ABSTRACT
Sustainable reservoir management alternatives (e.g. flushing and routing) are often limited by downstream concentration constraints. Designing reservoir operations to pass sediment and maintain downstream concentration constraints can be difficult. A 1D sediment transport model (HEC-RAS) was developed for Spencer Dam and compared to measured results from a four week reservoir flush and the subsequent five months of reservoir deposition after the flush. Then the calibrated model was used to design two reservoir sediment reoperation alternatives to mitigate downstream effects. Sediment commands in the HEC-RAS Operational Rules feature automated gate operations for 1) concentration controlled flushing operations that limited downstream sediment releases to a defined limit and 2) sediment routing operations that limit downstream concentrations to the natural upstream concentrations flowing into the reservoir.
