Health volume of agricultural water consumption and its calculation model in the Heihe River Basin

With competition between agriculture and other industries in the northwest arid areas of China, determination of healthy volume of agricultural water consumption provides the basis for reasonable distribution of available water resources. Based on healthy agricultural water volume connotation and standard, a multi-objective optimization layer calculation model was developed for the northwest arid areas of China. The model achieved its objective function not only for maximum water consumptions in different industries, but also for total water consumption. It also successfully calculated the healthy volumes of agricultural water consumption in different areas under given optimization sequences. The model was successfully tested in calculating healthy volume of agricultural water consumption in the Heihe River Basin (HRB). For different county-level administrative units, the healthy volume of agricultural water consumption was evaluated under different water inflow frequencies for the past (1999), present (2006) and future (2020) years. The results show that model-adjusted water resources allocation in 1999, 2006 and 2020 reduced the basin water volume consumption (in the agricultural and industrial sectors) by 2.7%, 4.6% and 2.1%, respectively. Water benefit was comprehensively increased by 7.1%, 16.6% and 13.1% in 1999, 2006 and 2020, respectively. Similarly, ecological benefit respectively increased by 27.6%, 37.4% and 13.6% in the above periods. Not only was the model reliable, but the feasibility of healthy agricultural water consumption in the region increased. Comparisons of healthy agricultural water consumption among different years revealed that the water situation in the agricultural sector in 2006 was healthier than in 1999. Also the situation in 2020 was healthier than in 2006. While agricultural water use ratios reduced by 3.4% and 2.0%, water efficiency increased by 31.1% and 91.6%, respectively. Based on previous agricultural water distributions, the basin water deficit in 2020 was predicted at 10.6%, 13.8% and 25.9% under 50%, 75% and 95% of water inflow frequencies. It showed higher scarcity of water resources then. It was concluded that in order to meaningfully curb water shortage, water resources allocation should be adjusted based on healthy volumes of agricultural water consumption.