In the Volcanoes Region, underground water systems are complex. Rainwater seeps into volcanic rocks, sinkholes, and caves, sometimes reappearing as springs far away. For many years, little was known about how this water moves, is replenished, or connects with rivers and lakes, limiting planning and disaster preparedness. 

The Mugogo lowland illustrates this complexity. It receives water from the Kinoni River and nearby catchments. Some water from the volcano disappears into underground caves before reappearing downstream.

 To better understand this intricate system, the Rwanda Water Resources Board, with support from the International Atomic Energy Agency, is employing isotope hydrology. Isotopes act as natural “fingerprints” in water molecules, revealing where water originates, how long it has been underground, and how surface and groundwater are interconnected.

 In complex areas like the Mugogo lowland, this approach provides essential insights for sustainable water management. 

The benefits of this activity extend beyond science. Understanding groundwater dynamics helps protect communities from floods and water shortages, supports farmers with reliable irrigation, safeguards ecosystems and tourism in the Volcanoes National Park, and informs national policies for climate resilience and sustainable water use.