ESTIMATION OF MONTHLY RUNOFF FROM SMALL CATCHMENTS

Abstract

The monthly runoff from catchments is one of the important informations needed for the planning of the water resources projects. In many cases, long term data of monthly runoff are not available at the site of interest. However, the meteorological and topographical data such as the monthly areal rainfall, catchment area, land slope, percentage forest cover and mean monthly temperature are usually available. Various types of empirical equations and models have been proposed for monthly runoff estimation, but these have not been tested with adequate data. Many of these methods are quite sophisticated and need elaborate long term data and computer facilities for modelling. Keeping this difficulty in view in the present investigation, the available data from 31-small catchments related to 6 large river basins in India i.e. Barakar, chambal, Damodar, Mayurakshi, Lower Bhavani and Ramganga, have been used to develop a simple deterministic scheme for the realistic estimation of monthly runoff from small catchments. Attempt is made to correlate one of the parameters of runoff equation to meteorological and' topographical factors such as catchment area, percentage forest cover and mean monthly temperature.