Analysis and emergy assessment of the eco-environmental benefits of rivers

The assessment of the eco-environmental benefits of rivers has important guiding significance for improving water resource management, establishing water resource protection mechanisms, and maintaining river health. In view of the current imprecise quantitative methods of determining the eco-environmental benefits of rivers and based on the viewpoint of ecology, the significance and composition of river eco-environmental benefits were discussed. An emergy theory was introduced to quantify both the solar transformity of subtypes of water bodies and the sediment transportation benefit, which improved the indicator system of eco-environmental benefits. Applying the indicator system to the management practice of the Yellow River Basin, the eco-environmental benefits in 2015 were calculated by dividing the Yellow River into 66 sections. A Geographic Information System (GIS) atlas was then used to describe their spatial distribution. Eight typical cities were selected for the key analysis. Among these eight cities, the eco-environmental benefit inside the river in Xi'an section is the largest with a total emergy benefit of 1.08 x 10(21) solar equivalent joules (sej) and a corresponding monetary benefit of 28.03 Chinese Yuan ((sic))/m(3). The eco-environmental benefit outside the river in Jinan section is the largest with a total emergy benefit of 1.37 x 10(20) sej and a corresponding monetary benefit of 12.39 (sic)/m(3). This study proposed that rivers have great eco-environmental benefits, and the harmonious development of economy, society, and environment should be pursued in water resources management.