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What is the future of Cape’s Dam?

Guest Column
Sunday, September 2, 2018

Cape’s Dam is damaged. There’s no question that it’s unsafe for recreation, unattractive, and preventing the utilization of what could be beautiful park space on the San Marcos River. What’s less clear is whether removing or reviving the dam will better benefit our community.

The issue has been hotly debated in San Marcos, and that emotional and personal involvement has hindered the conversation and left an ominous void in what should otherwise be a community discussion.

But let’s start with what we do know. Cape’s Dam is over 150 years old. It provides enough water to sustain the millrace channel. Both remove/ repair advocates agree that without the dam, that millrace will have little to no water in it, leaving a bare trench with exposed tree roots and eventual deterioration.

There are many aspects to consider, including the historical value discussed in last Sunday’s Record. Here are some ways altering the dam could affect us here and now.

The Community

Longtime canoer Tom Goynes doesn’t like dams, but he does enjoy rapids.

“They both hold back water except one of them is made of boulders and it’s fun to shoot through in a canoe,” he said.

Goynes believes rapids would serve the same purpose for Cape’s Dam as they have for Rio Vista. This way, the millrace would continue to be filled and the dam would no longer obstruct downstream canoeing.

Kayaking and canoeing have long been community traditions, now proving more and more difficult.

Disabled veterans, particularly, accessed the river at the entrance to the millrace at Cape’s Road. Canoers and kayakers were able to easily put their craft into the gentle flow of the millrace channel.

But the park has been closed since the city took ownership of the area in 2014, because of the unsafe conditions of the dam.

TG Canoes owner Duane TeGrotenhuis regularly rented canoes to boy scouts and other youth groups who came during the summer, and says he always had groups use the left (millrace) channel. The main river channel is not safe for beginners, he says.

“The right-hand channel twists and curves and winds, and for folks who don’t have a lot of time canoeing or kayaking, it’s a real problem,” Te-Grotenhuis said. “If we take out the dam and people have to go down the right-hand side, we will inevitably lose somebody sooner or later.”

The Environment

The stretch of river affected by Cape’s Dam is federally protected by U.S. Fish and Wildlife as a critical habitat for endangered species. Specifically, the river is home to Texas Wild Rice and the Fountain Darter.

A local endangered species biologist, who does not wish to be named, says this federal protection requires that any project impacting the area must be reviewed closely.

She says removing the dam would completely disrupt that habitat, which is backed by many studies on dams pre- and post-removal.

“It’s going to increase flow, it’s going to make the water shallower,” she said. “When those two things happen… you have a change in your (habitat) composition.”

We have a responsibility to do proper evaluations before making such a drastic change to the river. Some argue removing the dam would return the river to its “natural state,” yet by altering the way the river has adapted to, and thrived with, the dam in place for 150 years.

We saw an example of the Texas Wild Rice’s dependence on the dam in 2000 when the dam breached.

According to the article by now-editor of the San Marcos Record Anita Miller, the water from Cape’s to Rio Vista dropped over a foot, necessitating the relocation of TWR. Many plants were left exposed and dying on the surface.

This evidence is indisputable. TWR will struggle in lower water levels, which current removal advocates also argue will even out to normal levels with sediment displacement after the dam is removed. Even if it does, will it still be hospitable for the TWR? Or will the TWR die, exposed, before the sediment rearranges itself?

The city bases their “remove” verdict on a single study by Thom Hardy. While his research is not thorough, it’s not our job to say whether his conclusion is right or wrong. The problem is that this is only one study, and this study has neither been peer-reviewed nor publicly released.

Our options

Drew Wells of San Marcos Parks and Recreation said U.S.Fish & Wildlife has pulled their funding for removal and the city is reassessing their options, but gave no further details.

Goynes suggests replacing the dam with Rio Vista-like rapids, which also acts as a fish ladder for fish passage. The water would be maintained in the millrace and canoers can easily pass downstream.

A 1998 proposal for Cape’s Dam sought to create a dam similar to the wire-wrapped rock structure that exists. It also proposed control works to manage water levels in periods of drought, to maintain a healthy water level for wild rice.

Similar structures have been used with success, the proposal says. They are economically feasible and able to withstand flood events. Cost was estimated at $608,000, and also supported by the Austin Ecological Services. But the project was not funded and shuffled aside.

Restoring or otherwise altering the dam to maintain water in the millrace would be more likely to draw grants for the project than removal. Federal environmental protection is what will give dam removal advocates an uphill battle. None of the permits in order to remove the dam have been approved. The city is again, essentially, at square one.

And since we’re at square one, perhaps this is an opportunity to rethink what the community really needs and wants from this project.

Candice Brusuelas is affiliated with the group Save the SMTX River