Where Our Data Comes From
Every number on this site comes from a public agency. This is what each one covers.
| Source | Covers | Frequency | License | Lakes |
|---|---|---|---|---|
| Texas Water Development Board (Water Data for Texas) | Texas reservoirs: level, storage, percent full | Daily average | Public data, with TWDB disclaimer | 73 |
| US Geological Survey (USGS) | Reservoir gauges nationwide | Every 15 min, provisional | Public domain | 3 |
| US Army Corps of Engineers (CWMS) | Corps reservoirs: pool elevation | Hourly, provisional | Public domain | 51 |
| National Weather Service gauges (NWPS) | TVA and Duke Energy lakes and Lake Pleasant, as reported to the NWS | Hourly, provisional | Public domain | 10 |
| Iowa Environmental Mesonet (Iowa State University) | Archive of past NWS gauge reports, used for history | Daily archive | Free use with attribution | 10 |
| Bureau of Reclamation (RISE) | Lake Mead and the history of Lake Powell | Daily | Public domain | 1 |
| NOAA CO-OPS | Great Lakes levels at shore gauges and water temperature | Every 6 min | Public domain | 5 |
| NOAA GLERL | Great Lakes lake-wide averages since 1918 and satellite water temperature (GLSEA) | Daily | Public domain | 5 |
| National Weather Service | Weather forecast and wind at each lake | Hourly | Public domain | All |
| National Inventory of Dams (USACE) | Dam name, river, owner, year completed | Yearly | Public domain | All |
Provisional data
Readings from the last months at USGS and Corps of Engineers gauges have not been reviewed yet. The agency can correct them later, for example after cleaning a sensor or adjusting for its drift. Pages with this kind of data say “Provisional data” next to the number.
Update schedule
The site checks every source several times a day. Texas readings change once a day, when TWDB publishes the daily average; hourly gauges show their newest reading at each check. The time of the reading is on every page.
Maps
State outlines from the US Census Bureau via the us-atlas project. Lake positions are the gauge locations published by each source.
Where this data comes from
Lake Levels Daily keeps a copy of each reading to build the history and charts. It does not change the values it receives.
Lake Levels Daily is an independent site, not affiliated with TWDB, LCRA, USACE, USGS, NOAA, TVA or any lake operator. Check official sources before making safety decisions.