Change law and cause analysis of water resources and water consumption in China in past 20 years

The water resources have become one of the main factors restricting the economic and social development of our country. The water safety has become one of the strategic issues of the national security, and especially in recent years, the shortage of the water resources and other related issues have aggravated the situation of the water safety. Based on the data of the water resources and water consumption from the ten first-class water resources regions in China from 1997 to 2016, the Mann-Kendall and Theil-Sen testing methods are used to test the significance of the data. The Kendall-gradient is used to characterize the time series variation characteristics of each factor. The characteristics and regularities of the water resources and water consumption change in China are revealed on the space-time scales. The analysis results indicate that the total amount of the water resources in China has not decreased significantly in the past 20 years. The total amount of the water resources in the northern China has not increased significantly, and the total amount of the water resources in the southern China has not decreased significantly. China's total water consumption has increased significantly. Except the increase of agricultural water consumption is not obvious, the water consumption of other industries has shown a significant growth trend, especially the increase of the domestic water consumption is the most obvious. The change characteristics of the total amount of the water resources in the adjacent regions of the ten first-class water resources regions are similar, and the change characteristics in different regions show special heterogeneity. Compared with the leading level of the water resources utilization in the developed countries, China's agricultural water-saving potential is great.