Abstract:
India is an agrarian country where more than seventy percent of population depends largely on agriculture and agro related business. The projected scenarios of precipitation from climate models predict decrease in some region and increase in others, albeit with large uncertainty in most of the places. The Chhattisgarh state which is called rice bowl of India has number of water resources projects where climate change can change crop water requirement. The present study has been carried out in the command of Tandula reservoir using statistical downscaling of climatic parameters for computation of crop water requirement using RCP2.6, RCP4.5 and RCP8.5 scenarios of coupled model inter-comparison project 5 (CMIP5). For calibration and validation, twenty six NCEP resealed climatic variables from 1971 to 2003 have been used with minimum and maximum temperature and rainfall for concurrent period. The percentage reduction and k-fold cross validation techniques have been used for selection of best suited climatic parameters for statistical downscaling and used to generate multiple ensembles of temperature and rainfall for three future assessment periods namely i.e. near century period as FP-1 (2020-35), mid century period as FP-2 (2046-64) and far century period as FP-3 (2081-99). The projected multiple series of climatic variables were further used to compute evapotranspiration using CLIMWAT and then crop water requirement in the command and compared with corresponding requirement during the base period (BP: 1971 to 2014). The results of analysis suggested that the mean monthly maximum temperature showed a rising trend in all the months, while significant increase of minimum temperature during winter and rainy season. The average crop water requirement for designed cropping pattern of 82089 ha of kharif paddy during base period under present overall efficiency of 51% during base period may be about 473.7 Mm3 will increase to 479.0 Mm3 during near century period (2020-35), 492.7 Mm3 during mid century period and reduce to 387.9 Mm3 during far century period (2018-99). The midcentury period may be the most critical among all and it is recommended to develop adaptation measures to combat climate change especially in mid-century period.
