Friday, July 10, 2015

Mt. Tam herbicide plan dropped More costly options studied to eliminate invasive vegetation

By Mark Prado @MarkPradoIJ on Twitter
A controversial plan to use toxic herbicides to rid Mount Tamalpais of broom and other problematic invasive shrubs has been dropped by the Marin Municipal Water District.
The decision was cheered byenvironmentalists and others, but there is likely a literal price to pay to help finance removal of invasive vegetation that has exploded on the mountain in recent years.
The water district used the herbicide glyphosate, the chemical found in Roundup, for three years until August 2005, when its board of directors suspended its use after complaints from residents concerned about potential health impacts if the chemical leached into reservoirs.
The issue has been studied ever since with the district developing two plans — one of which used herbicides — to rid Mount Tamalpais of the flammable vegetation. But citing a recent World Health Organization report classifying glyphosate as a possible cancercausing agent, water board staff recommended removing herbicides from further consideration.
On Tuesday the water board agreed, voting unanimously to walk away from herbicide use.
“There are things to consider, like the fire risk and plant diversity that is being hurt by the broom, but our technical staff said it was time to pull away from (herbicides),” said board president Jack Gibson, adding that the debateover glyphosate was stagnating as the weeds continued togrow on Mount Tam.
There is the equivalent of more than 800 football fields of broom on the mountain, and that grows by 30 to 60 acres a year. Proposals had called for a limited use of herbicide to control the broom, but that has been opposed by some.
“We had to get this off the table to move forward to address the

larger issue,” Gibson said.
Belvedere resident Dr. Bill Rothman of the antiherbicide Marin Water Coalition lauded the decision.
“The more that is learned about pesticides, the more the danger becomes apparent,” Rothman said. “You are talking about an area where our water comes from and where people hike and take their children and pets. People want to feel secure.”
The decision does come with some catches. In August, the water board is expected to look at raising rates to help pay for programs to pull the broom by hand or mechanical methods.
A 2012 water board study indicated it would cost the district $5.8 million a year to manage broom without herbicides and $1.6 million annually if chemicals were employed.
The rate increase is also needed because less water is being sold during the drought, water officials said.
“We will have to do something, there is no doubt about that,” Gibson said, adding he hopes volunteers will also help with the broom-pulling efforts.
The district manages 22,000 acres of the Mount Tam watershed. Mount Tam is also home to more than 400 kinds of animals and 900 types of plants, including seven found nowhere else in the world. District officials worry the broom could choke off the natives.
In addition to protecting biodiversity, ridding the mountain of broom is critical to guarding against a catastrophic wildfire. More than 25,000 homes are in the fire-prone neighborhoods bordering Mount Tam.
Marin County fire Chief Jason Weber said he hopesthe water district can now move ahead with removing the broom.
“The good news is the district has been struggling with this for the last 10 years, and very little work has been done. Now it looks like they are prepared to make the investments and hit the ground running,” he said, adding there is a “huge” fire threat in Marin. “But there is a lot of work ahead.”
Dubbed the “Rasputin of plants,” the broom has thrived despite repeatedattempts to kill it off with everything from flame throwers to foam to herds of goats.

“It might come down to just pulling by hand,” Gibson said. “But there may be some mechanical devices that we can use as well.”

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