Taking the Yangtze River Source Basin (YRSB) and Shule River Basin (SRB) as two typical cases, the sustainability of the water resources in these two basins was evaluated using the level of water stress (LWS) from sustainable development goal 6.4.2, and the regulating effect of the glacier runoff on the LWS was quantified. From 2000 to 2030, the level of socioeconomic development in the YRSB is low, and the total water consumption is only about 0.18 x 10(8) m(3), whereas the SRB has a relatively high level of socioeconomic development and total water consumption is about 10 x 10(8) m(3), i.e., 50 times higher than that in the YRSB. For the aforementioned reasons, the SRB's LWS is much higher than the YRSB's, resulting in a very low sustainability of water resources. As natural assets, glaciers flow downstream in the runoff mode, so compensation at the watershed scale should be considered. In the basin, the optimal allocation of water resources is needed. At the inter-basin scale, the compensation mechanism of glacier water resources needs to be improved.

The rational allocation of the water resources in drylands and the scientific evaluation of their values are important for the regional sustainable development. We estimated the water consumption of each ecosystem in Ejina Oases in the arid area in northwest China based on the water balance equation, then assessed their ecosystem service values (ESVs) using the value per unit area method and the value equivalent factor per unit area method considering the cost of water consumption, respectively, and calculated their water productivities from 1990 to 2015. With the implementation of the ecological water diversion project (EWDP) in 2000, the deciduous broadleaf forest dominated by Populus euphratica had an increasing trend, meanwhile, lakes had a changing process from shrinking and drying up to recovery and expansion from 1990 to 2015. The total water consumption in Ejina Oases decreased from 5.26*10(8) m(3) in 1990 to 4.79*10(8) m(3) in 2000, and then increased continually to 5.97*10(8) m(3) in 2015. The water consumption of forest, grassland and cultivated land hardly changed, while the water consumption of water or wetland changed obviously. The total ESVs estimated using the value per unit area method in Ejina Oases decreased from 1052.6 to 787.3 million yen in the period of 1990-2000, then increased to 1500.6 million yen in 2015, while the ESVs estimated using the value equivalent factor per unit area method decreased from 6368.7 million yen in 1990 to 5892.0 million yen in 2000, then increased to 7139.9 million yen in 2015, and the latter method was more reasonable. The results showed that the EWDP started in 2000 led to the reallocation of water resources and transfer of ESVs among ecosystems, which had obvious performance in the ecological environment and social economy. This study provided a comprehensive view of water use and management, ecological restoration and socio-economic development in this key ecological function zone, and will help decision-makers to formulate the scheme of rational allocation and efficient utilization of water resources in the basin.