Lake Alan Henry: 81.1% full as of 2026-05-01

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 2026-05-01 81.1 2,212.89 78,057 78,057 96,207 2,333
Yesterday 2026-04-30 81.2 2,212.91 78,103 78,103 96,207 2,334
2 days ago 2026-04-29 81.3 2,212.94 78,174 78,174 96,207 2,335
1 week ago 2026-04-24 81.7 2,213.14 78,642 78,642 96,207 2,345
1 month ago 2026-04-01 82.8 2,213.59 79,701 79,701 96,207 2,366
3 months ago 2026-02-01 84.9 2,214.43 81,706 81,706 96,207 2,408
6 months ago 2025-11-01 89.4 2,216.19 86,051 86,051 96,207 2,531
1 year ago 2025-05-01 96.5 2,218.77 92,816 92,816 96,207 2,713
*

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 2026-05-01 06:30 2,212.89 2,220.00 -7.11
1 hour prior 2026-05-01 05:30 2,212.88 2,220.00 -7.12
2 hours prior 2026-05-01 04:30 2,212.89 2,220.00 -7.11
6 hours prior 2026-05-01 00:30 2,212.89 2,220.00 -7.11
12 hours prior 2026-04-30 18:30 2,212.90 2,220.00 -7.10
24 hours prior 2026-04-30 06:30 2,212.92 2,220.00 -7.08
48 hours prior 2026-04-29 06:30 2,212.94 2,220.00 -7.06
*

Data is provisional and subject to revision.

Additional Information

Impoundment date 1994-01-01
Vertical datum NGVD29
Service spillway crest elevation 2,220.00 ft above NGVD29
Emergency spillway crest elevation 2,240.00 ft above NGVD29
Maximum design elevation 2,245.00 ft above NGVD29
Top of dam elevation 2,263.00 ft above NGVD29
Conservation pool elevation 2,220.00 ft above NGVD29
Data download (CSV) period of record, last one year, last 30 days

Elevation-Area-Capacity Curves

1993-10-01 (source: USGS)
2005-07-01 (source: TWDB) : GIS Data
2017-08-01 (source: TWDB) : GIS Data
Data Source USGS:08079700

Lake Location