The Influence of Conceptual Flow Simulation Model Parameters on Model Solution

This article investigates the influence of conceptual flow simulation model parameters (i.e coefficients and constants that need to be estimated in calibration) on model solution (surface runoff) to understand the characteristics of the model. A new conceptual watershed yield model (WYM) was employed. There are four physical parameters, two fitting coefficients and two initial estimates of the surface water and groundwater storagesthat control the functioning of the model. The conceptual model was applied on Ling River near Kahuta and detailed sensitivity analysis was performed to explore the most sensitive model parameters. The most sensitive model parameters worked out were C <Subscript>g</Subscript> (a fitting coefficient, which reflects the rate at whichgroundwater runoff occurs), w <Subscript>r</Subscript> (watershed retention is the initial rainfall losses before runoff begins), p <Subscript>gr</Subscript> (inputparameter that reflects the discharge capacity of the groundwateraquifer). The model parameters like i <Subscript>c</Subscript> (infiltration coefficient), g <Subscript>wsm</Subscript> (input parameter that depends on the subsurface storage available in the watershed) and e <Subscript>p</Subscript> (input parameter) have negligible effect on model solution. It was observed that w <Subscript>r</Subscript> (watershed retention) is the only surface runoff controlling parameter and p <Subscript>gr</Subscript> and C <Subscript>g</Subscript> are the groundwater runoff controlling parameters. Copyright Kluwer Academic Publishers 2002