The Mono Lake 2024–2025 lake level forecast report

Each spring the Mono Lake Committee’s team of Mono Basin modelers and hydrology experts uses the lake level on April 1 together with the Mono Basin snowpack numbers and similar-year hydrological statistical data to produce the Mono Lake Committee lake level forecast for the runoff year ahead. You can download the full Mono Lake 2024–2025 lake level forecast here.

Since December 2022, Mono Lake rose 5.3 feet due to an “Extreme-Wet” 2023 and average precipitation this past winter. On April 1, 2024 the surface elevation was 6383.7 feet above sea level. This forecast shows that the most probable lake level (with 1999 climate) for April 1, 2025 is 6383.6’.

April 1 was the start of the current runoff year, which is classified as a “Normal” year type. The graph below shows the range of likely Mono Lake elevations for the runoff year. The range of projections (light blue shading) is produced by the Mono Lake Committee’s modeling of hydrologic sequences using historic near-average runoff years, with levels based on 1999 conditions shown as a likely scenario (solid blue line).

For the first time in 30 years the Los Angeles Department of Water & Power plans to divert and export less water, 4,500 acre-feet, than the maximum export allowed (16,000 acre-feet). The graph below shows the impact of this decision to be as much as 1/4 foot of elevation. The dotted line in the graph below represents what the lake level forecast would have been with 16,000 acre-feet of surface water exports.

Reference lake levels and exports

  • State Water Board mandated lake level to protect Mono Lake: 6392 feet above sea level.
  • Lake level rise from April 1, 2024 needed to achieve the mandated level: 8.3 feet.
  • Groundwater exports in the form of a constant flow in the Mono Craters Tunnel, total about 5,000 acre-feet of additional water to leave the Mono Basin annually.

Top photo by Geoff McQuilkin.