Jimmy Jiao obtained his BEng and MEng in Hydrogeology from China University of Geosciences (Wuhan), China, respectively, and PhD in Civil Engineering from the University of Birmingham, UK. He worked as Editor (2008-2015) of Hydrogeology Journal and Associated Editor (2002-2008) for Ground Water. He has been selected as the 2022 Ineson Lecturer on coastal hydrogeology by IAH-Great Britain and Hydrogeology Group of the Geological Society London. He was the 2023 recipient of O.E. Meinzer Award, Hydrogeology Division, Geological Society of America and the 2011 recipient of the John Hem Excellence in Science and Engineering Award, National Ground Water Association. Dr Jiao was elected Fellow of the Geological Society of London, the Geological Society of America, and the American Society of Civil Engineers. He has published over 220 SCI journal papers and a book on Coastal Hydrogeology (Cambridge University Press. Co-authored with Vincent Post). He is a member of Expert Advisory Committee of Water Resources Assessment, China Geological Survey (2020- present). He was also an expert panel member for Public Utilities Board, Singapore, for Groundwater Resource Assessment in Singapore (2013 – 2019). Since 2021, he has been a member of Physical Sciences Panel (Joint Research Schemes) of the Research Grants Council, Hong Kong Government.

Study on Potential Application of Managed Aquifer Recharge

Professor Jimmy Jiao, Department of Earth Sciences at the University of Hong Kong

Abstract:

Managed Aquifer Recharge (MAR) is the intentional recharge of water into aquifers for subsequent recovery or environmental benefits. It is commonly used to manage and safeguard groundwater resources, protect against seawater intrusion, and sustain environmental flows and ecosystems. MAR utilizes various water sources, including rainwater, reclaimed water, and rural runoff. MAR offers advantages over other storage methods, such as lower costs, greater capacity, and less land surface area required. Aquifers also provide natural treatment functions and biodegradation of trace organics.

This presentation discusses three MAR case studies. The first study evaluates the MAR potential in the Baoding Plain in China, considering recharge wells, infiltration basins, and in-channel recharge scenarios. Infiltration basins lose ~80% of the source water to evaporation. In terms of source water capture, in-channel recharge and recharge wells perform similarly, but compensating for the groundwater deficit caused by pumping between 2000 and 2016 would require several decades.

The second case study focuses on the marble aquifer with karst features in Yuen Long, Hong Kong. It investigates the potential of MAR to inject storm water into the aquifer in the summer and pump it out in the winter to sustain river ecosystems. Simulation models are used to explore various MAR scenarios, including infiltration ponds, single-well pumping, paired-well pumping, aquifer storage recovery (ASR), and aquifer storage and transfer recovery (ASTR). The results indicate that paired-well pumping creates smaller depression cones compared to single-well pumping, and ASTR outperforms ASR and infiltration pond options. The marble aquifer can sustain pumping rates of up to 6000 m3/day for five months per year.

The third case study explores the use of artificial islands in the Lantau Tomorrow Vision project in Hong Kong as underground reservoirs for rainwater. These islands, made of porous fill materials, function as aquifers for significant water storage. With MAR facilities like infiltration ponds and ditches hidden in the green belts, the islands act as "sponge cities," storing rainwater to enhance flood resilience during extreme storms. Initially, the infiltrated rainwater mixed with residual seawater is suitable for industrial use, gradually becoming fresh enough for drinking. This study shows that the artificial islands can serve as both development spaces and groundwater reservoirs, meeting the area's developmental needs.