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.

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.

Rivers are beneficial to humans due to their multiple functions. However, human meddling substantially degrades the functions of rivers and constitutes a threat to river health. Therefore, it is vital to assess and maintain river function. This study used the Xiaoqing River in Shandong Province, China, as a case study and established a multilayered multifunctional river evaluation indicator system consisting of environmental function, ecological function, social function, and economic function. The weights of indicators were calculated using the analytic hierarchy process (AHP) and the entropy method. Furthermore, a fuzzy comprehensive evaluation model based on the Cauchy distribution function was developed to assess the operation status of each function in each river segment. The results of the indicator and criterion layers in different river sections varied. The multifunctionality of the river decreased from upstream to downstream. The Jinan section was the most multifunctional, followed by the Binzhou, Zibo, and Dongying sections, and finally the Weifang section. Through additional analysis, this study determined the constraint indicators and functions of each river section. Overall, the results reveal that the idea of a “multifunctional river” can advance the theoretical understanding of a river’s function, and the fuzzy comprehensive evaluation model is demonstrated to provide fresh perspectives for evaluating river function.