Lake J.B. Thomas: 19.6% full as of 2026-10-06
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 | 2026-10-06 | 19.6 | 2,225.80 | 39,834 | 39,161 | 199,931 | 3,072 |
| Yesterday | 2026-10-05 | 19.6 | 2,225.82 | 39,896 | 39,223 | 199,931 | 3,074 |
| 2 days ago | 2026-10-04 | 19.7 | 2,225.85 | 39,988 | 39,315 | 199,931 | 3,077 |
| 1 week ago | 2026-09-29 | 20.0 | 2,226.05 | 40,606 | 39,933 | 199,931 | 3,098 |
| 1 month ago | 2026-09-06 | 21.2 | 2,226.83 | 43,051 | 42,378 | 199,931 | 3,172 |
| 3 months ago | 2026-07-06 | 23.7 | 2,228.38 | 48,073 | 47,400 | 199,931 | 3,312 |
| 6 months ago | 2026-04-06 | 27.1 | 2,230.38 | 54,915 | 54,242 | 199,931 | 3,538 |
| 1 year ago | 2025-10-06 | 33.7 | 2,233.87 | 68,052 | 67,379 | 199,931 | 3,995 |
*
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 | 2026-10-06 16:45 | 2,225.80 | 2,258.00 | -32.20 |
| 1 hour prior | 2026-10-06 15:45 | 2,225.80 | 2,258.00 | -32.20 |
| 2 hours prior | 2026-10-06 14:45 | 2,225.80 | 2,258.00 | -32.20 |
| 6 hours prior | 2026-10-06 10:45 | 2,225.80 | 2,258.00 | -32.20 |
| 12 hours prior | 2026-10-06 04:45 | 2,225.80 | 2,258.00 | -32.20 |
| 24 hours prior | 2026-10-05 16:45 | 2,225.82 | 2,258.00 | -32.18 |
| 48 hours prior | 2026-10-04 16:45 | 2,225.85 | 2,258.00 | -32.15 |
*
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
