Connecticut River Coordinator's Office
Northeast Region
 
Drawing of a water chestnut plant - Credit:  U.S. Fish and Wildlife Service
Drawing of a water chestnut plant. Credit: USFWS

Description

Water Chestnut is a rooted, aquatic plant with both floating and submersed leaves. The floating leaves form a rosette and are green, glossy and triangular with toothed edges. The submersed leaves are feathery, and are found whorled around the stem. Plant stems are cord-like and can attain lengths of up to 16 feet. Water chestnut is an annual plant, overwintering entirely by seed. In July the plant begins to produce seeds (called nuts) with 4 sharp spines. Mature seeds are green to greenish brown and sink to the bottom. Seeds may remain alive in the sediment for up to 12 years! Floating black nuts will not sprout. (Please note: this plant species is not the same as the “water chestnut” used in Asian cooking.)

Photo of a biologist hand-pulling water chestnut by canoe - Photo credit:  U.S. Fish and Wildlife Service
Photo of a biologist hand-pulling water chestnut by canoe. Credit: USFWS

 

Habitat

Shallow (< 16 ft) areas of freshwater lakes and ponds, and slow-moving streams and rivers.

Distribution

Water chestnut’s native range is Europe, Asia and Africa. Since its introduction into North America in 1877, it has become a nuisance species because of its ability to reproduce rapidly and form dense floating mats. Water chestnut is presently found in Massachusetts, Vermont, Connecticut, New York, Pennsylvania, Maryland and Virginia. Within the Connecticut River watershed, water chestnut is found in Massachusetts and Connecticut in a few coves, ponds and an impoundment. The seeds, or severed plant parts carrying seeds, may drift downstream. Ducks and geese may also be responsible for the plants dispersal. Canada geese have been seen with the spiny nuts attached to their feathers.

Control

Early detection is the key to control since smaller populations are easier to eliminate than larger ones. It also costs less to control a small infestation because plants can be individually hand-pulled. Large populations require the use of mechanical harvesters or application of aquatic herbicides to achieve control. Infested waters must be treated for 5-12 years to eliminate the invading population. However, some infestations are so extensive (e.g. >300 acres in Lake Champlain) that complete eradication may never be achieved. Many states, including Massachusetts, New Hampshire, South Carolina, Florida, New York and Arizona, have adopted laws to prohibit the intentional distribution of this aggressive plant.

View the This link opens in a new windowwater chestnut profile at www.invasivespecies.gov.

2007 Accomplishments

Water chestnut management takes several forms in the Connecticut River basin. The first objective is to prevent or minimize new infestations through increased monitoring and surveys. The second is to control the spread of existing infestations by removing the plants when they are discovered and periodically thereafter until the population is eliminated. The last is to increase public awareness as the first line of defense against the spread of these exotic plants.

Water Chestnut Management – Removal

Nine-staff days were provided to assist the Silvio O. Conte National Fish and Wildlife Refuge staff in removal of water chestnut at locations including: Cove Island Cove in South Hadley, MA (1,050 lbs), lower Hockanum River in East Hartford, CT (900 lbs), Chicopee River in Holyoke, MA (1,800 lbs), Ashley and Whiting Street Reservoirs in Holyoke, MA (600 lbs), Vinton Mill Pond in CT (600 lbs), Easthampton Ponds in MA (45 lbs), Meadowbrook in CT (440 lbs), and Windsor Canal in CT (300 lbs). Partners assisting in the effort included many volunteers.

Water Chestnut Management – Education

The Silvio O. Conte National Fish and Wildlife Service fact sheet, Water Chestnut: take it out before it takes over!, was distributed via the Internet as part of the educational materials provided to classrooms involved in the Connecticut River basin salmon-in-the-schools programs. Once again over 100 schools received the fact sheet in Connecticut, Massachusetts, New Hampshire and Vermont.

2006 Accomplishments

Water Chestnut Management – Removal

Seasonal staff and interns provided 18 staff days to assist staff from the Silvio O. Conte National Fish and Wildlife Refuge in removing 7.2 tons of water chestnut from the watershed including 4 tons from the Chicopee River and 2.6 tons from Big E Pond in Springfield, MA. Other collection sites included Cove Island Cove and Hadley Cove in South Hadley, MA, Route 5 Oxbow in Holyoke, MA, the upper and lower ponds at Mount Holyoke College in South Hadley, MA, Fannie Stebbins Wildlife Preserve in Longmeadow, MA, Barton Cove in Gill, MA, Hockanum River in East Hartford, CT and Van Horn Park in Springfield, MA.

Water Chestnut Management – Education

The Silvio O. Conte National Fish and Wildlife Service fact sheet, Water Chestnut: take it out before it takes over!, was distributed via the Internet as part of the educational materials provided to classrooms involved in the Connecticut River basin salmon-in-the-schools programs. Once again over 100 schools received the fact sheet in Connecticut, Massachusetts, New Hampshire and Vermont.

2005 Accomplishments

Water Chestnut Management - Removal

East Hartford, Connecticut: Water chestnut removal from Vinton’s Mill Pond.

