Abstract
Desert oases are important parts of maintaining ecohydrology. However, irrigation water diverted from the Yellow River carries a large amount of salt into the desert oases in the Hetao plain. It is of the utmost importance to determine the characteristics of water and salt transport. Research was carried out in the Hetao plain of Inner Mongolia. Three methods, i.e., water-table fluctuation (WTF), soil hydrodynamics, and solute dynamics, were combined to build a water and salt balance model to reveal the relationship of water and salt transport in sand dune–wasteland–lake systems. Results showed that groundwater level had a typical seasonal-fluctuation pattern, and the groundwater transport direction in the sand dune–wasteland–lake system changed during different periods. During the crop-growth period (5 May–27 October), the average evapotranspiration values of the sand dune, wasteland–sand dune junction, and wasteland were 31–42% of the reference evapotranspiration. The water consumption of sand dune was 1.95 times that of the wasteland–sand dune junction, and 1.88 times that of wasteland. Water loss of the lake was 761.25–869.05 mm (5 May–27 October). The lake is facing the risk of drying up. The vertical salt transport of groundwater at the sand-dune site was 1.13 times that at the wasteland–sand dune junction site, and 1.82 times that at the wasteland site. Of the groundwater salt of the sand dune, 54% was accumulated in the groundwater of the wasteland–sand dune junction. Of the groundwater salt of the wasteland–sand dune junction, 53% was accumulated in wasteland groundwater, and the remaining 47% was accumulated in the lake. Salt storage of the 1 m soil layer of the sand dune was 85% that of the wasteland–sand dune junction, and 82% that of the wasteland. Research results provide a theoretical basis for the ecohydrology of the Hetao plain.
Highlights
Northwestern China is an arid region with little annual rainfall and a large amount of yearly evaporation
Hou et al [7] reported that quantification of groundwater recharge from precipitation in huge sand dunes is an issue in regional water balance in the Badain Jaran desert (BJD)
Results of this study provide a theoretical basis for water-resource utilization and water salt transport in the Hetao Irrigation District (HID)
Summary
Northwestern China is an arid region with little annual rainfall and a large amount of yearly evaporation. In order to reveal whether rainfall recharged sand-dune groundwater, many researchers quantitatively estimated the infiltration recharge using physical models and water-balance methods [8]. Gong et al [6] showed that groundwater-fed lakes are essential for the ecology in arid and semiarid regions. Hou et al [7] reported that quantification of groundwater recharge from precipitation in huge sand dunes is an issue in regional water balance in the Badain Jaran desert (BJD). Chen et al [11,12] found that the shallow groundwater of sand dunes was the recharge source of lakes. Wen et al [13] indicated that precipitation infiltration was the main water source for sand dunes. Wang et al [14] found that lake level was decreased by 70 cm during the growing period in the
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