Keeping Scott Run in Daylight
Pennsylvania Department of Conservation and Natural Resources, Presque Isle State Park
Basin Program Funds:
The erosive water flows of Scott Run are causing stream bank instability and ravine wall collapse in a small watershed of the southern coastal plain of Lake Erie. This erosion problem is causing sediment pollution, is undermining the structural stability of a high-density residential unit located near the ravine crest, and is adjacent to the location of a new environmental education center currently under construction (the Tom Ridge Center at Presque Isle).
Scott Run is a small Lake Erie tributary that is one of only three streams flowing into Presque Isle Bay. This stream has special significance because Presque Isle Bay has been re-listed by the International Joint Commission (IJC) and the Environmental Protection Agency (EPA) as an Area of Concern in Recovery State, the first so designated. Scott Run is adding significant sediment deposition to the southwestern corner (head) of the bay and is promoting accelerated eutrophication in this embayment of Lake Erie waters. The head of Presque Isle Bay provides significant fisheries habitat, including sites for rare and endangered species, and provides recreational opportunities for fishing and boating; it is also used by scholastic and university sculling crews who are periodically stymied by low lake levels and sediment accumulation.
The primary source of sediment in this stream is from stream bank soils and ravine wall soils. This semi-urban stream is experiencing higher stream flow volumes and velocities resulting from an increase in stormwater runoff in its small urban watershed. Factors contributing to these flows include an increase in impervious surfaces, headwater wetland disturbances, and channelization and enclosure of upstream flows. Rapid and severe erosion along the banks of Scott Run in this area is causing the streamís banks to recede and the ravine walls to collapse.
In August 2001, the Commonwealth acquired the 12-acre property consisting of the stream and the western ravine wall and the western tableland for the purpose of building a regional learning, research and visitor-information facility for the DCNR and Presque Isle State Park. The Tom Ridge Center at Presque Isle is located outside the entrance to Presque Isle State Park and the Department of Conservation and Natural Resources (DCNR) is in the process of acquiring additional greenway to connect the Center and the Park.
The goal of the DCNR solution is to restore the natural flows and features of the land prior to development. The overall long-range purpose is to create a natural stream erosion control system and a mid-bank groundwater erosion control and soil retention system. This system would restore the natural stream and forest regime and would improve groundwater infiltration and recharge in the Scott Run watershed. In the most critical portions of this streamís ravine, the project will recommend and construct various stream bank stabilization and steep ravine wall bioengineered slope stabilization projects using Best Management Practices (BMPs). Following is a list of goals for the project:
- PA Department of Conservation and Natural Resources staff will meet with manufacturers of Best Management Practice (BMP) products to determine which techniques are best suited for the project.
- One or a combination of several BMPs will be incorporated to reduce erosion.
- One public coalition-building meeting will be held involving the Park, the Condominium Association, and other interested parties to explain the principals of BMPs. Sedimentation into Presque Isle Bay will be reduced by approximately ten tons.
- Educational "tours" of the BMP project area will be provided to any interested visitor to the Tom Ridge Center at Presque Isle.
A geomorphic assessment of Scott Run has been performed characterizing the stream in the area between West 6th Street and the confluence with Presque Isle Bay. The geomorphic assessment study includes analyses of the physical, geological, hydrological, biological, and evolutionary history of the stream.
A walk through of Scott Run and its surrounding area within the project limits was performed for this study. Detailed stream inspection notes with photographs were taken at 50 foot intervals along Scott Run. Included in the inspection was the width of flow of Scott Run at the time of study, the condition of the stream along each 50 foot segment, and the condition of the bed, bank and slope on each side of the stream. A historical review of topographical maps and aerial photos indicated that the stream changes that have occurred have evolved over the course of many years. The hydrologic analysis of Scott Run reveals that the base flow in Scott Run is not a significant contributor to erosion of the stream channel. The nature of the watershed in its present condition of development causes large changes in flow in a relatively short period of time.
This study developed 4 viable alternatives for stabilization of Scott Run, three (3) of which include soft engineering technology to keep Scott Run "open". Included in each alternative is a description of each process and a cost estimate for the method.
It is recommended that DCNR evaluate the anticipated land use for the area of Scott Run in the vicinity of the study. Once a determination is made as to the proposed use of the land, this report may be used as guidance documentation for selecting an alternative that best meets the needs of the proposed land use.
Contact: Mr. Harry Z. Leslie, 814-833-7424