Restoration Chronology for the Mono Basin
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Restoration Chronology

This chronology does not detail all of the projects and actions that were taken on the ground; instead it summarizes the legal, political, structural, and hydrological events influencing the restoration of Mono Lake and the streams diverted by LADWP.


Following the extremely wet 1982-83 winter season, high spring run-off overflowed Grant Lake Reservoir and spilled over into the dry streambed of Rush Creek. Late in the 1982 season, there was still more runoff than LADWP could divert through its aqueduct. This bounty led to year-round flows in Rush Creek for the first time in many years, reestablishing fish populations. Lee Vining Creek also spilled high flows during the summer of 1983, but the flows were intermittent and fish did not get established year-round. Mono Lake rose 9 feet by mid-1984.


The Public Trust Decision by the California Supreme Court declared that the State Water Resources Control Board had failed to uphold its public trust responsibilities when it granted the LADWP licenses to export water from the Mono Basin. As with the 1982-83 winter season, the 1983-84 winter season also was wet, and Rush Creek received continuous flows through a second winter.


By spring, the streamflows had diminished to the point that the L.A. Aqueduct could once again hold all the water. Later that fall, LADWP planned to "turn off" Rush Creek. California Trout initiated litigation, arguing that the State Water Board-approved water diversion licenses violated Fish & Game code section 5937, which requires water releases below dams to protect fish. A court-ordered temporary injunction resulted in minimum year-round flows in Rush Creek until the litigation was concluded. (Similar court orders provided for minimum flows in Lee Vining Creek in 1986 and for Walker and Parker creeks in 1990.) Ultimately, these cases were coordinated with the Mono Lake public trust litigation under the jurisdiction of the El Dorado Superior Court.


The Third District Court of Appeals issued its decision on litigation initiated by Caltrout, known as CalTrout II, which ordered interim flows in all four of the diverted streams and ordered DWP "to reestablish and maintain the fisheries which existed in [Rush and Lee Vining creeks] prior to its diversion of water," setting the stage for restoration.


A subsequent El Dorado Superior Court order resulted in the creation of a Restoration Technical Committee (RTC), comprised of those actively engaged in the ongoing litigation, including LADWP. The task of the RTC was to set restoration policy and authorize interim restoration activities while the State Water Board completed the Mono Basin EIR and reached its decision. Debate within the RTC focused on the degree and type of intervention. Given the relatively low stream flows ordered by the court, which did not provide sufficient energy for the stream to recreate its former processes, the RTC eventually chose a mechanical approach to restoration. Some of the work completed under the RTC washed out or was subsequently modified by high flows in 1995 and 1997. The RTC also oversaw development of reports that provided a strong base of scientific information used subsequently by the State Water Board in its deliberations on Mono Lake. The RTC disbanded when the State Water Board issued its Mono Lake decision in 1994.


The State Water Board's Decision 1631 (D.1631) set a target lake level for Mono Lake, established minimum flows and annual peak flows for the creeks, and ordered DWP to develop restoration plans for the streams and for waterfowl habitat.


The Mono Lake Committee began planting trees—1500 along Lee Vining Creek that year—and reading groundwater levels in piezometers. The first year of high flows unrestricted by DWP gave the stream scientists evidence that mimicking natural flows would restore the streams. Mono Lake began rising and after several wet years rose 12 feet by mid-1999.


DWP released its Mono Basin Restoration Plans for the restoration of (a) the four streams historically diverted by DWP (Rush, Lee Vining, Walker and Parker creeks) and (b) waterfowl habitat. These plans were based on the work of independent scientists and incorporated most but not all of the scientists' recommendations. A number of parties argued that DWP's plans were inadequate to achieve the restoration called for by D.1631, particularly (in the case of the stream plan) with regard to the peak flows proposed and to "termination criteria," the prediversion condition against which to measure restoration progress.


In January, a rain-on-snow flood brought a very high flow to Lee Vining Creek that made many changes to the stream channel. Even though the Mono Basin Restoration Plans were still pending approval before the State Water Board, LADWP initiated baseline restoration monitoring on the streams. In this first season, restoration consultants hired by LADWP began mapping select reaches of Rush and Lee Vining creeks and testing fish population monitoring techniques. In the fall, waterfowl surveys around Mono Lake were undertaken as well.
Related Mono Lake Newsletter articles:
Winiter 1997: DWP Policy Switch Leads to Dry Grass at Cain Ranch
Spring 1997
: DWP Clarifies Cain Ranch Irrigation Policy


After hearings, which included examination of a Settlement Agreement signed by most but not all parties, the State Water Board issued its order on restoration at Mono Lake. Key features of the final Mono Basin Restoration plans include: flow regimes on the streams that are based on the natural hydrograph; a stream monitoring program that will be the basis for adaptive management of stream work over time and the means of measuring when restoration is complete; reopening of certain abandoned secondary channels on Rush Creek; raising the lake to 6,392 feet for waterfowl habitat; improving existing freshwater ponds for migrating waterfowl; and annual aerial monitoring of waterfowl and waterfowl habitat. LADWP's restoration monitoring, initiated by restoration consultants in 1997, continued.
Related Press Release:
Summer 1998: State Decision Offers Good News to Mono Lake


