Time series modelling for river flow regulation: a study on Engare Narok river, Kenya

Time series analysis of monthly flows as recorded at a river gauging station is performed in order to develop a stochastic model for the generating mechanism. The model is used to generate flow sequences of similar statistical characteristics as the historical series. Annual firm yield-storage relationship is developed from the historical flows. The firm yield- storage curve may be used to select appropriate storages for given demand specifications for simulation studies on the proposed reservoirs. The reliability of the relationship between firm yield and storage is checked using the generated equally likely sequences. Storage-firm yield-probability of failure curves are developed through mass balance computations using the synthetic series. The curves are considered useful decision tools in the choice of an appropriate storage capacity for a desired annual firm yield.