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July 21, 2011
Drought Impacts on Texas Reservoirs Mounting
ATHENS—Following the drought of record of the 1950s, Texas built dozens of reservoirs designed to maintain an adequate water supply should another drought of equal severity occur.
That time has come, and the coming months will reveal if those reservoirs are equal to the task.
The outcome is anything but certain. As shown by the thunderstorms that swept across extreme North Texas in early summer and boosted water levels in lakes around Dallas-Fort Worth, one exceptional rain event can go far toward relieving an exceptional drought, at least in the short term.
But we can’t control the weather, and only one other part of the state has been blessed with reservoir-filling rains since the drought began in earnest in 2010. “Heavy rainfall in the Rio Grande watershed in 2010 filled both Amistad and Falcon International Reservoirs,” said Texas Parks and Wildlife Department (TPWD) Inland Fisheries biologists Randy Myers. “Amistad is currently two to three feet below conservation pool, and Falcon is about 15 feet low. Angler access remains excellent at both. With the current drought, water levels in both reservoirs should decrease but not reach problematic levels this year.”
Everywhere else across the state, TPWD fisheries managers are dealing with what appears to have the potential to become the new drought of record. [For current information on drought status, visit the Texas Water Development Board’s web site.]
“Some Hill Country lakes have been severely affected by the drought,” said TPWD biologist Marcos De Jesus. “Lakes Travis, Buchanan and Canyon are nearing record lows. The biggest problem in this area is access as lake levels fall below the point where boat ramps are usable.” [The TPWD web site provides links to reservoir controlling authority web sites providing water level and access information for individual reservoirs.]
De Jesus suggests anglers consider switching to lakes with more stable water levels, such as Inks, LBJ, Austin, Lady Bird, Fayette, Bastrop and Walter E. Long. “All of these reservoirs provide excellent, diverse fishing opportunities with easy access,” he said.
Conditions are similar at Choke Canyon, Coleto Creek, Texana and Lake Corpus Christi, said TPWD biologist John Findeisen. “As water level decreases we lose habitat, and this concentrates the fish to the remaining available habitat and provides ample successful fishing trips,” he said. “Fishing reports from Choke Canyon, Coleto Creek and Lake Corpus Christi are good, with lots of bass and catfish being caught. Access is not a problem at this time, but anglers need to be aware of timber now at or just below the surface.”
West Texas and Panhandle lakes have been hit particularly hard by the drought. Lakes Baylor (near Childress) and O.C. Fisher (San Angelo) have dried up. “Lake Meredith is listed at zero percent capacity, though it still covers about 2,000 acres,” said TPWD biologist Charlie Munger. “Low water levels have concentrated the fish, so walleye fishing was very good this year. Unfortunately, golden alga has impacted the catfish fishery.
“Lake Alan Henry is the one bright spot in the High Plains, as it is about 86 percent full,” Munger continued. “A pipeline to Lubbock now under construction will be completed in 2012 and will greatly impact water levels, but right now the reservoir is doing well. Largemouth bass anglers reported good catches this spring.”
O. H. Ivie Reservoir, the leader in entries into the Toyota ShareLunker program the last two seasons, is at 24 percent capacity, but anglers are still doing well, according to Jerry Hunter, manager of Elm Creek Village Marina. “Ivie is 33 feet low, but we still have 17 feet of water over the end of our ramp,” Hunter said. “Fishing is pretty slow, which is typical of summertime, but we usually see at least one double-digit fish a week.”
Other Panhandle and West Texas reservoirs range from less than one percent capacity (E.V. Spence, near San Angelo) to 46 percent full (Oak Creek Reservoir, near Sweetwater). “High evaporation rates and abstraction for municipal water supply are taking a toll,” said TPWD fisheries biologist Mukhtar Farooqi. “However, low water levels concentrate prey species that sportfish can take advantage of, and by the same token, sportfish should be easier for anglers to locate. Anglers can also take advantage of low water levels to mark structures using their GPS units and then target these areas when water levels rise.”
Low water levels can actually be beneficial to reservoir fisheries in the long run, as pointed out by several TPWD fisheries biologists. “Long-term benefits come from the establishment of terrestrial vegetation along shorelines that will provide a nutrient boost when lakes fill again,” said De Jesus.
In the short term, lower lake levels do impact fish reproduction, said TPWD fisheries biologist Craig Bonds. “Degraded habitat will likely result in poor reproductive success for many sport and prey fishes,” he said. “However, one poor year class does not pose long-term problems.”
“When the rains do come and reservoir water levels are suitable, TPWD will stock fish to rebuild the fisheries, taking advantage of the new habitat created by flooded terrestrial vegetation that took hold when lake levels were low,” explained Farooqi.
TPWD’s five freshwater fish hatcheries are making plans to be ready to restock reservoirs when levels rise, but they are facing their own set of challenges due to the drought.
“So far hatchery operations have not been impacted,” said Todd Engeling, director of hatchery operations for TPWD. “Our ability to divert water for hatchery production is obviously a key factor in sustaining hatchery operations,” he added. “In general, hatchery operations are considered to be non-consumptive, since 95 percent or more of the water diverted is typically returned. If the drought continues, we will most likely see impacts first at the A.E. Wood Fish Hatchery in San Marcos, where our ability to divert water from the San Marcos River is significantly reduced as flows drop in the river. In most cases our facilities enjoy senior water rights [meaning they are first in line for what water is available], but as lake levels continue to drop, it is likely that we will see additional restrictions on our withdrawals.”
If hatcheries are unable to maintain their water supplies, emphasis will switch from producing fish for stocking to protecting the valuable broodfish that are held on the hatcheries year-around to produce the next generation of fish for stocking. Contingency plans are also being made to transfer broodfish from hatcheries without adequate water to those with better supplies should that become necessary.
A complicating factor is that reduced streamflows can result in increased salinity, making it more likely reservoirs or streams supplying water to some hatcheries will suffer from outbreaks of golden alga, which can kill fish.
Reduced water levels and higher water temperatures in streams and reservoirs also lead to lower levels of dissolved oxygen in water, which can also be fatal to fish. TPWD’s Kills and Spills Team monitors fish kill events and can be notified of fish kills at their 24-hour hotline, (512) 389-4848.
Rainfall in Texas historically follows a boom-and-bust cycle. That’s why the nearly 200 major reservoirs exist in the state, to catch and hold water to sustain us in the dry times between wet times. But since we never know when the next drought will come, how severe it will be and how long it will last, prudence demands making the most of every drop of precious water those reservoirs hold.
Remember that every time you start to turn on a faucet.
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