Seminar

Nested groundwater flow systems (NGFS) are commonplace in various hydrogeological environments. This study focuses the control mechanisms of NGFS and their mediation on hydrogeochemical and isotopic characterizations. Three questions are mainly investigated. First, saline water often emerges in the low-lying depressions of evaporitic basins. How the formation of saline water impacts the regional groundwater flow system has not been addressed in the literature. Second, the groundwater table is subject to fluctuations of multiple time scales, which may have significant impacts on the NGFS and surface runoff. The responses of the NGFS to rainfall and the impacts of the NGFS on surface runoff are rarely discussed before. Third, previous theoretical studies indicate that in recharge-controlled aquifers, the regional groundwater flow system is dominant, but local groundwater flow systems are usually less developed or even non-existent. The occurrence and role of local groundwater flow systems in real recharge-controlled systems are rarely examined. These questions are explored via field sampling, laboratory measurements, data analysis, and numerical simulations. The findings of this study will benefit the understanding of the groundwater flow systems and their mediation on hydrogeochemical and isotopic characterization.

Additional information: Mr. Xiaolang ZHANG, u3005530@connect.hku.hk