THE RAIN EFFECT

The big rains that fell across much of Texas last spring and summer brought utter devastation to parts of the landscape and wrecked countless lives as it caused historic flooding that washed out roadways, breached dams and swept away numerous homes and vehicles, killing nearly three dozen people in the process.

The wicked El Niño weather pattern rolled into the state in February and gradually gained steam through May. That’s when it dumped record amounts of rainfall on already soggy ground, causing creeks and rivers to swell well beyond their banks, sending way more water flowing downstream than some major reservoirs could hold.

Dozens of impoundments — some of them drought-stricken for years — refilled in short order, while others were partially recharged with several feet of much-welcomed water. In some cases the water rushed in way faster than controlling authorities could let it out, resulting in extended periods of high water that spurred boat ramp and camp ground closures that lasted for months.

The area around Lake Texoma was particularly hard it. During June, the Texas/Oklahoma border lake rose more than 28 feet above full pool and jumped its emergency spillway twice. Not far to the north, just ahead of Mother’s Day weekend, the dam ruptured on Jimmy Houston’s 125-acre Lake Twin Eagle, sending a staggering number of trophy bass and outsize crappie on a watery path to the Washita River.

Houston was in Alabama practicing for a bass tournament when he got word that his beloved honey hole was gone. “It wasn’t like getting told you’re going to die in three weeks or anything like that, but it was a pretty bad deal,” he said.

As destructive as the Spring 2015 floods were, they came with a silver lining that is sure to benefit many of our lakes and the sport fisheries finning around in them for several years to come. In other words, the long term fishing forecast looks pretty promising.

The reason? It’s all about “trophic upsurge.”

Understanding Trophic Upsurge

As earlier mentioned, water levels on many Texas lakes were well below normal before the rains came. Some had been starving for water for years. 

During extended periods of low water, large expanses of the lake bed normally covered by water are exposed to direct sunlight.

Sunlight spurs the gradual growth of grasses, weeds, bushes, trees and other forms of terrestrial vegetation native to the landscape. The longer the lake remains low, the thicker and more widespread the new growth vegetation becomes.

When water levels rise and all that new growth vegetation is flooded, it pumps in rich nutrients that act as liquid fertilizer to everything in its path. This promotes a boom in plankton growth, benefitting everything from forage fish populations to top end predators like bass, catfish and crappie.

The jungle of flooded cover also provides young-of-the-year game fish and forage such as sunfish and shad good places to hide from predators. This usually results in extremely high recruitment among one or more year classes of fish, ultimately leading to banner fishing several years down the road as the fish mature.

Translation: Trophic upsurge, also known as the “new lake effect,” has the ability to make a tired or old fishery seem new again.

The new lake phenomenon has been documented on a number of Texas reservoirs over the years, and several more are in line for revivals as a result of the big rains that fell across Texas last spring.

To wit:

• Lake Alan Henry saw a 10 1/2 rise and went from 73 percent capacity to full pool.

• Lake Cooper caught 12 feet of water and jumped from 39 percent full to 100 percent full. 

• Lake Amon G. Carter went from 56.1 percent full to six feet high after catching 12 feet of water in a single month.

• Lake Richland Chambers rose from 63 percent capacity to a foot high as the result of an 11 1/2 foot rise.

• Lake Lavon went from 46 percent full to foot high after catching nearly 13 feet of water.

• Lake Ray Hubbard jumped 10 feet from 59 percent capacity to nearly 100 percent full.

• Lake Grapevine rose 28 feet, refilling from 57 percent capacity to 15 feet above normal.

• Lake Bridgeport rose more than 23 feet, from 38.9 percent capacity to 99 percent full.

• Lake Belton jumped nearly 11 feet from 72 percent capacity to nearly a foot high.

• Fort Phantom Hill Reservoir near Abilene rose 15.2 feet and refilled from 31.1 percent to 88.5 percent full.

