Risk assessment and optimization of water resources shortage based on water and land resources coupling

Abstract: Water resources risk assessment is a premise of protecting the development of industry and agriculture in Heilongjiang Province. Land resources combined with water resources affect the agricultural and industrial development. However, few studies have link both together in water resource studies. In this paper, we assessed water shortage risk and found the optimization paths of water resources based on coupling of water and land resources in Heilongjiang Province and its 13 prefecture-level cities. Four criteria layers with 17 indicators including water resources endowment, social economy, water utilization and water environment were established as a risk assessment index system of water shortage in the study area. Objective empowerment entropy method was used to determine the weight of each evaluation index in order to avoid the inaccuracy of subjective assumptions. The risk of water resources shortage evaluated by matter-element model was divided into 5 levels: Grade I (low risk), Grade II (lower risk), Grade III (medium risk), Grade IV (higher risk) and Grade V (high risk) grade. Then, the driving force of water shortage risk was analyzed by using the logarithmic mean Divisa index (LMDI) model, and the mean value of water consumption from 2010 to 2014 in Heilongjiang Province was adopted as the reference, and the difference between the water consumption of each criterion and the reference water consumption in 2010-2014 was calculated and summarized. Decomposition model of water utilization variation was constructed. Results showed that the comprehensive correlation degree of the total water shortage in Heilongjiang Province was 0.03, belonging to Grade III (medium risk). The risk of water shortage in the 13 prefecture-level cities showed great spatial differences, which was characterized as low risk in the north and south and high in the east and west of the Heilongjiang. The water shortage risk belonged to Grade V in the Daqing, Hegang, Jiamusi and Shuangyashan, Grade IV in the Qiqihar and Mudanjiang, Grade III in Suihua, Yichun and Harbin, Grade I in the Daxinganling and Heihe. The main influencing factors of the high risk of water shortage included water yielding coefficient, water investment per unit area for agriculture and forestry, water consumption per million RMB, per capita water requirement, irrigation rate of cultivated land and discharge rate of sewage treatment, which should be significantly considered in finding solutions to water shortage. The LMDI showed that the social economy and water utilization were the main factors influencing the grade of water shortage risk. Then, the coupling degree of the respective sub-elements of water and land resources was evaluated by the coupled coordination model, and it was concluded that the coupling degree of land and water resources in Heilongjiang Province was at the moderate level of antagonistic coupling, and the land resources development lagged behind slightly. Meanwhile, the lagging factors of these regions were analyzed from the aspects of social economy and water and land utilization. Based on the evaluation of water shortage risk, the analysis of driving factors and the coupling analysis of water and land resources, the double optimization path of water shortage with both economic orientation and resource orientation was selected. According to the specific problems of different risk areas, advices on specific solution were put forward to promote effective coupling of water and land resources and to find an effective way to alleviate water shortage. As the continuous development of economy and society, regional resource endowments and risk characteristics should be combined to formulate a scientific and rational scheme on water utilization.