JEFFERSON – In an effort to help reduce phosphorous levels in Lake Hopatcong two floating wetland islands were installed in the lake just off the shoreline in Ashley Cove in the township.
The cost of the islands is covered under the existing 319(h) grant that was awarded to the Lake Hopatcong Commission by the New Jersey Department of Environmental Protection in 2010 and has been recently
administered by the Lake Hopatcong Foundation.
Each island is made up of five small “cells,” measuring 250 square feet and made from woven recycled plastic material with holes available for planting vegetation. Within one growing season the islands will be
lush with vegetation, a kind of floating garden.
According to Donna Macalle-Holly, grant and program administrator for the Foundation, approximately 100 native plants were planted on each island, keeping the edges free of vegetation to allow turtles to
sun themselves. Netting was also added to prevent birds from nesting on the islands or eating the vegetation.
On a sweltering day in July, Macalle-Holly, along with two Jefferson Township DPW employees, Todd Hackett and Dave Mayer, Dr. Fred Lubnow, director of aquatic programs with Princeton Hydro (the environmental consulting firm for Lake Hopatcong) and Casey Hurt and Richard Ampomah, both from Princeton Hydro, planted seven different native plant species, including sweet-scented joe-pye weed, hibiscus moscheutos, common rush, New England aster, broadleaf arrowhead, great blue lobelia, and golden zizia in each of the islands before they were floated out and anchored in the cove. The plants will attract birds, butterflies and bees, said Lubnow.
Ashley Cove was chosen because of the ground water that flows from Espanong Road directly into the lake, said Lubnow. The theory is the islands will intercept the runoff from the road, trapping the nitrogen and phosphorous, reducing choking weeds from taking over the three-acre cove.
Lubnow, Hurt, Ampomah, and Macalle-Holly coordinated the Ashley Cove project. According to Lubnow, the islands create “an excellent habibat” for phosphorous removal and will eliminate “about 10 pounds of phosphorous” material.
Nutrients and phosphorous materials are drawn to the roots of the plants peeking through the bottom of the islands, which in turn feeds the plants and helps prevent other nuisance vegetation from growing in the cove.
Another benefit, said Lubnow, is to the fish, which tend to “gravitate to underneath the islands because of the algae, which will start to form, creating a whole little community.”
Lubnow, citing a study by Floating Islands International, said, “80 percent of the phosphorous is taken up by the microbes in the (island) material and about 20 percent go to plants.”
This type of wetland island has a life span of about 15-20 years, is made from an “inert” material and will require little to no maintenance, said Lubnow, who has been installing wetland islands throughout New Jersey and Pennsylvania for four years. Lake Hopatcong is the first state-owned lake in New Jersey to get floating wetland islands said Macalle-Holly.
“This is the first of a kind water quality improvement project for Lake Hopatcong,” said Macalle-Holly.
Jessica K. Murphy, president of the Lake Hopatcong Foundation, said the “islands are a project that gets right to the heart of the LHF purpose.”
“We focus a lot on the Lake Hopatcong community and experience, but none of that will matter if the lake itself isn’t healthy,” Murphy said.