Development of reservoir capacity loss model using bootstrapping of sediment rating curves

ABSTRACT

Significant developments have been made in understanding the process of reservoir sedimentation. However, predicting reservoir capacity loss (RCL) is still a complex problem. In estimating RCL, a number of challenges are encountered. These are majorly associated with the prediction of sediment load, trap efficiency and deposited-sediment bulk-density. The aim of the present study is to develop an RCL model. RCL experienced by the reservoir, for a longer time period, is estimated using the sediment rating curve (SRC), developed from discharge and sediment concentration, observed over a shorter time frame. The developed model is based on non-parametric bootstrapping of SRC and the inverse relationship of the coefficients of the rating curves. The established RCL loss model is applied to Shetrunji Reservoir, India. The model calibration and validation suggest that its efficiency to predict sediment concentration, sediment load, RCL and gross storage capacity is satisfactory. The present research methodology can be used for any other reservoir to compute RCL. The proposed model is important for field use as dam operators can easily predict the impact of different hydrological events on reservoir capacity and can plan the operation of flushing, sluicing or sediment bypasses.

KEYWORDS:

• Sedimentation
• suspended sediments
• hydrometric observation
• hydrographic survey
• sediment rating curve
• bootstrapping

Acknowledgments

We thank Gregory L. Morris, P.E., Ph.D for the motivation and assistance he provided in taking up this research, and R. N. Sankhua, Ph.D, Chief Engineer (South), NWDA, Ministry of Jal Shakti, Govt. of India for comments on an earlier version of the manuscript, although any errors are our own and should not tarnish the reputations of these esteemed persons. We are grateful to the CWC, India for collecting and archiving the hydrometric dataset. We would like to thank Shetrunji Dam authority for the reservoir water budget and hydrographic survey data. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Disclosure statement

No potential conflict of interest was reported by the authors.