Two critical South Texas lakes that supply water to drought-stricken Corpus Christi will rise significantly in the coming days as runoff from last week’s flooding rain flows downstream from the Hill Country.
It is, however, too early to predict if it will be a true “drought buster,” hydrological experts say, or if rising lake levels will push back mandatory water use restrictions for residents.
Corpus Christi, Texas’ eighth-largest city, has been racing to avoid a water emergency in which demand outpaces available water supplies. Earlier this year, city projections showed that “day zero” — when supplies are six months away from being outstripped by demand — could arrive as early as May. Spring rains pushed that estimate back to September 2027, but not before drawing statewide and national attention as the city appeared to be the first major U.S. city to be on track to run short of water.
For months, local leaders said the region needed either steady rain or a hurricane to replenish the largely empty reservoirs. Last week’s intense storms across Central and South Texas, which triggered flash flood emergencies, evacuations and rescues, may deliver some of the hoped-for relief.
The biggest gains (so far) have been at Choke Canyon Reservoir. The lake climbed from 7.9% of capacity on Monday to 14.8% by Friday, almost doubling its water levels. The reservoir was last consistently full in the early 2000s and has been below 50% full since 2013.
“It’s nothing to sneeze at,” said Robert Mace, a water expert and executive director of the Meadows Center for Water and the Environment at Texas State University. He said reservoirs are still rising, signaling that more water is on the way.
Just a few months ago, the region’s outlook was far more dire. In April, the major regional reservoirs reached historic lows — Choke Canyon dropped to 7.4% of capacity while Lake Corpus Christi fell to 8.5%. That same month, at least six small cities and towns in the Coastal Bend region issued disaster declarations amid the water crisis. Corpus Christi, which supplies water to some of its neighbors, told its residents and businesses to cut their water use.
“Even if [Choke Canyon] stopped going up today, it buys Corpus valuable time to pursue alternative supplies,” Mace said.
Rainfall runoff from the Frio, Atascosa and Nueces River systems is expected to contribute vital inflows to both Choke Canyon Reservoir and Lake Corpus Christi.
The Frio River, which flows into Choke Canyon, rose from a depth of around one foot in recent weeks to nearly 30 feet on July 22 in Tilden. At its peak, the river carried roughly 20,000 cubic feet of water per second.
Flows have remained steady, meaning more water is still moving toward the reservoir.
“This flood event has broad shoulders as it’s moving down the river towards these reservoirs,” Mace said.
Greg Waller, a hydrologist with the National Weather Service’s West Gulf River Forecast Center in Fort Worth, said forecasts show Choke Canyon Reservoir could rise a total of 12 feet, bringing it up to 192 feet. The lake is nearing 186 feet, “which is good, but it’s nowhere near full,” Waller said. “This would be good for water supply storage for Choke Canyon.”
While inflows are already reaching Choke Canyon Reservoir, Lake Corpus Christi is expected to begin seeing inflows within the next week. However, forecasting those flows is more complicated.
Waller calls the Nueces River problematic for a hydrological forecaster because it crosses the Edwards Aquifer Recharge Zone. During dry periods, the ground can absorb water before it can reach the reservoir.
How much will the ground suck up? It is hard to predict. Waller said the last five rain events have shown “variable loss” of water. Forecasters expect some water will recharge the aquifer this time as well, but it’s too early to calculate how much.
Corpus Christi officials said in a news release that they are closely monitoring upstream river flows to Choke Canyon and Lake Corpus Christi.
“Our team is continuously tracking upstream gauge levels and coordination efforts across the watershed,” said Nick Winkelmann, chief operating officer of Corpus Christi Water. “We are fully prepared to manage incoming volumes to ensure dam safety, optimize municipal supply storage, and fulfill all regulatory requirements.”
The city plans to hold a meeting next week to discuss what the rising lakes mean for its water emergency.
The Nueces River in Cotulla crested at significant flood levels at 29 feet on July 22 — up from 4 feet in the weeks prior. That water will continue to travel downstream in the coming days.
Waller said that once the water shows up at Tilden, forecasters will have a better idea how much water will make its way to Lake Corpus Christi, which currently sits at 32% capacity. The water could arrive as early as July 27 with a steady rise the first week of August, he said.
“We’re running our modeling to try to share this information, so [the city] can make the best decisions,” Waller said.
Whether the storms will end the Coastal Bend’s drought remains uncertain.
“Texas is a state of drought with occasional massive flooding, and so we’re seeing that,” Mace said.
Still, he cautioned against declaring victory: “We’ll have to see what happens with how much water comes into these reservoirs as to whether or not they’re drought busters for Corpus Christi.”
Disclosure: Texas State University has been a financial supporter of The Texas Tribune, a nonprofit, nonpartisan news organization that is funded in part by donations from members, foundations and corporate sponsors. Financial supporters play no role in The Texas Tribune’s journalism. Find a complete list of them here.
