When humans are faced with a problem, they
will find a "solution" for resolving "their" problem.
A homeowner looking at aquatic plant growths along his or her property might seek to remove
the plants independently or seek the services of an aquatic plant management company or state
agency to remove the plants. How the plants are removed may or may not become an issue as
long as the plants are removed. Unfortunately, such independent action may impact, either real or
perceived, other users of the waterbody, which leads to conflict.
Why should conflict arise? Conflict occurs because different individuals or different management
agencies place different values on the various attributes that attract people to lakes (Table 1).
Some value water clarity whereas others may be focusing on fish or aquatic birds. More
importantly, the history of human kind strongly suggests that each individual or group of
individuals believes there is a "right way," a "wrong way" and "my way!"
Conflicts or differences of opinion regarding what makes a quality lake can be dealt with more
effectively if every waterbody had an aquatic plant management plan. The plan at an individual
waterbody, however, should reflect not only the desires of the user-groups, but how lakes and
reservoirs actually function. Because lakes and reservoirs are complex systems and users often
have different desires, putting exactly the right plan into action is a process of negotiation and
compromise.
What's the best way to manage aquatic plants? Herbicides, harvesters, grass
carp, dyes, screens,
drawdown and many others are all viable options. But the difference between success and
failure, between attacking or controlling plants, rests on a sound integrated aquatic plant
management plan. Such a plan can guide lake use, save time and money, identify problems, and
reduce unwanted environmental changes as well as neighbor to neighbor conflict.
Without a plan, management objectives remain undefined, leaving no way to gauge progress.
Treatments can become haphazard in multi-use waters. Plant communities might be removed or
damaged that did not need management or control, wasting time and money. Worse yet, failure
occurs in the eyes of the public because objectives seem to keep changing from year to year.
A successful integrated aquatic plant management plan is built on six main
principles: (1) identify
the uses of the water body and determine if any of
these uses are impaired or benefited
by aquatic vegetation (define the problems, Chapter 4);
(2) understand plant ecology and the
ecology of the water body (Chapter 3);
(3) set
management goals;
(4) consider all
management techniques (Chapter 5) and select for use those that
are most appropriate for the
defined problems;
(5) develop an action plan and a program to monitor
the success or failure of
management activities;
(6) establish a long-term aquatic plant
management education
program.
Getting Started
Step 1 - Organization is key
You are probably reading this manual because you are concerned about an aquatic plant problem
in your favorite lake or reservoir. The first step in managing aquatic plants is to get
organized!
Many lakes already have a home owners group or lake association so much of the organization
and infra structure is already in place.
Some water bodies are privately owned, and a few are managed by corporations with clear levels
of authority and designated decision makers. Most are not! Even the legal corporations formed
by a group of property owners are absolute democracies at heart, no matter what the
organizational chart looks like on paper. Begin by talking with your neighbors or other
concerned parties to determine if they have shared concerns about the water body.
Managing a lake or reservoir usually also implies managing a group of interested citizens as
well!
Step 2 - The steering committee
If there is a consensus that a problem exists, a small (3 to 10 people) steering committee
should
be formed to begin the process of developing an integrated aquatic plant management
plan. In
establishing the committee, membership should represent the larger user community. The
committee must achieve community acceptance if a workable plan is ever to be developed and
implemented.
The steering committee will be responsible for completing the steps in developing an integrated
aquatic plant management plan. Developing a plan will be time-consuming and involve
considerable discussion of different points of view. The steering committee should therefore be
headed by one or two individuals, who have the respect of other members and the skills
necessary to conduct orderly meetings. These individuals should also have the temperament
necessary to assist in the resolution of conflict.
Once established, it will be critical for the steering committee to remain in touch with the
community to share information and allow for participation of all interested individuals in the
planning process. This contact can occur through direct contact with individuals and
organizations, newsletters, scheduled public meetings or articles in local or regional
newspapers.
Principles of an Integrated Aquatic Plant Management
Plan
Principle 1 - Identify the uses of the water body and determine
if any of these
uses are impaired or benefited by aquatic vegetation.
The first step to reaching consensus is defining the problem or problems. Make a list of users of
the water body. The steering committee itself may represent a variety of users and can start with
its own membership for ideas on who uses or has an interest in the water body.
