Eco-efficiency evaluation of the water conservancy and hydropower project based on emergy analysis theory

The positive and negative effects of the water conservancy and hydropower projects are analyzed based on the emergy analysis theory. The indexes content of emergy yield ratio (EYR) and environment load ratio (ELR) are redefined. In order to analyze the ecological effects quantitatively, hydraulic eco efficiency index (HEI) is proposed to reflect its sustainable development performance. Case study shows that among the positive effects of Chinese water conservancy and hydropower engineering, hydropower, flood adjustment, water supply for industry, water supply for agriculture irrigation is the main contribution, accounting for 21.3%, 26.6%, 21.6% and 21.4%, respectively (2008). Both EYR and HEI show a downward trend, but the ELR is rising. These trends show that the ecological pressure on the environment is growing, although the water conservancy and hydropower project supply the positive effect output to us.