By Paula Roberts
The staff at DLWA, Kieve-Wavus, and Maine DEP line the entire bottom of a lagoon on Cranberry Cove in Damariscotta Lake on Monday with a thick PVC plastic and rubber blended material to limit the growth of hydrilla. |
A dirty dozen gathered at Cranberry Cove on Damariscotta Lake in Jefferson July 7 to lay down a black liner with the hopes of snuffing out hydrilla discovered there in 2009. Unlike the 1967 movie where convicted murderers were on WWII mission to assassinate German officers, these mud-caked volunteers were on a mission to eradicate the invasive plant from the cove.
Wearing wet suits, and covered with slimy mud, the crew from Damariscotta Lake Watershed Association, the Maine Department of Environmental Protection and Kieve/Wavus worked for the better part of the day unrolling and laying down a new 22 millimeter liner, made with PVC plastic with a rubber blend. The objective is to block out the sun’s rays and starve the invasive species with the ultimate goal of killing it.
Hydrilla is considered one of the worst invasive aquatic plants. It spreads and multiplies in three ways: with a massive underground root system, by seed pods, and sections of the plant that break off, float away and re-root themselves. It can grow a foot in a day, grows in water up to 25 feet deep and can take over a water body, creating a thick mat of vegetation.
“It is called the ‘Godzilla’ of aquatic invasive plants,” DLWA executive director Jody Jones said. “Damariscotta is one of only two public lakes in Maine with hydrilla. In Florida, hydrilla was not controlled soon enough and now lakes must be mowed to allow boat traffic. Installation of the basin liner will provide more permanent and more effective control of this aggressive plant. Monitoring of the site will continue as we measure the plants reaction to the new strategy.”
This is the first time this material has been used in Maine to combat invasive plants. It “has been used successfully in Vermont for the control of Variable-Leaf Milfoil, but it will be the first time it has been deployed in Maine, and the first time it will be used to control hydrilla,” Jones said. “The timing allows us to install the lining before the plant has a chance to start growing rapidly. It also means our volunteers will be working for several hours in chest-high water through deep mud. This project promises to be one of the dirtiest but most satisfying jobs of our summer.”
After hydrilla was discovered in Cranberry Cove in 2009, it was pulled up by the roots, a black plastic liner was laid down, it was treated with herbicide, and a rock berm erected in the winter to control it and prevent it from spreading. One plant was discovered outside the barrier in 2013. Volunteers hope their efforts Monday will eliminate the plant locally once and for all.
“We are initiating a new strategy to control hydrilla,” Jones said. “Once installed, the liner will significantly limit growth of the hydrilla in the cove for up to 20 years. Previous barriers only covered small sections of the cove and lasted only a few years.”
One sprig of hydrilla was discovered during the operation on Monday. “We did not do a thorough survey,” DLWA staff member Garrison Beck said. After the mud has settled in the cove, DEP and DLWA “will monitor it on a regular basis”
DLWA has been pro-active when it comes to invasive plants, taking the approach years ago that it is not if, but when an invasive species would be found in the popular lake. DLWA initiated courtesy boat inspections at the state owned boat launch and discovered invasive plants on boats about to launch into the lake on at least two occasions.
DLWA also started invasive plant workshops, and have taught scores of volunteers to identify invasive plants. These volunteers have monitored the lake since 2008. It was a volunteer that discovered hydrilla growing in Cranberry Cove five years ago.
In 2011, a local resident discovered hydrilla in Davis Stream in Jefferson, a major contributory to Damariscotta Lake. The resident brought the suspicious plant to DLWA to be identified.
Plants have been pulled up by the roots in Davis Stream for the past three summers, and a black plastic barrier was installed in the heavily infested area.
DLWA and DEP survey Davis Stream once a week in the summer months, searching for hydrilla. In 2013, they only found four individual plants. Boats were not allowed above the Jefferson Market last year, but the stream has been opened up this summer.
“DLWA and DEP did not want to restrict access if they did not find a high biomass. We ask that they (boaters) stay in the middle of the channel, so if there are plants, they do not get on the boats,” Beck said.
DLWA is offering an invasive plant patrol field workshop on Friday, Aug. 18. The four hour workshop starts at 9 a.m. To register, call DLWA at 549-3836.
Battling the invasive plant is “a community effort. We are thankful for the support the land owners have given us and the residents, and for the watershed towns for supporting us. We are thankful for the State DEP support as well,” Beck said.
“It was a great day for the lake to see the community coming together, with support from all three lake side towns, DEP, and Kieve/Wavus staff. It was just a great day to celebrate saving the lake. This is a big threat. We are excited to be part of the solution,” Jones said.
