5 Construction General Permit (CGP) SWPPP Solutions
| Karen Hamel |

Five Construction General Permit (CGP) SWPPP Solutions

Five Construction General Permit (CGP) SWPPP Solutions

Technologies and Best Management Practices (BMPs) continually emerge and improve. This constant state of progress is a great thing when it comes to improving the quality of our nation’s waters. It’s also one of the reasons why the Clean Water Act (CWA) tasks the federal Environmental Protection Agency (EPA) with reviewing and renewing the National Pollutant Discharge Elimination System (NPDES) Construction General Permit (CGP) every five years.

Between permit cycles, EPA collects comments and proposals from various stakeholders, identifies changes and modifications to state permits, and reviews information from other sources when considering which permit clarifications and additions to propose and adopt for the next five-year cycle. In 2022, nine additions and 21 clarifications were made to the existing 2017 Construction General Permit (CGP).

The federal EPA issues NPDES permits in Massachusetts, New Hampshire, and New Mexico as well as US territories (except the Virgin Islands,) Puerto Rico, the District of Columbia, Tribal Lands, and for federal projects in certain states. In the other 47 states, permitting occurs at the state level.

Whether you’re getting ready to submit your next Notice of Intent (NOI) or looking for some new BMPs to strengthen your Stormwater Pollution Prevention Plan (SWPPP), focusing on these five areas can help you improve your operations and prevent pollutants from leaving your construction area.

1. Perimeter Controls

Perimeter controls provide the last line of defense against pollutants leaving a construction site. Most are engineered to capture dirt and silt. Some also capture trace oils and other contaminants. The most common types are silt fences, compost filter socks, gravel barriers, and temporary diversion dikes.

The 2022 Construction General Permit (CGP) clarified that sediment controls need to be installed upgradient of natural buffers, and along the perimeter of sites that are downslope from exposed soil or disturbed areas. (2022 CGP, Part 2.2.3)

Perimeter controls must also be effective. For example, stormwater cannot circumvent the edges of a control. Sediment must be removed before it accumulates to ½ of the height of the control device to prevent failure. Perimeter controls need to be inspected after storm events and repaired or replaced (if necessary) to prevent pollutants from being discharged. (2022 CGP, Part 2.2.3)

2. Drain Inlets

Storm drain inlets can be a great asset to keep rainwater and snowmelt from flooding your construction site after a storm. But unless the stormwater is directed to a sediment basin, sediment trap, or other control, the inlet must be protected. (Part 2.2.10, Part 7.2.4.g, Part 7.2.6.b.iv)

Without a sediment basin or similar control device, storm drain inlets are a direct path to receiving waters. Protecting inlets with devices that capture sediment and other pollutants helps to prevent plumes and sedimentation at outflows.

To remain effective, inlet protection controls need to be cleaned or removed and replaced when they become clogged or when sediment accumulates at the device’s inlet. Therefore, all inlet protection devices should be included in routine inspections as well as inspections after storm events, with sediment deposits being removed by the end of the business day that they are discovered. (Part 2.2.10)

3. Liquid Construction Product Wastes, Wash Water and Cleanout Waste

Concrete, paint, stucco, curing compounds, and form release oils are common construction wastes. When containers that previously held these compounds, or applicators that were used to apply these compounds are rinsed or washed, the wash water needs to be properly managed. (Part 2.3.4)

Properly managing wash water from cleaning applicators and containers includes:

  • Locating washout and cleanout in designated areas that are as far as possible from storm drain inlets or receiving waters
  • Directing wash water to an adequately-sized, leak-proof container or pit that prevents overflows and allows the water to be collected
  • Preventing water from being dumped into storm inlets or receiving waters; or allowing it to infiltrate into soil
  • Treating or disposing of the wash water in accordance with all applicable regulations

Hardened concrete waste should be collected and managed with other solid construction wastes.

