Lake J.B. Thomas: 23.3% full as of 2026-08-06
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 | 2026-08-06 | 23.3 | 2,228.15 | 47,314 | 46,641 | 199,931 | 3,288 |
| Yesterday | 2026-08-05 | 23.4 | 2,228.18 | 47,413 | 46,740 | 199,931 | 3,291 |
| 2 days ago | 2026-08-04 | 23.5 | 2,228.23 | 47,577 | 46,904 | 199,931 | 3,296 |
| 1 week ago | 2026-07-30 | 23.8 | 2,228.45 | 48,305 | 47,632 | 199,931 | 3,319 |
| 1 month ago | 2026-07-06 | 23.7 | 2,228.38 | 48,073 | 47,400 | 199,931 | 3,312 |
| 3 months ago | 2026-05-06 | 25.9 | 2,229.69 | 52,503 | 51,830 | 199,931 | 3,455 |
| 6 months ago | 2026-02-06 | 29.3 | 2,231.57 | 59,214 | 58,541 | 199,931 | 3,691 |
| 1 year ago | 2025-08-06 | 37.1 | 2,235.53 | 74,857 | 74,184 | 199,931 | 4,196 |
*
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 | 2026-08-06 15:45 | 2,228.14 | 2,258.00 | -29.86 |
| 1 hour prior | 2026-08-06 14:45 | 2,228.15 | 2,258.00 | -29.85 |
| 2 hours prior | 2026-08-06 13:45 | 2,228.15 | 2,258.00 | -29.85 |
| 6 hours prior | 2026-08-06 09:45 | 2,228.14 | 2,258.00 | -29.86 |
| 12 hours prior | 2026-08-06 03:45 | 2,228.15 | 2,258.00 | -29.85 |
| 24 hours prior | 2026-08-05 15:45 | 2,228.18 | 2,258.00 | -29.82 |
| 48 hours prior | 2026-08-04 15:45 | 2,228.23 | 2,258.00 | -29.77 |
*
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
