Thank you very much, Mr. Chair.
I'm a research officer at the Yves Prairie research lab. We work primarily on carbon in lakes, but we've also done a great deal of research on lake physics, which includes temperature patterns, contaminant dissipation, gases dissolved in the water, as well as the measurement of turbulence and waves on the surface of lakes.
That is why, in 2014, Memphrémagog Conservation Inc.—whose representative has already testified before this committee—and the Société de conservation du lac Lovering asked us to conduct a study on the effect of wake boat waves on the shores of Lake Memphrémagog and Lake Lovering.
Because that 300-metre distance you've been hearing about since the beginning of your study comes from our own study, I'll take the time to explain where that figure comes from and what it represents.
As part of our study, we set out a rigorous protocol, making sure that the wakes we were creating happened at different specific speeds, at different specific distances from the shore and with varying levels of ballast. I want to be clear that wake boats are the only type of vessel we studied.
Our study was investigating sediment resuspension and surface energy, and not directly investigating shoreline erosion. In the case of both lakes, we concluded that it takes a distance of 300 metres for the energy generated by and contained in waves to be dissipated when they arrive at shore and for the effect to be comparable to that of natural winds. In other words, wake boats must travel at this distance from shore for the effect of the waves they produce to be equivalent to the effect of natural waves on the shore.
Lake Memphremagog and Lake Lovering are very different. Figure 9 in our report shows that turbulence decreases according to distance. That's true for both lakes, but it presents itself quite differently. Regardless, we came up with that same 300-metre distance for the energy in the waves to dissipate and be equivalent to the energy in natural waves.
All of Quebec's lakes appeared following the withdrawal of glaciers. They have the same physical creation process. We can therefore state that these lakes are fairly similar in type.
After our lab study, I was involved in a project at Lake Tremblant. We did not take specific measurements using instruments, in this case, but we characterized the shorelines to determine whether certain areas were at risk of being more or less damaged by waves produced by the boats.
What are the shoreline characteristics that mean that the waves' effect will be more intense—or less—when they land?
First, there is the slope of the shoreline. Obviously, if the shoreline is sloped, wave energy will land at a single point, whereas if the energy touches the shoreline over a long distance, there will be less impact.
Then there's the type of sediment. The wave will not have the same effect on sand or silt as on a rock wall.
There are also riparian buffer strips. The more natural vegetation there is, the better protected the shoreline and the soil will be, which will prevent erosion.
Finally, there is the impact of normal and prevailing winds. When we compare waves from boats, we want to compare them to the natural waves experienced by the lake. For example, there will be very few waves in some bays, compared to areas exposed to the prevailing wind, where the waves will be much stronger. We also have to include storm winds, which are stronger. During storms, there's much more wind, obviously. However, given their short duration, the effect of winds generated by storms is much less significant than the effect of the frequent waves produced by the high number of boats. We took storm winds into account in our study. On the other hand, if more extreme events occur due to climate change, there will obviously be more wind. That said, even if storms are more intense, they rarely last long enough to have a greater impact than the many boat crossings on a lake.
In conclusion, although the two lakes under study were very different, we recommended a similar restriction for vessel passage. In both cases, it requires a distance of 300 metres from shore for the waves arriving at the shore to be comparable in intensity to the natural waves on those lakes. I believe that this 300-metre restriction could apply to a number of other lakes, given that, despite the major difference between the two lakes under study, their shorelines were affected in much the same way by waves produced by wake boats.