Shallow groundwater dynamics and its driving forces in extremely arid areas: a case study of the lower Heihe River in northwestern China

Wang, Ping; Yu, Jingjie; Pozdniakov, S.; Grinevsky, Sergey O.; Liu, Changming

doi:10.1002/hyp.9682

Cited by 79 publications

(55 citation statements)

References 75 publications

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“…This approach has been successfully applied in the Okavango Delta in Botswana (Bauer et al, 2004), an upland grassland catchment in central Argentina (Engel et al, 2005), an oak/grassland site on the Great Hungarian Plain of eastern Hungary (Nosetto et al, 2007), the Sopron Hills of western Hungary (Gribovszki et al, 2008), the Gobi desert of northwestern China (Wang et al, 2014), and various sites in the USA (Butler et al, 2007;Lautz et al, 2008;Martinet et al, 2009). The White method tends to over-estimate ET g (Loheide et al, 2005;Martinet et al, 2009).…”

Section: Sub-daily Fluctuation In Groundwater Depthmentioning

confidence: 99%

Groundwater-dependent ecosystems: recent insights from satellite and field-based studies

Eamus

Zolfaghar

Villalobos‐Vega

et al. 2015

Hydrol. Earth Syst. Sci.

128

112

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Abstract. Groundwater-dependent ecosystems (GDEs) are at risk globally due to unsustainable levels of groundwater extraction, especially in arid and semi-arid regions. In this review, we examine recent developments in the ecohydrology of GDEs with a focus on three knowledge gaps: (1) how do we locate GDEs, (2) how much water is transpired from shallow aquifers by GDEs and (3) what are the responses of GDEs to excessive groundwater extraction? The answers to these questions will determine water allocations that are required to sustain functioning of GDEs and to guide regulations on groundwater extraction to avoid negative impacts on GDEs.We discuss three methods for identifying GDEs: (1) techniques relying on remotely sensed information; (2) fluctuations in depth-to-groundwater that are associated with diurnal variations in transpiration; and (3) stable isotope analysis of water sources in the transpiration stream.We then discuss several methods for estimating rates of GW use, including direct measurement using sapflux or eddy covariance technologies, estimation of a climate wetness index within a Budyko framework, spatial distribution of evapotranspiration (ET) using remote sensing, groundwater modelling and stable isotopes. Remote sensing methods often rely on direct measurements to calibrate the relationship between vegetation indices and ET. ET from GDEs is also determined using hydrologic models of varying complexity, from the White method to fully coupled, variable saturation models. Combinations of methods are typically employed to obtain clearer insight into the components of groundwater discharge in GDEs, such as the proportional importance of transpiration versus evaporation (e.g. using stable isotopes) or from groundwater versus rainwater sources.Groundwater extraction can have severe consequences for the structure and function of GDEs. In the most extreme cases, phreatophytes experience crown dieback and death following groundwater drawdown. We provide a brief review of two case studies of the impacts of GW extraction and then provide an ecosystem-scale, multiple trait, integrated metric of the impact of differences in groundwater depth on the structure and function of eucalypt forests growing along a natural gradient in depth-to-groundwater. We conclude with a discussion of a depth-to-groundwater threshold in this mesic GDE. Beyond this threshold, significant changes occur in ecosystem structure and function.

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Section: Sub-daily Fluctuation In Groundwater Depthmentioning

confidence: 99%

Groundwater-dependent ecosystems: recent insights from satellite and field-based studies

Eamus

Zolfaghar

Villalobos‐Vega

et al. 2015

Hydrol. Earth Syst. Sci.

128

112

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“…One was interested in the hydrological controls of the desert riparian forests, mainly exploring the relationships between groundwater and vegetations, from leaf scale to communities level (Chen et al, 2003(Chen et al, , 2006Hao et al, 2008Hao et al, , 2010Zhang et al, 2011;Zhu et al, 2012;Wang et al, 2014;Li et al, 2008Li et al, , 2013. The other attempted to estimate ecological water requirements of the desert riparian forests for the water resource management (Wang et al, 2002(Wang et al, , 2005Liu, 2004;Ye et al, 2007;Chen et al, 2007;Chen et al, 2008a).…”

mentioning

confidence: 99%

Evapotranspiration and its main controlling mechanism over the desert riparian forests in the lower Tarim River Basin

Yuan

Luo

Shao

et al. 2015

Sci. China Earth Sci.

