Somerville Lake: 99.5% full as of 2025-08-17

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 2025-08-17 99.5 237.93 149,505 149,505 150,293 11,272
Yesterday 2025-08-16 99.6 237.94 149,617 149,617 150,293 11,290
2 days ago 2025-08-15 99.7 237.96 149,842 149,842 150,293 11,325
1 week ago 2025-08-10 100.0 238.06 150,969 150,293 150,293 - n.a. -
1 month ago 2025-07-17 100.0 238.73 158,642 150,293 150,293 - n.a. -
3 months ago 2025-05-17 100.0 238.18 152,326 150,293 150,293 - n.a. -
6 months ago 2025-02-17 85.7 236.01 128,775 128,775 150,293 10,439
1 year ago 2024-08-17 100.0 238.58 156,905 150,293 150,293 - n.a. -
*

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 2025-08-17 09:00 237.92 238.00 -0.08 below flood pool
1 hour prior 2025-08-17 08:00 237.92 238.00 -0.08 below flood pool
2 hours prior 2025-08-17 07:00 237.92 238.00 -0.08 below flood pool
6 hours prior 2025-08-17 03:00 237.94 238.00 -0.06 below flood pool
12 hours prior 2025-08-16 21:00 237.93 238.00 -0.07 below flood pool
24 hours prior 2025-08-16 09:00 237.94 238.00 -0.06 below flood pool
48 hours prior 2025-08-15 09:00 237.97 238.00 -0.03 below flood pool
*

Data is provisional and subject to revision.

Additional Information

Impoundment date 1967-01-01
Vertical datum NGVD29
Dead pool elevation 206.00 ft above NGVD29
Emergency spillway crest elevation 258.00 ft above NGVD29
Flood pool elevation 258.00 ft above NGVD29
Maximum design elevation 274.50 ft above NGVD29
Top of dam elevation 280.00 ft above NGVD29
Conservation pool elevation 238.00 ft above NGVD29
Data download (CSV) period of record, last one year, last 30 days

Elevation-Area-Capacity Curves

1967-01-01 (source: USGS)
2003-07-01 (source: TWDB) : GIS Data
2012-04-01 (source: TWDB) : GIS Data
Data Source USGS:08109900

Lake Location