Removal of Silt Accumulations Vital to the Health of the Lake
Lakewood, NY — Recently, the CLA completed a dredging project at the Crosswinds Marina in Dewittville. The project involved dredging out silt accumulations from the marina entrance channel and adjacent boat slip. The CLA has performed dredging work on Mud Creek in Mayville, at the mouth of Goose Creek in Ashville, and at the Rod & Gun canal in Lakewood.
Dredging is vital to sustaining the health and life of the lake and its surrounding waterways. The natural process of sedimentation occurs over time, and the accumulation of silt and other debris on the bottom of the waterways can cause a series of issues for the life of those waterways. We depend on our waterways for everything from transporting goods to fishing and recreation. Sedimentation can make it difficult to navigate those waterways, and sometimes can even pose an environmental hazard.
“One of the problems of the lake is too much silt gets into the lake from the creeks,” said Douglas Conroe, executive director of the CLA. “It often will deposit right at the mouth of the creek where it meets the lake. That forms a delta, and then the delta becomes a dam for the creek. So, when you have heavy storms the creek can flood because it can’t outflow. By dredging them out we are keeping that creek available for flow so flooding back upstream can be avoided.”
By dredging the waterbodies surrounding the lake, the CLA is also maintaining the health of the ecosystem. The sediment that travels into the lake from the creeks and rivers also contains nutrients, and having too many nutrients in the lake poses a problem for the health of the lake. By removing that silt, dredging also removes a source of those nutrients and helping to not add any additional nutrients to the lake.
“When the silt is disturbed by wave action the lake becomes roily,” Conroe said. “The phosphorous nutrients that are inside then get released into the water column. By dredging you are helping not to add additional nutrients to the lake.”
The machine used to dredge is a small barge boat that is equipped with a submersible pump and cutterhead. It has an arm that goes down under water and scoops the area to be dredged much the same way a backhoe would dig in the field.
“We have a special water vessel that looks like a harvester, although instead of having a harvesting cutting head it has a bucket head feature,” Conroe said. “It’s excellent to get in and remove what we call the spoils. The areas that need dredging are often used for navigation for boats going in and out of docks. What we are doing is digging out the entrance that filled over time with an accumulation of silt so that they can continue to traverse the channel and moor their boat.”
Maintaining the health of the lake is an ongoing process. Dredging where incoming waterways meet the lake is one part of that process. Dredging is critical for removing unwanted accumulated sediment, cleaning up the additional unwanted nutrients that make their way into the lake, preserving aquatic life and a healthier aquatic ecosystem, and preventing flooding of creeks and rivers leading into the lake.
“The public should know that we are doing these kinds of things to help the lake users. There are projects waiting and we will work with people if the funding can be found,” Conroe said. “It needs to be an ongoing effort. Funding is generally not there for it, so we do it as funding develops. It’s something that should be done to the creek bed on a rotational basis every five years. It’s an important service to be able to provide, especially when it comes to flood control. Every township is required to have a flood management program, and this should be part of that.”
“But, there’s a lot to do and there’s a long way to go,” Conroe said. “And in the meantime the silt keeps coming down from the creeks and depositing into the lake.”
Dredging is a component on the CLA’s strategy of performing adaptive lake management. The CLA has adapted the harvesting and shoreline programs this year to start earlier than usual. The harvesting removes tons of nutrient-laden nuisance plants from the lake. “By adapting our nutrient-removal program to remove silt, we are removing more overabundant nutrients from the lake,” Conroe said. “By removing the silt, we are removing a plant bed source which then becomes part of our integrated pest management program for plant control.”