Oasis sustainability is related to water supply mode

Oasis development relies on water supply and the supply mode can be divided into artesian piloting water (APW) mode and high-lift pumping water (HPW) mode. APW mode relies on gravity to retain and intercept water. HPW mode uses cascade pumping irrigation projects to transport water by up to 470 m, mainly serving extremely arid areas. A comprehensive analysis of the water-energy-food-ecology (WEFE) nexus to optimize water use management is conducive to the sustainable development of an oasis. Due to differences in water supply difficulty and cost, there are significant differences in socioeconomic development, water management, and drought adaptation between the APW and HPW oases. Taking the APW and HPW regions of Ningxia in the Yellow River Basin as the study areas, this study constructed a Bayesian network (BN) to quantify the causality and uncertainty in the WEFE nexus to analyze the development status and the evolving characteristics of the human-water relationships of the two regions. Scenario simulation based on BN quantified the impact and difference of management measures on the WEFE nexus in the two regions. During 2000-2020, as the APW region developed, agricultural water use decreased by 36%, showing great water-saving potential, while the development of the HPW region experienced water shortages. Excessive and inefficient agricultural water use is the main factor affecting the sustainability in both regions. Improving irrigation coefficient is the most effective way to reduce agricultural water use, and there is still a large adjustment space in agricultural water prices, channel lining rates and drip irrigation popularization areas to improve this coefficient. The adjustment of the planting structure will have great water-saving potential in the APW region, such as reducing rice area to 20,000 ha will save 5 x 108 m3 of water, but the potential is limited in the HPW area dominated by drought-resistant crops. In addition, improving wastewater treatment and ecological water use will effectively improve surface water quality and the ecological environment in the APW and HPW regions.