Application of a Distributed Hydrological Model for River Basin Planning and Management

Abstract

Any plan related to inter-basin transfer of water from a water-surplus basin to a water-deficit basin has to take into account the water availability and demands under the present and future scenarios of water use. Any waterrelated activity that takes place in one part of a river basin may have consequences in the other part. Therefore, effective management of water and related environment in a river basin requires an integrated and co-ordinated planning within the basin. A conceptual spatially distributed water balance model, earlier developed at NIH, has been applied to the Upper Bhima basin up to Ujjani dam. Various types of spatial, attribute, and dynamic data are integrated by the model to perform the water balance analysis to simulate various components of the hydrologic cycle at the scale of a river basin. Model computes various components of hydrologic cycle such as rainfall, actual evapo-transpiration, runoff, groundwater recharge, soil moisture change etc. for various land uses in different sub-basins of a river basin. The model brings out total water availability in the basin; water consumed by different uses; and water storage in different hydraulic structures, in soil water zone, and in groundwater aquifer in a river basin. Using this model, various scenarios of water availability in a river basin can be generated and analyzed. By taking repeated runs of the model for longer time periods, sustainability of various water resources management plans can be examined. The model has been applied to the Upper Bhima basin up to Ujjani dam. Extensive database has been generated for the basin and model runs have been taken from June 1992 to May 2001. Basin data has been used to check the model linkages. Various outputs of the model for the Upper Bhima basin have been discussed in detail. The model results have been checked by matching the river flows at different gauging sites and they have been found to be satisfactory. However, the application has suggested a number of modification requirement in the model some of which include: i) specification of EAC tables for various storage structures, ii) rule-curve based operation of reservoirs so that different management operations can be simulated, iii) option of hydropower simulation of reservoirs, iv) option of spill release to different river segment/sub-basin, v) simpler groundwater representation for river basin planning, vi) option of lift irrigation etc.