INFLUENCES OF HARD STRUCTURES AND CLIMATE ON HISTORIC SHORELINE POSITIONS AND NEARSHORE-SEDIMENT BUDGETS OF FAIRPORT HARBOR, LAKE ERIE, OH

Fairport Harbor is situated near the middle of the southern shore of Lake Erie, where the dominant long-shore transport direction is eastward. The installation of hard structures has resulted in extensive beach progradation to the west and complex nearshore and beach changes to the east of the shipping channel. A 100-year record of shoreline changes and nearshore bathymetry obtained from nautical charts and aerial photographs, integrated with information on climate and the timing of hard structure installation, provide detailed insight into causes for observed spatio-temporal variations in erosion and deposition across the area.

Shoreline and hard structure positions were spatially referenced from a total of 20 maps and aerial images of the study area, covering the timespan between 1901 and 2002. Bathymetry measurements for the years 1901, 1946, and 1983 were digitized and gridded to produce nearshore-surface models to be used in net-change calculations.

Shoreline advance west of the shipping channel measures 500 meters in 100 years. As surface models show retention in prograding nearshore geometries through time, beach area gained is used as a metric for change rather than sediment volume. A constant rate of beach gain of around 6000 m²/yr is punctuated by a decrease to around 2000 m²/yr during the 1940s, possibly attributable to existing drought conditions and reduced wave and current action. Extensive and repeated human-induced shoreline modifications to the east of the channel and a spatially complex record of erosion and deposition there require additional study for reconciliation.