Spring Lake Dam, located near the former Aquarena Springs Park complex, appears deceptively sound, but the three historical floods the dam has endured over the past two years have raised serious questions about its structural integrity.
“The dam was originally built during the Civil War era, primarily out of earth and timber, and recent flooding hasn’t improved anything,” said Eric Algoe, vice president for Finance & Support Services. “This is a public safety issue as well as an environmental issue.”
Repairing the dam is no simple task, and at this point, multiple organizations are involved including Edwards Aquifer Authority, Texas Parks & Wildlife, Federal Emergency Management Agency and the U.S. Army Corps of Engineers. The first phase of restoration is expected to begin next semester.
“A project like this requires close coordination with other entities,” Algoe said. “Many parties are at the table currently, holding an open discussion about how best to go about the restoration. As the property owner, the university is overseeing this dialogue.”
The city is involved, but to a lesser extent, Algoe said. A city representative attends all regular stakeholder meetings. Although the city technically has no direct responsibility regarding the project, there is a clear and obvious interest in public safety and maintaining river quality.
“The first step of the process is identifying ways to ensure that the dam stands for the next hundred years, just as it has past hundred years,” Algoe said. “The university considers the project no less seriously than it does its other responsibilities to repair and maintain campus facilities.”
One of the chief concerns surrounding the project, other than the dam’s questionable structural stability, is construction will disrupt the delicate ecosystem of the San Marcos River.
“Spring Lake Dam, especially the eastern spillway, is an incredibly environmentally sensitive area,” said Thomas Hardy, Chief Science Officer for the Meadows Center for Water & the Environment and biology professor. “The dam has always been leaky to begin with; it was constructed with lots of crevices, and many of those crevices are occupied by endangered species, such as Texas wild rice and salamanders.”
The structural repairs required include lining the dam’s backside with riprap (large boulders, roughly the size of a Volkswagen Beetle or smaller) to keep the dam from washing out on its downstream side. These boulders will hold the dam in place while more complicated and extensive work can be done to the dam’s front, Hardy said.
“Any work done on the dam could potentially have some short-term impact on endangered species,” Hardy said. “But the repairs will protect the dam long-term, and protecting the dam means protecting Spring Lake and its sources.”
The long-term repairs will likely entail a multimillion-dollar project and additional studies and design work on the part of the university, Hardy said. It could be years away.
“Measures to hold the dam in place have to be taken in a way that minimizes the impacts to our endangered species,” Hardy said. “What I proposed in my dialogue with the university was that our team go in with scuba diving gear and manually move the endangered species out of the way of construction long enough for us to place the riprap. We can replant the wild rice further downstream.”
The job is labor-intensive, but delicate. Hardy’s team at the Meadows Center has worked extensively in this field, but as of yet it is unclear whether the university will ask them to participate in the restoration, Hardy said.
“The university is taking this project very seriously,” Hardy said. “They are taking the safety of the dam at same level of seriousness as they are endangered species. They are going slowly and carefully, with an impressive level of commitment.”
Another factor in the restoration project is how to appropriately accommodate the community in plans for the dam’s future.
“We are working together to make recommendations of various ways to present restoration that will benefit recreational users,” said Steve Lightfoot, spokesperson for Texas Parks & Wildlife. “We are here to ensure that the project maximizes usage. We are considering creating paddling trails from the existing ones upstream extended down to Palmetto State Park, as well as additional bank access for fishing and for launching paddle crafts.”
An engineering firm is currently conducting a study to help decide how to best accomplish the repairs, but there is no official cost estimate for the project yet, Algoe said.
Short-term repairs to take place over the course of the next few months are likely to cost roughly $2 million, but the long-term repairs intended to ensure the dam stands for the next century could total up to $5 million, Algoe said.
“We’ve had a regular maintenance review process for the dam for many years,” Algoe said. “The university has been vigilantly monitoring the state of the dam, and has observed more and more water seeping through. The university feels that it is time to renovate and repair the structure, but it’s nothing to be alarmed about.”