By nature’s calendar, the life span of a lake is short. From the moment a lake is created, natural forces are conspiring for its eventual extinction. Plant matter, debris, sediment runoff, and even animal remains all contribute to lake fill-in. In entirely natural conditions, fill-in is part of the process of succession, by which nature works to restore itself to its most stable state; thus, lakes become wetlands, wet meadows, and eventually forests. It’s a long, slow process — the full cycle of succession can take more than a thousand years — that is decelerated by lake maintenance.
Nature’s timetable may be accelerated, however, by sediment deposition from upstream land-disturbing activities in a lake’s watershed. This is a common problem in areas with a high volume of construction activity, particularly if that activity is accompanied by inadequate erosion and sediment control practices. In addition to shrinking the size of the lake, excessive sediment impacts can contribute to problems with water quality and nuisance vegetation. When a lake has been significantly impacted by sediment, dredging operations may be required to mitigate the impacts and maintain the lake in a desirable condition.
There are a variety of dredging methods available; the best method for a particular lake will depend on the lake conditions and owner preferences. For lakes located in urban watersheds, the need for dredging will almost inevitably arise at some point — and perhaps may even come up on a recurring basis. Dredging can be costly, and too often lake owners don’t budget for it. Lake owners and managers considering dredging should expect to pay $10-30 per cubic yard of sediment removed, and be prepared to address issues regarding heavy equipment access and disposal of the removed sediment.
You can’t fight Mother Nature, but you can be aware of the conditions in your lake, and be an advocate for good erosion and sediment control practices in your watershed.
