Gauge observed runoff can reflect influences of both natural hydrological cycle and human intervention. The Global Land Data Assimilation System (GLDAS) 2.0 and 2.1 provide abundant runoff which are useful for water resources assessment in ungauged/poorly gauged regions. However, GLDAS2.0 and GLDAS2.1 runoff have only been validated and inter‐compared in very limited regions. In this study, they are evaluated and inter‐compared utilizing gauge observation in 11 large river basins in China. Results show their runoff have large uncertainties: absolute values of relative bias (|RB|) being above 39% and Nash‐Sutcliffe efficiency lower than 0.15 on average, but GLDAS2.1 is better. Both of them have large uncertainty in the Tibetan Plateau:|RB|are higher than 40%. The gap between GLDAS runoff and observations could attribute to both GLDAS system uncertainty and the fact that GLDAS does not consider human intervention. Therefore, cautions should be taken when using them in coupled human‐natural systems.

With the rapid socio-economic development, human disturbances are believed to have resulted in the degradation of the watershed ecosystem. The ecological damage to and environmental pollution of river basins have caused great losses. It is widely agreed upon that the protection and restoration of river ecosystems should be on the agenda. Ecological compensation, an important tool to prevent the deterioration of water environments and achieve sustainable watershed development, has attracted increasing interest as a research subject. In this study, the upper reach of Hun River basin was selected as a typical study area. The primary purpose was to determine the allocation costs of ecological compensation in different regions for the river basin. The amount of willingness-to-pay (WTP) for the eco-compensation was estimated at 3.2 million dollars by the Contingent Valuation Method (CVM). Based on linear programming techniques, a Data Envelopment Analysis (DEA) created a primary value of the allocation costs. Considering the different weights of each region, a modified coefficient was introduced to correct the primary result on the basis of a questionnaire survey of river ecological protection and construction.

Groundwater recharge from rainstorms can be vital for regional water resources. With the expansion of the need for more water in some specific regions under global climate change, groundwater is being pumped at a far greater rate than it can be naturally replenished. Considering that excess rainstorms could be utilized for groundwater recharge to lessen the declining tendency of regional groundwater level in the Sanjiang Plain, Northeast China, we analyzed groundwater changes in the quantity of a regional shallow aquifer in the region following extreme rainfall in 2013. The results show that shallow groundwater table in the north and central Sanjiang Plain increased following the 2013 extreme rainfall. Most of the annual maximal change of groundwater depth (MCGD) was in the range of 1 m to 3 m, occupying 72.1% of the study area. The average MCGD was 1.73 m in 2013, about 0.4 m higher than the mean value during the last five years (1.33 m). Spatially, the overall average groundwater depth showed an increasing trend from the southeast to the midwest and northeast. We estimated a total recharge of approximately 41.14 × 10⁸ m³ from the 2013 extreme rainfall across the north and central Sanjiang Plain. This large quantity of recharge demonstrates the important role that large rainstorms can play in regional shallow groundwater resources.

Natural rivers have been disturbed for hundreds of years by human activities. Previous water conservancy projects in the form of dams, reservoirs, dykes, and irrigation infrastructure focused on the social and economic benefits and disregarded the adverse effects on the physical, chemical, and biological characteristics of the affected rivers. Since the 2000s, the comprehension of river remolding has transformed so decisions are more socially and ecologically beneficial. However, restoration actions are often implemented aimlessly, without a detailed plan or sufficient communication, leading to the failure of accomplishing objectives for a variety of ecologic, financial, and social reasons. Thus, a pre-assessment framework is proposed in this paper, to determine river restoration priorities, emphasizing both social and ecological aspects. The vague notion of river health is evaluated using the Variable Fuzzy Assessment Model (VFAM) and expressed by modified Nightingale Rose Diagrams (NRDs). The river social ecosystem was subsequently analysed using this framework in the Ashihe River near Harbin City, Northeast China. The application of VFAM demonstrated that the health status of the upper, middle, and lower sections of the river could be classified as sub-healthy, degraded, or sick in terms of ecosystem structures, and sub-healthy, degraded, or degraded in terms of social functions, respectively. The health status of the lower section was the poorest and should be restored first. Using NRDs, we found that water quality deterioration and irrigation works are the two key factors in river degradation, which must be improved throughout the entire watershed. Aesthetics and recreation should also be given priority to restore the lower section due to the demands of nearby residents. Several measures are also suggested for decision makers who need a more detailed design to implement. This framework potentially assists with communicating with stakeholders, avoids aimless restoration actions, and contributes to comparing with the measuring after restorations.