Defining and Classifying the Formation, Characterization, and
Significance of Karst Hyporheic Zones in a Karst Peak-Forest Plain in
China
Abstract
Groundwater (GW)-surface water (SW) interactions in karst areas may have
a strong impact on the quantity and quality of the groundwater system.
Although knowledge of karst hydrology has improved in recent decades,
the interaction patterns of GW-SW, and understanding of the hyporheic
zone (HZ) on improving or deteriorating groundwater remains very
limited. Here, we document HZ in a karst basin through study of
hydrological, hydrochemical, and biological processes. The depths of
some sinkholes or karst windows in the karst plain are more than 100 m,
which are dozens of meters lower than the river elevations. The HZ is
not limited to the riverbed, but extends into aquifer along the karst
conduits. And their interaction patterns are not limited to the mixing
GW and SW, but also include mixing of groundwater with other water
bodies. Due to the existence of karst conduits, the types of HZ and the
dynamic process of hyporheic flow are unique within karst aquifers. We
defined these generally in karst groundwater systems dominated by
conduits as karst cave hyporheic zones (KCHZ), with the meaning of the
place or area where conduit flow interacts with other types of water
bodies. The KCHZ was further classified into four types. Research on the
five springs in the study area showed the formation of KCHZ is related
to the karst development and the hydrogeochemical gradient of water
environment. Once the quality of one type of water deteriorates, or the
amount of water decreases, the function of hyporheic zone will
degenerate.