Evaluation of water resources utilization in Guizhou Province based on water footprint theory and LMDI model

Guizhou Province is located in southwest China with a total land area of about 176,000 km2, accounting for 1.8% of the China’s land area. Karst landforms are widely distributed in this region with a large area of peak-clusters and depressions, forming a unique karst ecosystem. This region has subtropical humid monsoon climate, featured by notable spatial and temporal differences of precipitation. As a typical karst region, it has water resource vulnerability, manifested by low water storage capacity, frequent seasonal drought, and the water environment is easily polluted and difficult to recover. In recent years, the engineering water shortage problem has been significantly improved with the comprehensive progress of large-scale water source project construction in Guizhou Province. In order to evaluate current situation of water resources utilization and the driving factors affecting water use in Guizhou Province, this work established a water resources utilization evaluation index system, based on the water footprint theory; and the analysis of temporal changes of the water footprints from 2000 to 2017 was carried out. The LMDI model was used to examine the impact extent of population, economic and technological driving factors on the changes of the water footprints. The results show that the total water footprint of Guizhou Province has experienced a process of growth from fluctuant to decreasing one and then gradually increase. The self-sufficiency rate of water resources is more than 97% per year, and the degree of external dependence is low; the economic benefit value of water footprints increases year by year. Water footprint land density is consistent with the trend of total water footprint. However, the population density of 10,000 tons of water footprint is inconsistent with the trend of total water footprint. The overall pressure index of water resources is maintained above 40%, of which the water stress index of semi-dry and dry years is greater than 70%. Based on the LMDI model, the impact degree of anthropogenic driving factors on the changes of water footprint, is in the order of economic effect>technical effect>population effects. Among them, economic effects account for 53.22% of the impact, while technical effects contribute 46.1% and population effects are only 0.68%. Precipitation as a main natural driving factor is also leading the changes in water footprint.