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Why you should slow down in no-wake zones

By: Eric Sparks / Published: May 04,  2017

With peak boating season creeping up on us, I would like to focus this staff blog on the importance of no-wake zones.

A “wake” is the waves created as a vessel travels through the water. A “no-wake zone” is an area where vessels are expected to travel at slow (idle) speeds to minimize the wake.

Most people think of no-wake zones as the speed bumps or school zones of the water, and rightfully so. Public safety is often the primary reason for establishing and enforcing no-wake areas, and that is why most no-wake zones are near boat launches, docks or residential areas. While public safety is the reason many of these zones are established, the reduction of wakes in these areas also has benefits for the waterfront property owners and the environment.

Credit: Perry Chao/Flickr/http://bit.ly/2qJuAQ6 (click photo for link)
Credit: Perry Chao/Flickr/http://bit.ly/2qJuAQ6 (click photo for link)

Waterfront property owners directly benefit from the establishment of no-wake zones in their area from decreased wave energy hitting their shoreline. The consistent hammering of boat wakes will lead to erosion through wearing away at a bulkhead or washing away sediment from unprotected shorelines.

The presence of bulkheads or seawalls alone increases the overall energy, and subsequent erosion, along a shoreline by not allowing waves to dissipate (i.e., waves bounce off the walls of the flat bulkhead and “ping-pong” around the water body). This problem is exacerbated by large and frequent wakes. A good analogy is to think of a bulkheaded water body as a bathtub. When you push water into the wall of a tub, it bounces back forcefully. Whereas, a wave hitting a gently sloped surface (e.g., a natural shoreline) dissipates.

In fact, many waterfront property owners must install some type of shoreline protection to save their property from being eroded by boat wakes. The chosen shoreline protection method is often a bulkhead or seawall, which temporarily helps with their erosion, but increases the erosion potential (i.e., waves bouncing around) at the surrounding properties. An alternative suite of shoreline protection options is collectively called “living shorelines.” These projects help dissipate wave energy while also protecting shorelines and the natural benefits they provide. (Find more information about living shorelines projects.)

Have you ever noticed that the natural shorelines around no-wake zones often look much healthier, with more vegetation, than in areas with fast and frequent boat traffic? The reason for this is wave energy in those areas is much closer to the natural wave energy that shoreline has adapted to withstand. These observations are the basis behind why many no-wake zones are also established in environmentally sensitive areas, such as fringing marsh and intertidal oyster beds.

Coastal wetlands formed because they were in areas with relatively low wave energy and slow-moving water. The slower the water moves, the finer the sediment you find. This observation is why sand beaches have crashing waves and muddy, mucky bayous have calm water. With more vessel traffic and wakes in coastal wetlands, we can expect substantial amounts of erosion because those areas aren’t adapted to high wave energy. It’s much easier to wash away muddy sediment than sand. As coastal wetlands wash away, the natural benefits they provide goes with them. Coastal wetlands are imperative to supporting seafood production, maintaining good water quality and protecting our developed coasts from storms.

As you can see, there are many reasons why no-wake zones are important. Even though these areas seem like they slow you down, I would encourage you to sit back, relax and enjoy the scenery as you pass through these areas. Observing the differences in shoreline characteristics caused by wakes will emphasize the importance of these areas to maintaining our prosperous coastlines.

Any questions, call me at 228-546-1025 or e-mail me (Eric Sparks, an assistant professor with the Mississippi State Uuniversity Extension Service and coastal ecology specialist with the Mississippi-Alabama Sea Grant Consortium).

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