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The Metropolitan Water District of Southern California

Drought Contingency Plan

​In December 2017, the Department of Water Resources’ Reclamation Commissioner Brenda Burman called on the seven Colorado River Basin States and water entitlement holders in the Lower Colorado Basin to continue developing Drought Contingency Plans in response to ongoing historic drought conditions in the Basin and reduce the likelihood of Colorado River reservoirs – particularly Lake Powell and Lake Mead – further declining to critical elevations.

All seven Colorado River Basin States diligently worked on a set of draft DCP greements that would implement Drought Contingency Plans in the Upper and Lower Basins. The agreements would include an Upper Colorado River Basin Drought Contingency Plan and a Lower Colorado River Basin Drought Contingency Plan. Read the Final Review Draft of the Upper and Lower Basin DCPs.

This would provide flexibility to meet local water demands. By agreeing to moderate voluntary cutbacks under the DCP, the Lower Basin states can significantly reduce the chance of severe shortages if lake levels were to reach certain critical points in coming years.

The plan was signed on May 2019.  Read the General Manager's statement regarding this historical event.

The Metropolitan Water District has been a leader in this ongoing collaboration and is committeed to working cooperatively within California and beyond to ensure the plan's success.

Water Supplies

California is one of seven western states that rely on water from the Colorado River or its tributaries. For years, California used more than its basic apportionment of 4.4 million acre-feet of water a year, primarily by relying on surplus supplies and water apportioned to but unused by Arizona and Nevada.

In the late 1990s, as Arizona and Nevada began to fully use their apportioned supplies, and federal authorities, along with other Colorado River Basin states, challenged California to develop a comprehensive plan to reduce its reliance on surplus Colorado River supplies and ultimately live within its basic apportionment.

In response, California developed the draft California Colorado River Water Use Plan​  to gradually reduce the state’s use to its apportionment of 4.4 million acre-feet by 2017. The plan described key terms which were included in the 2003 Quantification Settlement Agreement, and the 2003 Colorado River Water Delivery Agreement which established water budgets for Imperial Irrigation District and Coachella Valley Water District to help facilitate water transfers from farms to cities.

Exchanges & Water Banking

The projects and programs Metropolitan has developed to restore reliability of Colorado River supplies cover a wide range of topics. In addition to transfers, exchanges and groundwater banking, Metropolitan has developed specialized conservation programs whereby Metropolitan invests in conservation programs outside its service area and receives the water that is conserved. The conservation programs vary and include canal lining, land fallowing, crop rotation and irrigation improvements, among other options. In addition, Metropolitan has collaborated with other parties in the Colorado River basin to bank water in surface reservoirs. Known as “Intentionally-Created Surplus" these surface water banking programs have allowed Metropolitan to take advantage of existing surface reservoirs to store conserved supplies for later use.

Water transfers, exchanges and water banks are important water management tools that allow agencies to augment local supplies and utilize external distribution and storage systems. Metropolitan’s water portfolio includes a number of water transfer and banking agreements with state, federal, public and private water districts and individuals.

Current banking/transfer programs that deliver supplies via the Colorado River Aqueduct include:
  • Imperial Irrigation District Conservation Program
  • Palo Verde Irrigation District Land Following and Crop Rotation Program
  • Quantification Settlement Agreement Transfers

Additional projects funded jointly with Southern Nevada and Central Arizona:

  • Warren Brock Reservoir
  • Yuma Desalting Plant
  • Mexico Water Treaty Pilot Conservation Project (Minute 319)

Planning for Long-term CRA Supplies

Metropolitan’s principal goal in investing in these supply programs is to provide a full Colorado River aqueduct to meet Southern California’s water needs in dry years. Ultimately, however, climate change and legal disputes could make meeting that goal more challenging in the future. To provide reliable supplies in the future, Metropolitan is coordinating with other basin states to implement recommendations of the Colorado River Basin Study and working to preserve the Quantification Settlement Agreement for the Colorado River.

Colorado River Basin Study
Released by the Bureau of Reclamation and the Colorado River Basin states in December 2012, the Colorado River Basin Study evaluates water supply and demand in the Colorado River Basin over the next 50 years, and identifies options and strategies to meet the demand gap. Options identified in the study include:    

  • Increases in urban and agricultural water-use efficiency
  • Agricultural-to-urban water transfers
  • Brackish water desalination
  • Weather modification through cloud seeding
  • Removal of non-native species
  • Seawater desalination

While some of the options can be developed quickly, others could take decades to realize. Metropolitan is working with the Colorado River Basin states and the federal government to evaluate which options are the most promising and to implement them.

