Ancient Rock Structures Revitalize Biodiversity on US-Mexico Border
In Cananea, Sonora, rancher Eduardo Ríos Colores and his team have constructed over 100 'trincheras,' or loose-rock check-dams, since 2021 to manage water flow and support biodiversity. These structures, which have been used historically by Indigenous cultures in the region, aim to slow water flow, raise water tables, reduce erosion, and rebuild soil for vegetation recovery.
Research has shown that these rock-detention structures (RDS) are effective. A study in the Chiricahua Mountains indicated that watersheds with these structures experienced 28% higher summer monsoon flow volumes compared to unrestored areas, with the majority of dams remaining functional over decades.
Similar benefits have been observed in other arid regions. A 2026 study in the Mongolian Journal of Biological Sciences reported increased vegetation cover and enhanced species richness within two years of RDS installation. These findings are consistent with a 2021 analysis in northern Sonora, which confirmed multiple co-benefits including erosion control and increased climate resilience.
Historically, RDS have been utilized for over a millennium in the Madrean Sky Islands region by Indigenous peoples to manage water and support agriculture. A 2020 U.S. Geological Survey review documented RDS installations across approximately 800 km² of private lands on both sides of the U.S.-Mexico border, noting long-term vegetation gains and improved groundwater retention.