Some 140 small flood control dams built with federal money decades ago dot McLennan and surrounding counties, some past their design lifespan and many subject to only light maintenance.
Most of these earthen dams are on private property and out of the public eye, at least until extreme circumstances bring them to attention.
Such was the case in May, when record rainfall caused water in Cow Bayou Site No. 5 near Bruceville-Eddy to come within 4 feet of the emergency spillway, nearly 8 inches below the porch of a nearby cabin, and flood a house built in the inundation easement.
It took quick action by McLennan County to have siphons installed to drain rising water that threatened to overtop the spillway.
![BE Lake (copy)](https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/5/36/5369a7a2-3b22-11ef-9488-1f34fba74a51/664e356abb6f7.image.jpg?resize=150%2C108 150w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/5/36/5369a7a2-3b22-11ef-9488-1f34fba74a51/664e356abb6f7.image.jpg?resize=200%2C144 200w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/5/36/5369a7a2-3b22-11ef-9488-1f34fba74a51/664e356abb6f7.image.jpg?resize=225%2C162 225w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/5/36/5369a7a2-3b22-11ef-9488-1f34fba74a51/664e356abb6f7.image.jpg?resize=300%2C216 300w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/5/36/5369a7a2-3b22-11ef-9488-1f34fba74a51/664e356abb6f7.image.jpg?resize=400%2C288 400w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/5/36/5369a7a2-3b22-11ef-9488-1f34fba74a51/664e356abb6f7.image.jpg?resize=540%2C388 540w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/5/36/5369a7a2-3b22-11ef-9488-1f34fba74a51/664e356abb6f7.image.jpg?resize=640%2C460 640w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/5/36/5369a7a2-3b22-11ef-9488-1f34fba74a51/664e356abb6f7.image.jpg?resize=750%2C539 750w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/5/36/5369a7a2-3b22-11ef-9488-1f34fba74a51/664e356abb6f7.image.jpg?resize=990%2C712 990w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/5/36/5369a7a2-3b22-11ef-9488-1f34fba74a51/664e356abb6f7.image.jpg?resize=1035%2C744 1035w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/5/36/5369a7a2-3b22-11ef-9488-1f34fba74a51/664e356abb6f7.image.jpg?resize=1200%2C863 1200w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/5/36/5369a7a2-3b22-11ef-9488-1f34fba74a51/664e356abb6f7.image.jpg?resize=1333%2C959 1333w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/5/36/5369a7a2-3b22-11ef-9488-1f34fba74a51/664e356abb6f7.image.jpg?resize=1476%2C1061 1476w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/5/36/5369a7a2-3b22-11ef-9488-1f34fba74a51/664e356abb6f7.image.jpg?resize=1698%2C1221 2008w)
Contractors in late May prepare to install flexible 18-inch diameter plastic pipe to speed the drainage of the lake at Cow Bayou Site 5 near Bruceville-Eddy.
Nearly all of these dams were built 35 to 70 years ago with 50- to 100-year design lifespans. That is not necessarily a cause for alarm, according to officials with McLennan County and the federal Natural Resources Conservation Service, whose predecessor agency built the dams.
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With property maintenance the structures are highly unlikely to fail, said Adele Swearingen, a spokesperson for the NRCS.
Still, McLennan County engineering officials, who oversee maintenance on some of the dams, are applying for state and federal funding for rehabilitating some of the aging structures.
A 2019 study that Fort Worth engineering firm Freese and Nichols performed for the county found four dams to be in poor condition and a total of 20 that required rehabilitation to meet the Natural Resources Conservation Service standards in place at that time.
