Dredging Defined

What Is Meant By Dredging?

Dredging is basically the removal of sediment and other material from a lake or pond and there are two basic types. “Dry dredging” is a process of draining the lake completely and using heavy machinery to remove the sediment and gravel. “Wet dredging” removes the material while it’s still under water, using a barge and vacuum pumping system, allowing the lake to still be partially used. Either way you get there, dredging has its benefits and detriments.

Benefits:

  • Increasing the depth of shallow lakes has long-term advantages. Adequate depth promotes fish growth, discourages weed growth, lowers water temperatures, increased oxygen levels, and recreational boating opportunities.
  • Dredging can effectively remove plants, organic matter and nutrients. The removal of nutrients and sediment will reduce the internal nutrient loading, and help to discourage further growth of some types of algae and weeds.
  • dredging can be site specific and directed at target areas.

Detriments:

  • cost
  • depending on the method used, you may temporarily displace or kill some of the living organisms including fish and bethnics.
  • portions of the use of the lake for human activities are precluded during dredging.
  • disposal of the dredged spoils is costly and may pose environmental impacts.
  • dredging should not be viewed as a viable method for managing aquatic weed and algae growth. Only about 10% of the ponds that have been dredged in New England for the purpose of managing plant growth have effective management for more than two years. Most lakes experience a regrowth of aquatic vegetation quite readily after dredging.
  • because dredging does nothing for the nutrient overload being imposed on the lake by its residents, high concentrations of algae is a post-dredging problem.

As with any lake management technique or project, there are advantages and disadvantages to consider.

Effective lake managers must focus on the results and not the activities.

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