Current Water Supply Levels

Current Water Supply Update:  

• During the drought, Sonoma Water is carefully managing existing water supplies in both Lake Mendocino and Lake Sonoma.
• To date, Sonoma Water has reduced diversions from the Russian River by 24 percent compared to last year.
• Despite the recent rainstorms, the region is still in a drought.  Read drought condition updates here.

Rainfall, Weather, and Streamflow Data

• The recent atmospheric rivers brought much-needed rain to our region and saturated the soil, which allowed runoff to into our reservoirs.
• Reservoirs are still at historic lows and many more storms are needed to bring their storage levels up to normal and bring an end to the drought.
• This initial storm was not a drought buster, we still need conservation from our community.
• Ongoing conservation is still needed in order to save the water we did receive and prepare for future possible dry months ahead.
• Local cities and water districts continue to implement their water shortage plans, residents should continue to follow those plans .
• The Governor’s Conservation Order still remains in effect calling for 15-percent conservation 
• If you haven’t already, please turn off your outdoor irrigation – that alone will help save our water supplies and save water. For other saving water ideas and rebates for water-efficient appliances, visit savingwaterpartnership.org
• Sonomawater.org provides updated reservoir levels and drought updates 

National Weather Service weather forecast for Santa Rosa

Current streamflow gauge reading for Russian River and tributaries - Sonoma OneRain website

Sonoma OneRain - Real-time Rainfall, River-Stream, and Reservoir Data

Scheduled releases - Lake Mendocino on CA Data Exchange Center Website

Scheduled releases - Lake Sonoma on CA Data Exchange Center Website

Precipitation map for the current Water Year (October 1 - Present)

General Updates

1. On November 16, 2021, Sonoma Water filed Temporary Urgency Change Petitions (TUCPs) with the State Water Resources Control Board (State Water Board) Division of Water Rights (Division) requesting a change in the hydrologic index used to establish the water supply condition in the Russian River watershed. Sonoma Water's water rights permits require the maintenance of minimum instream flows downstream of Lake Mendocino and Lake Sonoma.  On December 10, the State Water Resources Control Board issued an order that approved the requested changes of the TUCPs with various terms and conditions. Read more here. 
    
2. Sonoma Water, Water Advisory Committee seek 20 percent voluntary conservation.
    
3. Sonoma County Board of Supervisors on April 27 declared a local drought emergency.  View the agenda item and proclamation. Read the press release.
    
4. Governor Newsom signed a State of Emergency Proclamation for Sonoma and Mendocino counties. Read the proclamation. Read the Governor's press release.  Read Sonoma Water's statement.
    
5. The Russian River watershed is in a historic drought.  The watershed has experienced extremely dry weather conditions this water year (WY-2021). A water year begins of October 1 and ends on September 30^th of the following year. This is the second consecutive dry water year coming on the heels of WY-2020, which was also very dry. View drought monitoring data for Santa Rosa and Ukiah.
6. The current drought on record is 1976/1977 when Ukiah received just 16.12 inches of rainfall. As of today, Ukiah has recorded only 12.24 inches of rainfall this year, slightly ahead of 1976/1977 when Ukiah measured 11.27” through April 15.  On average, Ukiah receives 37 inches a year. In Santa Rosa, only 12.77 inches of rainfall has fallen this water year, just 3.30 inches more than the driest year of record (1976/1977) when Santa Rosa measured 9.47” through April 15.  On average, Santa Rosa receives 32.20” inches a year.
7. Reservoir capacities are lower than they were during the last drought, which was 2013/2014. View more data on this drought.  
8. Residents are encouraged to continue using water wisely and eliminate water wasting activities. Learn more water saving tips at savingwaterpartnership.org.
9. View more information about the current dry weather conditions.
   
   
10. Read frequently asked questions about the drought.
     

    What is Sonoma Water doing to prepare for a drought?

    • Sonoma Water on December 23, 2021 was awarded close to $9 million from the California Department of Water Resources to make our water supply system more resilient during this and other droughts.  Specifically, these funds will expand and improve the resiliency of the drinking water supply for over 600,000 people in Sonoma and Marin counties by rehabilitating two currently inactive wells, which will provide approximately 3.7 million gallons of water daily.  The funds will also assist with developing planning efforts in the Russian River watershed to address drought conditions and climate change. Read more about the funding here.
      
