Stronghold in the war over water

As foreign invaders go, tamarisk, a flowery plant that grows along creeks and rivers, may not seem the most insidious.

But it may be the thirstiest — a single plant can consume 200 gallons of water a day. In Colorado, where water is a precious commodity, officials have long struggled with ways to deal with the prolific and tenacious plant.

The Fountain Creek Vision Task Force, formed last year to examine ways of improving the polluted and eroded creek, is looking at how to deal with a massive infestation here. At a recent meeting, members learned there is more to it than just pulling weeds.

“I don’t think there’s a way to stop it, but there’s a way to control it,” said E.Z. Zanghi, a representative of Kansas-based Top Cut Dirtworks, who gave members a presentation about his company’s way of combating tamarisk.

Originally imported from central Asia as an ornamental plant, tamarisk seeds escaped and began taking over stream and riverbanks, according to the National Institute of Invasive Species Science. It is now found throughout the West.

In Colorado, it has driven out native cottonwoods along most major rivers and streams and occupies 45,000 acres. A report by the Grand Junctionbased Tamarisk Coalition, formed to combat the plant, said last year the Arkansas River is the most infested in the state. And two of its tributaries, Fountain Creek and the Huerfano River, have the most tamarisk of any tributaries in the state.

The report said the Arkansas River and communities that depend on its water are losing 53,834 acre-feet of water — more than 17 trillion gallons — a year to tamarisk.

A tamarisk plant can drink 24 gallons more a day than the average American uses in a day (176 gallons).

The coalition has identified several options for controlling tamarisk, none of them foolproof. Options range from cutting it to spraying chemicals to importing animals and even beetles to eat it.

But tamarisk can regrow easily, even from a dead plant, so most methods require frequent monitoring and followup treatment. The cutting must often be done by hand because tamarisk lives in rugged stream-side environs.

At the Fountain Creek task force meeting, Zanghi said his company uses a combination of techniques.

The company has two spiderlike backhoes called “menzimunches,” which move on mechanical legs and can reach areas other heavy machines can’t, he said. They tear out the tamarisk and spray chemicals on the trunk right away.

“You’ve probably got three minutes after you cut it,” he said. “The sap automatically seals itself off. You can spray whatever you want, anything, and it will kill the top, but it won’t make it down to the bottom of the trunk.”

They remove the dead tree immediately and burn it.

“When you do this, tamarisk does not rebuild. They don’t start reproducing because there is nothing left but pure white ash,” he said.

He could not provide a cost estimate. But, he said, “In my opinion, they’re going to have to spend some money to do it.”

Money remains the key issue. Tamarisk treatment is expensive, $800 an acre for tributaries and $1,000 or more for rivers, according to the Tamarisk Coalition.

To remove the tamarisk on the Arkansas River alone would cost $45 million.

El Paso County has been working for years to fight tamarisk along Fountain Creek, which mainly grows from Fountain to the south, said Mark Johnston, the county’s natural resources manager.

But much of the tamarisk-infested land is private property. Last year, the county offered a program to reimburse farmers for 50 percent of the cost of removing tamarisk, but only two took advantage of it.

Fountain Creek Vision Task Force members said they would support a program to help landowners pay for removal, but they wouldn’t want to mandate it.

“It’s not realistic and it’s disrespectful to demand people spend $100,000,” said board member Juniper Katz.

Johnston said the county would consider expanding such programs next year, as well as increasing education for property owners on the impact of tamarisk.

“It’s quite overwhelming, like a lot of the weed issues in the county,” Johnston said. “Over time, we can have success. I’m not discouraged, but there is certainly a lot of work to be done.”

CONTACT THE WRITER: 476-1605 or scott.rappold@gazette.com