Ecohydrological characteristics and distribution of groundwater
dependent ecosystems (GDEs) in Langxi river watershed, North China
Abstract
Groundwater dependent ecosystems (GDEs) must have access to groundwater
to maintain their ecological structure and function. The rapid expansion
of humans has increased demands on groundwater for consumption, industry
and agriculture, these demands alter groundwater regimes of natural
GDEs, resulting in the degradation of ecosystem health. In order to
improve the conceptual understanding of the role of groundwater in such
ecosystems, this study examined key aspects of GDEs (hydrogeology,
hydrogeochemistry and biodiversity) in the Langxi river watershed, North
China. Results indicate that the karst in Langxi river watershed is well
developed. The water chemistry types in the watershed were mostly
HCO3-Ca type with different clustering characteristics, which indicate
different degrees of interaction between surface water and groundwater,
and that the recharge processes and flux of GDEs are different. Land use
type and humidity maps were obtained by remote sensing interpretation,
and combined with the groundwater isolines, it can be seen that in the
dry season, when the groundwater level higher than the maximum depth of
vegetation root system, and areas with high humidity, were the GDEs
distribution areas. Water quality of the Longchi and Zhangxia Group
aquifer is good and the content of Sr is high, suggesting that it can be
used as a partial strontium type natural mineral water. It was also
found that there are several types of stygofauna in the GDEs of the
Langxi river watershed, indicating that the water quality of the
sampling points has not been contaminated.