ISHPEMING - With the fall yard cleanup season here, the city's Lake Bancroft Committee is asking residents not to dump their lawn clippings and other debris into the Ishpeming lake.
The committee said Lake Bancroft has been affected by an overload of organic matter suspended in the water - known as eutrophication - for many years now. If it isn't reversed, the lake will eventually become a bog.
The Lake Bancroft Committee was formed to protect the lake and help clean it up by trying to reverse the eutrophication. This fall, the group is asking residents to not rake lawn clippings, leaves and other debris into the lake because it would make the problem worse, said the committee's technical advisor, Carr Baldwin.
Due to no flow or out flow, Lake Bancroft is undergoing a process called eutrophication, which is where an abundance of organic matter is suspended in the water causing the lake to be cloudy, grow algae blooms and smell of decay on hotter days. (Journal photo by Adelle Whitefoot)
"The city has programs for getting rid of the lawn waste," Baldwin said. "Lawn waste is all compostable and they have a compost site."
Signs will soon be posted around Lake Bancroft asking residents to not dump yard waste in the lake.
The Ishpeming compost site, located on Sunset Drive, is open from 7 a.m. to 3 p.m. Monday through Friday. The site accepts leaves, brush, yard waste, Christmas trees and other compostable material.
One of the reasons for the lake's eutrophication problem is a lack of water inflow or outflow. The lake level depends solely on how much rain the area gets and the ground water level.
The other factor that effects the lake is fertilizer that residents use on their lawns, Baldwin said.
"If they apply in excess, then the excess fertilizer runs off into the lake when it rains," Baldwin said. "As long as the fertilizer is used up by the grass, it doesn't get into the lake."
The Lake Bancroft Committee's centerpiece cleanup plan involves placing a pump into the lake that will introduce a food-grade polymer to attract sediments and sink them to the bottom of the lake. The water brought into the pump will flow over and through polymer "logs" that will gradually disintegrate, allowing light to penetrate the water and enabling it to reoxygenate.
A healthy lake has oxygen-rich water several feet deep and is oxygen deficient at its bottom. According to the committee, the lake's oxygen deficiency starts at a depth of about 2 feet.
Due to the eutrophication the lake is cloudy, there are algae blooms and smells of decay on hotter days. When the eutrophication is reversed the lake will be clean, can be stocked with fish and the fountains in the lake can be turned back on.
The Lake Bancroft Project is being funded by donations only and is run entirely by volunteers. Donations can be made at City Hall or by mail by indicating "Lake Bancroft Special Fund" on the memo line of the check.
Adelle Whitefoot can be reached at 906-486-4401.