Municipal Employees Enjoy Learning about Lake Hopatcong
As rain splattered the curtains of the new floating classroom, Study Hull, a contingent of municipal clean communities coordinators and other interested adults cruised Lake Hopatcong to learn about the lake.
Donna Macalle-Holly of the Lake Hopatcong Foundation told the students-for-the-day that Lake Hopatcong, the largest lake in the state, has a 5 to 1 ratio of watershed to lake. The mean depth is 18 feet with the deepest part, off Nolan’s Point, 55 feet.
Study Hull launched from the state park. The captain dropped anchor off Chestnut Point, where volunteer instructors Amy Bush and Georgia Schilling taught the group the fine points of water testing.
Macalle-Holly explained that Lake Hopatcong is eutrophic, meaning it is plagued with excess nutrients – mostly phosphorous, which primarily comes from lawn runoff. She reminded the group that lake area homeowners should never use fertilizer on their lawns, unless it has no phosphorous at all. She pointed out that the greenest lawns around the lake also have the greenest weeds in the water.
Bush noted that the lake is in two sections. It was originally Big Pond and Little Pond, formed through glacial action as the last ice age left what is now New Jersey. In the 19th century, the Morris Canal and Banking Company built the dam and raised the lake 12 feet, connecting the ponds. The Little Pond section is the north end of the lake, which is shallower than the rest.
Bush stated that the group would be logging all results of their experiments for the Morris County Environmental Academy students at Jefferson Township High School.
First she showed them Secchi disks, invented by Angelo Secchi and used since 1865 to measure turbidity in the water. The original salt water disk is white; the one used in fresh water is black and white. It is attached to a lanyard marked by the half meter, which is lowered over the shady side of the boat until it is no longer visible.
Bush explained that photosynthesis can take place where the disk is visible. The ideal is to have some photosynthesis in the lake to provide food for fish, but not so much that it encourages weed growth.
Divided into groups of three, the passengers took water samples using a plastic tube and a red plastic cup. The samples were analyzed under microscopes and then compared with photos of zooplankton, phytoplankton, and other flora and fauna in the lake. They also checked the pH and dissolved oxygen in the water. Bush said that finding zooplankton and phytoplankton is good, but that too much plant and animal growth can result in an excess of blue-green algae. An algal bloom can be damaging to the lake.
As for pH, a healthy lake is 5.6 on a scale between 1 and 14. Lake Hopatcong generally tests at between 6 and 8, so it is a little too alkaline, Bush said.
The passengers were also given charts to identify the fish in the lake, both native species and those introduced by fishing clubs.
After the experiments, the captain steered the boat toward the bald eagle nest in Hopatcong. One of the eagles soared around for a few minutes.
At the conclusion of the voyage, a group of municipal employees from Morris County towns discussed the experience. They agreed that school children should take the cruise, but were concerned that budgets for field trips have dropped precipitously.
Kris Johnson, a teacher at Valley View Middle School in Denville, suggested that selected students might participate, such as the environmental club. Kathleen Margiotta of the Morristown Clean Communities program noted that the school programs presented by Dove Environmental ended when Mike and Diana Dove retired recently, and possibly the Study Hull trip could replace them.
The clean communities representatives agreed that the cruise is worthwhile and recommended that school children take it.