Indigenous communities across the Amazon are losing access to clean water as illegal mining, deforestation cattle ranching and other human activities transform rivers, streams and lakes a major investigation has found.
The investigation analysed 722 micro watersheds feeding four major river basins the Beni in Bolivia, the Caquetá in Colombia, the Madre de Dios in Peru and the Caroní in Venezuela over a 25 year period from 2000 to 2024. These areas are home to at least 74 Indigenous groups across 202 territories.
The findings show that the four river basins lost nearly 33,000 hectares of natural water bodies during the period. More than half of the micro watersheds studied, 393 out of 722, recorded a decline in natural water resources.
Researchers also identified more than 17,000 hectares of newly formed or transformed water bodies, largely associated with mining activities. Although these artificial ponds make some areas appear to have more water, much of it is stagnant or polluted and unsuitable for drinking.
In Peru’s Madre de Dios region, Indigenous Harakmbut communities say illegal gold mining has contaminated the Inambari River, once a vital source of drinking water, fishing and other daily activities. Residents now have to purchase drinking water, with some families spending around $21 a week on water tanks.
Similar problems are affecting Indigenous communities in Bolivia, where mining has polluted rivers and created artificial ponds. In the Beni River basin, nearly 14,000 hectares of natural water bodies disappeared, while around 3,000 hectares of mining pits emerged. Residents of the Leco community of Tomachi report that the Kaka River, once known for its clear water and abundant fish, has become polluted by mining operations.
In Venezuela, mining has contributed to the disappearance of natural water bodies and the contamination of rivers with sediment and heavy metals, including mercury. Members of the Pemón community in Apoipó recalled a lagoon that once supported fishing but has now dried up completely.
The situation is different in Colombia’s Caquetá region, where deforestation and cattle ranching have placed severe pressure on natural water sources. The investigation recorded the largest loss of natural water in this basin, amounting to 21,532 hectares. In the Indigenous reserve of Jácome, a lagoon that covered more than 10 hectares in 1998 had shrunk to less than one hectare by 2024.
Residents attribute the decline to a combination of expanding cattle ranches, forest clearance, changes in rainfall patterns and local land use practices. Community members say streams that once remained available for much of the year now dry up after only a few days without rain.
Deforestation also threatens the Amazon’s natural water cycle. Forests absorb rainfall, store moisture in the soil and release water vapour into the atmosphere through evapotranspiration. This moisture helps generate rainfall across the wider region. When forests are cleared, the natural system that stores and redistributes water can be disrupted potentially reducing rainfall and worsening water shortages.
Scientists involved in the investigation stressed that the appearance of new water bodies does not necessarily indicate improved water availability. Satellite imagery can measure the surface area of water but cannot establish whether it is clean, drinkable or available in sufficient quantities for communities.
The investigation also found that mining related artificial water bodies frequently overlap with Indigenous territories. At least 64 micro watersheds or river sections that gained mining ponds are located within these territories, leaving communities exposed to pollution and the loss of traditional water sources.
Despite the challenges, Indigenous communities are working to protect what remains. In Bolivia, the Leco community is defending its last two streams from mining expansion. In Colombia the Coreguaje community has established a nursery containing more than 40,000 native tree seedlings to help restore forest cover along waterways.
The findings highlight a growing environmental and social challenge across the Amazon: a region that appears abundant in water is increasingly leaving its Indigenous residents without reliable access to safe drinking water. Protecting forests, limiting destructive mining and restoring natural water systems will be essential to safeguarding the region’s rivers and the communities that depend on them.