Linear Reservoirs in Series Model for Unit Hydrograph of Finite Duration


Abstract: The unit hydrograph of a river basin can be estimated from the records of rainfall and streamflow by various methods. In this paper, a linear reservoirs in series model is used to derive the unit hydrograph of a certain duration. This approach is similar to that proposed by Nash for the instantaneous unit hydrograph. Expressions are obtained for the unit hydrograph ordinates of the model as function of model parameters, number of reservoirs and storage coefficient. A computer program is developed to simulate the conversion of the rainfall excess to the direct runoff by the model and to optimize the model parameters according to a selected criterion. Application of the method is illustrated in an example.

Keywords: Unit hydrograph, Linear reservoirs, Reservoirs in series

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