street Sweeping and Vacuuming” is referenced to be implemented as needed to maintain dust control and recover sediment that leaves the site before it can enter storm drains. Street sweeping is almost always required as a complementary BMP which addresses debris that is not contained by the stabilized construction entrance. An effective stabilized construction entrance should reduce the costs associated with street sweeping.
Traditional Sediment Control Trackout BMPs
Stabilized Construction Entrance, Rock Vehicle Tracking Pad
Aggregate Vehicle Tracking Pads were the first sediment control devices to be used. A Vehicle Tracking Pad (VTC) consists of a geofabric topped with aggregate. Mud and sediment fall from vehicle tires and become trapped in the aggregate. When aggregate is compacted with sediment, it is agitated or redressed with additional rock to maintain effectiveness. While commonly used, this technique requires frequent maintenance and is often inadequate resulting in increased street cleaning costs, and jobsite delays.
Wheel Wash, Wash Rack, Tire Wash Station
To avoid these issues, Vehicle Tracking Pads are typically supplemented with another control measure to ensure that sediment is contained. One example is a wash rack which uses pressurized water to clean tires as they pass through. Although wash racks increase the cost of the system, they are an effective way to reduce sediment pollution. However, wash racks introduce water to the trackout control system which must be contained within the jobsite.
Rumble Plates, Rumble Strips, Rattle Guards
An alternative to wash racks are agitation or vibration-based systems such as steel plates, cattle guards, rumble strips etc. which use vibration to shake off debris from vehicle tires. Similar to a cattle guard, soil is excavated underneath the shaker plates which allows sediment and debris to fall through onto the ground. When sediment fills under the plate, the plate is removed, and the area is excavated again. Some plates are laid on top of the ground and collect sediment between the ridges. The plates are cleaned when sediment builds up between the ridges. Vibration helps to shake sediment from vehicle tires but is typically not enough to completely eliminate trackout. Therefore, these systems typically supplement the aggregate vehicle tracking pads and work together to reduce the sediment that leaves the job site.
Road Paving, Road Pavement
Another solution which is best suited for industrial plants is to implement paving as a way to reduce trackout. Paving offers a permanent solution to trackout by keeping vehicles off of soil completely. In order for this solution to work, the entire path that vehicles take through the plant must be paved to keep sediment from getting lodged in tire treads and tracked off-site. Although effective, vehicles that take variable routes are not able to utilize this BMP, and in addition, long distances may make this solution cost prohibitive.
FODS: The Future Of Construction Entrances
To address the common issues concerning trackout, FODS Reusable Trackout Control Mats were designed to solve trackout needs for any application. Instead of supplementing your existing aggregate vehicle tracking pad, FODS trackout mats can be used as a standalone solution. FODS mats are modular and can be deployed to suit the needs of each project.
The FODS Trackout Control Mats use a unique, patented design which incorporates pyramidal shapes to remove sediment from vehicle tires. These pyramids spread tire tread, or lugs, to allow trapped debris to come loose. This design allows more sediment to be removed from vehicle tires than other trackout products and solutions. Compared to traditional rock entrances, FODS mats have been proven to reduce street sweeping by up to 59% even on muddy construction sites with heavy traffic.
Because FODS are more effective than traditional rock tracking pads, fewer tire rotations are required to remove sediment. The Colorado Department of Transportation has recognized the effectiveness of FODS mats compared to aggregate systems. CDOT specifies a 70 foot rock Vehicle Tracking Pad, or a 35 feet entrance constructed of FODS Pre-Manufactured Construction Entrance Mats as an alternative. This indicates an expected effectiveness of 200% compared to traditional trackout control systems.
Our trackout control mats are a rockless trackout control system which does not degrade over time. The use of FODS trackout mats eliminates the need for aggregate redressing throughout the project. Quick and easy maintenance keeps sediment trackout in control and reduces the risk of project delays.
FODS can be installed in as little as twenty minutes without requiring heavy equipment. Compared to steel plates, FODS are extremely lightweight and can be installed without the need for heavy equipment. In addition, no excavation is required to deploy the FODS Trackout mats.
This modern trackout solution is making an impact on contractors around the world.
Key benefits of FODS construction trackout mats compared to traditional solutions:
- Quick Deployment
- Increased Effectiveness and Compliance
- Reduced Road Cleaning
- Effective in Wet and Dry Conditions
- Can Be Deployed without Excavation
- Easy Maintenance and Significantly Reduced Repairs
- Extreme Durability with Expected Lifespan of 10 Years
- Industry Leading Cost-Per-Job
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Additional Resources
EPA SWPPP Resources & Examples
History Of The Clean Water Act