Spence Reservoir continues gains from floodwater runoff


The reservoir will show gains for the next several days as floodwater from recent rainfall makes its way into its impound basin

FILE PHOTO (April 2015): E.V. Spence Reservoir, Robert Lee, Texas. Photo by Ken Grimm

Heavy rains along the I-20 corridor near Colorado City, Texas produced enough runoff to trigger a flood warning for the Colorado from the National Weather Service this week.

The runoff did cause the river in that area to rise to *just* below flood stage in the early morning hours of June 2, 2021. It reached 14.93′ at 12:15 a.m. that morning, seven one-hundreths of a foot below the 15 foot flood stage.

The Colorado River reached its peak stream height in the early morning hours of Jun 2, 2021

The next measuring station downstream for the river before emptying into the Spence reservoir — located near Silver, Texas — recorded the flow of the flood water as it passed by the next day on June 3, 2021. It reached a stream height level of approximately 9.4′, up from below three feet just 5 days earlier.

The flood waters from the heavy rains passed the river gauge near Silver, Texas on June 3, 2021, heading to the E.V. Spence Reservoir in Robert Lee.

At the time of this report, E.V. Spence is recording significant gains in volume of water impounded. Since May 1, 2021, the reservoir has gained 1.71 feet in vertical height, which translates to an additional 9,600 acre-feet (3.1 billion gallons), gaining 1.84% in percentage full (from 21.54% to 23.37%).

The recorded rise in volume has not tapered off and continues to climb as of today:

Flood waters from the Colorado River continue to pour into the E.V. Spence Reservoir from the recent heavy rains.

Here are the most recent data from the area’s six reservoirs:

Current Concho Valley Reservoir Status

(Note: The Twin Buttes north pool is currently above the 1926.5' elevation, at which point the north and south pools are considered equalized as a single body of water. The conservation acre-feet storage capacity, used in determining the full capacity of the reservoir, is taken from the revised March 2018 tables developed by the United States Department of the Interior, Bureau of Reclamation, Great Plains Region (using 1964 tables plus 1970 USGS Survey data) for the Middle Pool, with an additional 4,602 acre-feet added to account for the additional water in the south pool.)

Reservoir Date Time Elevation
Acre-Feet Gallons Percent
Nasworthy6/5/20216:00 a.m. 1,871.08 8,061 2,626,684,911 83.84%
O.C. Fisher6/5/20216:00 a.m. 1,865.09 6,493 2,115,750,543 5.61%
Oak Creek6/5/20216:00 a.m. 1,995.78 29,965 9,764,125,215 76.42%
Twin Buttes6/5/20216:00 a.m. 1,927.85 98,834 32,205,157,734 53.00%
E.V. Spence6/5/20216:00 a.m. 1,858.46 120,900 39,395,385,900 23.37%
O.H. Ivie6/5/20216:00 a.m. 1,538.05 334,300 108,931,989,300 60.31%
Total 598,553 195,039,093,603 42.21%

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Water Conservation Status

Standard Conservation

San Angelo is in standard conservation, which restricts outside watering to twice every seven days at no more than 1 inch per week, no watering between noon and 6 pm. Runoff of more than 150 feet down any street, gutter, alley or ditch is prohibited.

Report watering violations by clicking on https://www.cosatx.us/departments-services/water-conservation/report-a-water-violation or calling 325-657-4409. Do your part; be water smart!