Save Minnewawa Association was formed in 1977 and they purchased their first aquatic vegetation harvester in 1982. Since the harvester has been in use, not only have the amount of weeds decreased, but the water clarity has significantly increased.

A big reason for this is because there are fewer weeds dying in the lake and decomposing in the bottom of the lake. Also, the weeds contain a huge amount of phosphorous which is being removed along with the weeds. The more phosphorous in a lake, the more algae growth, therefore the lower the water clarity.

The board has heard the suggestion of controlling the weeds by using chemicals instead of the weed harvester. The cost of the chemicals is very prohibitive though. It was $250,000 dollars and the lake had to be treated twice a year for the first 5 years; a price tag of a half million dollars. Compared to approximately $25,000 a year it takes to run the weed harvester.

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One of the most obvious management activities of the Lake Hopatcong Commission is the weed harvesting program. Some may view this as a simple “mowing” of the Lake. However, much more is accomplished than simply opening boating lanes and improving swimming. The harvested weeds represent a significant amount of biomass, and associated nutrients, that if not removed would otherwise add to the siltation of the Lake and contribute to its future eutrophication.

In its first three years of operation, because of the concerted, coordinated efforts of the Lake Hopatcong Commission, over nine million pounds of weeds were removed from the Lake. This could not have been accomplished without the state-of-art harvesting equipment and the dedicated staff of the Lake Hopatcong Commission. From a water quality perspective, the removal of this much weed mass is very important. The phosphorus associated with these weeds is roughly 1,200 pounds.

Although this may not sound like a lot, a single pound of phosphorus can support over 1,100 pounds of algae. Thus, through the weed harvesting efforts of the Lake Hopatcong Commission in New Jersey, phosphorus, that otherwise would be recycled through the Lake and fuel future weed and algae growth, is removed. This has a direct positive benefit to the long-term water quality of the Lake and the control of the Lake’s eutrophication. As such, the weed harvesting program contributes in more than the obvious way in the revitalization of the lake and the improvement of its water quality.

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