Jason McAlister stood before a group of about 100 city planners, architects and homebuilders at the Blackland Research and Extension Center in Temple last week and introduced The Stream Team. These research professionals have volunteered their skills to develop innovative strategies and solutions for the complicated problems facing Central Texas waterways. They will also organize meetings and workshops, and provide educational materials.
For a city its size, McAlister said, Temple has significant storm water runoff.
“People are trying to get rid of water as fast as they can, and (they’re) forgetting about dissipating energy,” McAlister said. “We will continue to have flood events, the city will continue to grow, streams will try to adjust.”
That energy that McAlister is trying to dissipate, or slow down, often carves out large cuts in creek banks that can threaten homes, parks and businesses.
At the symposium, speakers from across the state - San Antonio, Austin, Weatherford - presented images of washed out parks, bridges and other infrastructure that could have been prevented by better planning.
“The Stream Team is basically a way of getting that information out there when people need to know what can I do,” McAlister said. “Not just landowners, but the big players that are making an impact in the watershed that are building shopping centers.”
Kenneth Mayben appeared at the Stream Team symposium because he was involved in a similar team in North Texas for a decade and helped mentor the Blackland Stream Team.
“Flooding isn’t anything new … stream bank and watershed erosion are natural processes,” Mayben said.
Marie Vanderpool, a hydraulic engineer who worked on a stream restoration project near Dallas, said engineers should be creative, and flexible.
“We should integrate softer solutions into environments. As engineers we’re not always interested in concrete,” Ms. Vanderpool said.
So, how do you slow down a torrent, without inhibiting growth? Engineers offered these ideas.
Starting in the creek bed, landscapers build a series of tiers, called benches, on both sides of the creek until you have reached the elevation where the waterway is at its capacity - called bank full.
Planting native plants such as switchgrass along the banks and in the floodplain can also work like a sponge and slow down floodwaters. Reinforcing banks so they won’t wash out - engineers call it holding the tow - can be accomplished by using native rock, or planting a mix of native grass, shrubs and trees.
One engineer presented a graph that claimed grass and tree roots intertwined on a stream bank are as erosion-resistant as concrete. The aesthetic and wildlife values are an added benefit, he said.
The experts presented example after example where normally placid creeks have turned angry and gobbled up creek banks, washed out large trees and threatened nearby roads and farms. Mayben and others explained that this is a natural phenomenon - waterways are constantly changing and self-regulating, but the problem is often exacerbated by urbanization.
However, when a stream carves out a steep bank, it is trying to rebuild a floodplain that was probably altered by construction upstream. The stream is simply trying to find its equilibrium.
John Lloyd Reilley, a plant materials expert, said today’s streams have often become drainage ditches, and half of the waterway problems in the United States are a result of urban runoff. He presented a comprehensive list of native plants that could replace those ugly, concrete embankments and provide aesthetic value.
“Property values almost always go up because now you don’t have a ditch, you have an asset,” Reilley said.
Managing storm water runoff is nothing new for researchers at BREC.
From 2003 to 2006, research scientists conducted a restoration project along Friar’s Creek in South Temple. As Temple grew, Friar’s Creek was forced to carry more runoff, and morphed from a placid stream into a sometimes frothy, brown torrent. The result - undercuts in the bank that created both an eyesore and a danger. During the project, McAlister said researchers decided they wanted to share their experience with others.
“What we hope to do with the Stream Team is offer that kind of advice, expertise and knowledge of these things and spread it around. Try to get away from just the traditional techniques,” McAlister said.
“If it doesn’t cost you now to deal with a stream, it will cost you later.”
fafflerbach@temple-telegram.com
