Bluff retreat, sediment budgets, and erosion mitigation on the NW Pennsylvania coast of Lake Erie

This field guide reviews bluff retreat processes and rates; hazards; mitigation efforts; and stakeholder challenges along the erosional NW Pennsylvania bluff coast of Lake Erie, the shallowest and southernmost of the North American Great Lakes. Seven stops progress downdrift to the northeast along a large coastal littoral cell, the western Erie County littoral cell (WECLC), beginning at the Pennsylvania-Ohio state line and finishing where the WECLC transitions to the Presque Isle littoral cell near downtown Erie. In this sediment-starved cell, spatially variable bluff-crest retreat rates over the past half-century average ~0.25 m/yr along the updrift sector of the WECLC and ~0.1 m/yr along the downdrift sector. Much of the retreat is the result of small- and moderate-sized rotational slumps and less frequent but larger translational slides. Key attributes driving bluff retreat include bedrock elevation, beach volume, wave impact hours at the bluff toe, and groundwater flux through the bluff face.