PennFuture releases model law to protect streams from stormwater runoff

Environmental group PennFuture released a model ordinance on November 26 that provides a template for Pennsylvania municipalities to establish green stream buffers. The document aims to address the growing impact of stormwater runoff caused by large-scale warehouse construction and the expansion of hyperscale data centers across the state.

Brigitte Meyer, a staff attorney at PennFuture, explained that these large projects often cover hundreds of acres with paved surfaces. These impervious areas generate thousands of gallons of stormwater that flow into local waterways. Meyer stated that the group created the ordinance to provide a universal solution rather than reacting to each new development individually.

The proposed ordinance focuses on riparian buffers, which are zones on either side of waterways planted with native vegetation. These areas serve multiple functions, including flood mitigation, sediment removal from runoff, and habitat creation for wildlife. Meyer noted that the buffers also provide corridors for animals to move between larger natural areas, supporting population diversity.

The model is designed for any Pennsylvania town to adopt with local modifications. It includes provisions for buffers along wetland borders. Meyer acknowledged that while some municipalities are already familiar with the concept, others may not be. The group aimed to create a working document that local officials can adapt to their specific community needs.

Murrysville officials have already implemented riparian buffers in locations such as Murrysville Community Park. Emily Mallisee, the community development director, described a project along Farm Road that served a dual purpose. The area was developed for recreational use while also protecting the headwaters of Steele’s Run, a high-quality stream.

Mallisee noted that while planting buffers is not inexpensive, the long-term maintenance costs are low. Meyer added that once established, the vegetation filters sediment without requiring ongoing financial support. This efficiency is particularly valuable for communities participating in the state’s Municipal Separate Storm Sewer System program.

MS4 communities receive annual targets from the state Department of Environmental Protection regarding sediment prevention. These targets often act as unfunded mandates. Mallisee said that riparian buffers help Murrysville meet these goals while protecting local streams. The town also experiences frequent flooding during heavy rain, and buffers contribute to risk mitigation.

Raegan McKelvey, program coordinator for the Jacobs Creek Watershed Association, emphasized the low maintenance requirements of these buffers. He pointed out that allowing wildflowers to grow near stream banks creates a natural filter and reduces the need for mowing. This approach contrasts with the practice of cutting grass right up to the water’s edge.

Riparian buffers control flooding by creating a rough surface that slows water flow and increases contact with absorbent ground. Plant root structures also help water seep into the soil. Mallisee said Murrysville typically looks for areas with 30 to 50 feet of buffer on either side of stream banks. PennFuture suggests larger buffers of 100 to 150 feet, with some cases requiring up to 300 feet.

In Oakmont, an older buffer along Plum Creek in Dark Hollow Woods requires repair due to stormwater erosion and invasive species. Phyllis Anderson, assistant borough manager, said the work is part of the borough’s master plan for the park. This plan is integrated into the town’s comprehensive strategy for long-term sustainability.

Meyer said the model ordinance addresses gaps in state law, which only mandates buffers in specific circumstances. The group acknowledged that buffers affect the developable area of a property. The ordinance scales buffer sizes based on the overall size of the development to balance these interests. The full text is available at PennFuture.org.