China’s water sustainability in the 21st century: a climate-informed water risk assessment covering multi-sector water demands

摘要

China is facing a water resources crisis with grow- ing concerns as to the reliable supply of water for agricul-tural, industrial and domestic needs. High inter-annual rain-fall variability and increasing consumptive use across the country exacerbates the situation further and is a constraint on future development. For water sustainability, it is neces-sary to examine the differences in water demand and supply and their spatio-temporal distribution in order to quantify the dimensions of the water risk. Here, a detailed quantitative assessment of water risk as measured by the spatial distribu-tion of cumulated de?cits for China is presented. Consider-ing daily precipitation and temperature variability over ?fty years and the current water demands, risk measures are de-veloped to inform county level water de?cits that account for both within-year and across-year variations in climate. We choose political rather than watershed boundaries since eco-nomic activity and water use are organized by county and the political process is best informed through that unit. As ex-pected, the risk measures highlight North China Plain coun-ties as highly water stressed. Regions with high water stress have high inter-annual variability in rainfall and now have depleted groundwater aquifers. The stress components due to agricultural, industrial and domestic water demands are illustrated separately to assess the vulnerability of particu-lar sectors within the country to provide a basis for targeted policy analysis for reducing water stress.