Friday, May 30, 2014

Rain Results

So, following the healthy rains we recently received, how much have our area reservoirs improved?

First, San Angelo's main water source is lake O.H. Ivie, which is located about 50 or more miles east of Angelo. O.H. Ivie is fed by the Colorado River and the Concho River. Since the three Concho Rivers converge in San Angelo where they become the Concho, that means that much of the water from the Concho that pours into O.H. Ivie comes first through San Angelo.

Map showing area lakes. O.C. Fisher is to the northwest, Lake Nasworthy to the southwest, and Twin Buttes just west of Nasworthy. To the east is the largest of our area lakes, O.H. Ivie.
We also get water from a group of lakes on the western edge of the city: O.C. Fisher, Twin Buttes, and Nasworthy. O.C. Fisher is fed primarily by the North Concho River, although there are some small wet weather creeks that feed runoff into the reservoir. Twin Buttes actually has two "pools." The north pool is fed by the Middle Concho River, Dove Creek, and Spring Creek. The south pool is fed by the South Concho River. The two pools are connected by a channel. Just to the east of the long dam forming Twin Buttes is spider-shaped Lake Naswrothy, which is fed by the Middle Concho and the South Concho Rivers as well as Pecan Creek. Actually, water is released from Twin Buttes into Lake Nasworthy, making this smaller lake a constant level lake except in times of extreme drought, such as we have recently experienced. Normally, Nasworthy hovers about 90% capacity. However, since Twin Buttes recently dried up, it was no longer able to pump water into Nasworthy, and the latter lake's capacity had dropped to about 50%. In fact, just prior to the recent rains, all but 2 of the lake's boat ramps had been closed. Over the years, Nasworthy has made San Angelo the "oasis of West Texas" and has attracted water enthusiasts from all over West Texas and even eastern New Mexico. The drought has certainly been affecting our economics.

From last Friday through Monday nights, I recorded right at 8 inches of rain at my house. Mathis Field, our regional airport located just east of Lake Nasworthy, recorded 7.42 inches during the same period. We had a good few days of rain.

By now, most of the rain has found it's way to the lake where it will end up. Here are the results of our rains. Note the chart shows the level of each lake both before AND after the recent rains so you can see just how significant the increase has been for us. These rains will buy us several months of life.


You can see that Ivie almost doubled both in capacity and acre-feet, and I expect that it will increase just a bit more in the next day or so. The other lakes should not change much. At one point following the rains, Nasworthy was actually at 102% capacity, but water was released down river to Ivie.

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