Making Waves
Editor’s Note: Last fall, LAKE VIEWS published a Letter to the Editor on the topic of wake boats. Back then, the Editor noted there is ‘ongoing research’ and advised readers to watch for more information in Spring ’24. This is that information. This article contains several statistics, all of which came from a compilation of scientific research reviewed last year by the Michigan Department of Natural Resources. Readers wishing to see specific research are directed to the website listed at the end of this article for particulars. Photos in this article courtesy of Lakes at Stake Wisconsin.
Waves. They’ve been a part of Lake Beulah since the glaciers melted thousands of years ago. For most of time, waves were the result of wind, but in the last 100 years, motor boats have also made waves on the lake. Mostly, if they were thought about at all, boat waves were considered to be just a nuisance part of lake living, but recent water sport innovations have found a way to harness them for fun.
At first, wave enthusiasts found they were great for jumping with a jet ski, or flying over on a tube or kneeboard. And while the boat waves were a nuisance at times, lake folks tolerated them as a part of the fun of being on the water. But a few years ago a new and even more fun pastime was invented which allowed someone to literally ride the top of a wave trailing behind a boat. It looks like so much fun!
Unfortunately, what started out with the promise of being a really cool, new way to enjoy being out on the water, the technology of creating immense, ocean-like waves for wake surfing turns out to have strings attached. On lakes like Beulah around the country, there is a growing sense of need for risk management to mitigate unforeseen consequences. An article in the April 2nd Milwaukee Journal Sentinel points to wake boating emerging “as a hot button issue in natural resource and recreational management.”
“Of course, like all things, there are differences of opinion when it comes to the impact of wake-boat sports. That’s why Lake Beulah is so fortunate to have the Collaborative Stewardship Initiative (CSI) process underway through the Institute for Systems Change & Peacebuilding at UWM. There is great hope that the CSI will help inform all who care about the lake, and steer leaders to make important decisions on its future.”
The intent of this article is to inform readers on the impact of wake boats generally. Naturally, there are other opinions, among them that wake boats ared not the problem at all, it’s the boat drivers. Whatever the cause, the article in the
Milwaukee Journal Sentinel notes “wake-enhanced boating is causing far more conflicts and concerns than any other type of water sport that’s come on the scene in the last half-century.”
Let’s take a look at what’s been happening.
Direct observation, as well as a growing body of academic research, both point to the new technology of creating extremely large waves as having unintended, deleterious effects to Lake Beulah. These negative effects result from both the waves themselves and the tremendous power required by boat propellers to generate them.
WAVE ENERGY
Interestingly, waves don’t really move much horizontally across the lake. Rather, it is the energy of a wave that is transmitted through the water as the wave moves. This energy, directed both outward and downward, is a major problem of wake boat waves. Here is some recent scientific research.
• Wake boats can produce waves with 17 times the energy of other comparable-sized powerboats.
• Wake boat waves can take 1,023 feet to dissipate to heights and wave energies observed 100–200 feet away from ordinary boats.
• The US Army Corps of Engineers says the energy in a boat wake goes up exponentially with wave height. Waves produced by a wake boat can have 581% more energy than waves produced by the same vessel operated in cruising mode at a distance of 100 feet.
• It would take 950 feet for waves from a wake boat in surf mode to decrease to the 0.8-foot wave height typically observed 100 feet from the same wake boat operated out of surf mode.
• Waves produced by wake boats were 2–3 times higher, had 3–9 times more energy, and were 6–12 times more powerful than a typical motorboat.
• When wake boats passed 100 feet from shore, the wave energy produced was 2,546% higher, than the monthly maximum energy from wind-driven waves
PROPELLER WASH
To push a boat forward, the propeller must push against the water. As it does so, it pushes the water out behind. This fast moving water behind the propeller is called ‘wash’.
• Wake boat propellers were determined to be able to generate enough turbulence to stir up bottom sediments in water up to 33 feet deep.