It is important to try to identify everyone who has an interest in the water body and invite, as
soon as possible, representatives from the various user groups to participate. Do not overlook
developers, real estate brokers, and other business interests that may not seem to be directly
involved at the lake or reservoir. Ultimately, the development of the aquatic plant management
plan will involve politics so keep community, state, and federal elected representatives informed
and hopefully involved.
After you have a list of uses, find out what the users consider to be the problem(s). Different
users will have different points of view about the water body's problem. Begin with the
assumption that everyone's perceptions of the problem(s) have merit. Let everyone
participate!
Do not decide alone what you want to achieve and how! Small, dedicated groups of activists are
particularly likely to decide in isolation what problem should be cured and then are surprised
when the community later rejects their great plan. The best problem statement probably will
come through combining the perceptions of several user-groups.
Once a complete list of user problems has been elicited from the participants, group the problems
into categories. This task involves grouping problem descriptions according to what uses they
affect. Some uses of a water body that can be affected by excessive aquatic plant growth are
fishing, swimming, motorboat access/passage, visual enjoyment, and fish and wildlife habitat.
Take all the perceived problems and look for commonalties that link the problems. Shorten the
major categories into a brief description of the main problem(s).
You have now progressed from "the problem as perceived" to "the problem as defined," but you
must continue to refine the problem(s) statement. Understand that this is a necessary course for
consensus building. Always, state the problem accurately and precisely because, words have
meaning, but the meaning may be different for different users. For example, when anglers are
concerned about fish it is important to ask which fish, largemouth bass and bluegills or trout and
salmon. It is also important to ask if they are talking about the fish population or just the catching
of the fish.
After completing your problem statement, you will end up with something like
this:
Principle 2 - Understand plant ecology and the ecology of the
water body to be managed.
Plant and lake ecology are complex scientific subjects, but much of the general background
information needed to develop an integrated aquatic plant management plan is already available
(see Chapter 3). At this phase of plan development, it is important
to assemble as much site
specific information as you can. Even what seems to be the most insignificant piece of
information can help develop a successful aquatic plant management plan.
You probably know more about "your" lake than just about anyone else. You can easily describe
your lake in general terms: you know where the plants are thickest, where the snags are that can
snap your prop or tangle your fishing line, and where the big, hungry fish like to hang out. The
description of "your" lake that is required for a Plan is really no different from how you would
describe your lake to a friend. However, where your description to a friend might include
observations and information on how to avoid obstacles and where to catch fish, the observations
required for a Plan describe where aquatic plants are and what it is about the water body that can
affect the growth of plants.
Some of the information required includes:
Identifying what aquatic plant species are in a water body is critical for several reasons. First,
different species often respond differently to the same control techniques. A technique that is
very effective on one species may not work at all on a different species. Second, it is also
important to determine whether any rare or sensitive plants are present. These species may be
protected and some plant control techniques might be prohibited. Finally, it is crucial to find out
whether any invasive, non-native plant pests are present because the presence of these plants
often calls for fast, aggressive action.
Knowing where plants are located will assist in understanding where plants are causing weed
problems. This information combined with how many plants (percent bottom coverage or percent
of water volume occupied) are in the water body will greatly assist in determining what the
potential environmental effects of plant management may be. For example, the elimination of a
small area of plants around a swimming beach will not turn the water turbid with algae in the
whole-lake if the lake has a bottom coverage exceeding 50%. However, if a plant management
technique, like the use of grass carp, is chosen to remove all of the water body's plants, there is a
strong probability that water clarity will be reduced by the growth of suspended algae.
Depending on a water body's size, depth, and other characteristics, aquatic plant growth can be
extensive or extremely localized. An aquatic plant survey involves systematically traveling
around the water body, not just the shoreline, and noting aquatic plant conditions. An aquatic
plant survey can be conducted by volunteers, but it is wise to seek a little expert assistance.
Remember, an important part of the survey is collecting samples of aquatic plants in order to
identify the plants. Again, this is especially important if invasive, non-native macrophytes are
suspected to be present.
Aquatic plant surveys are usually conducted at critical stages in the growth cycle of plants.
Ideally, surveys should be performed early in the growth season (spring), at mid-season
(summer), and late in the growth season (fall). From a practical standpoint, most aquatic plant
surveys are limited to once a year because of time, personnel and/or financial limitations. If the
plant community can only be sampled once, it is recommended to try to conduct the survey when
plants are most obvious, which is usually at the height of the growth season (August). If the
survey can not be conducted at the peak of the growth season, do the survey when you can, some
information is better than no information.
