Eutrophication

What is Eutrophication?

The term eutrophication is now generally used, even by most scientists, to describe both nutrient levels (the amount of foodstuff available for plant growth) and the natural “aging” of a lake. Eutrophication is the process of increased nutrient input to a lake over the natural supply. From the instant that a lake is created, the aging process, or filling-in, begins. Material is carried from the watershed by streams, wind and direct runoff to become deposited in the lake. They also age at different rates because of differences in geology, runoff and watershed characteristics.

Bungay is considered a eutrophic lake, one which is shallow with a soft mucky bottom. Rooted plant growth is abundant along the shores and out into the lake, while algae blooms are not unusual. The water is often colored, with suspended and organic matter reducing its clarity. Eutrophic lakes support only warm water fisheries such as perch, horned pout and bass.

Any activity in which man increases the rate of incoming materials (such as land clearing, and watershed development) or increases the nutrient loading (septic leaching, fertilizers, etc.) will hasten this aging process. This is often called cultural eutrophication.

Why has Bungay filled in or “aged” so much over the past 40 years?

As we learned above, all lakes gradually fill in over time. If a lake is experiencing a nutrient overload, it will fill in much faster that one that isn’t. At one time, Bungay Lake used to be 90% summer cottages. Over the past 30/40 years, we’ve reversed that to 90% full time residences. This results in nutrient overload that is nearly 6 to 10 times the previous amount. The chart below shows typical phosphorus levels for cottage living compared to year round living.

Cottage Living

-Human Waste = 534 grams, -No Dishwasher = 0 grams, -Doesn’t Fertilize = 0 grams, -Wooded Lot = 17 grams, -Phosphate Free Household Products = 0 grams, -Total = 551 grams

Year Round Residence

Human Waste = 1534 grams, -Dishwasher, Powdered Detergent = 651 grams, -Fertilizes Lawn Twice per Year = 1962 grams, -Clears Lot = 29 grams, -Household Products Containing Phosphates = 180 grams, -Total = 4356 grams

Bungay Lake is the way it is today mostly because of the way we have been treating it over the past several years. See articles on nutrient reduction in this archive to discover what YOU can do to help prevent nutrient overloading.

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