There’s another water crisis happening in the Colorado River Basin — and this one’s invisible

illuminem summarises for you the essential news of the day, reviewed by our editorial team. Read the full piece on CNN or enjoy below:

🗞️ Driving the news: Groundwater reserves beneath the Colorado River Basin are declining rapidly, adding a hidden dimension to the Southwest’s escalating water crisis
• A new Virginia Tech study, published in Water Resources Research, analysed satellite observations and hydrological data from 2004 to 2023
• It found that groundwater depletion accelerated after 2019, with the traditionally more resilient Upper Basin experiencing particularly severe losses during the 2020–2022 drought

🔭 The context: The Colorado River supplies water to nearly 40 million people, while Lake Mead and Lake Powell have become highly visible symbols of regional drought
• Groundwater provides a crucial backup when rivers and reservoirs run low, but aquifers recharge slowly and are vulnerable to sustained extraction
• Historically, groundwater losses were greater in the Lower Basin, covering Arizona, California and Nevada
• Researchers link the changing pattern to prolonged drought, higher temperatures, reduced snowmelt and human water demand. The study does not isolate the precise contribution of each factor

🌍 Why it matters for the planet: Groundwater depletion threatens drinking-water supplies, agriculture and ecosystems that depend on underground reserves and groundwater-fed rivers
• As climate change intensifies heat and drought risks, managing surface water alone will not protect the basin’s long-term water security

⏭️ What’s next: With Colorado River states facing water-use cuts, policymakers will need to account for groundwater alongside reservoirs and river flows
• Researchers stress the need for integrated management that addresses both climate pressures and human extraction

💬 One quote: “Focusing only on reservoirs could therefore overlook an important part of the region’s overall water challenges,” said study author Esther Oyedele.

📈 One stat: 17.5 cubic kilometres — estimated groundwater loss in the Upper Colorado River Basin during the 2020–2022 drought, nearly double the Lower Basin’s 9.4 cubic kilometres.

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