Purpose. This study aims to quantify the water resources change, identify the main challenges and provide management suggestions in the water-stressed Yellow River Basin under the changing environment.
Key issues. Under the impacts of climate change and strong human activities, the water resources situation in the Yellow River Basin (795000 km2) has greatly changed. The existing main issues include: 1) the annual average runoff at the Tongguan gauge station since 2010 has decreased by 34% compared with that from 1919 to 1959, and the sediment has decreased by 94%; 2) the continuously-increased socio-economic water use has caused insufficient environment flow in rivers and groundwater overexploitation; 3) the urbanization progress since 1980s has led to urban inundation and water quality deterioration problems. It is highly desired to quantify and attribute the water resources decrease and to study the adaptive strategies of water resources management.
Methodology. The distributed hydrology model WEP with combinations of statistical analysis of hydro-meteorological data and remote-sensing data are adopted to address the above-mentioned issues. Both natural hydrological processes and water utilization processes are depicted in the model, and the observed flow series at main gauge stations are used to validate the model.
Results. The study results show that climate variation, soil conservation and water use facilities are main reasons for the water resources decrease in the basin, and six rules of water resources evolution are summarized, including surface water and groundwater change, and blue water (runoff of surface water and groundwater) and green water (utilized by ecosystem) etc. An interesting finding is the groundwater resources unrepeated with the surface water resources has obviously increased contrasting to the obvious decrease of surface water resources. Adaptive strategies for ensuring water resources security in the basin are suggested from the aspects of comprehensive water-saving, ecological sponge watershed construction, optimal water resources allocation, and legislation-institution arrangements including updating water rights allocation, water pricing, environmental flow guarantee mechanism etc.
Results implications. The study is believed to be of a referential value for policy-making in the water management in the Yellow River basin under the changing environment.