Quantifying the impacts of land use/land cover change on groundwater depletion in Northwestern China – A case study of the Dunhuang oasis

Abstract:Understanding the processes of land use and land cover changes (LUCC) and the associated driving forces is important for achieving sustainable development. This paper presents the LUCC in Portugal at the regional level (NUTS II) from 1995 to 2010 and discusses the main driving forces and implications associated with these LUCC. The main objectives of this work are: (a) to quantify the land use and land cover (LUC) types (level I of LUC cartography) by NUT II in Portugal for the years 1995, 2007 and 2010; (b) to assess the spatio-temporal LUCC; and (c) to identify and discuss the main driving forces of LUCC and corresponding implications based on correlations and Principal Components Analysis. The results revealed large regional and temporal LUCC and further highlighted the different and sometimes opposite time trends between neighboring regions. By associating driving forces to LUCC, different influences at the regional level were observed, namely LUCC into agriculture land derived from the construction of dams (Alentejo region), or the conversion of coniferous forest into eucalypt forest (Centre region) associated with increased gross value added (GVA) and employment in industry and forestry. Temporal differentiation was also observed, particularly in the settlements that expanded between 1995 and 2007 due to the construction of large infrastructures (e.g., highways, industrial complexes, or buildings), which is reflected on employment in industry and construction and respective GVA. However, certain LUCC have implications, particularly in energy consumption, for which different behavior between regions can be highlighted in this analysis, but also on land-use sustainability.

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“…This LUCC dynamics are also referred to in other studies carried out in other territories (e.g., [17,20,63,79]). …”

Section: Discussionmentioning

confidence: 96%

Understanding Driving Forces and Implications Associated with the Land Use and Land Cover Changes in Portugal

et al. 2017

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“…Heilonggang is a drought-and flood-prone coastal alluvial plain. Since the 1970s, groundwater levels have declined as a result of climate change, human activities [1] and increased demands for water [2], resulting in the formation of a perennial shallow groundwater depression cone over a wide area. This cone is still expanding and has triggered problems such as land subsidence [3].…”

Section: Introductionmentioning

confidence: 99%

Impact of Groundwater Level on Nitrate Nitrogen Accumulation in the Vadose Zone Beneath a Cotton Field

Jiao

Maimaitiyiming

Salahou

et al. 2017

Water

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Abstract:In this study, the impacts of groundwater level on nitrate nitrogen accumulation in the vadose zone of a cotton field were investigated. Experiments were conducted in a cotton field at the CAS Ecological Agricultural Experiment Station in Nanpi from 2008 to 2010. A vertical observation well was drilled, and time-domain reflectometry probes and soil solution extractors were installed every 50 cm in the walls of the well to a depth of 5 m. The soil water content was monitored, and soil solution samples were obtained and analyzed every six days throughout the growing seasons during the three studied years. Additionally, a water consumption experiment was conducted, and the topsoil water content and leaf area index were measured in the cotton field. The resulting data were used to estimate parameters for use in a soil hydraulic and nitrate nitrogen movement model, and cotton evapotranspiration was calculated using the Penman-Monteith method. Groundwater level increases and decreases of ±4 m were simulated during a ten-year period using HYDRUS-1D. The results showed significant nitrate nitrogen accumulation in the vadose zone when the groundwater level remained unchanged or decreased, with increased accumulation as the groundwater depth increased. Additionally, increased precipitation and a deeper groundwater level resulted in greater nitrate nitrogen leaching in the cotton root zone. Therefore, irrigation and fertilization strategies should be adjusted based on precipitation conditions and groundwater depth.

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“…After all, during thousands of years of oasis evolution, the threats of 20 desertification have consistently occurred and the existence and disappearance of oases are largely related to the abundance or shortage of water resources [Lu et al, 2003;Jia et al, 2004;Zhang et al, 2014]. Thus, unsuitable oasis expansion alongside the inappropriate utilization of water resources will finally result in desertification.…”

Section: Enriching Oasis Science and Enhancing Desertification Researmentioning

confidence: 99%

“…15 The understanding of the oasis evolution process could provide corresponding theories for oasis exploitation [Xie et al, 2014;Xie et al, 2015]. Currently, research related to oasis evolution has mainly focused on four aspects: analysis ofland use patterns and their driving factors in oasis regions [Guo et al, 2008;Bai et al, 2014;Wang et al,2014;Song and Zhang, 2015], discussion ofthe relationship between oasis evolutionand water resources [Siebert et al, 20 2007;Liu et al, 2010], assessment of the ecological effects of oasis evolution [Su et al, 2007;Zhang et al, 2014], and determination on the suitable oasis scale [Ling et al, 2013; 2016]. These studies mainly concentrated on agricultural oases since these represent the typical landscape surrounding oases.…”

Section: The Importance Of Oasification Researchmentioning

confidence: 99%

Should oasification be ignored when examining desertification in Northwest China?

GUI

Xue

Liu

et al. 2017

Preprint

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Abstract. There has been substantial expansion of oases in the Northwest of China in recent decades; however, research has largely focused on desertification rather than oasification and its associated mechanisms. Based on the description of desertification in arid regions and other regions, and analysis of oasification in arid or hyper-arid areas, we firstly elucidate the theoretical relationship between oasification and desertification. We then examine the current 5 understanding in oasification research, and propose that this will enhance our understanding of desertification through the integration of studies of oasification. Finally, we suggest three potential topics for future oasification research. We also propose a simple conceptual model for the identification of an appropriate oasis size under different land uses, including the crucial assessment of associated uncertainties. Based on the analysis of oasification research from an 10 epistemological and methodological perspective, we suggest that oasification should have equal research status to desertification in arid regions.

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Quantifying the impacts of land use/land cover change on groundwater depletion in Northwestern China – A case study of the Dunhuang oasis

Cited by 68 publications

References 14 publications

Understanding Driving Forces and Implications Associated with the Land Use and Land Cover Changes in Portugal

Understanding Driving Forces and Implications Associated with the Land Use and Land Cover Changes in Portugal

Impact of Groundwater Level on Nitrate Nitrogen Accumulation in the Vadose Zone Beneath a Cotton Field

Should oasification be ignored when examining desertification in Northwest China?

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