Groundwater anomaly variation and its response to environment change in an inland river basin, China

Abstract

Inland river basins have plunged into water shortage with growing social development, as an important component of water resources, groundwater provides a large water supply for inland river basins. However, current understanding of groundwater dynamics and corresponding response to environment remains deficient owing to insufficient data, which needs to be further explored. To address this, we assessed groundwater storage anomaly (GWSA) through GRACE-based records over a typical inland river basin, Shiyang river basin, and analysis relevant response characteristics to environment. Annual GWSA peaked in 2004 and followed by sharply decline until 2010. Although a minor rebound occurred afterward, but overall trend of GWSA remained downward. Spatially, approximately 85 % of basin experienced a significant decline over −0.65 mm/year. In intra-annual scale, monthly GWSA show a double-peaked pattern in mountainous area while a single-peaked pattern in rest area. From 2002 to 2020, precipitation, temperature, evapotranspiration, vegetation and soil moisture show increasing trends. The largest landuse area change are cropland and unused land, cropland area was mainly converted from unused land and low-coverage grassland. Meanwhile, water and city land have increased significantly, by 21.41 % and 50.59 %, respectively, with the major transformation from unused land and cropland in oasis and desert area. Wavelet analysis reveals GWSA responds slower to temperature (0.97–1.86 months) and evapotranspiration (0.60–1.96 months) but faster to soil moisture (0.23–1.19 months). The SEM analysis indicates that GWSA was positively influenced by both precipitation and soil moisture in oasis and desert areas (>0.65), while those in mountainous area was mainly positively influenced by precipitation (0.38). Evapotranspiration and temperature contribute negative impacts on GWSA, with the lower the elevation, the greater the negative impact. These findings deepen understanding of regional groundwater dynamics and provide valuable insights for government groundwater resource management and sustainable development strategies for inland river basin.