Delta Water Supplies

Water flowing through the Delta, supplies 30 percent of Southern California’s drinking water, 33 percent of the Bay Area’s, and up to 90 percent of the Central Valley’s drinking and irrigation water. Some communities are 100 percent dependent on the Delta for their water supplies.

Over the years, the Delta’s ecosystem has deteriorated, and its 1,100-mile levee system is increasingly vulnerable to failure caused by earthquakes, floods and other forces of nature. The decline of the Delta’s ecosystem has led to historic restrictions in water supply deliveries. The result is a pressing two-fold need: improve California’s water reliability and restore the Delta’s fragile ecosystem.

The Delta was once a vast marshland covered with tulles and teaming with wildlife. Settlers, lured at first by the gold rush of the mid 1800s, built levees to drain and reclaim the land.

Environmental Conflicts

Tidal wetlands are an important source of food and shelter for fish such as delta smelt that live year-round in the estuary.  Adjacent floodplains such as the Yolo Bypass are feeding grounds for young salmon on their journey to the Pacific Ocean.

Today, about 95 percent of the original wetlands and original floodplains are no longer part of the Delta ecosystem due to levee construction and other human activities.  Yet it remains California’s most important estuary and a vital environmental resource, home to more than 750 plant, bird, animal, and fish species.

Water Supply Risks

Today’s Delta region faces numerous threats that are projected to worsen.  Absent intervention, California’s water supply system and the Delta ecosystem are at risk of collapse and are projected to worsen due to a variety of natural and man-made stressors.


There are several faults running through the San Francisco Bay Area region that could affect the Delta. According to the U.S. Geological Survey, there is a 66 percent chance of a magnitude 6.5 earthquake hitting the Bay-Delta region by 2032. Such an earthquake could cause the levees that surround the Delta islands to collapse, flooding up to 30 Delta islands. Salt water from San Francisco Bay could migrate eastward, rendering the Delta as an undrinkable source of water supply for up to three years until extensive repairs are completed. The statewide economic costs of such an event could exceed $40 billion.

Sea-level Rise

The official state guidelines call for planning efforts in the Delta to assume a 16-inch rise in sea level by 2050 and 55 inches by 2100. Rising sea levels will not only put greater pressure on the Delta’s dirt levees, but will cause seawater to intrude further inland impacting water quality.


When levee construction beginning in the 1850s transformed the Delta from marshland to farmland, it exposed the peat soils, which began to oxidize, compact and blow away. This process of subsidence continues. What were once islands are now more like bowls, constantly depending on levees. The total volume of soil lost, or the void currently below sea level, is in excess of 3.5 million acre-feet or almost 8,000 Rose Bowl stadiums. As the subsidence continues, the water pressure on the levees becomes greater.

Fishery Declines

While numerous scientific panels have attributed the decline in the Delta’s health to numerous causes, enforcement efforts to date have focused almost exclusively on curtailing public water supplies from Delta facilities. Export agencies experienced cutbacks to pumping dating back to 1991 due to Endangered Species Act requirements. During the last two decades export pumping to the State Water Project and Central Valley Project has been reduced by more than 2 million acre feet.

Non-native Species

More than 95 percent of the biomass in the Delta is non-native. Striped bass, Black bass, Asian clams and many other invaders, large and small, are either eating the native populations or the foods on which they rely.

In this highly-altered environment, the introduced species are over-running the native species and are a key factor in reducing populations of some endangered species.

Public water agencies like Metropolitan are promoting a more comprehensive approach to restoring the Delta as a way to restoring reliable water supplies long-term.

Delta Conveyance

About 30 percent of the water that flows out of taps in Southern California comes from Northern California via the Sacramento-San Joaquin Delta.  The state is heading an effort to modernize the water system in order to maintain supply reliability and provide environmental benefits.  Metropolitan made an historic decision to invest in a twin tunnel project in 2018.  Governor Newsom's project vision takes a one-tunnel approach. 


Learn more about Delta Conveyance.

Delta Islands

Bay-Delta Live

Bay-Delta Live is an online data hub used by resource managers, scientists, conservationists, policy makers, academics, local community interests, and other stakeholders. The goal of the project is to expand open and transparent sharing of information to better understand the complex and dynamic ecosystem of the Sacramento-San Joaquin Bay Delta. Bay-Delta Live provides information from multiple sources using enhanced visual interfaces. This site is supported by state and federal water, wildlife and natural resources organizations, science workgroups, The Metropolitan Water District of Southern California, State and Federal Water Contractors Water Agency and others.