A total of 400 pounds of water chestnut plants were hand-pulled from the shallow Vinton’s Mill Pond in the Podunk River basin. This once heavily infested site, located above a dam, had thick mats of this aquatic nuisance species throughout the pond last year. The lighter load this year gave the volunteers the hope that their efforts are having a positive impact. The effort was championed by the Connecticut Department of Environmental Protection with the S.O. Conte National Fish and Wildlife Refuge.

East Hartford, Connecticut: Water chestnut removal from the Upper and Lower Hockanum River.

A total of 385 pounds of water chestnut plants were pulled from the Hockanum River site. The plant load was significantly smaller here than last year. The effort was lead by the Connecticut Department of Environmental Protection with the S.O. Conte National Fish and Wildlife Refuge.

Water Chestnut Management – Education

The Silvio O. Conte National Fish and Wildlife Service fact sheet, Water Chestnut: take it out before it takes over!, was distributed via the Internet as part of the educational materials provided to classrooms involved in the Connecticut River basin salmon-in-the-schools programs. Over 100 schools received the fact sheet in Connecticut, Massachusetts, New Hampshire and Vermont. The same information, along with water chestnut pulling opportunities for volunteers, was distributed to participants at the Westfield River Watershed Association Westfield River Symposium in April and the Herrick’s Cove Wildlife Festival in May.

2004 Accomplishments

Water Chestnut Management - Surveys

Springfield, Massachusetts: Twenty surveys at local lakes and ponds uncover one new water chestnut infestation.

A new infestation of water chestnut was discovered at VanHorn Park Pond-Lower Pond in the city of Springfield. Approximately 5-10% of the lower lake was found to be infested with some very thick patches of the plant as well as scattered individual plants. Due to the proximity of the Upper Pond, there is now a high risk of infestation there. This discovery was made by staff from the Sunderland Fishery Resources Office who canoed the pond with support from the Connecticut River Atlantic Salmon Commission.

The following Springfield lakes and ponds were inspected and found to be free of water chestnut: VanHorn Park Pond – Upper Pond, Venture Pond, Mill Pond, Quarry Pond, Bass Pond, Porter Pond and ponds associated with this lake, Porter Lake (Upper), Loon Pond, Five Mile Pond, Lake Lorraine, Mona Lake, Long Pond, Springfield Plaza Pond, Blunt Park Pond, Island Pond, Lookout Lake, Dan Baker Cove, Watershops Pond, and Pease Cove. These surveys were conducted by staff from the Sunderland Fishery Resources Office who inspected the water-bodies visually and by canoe pond with support from the Connecticut River Atlantic Salmon Commission.

Water Chestnut Management - Removal

South Hadley, Massachusetts: Water chestnut removal from Cove Island Cove.

A total of seven hundred thirty-five pounds of water chestnut plants were hand-pulled from Cove Island Cove. The cove is located at the confluence of White Brook and the mainstem Connecticut River. Plants were mainly concentrated along the shore though some were scattered throughout the cove. The plants were removed in July before the seeds matured to prevent a spread of the infestation. The effort was initiated by the S.O. Conte National Fish and Wildlife Refuge with the Sunderland Fishery Resources Office and volunteers with support from the Connecticut River Atlantic Salmon Commission.

East Hartford, Connecticut: Water chestnut removal from Vinton’s Mill Pond.

A total of over 5.3 tons of water chestnut plants were hand-pulled from the shallow Vinton’s Mill Pond in the Podunk River basin. This heavily infested site, located above a dam, had thick mats of this aquatic nuisance species throughout the pond. The effort was championed by the Connecticut Department of Environmental Protection with the S.O. Conte National Fish and Wildlife Refuge, the Sunderland Fishery Resources Office, and student volunteers from the East Hartford Middle School Summer Program pond with support from the Connecticut River Atlantic Salmon Commission.

East Hartford, Connecticut: Water chestnut removal from the Upper and Lower Hockanum River.

A total of one thousand sixty pounds of water chestnut plants were pulled from the Upper Hockanum River. The plants were concentrated in a few patches in this ponded section of the river above the dam. An additional 750 pounds of plant were removed along the shore and in a backwater area in the Lower Hockanum River. The effort was lead by the Connecticut Department of Environmental Protection with the S.O. Conte National Fish and Wildlife Refuge, the Sunderland Fishery Resources Office, and student volunteers from the East Hartford Middle School Summer Program pond with support from the Connecticut River Atlantic Salmon Commission.

Water Chestnut Management – Education

The Silvio O. Conte National Fish and Wildlife Service fact sheet, Water Chestnut: take it out before it takes over!, was distributed in February as part of the educational materials provided to classrooms involved in the Connecticut River basin salmon-in-the-schools programs. Over 100 schools received the fact sheet in Connecticut, Massachusetts, New Hampshire and Vermont. The same information, along with water chestnut pulling opportunities for volunteers, was distributed to participants at the Westfield River Watershed Association Westfield River Symposium in March.

Downloads

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Last updated: September 7, 2010
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