Aquatic plant surveys can be simple or complex. If financial resources are limited, a simple
survey will often do quite well. A simple aquatic plant survey consists of identifying major types
of aquatic plants (emergent, floating-leaved, submersed, and freely floating, Chapter 3),
drawing a map of aquatic plant types and their locations in the water body, estimating relative
abundance of aquatic plant types, and collecting samples of plant species.
b) Water body usage map: A map showing
the locations of different
uses such as boat
launch sites, swimming beaches, drinking water intakes, fish spawning sites or aquatic bird
nesting areas should be constructed so that the map can be placed over the top of the aquatic
plant map. This will permit a rapid determination of where and what species of aquatic plants are
benefiting or impairing uses. Once this map is developed, it becomes possible to better determine
the scope of aquatic plant management needed in the individual lake and what plant management
techniques represent potential management tools. As this map is developed, it is important to
look for potential conflicts in use, such as establishing boat access in an area where fish
spawn.
c) Water chemistry and fish and wildlife
information: Many local, county,
state and
federal agencies routinely monitor water chemistry and fish and wildlife populations. Sometimes
a nearby college or university may have had students studying the water body. Although some
individuals do not view this type of information as being pertinent to removing the weed
problem, having available information can help assure that a bad management decision is not
made. More importantly, it can help build the confidence of skeptics that the individuals
involved in the development of the aquatic plant management plan are looking at all aspects of
the problem and are committed to making prudent decisions.
Knowing historical water chemistry and water clarity, can help determine if the lake or reservoir
has become enriched with nutrients or is responding to natural factors. For example, lakes and
reservoirs often develop clearer water during periods of droughts. Periods of clear water can
enhance the growth of plants and weed problems can develop. More importantly, information on
nutrient (total phosphorus and total nitrogen) and algal biomass as measured by chlorophyll
concentrations can provide a basis for predicting what might happen to the water body's water
clarity and algal levels with different levels of plant management.
Knowing what type of fish and wildlife is in the lake is critical because the abundance of specific
types of fish and wildlife is directly related to plant abundance. Controlling small amounts of
aquatic weeds will most likely have no effect on fish and wildlife. Even the total removal of
aquatic macrophytes does not "kill" a lake. Fish and wildlife will still be present, but the
abundance and types of fish and wildlife may not be what is desired by the community. Here it is
also crucial to define what is meant by various terms. Are you interested in the fish population or
are you interested in a specific fish such as the largemouth bass? When the discussion turns to
waterfowl does this term mean ducks and geese or all aquatic birds?
d) Water body - watershed connection:
Lakes and reservoirs are a
reflection of their
watershed. Although water bodies are dynamic systems, the nature of their watershed, however,
limits what can be done in the arena of aquatic plant management. For example, water bodies
located in fertile soils will support more plant life (abundance and variety) than water bodies in
non fertile soils. In fertile lakes, aquatic plant management is a long-term commitment whereas
in non-fertile waters a treatment may last for years.
Watershed maps help describe where the water body's water is coming from and going to. This
can be extremely important if a management technique such as the grass carp is being
considered. Grass carp can leave a water body with inflowing and outflowing streams unless
barricades are erected.
Nonpoint source pollution can also be a problem. For example, the delivery of large amounts of
sediments can cause a water body to become shallower and thereby support more aquatic
macrophytes. Increases in nonpoint sources of nutrients also can stimulate algal and aquatic plant
growth. Sometimes, the long-term solution requires correcting problems in the watershed.
Current maps and information on a water body's watershed are important, but do not overlook
historical maps and information. Newer is not always better! What people see today is often a
reflection of past human activities. For example, old aerial photographs available at a local
university or library may show that a lake used to support an abundance of aquatic macrophytes.
Other historical photos may also show that dredging was used to deepen the lake. Making a lake
deeper removes plants and can eliminate a weed problem. However, lakes fill in over time.
After a few decades, the lake can shallow sufficiently to permit aquatic macrophytes to once
again grow abundantly. If people using the lake came after the dredging operation they may
never know that their "naturally deep" lake with no weed problems was the work of humans.
Current and historical information (including maps) may be available through a variety of local,
county, state and federal agencies and libraries. Some places to look include your local soil and
water conservation service, national resource conservation service, agricultural extension service
office, highway department, fish and game or conservation department and local college or
university. Obtaining the information will require significant leg work, but it will be useful.
