Lake Sonoma
Lake Sonoma is managed by U.S. Army Corps of Engineers — San Francisco District. Lake Insights displays its latest available elevation from USACE SPN District. Published reference elevations are listed below.
Lake Status
2.96 feet below full pool
−2.96 ft vs full pool
- 7-day trend
- Falling
- 7-day change
- Down 0.26 ft
- 30-day change
- Down 0.26 ft
- Last updated
- 2 hours ago
Lake Sonoma is currently 2.96 feet below full pool and has fallen slightly over the past week. Readings show continued drawdown relative to full pool, with levels trending lower over the past week.
Watershed drought conditions
Sonoma County, CA · surrounding county from lake location
No Drought
No official drought conditions.
Severity
Weekly trend
Stable
Compared with last week
Official drought
No
No official drought is reported for the surrounding watershed.
U.S. Drought Monitor · map date Sep 8, 2026. Updated weekly. droughtmonitor.unl.eduView drought map for Sonoma County, CA
Key Facts
Managing authority
Waterbody / project type
Official purposes
Full pool
Datum
Current-level source
Project / NID identifier
Dam / watershed (NID design values)
Static design values from a confidently matched National Inventory of Dams record — not live gage readings.
- Max storage
- 240 acre-ft
- Surface area at normal pool
- 29 acres
- Drainage area
- 1.3 sq mi
- Dam structure
- Earth · 38 ft high · completed 1991
- Hazard classification
- Low
- Safety & inspection
- Satisfactory · last inspection Apr 23, 2025
National Inventory of Dams · matched record: Sonoma Hills (CA01321)
How this lake is operated
- Documented project purposes (National Inventory of Dams): Water Supply, Irrigation, Recreation.
Why the level can change
General factors for reservoirs like this
These are common influences for this type of lake. They do not identify the cause of a specific current change unless an operator update confirms it.
Rainfall & inflows
Rain and upstream river inflows can raise reservoir levels, especially after storms.
Downstream releases
When an operator releases water through a dam, reservoir storage can fall and downstream flows can rise.
Flood-risk operations
Some projects store or release water under flood-risk rules when conditions require it.
Water supply
Some reservoirs support municipal, industrial, irrigation, or regional water-supply needs.
Hydropower
Hydropower projects may pass water through turbines when generating electricity.
Seasonal weather
Dry periods, heat, evaporation, and seasonal rainfall patterns can affect storage over weeks and months.
Published reference elevations
- Full pool
- 451.00 ft
Published reference elevation. Not necessarily a fixed year-round target for every project.
Current data source
Managing authority: U.S. Army Corps of Engineers — San Francisco District
Observation source used by Lake Insights: USACE SPN District
Who manages the lake and who publishes the reading Lake Insights displays can differ. Lake Insights does not invent a source label from the managing authority alone.
General education
Shared background — not lake-specific facts
Lake Insights aggregates water level information from authoritative public sources such as the U.S. Army Corps of Engineers, NOAA, TVA, Bureau of Reclamation, power utilities, and other official lake operators. We preserve historical observations, calculate trends, and present lake conditions in a consistent format. For USACE SPN District, we link to the official source whenever it is available. Lake Insights does not predict future lake levels unless an official forecast has been published by the managing authority.
Common questions about Lake Sonoma
- Who manages Lake Sonoma?
- Lake Sonoma is managed by U.S. Army Corps of Engineers — San Francisco District. Lake Insights reports published gauge readings; it does not operate the waterbody.
- What is full pool at Lake Sonoma?
- The published full-pool elevation for Lake Sonoma is 451.00 ft (NGVD29). Full pool is a published reference elevation — not a prediction of today’s level.
- Where does Lake Insights get the level reading for Lake Sonoma?
- Lake Insights displays the latest available elevation for Lake Sonoma from USACE SPN District. The managing authority (U.S. Army Corps of Engineers — San Francisco District) may differ from the agency that publishes the observation used on this page.
- What datum is used for Lake Sonoma?
- Elevations for Lake Sonoma are referenced to NGVD29 (MSL).
- What are the documented purposes of Lake Sonoma?
- Documented purposes for Lake Sonoma (National Inventory of Dams): Water Supply, Irrigation, Recreation.