The evaluation of regional water-saving level can provide scientific theoretical support for steadily promoting the implementation of a national water-saving priority strategy. Referring to the water consumption statistics of 31 provinces (except Hong Kong, Macao and Taiwan) in China in 2018, 14 easily accessible and comprehensive indexes were selected to establish an index system of regional water-saving level and a water-saving level evaluation model based on support vector machine optimized by genetic algorithm (GA-SVM) was constructed to analyze the national regional water-saving level from different perspectives. The results showed that the water-saving level in China presented a spatial distribution characteristic with Beijing City, Henan Province and Zhejiang Province as the center and gradually decreased outward. From the perspective of regionalization, the water-saving level in North China, Central China and Southeast China was higher, while the water-saving level in Northwest China, Southwest China and Northeast China need to be improved. Therefore, the national water-saving level is generally at a medium level and effective water-saving work and water-saving schemes should be carried out according to different regions and industries.

Lakes in arid inland areas are important indicators for reflecting the regional ecosystem security under climate change and human-related impacts. Understanding the evolution characteristics of lakes is helpful for eco-environment protection and management. This study applied the Landsat remote sensing data from 2002 to 2017 to analyze the water surface area changes of East Juyan Lake, a closed lake in northwest China. The results showed that the upward trends existed from 2002 to 2006 and were more significant from 2014 to 2017. The upward trends became gentle from 2007 to 2013. Regarding the seasonal characteristics, the water surface area in winter was almost the largest in the whole year, with an annual average of 51km2, followed by that in autumn (50.45km2). The annual average value in spring (48.16km2) was larger than that in summer (41km2). For the spatial changes, the lake boundary generally expanded from 2002 to 2009, and its eastern and western boundaries changed obviously after 2006. After 2010, the changes in lake boundaries tended to be gentle.

The commonly used calculation and prediction methods of mine water inflow in China are divided into deterministic and non-deterministic. Affected by many influencing factors, the applicability of the calculation method has not been reflected, resulting in a large prediction error. By combing the main influencing factors of mine water inflow, The characteristics, advantages, and limitations of evaluation prediction methods, Clarify the selection of the three-stage prediction methods in the exploration phase, well development phase, and mining phase, Establishing a framework for the principles and prediction process framework of mine water inflow forecasting, Achieve precise forecasting and reduce the risk of approval of water resources demonstration by management departments, Helps to turn mine water into waste and improve the management of comprehensive utilization of mine water, Realize the integration of unconventional water resources into the unified allocation of water resources, alleviate the conflict between supply and demand of water resources, and improve the efficiency and utilization efficiency of regional water resources allocation.