Mar 02 2016

Let’s Talk About Dredging

Natural scenic beauty and erosion control are components of the State’s shoreline protection program. Riparian landowners accomplish these goals by allowing native vegetation to overtake the shore yards, slowing runoff of pollutants toward the waterbody and masking human habitation.

Each year, surrounding vegetation sheds leaves, needles and summer growth.  Much of this vegetative matter enters our waterbodies, decays into various nutrients, and speeds the process of eutrophication, or aging of the lake. Decayed organic material is a major component of an algae bloom.  Over the years a dense layer of this decaying vegetation has made many of our lakes un-fishable, un-swimmable or just unfriendly.  Un-fishable begins when there is no natural reproduction of desirable fish as their spawning beds are mucked over. Un-swimmable means the muck is so deep in many places you are not swimming in water but in muck. Unfriendly is when landowners must place piers farther and further out to use their boats.  As the quality of lake activity diminishes, so does the value of our lake homes.

Unfortunately, whenever the word “dredging” comes up in a conversation, everyone involved in that dialogue speaks from personal experience or whatever exposure they might have had to the practice.  For many in Wisconsin the dredging of the Fox River comes immediately to mind. This massive undertaking, costing untold millions of dollars and involving some of the most complicated mechanical techniques to remove a laundry list of toxins, is the only knowledge many landowners have of dredging.

When riparian owners consider dredging, it should not be likened to the Fox River operations.  Very small, low volume pumps are involved.  No lake bed is removed in these operations as screened hoses only allow the finest of materials to be evacuated.  There is more control of material removal on a smaller scale than with larger operations.  Municipalities have a reasonably good idea if the area has a history of contaminated sediment and where the contamination came from.  Preliminary muck samples from northern lakes are showing, so far, at the highest, 48 pounds per ton of nitrogen and 2.18 pounds of phosphorus per ton.  The estimated nutrient value was $13.99 per ton.  Many more samples are planned for a better picture of what this decayed material is composed of.

We challenge you, as a riparian owner concerned about the advancing eutrophication of your lake, to collect samples, dry them and have them analyzed.  You can use the same services as dairy farmers use for manure or cities use for compost testing. It’s fast and economical.  Find out what is really down there, is it eroding soil or is it decayed organic matter?  Then contact your lake association and get to addressing the real problem.