Models for water resources assessment and reservoir operation simulation in a multi-basin system

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. A conceptual spatially distributed water balance model has been developed to simulate various components of the hydrologic cycle at the scale of a river basin. In this model, focus is given to incorporate the spatial variation of land use, soil type, rainfall, evapo-transpiration, physiographic characteristics, groundwater conditions, river network and hydraulic structures in a river basin. GIS is employed to link the spatial data with the simulation model and to project the model results in map form for easy visualization. The basin is divided into grid cells of uniform size (~1 km) and the model computes various components of hydrologic cycle such as actual crop evapotranspiration, overland flow, groundwater recharge, and residual soil water content at weekly time step for each grid cell. 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. In addition, another model named ‘NIH_ReSyP’ has been developed for the simulation of a multi-purpose multi-reservoir system, spread across many basins, for conservation and flood control purposes. By taking repeated runs of reservoir simulation model for different scenarios of water availability and demands, reliability and sustainability of various water resources management plans can be examined.