Lake J.B. Thomas: 20.5% full as of 2026-10-24
Historical Data
| Date | Percent Full |
Mean Water Level (ft) |
Reservoir Storage (acre-ft) |
Conservation Storage (acre-ft) |
Conservation Capacity (acre-ft) |
Surface Area (acres) |
|
|---|---|---|---|---|---|---|---|
| Most recent | 2026-10-24 | 20.5 | 2,226.36 | 41,570 | 40,897 | 199,931 | 3,128 |
| 1 day prior | 2026-10-23 | 20.5 | 2,226.37 | 41,602 | 40,929 | 199,931 | 3,129 |
| 2 days prior | 2026-10-22 | 20.5 | 2,226.40 | 41,695 | 41,022 | 199,931 | 3,132 |
| 1 week prior | 2026-10-17 | 20.4 | 2,226.32 | 41,446 | 40,773 | 199,931 | 3,125 |
| 1 month prior | 2026-09-24 | 20.2 | 2,226.22 | 41,133 | 40,460 | 199,931 | 3,115 |
| 3 months prior | 2026-07-24 | 24.2 | 2,228.70 | 49,138 | 48,465 | 199,931 | 3,345 |
| 6 months prior | 2026-04-24 | 26.5 | 2,230.00 | 53,580 | 52,907 | 199,931 | 3,491 |
| 1 year prior | 2025-10-24 | 33.0 | 2,233.51 | 66,624 | 65,951 | 199,931 | 3,944 |
*
Percent Full is based on Conservation Storage and Conservation Capacity and doesn't account for storage in flood pool.
**
Values above, including today's are averaged conditions. For near real-time instantaneous water level, see table below or the interactive map viewer.
Most Recent Instantaneous Water Level
| Date/time |
Water Level (ft) |
Conservation Pool Elevation (ft) |
Height Above Conservation Pool (ft) |
|
|---|---|---|---|---|
| Most recent | 2026-10-24 23:45 | 2,226.35 | 2,258.00 | -31.65 |
| 1 hour prior | 2026-10-24 22:45 | 2,226.35 | 2,258.00 | -31.65 |
| 2 hours prior | 2026-10-24 21:45 | 2,226.35 | 2,258.00 | -31.65 |
| 6 hours prior | 2026-10-24 17:45 | 2,226.35 | 2,258.00 | -31.65 |
| 12 hours prior | 2026-10-24 11:45 | 2,226.36 | 2,258.00 | -31.64 |
| 24 hours prior | 2026-10-23 23:45 | 2,226.36 | 2,258.00 | -31.64 |
| 48 hours prior | 2026-10-22 23:45 | 2,226.38 | 2,258.00 | -31.62 |
*
Data is provisional and subject to revision.
Additional Information
| Impoundment date | 1952-01-01 |
| Vertical datum | NGVD29 |
| Dead pool elevation | 2,200.00 ft above NGVD29 |
| Service spillway crest elevation | 2,258.00 ft above NGVD29 |
| Emergency spillway crest elevation | 2,264.00 ft above NGVD29 |
| Emergency spillway crest elevation | 2,267.00 ft above NGVD29 |
| Maximum design elevation | 2,275.00 ft above NGVD29 |
| Top of dam elevation | 2,280.00 ft above NGVD29 |
| Conservation pool elevation | 2,258.00 ft above NGVD29 |
| Data download (CSV) | period of record, last one year, last 30 days |
| Data Source | USGS:08118000 |
| USGS Monitoring Location | USGS:08118000 |
Lake Location