Finally, do not make the assumption that one agency or even one division within an agency
knows what the others are doing. Personally check with all agencies to ascertain if they are
working on some aspect of the lake or reservoir.
A written description of the aquatic plant map with overlying usage map in Lake
Tranquil might
read like this: "Aquatic plant growth in this lake is confined to a narrow band around most of the
shoreline, extending out to 12 feet in depth. Historical photos show that the area of aquatic plant
growth has changed little since 1965. The total area of the lake occupied by aquatic plants is
estimated to be about 40 acres (or 40% of the entire lake area). Some isolated patches of
emergent, plants such as iris, cattails, and other reeds and rushes occur along the shoreline. A
large water lily bed occupies the end of the lake where the swim beach is located. The submersed
plant community is composed of sparse stands of naiad, common elodea and small-leaf
pondweed in the shallows, and moderately dense beds of big-leaf pondweed occurring
throughout the deeper water areas. A large, surfacing stand of Eurasian milfoil also occurs near
the boat launch. In addition, a few scattered stands of milfoil plants are present at the opposite
end of the lake (near the swim beach). The milfoil is intermingled with the other submersed
plants and seems to have entered the lake around 1978.
Lake Tranquil currently supports a trout fishery that is maintained by stocking programs because
trout spawning sites in the lake are extremely limited. Largemouth bass and bluegill have been
the dominant fish since 1930 and are fished for by 55% of the anglers. Lake Tranquil also
supports a colony of nesting blue herons. Also, the wetland areas near the swim beach are
classified as a conservation area, and are recognized as beneficial zones and protected as part of
the overall state conservation management plan."
Once all uses, impairment of uses and the underlying ecology are understood, the next step is to
come up with specific management goals. Management goals define what the community wants
to achieve in response to the aquatic plant problem(s). Defining goals helps in selecting the best
management methods, which form the heart of the Plan.
It is important to understand the difference between management goals and management
methods. The goals are conditions in the water body that the community wants to achieve, and
the methods are the means of attaining those conditions. A goal, for example, might be to reduce
aquatic plant growth near a swimming beach so that it is no longer a safety hazard. Mechanical
harvesting of the plants, the use or herbicides, or stocking the lake with grass carp (fish that eat
plants) are all methods that can be used to achieve the goal. But, the method cannot be chosen
before the community establishes its goals and examines other critical aspects (for example,
legal, political, or financial limitations) of the problem.
Goal-setting begins by identifying an initial set of goals that is reasonable and realistic for the
community and the water body. These initial goals must address specific uses and be
attainable.
It may be useful early on to set specific criteria to aid in goal-making, such
as:
Give priority to keeping a particular area clear of weeds, especially where human safety is
at risk.
Limit community outlay to less than a specified dollar amount.
Reduce costs by using volunteer labor where possible.
In setting the management goals, there is one option that should always be considered: the do
nothing option. When a problem(s) arises, solutions are sought. As mentioned early, selecting a
control technique without firmly established management goals and then trying to sell it to the
community is a recipe for failure. Similarly, the community must know that doing nothing option
was considered and that the consequences were indeed worse than the course of action chosen. If
this option is not carefully considered, lingering doubts among groups of individuals may
adversely affect the ultimate adoption of an integrated aquatic plant management plan or any
future modifications of the plan.
Here is an example of management goals for Lake Tranquil:
Principle 4 - Consider all management
techniques
Chapter 5 provides a description of the primary aquatic plant
control alternatives currently
available. Each option's mode of action, effectiveness, duration of control, advantages,
drawbacks, and costs are discussed.
With so many techniques to choose from, how do you sort out the options? First, you'll have to
become familiar with the advantages and disadvantages of each control alternative. Management
techniques then need to be evaluated based on environmental, logistical, economic and legal
factors. Having a basic understanding of the capabilities of each option will help you choose the
best individual or combination of treatment methods for the water body of concern.
Aquatic plant management usually involves "doing something" in the water body to correct the
problem. Again, it is important to remember that for some members of the community the
control options may not be as appealing as simply "doing nothing". Consider the possible
consequences to the water body if no action is taken against problem aquatic plants. It is
particularly important to consider the possibilities, but you must deal with what is probable; else
no action will occur by default.