Why are these statistics important? The overall topography of Lake Beulah, and especially portions like the Upper lake, are long and narrow. Because they are so large and have so much energy, wake boat waves don’t sufficiently dissipate before reaching the shore.
As for propeller wash, even the most experienced Lake Beulah boaters will admit it is difficult to precisely know when the lake bottom rises up. Lots of power boats can cause damage to the lake bottom, but the depth of ‘wash’ from a wake boat is especially challenging to manage.
IMPACT ON WATER CLEANLINESS AND THE NATURAL ENVIRONMENT
Already, the cumulative negative effects of wake boats on Lake Beulah have lead to loss of habitat, resulting in the decline of aquatic ecosystems and fishing.
• Fish Spawning - When a wave hits the shore, it curls under to the bottom, scouring the lake bed. Bass and panfish nest in 1-3 feet of water. Wave jostling of spawning beds causes their destruction. In just the last few years, and in direct correlation with the appearance of wake boats on Lake Beulah, there has been readily observed loss of fish spawning beds around the lake.
• Erosion - Wake boats operating in surf mode create larger wakes than traditional watercraft. The greater energy of these waves is likely to exacerbate boat wave induced shoreline erosion. To combat this, some around the lake have reinforced their shoreline. Unfortunately, this in turn causes greater scouring of the lake bed.
• Sediment Resuspension - More than any other kind of boat, through increased wave energy and propeller turbulence, wake boats have greater potential to exacerbate nutrient suspension and decrease water clarity.
• This stirring up of bottom sediments is an oftentimes ignored concern as it can greatly disrupt lake chemistry. The muck lake bottom holds undesirable substances, including phosphorous, a prime stimulant of algae production.
• The result is a subsequent reduction in the ability of fish to find food, a decrease in the depth to which aquatic plants can grow, and a lowering of dissolved oxygen content within the water column.
• One recent study on a 1,100 acre lake compared the waves produced by wake boats operating at 10mph when in wake-surfing mode with waves from the same boats when in non-wake producing mode. Researchers determined wake surfing waves would require 675 feet greater distance to produce sediment resuspension equivalent to that in normal operation.
IMPACT ON OTHER LAKE ACTIVITIES
A growing group of lake people are increasingly alarmed at the impact of wake boat generated waves on their enjoyment of the lake. Those having smaller craft, canoes, kayaks, fishing, sailboats, pontoon and even ski boats are complaining wake boats are greatly interfering with their activity. Many talk about being swamped or almost so, to the point they are choosing to stay off the lake when wake boats are active.
LAKE BEULAH AT A CROSSROADS?
All this fuss over wake boats is pointing to Lake Beulah being at a crossroads of sorts. As more and more folks are realizing the fun they could have, more and more wake boats are being purchased. And, not just by lake residents.
Is Lake Beulah becoming a ‘destination lake’ for wake boat sports? One Saturday last summer, 16 of the public launch boat parking places were taken up by wake boat rigs. And that increase in wake boats has lead to research pointing to the problematic nature of large waves being significantly compounded by the presence of other large waves.
Then, with its sometimes narrow shorelines, irregular depth, and muck lake bottom, we’ve got to ask ourselves how our lake activities may be negatively impacting the lake ecosystem. While Lake Beulah can’t talk, it certainly appears she is increasingly letting us know she is being forced to change.
At any rate, both direct observation, as well as scientific researchpoint to no good result. As stewards of the lake, we’ve got to ask ourselves what we want, and what is best for Lake Beulah. What do you think? LakeBeulah.LakeViews.Editor@gmail.com
For more information: A Literature Review of Wake Boat Effects on Aquatic Habitat, State of Michigan, Department of Natural Resources, July 2023 https://mymlsa.org/wpcontent/uploads/2023/07/Fisheries-Report-37-Wake-Boat-Study-Official-Version-Released-on-7.28.2023.pdf