Loch Garry, Middle Lake and Lake Alexandria Restoration Program by 0JvAHr

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									Saving our lakes by using wind,
 solar and/or electric powered
        water circulators
             Lake eutrophication
• Natural and Cultural
  eutrophication
• Increase in nutrients =
  increase plant and animal
  life
• Once a lake becomes
  eutrophic, problems starts
  to occur, including fish
  kill, odors, abundant
  aquatic plants… algae
  bloom!
Aquatic plants in the littoral zone at
 different trophic stages of a lake
  Typical results of a lake infested
             with milfoil
• Oxygen profile of
  Loch Garry
                        Station 1 - July 31st 2005
                                                                                           Station 1 - Feb 23rd 2006
                      0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
                                                                                     0                 2              4               6
                 0
                                                                                0
                0,5
                                                                               0,5
                 1
    Depth (m)




                                                                   Depth (m)
                1,5                                                             1

                 2                                                             1,5
                2,5                                                             2
                 3                                                             2,5
                3,5
                                                                                3
                      Temperature (oC)   Dissolved oxygen (mg/L)
                                                                                         Temperature (oC)   Dissolved oxygen (mg/L)
      TSI index – Loch Garry status
                                                              Parameter                    Results

        Parameters                Carlson TSI                 Transparency (Secchi)        0,8m
Total Phosphorus                        63
                                                              Chlorophyll-a                17,0 g/L
Chlorophyll-a                           58
Secchi transparency                     63                    Total phosphorus             0,059 mg/L or 59 g/L

                      MEAN : 61




                                                         Eutrophic
                                                                                  Hyper-eutrophic
           Oligotrophic poor in                          Rich in nutrients,
                                  Mesotrophic                                     Pea-soup condition; Poor
           nutrients        and                          biologically      very
                                  Transition    status                            water transparency less
           biologically    non-                          productive. Oxygen
                                  between oligo and                               than 1m. Very low in
           productive. Rich in                           depletion        often
                                  eutrophic.    Slight                            oxygen.
           oxygen.                                       observed at bottom.
                                  oxygen depletion.
                  Eurasian milfoil
•Myriophyllum spicatum is a
perennial, submersed, vascular
plant.
•The plant can grow up to 6.5 m
in height and once it reaches the
surface it grows laterally to form a
dense canopy.
•The inflorescence (flower spike),
usually a few inches tall, is the
only part of the plant that grows
out of the water.
•Once established, it tends to
form a dense wall of vegetation.
            Milfoil reproduction
• In the fall, the plants are reduced to root crowns, and
  survive winter on non-structural carbohydrate (starches
  and sugars) storage. The crowns sprout in the spring
  and develop into adult plants that flower in mid to late
  July.
• It is not uncommon to see this plant overwinter in its
  evergreen state, as it tends to be quiescent with little
  metabolic activity in northern climates.
• Although it produces viable seeds, its primary means of
  reproduction is through vegetative propagation; stolons
  and fragmentation, both natural and induced (accidental
  cuttings from animals, human activities, wave action, or
  other factors).
    Problems associated with Eurasian milfoil

