Seminar

Tung Chung River and Lam Tsuen River are both Ecologically Important Streams in Hong Kong. The climatic forcing and water divisions to reservoirs during 2000-2012 resulted in dramatic declines of groundwater storage, along with statistically significant increasing trend of silica concentration in river water of both Tung Chung and Lam Tsuen Watersheds. Although more humid climate during 2012-2020 ensures the recovery of groundwater storage, the variation of groundwater storage is decoupled from aridity index and much vulnerable to water diversion. Very strong negative relationship between the silica concentrations in river water and groundwater storage in both watersheds indicates that Si is the ideal proxy of the groundwater storage dynamics influenced by water diversion in the baseflow dominant volcanic headwater streams. Groundwater storage is more sensitive to water diversion and climatic forcings under lower relief settings, likely as a result of the release of older groundwater with enriched silicate.

Additional information: Mr. SU Jintao, sudosu@connect.hku.hk