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Typically referred to as a “swip,” the Stormwater Pollution Prevention Plan (SWPPP) has a distinguished presence on construction sites. In general, SWPPPs are required for construction projects disturbing at least one acre of land, as mandated by the New York State Department of Environmental Conservation (NYS DEC). However, in some instances, the threshold of disturbance requiring a SWPPP may be more stringent and much less than one acre. Certain local municipalities serve as a Municipal Separate Storm Sewer System agency (MS4), with jurisdiction granted by the NYS DEC. Their primary purpose is to prevent soil erosion, pollutants and sediment transport into water courses, thereby protecting both the environment and the built community from contamination.

The Components of an Effective SWPPP

A comprehensive SWPPP includes detailed strategies addressing water quality, water quantity, and erosion and sediment controls. For example, parking lots and roadways will feature inlet protections to intercept soil sediment and other contaminants before entering the storm system. These preventative measures are crucial for reducing the burden on urban stormwater systems during heavy rainfall. In instances where storm discharge enters a combined sewer or challenge flood ways, it is critical to control release volumes running offsite and avoid overburdening downstream bodies of water or sewage treatment plants. Disturbed construction sites require other temporary protections as well to head off sediment transport and slow down runoff before it circulates into nearby tributaries. Typical erosion control measures consist of silt fencing, silt socks, and check dams, to name a few.

Following significant rainfall events, inspecting the site within 24 – 48 hours is important to ensure that the site remains stable and can continue to provide erosion and sediment controls as required. If any management practices are disrupted or damaged, they will require immediate attention and repair.

Site-Specific Measures

Every SWPPP must be executed as site-specific. Our office regularly conducts site inspections for construction sites. Whether it be development for a new academic building, parking lot, upgrades for a length of underground utility infrastructure, or the installation of a large-scale photovoltaic solar farm, the site disturbance needs to be contained. The regulatory best management practices (BMP) must be implemented. Weekly routine SWPPP inspections insure that both temporary and post-development measures are upheld to the professional design documents. What is important to understand is that even with well-intended temporary erosion and sediment control measures in place, a SWPPP inspector needs to evaluate their performance throughout construction.

SWPPPs should always be considered a “living document” and adjustments may need to be made for underperforming practices as deemed necessary. There are site activities that often change how runoff occurs. Most often we experience construction logistics or sequencing by the developer that can work against the design intent of the SWPPP and thus requires adjustments or additional erosion control measures.

KHH’s Role in SWPPP Compliance

At KHH we take a prudent approach to monitoring SWPPP compliance. Our team conducts weekly site visits—more frequently if needed—checking to ensure that all erosion control measures are in place and functional. During these visits, we document our observations, noting the date, time, and weather conditions, including any precipitation leading up to our visit. This information is essential for transparency and made available to the DEC or MS4, who may conduct their own “parallel” inspections.

Our trained and certified staff go on-site to assess conditions, check the upkeep of exposed soil areas, and monitor the performance of temporary and permanent practices. As a professional consulting firm that also prepares the SWPPP designs and documents for various site projects, we witness firsthand the dynamics of hydrology on a construction site through our engagement with SWPPP inspections. If non-compliance issues arise, we are able to recommend corrective actions to ensure adherence to regulatory standards and avoid negative site impacts.

The Importance of SWPPPs

For the natural and built environments, a well-implemented SWPPP serves as a safeguard against adverse environmental impacts from construction activities. It’s vital for preventing soil loss or displacement that could alter critical habitats or contaminate water sources. It wasn’t very long ago when loosely regulated development of our built environment greatly impacted our natural resources and accelerated the polluting of our waterways. Efforts to reverse this trend were implemented and expanded about 25 years ago by the Environmental Protection Agency (EPA) and state governments around the country. Known as “Phase II” of the Clean Water Act, states like New York were tasked with addressing stormwater runoff on previously unregulated construction activity on sites smaller than 5 acres and small MS4 operators. Site construction, especially large-scale site clearing, needed to be addressed and better enforced. Tighter disturbance tolerances were imposed to stem the environmental destruction caused by out-of-control site disturbances. The current SWPPP requirements and practices being performed are showing positive results in stemming the speed of destruction to our environment.

SWPPP Completion

Ultimately, a successful SWPPP ensures that a construction site is managed effectively by reducing environmental impact throughout the project’s development. SWPPP permitting remains in effect until all disturbed site areas are stabilized (paved and/or fully established with vegetative cover). A SWPPP is considered complete only once a final report is submitted in the form of a Notice of Termination Act (NOT) by the SWPPP Inspector to the authority having jurisdiction, whether that be the designated MS4 or the state DEC.

Conclusion

To maintain compliance and efficacy, it is imperative to develop a SWPPP tailored to your site’s specific conditions, keep it updated, and implement it thoroughly. KHH has the experience and trained professional staff to appropriately design sites for stormwater management and also provide inspections of BMPs during construction to uphold regulatory demands and assure a sustainable environment.