Estimates of sediment trapping rates for two reservoirs in the Lake Erie watershed: Past and present scenarios

Abstract

Sediment accumulation can significantly impact the useful life of dams and the multiple functions served by those dams such as flood attenuation, hydropower, and water supply. However, there is only limited information, and even fewer physical measurements, assessing the rate of sediment accumulation in reservoirs behind dams. Many of the dams within the Great Lakes Watershed were constructed between 100 and 120years ago, and there is reasonable concern that these dams and their associated reservoirs may be reaching capacity with respect to sediment storage. As a reservoir reaches its sediment storage capacity, there are numerous risks. Excess sediment can compromise the water intake for supply systems. Dam failure or removal can potentially allow large quantities of impounded sediment to migrate downstream, negatively impacting fish habitat and water quality. This research investigates the historical function of dams as sediment storage points. Also, this research assesses the effect of anthropogenic influences including land use change and dam construction on sediment yield and accumulation within the Lake Rockwell and Ballville Dam watershed. To better understand the historical and current sediment yield within the Lake Erie watershed, Soil and Water Assessment Tool (SWAT) models of the Lake Rockwell and Ballville Dam watersheds were developed. The resulting model suggests that the average of sediment accumulation rate within Lake Rockwell Dam reservoir varies between the minimum of 1.6 and the maximum of 4.6g/cm2/yr from 1988 to 2007. Within the Ballville Dam reservoir, the rate varies between the minimum of 2.6 and the maximum of 23.2g/cm2/yr from 1980 to 1999.