Where the lake levels come from
Every number on this site is a reading published by the agency that operates the lake or its gauge. We do not model, estimate or forecast levels. A script checks each source every few hours, stores the daily readings, and the site is rebuilt only when a level changes.
Sources
| Agency | Feed | Lakes |
|---|---|---|
| Texas Water Development Board | Water Data for Texas: daily elevation, storage and percent full | 45 |
| U.S. Army Corps of Engineers | CWMS Data API: hourly pool elevation and, where published, the guide curve | 28 |
| U.S. Geological Survey | Water Services: lake and reservoir elevation gauges | 11 |
| California Department of Water Resources | CDEC: daily reservoir elevation and storage | 10 |
| U.S. Bureau of Reclamation | Hydrologic Database (HDB): daily end-of-day elevation | 6 |
What the numbers mean
Level / elevation is the water surface height in feet above sea level at the dam or gauge, in the datum the agency uses. It is not water depth.
Full pool is the top of the conservation pool: the normal maximum level used for water supply and recreation. Water above it is flood storage that the operator releases when it can. In Texas, percent full is TWDB's conservation storage divided by conservation capacity.
Guide curve is the seasonal target level the Corps of Engineers aims for at some lakes (usually higher in summer, lower in winter).
Daily values: for each day we keep the last reading of that local day. Changes ("past 7 days", "vs 1 year ago") compare today's reading with the reading on that earlier date.
Accuracy
Recent readings are provisional: agencies sometimes correct them later, and a gauge can go offline. If a lake has no new reading for more than ten days, we take its page down until data returns. Do not use this site for navigation, flood or dam safety decisions; follow the operating agency and the National Weather Service.