      
    • In early 2020, Sonoma Water saved 11,000 acre-feet of water in Lake Mendocino (20% of its water capacity at the time) by implementing a deviation request that allowed the U.S. Army Corps of Engineers to use Forecast Informed Reservoir Operations (FIRO) decision support tools. This was a huge water supply reliability effort and the first of its kind in the nation. The development and implementation of FIRO was a direct result of the last drought we faced in 2013/2014. 
    • In early 2020, due to dry weather conditions, Sonoma Water filed a Temporary Urgency Change Petition to preserve water in Lake Mendocino. This effort is estimated to have saved over 10,000 acre-feet of water in Lake Mendocino through the end of 2020. We also implemented a public service announcement campaign alerting our community of the dry weather conditions and the need to use water wisely.
    • In early 2021, Sonoma Water received approval to reduce water releases again from Lake Mendocino through a Temporary Urgency Change Order approved by the State Water Resources Control Board.  Read the press release here. At this point, Sonoma Water is making the minimum release of water from Lake Mendocino; we are currently releasing 25 cubic-feet-per-second at Lake Mendocino.
    • In early 2021, the Sonoma Marin Saving Water Partnership launched an aggressive public outreach campaign to emphasize the need to save water by highlighting actions customers can take to reduce water use and improve water use efficiency. This is in addition to the Partnership’s year-round conservation campaign efforts. The Partnership’s current regional water use of 107 gallons per capital per day (GPCD) represents a 37 percent reduction in water use, well ahead of the State’s required 20 percent reduction in per capita per day water use by 2020.
    • On May 14, 2021, Sonoma Water filed a new Temporary Urgency Change Petition (TUCP) to preserve water in Lake Sonoma.  Read the press release here.
    • May 18, 2021, Sonoma County Board of Supervisors/Sonoma Water Board of Directors approve $400,000 to implement an emergency Santa Rosa Plain well project.  Read this news article.
    • On June 14, 2021, the State Water Resources Control Board approved the above TUCP to preserve water in Lake Sonoma and ordered Sonoma Water and its contractors to reduce Russian River diversions by 20 percent.  Read the press release here.
    • On October 22, 2021 the State Water Resources Control Board issued an amended order that modified Condition 11 of the original order.  Condition 11 limited Sonoma Water cumulative diversions from July 1 through the end of the order (December 10) to 20% below 2020 diversions over the same period. The amended order suspends this requirement while water rights curtailments in the watershed are not in effect whether by suspension or recission. It also requires Sonoma Water customers that are urban water suppliers to implement the appropriate stage of their respective Water Shortage Contingency Plans, consistent with the Governor’s October 19, 2021 emergency drought proclamation.

• We will continue to coordinate public education efforts through multi-media opportunities, such as radio, print and social media. Educating our residents about current conditions and the need to save water is very important.

Flows in the Russian River

• Upper Russian River:
  • Temporary Urgency Change Order allows minimum instream flows to be 25 cubic-feet-per-second. Had the State Order not been in effect, upper Russian River minimum instream flows would be 75 cfs.
    Future flow conditions will be based on water use demands from the river, projected reservoir conditions and state orders.
• Lower Russian River:
  • Temporary Urgency Change Order allows minimum instream flows to be 35 cfs.  Had the State Order not been in effect, lower Russian River minimum instream flows would be 85cfs. 

Current Water Supply Levels for Lake Pillsbury, Lake Mendocino, and Lake Sonoma

*Note that between March 1 and September 30 in Lake Mendocino, the Water Supply Pool is allowed to encroach into the Flood Control Pool and transitions to a higher operational level for the summer season. The "Target Water Supply Curve" represents the normal daily storage level for each day of the year. The daily storage levels were determined based on reservoir modeling of an average year under “Normal” water supply conditions as designated by the Russian River System hydrologic index. Categories of water supply conditions are based on criteria defined in the State Water Resources Control Board Decision 1610. These conditions establish the applicable instream flow requirements.

About Lake Sonoma and Lake Mendocino

Sonoma Water is the local cost-sharing partner for Lake Mendocino and Lake Sonoma, and determines the amount of water to be released from each reservoir when the lake levels are in the water supply pools. The U.S. Army Corps of Engineers determines the amount of water to be released when the lake levels are above the water supply pools and in the flood control pools.

Lake Mendocino relies on year-to-year rainfall to fill as well as water diverted from the Potter Valley Project. Lake Mendocino is a key drinking water source for the cities of Ukiah, Healdsburg, Cloverdale and Hopland, and also provides water to Sonoma Water’s Russian River water supply system. Water releases from Lake Mendocino support flows in the Russian River for the threatened Chinook salmon and steelhead trout during the fall and winter seasons. 

Lake Sonoma is about four times larger than Lake Mendocino and can provide multiple years of water supply. Lake Sonoma relies on rainfall to fill and supports a dynamic and fragile ecosystem in Dry Creek that includes the endangered coho salmon and threatened steelhead trout. Lake Sonoma provides a majority of Sonoma Water's service area with its drinking water.

The Russian River is a managed river system with reservoir releases controlling river flows, especially throughout most of the summer and fall. When tributary stream flows are low, Sonoma Water releases water stored in the reservoirs to supplement the natural flows in the Russian River to provide adequate flows for water supply, recreation and aquatic habitat. A release from a reservoir can be categorized as being of ‘pass-through water’ or ‘stored water’. The term ‘project water’ is often used instead of stored water and is used to describe water that is present because of the dam and reservoir project. Pass-through water is water flowing into the reservoir that is not stored in, but passes through, the reservoir. Project water releases to supplement the natural flows in the Russian River and Dry Creek are necessary to meet mandatory minimum streamflow requirements that exist for both of these watercourses.