Impact of Climate Change on the Availability of Virtual Water Estimated with the Help of Distributed Neurogenetic Models

Abstract

Impact of climate change on virtual water of a tropical multireservoir system was estimated with the help of models developed by neural network and genetic algorithm. Virtual water or embedded water or embodied water, or hidden water refers to the water used in the production of goods or services. For instance, it takes 1,300 m3 of water on an average to produce 1 t of wheat. The precise volume can be more or less depending on climatic conditions and agricultural practice. The virtual water has major impacts on productive use of water and global trade policy especially in water-scarce regions. The impact of climate change on virtual water could open a path for the efficient use of virtual water in the face of climatic uncertainties, which may directly impact availability of raw water. The present study tried to estimate the future virtual water with the help of neurogenetic models, which estimates stream flow as function of various hydrological, meterological variables, and basin characteristics. The models prepared were distributed in nature and also consider temporal variability. In total, two models were prepared with rainfall, time of concentration, and catchment loss as input and stream flow as output. One model was prepared by classifying the dataset, based on the magnitude of the variable, and the other model was prepared with normal dataset. First, the better performing model was identified and then output from RCM-PRECIS model was applied to the chosen model to estimate the impact of climate change on stream flow. The estimation results were used to calculate the amount of virtual water, and the result was compared with the present-day virtual water to analyze the change in virtual water availability due to climate change. According to the results, model prepared with normal dataset was identified as a better model, and from the estimations it could be concluded that virtual water availability would increase in case of both A2 and B2 scenario of climate change where the change would be more pronounced in case of the latter.