UNDERSTANDING THE GOOD FORTUNE OF STREAM RESTORATION AT SLIPPERY ROCK UNIVERSITY

Slippery Rock University contracted a stream restoration project in recent years. We are examining these events to better understand the process and provide a third-party analysis of its efficacy. The first task was to remove 6 low head dams on an unnamed tributary to Slippery Rock Creek. Like hundreds of low head dams in western Pennsylvania, these dams were largely decrepit. They were built pre-1970, repaired in 2002, and neglected since. Their upstream pools were overloaded with sediment and their faces were disintegrating. In high flow events, the pools would overflow. They were a public safety hazard. The decision was made to remove them in summer ’23. Once schematic plans were made, permits obtained, and bids reviewed, work began in May. The crew began upstream. First, aquatic wildlife was relocated. Next, the dam pools were dewatered. Clear, unperturbed water at the surface was pumped downstream. More care was taken with the sediment-laden water and mud. The mixture was pumped through filter bags and rock filters to reduce turbidity. Cofferdams were built to keep the work area dry. Once the dam and its footer were removed, the crew excavated the accumulated sediment to a rough grade. Work was strategically scheduled during fair weather to reduce erosion of the exposed fine-grained alluvium. Thorough stormwater management and erosion prevention plans were enacted in accordance with NPDES permits. Next, the intricate work of stream restoration began. GPS was used to place root wads, large woody debris, and rock riffles to mirror the engineering plans. These structures mimicked a meandering stream and created niche habitats for aquatic wildlife. By law, 0.49 acres of wetland were added to offset the 0.201 acres of wetland permanently impacted by the construction. The project was completed by planting the wetland, stream bank, and riparian buffer zones with the appropriate species to promote streambank integrity, create natural habitats for native species, and minimize erosion. The project succeeded in returning this unnamed tributary back to some semblance of its natural state. Robert Frost, in his poem A Brook In The City, tells the all-too-common modern story of streams to never again see the light of day. The reach of stream rebuilt is the lucky one. Miles of other streams in the vicinity will remain entombed in sewers forever.