Why are Elephant Butte water levels so low?

Elephant Butte Lake is low because the Rio Grande has delivered less water than the reservoir gives up. Since 2000, the releases Reclamation makes for farms in southern New Mexico, West Texas and Mexico, plus what evaporates off the lake, have matched or outrun what flowed in, and in 2026 the spring snowmelt barely arrived at all.

Elephant Butte Reservoir's water level was 4,295.96 feet above sea level on Oct 15, 2026, 111.04 feet below full pool (4,407 feet), with 94,701 acre-feet in storage (5% of capacity). Its lowest reading of the past year, 4,275.13 feet on Jul 29, 2026, was the lowest since October 1971. The record low is 4,258.03 feet, set on Aug 6, 1954.

The chart is the lake's level at the end of every year since 1915, from Reclamation's daily reading at the dam. Full pool is 4,407 feet. The table has every year's closing level, change, low and high.

What the reservoir is for

Elephant Butte Dam was completed in 1916, with storage under way since January 1915. It is the main storage of Reclamation's Rio Grande Project, which supplies irrigation water for about 178,000 acres in the Rincon, Mesilla and El Paso valleys, about 60 percent of them in New Mexico and 40 percent in Texas. Reclamation's project history also records an annual allowance of 60,000 acre-feet for diversion to Mexico at Juarez. Caballo Reservoir, 25 miles downstream, re-regulates the releases. The lake works as a carryover bank: a big snow year in southern Colorado and northern New Mexico fills it, and the project draws it down through the dry years after.

Where the water goes

Reclamation publishes the reservoir's daily inflow, release and evaporation. Summed by water year, October through September, they show where the water went.

Over the 20 water years from 2007 through 2026, 10.43 million acre-feet flowed in, 9.37 million acre-feet was released and 1.48 million acre-feet evaporated. In the wet years, 2008, 2017, 2019 and 2023, inflow ran well ahead of releases and the lake rose. In dry ones the project released more than came in: 619,131 acre-feet out against 358,700 in during 2020, and 659,172 out against 499,478 in during 2024. Each wet year's gain was gone within a few years, and the lake has not stood above 4,354.77 feet, its reading of Feb 17, 2009, since.

The big drop came first

The lake was close to full through the mid-1980s and mid-1990s. It reached full pool in November 1986 and ended every year from 1985 through 1995 above 4,384 feet. On Sep 30, 1999 it held 1,635,640 acre-feet. Over the next five water years Reclamation released 3.21 million acre-feet and 630,000 acre-feet evaporated, while storage fell 1.54 million acre-feet, to 96,400 on Sep 30, 2004. The arithmetic implies about 2.3 million acre-feet flowed in across those five years, roughly 460,000 a year, against releases that averaged 643,000. A full lake also loses far more to the air: evaporation ran 216,000 acre-feet a year on average over water years 1991 to 2000, and 25,472 acre-feet in water year 2026.

Why the same level holds less water

Reclamation converts the surface reading into storage with an area-capacity table, and silt carried in by the Rio Grande has taken up room the reservoir once had. Caballo Dam was built in part to replace storage lost to silt at Elephant Butte. Reclamation's own daily record shows the effect: at 4,350 feet the lake held 953,041 acre-feet on Jun 3, 1919, and 643,740 acre-feet on Jun 15, 2008. That is why the history above is told in feet. A foot of surface means the same thing in 1920 and in 2026, while an acre-foot total depends on which survey's table was in use. This site measures percent of capacity against 2,010,900 acre-feet, the capacity in Reclamation's reservoir-conditions data.

Worked example: 2026

The lake's high for the year came on Apr 17, at 4,319.27 feet with 251,819 acre-feet. In a normal spring the snowmelt arrives as the irrigation season starts. In 2026 it barely did: from Apr 1 through Jul 31 Reclamation logged 18,252 acre-feet of inflow while releasing 232,324 acre-feet, most of it between Apr 28 and Jul 31. For the same four months inflow was 561,206 acre-feet in 2023, 234,468 in 2024 and 65,333 in 2025.

By Jul 29 the lake stood at 4,275.13 feet with 26,732 acre-feet, 44.14 feet below its April high. It had dropped below 4,282.2 feet, the top of the inactive pool in Reclamation's record for the dam, on Jul 15, and stayed under that line until Sep 29. Those were its first readings below it since 1972. Reclamation's glossary defines inactive storage as water normally not available for release. The season's releases ended on Jul 31.

Then the river came up. From Sep 17 to Oct 12 Reclamation counted 64,814 acre-feet of inflow with almost nothing released, and upstream the Rio Grande at Otowi Bridge peaked at 1,440 cubic feet per second on Sep 30. The lake rose from 4,275.69 feet on Sep 16 to 4,295.85 feet on Oct 14.

The Otowi Bridge gauge measures the Rio Grande above the middle valley. Below it, Albuquerque and the middle valley's irrigators draw on the river before what is left reaches the lake. Rio Grande at Otowi Bridge carries the daily flow against its median for the date.

How low it has been before

The record low is 4,258.03 feet on Aug 6, 1954, in the drought of the 1950s, when the lake ended 1951 at 4,270.1 feet and 1956 at 4,272.59 feet. It fell low again in 1964 (4,275.51 feet on Sep 9) and 1971 (4,271.19 feet on Sep 7). Each time a wet run refilled it: from 4,272.59 feet at the end of 1956 to 4,362.7 feet at the end of 1958, and from 4,305.67 feet at the end of 1978 to the near-full years of the mid-1980s. The record high is 4,409.19 feet on Jun 16, 1942, the year the reservoir first reached full pool. Elephant Butte Reservoir water level carries the daily reading and storage, and what carryover storage is explains why the Sep 30 figure in the table is the one irrigation districts plan around.