CS(AR)-4/2004 : Water balance for Dhasan basin in Madhya Pradesh

Abstract

The estimation of water balance is necessary in the water resources development not only for economic appraisal of the project but also for checking the reliability and general pattern of the availability of water from month to month. As the planning, development and operation of the water resources projects in a river basin is very much dependent upon the availability of water, in required quantities, the water balance study is imperative. Therefore, water balance study in different time periods and its dependability has to be carried to conceive water resources development projects and ascertain its success for long term operation for a particular purpose for which it is meant. The water balance is useful for determining or predicting some of human impacts on the hydrologic cycle. The water deficit and the water surplus in the basin will eventually be evaluated from the water balance study, which is an essential part to be carried out before deciding an irrigation project. The present study involves the evaluation of water balance components for Dhasan basin in Sagar district, Madhya Pradesh. The catchment area under the study is 2049 sq. km. and extends on both sides of Dhasan river. Thornthwaite and Mather method (1957) has been used for computation of various components of water balance like water surplus, water deficit runoff etc. The study reveals that the on normal basis, the basin has a annual water requirement of 1770 mm whereas the rainfall is 1149 mm and actual evapotranspiration is 821 mm. Computations have revealed a water surplus of 327 mm during monsoon months of July, August and September whereas the water deficit during the remaining period is 948 mm. The water deficit actually starts from the month of October, i.e. soon after the withdrawal of the monsoon from the basin and generally increases with onset of the summer season. Since the wheat is the major crop being sown during rabi season in the catchment area, irrigation has to be planned accordingly for the crops. Moreover, since the annual water deficit is much more than annual water surplus, the basin may be considered to be drought prone. This study will be useful to the Water Resources Department, Govt. of Madhya Pradesh to assess the availability of water in the basin and plan the water resources projects accordingly so as to obtain optimum yield from the crops by providing timely irrigation.