Ensuring Construction and Stormwater Compliance During Wet Weather Events

The potentially strong El Niño and exceptional rain this winter requires project owners pay special attention to Construction General Permit (CGP) and Stormwater Pollution Prevention Plan (SWPPP) regulations to ensure construction site compliance and avoid project delays and violations.

Paul Walsh, a Qualified SWPPP Practitioner (QSP) with Dudek, said “The most effective SWPPP designs utilize robust environmental knowledge to ensure regulatory compliance, while minimizing SWPPP implementation and maintenance costs.”

Best Management Practices

Development of best management practices (BMPs) is a great way to facilitate compliance with regulations, Walsh said. One of the most effective and least expensive BMPs is site management. Effective site management includes:

  • Completing grading work in stages so no more vegetation than is necessary is cleared from the site, which minimizes erosion risk in the case of a rain event; and
  • Building earthen water checks to reduce flow velocity and trap sediment flow, and detention ponds to help minimize erosion and sedimentation.

An up-to-date BMP “wall map” at the construction site is also crucial, and its presence will be verified by a Regional Water Quality Control Board (RWQCB) inspector, should one visit the site. BMPs that are relocatable and reusable can save money by adjusting to the site as it changes, and by having the ability to be used on future projects.

Additional Compliance Considerations

If the National Oceanic and Atmospheric Administration (NOAA) predicts a 50% or greater chance of rain, a QSP must prepare a Rain Event Action Plan in the 48 hours prior to the predicted precipitation event. If a half-inch or more of rain occurs, stormwater sampling must be performed for pH and turbidity using equipment that meets CGP requirements.

Walsh offers the following additional tips for CGP and SWPPP compliance:

  • Train construction staff to identify potential problems and catch issues early before they become significant problems;
  • Avoid track-out from a project site—a red flag to city and RWQCB inspectors—by ensuring mud is removed from all construction vehicles before exiting the project site; and
  • Devise appropriate seed mixes and revegetation methods to obtain the plant cover needed to meet the Notice of Termination requirements.

Exceptional Circumstances

Most projects are subject to these regulations, Walsh said, however the following exceptions exist for sites less than five acres:

  • Sites less than one acre (43,560 square feet (sf)) are automatically exempt from regulations; and
  • Work completed during the drier months on sites that are 1−5 acres (217,800 sf) in size may be eligible for a waiver.

A waiver can be obtained by submitting a Notice of Intent and a Sediment Risk form through the State Water Board’s online Stormwater Multiple Application and Report Tracking System. The submitted information must demonstrate that the project will not pose adverse impacts to water quality, and data must indicate that the rainfall erosivity factor is less than five.

The rainy season need not stop construction activities; however, to minimize avoidable project delays and cost overruns due to erosion damage or violations, focused attention should be paid to compliance with Construction General Permit (CGP) and Stormwater Pollution Prevention Plan (SWPPP) regulations.

Paul Walsh is a Qualified SWPPP Developer (QSD) and Certified Professional in Sediment and Erosion Control (CPESC) with 23 years’ experience. He has extensive experience performing mitigation installation monitoring, construction compliance monitoring, and SWPPP monitoring. For more information, contact him at pwalsh@dudek.com or 760.479.4265.

Pete Trotta is a Qualified SWPPP Practitioner and QSD, and has more than 18 years’ experience specializing in field supervision and coordination of native habitat restoration installation and maintenance projects. For more information, contact him at ptrotta@dudek.com.