Sustainability assessment in the anthropocentric watershed based on emergy and decomposition methods: A case study of Erhai Lake Basin, southwest China

Abstract

Assessment of anthropocentric watersheds’ sustainability and its driving forces is important for regional natural resources management and sustainable development. However, the impact of natural resources use on watersheds’ sustainability needs deeper exploration. This study employs emergy accounting and decomposition analysis methods to evaluate the sustainability and related key factors of Erhai Lake Basin (ELB) of Yunnan province in China -- a watershed facing urgently sustainable issues. Major results show that the environmental sustainability index (ESI) of ELB decreased with low production efficiency -- emergy yield ratio (EYR), and high environmental pressure -- environmental loading ratio (ELR) from 2000 to 2015. Four factors within the decomposition analysis have been identified, namely the emergy intensity factor (ΔUG), resource factor (ΔRF), water supporting factor (ΔWN) and water efficiency factor (ΔPW), as the major drivers of ESI changes. The economic development in ELB highly exceeded the carrying capacity of natural water resources, relying on imported resources and, in so doing, affecting sustainability levels. Accordingly, several suggestions are proposed which are helpful for sustainable watersheds governance.