Invasive plant threatening the Charles in Newton

by Jim Morrison, Wicked Local Newton
Newton —

An invasive plant from Asia is threatening to choke the Charles River, experts say.

Water chestnuts were almost eradicated in the 1990s, but when the Mass. Department of Conservation and Recreation funding for aquatic weed control was cut about ten years ago, the weed with the sharp-spiked seeds came back with a vengeance and now covers 50 acres in the Charles River Lakes District in Newton, Weston and Waltham.

The heavy growth is restricting access to paddlers and impacting fish and wildlife habitats, and the weeds are spreading downstream, according to Citizens Alliance for NOxious weed Eradication (CANOE).

Water chestnuts grow throughout the Charles River, especially where the current is weak, like in coves or in eddies. That makes the CRLD the perfect place for them to grow.

The invasive weed is native to Asia and is believed to have been growing in the Charles since the late 19th century.

Two Newton legislators are trying to restore funding for the removal of invasive plant species to help save the river.

Sen. Cynthia Creem (D-Newton) wrote a $350,000 fiscal year 2013 budget amendment for invasive aquatic species removal that is on Gov. Patrick’s desk.

Rep. Kay Khan (D-Newton) and Sen. Creem were also able to include another $350,000 in the FY14 budget.

Both bills are sitting on Governor Patrick’s desk, awaiting his signature.

Rep. Kay Khan (D-Newton) said that the House is scheduled for a possible formal session on Wednesday and is hopeful that both appropriations will remain part of the budgets Patrick ultimately signs.

If the funds come through, the money could be used to hire a firm specializing in large-scale aquatic weed control to clear the larger areas of growth, hire weed-pullers, or even buy a harvester.

“There’s a good possibility that the work could begin soon,” said Khan in a phone interview this week.


Living in a watershed

Julie Wood, senior scientist at the CRWA, said that left unchecked, the water chestnut will continue to spread throughout the Charles, turning the river into an un-navigable marsh.

The weeds seem to be growing faster in recent years, possibly due to pollutants in the water.

Recently, the CRWA tested the river water and found it contains twice the amount of phosphorous as the river can handle. The phosphorous is believed to come from automobile exhaust that is removed from the air by rainfall. Runoff from roads and parking lots located in the river’s watershed also carry the phosphorous into the river. The phosphorous may “feed” the water chestnuts.

Wood said that people who live in the watershed can help by building water gardens featuring native plants that thrive in naturally wet areas and don’t require much supplemental water. These gardens absorb phosphates before they can get to the river.

“Everyone lives in a watershed,” said Wood.

Kristin Radcliffe, the CRWA’s the invasive plant removal volunteer coordinator, said she has seen muskrats with water chestnuts in their mouths, but hasn’t actually seen them chew and swallow them.

Larry Smith, owner of Charles River Canoe and Kayak since 1974, has seen that too, and said, “Squirrels love ‘em.”

Smith bought a small harvester in 2012 to pull large areas of the weeds, and it’s operated with funds raised by donations to nonprofits like CANOE.

Water chestnuts can also be hand-pulled by volunteers in what the Radcliffe calls “pulling parties.” Volunteers in canoes can access tight spaces that the harvester can’t.

“Every year,” Radcliffe said, “we have 400 to 500 volunteers come out to pull.”

According to CANOE, last year volunteers hand-pulled over 80,000 pounds of water chestnuts and the harvester cleared another 120,000 pounds. That cleared about four acres in total.

A pulling party was held Sunday with new and experienced volunteers braving the heat and humidity to set out in canoes to pull water chestnuts.

Radcliffe said that it’s important to pull as many of the weeds as possible before they drop their seeds in mid-to-late August.

“Our harvester is small,” said Smith. “It’s well-suited to a volunteer effort designed to make slow, steady progress.”

Anyone interested in joining a pulling party can register here

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