•   Multiple species stands are important in maintaining adequate habitat for aquatic life.
    Fish use these types of stands as shelter and feeding grounds, as a diversity of
    insects and prey inhabit these areas. When M. spicatum invades these areas, the
    dynamic changes as M. spicatum invasions most often result in successful
    competition against native lake flora.
•   Once established, M. spicatum often becomes the dominant specie, rendering the
    surrounding aquatic habitat inadequate for other plant or animal species, as fish
    rarely use dense stands of vegetation with more than 250 stems/m2.
•   The usually dense stands of invasive plants provide healthy nesting grounds for
    noxious insects, such as mosquitoes that thrive in stagnant waters. Also, these
    monospecific stands provide poor habitat for waterfowl.
•   Along with ecological problems that are found as a result of exotic species invasion
    lie economical problems. Lakes, and their surrounding properties, suffering from the
    intrusion of such macrophytes see their value diminish
•   Canopies and dense stands of aquatic vegetation restrict swimming, water skiing,
    fishing and boating. Commercially, these macrophytes have an impact on commercial
    boating, power generation from hydro-electrical dams, water supplies (drainage
    and filtration systems), flood control and housing development since they inhibit
    water flow, obstruct waterways and impede upon activities.
Eurasian Milfoil control techniques
Herbicides
• Herbicides, such as 2,4 D or Fluridone, are only a short term solution.
   More and more studies show that they have major negative impacts
   such as die-offs of native vegetation, increases in green algae and/or
   cyanobacteria (blue-green algae), and effects on invertebrates and fish
   through loss of habitat.
• As the plants die off, new organic matter is generated, resulting in an
   increase in biological oxygen demand. This demand creates a severe
   oxygen depletion which may cause winter and summer fish kills, toxic
   gas production, odours and foul taste.
• Although the interaction of these chemicals within the food chain and
   effects on humans is not fully known, many scientists are reconsidering
   the use of these chemicals. Even though this technique is still used in
   the United States, more and more Lake Conservation Associations and
   lake users are mobilizing to ban the usage of herbicides and are moving
   towards ecological means of control.
• We strongly discourage the use of herbicides. Algae bloom (possibly
   cyanobacteria) could result from the high nutrient levels made readily
   available following the sudden death of milfoil. Human health, aquatic
   ecosystem balance and the lakes overall quality could be at risk.
Weed harvesters
• Weed harvesters are also a short term solution.
  Experience acquired on many lakes has shown
  that the actual density of milfoil doesn’t
  decrease with this technique. Harvestings
  usually have to be done 3 to 5 times during the
  summer to keep the surface free of emerging
  stems. These costly machines (lowest price
  encountered was $80 000 US) are very
  expensive to operate.
Biological control
• Biological control, which involves the introduction of one species to
   control another, has been used in a number of cases. Since 1991, a
   North-American aquatic weevil (Euhrychiopsis lecontei) has been
   studied as a potential biological control agent for M. spicatum. This
   weevil, which uses the milfoil as a primary food source directly affects
   milfoil and is thereby species specific.
• Since the feeding source (sediments) of the milfoil is not affected the
   lake’s trophic status might deteriorate with the addition of new layers of
   dead milfoil at the sediment level. Therefore, oxygen consumption could
   increase due to higher biological activity and beneficial living aquatic
   organisms could be lost. No data is available to compare lakes trophic
   status before and after the introduction of the weevils.
• We believe that milfoil cannot be fully eliminated in large lakes, thus
   reintroduction of milfoil in treated areas is most likely probable.
• The cost of this technique is unusually expensive.
Water draw down

This technique, usually performed during summer or just before winter, could be possible
    in reservoirs. By drying out the littoral zone of the lake or by bringing down the water
    level in order to eliminate the plants by freezing, milfoil (and most aquatic plants)
    could be controlled in shallow areas.

But because reservoirs are also the water source for the towns, we believe that this
    technique cannot be considered in many cases for the following reasons:
• Reduction of total water volume could result in water shortage
• While using this technique, oxygen levels might decrease to anoxic levels due to the
    decomposition of a large volume of organic matter (dead plants and aquatic
    organisms)
• Native aquatic plants, needed to colonize the lake, will also be reduced or eliminated
• Reduction and/or elimination of fish habitat will result in the loss of many fish species
• Reduction and/or elimination of invertebrates that are part of a balanced aquatic
    ecosystem
• In a eutrophic lake, the addition of nutrients through decomposition might create other
    problems such as major algae blooms and might deteriorate a lake to the point of
    making it reach rapidly the hyper-eutrophic status
              Solutions



Electric,
Wind and
Solar
powered
water
circulators
       Water aerators/circulators
• This technique has shown to be in accordance with every ecological
  principle that is known and that must be considered in any lake
  restoration program.
•  oxygen =  animal life =  diversity of aquatic organisms =
  balance in aquatic ecosystem = control of Eurasian milfoil
  overgrowth
• Most importantly, this technique is not just specific to milfoil control
  (as with many other techniques) it reverses the overall
  eutrophication process of a lake. Through this process, weeds,
  algae and organic matter become an available source of nutrients
  primarily for animals (as opposed to plants), including fish.
• The primary energy source in a lake no longer benefits mostly plant
  life, but is distributed more uniformly throughout a balanced aquatic
  food chain.
How does it work?
 Given that milfoil spreads via fragments, to what extent does the action of the
          impeller create fragments that can spread by laminar flow?