Mono Lake Newsletter articles:
Summer 1999: DWP-hosted meeting ushers in new era of communication
Fall 1999: Return Ditch Capacity Frustrates Restoration


Mono Lake Newsletter articles:
Winter 2000: Channel-openings for 2000 field season to be discussed this spring
Fall 2000: Two Mono Basin Meadows Go Without Irrigation


Mono Lake Newsletter articles:
Summer 2001: Rush Creek Return Ditch Update
Fall 2001: Rush Creek Return Ditch Rehabilitation Underway


The mile-long Mono Gate One Return Ditch (MGORD) is the only reliable way to release a controlled flow down Rush Creek below Grant Lake Reservoir. The capacity of the ditch was upgraded to 380 cubic feet per second (cfs), a required normal-year peak flow. Previously the capacity was 160 cfs and prevented Water Board-ordered flows from being released. A flow of 380 cfs was tested in 2004.
Related Mono Lake Newsletter articles:
Summer 2002: Return Ditch Delayed; Channels Opened
Fall 2002: Return Ditch, Channel Openings, Burn Program, Waterfowl Monitoring


Mono Lake Newsletter articles:
Spring 2003: Mono's Tributary Streams as Songbird Habitat: What is the Appropriate Measure of Restoration Success?
Summer 2003: Full Diversions on Lee Vining Creek


In the late summer and Fall LADWP installed a new gate in the Lee Vining Diversion Dam. This gate allows automatic and remote control of water diversions, and can be lowered to empty the diversion pond and allow sediment to pass downstream. A sediment bypass system was ordered to be implemented by the Water Board in 1998. The new technology also ended the periodic minimum flow violations caused by the design of the original 1940 structure.
Related Mono Lake Newsletter articles:
Winter 2004: Runoff Forecasting; Return Ditch Flow Test; Fish Movement Study; Tree Planting
Summer 2004: Status Report 10 Years after D1631: Is Mono Lake Restored? Have the Creeks Recovered?; Return Ditch Flow Test
Fall 2004: Los Angeles Upgrades Lee Vining Creek Diversion Dam ; Peak Flows, Bottomland Channels; Willow Flycatchers


Back to back wetter than average years provided a tremendous leap forward for the stream restoration program. Four drier-than-average years since 2000 had caused the deferring of some restoration work (such as channel reopenings). On Rush Creek, two years of Wet-normal peak flows (2004 and 2005) and one year of Wet peak flows (2006) have provided dynamic energy to the stream that has been missing since the late 1990s. Monitoring data from these three years have provided additional information for the restoration effort.
Related Mono Lake Newsletter articles:
Fall 2005: Highest Peak Flows Since 1998
Spring 2006: 12 Years and Counting: Mono Basin Restoration Progress Report; The Role of Adaptive Management ; Plans to Manage Invasive Plant Species
Summer 2006: Grant Lake Reservoir Spills


The second-driest runoff year on record and the first officially "dry" year since 1994 resulted in the first time since the Mono Lake Decision that no peak flows were delivered to Rush and Lee Vining Creeks.

The Mono Lake Committee and LADWP jointly submitted a "Status of Restoration Compliance" (SORC) Report to the Water Board. The SORC Report, updated annually, summarizes all of LADWP's requirements and the status of completion of each item.
Related Mono Lake Newsletter articles:
Winter 2007: What we've learned about vegetation recovery
Spring 2007: Status of Restoration in the Mono Basin
Summer 2007: Excitement on Rush Creek despite a dry year
Fall 2007: Two Rush Creek Channels Flow Again


Mono Lake Newsletter articles:
Winter-Spring 2008: State Water Board approves low flow variance for Rush Creek; Rush Creek variations: high times and deep blues for the Mono Basin's endangered songbird; Lowest streamflow in 15 years; lowest runoff in 30
Summer 2008: Restoration flows, facilities, and future needs; Normal Runoff Year streamflows to test aqueduct facilities to limit
Fall 2008: Flow study on Rush Creek; Dry conditions in a "Normal year" lower Grant Lake Reservoir levels and challenge Jeffrey pine seedlings


LADWP rebuilds Mono Gate One, the outlet to Rush Creek from Grant Lake Reservoir, to safely and reliably handle 380 cfs, a normal-year peak flow.
Starting in 2009, we are posting restoration updates on the Monologue.


LADWP conducts annual monitoring of restoration progress and hosts semi-annual restoration meetings attended by interested parties. The monitoring is summarized in annual compliance reports and includes:

  • Lake level and stream flow measurements

  • Vegetation transects at key sites around the lake and along the streams

  • Aerial photography of stream and lakeshore changes

  • Geomorphic mapping of stream channel changes

  • Fish population studies

  • Waterfowl surveys



Restoration Information

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Frequently Asked Questions

Diversion Impacts

Restoration Orders

1982-Present Restoration Chronology

1979-1998 Legal Chronology

Annual Compliance Reports

What About Mill Creek?