Widespread potential for streamflow leakage across Brazil

Author(s)

Uchoa, Jose Gescilam S. M. ; Oliveira, Paulo Tarso S. ; Ballarin, Andre S. ; Neto, Antonio A. Meira ; Gastmans, Didier ; Jasechko, Scott ; Fan, Ying ; Wendland, Edson C.

• Document type: Journal article
• Source: NATURE COMMUNICATIONS; v. 15, n. 1, p. 11-pg., 2024-11-25.

Abstract

River-aquifer interactions play a crucial role in water availability, influencing environmental flows and impacting climate dynamics. Where groundwater tables lie below river water levels, stream water can infiltrate into the underlying aquifer, reducing streamflow. However, the prevalence of these "losing" rivers remains poorly understood due to limited national-wide in situ observations. Here we analyze water levels in 17,972 wells across Brazil to show that most of them (55%) lie below nearby stream surfaces, implying that these nearby streams are likely seeping into the subsurface. Our results demonstrate the widespread potential for stream water losses into underlying aquifers in many regions of the country, especially in areas with extensive groundwater pumping. Our direct observations underscore the importance of conjunctively managing groundwater and surface water, and highlight the widespread risk of streamflow losses to aquifers, which could impact global water access and ecosystems that rely on rivers. Most Brazilian rivers are found to have the potential for stream water losses into underlying aquifers, especially in drier climates, thicker aquifers, and regions with extensive groundwater pumping. (AU)

• FAPESP's process: 20/08140-0 - Extreme events in a climate change context: characterization based on climate model and nonstationarity
• Grantee: André Simões Ballarin
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 22/06017-1 - Extreme events of rainfall and temperature in Brazil under a climate change context: statistical properties and future changes
• Grantee: André Simões Ballarin
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 20/15434-0 - SACRE: integrated water solutions for resilient cities
• Grantee: Ricardo César Aoki Hirata
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 23/13160-8 - IMPACT LAND USE AND LAND COVER AND CLIMATE CHANGE ON HYDROLOGICAL FLOWS BETWEEN GROUNDWATER AND SURFACE WATER IN THE GUARANI AQUIFER OUTCROP ZONE
• Grantee: José Gescilam Sousa Mota Uchôa
• Support Opportunities: Scholarships in Brazil - Doctorate