What’s the plan?
PWSA is evaluating the conditions of Phipps Run and Panther Hollow Run in Schenley Park and is developing a restoration strategy to resolve the erosion and sedimentation problems in these streams. Resolving these problems will allow additional water to be conveyed from the neighborhoods. Stabilizing the stream banks would prevent further erosion of sediment entering the sewers and exacerbating flooding.
How is this being designed?
Modern development patterns change the way rainwater flows across the landscape. Mown lawns such as the golf course, roadways, and buildings do not slow and absorb rainwater as well as a stable forest ecology can. Thus the rainwater moves quickly across the landscape and accumulates in much greater volumes. This leads to “flash” flooding events which are high in volume and velocity, leading to dramatic erosion. PWSA’s team is looking at strategies to slow the velocity of rainwater from contributing areas and to stabilize trails and stream banks within Schenley Park.
Issues PWSA is exploring include:
- Some existing culverts are broken, clogged, or undersized. This can divert rainwater onto gravel trails where it causes erosion and carries gravel into the streams.
- “Flashy” streams are more likely to flood, causing damage to park trails and amenities.
- Excessive erosion can destabilize stream-banks and hillsides, leading to small and large landslides within the park.
- Restoring the stream so it is slightly wider and not as deep would slow down the stream flow. Reducing runoff and erosion can reduce the amount of sediment carried in the water, preventing sediment deposition that narrows the stream width.
- Redesigning existing drainage of park roads and trails with green infrastructure can reduce runoff and decrease erosion and sediment delivered to the stream.