Another decision that has to be made, which will help determine the method of control, is the
intensity of control desired. This step involves determining how much control is needed for
particular plant problems. Are there plant zones around the lake that should be left alone (no
control)? Where should a low level of control be applied to preserve some intermediate level of
plant growth? And under what circumstances would a high level of control be necessary, such as
where a minimal amount of nuisance plants can be tolerated.
Remember that changes that take place in a water body following aquatic plant management
often
have little to do with the technique used to control the plants. It is the action of controlling a
certain quantity of plants that initiates the major environmental changes.
a) No Control: It may be best to leave special
habitat areas untouched, such as
shoreline wildlife
conservancy areas that serve as nesting and forage sites for waterfowl and other animals.
Sometimes these sanctuary areas are islands within the water body system. Native plant beds that
function as fish spawning sites might best be left alone or subjected to minimal treatment. In
some cases, the presence of native plants may have aesthetic value to the surrounding
community.
b) Low level of control: Low levels of control
might be all that is needed to
attain your
management goals. This usually involves a partial removal of vegetation or removal in select
areas. For instance, in lakes where a warm-water fishery is important, using mechanical means to
develop fish lanes through vegetation can be quite valuable. Low-intensity control efforts are
also important in shoreline treatments where emergent vegetation is to be protected. A benefit of
low-level control using mechanical means is the low treatment cost per acre because less plant
material is managed.
c) High level of control: Certain situations
may require aggressive control. For
safety reasons, it
may be necessary to clear all vegetation from swimming or wading areas. Other areas requiring
intensive removal may include areas around docks or boat ramps. The presence of invasive
non-native plants may justify aggressive whole-lake measures to remove plants. Lake-wide
control efforts to control 100% of the aquatic macrophytes are often not considered appropriate
by some user groups, but it might be the best alternative when invasive, non-native plants have
been identified.
To determine appropriate levels of plant control in your water body, refer to the water body
usage map and the aquatic plant map. The following tasks provide an example on how to use
these maps to produce a control intensity map.
On the usage map, identify use areas of the water body that are not impacted by existing aquatic
vegetation growth. Make a list of these use areas under the heading No Control. Next, locate
areas around the water body that are or have the potential to be designated conservancy zones or
confirmed endangered, rare, or sensitive plant populations. Add these areas to No Control list, if not already included. On the
usage map, identify use areas of the water body that require
some control of existing aquatic vegetation growth. Make a list of these use areas under the
headingLow Control. On the usage map,
identify use areas that require maximal removal of
aquatic plant growth. Make a list of these areas under the heading High Control. Referring
to the aquatic plant map, locate areas with invasive, non-native plant populations (like Eurasian
watermilfoil or hydrilla). Include these areas on the list of High Control if not already
identified.
The end product is a map clearly showing zones of all three control intensities. Construction of a
control intensity map will aid in choosing appropriate treatment options for each area of the lake.
Unless the objective of the management plan includes whole-lake, high control intensity, more
than one control technique is usually required.
Using the control intensity map, match each
control zone (no control, low control, high control)
with an appropriate control method. The following considerations are important:
Probable duration of control.
Site-specific constraints that might affect use of a control
method.
Program costs.
Human safety and health concerns.
Fisheries, wildlife status and general ecology of water
body.
Balancing enhancement of beneficial uses with environmental
protection.
Possible mitigation techniques and
costs.
Local, county, state or Federal permit
requirements.
II. First-year milfoil treatment: Systemic herbicide applications in boat launch embayment with
bottom barrier application in swimming areas (spring). Water lily treatment: Systemic herbicide
(Spring).
III. Second-year milfoil treatment: Diver hand removal/bottom barrier application on residual
populations (spring). Water lily treatment: Systemic herbicide/bottom barrier (Spring).
IV. Five-year watershed controls: Implement erosion control in the watershed to prevent the
shallowing of the lake near stormwater inputs. Control nonpoint source nutrient pollution to
minimize the potential for increased growths of algae."
The final task is to take all the information and formulate a written, long-term action program
(Plan) for aquatic plant management. The Plan should be flexible and evolving. There should be
short-term and long-term program elements. Remember, this Plan provides the community with
guidance and direction for aquatic plant management. A written Plan also provides continuity as
time moves on and active participants change!