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Evapotranspiration (ET) and its controlling mechanism over the desert riparian forests in arid regions are the important scientific basis for the water resources managements of the lower reaches of the inland rivers of China. Nearly three years of continuous measurements of surface ET, soil water content at different depths and groundwater table over a typical Tamarix spp. stand and a typical Populus euphratica stand were conducted in the lower reach of the Tarim River. The ET seasonal trends in the growing season were controlled by plant phenology, and ET in non-growing season was weak. The diurnal variations of ET resulting from the comprehensive effects of all atmospheric factors were significantly related with reference ET. The spatial pattern of ET was determined by vegetation LAI, more vegetation coverage, more ET amount. Groundwater is the water source of surface ET, and the soil water in shallow layers hardly took part in the water exchange in the groundwatersoil-plant-air system. The temporal processes of ET over the Tamarix stand and the Populus stand were similar, but the water consumption of the well-grown Populus euphratica was higher than that of the well-grown Tamarix spp. Further analysis indicates that plant transpiration accounts for most of the surface ET, with soil evaporation weak and negligible; groundwater table is a crucial factor influencing ET over the desert riparian forests, groundwater influences the processes and amounts of ET by controlling the growth and spatial distribution of desert riparian forests; quantifying the water stress of desert riparian forests using groundwater table is more appropriate, rather than soil water content. Based on the understanding of ET and water movements in the groundwater-soil-plant-air system, a generalized framework expressing the water cycling and its key controlling mechanism in the lower reaches of the inland rivers of China is described, and a simple model to estimate water requirements of the desert riparian forests is presented. lower reaches of the Tarim River, water cycling, evapotranspiration, desert riparian forests, Tamarix spp., Populus euphratica Citation:Yuan G F, Luo Y, Shao M A, et al. 2015. Evapotranspiration and its main controlling mechanism over the desert riparian forests in the lower Tarim River

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“…A possible reason for this is that the volume of runoff in the west river is less than in the east river (see Figure ) during 2001 and 2012. This is also proven by historical records in which, during 1988 and 2011, the runoff from the east river and the west river accounted for approximately 71% and 28% of the total runoff, respectively (Wang et al, ). Consequently, we suggest that runoff in the west river should be increased to some degree.…”

Section: Results and Analysismentioning

confidence: 72%

Vegetation responses to an ecological water conveyance project in the lower reaches of the Heihe River basin

Zhang

Chen

et al. 2017

Ecohydrology

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The lower reaches of the Heihe River basin (HHLR), which is located in arid and semiarid areas of Northwest China, has experienced severe environmental deterioration in the past several decades. The ecological water conveyance project was initiated by the Chinese Government in 2000 to address this degraded ecosystem. In this paper, runoff, vegetation changes, and the relationship between runoff and vegetation in different regions were explored after the project, normalized difference vegetation index (NDVI), as a proxy of vegetation cover. For the entire lower reaches, NDVI and runoff exhibit an increasing trend after the project. In spatial, 44% of the vegetation‐covered area is significantly increased; whereas, 37% also exhibits an insignificant increasing trend. Moreover, 15% of the vegetation‐covered area shows an insignificant decreasing trend, and 5% exhibits a significant decrease. Overall, vegetation in HHLR improved after the ecological water conveyance project. The maximum time lag for NDVI along the east river and runoff from the east river, NDVI in the Ejina Oasis and runoff from the east river and the east canal, and NDVI along the west river and runoff from the west river was 4, 4, 3, and 6 years, respectively. However, runoff from last year had a significant influence on the current year's NDVI for the east river and the east canal. Meanwhile, autumn runoff shows a significant influence on the next year's NDVI, and spring runoff is important to the current year's NDVI. So we concluded that it is reasonable to convey more water into HHLR in autumn and spring.

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Shallow groundwater dynamics and its driving forces in extremely arid areas: a case study of the lower Heihe River in northwestern China

Cited by 79 publications

References 75 publications

Groundwater-dependent ecosystems: recent insights from satellite and field-based studies

Groundwater-dependent ecosystems: recent insights from satellite and field-based studies

Evapotranspiration and its main controlling mechanism over the desert riparian forests in the lower Tarim River Basin

Vegetation responses to an ecological water conveyance project in the lower reaches of the Heihe River basin

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