Lake Erie Cliff Erosion Prevention Demonstration Project
Presque Isle Bay,
Erie-Western Pennsylvania Port Authority
Basin Program Funds:
In 1998, a severe landslide occurred on Erie’s west bayfront causing over $60,000 in damage to waterfront structures and public infrastructure. The area has a geological composition found along much of the Great Lakes shoreline. This precarious layering of sandy loams, clay and slate makes for an unstable situation, worsened by rainwater and the removal or destruction of trees along cliff and ravine banks. Slumps such as the 1998 event introduce hundreds of cubic yards of soil into Presque Isle Bay, which takes the ecosystem years to recover. Erie County, Pennsylvania has approximately 60 miles of Lake Erie coastline in addition to a multitude of stream banks of similar composition, all of which share the potential for erosion. While most lake cliffs are subject to damaging wave action, the project area is not. Instead, the cliff’s problems have roots in its geological composition as well as man-made ones.
In terms of human activity, one of the problems along the Great Lakes coasts and within watershed (not unique to Erie) has been the removal of trees and other vegetation in an attempt to improve waterfront views. Often done illegally and with little regard for future consequences, tree removal has been a major problem along Lake Erie cliff banks causing substantial harm. Another problem is amount of impervious surfaces in the city of Erie and Pennsylvania’s Lake Erie Basin. Paved surfaces and the failure of the stormwater sewer system and drinking water delivery system have also contributed to the unstable nature of the cliffs and stream corridors by introducing more water into the soils or at an accelerated rate.
In May 2001, an official from the Department of Environmental Protection’s (DEP’s) Coastal Zone Management Program convened a meeting with the DEP, Port Authority, Erie County Soil Conservation District, and concerned residents and property owners. As a result of the meeting, the Port Authority did a preliminary investigation into the erosion problem with the help of the Erie County Soil Conservation District and an arborist from the Cooperative Extension Office. Following their recommendations, the Port Authority will conduct an investigation into the source of the groundwater.
- The Port Authority will announce the project at its bi-weekly public meetings, and through other outlets such as its private and public partners and the media. The Pennsylvania Lake Erie Watershed Association represents an important forum for the project to be discussed and developed.
- Urban Engineers of Erie conducted a subsoil investigation to determine the source of groundwater south of the project area. The investigation involved working with the local water and sewer authorities and the city of Erie.
- Once the source is determined a design strategy will be completed by Dahlkemper Landscape Architects, which has previously designed a successful Great Lakes Commission-funded project with similar goals.
- To capture the estimated volume of natural occurring groundwater, the Port Authority projects that 400 linear feet of solid drain outlets need to be installed to capture and divert the groundwater.
- An 800 linear foot interceptor drain will be installed beneath the topsoil to carry groundwater to an appropriate location. 800 linear feet of cliff bank will be re-seeded.
- Dahlkemper will lead a series of field workshops to illustrate this technology. The process will be recorded on video and through photographs and slides to present to other interested property owners and public agencies.
Geotechnical specialists at Urban Engineers of Erie, Inc. (the main sub contractor on this project) completed a topographic survey of the study area. A subsurface investigation was performed including test borings, laboratory testing, ground waters level monitoring, and engineering analysis and evaluation. Urban Engineers designed additional vegetation to alleviate slope erosion, explored methods to increase the stability of the bluff slope and developed conceptual stabilization designs, and provided budget cost estimates for the conceptual designs.
A draft report from Urban Engineers to the Port Authority highlighting the existing conditions at the project area, the results of the subsurface investigation, and slope stability analysis was issued in June, 2004. Urban discussed the different strategies to prevent further erosion of the project area, their costs and possible effectiveness. They also met with the Port Authority to discuss how best to prevent erosion on the slope using a combination of vegetation, groundwater diversion, and manmade structures.
Contact: Mr. Tom Maggio, 814-455-7557