Water efficiency evaluation of a regional water scheme – Zhengzhou, China, using a water ecological–economic system (WEES) and based on emergy theory

Abstract

With the rapid development of society and the economy, the shortage of water resources and the deterioration of the water environment has resulted in restriction of the development of society and the protection of ecology and the environment. Consequently improving water efficiency is the key to realizing the sustainable utilization of water resources, and water efficiency evaluation is an important part of water resources management. Emergy theory aims to convert different dimensions of material and energy into solar energy, which can be analyzed and compared uniformly. Therefore, a new approach to assessing the economic efficiency of water resources, based on the water contribution to economic production, is evaluated using an emergy theory model. Water efficiency and system sustainability are explained by variables and emergy indicators in a regional water ecological–economic system (WEES) for Zhengzhou, China. The general status and economic efficiency of water resources in Zhengzhou are identified from the WEES. The average water contribution quantity and water contribution rate were 50.99 × 1020 sej and 6.13% during 2000–2011, respectively. Results also show that industrial water efficiency is higher than that of agriculture. This quantification method will help decision-makers to adjust water prices and provide better water services.