SPECIAL FX, Summer 2000

Boats and pollution

Did you know?

• That an estimated 30 per cent of all fuel and oil used in two-strake engines ends up in the water?
• That outboard engine emissions can have negative effects on fish - from tainting the flavour to making them dull and sluggish?
• That boat wakes can speed up the aging process (eutrophication) of a lake?

These facts are based on information from three sources:

  1) "Protecting the Aquatic Environment" from the Coast Guard Web site, which says: "Two-stroke engines are the most important source of a persist- ent form of pollution that has devastating effects on the aquatic environment. An estimated 30 per cent of all fuel and oil used in two-stroke engines ends up in the water. Exhaust fumes from both two- and four-stroke engines are of concern because these engines usually lack any form of emission control."

2) An article in the Spring 2000 issue of Cottage Life magazine, which states that according to the U.S. Environmental Protection Agency (EPA), hydrocarbon emissions from outboards and personal watercraft are bad for the air ...and the water. Laboratory studies in the U.S. and Europe suggest outboard engine emissions can taint fish flavour, disrupt the liver and other biological functions of fish, make fish seem dull and sluggish, and even kill fish exposed to extremely high concentrations.

3) Information from the book Polluting for Pleasure by Andre Mele, which was presented at the New York State Federation of Lake Associations, Inc. Annual Conference in 1995. This document says that sediment resuspension and shoreline erosion caused by motorboat wakes can increase the biological
productivity of waters and speed up the process of eutrophication (the aging process of a lake).

Why is this important?

People have been boating on this lake for years, so why should we be concerned now?
The Inter-lacs study done in the summer of 1998 found our lake to be in a mesotrophic state (see "The life of a lake"). In other words, it shows the beginnings of oxygen depletion and is in transition between an oligotrophic and eutrophic lake (with the Newaygo end "clearly in transition to an eutrophic lake").

Essentially, our lake is a fragile, threatened environment and we should be doing everything possible to slow down the eutrophication process. We're not suggesting that boats are the main culprit; that "honour" likely goes to poorly functioning septic systems over the years. And we are concerned about everything - septic systems, beaver dams, shoreline restoration, use of fertilizers and pesticides - that affects the water quality.

What can we do?

The evidence seems to suggest that the long-term goal for our lake should be less, and slower, boating - not more, and faster. That's not to say people should not be able to travel back and forth to their cottages or tour the lake for
pleasure. But it does mean we should at least be aware of the harm motorboats can cause - and take steps to minimize this harm.

There are two things we can do:

Reduce emissions: According to the Cottage Life article, if cottagers want a cleaner, quieter, more fuel- efficient motor under 90 hp, they should consider a four-stroke, which is much cleaner than a two-stroke motor. It will cost more, but you'll save considerably on fuel consumption - and help keep the water cleaner.

Obviously, not everyone can afford to replace their motor right away. So reduce emissions from your two-stroke as much as possible. The Coast Guard recommends keeping your engine serviced and running cleanly and using the correct oil/gas mixture for two-strokes.

Reduce speed: One thing that's very important - and easy - to do is slow down near shore and in the shallow sections of the lake. This can help minimize shoreline erosion and the sediment resuspension caused by wakes.

The Life of a lake

Lakes undergo a natural aging process known as eutrophication. They gradually fill in, becoming ponds, marshes, wetlands, and, eventually, forests. Depending on their trophic states (or how biologically productive they are), lakes can be:
• Oligotrophic:" (clear, nutrient-poor, rich in oxygen - lakes that trout will survive in);
• Eutrophie: (murky, weedy, rich in nutrients, oxygen depletion at bottom)
• Mesotrophic: (somewhere in between)