Flooding and wetlands may sound like a perfect match, but a series of floods in the past three years have wrought havoc on the man-made Lake Waco Wetlands, which relies on pumps to move almost 11 million gallons of water per day.
Water returned to part of the Lake Waco Wetlands last week after flooding in May threw the operation into disarray, but the people who know the wetlands best say flooding issues will return sooner rather than later. When the equipment that keeps water flowing in is not operational, the site dries out because its elevation is higher than its water source on the Bosque River.
“That’s the bane of this existence,” Lake Waco Wetlands Coordinator Nora Schell said.
An excavator cleared sediment blocking the channel to the pump last week, allowing water to flow once again. The city pumps water out of the Bosque River and through the wetlands’ four cells, which naturally filter out soils, nitrogen and phosphorus.
“We can show how wetlands are basically nature’s kidneys, because they take in the dirty water and cleaner water goes out,” Schell said.
Once water has passed through, it flows back out into the river and on to Lake Waco.
Best known now for school field trips and Baylor University research conducted there, the city of Waco started work on the Lake Waco Wetlands in 2001 as a way to offset habitat destruction caused by raising Lake Waco 7 feet.
Schell said the site has seen periodic flooding that doubles or triples the water levels, and during floods they shut off the pumps that feed the wetlands. In May, the water rose to 8 to 10 feet above normal.
“Prior to that, the winter and spring before, we had back to back floods come through here,” Schell said. “We knew it was going to bring in a lot of dirt, we just didn’t know how much.”
A channel cut into the Bosque feeds a pipe leading to the wetlands’ pumps. During the last flood, silt filled the channel and blocked it.
“Once the water receded and we were able to really take a good look at it, we realized … we had to clean the pumps, because the water goes all the way into the pump station,” Schell said.
Once the pumps were cleaned and restarted, they would only run for short periods of time. The staff eventually realized a muddy buildup of sediment in the channel was preventing water from reaching the pumps.
“Once we were able to get down to the bottom, we had to go down maybe 13 feet just to get a clear channel flow into there without any obstruction,” Schell said. “Everybody needs to remember we’re on Blackland Prairie clay, so that clay is going to hold a lot of water, and it’s going to get sticky and muddy.”
City workers started digging into the sediment in late June, but were not able to move any machinery into the area until July. Work was further delayed because workers had to complete other utilities projects for the city. Eventually, the city hired a contractor, who cleared the sediment last week.
Schell said since then, the wetlands are looking more like themselves, at least in part. She will continue leading field trips through cells one and two, while the Texas A&M Forest Service is planning a controlled burn in cells three and four.
The wildlife in the wetlands returns on its own, Schell said.
“There’s still things for them to eat, rest in, hide in and make their nests in. They just don’t have the water,” Schell said. “It’s the aquatic stuff that needs to start all over again.”
Schell said the city theoretically could widen the channel to prevent it from filling with silt as often, but a wider channel would be more vulnerable to log jams.
“That’s the million dollar question,” Schell said. “How do we make this area more approachable for the water?”
A permanent solution likely would require redesigning the way water enters the wetlands, said Jon Dulus, an environmental compliance coordinator in the city’s water utilities department.
“It’s not a favorable design to force water into the wetlands,” Dulus said. “We did not have the opportunity to use a gravity-fed system.”
Officials considered a gravity-fed system pulling water in from farther upstream, but the idea ran into a snag when the city realized it would require boring under a county road to pull off, Dulus said. As designed, floods present a challenge.
“Current forecasts predict the same weather patterns for the foreseeable future,” he said. “We do anticipate this happening sooner than later.”
Dulus said to address the recurring issue would require input or permitting from the U.S. Army Corps of Engineers, the county government, the city government, the Texas Commission on Environmental Quality’s Brazos Watermaster for the region, the Environmental Protection Agency and the Federal Emergency Management Agency.
“There’s a lot of players, so we haven’t had many recent discussions on it,” Dulus said. “We’d have to talk with the Corps about how to move forward with that.”
Baylor University maintains research facilities at the wetlands, and its outdoor facility for stream study takes damage every time the wetlands floods.
Robert Doyle, director of Baylor’s Center for Reservoir and Aquatic Systems Research, was involved with the design and construction of the Lake Waco Wetlands. He said it is a valuable research resource with periodic glitches.
“It’s actually a remarkable resource,” Doyle said. “There’s only a few places in the world with something like that.”
He said natural wetlands in areas with variable hydrology are prone to flooding and filling with silt, which can cause their locations to shift from time to time.
“It’s a completely natural part of wetlands and how they work,” Doyle said. “It’s not a tragedy or unexpected.”
However, the Lake Waco Wetlands is supposed to stay put.
“From the very beginning, we knew it was something that would have to be dealt with,” Doyle said. “We’ve just been surprised by how frequently that’s been happening in recent years. It’s a bigger concern because the way that artificial wetlands work, we’re supposed to be able to control that water.”
Doyle said he has discussed the issue with the city of Waco before, but he understands money is a major barrier. He said he would not be surprised if the Baylor research center plays a role fixing the problem when the times comes.
“I’m very interested in making sure the wetlands are here for a very long time,” Doyle said.