About Potholes Reservoir
Active alerts and advisories
Conditions that may affect safety or access. Always verify with official sources before heading out.
Lake-specific pages: Weather · Lake level.
Conditions that may affect safety or access. Always verify with official sources before heading out.
Lake-specific pages: Weather · Lake level.
1,028.99 ft
RisingPatchy Blowing Dust · 64.8 mph WNW
Good
Best window: 5:35 AM–6:35 AM
Level 9 days ago · Weather 41 minutes ago · OTHELLO
Potholes Reservoir is managed by U.S. Bureau of Reclamation (Columbia Basin Project, O'Sullivan Dam). Lake Insights displays its latest available elevation from USBR (Columbia Basin Project, O'Sullivan Dam). Published reference elevations are listed below.
Latest gauge observation is older than 72 hours. Figures below are the last available reading, not a confirmed current status.
18.01 feet below full pool
−18.01 ft vs full pool
Potholes Reservoir was 18.01 feet below full pool and has risen slightly over the past week. Recent conditions indicate improving reservoir levels, although the lake remained below its normal operating elevation.
Grant County, WA · U.S. Drought Monitor county statistics at the lake location (not a lake-specific designation)
Moderate Drought
The largest share of Grant County, WA is in Moderate Drought (D1), an official USDM drought category. These figures describe the surrounding county from the lake location, not the lake itself.
Severity
Weekly trend
Stable
Compared with last week
Official drought (D1–D4)
Yes
100% of the surrounding county is in official drought categories (D1–D4). Dominant category remains Moderate Drought.
Typical county impacts (USDM guidance)
U.S. Drought Monitor · map date Oct 6, 2026. Updated weekly. Official drought means U.S. Drought Monitor categories D1–D4 (Moderate through Exceptional). Abnormally Dry (D0) is not counted as official drought. droughtmonitor.unl.eduView drought map for Grant County, WA
Managing authority
Waterbody / project type
Official purposes
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.
Published reference elevation. Not necessarily a fixed year-round target for every project.
Managing authority: U.S. Bureau of Reclamation (Columbia Basin Project, O'Sullivan Dam)
Observation source used by Lake Insights: USBR (Columbia Basin Project, O'Sullivan Dam)
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.
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 USBR (Columbia Basin Project, O'Sullivan Dam), 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.
Full pool
Datum
Current-level source
Project / NID identifier
Dam / watershed (NID inventory record)
Dated National Inventory of Dams fields from a confidently matched record — design values and inventory dates, not live gage readings and not a current inspection or safety determination. An older or missing inspection date does not mean the dam is currently unsafe.
Last inspection date: Aug 18, 2023
Inventory record values only. Dates shown are what NID published for this dam entry — not a Lake Insights inspection or an up-to-date safety rating.
National Inventory of Dams · matched record: O'sullivan Dam (WA00268) · last inspection date on record Aug 18, 2023
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.