Columbia Association (CA) is developing a lake and pond management plan that will bring a more proactive approach to dealing with sediment once it is in Columbia’s lakes and ponds. In future years, the plan would also address other issues such as water quality, vegetation and wildlife.
“If you don’t manage the sediment, you reduce the aquatic habitat and the aesthetic value of CA’s lakes and large ponds,” said Dennis Mattey, CA’s director of construction.
The plan would include the use of bathymetric surveys that measure the topography at the bottom of the lakes and provide information on how much sediment has accumulated. These surveys would lead to a timeline for regular maintenance of the lakes. The survey data would also help CA staff know when enough sediment has accumulated that it is time to remove it — and before the sediment has built up to the point that it becomes overly expensive to remove.
“It’s possible to do intermediate and small dredging operations when the sediment has accumulated at the upper end of a lake or creek,” Mattey said. “That will allow us to push major dredging efforts out a bit, all while maintaining the appearance of the lakes and saving money on dredging.”
Dredging was completed in early February at Lake Elkhorn, the last of Columbia’s three man-made lakes to have sediment removed over the past few years. This new lake and pond management plan would allow for sediment to be removed before it can again build up to a similar extent.
A draft of the Lake and Pond Management Plan is expected to be developed before the end of April. In future years, the final Lake and Pond Management Plan will tie the management of sediment, water quality and vegetation in the lakes to Columbia’s Watershed Management Plan, which is being implemented to improve water quality in the streams feeding the lakes and to reduce the amount of sediment being carried by our streams to the lakes and ponds.