Get Full Government Meeting Transcripts, Videos, & Alerts Forever!
Get email alerts on the Mono Lake Modeling topic
No spam. Unsubscribe anytime.
UCLA modeling finds climate and LADWP exports limit Mono Lake recovery; stakeholders call for hearing and export adjustments
Summary
A UCLA water‑budget model presented to the State Water Resources Control Board found climate change has likely lowered Mono Lake’s level (≈2 ft since 1994) and that current export rules make meeting the board’s 1994 management level unlikely; stakeholders and agencies urged the board to schedule a hearing to revisit LADWP diversion criteria and explore export reductions or pauses.
The State Water Resources Control Board received a multi‑panel briefing March 17 on new modeling that integrates climate projections into Mono Lake water budgets and on analyses from existing basin models. UCLA’s Center for Climate Science presented a probabilistic, downscaled model showing that rising evaporation from climate change has already lowered Mono Lake levels and that, under current export rules, meeting the board’s 1994 management level (6,392 ft) is unlikely over coming decades.
UCLA lead Alex Hall and hydrologist Benjamin Bass summarized three principal findings: climate change has likely already reduced present‑day Mono Lake levels; under existing export criteria achieving the lake‑level objective is unlikely; and carefully designed export adjustments can meaningfully improve recovery odds. Using an ensemble of 11 downscaled climate model projections with multiple emissions scenarios, UCLA reported, for example, roughly a one‑in‑three chance of reaching the transition target by 2064 under existing exports versus a roughly two‑in‑three chance with no exports. The team emphasized probabilistic results and the value of dynamic, revisable export rules rather than a one‑time fixed regime.
Presenters noted the UCLA model will undergo formal peer review and that the UCLA team is developing an interactive user interface to allow stakeholders to test export scenarios; staff said the interface is not yet publicly released but could be hosted and made available after quality control and documentation.
LADWP and other modelers presented complementary tools. LADWP described eStream, a daily operational model used for planning and the 2013–2021 facilitated process; the Mono Lake Committee and collaborators described the updated Vorster model and collaborative wrapped runs; and CDFW described an informational Excel simulation to illustrate how lake level would have responded had exports been returned. Presenters generally agreed the models reproduce historical water levels and that the models’ bookends (no exports vs status quo) bracket plausible outcomes. The primary new contribution from UCLA is the explicit climate‑change lens and the probabilistic framing of recovery likelihoods.
Tribal representatives, local officials, air‑quality agencies and conservation groups urged action. Dean Tonina, an elder with the Mono Lake Kootsuk'auba Tribe, described cultural and subsistence impacts from exposed lakebed and dust, and asked for tribal inclusion in any process on tribal beneficial uses. The Great Basin Unified Air Pollution Control District and California Air Resources Board pointed to PM10 exceedances tied to exposed playa as a public‑health concern that improved lake levels would mitigate. The Mono County Board of Supervisors, the Mono Lake Committee, Audubon, Coastkeeper, Sierra Club and other organizations urged the board to schedule a hearing under Decision D‑16‑31 to revisit diversion criteria; several commenters recommended pausing or sharply reducing exports until the lake recovers and pointed to LA local water projects (for example, Tillman groundwater replenishment) as partial offsets.
Board members discussed next steps. Several members voiced support for scheduling a hearing under the 1994 decision’s provision that permits revisiting diversion criteria if the transition level was not reached by the stipulated date. Board staff and members suggested a two‑track immediate program: (1) near‑term staff‑led technical workshops (model access, peer review status, shared assumptions, tribal inputs) to refine outstanding issues; and (2) preparation of options for a formal hearing or other administrative path (including scoped, time‑limited proceedings or adaptive management frameworks). No formal vote was taken to schedule a hearing during this meeting.
What’s next: staff will convene technical engagement and return to the board with options (staff and board members discussed bringing recommendations back later in the year). UCLA will submit a manuscript for peer review and expects a public interface for scenarios after internal review and board coordination.
Representative quote: "Climate change has likely already reduced Mono Lake level…under existing export criteria, meeting lake level objectives is unlikely…if we adjust exports, it can improve the likelihood of recovery," said Benjamin Bass (UCLA).
