Water agency, city work to curb arundo growth

Heather Merenda, with the environmental services division of the City of Santa Clarita, holds a rhizome from an arundo plant in the Santa Clara Riverbed near the end of Avenue Tibbitts on Wednesday, March 1, 2017. Katharine Lotze/The Signal

SCV Water and the city of Santa Clarita are joining forces to stop a thief stealing about 20,000 acre-feet of water from the Santa Clarita Valley every year.

The thief is called arundo — an invasive nonindigenous type of bamboo — that continues to invade natural habitat along creeks in the Santa Clarita Valley and in the Santa Clara River watershed.

At a recent meeting of the SCV Water Agency to discuss water resources, Steve Cole, SCV Water assistant general manager, warned his peers that arundo is going to be a high-value target.

“The plant sucks up so much water,” he said. “It amounts to about 20,000 acre-feet a year.”

An acre foot of water is about the same as a football field under one foot of water.

“We’ve reached out to the city of Santa Clarita,” he said. “We’re trying to get focused on how best to move forward.

“There’s some interest in trying to get a task force together,” he said. “There was a program called the invasive weed removal plan, and there’s been some interest in getting that back up and running.”

In January, Cole and other water officials joined city staffers — and representatives of the Sierra Club — in working side by side removing arundo from the Santa Clara River watershed.

“We’re trying to do something with the (SCV) Water Agency,” said Santa Clarita Sustainability Planner Heather Merenda, with the city of Santa Clarita.

Unfortunately, she said, the bird-nesting season prohibits arundo removal efforts between February and October, she said.

Nesting season

During the nesting season, arundo removal volunteers are left with a couple of alternatives that don’t involve ripping up the invasive plant.

“Instead, we do a lot of dragging,” Merenda said, referring to volunteers dragging arundo that’s already been cut.

In October, she hopes to mobilize a volunteer effort to actually remove the unwanted weed.

To date, more than 100 acres of the city’s 297 acres of river property have been assessed for arundo and have been treated.

The problem is that the destructive plant keeps growing back.

Workers burn it, cut it down with chain saws and wrap it with chains, then pull it out with tractors — only to see it pop back up because of a root system connected in a mat under the ground’s surface.

A member of the bamboo family, arundo grows 9 to 18 feet tall, though it occasionally towers to 30 feet tall, with leaves 11 inches to 2 feet long and up to 2 1/2 inches wide.

It replaces other vegetation in riparian areas — those with a natural waterway — choking out other plants that provide food for native animals and eliminating shade from native plants that provide habitat for protected species such as the arroyo toad, red-legged frog, western pond turtle and unarmored three-spined stickleback.

The red-legged frog is of a particular concern, Merenda said, since it is sensitive to whatever herbicides are used to kill arundo.

Glyphosate concern

The city has used a chemical on arundo that includes glyphosate, a controversial herbicide commonly known by the brand name Roundup.

Two weeks ago, Los Angeles County supervisors banned the controversial herbicide from being used by county work crews anywhere in the county.

Glyphosate is a key ingredient in the commercial brand by that name. Roundup is a well-known and effective weed abatement method used by many public and private entities.

Merenda said the city is considering the use of an alternative to glyphosate but the alternative herbicide “tends to be a lot harsher” on the habitat.

“With the red-legged frog being threatened and endangered, I can’t use it,” she said. “Right now, we’re trying to figure out what herbicide we can use.”

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