What makes the Indo-Gangetic Basin one of the most important aquifers in the world? How do stable isotopes, CFCs, and even traces of pharmaceuticals help us understand where groundwater comes from and how old it is? Can satellites like GRACE and InSAR give us new insights into groundwater depletion and recharge in South Asia?

Alan M. MacDonald, Head of Groundwater at the British Geological Survey, joins host Veena Srinivasan on Season 2, Episode 6 of the Water Data Podcast.

Alan is a hydrogeologist with over 30 years of research experience in Africa and South Asia, and has published widely on groundwater, climate change, and aquifer systems

In this episode, Alan and Veena dive deep into the Indo-Gangetic Basin, exploring how its young sediments and complex geology shape groundwater availability, why salinity and depletion can exist side by side, and how historical canal records still influence water levels today.

Alan explains how tracer studies and isotope hydrology reveal the origins of groundwater, and how modern tools like satellites are transforming our understanding of recharge, depletion, and salinity.

The Water Data Podcast is a talk show on the science, systems, and stories of water hosted by Veena Srinivasan.

For all references and further readings related to the episode, visit https://welllabs.org/wdp-alanmacdonald/

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Recording by Nabina Chakraborty and Nanditha Gogate. Video editing by Vraj Acharya. Graphics and artwork by Aparna Nambiar. Audio mixing and mastering by Vijay Doiphode. Podcast production and management by Nabina Chakraborty and Pavan Srinath.