Preparing for Climate Change in California’s East Bay Municipal Utility District
The East Bay Municipal Utility District (EBMUD) has developed mitigation and adaptation strategies to address the effects of climate change on water resources in the San Francisco Bay Area. These strategies include reducing greenhouse gas emissions, incorporating climate change into planning efforts, and the creation of a monitoring and response plan to inform planning for infrastructure and water quantity and quality in the face of climate change. EBMUD released their climate plan in June 2020.
Located in the San Francisco Bay Area of California, the EBMUD serves approximately 1.4 million consumers in over 20 cities. The District obtains over 95% of its drinking water supply from the Mokelumne River; to supplement this supply, the District, along with the Sacramento County Water Agency (SCWA), invested in the Freeport Regional Water Project to divert water from the Sacramento River into the East Bay system.
Climate change impacts of concern to the Bay Area include loss of snowpack, changes in freshwater flow patterns, changes in precipitation amount and timing, and increased temperatures. The District is working to stay up-to-date on the science and assessment of climate change effects in the Mokelumne and East Bay watersheds, and examining these impacts in terms of consequences for water supply and demand and potential vulnerabilities of the system’s infrastructure.
Many of the assessments were conducted with the support of the Lawrence Livermore National Lab, including:
- hydraulic and hydrologic modeling to determine potential impacts on river flow;
- water temperature modeling to evaluate effects on fisheries and water quality; and
- investigating the reliability of infrastructure to deal with rising sea levels and water supply.
The last assessment is of particular concern because the aqueducts running from the Mokelumne River cover about 90 miles of the Bay Delta, which is currently below sea level and protected by levees; the aqueducts and levees are therefore both highly vulnerable to sea level rise. The long-term solution is to bury the aqueducts under the Bay Delta for a 10 to 15 mile stretch; this construction would be very expensive (~$500 million) but may be necessary. Less expensive and more short-term solutions that EBMUD has used include:
- the addition of climate change to EBMUD’s strategic plan;
- creation of the Climate Change Monitoring and Response Plan to help EBMUD evaluate the impacts of climate change on water supply and implement mitigation and adaptation strategies;
- upgrading wastewater pumps and pipes to reduce the risk of floodwater infiltration;
- collaborating with the Upper Mokelumne River Watershed Authority to thin trees to reduce stand density and associated risk of catastrophic wildfires and restore meadows to improve water supply and quality; and
- creating a long-term water supply planning effort built out to 2040 that incorporates uncertainty.
As part of the development of the Water Supply Management Program 2040, EBMUD evaluated potential water supply vulnerabilities for its service area. The scenarios evaluated included a 2°C temperature increase, a 4°C temperature increase, and a 20% reduction in precipitation. Every scenario indicated potential decreases in water supply over time and highlighted the need for a variety of adaptation approaches, ranging from water conservation to supplementary water supply projects (e.g., groundwater banking, water transfers). Complete vulnerability results are available in the 2015 Urban Water Management Plan.
In June 2020, EBMUD released their which highlights key climate-related vulnerabilities as well as climate mitigation and adaptation strategies for EBMUD’s wastewater assets. The District used the RCP 8.5 scenario, which assumes no reduction in greenhouse gas emissions. Primary risks to wastewater assets in the Bay Area include sea level rise (~4.7–24” by 2050, ~16.5–65.7” by 2100), groundwater level rise (~12” by 2050, ~36” by 2100), increases in mean temperatures (+4.4–7.2°F by 2100), and more intense rainfall. The plan prioritizes reducing energy consumption, modifying facilities to accommodate sea level rise (e.g., infrastructure elevation, using waterproofing materials in construction, and re-routing flows around at-risk systems when possible), increased collaboration with others in the area, such as municipal and state agencies, the Port of Oakland, and flood control districts. The plan identifies protective measures such as barriers to be a “last resort” choice as the associated costs are very high.
Outcomes and Conclusions
The EBMUD has already taken steps to plan for and respond to climate change. The District engages in monitoring and assessment activities in order to refine mitigation and adaptation approaches to protect the water supply system.
Project File (s)East Bay Municipal Utility District: Climate Change Freeport Regional Water Project Water Supply Management Program 2040 Urban Water Management Plan
Gregg, R. M. (2021). Preparing for Climate Change in California's East Bay Municipal Utility District [Case study on a project of the East Bay Municipal Utility District and the Lawrence Livermore National Lab]. Version 2.0. Product of EcoAdapt’s State of Adaptation Program. (Last updated August 2021)