A recent study has provided groundbreaking insights into the movement of groundwater, revealing that underground water can travel vast distances and remain hidden for much longer periods than previously understood. Researchers from Princeton University and the University of Arizona have conducted a high-resolution simulation that traces the journey of rainwater or snowmelt as it seeps into the ground and eventually resurfaces in freshwater streams. This study reveals that water can travel underground for up to 100 miles and remain hidden for decades or even up to 100,000 years.
The simulation covered an expansive area that includes the continental United States, parts of Canada, and Mexico, tracking groundwater flow across more than 3 million square miles. The researchers found that more than half of the water flowing in rivers and streams comes from deep aquifers, which were once thought to be isolated from surface water systems. This connection between surface water and deep groundwater is crucial for understanding how groundwater systems function and for managing this vital resource.
The study has significant implications for the management of groundwater resources, particularly in light of growing concerns over pollution and climate change. As groundwater supplies a critical portion of drinking water for millions of people, the new findings could impact how pollution, such as nitrate and PFAS contamination, is tracked and managed. Because groundwater moves slowly and can travel long distances before discharging into streams, pollutants can remain underground for extended periods, making them more challenging to address. Additionally, understanding the depths at which groundwater contributes to streamflow will help improve strategies for managing water quality, conservation, and the overall sustainability of these essential resources.
This new research highlights the importance of considering groundwater as part of broader water management strategies and provides a more comprehensive understanding of how groundwater and surface water systems interact. With the continuous depletion of groundwater resources in many areas, these insights can help guide efforts to protect and preserve this essential resource for future generations.
Read the full report here: https://www.nature.com/articles/s44221-024-00366-8
