Application of Vogel and Stedinger (V-S) empirical procedure to develop storage reliability yield relationships for Kainji reservoir System.

Abstract

Storage reservoirs tend to be large and complex systems requiring equally complex mathematical models to simulate their behaviour. What are lacking are simple, reasonably accurate methods which give insight into a wide range of reservoir storage system characteristics and reliability indices. Such methods would be useful for the education of water supply analysts. This study tends to apply the Vogel Stedinger (V-S) procedure to simulate and develop a mathematical model to predict reservoir storages of a within year system. Inflows, out flows and reservoir levels of Kainji reservoir were obtained between 1991 and 2014. Reservoir storages were determined and Vogel Stedinger parameter variables (Sp is the pth quartile of the distribution of required reservoir capacity for 100% failure-free operation over a specified planning period N, Zp is the standardised Normal variate at p%, σ is the standard deviation of annual stream flows, 1 µ and 1 σ are mean and standard deviation of the logarithms of the storages and 1 ϑ is the lower bound of the torage) determined and were used to develop an empirical model for predicting storages and other V-S parameters. The R2 Value (0.72) of the model indicates the strength and reliability of the model. The model could be useful to reservoir managers in overcoming extreme events of flood and drought.