![Robinson water](https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/2/8f/28fd2eec-3552-11ef-98c5-cff62e530451/667eba3e4bcd4.image.jpg?resize=150%2C101 150w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/2/8f/28fd2eec-3552-11ef-98c5-cff62e530451/667eba3e4bcd4.image.jpg?resize=200%2C135 200w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/2/8f/28fd2eec-3552-11ef-98c5-cff62e530451/667eba3e4bcd4.image.jpg?resize=225%2C152 225w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/2/8f/28fd2eec-3552-11ef-98c5-cff62e530451/667eba3e4bcd4.image.jpg?resize=300%2C203 300w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/2/8f/28fd2eec-3552-11ef-98c5-cff62e530451/667eba3e4bcd4.image.jpg?resize=400%2C270 400w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/2/8f/28fd2eec-3552-11ef-98c5-cff62e530451/667eba3e4bcd4.image.jpg?resize=540%2C365 540w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/2/8f/28fd2eec-3552-11ef-98c5-cff62e530451/667eba3e4bcd4.image.jpg?resize=640%2C432 640w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/2/8f/28fd2eec-3552-11ef-98c5-cff62e530451/667eba3e4bcd4.image.jpg?resize=750%2C506 750w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/2/8f/28fd2eec-3552-11ef-98c5-cff62e530451/667eba3e4bcd4.image.jpg?resize=990%2C668 990w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/2/8f/28fd2eec-3552-11ef-98c5-cff62e530451/667eba3e4bcd4.image.jpg?resize=1035%2C699 1035w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/2/8f/28fd2eec-3552-11ef-98c5-cff62e530451/667eba3e4bcd4.image.jpg?resize=1200%2C810 1200w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/2/8f/28fd2eec-3552-11ef-98c5-cff62e530451/667eba3e4bcd4.image.jpg?resize=1333%2C900 1333w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/2/8f/28fd2eec-3552-11ef-98c5-cff62e530451/667eba3e4bcd4.image.jpg?resize=1476%2C997 1476w, https://bloximages.chicago2.vip.townnews.com/wacotrib.com/content/tncms/assets/v3/editorial/2/8f/28fd2eec-3552-11ef-98c5-cff62e530451/667eba3e4bcd4.image.jpg?resize=1752%2C1183 2008w)
Soil Conservation Service Site No. 1 Reservoir of Castleman Creek near Robinson, seen in the last week of June, around 28 days after the record-setting 15.28 inches of rain in May.
Engineers estimated that rehabilitating the 20 dams would cost a total of $67 million, with the least expensive being $500,000 and the most costly being $8 million. The county submitted the report to the Texas Water Development Board, the Texas State Soil and Water Conservation Board, the Texas Commission on Environmental Quality, and the Natural Resources Conservation Service, County Engineer Zane Dunnam said.
“We are hoping to receive funding from the Legislature in FY 2025 to provide for engineering design and construction to rehabilitate the first dam of those needing upgrades,” Dunnam said.
In 2023, the Texas State Soil and Water Conservation Board approved the county’s application to rehabilitate its first priority dam, Tehuacana Creek Dam No. 21, and state and federal funding became available later that year to start planning the project.
The NRCS hired engineering consultant AECOM to evaluate options for dam rehabilitation, and the firm presented alternatives in November. A second public meeting is planned later this year to take input on the plans.
Most of the soil conservation dams in McLennan and surrounding counties are maintained by local watershed authorities through small tax levies on property owners in the watershed.
The 140 small earthen dams in McLennan, Bosque, and Hill Counties were built primarily within the watersheds of Richland Creek, Hog Creek, Castleman Creek, Tehuacana Creek or the Cow Bayou watershed. A federal agency called the Soil Conservation Service was responsible for the construction of many these dams from the 1950s to the 1980s before it was subsumed into the Natural Resources Conservation service in 1994.
Of those dams, nine were built in the 1950s, 122 were built in the 1960s and ’70s and 11 were built in the 1980s. Nearly all of the flood control structures in the area get regular maintenance during each year and all get periodic inspections.
Hog Creek, Castleman Creek and Tehuacana Creek watersheds each has a governing body with taxing authority to fund regular maintenance. Richland Creek watershed has five soil and water conservation districts contributing to its maintenance.
Cow Bayou, the watershed that includes the reservoir that nearly flooded in May, has no tax or maintenance authority. McLennan County Commissioners Court sets aside $50,000 a year to maintain the Cow Bayou structures that are within the county.
In McLennan County, most dams are in fair shape, but are officially categorized as high hazard or high risk, because people have decided to build their house downstream of the dam, typically in the floodplain and/or floodway, Dunnam said.
