Comprehensive analysis of water resources from the perspective of water footprint and water ecological footprint: a case study from Anyang City, China.

Abstract

Agriculture is the largest freshwater consumer, accounting for ~ 70% of global freshwater consumption. The agricultural water footprint (WF) and water resources ecological footprint (EFw) are used to describe the ecological environment and socioeconomic functions of water resources. Anyang in the North China Plain is a typical area with freshwater shortage and was selected as a study area to estimate water consumption by agriculture. We estimated the spatiotemporal variation of green, blue, and grey WF of five crops in Anyang during 1990-2018 based on the WF theory, EFw, and water resources carrying capacity (ECw) methods. To analyze the EFw of specific crops, we developed the framework between agricultural WF and EFw, and quantified the EFw of specific crops. The results show that the WFgreen, WFblue, and WFgrey of Anyang increased from 1188, 1560, and 511 million m3 in 1990 to 1440, 1736, and 1010 million m3 in 2018, respectively, mainly owing to the increase of cultivated area and amount of agricultural nitrogen. Winter wheat and maize were the two leading crops in both green and blue water consumption, taking 31.35 and 55.25% of the total WFgreen, and 71.32 and 22.52% of the total WFblue, respectively. The average unit mass WFgreen and WFblue of crops showed a reducing trend during 1990-2018 because of the urbanization of farmland and the increase of crop yields. Both ECw and water ecological deficit per capital in Anyang decreased. Anyang has been in a state of water ecological deficit since 2000. The results imply that Anyang has been importing a large amount of water from other areas for its consumption since 2000. This study is expected to contribute to agricultural water management by providing suitable information to policy-makers. Furthermore, the results of this study indicate that it is urgent to make strict water resource management and water pollution prevention measures to improve the water use efficiency in Anyang and to ease the pressure on water scarcity.