Historic State Water Board action halted ecosystem collapse, but lake is still only halfway to management level
On September 28, 1994, the California State Water Resources Control Board voted unanimously to approve Decision 1631, amending the water licenses of the City of Los Angeles in order “to establish fishery protection flows in streams tributary to Mono Lake and to protect Public Trust resources at Mono Lake and in the Mono Lake Basin.”
The crowd in the Sacramento hearing room stood in a genuine and enthusiastic ovation, a rarity for state agency decisions. Board member Marc Del Piero pronounced: “Today we saved Mono Lake.”
Remarkably, not one of the parties that participated in the hearing process that led to D1631 appealed the decision—most notably, not even the Los Angeles Department of Water & Power (DWP). D1631 provided water for the lake and streams. At the same time the Mono Lake Committee had helped to secure water solutions for Los Angeles that included conservation programs and millions of dollars in state and federal funding to develop local supplies. A decades-long water battle had ended with all parties agreeing to stop fighting and move forward to implement the solution.
Using science to strike the balance
Back in 1993 the State Water Board prepared an Environmental Impact Report that gathered extensive scientific information over three years covering the impacts of water diversions and how Mono Basin resources would respond at a variety of lake levels. Forty-six days of hearings—with 125 witnesses and extensive cross examination—dug into the topics as the Board searched for a balance between urban water supply and protection of lake and stream resources.
For the streams, D1631 established a mandatory minimum flow regime that would fulfill the legal obligation to keep fish in good condition downstream of DWP’s diversion dams, correcting prior, full-flow diversions that courts had deemed illegal. The Board ordered a stream and fisheries restoration program as well, because decades of total diversions had left the streams as bare gravel washes, eliminating once-famous fisheries and causing streamside forests to collapse. The stream restoration program continues today under the leadership of independent experts and has achieved significant progress, with riparian vegetation returning and fish populations recovering.
Starting in the early 2000s a decade of focused scientific studies led to detailed science-based recommendations for a sophisticated pattern of stream ecosystem flows that mimic the natural snowmelt hydrograph. The Committee, DWP, California Trout and the California Department of Fish & Wildlife reached a settlement in 2013 on terms to implement these flows. They were ordered by the State Water Board in 2021 and today they are accelerating restoration. However, more work remains to be done, including monitoring and adaptive management, and construction of the essential, and now delayed, Grant Lake Reservoir outlet.
For Mono Lake, D1631 set a sustainable long-term average management level of 6,392 feet above sea level, reducing DWP diversions that had caused the lake to fall 45 vertical feet, lose half its volume, and double in salinity. The management level will protect a host of Public Trust resources by reducing salinity so the ecosystem can thrive, improving air quality by covering exposed dry lakebed and reducing toxic dust storms, submerging the landbridge to protect the nesting California Gull colony, and providing a buffer of water to protect the lake in the face of droughts and climate change. The cultural resources of the Mono Lake Kootzaduka’a Tribe will be better protected. The productivity of brine shrimp and alkali flies—the core of the Mono Lake food web—will recover, ensuring ample food for millions of nesting and migratory birds.
D1631 put limits on DWP’s water diversions where none had previously existed, and those limits were immediately effective in halting the lake’s decline and worsening situation. Hydrology models show that, left unchecked, DWP’s diversions would have lowered the lake another 40 feet below today’s elevation, pushing salinity past the point of causing ecological collapse. Thirty years later, we can celebrate that we have Mono Lake at all thanks to the State Water Board’s action to protect the Public Trust.
Promises still left to fulfill
Reflecting on D1631 today, its significance and accomplishments are clear, but it is also clear that its promise to Mono Lake remains unfulfilled. The lake has only recovered halfway to the mandated Public Trust lake level, and the serious problems that level was chosen to address—from dust storms to ecosystem impairment—remain.
The Board expected that it would take about 20 years for the lake to rise to 6,392 feet, yet Mono Lake is nine feet short and a decade overdue. Analysis and 30 years of observation confirm that the lake is stuck at this low level because of the volume of ongoing annual stream diversions.
Hydrology modeling shows that reducing water diversion volumes will allow the lake to achieve the 6,392-foot level. Modeling also shows that changing the structure of the rules that govern stream diversions can accomplish a lot.
Working with LA to identify times of greater value for Mono Basin water can help—diversions have greater importance for the City’s supply in drought years, for example, so wet year cutbacks are easier for the City to handle. Diversion cutbacks are currently assigned to fixed lake threshold elevations; moving to dynamically adjusting thresholds that rise together with the lake is a better way to lock in lake level gains as they happen and “ratchet” the lake upward to 6,392 feet more effectively.
Fortunately, D1631 contains a provision for the current situation. It provides for the State Water Board to hold a hearing to adjust stream diversions if the lake has not recovered on schedule. Preparations for this hearing are well underway at the Committee and focus on finding water solutions for both Mono Lake and Los Angeles to ensure both can thrive.
Progress toward a hearing
Last year, at a workshop held by the State Water Board, Mono Lake Committee members and experts showed up in the hundreds and wrote letters in the thousands—communicating the urgency of the situation and asking the Board to advance the hearing process.
The State Water Board has since made Mono Lake a priority item in its workplan. And this fall the Board received the first draft of a Mono Basin hydrology model developed by the UCLA Center for Climate Science. This model will help the Board answer questions about future climate and diversion scenarios that would allow Mono Lake to reach the management level.
The wheels of state agencies can turn slowly, but they are now in motion toward a hearing on Mono Lake. While we are still awaiting word on a specific hearing date, we are heartened by the great interest in this issue shown in Los Angeles and throughout California as people are realizing that Mono Lake still needs saving.
Today, as in 1994, the Mono Lake Committee is dedicated to helping Los Angeles secure more water conservation measures. LA leaders have already made significant commitments to rapidly implementing environmentally responsible local supply projects such as stormwater capture, turf replacement, and water recycling.
The people of LA are calling for the same solutions. In front of the LA City Council Energy & Environment Committee, East Yard Communities for Environmental Justice leader mark! Lopez talked about “the imperative to stop relying on imported water” from Mono Lake for the sake of Los Angeles.
Seeking joint solutions, Mono Lake Committee and DWP staff engaged in a collaborative hydrology modeling effort at the request of Los Angeles Deputy Mayor of Energy & Sustainability Nancy Sutley.
Although there are many signs that DWP’s attorneys are preparing to contest any water diversion changes at a hearing, we appreciate further productive Mono Lake collaboration with City leaders. Mayor Karen Bass chose to not increase diversions this year, in response to a request from the Committee and a coalition of Los Angeles community leaders. And the City Council honored the anniversary of D1631 by proclaiming Mono Lake Day in Los Angeles.
Thirty years ago, the State Water Board acted to protect Mono Lake for the people of California and to preserve and restore the remarkable ecosystem we know and love. This anniversary is a moment to celebrate a great victory for Mono Lake—and to reaffirm our commitment to working to implement Decision 1631’s promise of protection into a lake lapping at the healthy 6,392-foot elevation shoreline. True success for Mono Lake comes when D1631’s expectations become landscape realities, with a thriving ecosystem, safe bird habitat, clean air, and a secure future.
This post was also published as an article in the Fall 2024 Mono Lake Newsletter. Top photo by Juniper Bishop.