As the world has grown more aware of personal and corporate environmental footprints, here at Aquascape we’ve received a growing number of requests for “green” and/or “natural” methods of algae and aquatic weed control. There’s no all-natural magic bullet to solve the problem of unwanted aquatic growth in a hot Georgia summer, but there are non-herbicidal options that can be incorporated into a comprehensive lake or pond management plan.
Grass Carp
Stocking of sterile Grass Carp is a viable option for control of certain submersed aquatic weeds (in Georgia, only sterile grass carp obtained from state-licensed dealers may be legally stocked for biological weed control). Grass carp are most effective at controlling submersed aquatic plants. While not a cure-all — they show a feeding preference for some plants over others and don’t address all conditions that can lead to algae blooms and other issues — grass carp can be a cost-effective long-term component of an overall management program.
Aeration
Aeration, which is the mechanical circulation of oxygen in a lake, increases the dissolved oxygen content and the level of bacteria activity within the water column. More active bacteria consume excess nutrients, helping to improve water quality. Aeration can also reduce lake stratification, enhance fish habitat and help prevent fish kills. However, while an aeration system can be a great addition to an overall lake maintenance program, it isn’t a “lake manager in a box,” and isn’t suitable for every lake. And although an aeration system can reduce the need for herbicide use, it isn’t strictly “green,” since it requires electrical power! Still, it’s an option worth considering for some lakes.
Bioaugmentation
Bioaugmentation (aka biological augmentation) refers to the use of microbial and enzyme products to metabolize excess nutrients and break down organic matter in the water. Organic “sludge” (decaying debris and organisms) builds up over time and negatively impacts water quality by giving algae a food source; bioaugmentation products can slow down the build-up process and help to improve water quality.
Vegetated Buffers
A vegetated buffer is simply an area directly adjacent to a water body in which plants (preferably native) are installed and allowed to flourish. A buffer may include a variety of aquatic, herbaceous, shrub and tree species, and offers an appealing natural look. The water body benefits from a reduction of runoff; and a potential reduction in algae blooms, as excess nutrients from runoff often contribute to the conditions under which blooms occur; a reduction in shoreline and bank erosion; and improved wildlife and fish habitat.
Education
Residents should be asked never to dump or blow grass clippings, leaves or any other yard waste into neighborhood lakes, as such seemingly “organic” debris contains nitrogen and phosphorus (nutrients that can that stimulate algae growth) and consumes oxygen from the water as it decomposes. Property owners living directly on a lake or pond should be encouraged to install vegetated buffers along their shoreline, or at least to leave a 10-foot strip of unmanaged grass and natural vegetation rather than mowing to the edge of the water.
