A multiple criteria decision-making approach for water allocation of environmental flows considering the value trade-offs - A case study of Fen River in China.

In the water-scarce basin, the allocation of environmental flows needs to achieve the equilibrium between ecological protection and economic development. One of the challenges is the lack of quantitative analysis of the value of water in the economy and ecosystem, which could not effectively support the decision-making. This paper proposed a new multi-criteria decision-making approach that considers the value trade-offs between the environmental flows and the economic water use of rivers. The value of environmental flows was assessed using the modified equivalent factor method combined with the hydraulic method, which considers the influences of the hydraulic characteristics of rivers on value assessment. The value of the economic water use was estimated using the modified Cobb-Douglas production function. The ideal point method was applied to obtain the optimal solution of the multi-criteria decision with the objective of maximum values of the economic water use and maximum values of environmental flows (or the value of multiple recommended environmental flows). This new method was applied to determine the optimal environmental flows in the Fen River, the second-largest tributary of the Yellow River of China. The results indicated that the reasonable environmental flows were 51.1 % or 40.4 % (considering the water shortage for development) of the natural runoff of the Fen River. This work could provide a valuable reference for determining the water allocation of environmental flows in the water shortage area of China.

Health risk assessment of phreatic water based on triangular fuzzy theory in Yinchuan plain.

Groundwater quality relating closely to human health has become a great concern to the whole society, especially in heavily polluted areas. Yinchuan Plain, located in the arid and semi-arid region of Northwestern China, where people rely heavily on groundwater resource. However, due to the improper groundwater exploitation and negative effect of human activities in recent years, groundwater quality in Yinchuan plain become deteriorated. For the sustainable utilization and protection of groundwater resources, health risk assessment (HRA) of phreatic water is conducted in this paper. On the basis of model recommended by EPA, triangular fuzzy number is applied to establish risk assessment model for health risk assessment of adults and children in wet and dry seasons, respectively. Results of HRA indicate that carcinogenic risk of arsenic is highest among the risk from components in phreatic water, and the highest risk from arsenic to adults and children in wet and dry season are 6.48 × 10-6a-1 and 9.56 × 10-6a-1, 1.08 × 10-5a-1 and 1.59 × 10-5a-1, respectively. This study also states that in Yinchuan Plain carcinogenic risk from drinking groundwater can be 3-4 times magnitude higher than the noncarcinogenic risk. Also it is found that the health risk to children is as 1.5-2 times as to adults, while the uncertainties of adults' health risk are higher than that of children.