Dams are constructed for hydropower, flood control, and to provide water for irrigation. The life span of dams world-wide is often controlled by the rate of sedimentation in the reservoirs resulting in the loss of storage (White, et al, 1999). If a dam is constructed to permit flushing of sediment from the reservoir, and the correct hydraulic conditions can be met, fine sediments can be transported downstream. Dams are decommissioned because they become structurally unsound, their storage capacity is reduced by sedimentation, or they block the passage of migrating fish.

When fine sediments from dam decommissioning or sediment flushing are transported downstream they pose risks to water quality by increasing turbidity and the possible release of contaminates form the stored sediments. Increased turbidity can limit the availability of food for fish by reducing the predator-prey reactive distance, and increases in suspended sediment concentrations can impact macroinvertebrate habitat.

Understanding the impacts of sediment transport from reservoir sediment removal and its effect on the environment is complex. Both theoretical approaches and monitoring are required to understand and mitigate the process. RiverMetrics™ can provide monitoring solutions for measuring turbidity and estimating suspended sediment and contaminate loads.