Economic Reservoir Design and Storage Conservation by Reduced Sedimentation

Abstract

A mathematical model has been developed for estimating the design storage capacity of a reservoir by using the expected water demand, storage loss due to sedimentation, and physical and hydrological characteristics of the watershed. Suitable mitigative measures can be incorporated in dam design and reservoir operation to substantially reduce sediment entrapment in the reservoir, and to improve dissolved oxygen levels by releasing hypolimnetic waters from the reservoir. These measures may also greatly reduce streambed degradation downstream of the dam and consequent initiation of a new erosion cycle in the tributaries. Reservoir design based on storage conservation is of prime importance considering the dearth of new feasible sites for reservoirs. Economic analyses for different storage‐maintenance measures (such as undersluices and flushing pipes) have been investigated in terms of reduction in initial reservoir design storage, cost of installing measures, and cost of any dredging operations. These analyses are performed for a site in Illinois for several water‐demand levels and useful lives of the reservoir.