Lake J.B. Thomas: 44.5% full as of 2021-09-25

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 2021-09-25 44.5 2,238.89 89,614 88,941 199,931 4,601
Yesterday 2021-09-24 44.5 2,238.91 89,706 89,033 199,931 4,603
2 days ago 2021-09-23 44.6 2,238.94 89,844 89,171 199,931 4,607
1 week ago 2021-09-18 45.0 2,239.12 90,676 90,003 199,931 4,630
1 month ago 2021-08-25 46.6 2,239.79 93,808 93,135 199,931 4,719
3 months ago 2021-06-25 22.3 2,227.53 45,293 44,620 199,931 3,233
6 months ago 2021-03-25 12.5 2,220.67 25,677 25,004 199,931 2,417
1 year ago 2020-09-25 17.7 2,224.51 35,961 35,288 199,931 2,933
*

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 2021-09-25 05:45 2,238.88 2,258.00 -19.12 below flood pool
1 hour prior 2021-09-25 04:45 2,238.89 2,258.00 -19.11 below flood pool
2 hours prior 2021-09-25 03:45 2,238.89 2,258.00 -19.11 below flood pool
6 hours prior 2021-09-24 23:45 2,238.89 2,258.00 -19.11 below flood pool
12 hours prior 2021-09-24 17:45 2,238.91 2,258.00 -19.09 below flood pool
24 hours prior 2021-09-24 05:45 2,238.91 2,258.00 -19.09 below flood pool
48 hours prior 2021-09-23 05:45 2,238.95 2,258.00 -19.05 below flood pool
*

Data is provisional and subject to revision.

Additional Information

Impoundment date 1952-01-01
Vertical datum NGVD29
Gauge USGS:08118000
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

Lake Location