San Carlos Reservoir Nears Empty Amid Drought, Widespread Fish Deaths
The San Carlos Reservoir in Arizona reached critically low water levels in May 2026, dropping to less than one percent of its capacity. This significant reduction, attributed to drought conditions and mandatory water releases, has led to widespread fish deaths due to hypoxia. Authorities indefinitely closed the reservoir on June 5, 2026, citing potential health risks from decomposing fish. Satellite imagery from NASA captured the dramatic decline from June 2023 to May 2026.
The San Carlos Reservoir in Arizona reached critically low water levels in May 2026, with satellite imagery revealing the reservoir as nearly empty. Data from the Operational Land Imager (OLI) on the Landsat 9 and 8 satellites showed that on May 22, 2026, the reservoir stored 389 acre-feet of water, representing less than one percent of its full capacity. This starkly contrasts with June 2023, when the reservoir was approximately 60 percent full. The Gila River’s natural channel, flanked by green vegetation, became visible where the reservoir bottom once lay.
The severe decline in water levels is attributed to a combination of multi-year drought conditions and mandatory water releases for downstream agricultural use. In 2026, the Gila River watershed experienced lackluster snowfall, with the mountain snowpack at only two percent of the 1991-2020 March median. This limited snowpack resulted in April streamflow being 39 percent of normal, further impacting the reservoir's capacity.
The drastically low water levels led to significant environmental consequences. Officials closed the reservoir indefinitely on June 5, 2026, following widespread fish deaths. Low oxygen levels, known as hypoxia, killed virtually all fish species, including largemouth bass, black crappie, bluegill, channel catfish, flathead catfish, brown trout, and rainbow trout. The San Carlos Recreation and Wildlife Department warned of potential health risks from the decomposing fish to individuals attempting to boat or fish in the area.
This is not the first instance of extreme low water at the San Carlos Reservoir, which has reportedly run out of water at least 20 times since its initial filling in 1930. Major fish kills also occurred in 1976 and 2018. Following a similar event in 1976 where over five million fish perished, the Gila Herald reported that the lake's ecosystem required five years to recover. The region continues to face a multi-year dry period, contributing to severe drought conditions in the Gila River's headwaters in New Mexico.
According to NASA Breaking News, humorist Will Rogers famously commented on the extent of the dry reservoir bottom during its dedication, quipping to President Calvin Coolidge, "If that was my lake, I’d mow it."
