A Bayesian network approach for determining optimal ecological base flow of rivers in water shortage areas of Northwest China

How to balance natural river base flow with water loss from agricultural activities such as irrigation has become an important global challenge in areas of water shortage. Using a Bayesian network model, we constructed a decision-making framework for river ecological base flow in the water shortage areas. This framework can be divided into three components: (1) calculation of economic losses caused when priority is given to protect river ecological base flow, (2) construction of a decision-making Bayesian network, and (3) determination of an optimum ecological base flow of rivers based on an acceptable probability of acceptable economic losses the decision-makers selected. We used the Baoji section of the Weihe River as a typical water shortage area case study. The results show that the optimum ecological base flows in the Baoji section of Weihe River in wet, normal, and dry years were 32.35%, 20.59%, and 14.71% of natural inflow in rivers, respectively. From an economic benefit perspective, the beneficiaries should provide more financial support to protect the ecological base flow of rivers. Our approach could be used in other water shortage areas where decisions need to be made between protection of river ecological base flows of rivers and agricultural use.