The Plan should also provide for regular checking of how well the actions are working and allow
for modification as conditions change. The best time to plant a tree was 20 years ago and the next
best time is today. Lake monitoring programs are similar to planting trees, because if one was in
place 20 years ago you could already reap the benefits of historical information. This information
could reveal any significant changes that have occurred in a lake and may point to the causes of
those changes. Starting a lake monitoring program today, like many states nationwide are
currently doing with volunteer help (for example, New Hampshire, Vermont, Wisconsin, and
Florida), is a good way to ensure future generations will have information to base good lake
management decisions on.
Lake monitoring programs are especially important for evaluating any lake management
activities, including integrated aquatic plant management. Without monitoring a lake there is no
way of determining if the management activities are achieving the determined goals set in any
lake management plan. If the management activities are achieving the set goals then all is fine, if
not then there has to be a revaluation of the plan and changes made to the management
activity.
The planning process results in a written Plan that summarizes all the information that you have
gathered. The written document provides the basis for annual review of short-term and long-term
elements of the plan. It is recommended that a three ring binder with tabs for each planning step
be used to organize your planning document. In this way, any new information, monitoring
results and necessary changes in the program can be easily documented for future use.
Your plan should have the following written components:
While the integrated treatment scenario forms the heart of the action plan, there are other
activities that are also essential components of the management program. These include legal
preparations (obtaining required permits), developing funding strategies, and budgeting. The
amount of time needed to complete these components can vary widely, so look ahead and
remember persistence is needed!
Principle 6 - Establish a long-term aquatic plant management
education program
A truly successful aquatic plant management plan requires a long-term commitment to education.
Memories are short and once a problem is "solved" most people tend to forget it and move on to
something else. Most areas are also prone to new people moving in. Newcomers will not have
the same experiences as those who were there when there was a problem!
Once the plant problem is removed, it is generally only a matter of a few years before users begin
to question why activities such as the maintenance control of aquatic plants is still being done. If
people do not understand why something is being done, they could easily convince others to help
stop the activity. Far too often, the reoccurrence of aquatic weed problems is the direct result of
this type of situation.
It is critical that programs be conducted annually explaining the management plan to the
community. Having photographs and videos of the aquatic plant problems before management
can help people understand why action is being taken. More importantly, educational meetings
can be used to tell the community of users that the Plan is not carved in stone and that changes
can be made.
Change for the sake of change will not maintain a quality lake or reservoir. It will, however, be
helpful to conduct periodic surveys of the community to gain their impressions of effectiveness
of the program and determine if the needs and desires of the community have changed. It is
important to be patient, be realistic in your expectations, and keep the lines of communication
open!
"In 1985,
Eurasian watermilfoil was found in Lake Tranquil. In the following three years, milfoil spread
throughout the boat launch area of the 100-acre lake, forming dense shoreline stands out to 12
feet deep. In addition, dense stands of water lilies choke the swimming area at the opposite end
of the lake. Swimming, boating, fishing and other recreational uses have been severely impacted.
A special rowing tournament held annually since 1975 on the lake in mid-summer can no longer
be conducted due to surfacing plant growth. Cancellation of this event resulted in an estimated
loss of revenue of $55,000. In addition, angler use at Lake Tranquil has declined from 73,000
angler-hours in 1985 to less than 10,000 angler-hours in 1988."
a) Aquatic plant map: A good map of the
water body's aquatic plant
community is among
the most important pieces of information needed to develop an integrated aquatic plant
management plan. This map should show what types of plants are in the water body, where
plants are located, and how many plants (percent bottom coverage or percent of water volume
occupied) are in the water body. Aerial photographs and photographs at points around the lake
are also helpful for determining plant species and the extent of a problem.
Principle 3 - Set management goals
If an exotic weed (nonnative aquatic plant) is present, give highest priority to reducing its
growth or eradicating it.
Setting goals involves balancing user desires with the natural limitations of the water body and
the financial resources of the community. For example, if the community decides that their goal
is the removal of all aquatic vegetation in a clear water lake that is 90% covered with submersed
aquatic vegetation, the community should expect the water to become less clear due to increased
algal growth after the macrophytes are removed. If the community can not afford to do
mechanical harvesting or herbicides each year, grass carp might become the management
technique of choice because it is the most cost-effective control technique. If grass carp are
stocked at high enough numbers, the fish can keep most types of plants out of a lake for over 10
years.
