Assessing potential removal of low-head dams in urban settings: an example from the Ottawa River, NW Ohio.
This is a study of the scientific component of an effort to restore an urban river by removing a low-head dam. The Secor Dam is owned by a local government entity near Toledo, Ohio. The proposed removal of the last structure impeding flow on the Ottawa River has broad appeal, but the owner is concerned about liability issues, particularly potential changes to the flood regime, the presence of contaminated sediments behind the dam, and possible downstream transport of reservoir sediments. Assessing sediment contamination involved sediment sampling and analysis of trace metals and organic contaminants. Forecasting sediment transport involved field methods to determine the volume and textural properties of reservoir and upstream sediment and calculations to determine the fate of reservoir sediments. Forecasting changes in the flood regime involved HEC-RAS hydrological models to determine before and after dam removal flood scenarios using LiDAR data imported into an ArcGIS database. The resulting assessment found potential sediment contamination to be minor, and modeling showed that the removal of the dam would have minimal impacts on sediment transport and flood hazards. Based on the assessment, the removal of the dam has been approved by its owners.
Roberts
Sheila J
SJ
Department of Geology, Bowling Green State University, Bowling Green, OH, 43403, USA. sjroberts@bgnet.bgsu.edu
Gottgens
Johan F
JF
Spongberg
Alison L
AL
Evans
James E
JE
Levine
Norman S
NS
D004190:Disasters; D019015:Geologic Sediments / Q000737:chemistry*; D009820:Ohio; D045483:Rivers / Q000737:chemistry; D014131:Trace Elements / Q000032:analysis; D014506:Urban Renewal; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply
D014131:Trace Elements; D014874:Water Pollutants, Chemical