Lake Restoration Versus Lake Management?
A complex and potentially controversial topic that can mean various things to different lake user groups. Lake restoration often connotates attempting to return a lake to an original or previous condition – usually with a desire for clearer water (less algae) and fewer vascular plants, by the recreational user.
Management, on the other hand, typically refers to action(s) taken to produce a desired condition. Once the ecological balance has been altered, either through human intervention or acts of nature, the lake system can never truly be “restored” but only “managed.” Prudent “management” of our valuable pond/lake resources is a shared responsibility between the lake user/owner, professional lake managers and the regulatory community.
Dredging Not Always a Solution to Lake Problems
Dredging is often an appropriate lake management technique to provide added water depth and volume and potentially remove nutrient reserves that continue to support nuisance vascular plants and algae. In some situations, dredging will also reduce the abundance of rooted aquatic plants, primarily through limitation of light penetration and to a lesser extent by changes in bottom substrate.
During the 1970’s and 80’s USEPA and state agencies funded a number of New England dredging projects, each to the tune of several hundred thousand dollars or more. Specific dredging projects that come to mind include: Nuttings Lake (Billerica, MA), Morses Pond (Wellesley, MA) and 1860 Reservoir (Wethersfield, CT). A primary goal in dredging all of these waterbodies was to provide long-term control of nuisance rooted vegetation and/or algae. Within roughly 1-2 years from completion of dredging, however, these same lake communities experienced severe nuisance weed/algae conditions.
At Morses Pond, there is a reason to believe the pond dredging actually spread the plant (milfoil) infestation. What went wrong with these projects? To some extent, the potential benefits of dredging were “oversold” by the project proponents particularly in light of the limits imposed by funding and disposal options. Seldom will dredging alone, control invasive plants like milfoil through changes in bottom substrate.