• Lake Possum Kingdom rose more than 13 feet from 63.9 percent capacity to 98.7 percent.

The list goes on and on. Lakes Fork, Cedar Creek, Stillhouse Hollow, Falcon, Canyon, Benbook, Georgetown, Travis, Buchanan, Granbury, and a host of others saw significant rises last spring after years of low water.

While fisheries biologists all around the state are excited about the possibilities on their respective lakes, few are more stoked than district supervisor Randy Myers is about Lake Medina.

“It’s been like a ghost town out there for a lot of years, but not anymore,” Myers said. “It’s going to produce some great fishing for years to come, provided something crazy doesn’t happen.

Located near San Antonio, 5,000-acre Medina was 86.08 feet below full pool (4.3 percent capacity) when the floods came last May. Within three months the water level jumped nearly 75 feet to more than 75 percent capacity.

Recognizing the potential, TPWD salted the lake with 203,000 Florida bass and 67,000 blue catfish. Not surprisingly, the fish have fared well amid the maze of terrestrial cover that grew while the lake was low. 

October electrofishing surveys performed at Medina turned up 341 bass per hour, which is 449 percent higher than the historic average. “Most of those fish were 7-9 inches and some up to 13 inches — the are growing like they are on steroids,” Myers said. “These were obviously all fish born this year, some through natural reproduction, There are swarms of bass everywhere out there. It’s unbelievable. The shad and bluegills have exploded, too.”

Myers said electrofishing surveys performed at Lake Falcon show that population has also made some serious strides. Biologists collected 91 bass per hour at the fabled reservoir along the Texas/Mexico border, which is double the historic average.

“Most of those were in the 4-7 inch range,” Myers said. “I’m thinking a lot of the fish spawned in June down there, maybe later. That lake is definitely on the upswing. The habitat conditions are really good at Falcon. It’s like a jungle down there with all the brush. Hopefully, we’ll get another boost (in water level) this winter and we’ll get another giant year class down there. When those fish mature, things could really explode. That’s what happened in the early 2000s.”

Fisheries biologist John Moczygemba of Pottsboro says several lakes in his district have experienced similar population booms.

“The bass, sunfish and shad have all exploded on lakes Weatherford, Nocona and Ray Roberts,” he said. “We saw a lot of 7-10 inch bass fish on those lakes in our electrofishing surveys. We’re hearing the same thing happened at Bridgeport, Texoma and Lavon. They also had real good striper spawn on Texoma with all the inflow. We lost some stripers through the spillway, but they will rebound. The fishing is going to be real good in years to come.”

Fisheries biologist Kevin Storey of Tyler is equally excited about the future of several lakes in his district, particularly at Lake Fork, where flooded willows, buck brush and other terrestrial vegetation have made helped improve the lake’s habitat.

Storey said the numbers from his fall electrofishing collection were not available at  press time, but pointed out that 8-10 inch fish were extremely abundant in the survey. 

“That’s great news for Lake Fork,” Storey said. “Those fish should grow into the slot within 3-4 years and they will have a big influence the number of fish that anglers are able to catch.”

Storey added that fall rains helped Fork’s maintain near full pool water levels going into winter. That should bode well for another banner spawn in Spring 2016 and provide another strong year class of offspring.

As bright as the prospects are across much of the state, some lakes continue to starve for water.  As of Oct. 31, Lake O.H. Ivie was only 12.8 capacity; O.C. Fisher, 16.4 percent; Oak Creek, 24.8; Sweetwater, 11 percent; Twin Buttes, 5.3 percent; Palo Duro, 5.2 percent; Meredith, 24.5 percent; Mackenzie, 16.5 percent;  and Hubbard Creek, 37.3 percent.

But there is a silver lining to it all. The skies will eventually open and the lakes will refill, resulting in another round of trophic upsurge to turn another group of tired honey holes into vibrant fisheries again.

 

—story by Matt Williams

 

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