Guadalupe-Blanco River Trust Preservation Matters

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Attack of the River Invaders
River authority battles plants that disrupt water flow

June 29, 2008
Tara Boznick
Victoria Advocate
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Attack of the River Invaders
Photo by Victoria Advocate

GREEN LAKE – A floating green mass threatened to block the passage of the delta landowner's boat down river.

"Here's another blockage," Gene Colville said, pointing at the 120 feet of growth spreading across the Guadalupe River from both banks. "We'll just try to ease and push our way through it."

The driver slowed the boat as it pushed through the tangled water hyacinth – a South American native invading Texas' waters.

"This would become solid if nothing was done," Colville, a 77-year-old who lives in Rockport, said. "And it's been that way before."

That's why the Guadalupe-Blanco River Trust partnered with the U.S. Fish and Wildlife Service to spray herbicides on three invasive species swallowing up the Guadalupe River Delta on Thursday.

The trust's latest projects focused on increasing flow down the river, especially at a time when natural baseflow, like rain, isn't adding to it, executive director Todd Votteler said. In January, the trust finished removing a sandbar from Traylor Cut to ensure freshwater reaches Guadalupe Bay.

Water hyacinth robs the river of about one to two inches of water a day, said Malcolm Johnson III with Johnson Lake Management Service from San Marcos.

His men sprayed four miles of water hyacinth, elephant ear and alligator weed on both banks from Traylor Cut down river. They used an EPA-labeled aquatic herbicide that breaks down into basic elements like carbon, nitrogen, hydrogen and oxygen.

"We can never eradicate it," Johnson said, adding the hyacinth can double in area in one week.

But, hopefully, it would keep the plants from spreading further to keep them from impeding the natural flow of water, Johnson said. The plants will come back in a year.

Colville, who owns 540 acres of ranch land in the river delta, can't remember ever spraying in the area before. About eight years ago, he pulled and cut the plants out with a garden hoe.

When tree limbs start overtaking the river, he trims them. He has also removed 40-foot logs from the river during cleanup programs.

"We take pride in it," Colville said. "We want to see it like it should be."

"That's why the landowner serves as the best steward," Votteler said. The trust, a nonprofit, purchases conservation easements instead of buying up the land to prevent further development.

Ten minutes after passing through the first green blockage, the boat stops at a tumorous growth. About three hundred feet of water hyacinth and elephant ear completely cover the river surface, growing up 3 feet tall in places.

"Wow," Votteler said.

"See how it's grown," Colville said. "It's a good example of why we needed this."