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Applying indicator-based geostatistical approaches to determine potential zones of groundwater recharge based on borehole data

Jang, Cheng-Shin, Chen, Shih-Kai, Kuo, Yi-Ming
Catena 2013 v.101 pp. 178-187
aquifers, clay, geostatistics, gravel, groundwater recharge, kriging, planning, ponds, sand, silt, soil permeability, uncertainty, water management, wetlands, Taiwan
Evaluating a potential zone of groundwater recharge is considerably critical for planning a scheme of quality protection and quantity management of groundwater. This study determined potential zones of groundwater recharge using indicator kriging (IK) based on borehole data in the Pingtung Plain, southern Taiwan. Data on subsoil textures were first classified into four categories — gravel (very rapid subsoil infiltration), coarse sand to medium sand (rapid subsoil infiltration), fine sand to very fine sand (slow subsoil infiltration), and silt, mud, and clay (very slow subsoil infiltration). IK was used to characterize the classifications of subsoil infiltration by selecting a maximum estimation probability. Then, contents of fast soil permeability in unsaturated aquifers (gravel to medium sand), which represent the capacity of unsaturated aquifer percolation, were estimated spatially and probabilistically using IK. Finally, combinations under different conditions of subsoil infiltration and unsaturated aquifer percolation were recommended to delineate potential zones of groundwater recharge. Owing to limited observed data, estimated probabilities of subsoil infiltration and unsaturated aquifer percolation obtained from IK can explore the uncertainty of estimated parameters. The analyzed results reveal that IK has good functionality for determining potential zones of groundwater recharge. The northeastern and southeastern regions are main groundwater recharge zones, approximately 19.6% of total area. Artificial ponds or wetlands can be established in the determined zones to enhance groundwater recharge.