Lake J.B. Thomas: 23.5% full as of 2026-08-04
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 | 2026-08-04 | 23.5 | 2,228.24 | 47,610 | 46,937 | 199,931 | 3,297 |
| Yesterday | 2026-08-03 | 23.5 | 2,228.28 | 47,742 | 47,069 | 199,931 | 3,302 |
| 2 days ago | 2026-08-02 | 23.6 | 2,228.32 | 47,874 | 47,201 | 199,931 | 3,306 |
| 1 week ago | 2026-07-28 | 24.0 | 2,228.54 | 48,604 | 47,931 | 199,931 | 3,329 |
| 1 month ago | 2026-07-04 | 23.7 | 2,228.40 | 48,139 | 47,466 | 199,931 | 3,314 |
| 3 months ago | 2026-05-04 | 26.1 | 2,229.77 | 52,780 | 52,107 | 199,931 | 3,464 |
| 6 months ago | 2026-02-04 | 29.3 | 2,231.60 | 59,325 | 58,652 | 199,931 | 3,695 |
| 1 year ago | 2025-08-04 | 37.3 | 2,235.60 | 75,152 | 74,479 | 199,931 | 4,203 |
*
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 | 2026-08-04 15:45 | 2,228.23 | 2,258.00 | -29.77 |
| 1 hour prior | 2026-08-04 14:45 | 2,228.21 | 2,258.00 | -29.79 |
| 2 hours prior | 2026-08-04 13:45 | 2,228.24 | 2,258.00 | -29.76 |
| 6 hours prior | 2026-08-04 09:45 | 2,228.24 | 2,258.00 | -29.76 |
| 12 hours prior | 2026-08-04 03:45 | 2,228.24 | 2,258.00 | -29.76 |
| 24 hours prior | 2026-08-03 15:45 | 2,228.27 | 2,258.00 | -29.73 |
| 48 hours prior | 2026-08-02 15:45 | 2,228.32 | 2,258.00 | -29.68 |
*
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
