Status: this discussion paper is a preprint. It has been under review for the journal Hydrology and Earth System Sciences (HESS). The manuscript was not accepted for further review after discussion.
Assessment of optimal empty flushing strategies in a multi-reservoir system
Frederick N.-F. Chouand Chia-Wen Wu
Abstract. Empty flushing is the most effective approach to evacuate the deposited sediments in the reservoir. However, emptying reservoir essentially conflicts with its water supply operation, thus a feasible strategy of empty flushing should prevent significant increase of water shortage risks. This paper presents a framework of performing empty flushing in a multi-reservoir system, where flushing is carried out in a primary reservoir and the other reservoirs provide backup storage for stable water supply during flushing. A network flow programming-based model is employed to simulate daily joint operation of reservoirs. During the simulation, if the storage of each reservoir achieves the predefined conditions, drawdown and empty flushing of the primary reservoir is activated. During the flushing, if the storage of any reservoir reaches the pre-defined thresholds, then the flushing operation is halted and the simulation switches back to the regular joint operation mode. This simulation model is linked with a nonlinear optimization algorithm to calibrate the optimal parameters. The optimized strategy yields a maximum amount of flushed sediments, while the incremental water shortage is controlled within the acceptable threshold.
Received: 08 Feb 2016 – Discussion started: 07 Mar 2016
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Empty flushing is effective for removing deposited sediments from reservoirs, but draining the storage counteracts the water supply function. In a multi-reservoir system, this limitation can be alleviated through proper joint operation to create favorable conditions to implement empty flushing in one pf the reservoirs. The strategy is optimized to maximize the desilting volume without inducing intolerable water shortage, thus allowing the system to advance toward the goal of sustainability.
Empty flushing is effective for removing deposited sediments from reservoirs, but draining the...
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