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Massachusetts Water Resources Authority
FOR IMMEDIATE RELEASE
DATE:
November 24, 2009
CONTACT:

Ria Convery, Communications Director
(617) 788-1105, <ria.convery@mwra.state.ma.us>

MWRA LOWERS CHESTNUT HILL RESERVOIR LEVELS
TO COMBAT INVASIVE WEED

MORE INFORMATION

Eurasian watermilfoil - courtesy State of South Dakota

Eurasian watermilfoil
Larger Image

PHOTOS

Newly exposed area of heavy milfoil
Watermilfoil growth at the Chestnut Hill Reservoir

MORE PHOTOS

THE CHESTNUT HILL RESERVATION

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Recreational opportunities, history and more from the Mass. Department
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An invasive weed called Eurasian watermilfoil (Myriophyllum spicatum L.) has taken root along the perimeter of the Chestnut Hill Reservoir.

The weed beds, while abundant, are not expected to spread throughout the rest of the reservoir. Eurasian milfoil thrives in muddy sediments, which are found only along the reservoir’s shoreline. Other habitats within the reservoir basin do not support milfoil growth.

Though currently limited to the water’s edge, the Chestnut Hill Reservoir’s milfoil beds must be kept at bay. Extensive infestation can cause elevated water temperatures and depressed dissolved oxygen levels; floating mats of milfoil are drowning hazards to wildlife and pets.

Native to tropical climates, Eurasian watermilfoil cannot survive when its roots are exposed to freezing air for long periods of time. By lowering water levels, the milfoil can be dehydrated and, at the right time of the year, frozen to death.

This method of controlling aquatic weeds, called “draw-down/freeze-off,” curbs Eurasian milfoil naturally and without the use of pesticides. MWRA plans to perform a draw-down/freeze-off to the Chestnut Hill Reservoir every winter for three years. After that, every other year should suffice.

ABOUT THE CHESTNUT HILL RESEVOIR

The Chestnut Hill Reservoir, bordered by the cities of Boston and Newton, was built in 1870. It holds 500 million gallons of water and would only be activated during a water supply emergency.

 

PHOTOS: EURASIAN WATERMILFOIL
AT THE CHESTNUT HILL RESERVOIR

Newly exposed Eurasian watermilfoil at the Chestnut Hill Reservoir

Eurasian watermilfoil,
newly exposed

Heavy accumulation of debris at Chestnut Hill Reservoir

Area of heavy debris
near the shoreline

Newly exposed area of heavy milfoil

Area of heavy milfoil
growth,newly exposed

Greater exposure of Cambridge slate outcrop

Greater exposure
of Cambridge
slate outcrop

Chestnut Hill Reservoir, Beacon Street side

The Chestnut Hill Reservoir,
Beacon St. side

Eurasian milfoil, submerged

Submerged bed of Eurasian watermilfoil

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Updated December 8, 2009