Assessing the interlinkage of green and blue water in an arid catchment in Northwest China

Ganquan Mao,Ying Meng,Yi Zheng,Feng Han,Yong Tian,Junguo Liu,Chunmiao Zheng

doi:10.1007/s10653-019-00406-3

Ganquan Mao, Ying Meng + Show 5 more

Open Access

https://doi.org/10.1007/s10653-019-00406-3

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Abstract

Water resource assessment is crucial for human well-being and ecosystem health. Assessments considering both blue and green water are of great significance, as green water plays a critical but often ignored role in the terrestrial ecosystem, especially in arid and semi-arid regions. Many approaches have been developed for green and blue water valuation; however, few approaches consider the interrelationship between green and blue water. This study proposed a new framework for green and blue water assessment by considering the interactions between green and blue water and the connections between human and natural ecosystems in an arid endorheic river basin where hydrological cycling is dramatically altered by human activities. The results show that even though green water is the dominant water resource, blue water is also critical. Most of the blue water is redirected back into the soil through physical and human-induced processes to meet the water demand of the ecosystem. The blue and green water regimes are found to be totally different in different ecosystems due to the temporal and spatial variability in water supply and consumption. We also found that humans are using an increasing proportion of water, resulting in decreasing water availability. Extensive water use by humans reduces the water availability for the natural ecosystem. Approximately 38.6% of the vegetation-covered area, which is dominated by farmland and forest, may face a moderate or high risk of increased conflict and tension over freshwater. This study provides crucial information to better understand the interactions between green and blue water and the relations between humans and nature by explicitly assessing water resources. It also provides crucial information for water management strategies that aim to balance humankind and nature.

Highlights

Renewable freshwater is a foundation for both terrestrial and aquatic ecosystems (Jackson et al 2001)
This study aims to consider the interactions between green water and blue water in the water cycle and apply an integrated surface water and groundwater model for water resource assessment with two main objectives: (1) determine how well integrated surface water and groundwater hydrological modelling efficiently and effectively simulates green and blue water dynamics while emphasizing the interlinkages between them in an arid endorheic river basin by explicitly considering irrigation, water diversion and groundwater pumping; and (2) determine how such green and blue water assessments could support basinscale water resources management to address humannature water conflicts in an arid endorheic catchment
It was found that 86% (7.40 billion m3/year) of the water from precipitation forms green water resources that are stored in soil, and only 14% (1.23 billion m3/year) of precipitation runs off when it reaches the surface

Summary

Introduction

Renewable freshwater is a foundation for both terrestrial and aquatic ecosystems (Jackson et al 2001). Water scarcity has become a worldwide problem, and its intensity has increased due to climate change and human activities, e.g. unsustainable land and water management (Liu et al 2017; Veldkamp et al 2017). This has become a major constraint to our socioeconomic development. Renewable freshwater availability assessments are crucial for better water resource management and for resilience against water scarcity under the changing environment (Rockstrom et al 2009a)

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