The Texas Commission on Environmental Quality requires inspections every five years for those with buildings constructed in the flood easements or too close to the floodplains, Swearingen said.
Swearingen adds that the risk classifications are based on the damage that could happen to structures built downstream in the unlikely event of a dam failure.
The 50-year design life on many of the older dams and 100-year design life on the ones built in the 1980s refers to an economic justification and not any kind of expectation of failure, Swearingen said.
The dams were designed with the expectation that the reservoirs would silt up over the decades, but that process has occurred more slowly than expected, she said.
They are designed so that even as siltation occurs, the earthen structure together with the primary drainpipes and emergency spillways will continue to provide protection for people downstream, as long as they don’t build in the flood easements, officials said.
“When these dams were built, it was thought that if they held back floodwaters for 50 years or 100 years, they would have provided benefit equal to the cost of construction,” Swearingen said.
WATCH: Larry Lehr with the Castleman Creek and Tehuacana Creek watersheds talks about small dams in the area.
Larry Lehr, manager for Castleman Creek and Tehuacana Creek watersheds, described routine maintenance of dams in tour of one of the dams located between Robinson and Interstate 35, south of Moonlight Drive.
He hires students and contractors to mow the grass on the dams and generally sprays against weeds himself.
It is important to control erosion on the faces of the dam, and also of the ground, underneath the primary spill pipe. The primary spill pipe emerges generally from under the center of the dam and pours water out at a controlled flow rate into the plunge basin, Lehr said.
He also contracts to place rip-rap, or large rocks, under pipes where the ground erodes and also along the upstream or downstream face of a dam if he finds erosion there.
“We also remove any tree, shrub or bush that grows in the dam,” Lehr said. “Water may swirl around the roots, causing low pressure, which is bad for the dam.”
Cow Bayou No. 5, near Bruceville-Eddy was one of two small earthen dams that were in danger of topping their emergency spillways in the middle of the May rains. McLennan County Commissioners Court contracted with Moir Watershed Services LLC of Waxahachie on May 21 to install the siphons.
At the Cow Bayou reservoir, the primary drainage pipe that was built to run under the dam had clogged with brush, according to James Moir, owner of the remediation company. The other one, Grade Stabilization Structure #103 in the 100 block of Snider Road near West, was found to have about a dozen feet of beaver pilings in the primary drainage pipe, he said.
After Moir’s employees removed the brush from both drainage pipes on May 22, and for Site No. 5 put in siphons on May 22 and 23, neither tank topped its spillway.
It took between 5 to 6 days for the site near West to drain back to normal, Dunnam said.
Cow Bayou 5 remains higher than normal according to landowners around it. Dunnam said Friday that exact pool height data is not available through the usual tracking sources.
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Shown is a cabin built in a lower-lying area surrounding Cow Bayou Site No. 5 reservoir. On the left is a photo taken May 23 when the reservoir was 44 feet above normal. On the right is a photo taken July 2 when the reservoir has drained at least 20 feet.
Eddie Money, who owns property on the north shore of the Cow Bayou No. 5 reservoir, said water levels rose 45 feet at one point in May, but “now it’s way down.”
“It’s still high, above the drainage structure near the middle of the lake, but I’ve seen it like this a few times over the years that my wife and I have lived here,” Money said.
Money has owned land that continues about halfway across the dam for around 40 years and lived there for the past 30.
He said the siphons were removed about two weeks ago after water receded beyond their effective levels, but the primary drainpipe is allowing the lake level to drop daily.
A cabin on the lake that flooded to a depth of at least 3 feet is now high and dry. Also revealed by receding waters downhill from formerly flooded cabin was camping travel trailer that stood about 9 feet high on its wheels. Waters have dropped completely out of the vicinity of the cabin and travel trailer.
Moir, the contractor, said these flood control structures were never meant to be recreational or to have people build homes around them.
The county is limited by state law in what it can do to protect people from themselves, Dunnam said in a June 24 email.
“If people want to build in a high flood risk area, then we taxpayers may pay in the future for their decisions today,” Dunnam said.