Optimal allocation and application of water resources based on real water saving in a region with intensive human activity.

As water demand continues to grow, water resource management that only restricts water withdrawal can no longer ensure sustainable water use, especially in region with intensive human activities. In the water cycle of precipitation, runoff and evapotranspiration at the basin scale, only water evapotranspiration is the actual consumption of water. Water resource management that aims to control the total consumption within a basin is referred to as "real water saving," which can prevent the depletion of water resources. Based on the real water saving, we evaluate the water consumption in the base year (2018) and the planned year (2030) of Ziya River Basin, a basin with intensive human activities, by SWAT model and quota method. Under the 50% guarantee rate, the total available water consumption is 25.13 billion m, while the actual water consumption exceeds it by 0.91 billion m in the base year and by 1.92 billion m in the planned year, respectively. The excess is met by over-pumping of groundwater. Therefore, we propose a new method to incorporate the real water saving into the water resource optimization allocation model, which aims to reduce the total water consumption, and also considers promoting the coordination of industrial structure and regional water use equity. The results show that the actual ET reduction potential was 916 million m. However, to achieve the water balance and sustainable development, the middle route of the South-to-North Water Transfer Project needs to increase the water transfer to Ziya River Basin by 1.58 billion m. And we put forward some concrete management strategies, including setting the red line of water consumption, raising the water transfer index and reducing the irrigation water. This study provides a sustainable management model and strategies for water resources management in intensive human activity region, which is conducive to improve the water resources management system and realize the sustainable development of the basin.