Lake J.B. Thomas: 19.5% full as of 2026-10-09
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 | 2026-10-09 | 19.5 | 2,225.72 | 39,589 | 38,916 | 199,931 | 3,063 |
| Yesterday | 2026-10-08 | 19.5 | 2,225.74 | 39,650 | 38,977 | 199,931 | 3,065 |
| 2 days ago | 2026-10-07 | 19.5 | 2,225.77 | 39,742 | 39,069 | 199,931 | 3,068 |
| 1 week ago | 2026-10-02 | 19.8 | 2,225.92 | 40,203 | 39,530 | 199,931 | 3,085 |
| 1 month ago | 2026-09-09 | 21.0 | 2,226.71 | 42,671 | 41,998 | 199,931 | 3,161 |
| 3 months ago | 2026-07-09 | 23.5 | 2,228.28 | 47,742 | 47,069 | 199,931 | 3,302 |
| 6 months ago | 2026-04-09 | 27.0 | 2,230.30 | 54,633 | 53,960 | 199,931 | 3,528 |
| 1 year ago | 2025-10-09 | 33.5 | 2,233.78 | 67,694 | 67,021 | 199,931 | 3,982 |
*
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 | 2026-10-09 05:45 | 2,225.72 | 2,258.00 | -32.28 |
| 1 hour prior | 2026-10-09 04:45 | 2,225.71 | 2,258.00 | -32.29 |
| 2 hours prior | 2026-10-09 03:45 | 2,225.71 | 2,258.00 | -32.29 |
| 6 hours prior | 2026-10-08 23:45 | 2,225.72 | 2,258.00 | -32.28 |
| 12 hours prior | 2026-10-08 17:45 | 2,225.74 | 2,258.00 | -32.26 |
| 24 hours prior | 2026-10-08 05:45 | 2,225.75 | 2,258.00 | -32.25 |
| 48 hours prior | 2026-10-07 05:45 | 2,225.78 | 2,258.00 | -32.22 |
*
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