• If the water circulators are installed during the summer (when the
  milfoil stems have reached the near surface) a negligible amount of
  fragments could be produced. Motorboats and vegetative
  fragmentation will create more fragments than a water circulator.
  We have seen lakes where motorboats are prohibited that became
  completely infested with milfoil within a period of less than 3 years.
• Natural reproduction of milfoil by vegetative fragmentation is an
  unsolvable problem for lake managers that want to control milfoil
  propagation once the plant is established. Actually, the risk of milfoil
  propagation is greatly reduced with water circulators. We have
  observed in most cases a drastic drop in milfoil density and total
  length of stems around the water circulators.
• The return of oxygen recreates a favourable environment for
  competition at the sediment level for the same source of nutrients
  (through bacterial and invertebrate activity) and a reduction of
  available nutrients through oxidation.
• Oxygen/temperature
Taken from a lake that also has a maximum depth of 80 feet.




                                     March 8, 2000                                                             March 8, 2000
                     0    2      4          6   8      10      12         14                   0   2     4      6     8      10    12     14    16
                 0                                                                         0

                 1                                                                         1
     Depth (m)




                                                                               Depth (m)
                 2                                                                         2

                 3                                                                         3

                 4                                                                         4

                         Temperature (oC)       Dissolved oxygen (mg/L)                            Temperature (oC)       Dissolved oxygen (mg/L)




     In milfoil stand                                                                          In milfoil stand with
     without circulators                                                                       circulators

          During summer, high water temperatures measured at the surface of a milfoil stand will promote multiple
          periods of flowering and fragmentation.
          Example: On July 31st 2005, the surface temperature in this milfoil stand at Loch Garry went up to 31oC,
          thus promoting flowering and fragmentation. At this same site, 1.5m below the water surface, the water
          temperature was only 23 oC. An ascending water flow, created by wind or solar powered circulators, will
          prevent extreme water temperatures, therefore limiting the number of flowering periods in a given summer.
Does photosynthesis, induced by creating an ice-free (and snow) area
                 during winter, influence milfoil?

• Wisconsin DNR describes Eurasian Water Milfoil as being
  opportunistic since it is adapted for rapid growth early in spring.
  Stolons, lower stems, and roots persist over winter and store the
  carbohydrates that help milfoil claim the water column early in
  spring, photosynthesize, divide, and form a dense leaf canopy that
  shades out native aquatic plants. Its ability to spread rapidly by
  fragmentation and effectively block out sunlight needed for native
  plant growth often results in monotypic stands.
• We believe that, by creating open areas during winter,
  photosynthesis continues to occur. This, with a combination of
  control factors (temperature, oxygen, water movement, reduction of
  nutrient level) will oblige the plant to use up some of its stored
  carbohydrates. Come spring, milfoil growth would then occur at a
  slow pace, allowing competition between milfoil and native
  plants.
     What are the impacts on other
       aquatic plant species?
• The impacts are variable. From our observations, sites that offered a
  thin sediment layer (3-6 inch) came back to their original sandy
  bottom, colonized by species usually found in oligotrophic lakes
  (such as Eriocolon septangulare) or not colonized at all due to an
  insufficient amount of nutrients for plant survival.
• In areas with thicker sediment layers, we found a variety of
  Pondweeds, Vallisnerias and Canada Waterweed, but not in dense
  formations usually encountered in eutrophic lakes. The new plant
  community is always in low density and size (or length) when using
  this technique.
• We would think that openings in milfoil stands would create
  opportunities for other invasive species to take over, but since this
  technology is not specific to a particular plant specie but mostly on
  what they thrive upon (nutrients), it is the overall trophic status of the
  lake that is being reversed (what is referred to as induced
  oligotrophication of a lake).
       Lake Echo in a natural state                 Lake Echo trophic status with todays nutrient inputs from watershed




                          Mesotrophic                                                                    Hyper-
Oligotrophic                                               Eutrophic                                     eutrophic

                 Total phosphorus before (1998) and after using wind powered water circulators (1999 to 2003).


                                      2003         1999/2001            2000            1998
Before          /           After
  Lake of Pointe-Calumet, Quebec
  Before and After
  at Lake Schryer,
(Montpellier,Quebec)
Which model to use and how many
       water circulators?
• We have used in the
  past 1 water circulator
  per 1 to 7 hectare (2,5
  to 17acres).
• Depends on depth,
  application (algae or
  plant control), nutrient
  levels, average wind
  speed, etc…                Our new wind powered water
                             circulator, specially designed for
                             lakes exposed to high winds
Location of Solar powered water
           circulators

								
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