Waco looks to Brazos River for backup water supply as drought persists

Stephen Swanson, water treatment manager at the city's Dissolved Air Flotation pretreatment plant near Lake Waco looks over a treatment tank. Water from the Brazos could be piped to the plant in a water emergency.

A view beneath the piers of the Twin Bridges shows Lake Waco's shoreline at 11 feet down.

Stephen Swanson, water treatment manager at the city of Waco's Dissolved Air Flotation pretreatment plant, looks over a containment tank where raw water is treated with bubbles to remove algae.

The city of Waco is setting its sights on the Brazos River as a supplemental water supply in case Lake Waco's level continues to drop this summer.

The lake, which serves Waco and its suburbs, stands nearly 11 feet below normal after 14 months of drought in McLennan County. The city has imposed Stage 2 drought restrictions on water users since July and could impose Stage 3 restrictions by May if the lake continues to drop, city utilities director Lisa Tyer said.

Tyer on Tuesday will provide an update to the Waco City Council about plans to divert Brazos River water into the city water system and mix it with Lake Waco water.

The city has water rights dating back more than a century in the urban section of the Brazos, and it bought additional rights in February 2022 about 30 miles upstream on the river.

Those rights could provide 5 million to 10 million gallons a day to the water system, which has an average daily demand of 22 million to 26 million gallons year-round and a typical summer peak of 40 mgd to 50 mgd.

A view beneath the piers of the Twin Bridges shows Lake Waco's shoreline at 11 feet down.

Tyer said the city would likely tap into the Brazos only in a water emergency, when the conditions are ripe for Stage 4 drought restrictions.

"This is really more of a backup option," Tyer said. "We’re just trying to do some planning if we were to get down to a level that required us to do it."

The lake now stands at 451.2 feet above sea level, down from its normal elevation of 462, and is 58% full.

A lake level of 449 feet, or 50% full, could trigger Stage 3 restrictions, such as limiting outdoor watering to once a week. Stage 4 emergency restrictions, banning outdoor watering altogether, could occur 445 feet, or 40% capacity. Under the drought contingency plan, city officials have discretion to declare restrictions at any stage even before the trigger criteria are met.

Tyer said that in an emergency, the city could act within 30 to 45 days to set up temporary pumps on the Brazos, possibly near Riverside Treatment Plant or the Bosque River below the Lake Waco dam.

The water would be pumped to the city's Dissolved Air Flotation pretreatment plant at the base of Lake Waco Dam to be cleaned up, then directed to the city's two treatment plants.

The city of Waco is setting its sights on the Brazos River as a supplemental water supply in case Lake Waco's level continues to drop this summer. The water would be pumped to the city's Dissolved Air Flotation pretreatment plant at the base of Lake Waco Dam to be cleaned up, then directed to the city's two treatment plants.

The city is also evaluating and preparing to order equipment for a longer-term system that could be delivered in the next six months to pipe river water to the pretreatment plant.

The emergency measures could pump up a maximum 15 mgd, which would exhaust the city's in-town water rights within 12 months.

Under water rights dating to 1914, around the time Riverside Treatment Plant was built, the city can draw 5,600 acre-feet of water, or about 1.8 billion gallons a year, from the river. Under Texas law of seniority, the city's rights have priority over any rights in the Brazos basin created since then.

The Riverside Treatment Plant on University Parks Drive was built to take water from an intake nearby on the Brazos River. City leaders are considering using that intake point again if drought persists.

City leaders are looking to extend the river supply with 2,153 acre-feet of water rights it acquired last year along with 628 acres it bought at Smith Bend on the Brazos River near Lake Whitney Dam for $4.3 million. Those rights date back to 1921 and are senior to most rights in the Brazos basin.

Tyer said the city has been in conversation with Texas Commission on Environmental Quality officials about getting permission to use those water rights at an intake downstream in Waco. That process would involve public hearings and could take about a year, Tyer said.

The city could further extend its river water supply by getting TCEQ approval to pipe treated effluent from its wastewater treatment plant back upsteam past the low-water dam into the in-city stretch of river known as Lake Brazos. Since the lake is considered to extend all the way to the Lake Waco spillway nine miles upstream, city officials hope to be allowed to withdraw an equivalent amount of water there, Tyer said.

She said a consultant will make recommendations on that option next month, she said.

Stephen Swanson, water treatment manager at the city of Waco's Dissolved Air Flotation pretreatment plant, looks over a containment tank where raw water is treated with bubbles to remove algae.

Few Texans drink out of the Brazos River because it contains salt from saline springs on the Salt Fork of the Brazos in West Texas. Normal treatment processes do not remove salt, so the city's strategy would be dilution.

"It's a very different quality of water than what we use from Lake Waco," she said. "You would definitely notice a different taste. The idea is that we would send it back to the DAF, blend it with water out of Lake Waco and achieve a more palatable drinking water."

Tyer said she is hopeful the lake will recover in coming months and head off the need to use river water, but it won't be easy.

"Even returning to normal doesn't give us back 11 feet," she said. "It may keep us out of Stage 3. Really, the most realistic outlook may be that it's enough to get us through the summer on Stage 2."

A view beneath the piers of the Twin Bridges shows Lake Waco's shoreline at 11 feet down.

Stage 2 restrictions limiting outdoor watering to two times a week during evening and early morning hours, with exceptions for hand-watering.

The National Weather Service's Climate Prediction Center last week announced the end of La Niña, the Southern Pacific Ocean weather pattern that has contributed to warmer, drier weather in Texas for the last two years.

The agency's models show that McLennan County will see a 43% chance of wetter than normal weather in April, and a 33% chance of near-normal precipitation. Still, the U.S. Seasonal Drought Outlook shows that drought is likely to persist here into June.

Waco Regional Airport has received 5.8 inches of rainfall so far this year, compared to a normal year-to-date amount of 7.5 inches and a 2022 year-to-date amount of 2.6 inches.

The National Weather Service forecast for Waco calls for a 20% chance of showers Tuesday with highs around 70, cooling to the mid-60s Tuesday night. The forecast calls for chances of rain and thunderstorms Thursday and Friday.

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Managing editor

J.B. Smith is the the Tribune-Herald managing editor. A native of Sulphur Springs, he attended Southwestern University and joined the Tribune-Herald in 1997. He and his wife, Bethany, live in Waco and have two children.

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