*Costs are averages determined from data obtained from "Draft Generic Environmental Impact Report" for Massachusetts, and from
Aquatic Control Technology, Inc. Fact Sheet.
| Action |
Effectiveness |
Specificity to Target |
Advantages |
Disadvantages |
Cost* |
|
Hand Pulling
(Physical) |
Removes a few individual plants at time |
High |
Good for localized areas/ few plants
Plants physically removed from waterbody |
Labor intensive
Good for small infestations only. Not practical when plant
growth is dense |
Labor Costs vary depending upon contractor costs or staff time |
| Mechanical Harvesting
(Physical) |
Removes large amounts of vegetation at a time |
Not specific |
Rapidly removes vegetation from area
Plants physically removed from waterbody |
Fragments plants which could cause regrowth
Removes beneficial native vegetation.
Could increase turbidity, ultimately affecting other aquatic life
Does not remove rooting systems |
Ranges widely depending on plant density, location, disposal, etc.
Generally $350-$1500 per acre |
| Hydro-raking
(Physical) |
Removes large amounts of vegetation at a time |
Not specific |
Rapidly removes vegetation
Removes rooting systems to prevent rapid regrowth.
Plants removed from waterbody |
Fragments plants
Could increase turbidity, ultimately affecting other aquatic life
Removes beneficial native vegetation |
Ranges widely depending on plant density, location, disposal.
Generally $350-$2500 per acre |
| Benthic Barrier
permeable
non-permeable
(Physical) |
Used for very small infestations |
Specific to area where barrier is located
Impacts all plants under barrier |
Compresses plants to sediments and prevents likelihood of fragmentation by wind, wave, or anthropogenic means
|
Labor intensive
Must frequently be cleaned/re-staked
Plants not physically removed from waterbody
May cause sediment/water anoxia
May impact non-target species such as fish, invertebrates, and others |
$0.60-$1.22 per square foot
or
($25,000-$50,000 per acre) |
| Chemical Treatment |
Herbicides which are taken up by root systems (systemic herbicides) more effective than contact herbicides
|
Most chemicals have target species for which they are most effective
Varying application rates can increase target specificity |
Chemical has potential to eliminate exotic plant infestation if done at correct time, and if correct concentration is used
Relatively rapid effect
Longer time span of control than other types of control techniques |
Addition of chemical to waterbody
May impact non-target species if not applied according to label restrictions
Could be environmentally damaging if not applied per label restrictions
|
Varies with chemical and size of treatment area
Could range from $200-$1000 per acre. |
| Drawdown
(Habitat manipulation) |
Somewhat effective if repeated frequently
More effective if drawdown maintained for long time period |
Not specific |
Could control density of vegetation due to plant die off from dessication or freezing
Winter drawdowns favorable |
Impacts non-target plants
Impacts fish, amphibians, insects, and other aquatic organisms
Devastating to entire waterbody ecology |
Low cost if dam or other means of drawing
down water is available |
| Dredging
(Habitat manipulation) |
Effective in removing plants from localized area where dredge takes place |
Not specific |
Completely removes plant material
Removes nutrient laden sediments
Removes seed bank
|
Devastating to entire system.
Impacts non-target plants and animals
Could cause excessive turbidity
Must wait for waterbody to be filled again |
$16,000-32,000 per acre
Previously used and successful in one lake in New Hampshire (Milville Lake) |
| Biological Controls |
Effective against target plants |
Specific |
Insects, bacteria, or viruses used in this method are typically specific to target plant. Their life cycles revolve around particular plant species
Does not affect other non-target species |
May cause decline in oxygen as plant material decays
Many biological controls are themselves exotic
Still experimental |
Cost of insects
Monitoring cost high |
