干旱区生态环境知识资源中心

The scientific understanding of hydro-meteorological and agricultural changes in the water-scarce region is crucial to formulate a plan for sustainable management of water resources and cropping pattern under the scenario of climate change. The present investigation, therefore, has attempted to detect the trends in the monsoon rainfall, runoff, dam storage, post-monsoon groundwater (PMGW) levels, and agricultural data in the Karha Basin, located in the rain shadow zone of the Western Ghat. Additionally, trends in projected monsoon rainfall and average annual temperature were also analyzed. The study indicates no significant increase in monsoon rainfall over the basin during past (1981-2013) and future (2015-2050). The noteworthy decline in monsoon runoff has mainly resulted due to the effective implementation of surface water harvesting in the basin, which has a significant positive change in PMGW table in the basin. The study also provides evidence of the shift in agricultural pattern, where the rainfed crops are getting replaced by the high water-requiring/cash crops. It may increase the future agricultural water demand and pressurize the limited water resources in the basin. On the other hand, significant increase in near-term future (up to 2050) temperature can augment the water demand along with the adverse impacts on the agricultural productivity. The Karha Basin is already suffering from water deficiency. The man-induced increase in agricultural water demand and the adverse climatic changes in the Karha Basin are very likely to aggravate the future drought conditions and further add to an already difficult water management challenge in the basin.