DEP Employees Paddle With A Purpose, Joining The Fight Against Invasive Water Chestnut

By Sarah Anderson, DEP Intern, Clean Water

This month, DEP employees from the Southeast and Southcentral Regional Offices joined the fight against invasive water chestnut plants in Bucks County’s Lake Towhee. DEP staff have taken this “Paddle with a Purpose” for the past nine years.

From July 18 to 20, more than a dozen DEP employees volunteered with the Bucks County Conservation District to kayak and canoe around Lake Towhee and manually pull out the plants, which have taken over much of the lake’s surface.

These water chestnuts are damaging to native biodiversity and make large portions of the lake virtually unusable for recreation. Manual removal is currently the only strategy available to fight the invasion in Towhee.

The plant material is then dumped inland in the woods to compost.

Each water chestnut plant can drop up to 20 seeds, and each seed remains viable for up to 12 years. This is why the annual effort is so important, to prevent more seeds from spreading and replenishing the seed bank.

In addition, mature seeds are hard and spiky all over. These spikes are sharp enough to penetrate tires, shoes, and skin, making them a major nuisance to recreation in regions where the chestnut is present, in addition to the damaging environmental effects.

The dense growth of water chestnuts stops light from penetrating the surface of the lake and prevents other aquatic plant life from growing. Water chestnuts also outcompete most other plants for nutrients and space.

Both the reduction of other plant growth and the decomposition that occurs when chestnut plants die decrease dissolved oxygen levels, which is damaging to fish and other aquatic life.

Despite intense heat, volunteers paddled for up to five hours each day on the lake. Volunteers gave a total of 540 hours of service during this year’s pull, and some dedicated Southcentral DEP employees even camped overnight in the park in order to participate in all three days of the event.

These efforts were not in vain. Meghan Rogalus, the event’s organizer, reported that this year, 23 pickup truck loads, or approximately 58 cubic yards, of water chestnut plants were pulled by volunteers. This is equal to about two commercial-sized dumpsters.

Since 2009, when the pull first began,the amounts of plant material removed (measured in tons) and volunteer hours have steadily risen.

Ed Filip, Stream Assessment Biologist in DEP’s Southeast Region, has participated in the chestnut pull for the past eight years, and organizes the volunteer effort for the DEP Southeast Regional Office through email signups and carpools. He feels that the project is well worth the time and physical labor.

“The annual Lake Towhee water chestnut cleanup has been going strong for nine years now.  I’ve been involved in all but one of them, so I’ve seen the difference we’ve been making,” said Filip.  “We’ve cleaned up most of the lower half of the lake and the rate of reemergence there is so much better than when we started.  We’ve even made some inroads to the choked-out upper portion; not just holding the line, but pushing back.  

“If it were not for our efforts, most of the lake would be overrun with water chestnuts.  Native plant populations, fishing, boating, recreation: all of these things have improved,” he said.  “And we are helping to keep this invasive species from spreading to the much larger Lake Nockamixon downstream, where it could become an even bigger problem than it is now.

As Filip mentioned, the other major goal of the pull aside from stewardship of Lake Towhee is to prevent its source population of water chestnuts from spreading further to Lake Nockamixon.

In the nine years that chestnuts have been in Towhee, only a very small patch of the plant has appeared in Nockamixon, and can still be removed by volunteers in one afternoon. Participants in the annual chestnut pull at Towhee are fighting hard to keep it that way.​​​​
Click Here for a DCNR factsheet on the water chestnut.

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(Reprinted from the DEP Blog)