"The
management goals are to
maintain recreational uses of the lake and fish and wildlife habitat. The lake currently supports
40 acres of aquatic plants (40% coverage). The management goal is to maintain between 10 and
20% cover. Where possible, milfoil will be removed, but when milfoil can not be removed its
growth will be managed. Growths of aquatic macrophytes will be eliminated from the public
swimming area and boat launches to insure safety. Riparian owners will be allowed to clear
shoreline vegetation up to 25 feet wide and to a depth of 8 feet. The community will establish a
1% sales tax to support aquatic plant management activities. Tax dollars will be used first to
insure that the public use areas are managed, but can be used elsewhere on the lake when
available. Funds not used in a specific year, will be placed in an aquatic plant management trust
fund and used when needed in subsequent years. The aquatic plant management trust fund will
be capped at $250,000."
Levels of control that need to be considered
are:
Principle 5 - Develop an action Plan and program to monitor
the success or failure of any management activities.
The type and extent of plant growth and timing of
treatment.
Finally the following is an example of a recommended treatment scenario produced for
Lake Tranquil:
In reviewing control options, it is important to understand both the extent and the life
cycle of the problem plant species. What is the area of problem growth? If the infested area is
small (say, 0.25 acre), then large-scale methods, like grass carp, would be inappropriate. The
same is true for large-scale problems treated with small-scale methods. What is the plant's typical
life cycle? Some plant species with early-season growth are more susceptible to treatment in the
springtime. In other situations, winter treatment may be most effective.
How long will the plant be controlled? Is duration of control short-term (a month, a
growing season) or longer term (1 year, 2 years, 5 years or more)? Do not fall into the trap that a
short-term control is only cosmetic and should not be done, if short-term control helps reach the
overall lake management objective(s), it is the right way to go.
Does the site have many submerged logs or bottom debris or water intake pipes that would
hamper bottom treatments like rotovation or bottom barrier application? Are there many surface
obstacles such as docks or buoyed areas that could interfere with surface operations of
mechanical cutting or harvesting? Are there non-barricadable streams that would allow grass
carp to escape?
If specialized equipment is to be purchased for the control project, determine the cost of
buying, operating and maintaining it. Include replacement costs and staff wages and fringe
benefits if volunteers can do the job. Above all else select an aquatic plant management
technique that the users can afford. Know what will sell!
Will the control option restrict use of the water body after treatment by banning water
contact or ingestion (swimming, fishing, drinking or irrigation use)? Does the operation of large
machinery or equipment occur at a peak time of recreational use? Does this control option
represent a severe safety hazard or interfere significantly with normal use?
Does the aquatic system have important spawning sites? If so, control activities that
disturb the bottom would be prohibited during certain critical periods. The presence of
endangered, rare, or sensitive plants or animals utilizing aquatic plant beds could also limit the
use of certain control methodologies.
What are the projected short-term and long-term environmental impacts? Is there a risk
that controls for the sake of maximizing human use, can seriously jeopardize an important
segment of the native aquatic plant or animal community? Consider the possibilities, but develop
a realistic assessment of the probable impacts.
If aquatic plant management is going to have an environmental effect are there possible
mitigation techniques that can reduce or eliminate impacts. Some aquatic plant control
techniques pose higher risks of removing non-target organisms, particularly emergent vegetation
along the shoreline. Estimates should be made of the types and areas of plant species that may be
affected by the control techniques. Lost areas can be mitigated by replanting with nursery stock
plants or plants harvested from local areas (check on local harvesting restrictions). Volunteers
can often help with revegetation efforts, if needed.
Find out what is legal! Are permits are necessary? Is a fee required? What is the expected
time it takes to process the permit application(s)? The length of time involved in processing
different permit applications can vary enormously.
"I. Whole-lake diver surveillance for milfoil locations (spring).
I - Problem statement
II - Management goals
III - A list of waterbody and watershed characteristics from previous studies or current sampling
work
IV - A map showing beneficial and recreational use areas of the water body
V - A map showing types and locations of aquatic plants
VI - A written characterization of aquatic plants
VII - A discussion of aquatic plant controls, examining pros and cons of use in the water body
(results can be presented in a matrix format)
VIII - A control intensity map showing proposed control areas in water body
IX - Description of public involvement program, including specific examples.
X - A list of action strategies, both short- and long-term, and time frames
XI - A description of the monitoring and evaluation process to be used.