Making Waves: Boating Tips to Keep our Lakes Blue
November 19, 2018 -
LEA Summer 2018 Newsletter-Staff Writer, Summer 2018: NAPLES- Like everything else, recreational boating has evolved much over the years. Power boats have grown in size and average horsepower has increased greatly. At the same time, cleaner, quieter four-strokes have been replacing the smoky two-stroke outboards used to ply our water.
One recent trend has been the growth of wake surfing. This sport involves driving at low speed in a boat that creates a large enough standing wave to surf on continuously without being pulled by a rope. While this is an amazing sport, just like other boating activities, there can be negative impacts if it is done without regard to the environment.
One of the environmental issues with boating, whether for wake surfing or not, is the turbulence caused by propulsion, particularly from propellers. Past studies have shown that this disturbance can go down at least 10 feet. This allows previously settled sediments and nutrients to be re-suspended into the water column, clouding up the water and providing a source of nutrients for algae. Wake boats often take on water ballast which allows them to sit lower and create bigger waves. This means that these boats can generate turbulence deeper into the water column and their props pose an increased risk of chopping up and spreading both native and invasive plants. Another common complaint is that the large waves created by these boats crash upon the shore and erode the bank, Finally, and often overlooked, is the fact that lake water used for ballast is creating a new vector for spreading noxious invaders like Zebra and Quagga Mussels or the Spiny Water Flea. The young of these species are nearly invisible to the naked eye and can remain alive for weeks in ballast tanks even after the water has been emptied.
A simple and effective way to minimize sediment resuspension from boat propellers and reduce shoreline erosion is to observe the existing no-wake rule within 200 feet of shore. In most cases, this will put you into deep enough water. However, on lakes with extensive shallow areas, a good depth map is also needed. Staying out of shallow areas also greatly reduces the chance of spreading invasive aquatic plants within the lake and from waterbody to waterbody. Using the new depth data that we are acquiring with volunteer surveyors, LEA hopes to produce maps that clearly show deep water areas more suitable to power boating.
Preventing invasives from hitching a ride in ballast tanks requires completely draining these systems and sterilizing them before moving from one water body to another. Because these systems are becoming more commonplace, LEA and the State of Maine have adopted the new boat inspection motto, "Clean, Drain, Dry" and are asking Courtesy Boat Inspectors to inquire about ballast tanks when doing routine checks.
Lakes: Back Pond
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