The study develops a regional conceptual catchment water balance model for five catchments in the Western Ghat region of Karnataka. The model can be used to estimate the water yield from ungauged catchments located in the region.
The water yield is an integration of discharge as a function of time for a specified duration and reflects the volumetric relationship between rainfall and runoff. The estimation of water yield is required for solution of water resources problems normally encountered in design of storage facilities. It is of use in understanding the water availability for agriculture, industrial and drinking purpose as also for estimating the dependable water supply for power generation and irrigation projects.
The regionalized parameters of the catchment water balance model have been obtained by developing a relationship between model parameters such as wetting potential, vaporization potential, initial abstraction, coefficient of baseflow, surface flow, mean annual rainfall and vegetation cover of the basin. The coefficient of determination between vegetation cover and the model parameters were found to be very high, whereas the relationship between mean annual rainfall and model parameters is very low.
The regional parameters obtained are compared with calibrated parameters and found to be within the tolerable limits. Water balance components are simulated using both regionalized and calibrated parameters of the model. The variation between the simulated values is within ten percent. Hence, it is suggested that the model parameters can be obtained from the established relationship between them and the vegetative cover of the basin.
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