Lake J.B. Thomas: 42.4% full as of 2024-12-30

The elevation-storage rating curve used to produce the storage hydrograph is made of two segments: (1) the segment up to the conservation pool top (below the red line) is based on measured data, and (2) the segment in the flood pool (above the red line) is an extrapolation from the first segment and shouldn't be relied upon for flood storage information.

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 2024-12-30 42.4 2,237.97 85,434 84,761 199,931 4,484
Yesterday 2024-12-29 42.4 2,237.98 85,479 84,806 199,931 4,485
2 days ago 2024-12-28 42.5 2,238.00 85,569 84,896 199,931 4,488
1 week ago 2024-12-23 42.6 2,238.05 85,794 85,121 199,931 4,495
1 month ago 2024-11-30 43.3 2,238.37 87,238 86,565 199,931 4,536
3 months ago 2024-09-30 37.8 2,235.88 76,332 75,659 199,931 4,233
6 months ago 2024-06-30 19.5 2,225.72 39,589 38,916 199,931 3,063
1 year ago 2023-12-30 22.1 2,227.38 44,808 44,135 199,931 3,220
*

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 2024-12-30 07:45 2,237.99 2,258.00 -20.01
1 hour prior 2024-12-30 06:45 2,237.96 2,258.00 -20.04
2 hours prior 2024-12-30 05:45 2,237.96 2,258.00 -20.04
6 hours prior 2024-12-30 01:45 2,237.96 2,258.00 -20.04
12 hours prior 2024-12-29 19:45 2,237.97 2,258.00 -20.03
24 hours prior 2024-12-29 07:45 2,237.98 2,258.00 -20.02
48 hours prior 2024-12-28 07:45 2,238.00 2,258.00 -20.00
*

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

Elevation-Area-Capacity Curves

1952-01-01 (source: USGS)
1999-11-01 (source: TWDB) : GIS Data
Data Source USGS:08118000

Lake Location