Lake J.B. Thomas: 23.0% full as of 2026-08-11
Historical Data
| Date | Percent Full |
Mean Water Level (ft) |
Reservoir Storage (acre-ft) |
Conservation Storage (acre-ft) |
Conservation Capacity (acre-ft) |
Surface Area (acres) |
|
|---|---|---|---|---|---|---|---|
| Today | 2026-08-11 | 23.0 | 2,227.93 | 46,593 | 45,920 | 199,931 | 3,268 |
| Yesterday | 2026-08-10 | 23.0 | 2,227.97 | 46,723 | 46,050 | 199,931 | 3,272 |
| 2 days ago | 2026-08-09 | 23.1 | 2,228.01 | 46,854 | 46,181 | 199,931 | 3,275 |
| 1 week ago | 2026-08-04 | 23.5 | 2,228.23 | 47,577 | 46,904 | 199,931 | 3,296 |
| 1 month ago | 2026-07-11 | 23.4 | 2,228.19 | 47,445 | 46,772 | 199,931 | 3,292 |
| 3 months ago | 2026-05-11 | 25.8 | 2,229.60 | 52,193 | 51,520 | 199,931 | 3,445 |
| 6 months ago | 2026-02-11 | 29.2 | 2,231.53 | 59,066 | 58,393 | 199,931 | 3,686 |
| 1 year ago | 2025-08-11 | 36.7 | 2,235.33 | 74,020 | 73,347 | 199,931 | 4,175 |
*
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 | 2026-08-11 16:45 | 2,227.91 | 2,258.00 | -30.09 |
| 1 hour prior | 2026-08-11 15:45 | 2,227.90 | 2,258.00 | -30.10 |
| 2 hours prior | 2026-08-11 14:45 | 2,227.92 | 2,258.00 | -30.08 |
| 6 hours prior | 2026-08-11 10:45 | 2,227.93 | 2,258.00 | -30.07 |
| 12 hours prior | 2026-08-11 04:45 | 2,227.93 | 2,258.00 | -30.07 |
| 24 hours prior | 2026-08-10 16:45 | 2,227.98 | 2,258.00 | -30.02 |
| 48 hours prior | 2026-08-09 16:45 | 2,228.01 | 2,258.00 | -29.99 |
*
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
