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The impacts of climate change and human activity, combined with streamflow reduction in the Yellow River Basin, have presented significant challenges to water resource management strategies. Here, the trends and change points of streamflow were determined for the period 1956–2017 via five statistical methods. A runoff-sensitive coefficients method (the Budyko hypothesis) and a conceptual rainfall–runoff model (the TUW model) were applied to assess the streamflow variation. The following conclusions were ascertained: (1) 1989, 1986, and 1990 were the change points for streamflow in the upstream Tang-Nai-Hai and Lan-Zhou stations and the downstream Hua-Yuan-Kou hydrological station; (2) the streamflow showed statistically significant decreasing trends with spatiotemporal variations in the Yellow River Basin; (3) the relationship between runoff and precipitation showed a downward trend over time; (4) comparisons of the Budyko and TUW models show that human activity is responsible for more than 65% of streamflow reduction, while climate change contributes to less than 35% of the reduction. Therefore, human activity is the main reason for streamflow reduction in the Yellow River Basin. This finding is of critical importance for water resources management under changing environment.

Limited water resources and rapid socioeconomic development pose new challenges to watershed water resource management. By integrating the perspectives of stakeholders and decision-makers, this study aims to identify cases and approaches to achieve sustainable water resources management. It improves and expands the experience of previous project research. The comparative evaluation provides an analytical basis to verify the importance of stakeholder participation in water policy interactions. The results show that if an effective demand management policy is not implemented, the Guanzhong area will not meet water demand in the future. Through the combination of water-saving policies, water transfer projects and other measures, the available water resources will continue into the future. Optimizing management measures, improving the ecological environment, and encouraging stakeholder participation will help change this situation, although supply-side limitations and future uncertainties likely cause unsustainable water. Therefore, decision-makers should pay attention to the application potential of water-saving and other measures to reduce dependence on external water sources. In addition, the three sustainable development decision-making principles identified in this paper can promote the fairness and stability of water policy.

Groundwater, the most important water resource and the largest distributed store of fresh water in the world, supports sustainability of groundwater-dependent ecosystems and resilient and sustainable economy of the future. However, groundwater level decline in many parts of world has occurred as a result of a combination of climate change, land cover change and groundwater abstraction from aquifers. This study investigates the determination of the contributions of these factors to the groundwater level changes with the HydroSight model. The unconfined superficial aquifer in the Gnangara region in Western Australia was used as a case study. It was found that rainfall dominates long-term (1992–2014) groundwater level changes and the contribution rate of rainfall reduced because the rainfall decreased over time. The mean rainfall contribution rate is 77% for climate and land cover analysis and 90% for climate and pumping analysis. Secondly, the increasing groundwater pumping activities had a significant influence on groundwater level and its mean contribution rate on groundwater level decline is -23%. The land cover changes had limited influence on long-term groundwater level changes and the contribution rate is stable over time with a mean of 2%. Results also showed spatial heterogeneity: the groundwater level changes were mainly influenced by rainfall and groundwater pumping in the southern study region, and the groundwater level changes were influenced by the combination of rainfall, land cover and groundwater pumping in the northern study region. This research will assist in developing a quantitative understanding of the influences of different factors on groundwater level changes in any aquifer in the world.