4. Container Management

Properly managing containers not only prevents hazardous materials from entering the environment; but also ensures that each product will be available and ready for use when it is needed for the project. All containers that hold hazardous materials need to be kept closed when they are not in use to help prevent spills and hazardous air emissions. (Part 2.3.3, Part 7.2.6)

ProductStorage and Handling Requirements
Building materials and products
  • Cover materials to minimize the exposure to precipitation and prevent discharges
Pesticides, herbicides, insecticides, fertilizers, and landscape materials
  • Cover containers to minimize the exposure to precipitation and discharge of pollutants
  • Comply with all application and disposal requirements included on the label
Diesel fuel, oil, hydraulic fluids, other petroleum products, and other chemicals
  • If managing in accordance with an SPCC plan, container management is considered to be in compliance
  • Containers with capacity less than 55 gallons
    • Must be water-tight, closed and sealed when not in use
    • Stored on a containment pallet or similar device to capture leaks and spills (if stored outdoors)
  • Containers with 55 gallon or greater capacity
    • Must be water-tight, closed and sealed when not in use
    • Must be stored at least 50 feet from receiving waters and drain inlets
    • Must be covered, or secondary containment must be provided
  • Have a spill kit in good working condition and personnel who are trained to clean up spills
  • Dry cleanup methods must be used for spills. (No hosing down the area)
  • Eliminate the source of a spill to prevent further discharges
Hazardous or toxic wastes (paints, caulks, sealants, fluorescent light ballasts, solvents, wood preservatives, curing compounds, acids, etc.)
  • Segregate from construction and domestic wastes
  • Store in sealed containers and label in accordance with RCRA requirements
  • Provide secondary containment if containers are stored outdoors, or provide an effective method of preventing discharges (such as spill kits)
  • Clean up spills immediately, using dry cleanup methods (Do not hose down the area)
  • Eliminate the source of spills to prevent further discharge
  • Follow all other applicable regulations for storage, handling, and disposal of hazardous wastes
Construction and domestic wastes (packaging materials, scrap, masonry products, timber, pipe and electrical cuttings, plastics, styrofoam, concrete, demolition debris; and other trash or discarded materials)
  • Provide sufficient waste containers
  • Containers with lids must be kept closed at the end of the day and during storm events
  • Containers without lids must be covered or provided with secondary containment
  • Wastes must be cleaned up and placed in waste containers each business day
  • Container overflows and litter must be cleaned up immediately
Sanitary wastes
  • Secure portable toilets so that they cannot be tipped or knocked over
  • Locate portable toilets away from receiving waters, drain inlets, or other natural site drainage features

5. Dewatering Operations

Dewatering includes draining accumulated stormwater and/or groundwater from foundations, vaults, trenches, or any other areas where it has accumulated. When these areas are drained, water pollutants – such as sediment and oil sheens – need to be contained onsite to prevent pollution.

The 2022 Construction General Permit (CGP) clarified and updated the requirements for dewatering operations. Inspections must take place each day there are dewatering activities. Operators must:

  • Specify on the NOI that dewatering operations will be conducted
  • Route water through a sediment control device
  • Replace and clean filtering media on dewatering devices according to the manufacturer’s specifications
  • Look for signs of visual turbidity such as cloudiness, opaqueness, or water that has a visible contrast to receiving waters during inspections
  • Prohibit discharges containing visible floating solids, foam, or oil sheens
  • Allow dewatering water to infiltrate in well-vegetated, erosion-resistant, upland areas whenever possible
  • Prohibit the use of receiving waters as part of the treatment area
  • Haul away backwash water or return it to the beginning of the treatment process
  • Keep records of inspections, including photographs

Preparing for Construction General Permit Updates

Regularly reviewing the BMPs listed in SWPPPs, and upgrading them to reflect newer, more effective technologies can help operators prepare for new requirements in each EPA permit cycle and assure that they’re doing their part to prevent pollution.

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If you have a question about the 2022 Construction General Permit (CGP), we’re here to help. Our team can address your questions and assist in implementing changes to your SWPPP. Call 814-822-2004 or email sales@halenhardy.com.

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