Control Alternatives for Dams and Water Impoundments

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Control Alternatives for Dams and Water
Impoundments
Robert F. McMahon Center for Biological
Macrofouling Research Department of Biology The
University of Texas at Arlington
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DAM STRUCTURES FOULED BY ZEBRA MUSSELS
Structures Problems Dam Gates Abrasion of
seals, increased weight, corrosion, prevention
of operation Dam Gate Interiors Increased
weight, corrosion Drains Blockage of flow Pier
Nose Poor flow distribution Wickets Prevention
of Operation
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Structures Problems
Conduits, Culverts Reduction of flow,
corrosion and Piping Valves Interference
with operation, cavitation, seat damage Water
Quality Wet Prevention of operation due to
Wells fouling by mussels Trash
Booms Submergence due to increased weight,
corrosion
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ZEBRA MUSSELS IN IMPOUNDMENTS
Structures Problems
Navigation Submergence due to increased Buoys
weight, corrosion Public Beaches Accumulating
shells may cut or abrade the skin of swimmers,
odors of decaying mussels Boating and Fouling
of engine cooling and hulls Vessels Shore
Structures Submergence due to increased weight,
corrosion, interference with operation
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Structures Problems
Aquatic Ecology, Impacts on species
diversity, Trophic Dynamics, fisheries, food
chain dynamics, Energy Flow unionid mussels,
water clarity, productivity, growth of
macrophytic vegetation and sedimentation
rates
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ZEBRA MUSSEL MITIGATION AND CONTROL IN DAMS AND
IMPOUNDMENTS
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CONTROL OF MUSSELS ON DAM STRUCTURES
Dam Gates Manual removal toxic, metallic and
foul-release coatings disposable substrata
thermal treatment cathodic protection periodic
operation desiccation robotics Dam Gate
Interiors Manual removal hydroblasting, toxic,
metallic and foul-release coatings disposable
substrata thermal treatment desiccation
freezing Drains Manual removal, toxic, metallic
and foul-release coatings robotics thermal
treatment desiccation freezing hydroblasting
Pier Nose Disposable substrata toxic,
metallic and foul-release coatings cathodic
protection air bubbler systems desiccation
freezing
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Wickets Toxic, metallic, or foul-release
coatings thermal treatment manual removal
disposable substrata under water hydroblasting
periodic operation Rubber Side Seals on Gates
Periodic operation manual removal air bubbler
systems thermal treatment emersion Roller
Gate Tracks Manual removal periodic operation
cathodic protection Chains and Cables Manual
removal periodic operation Slots Manual
removal inserts periodic operation toxic and
metallic coatings
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Trash Racks Manual cleaning toxic and metallic
coatings make readily removable and
exchangeable thermal treatment cathodic
protection disposable substrata robotics
Conduits, Culverts and Piping Manual cleaning
line pigs toxic and metallic coatings
hypoxia/anoxia desiccation heated air thermal
treatment Valves Periodic operation
manual cleaning construction with toxic metals
thermal treatment desiccation heated air
thermal treatment Water Quality Wet Wells
Manual cleaning toxic or metallic coatings
molluscicides thermal treatment desiccation
heated air hypoxia/anoxia
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Trash Booms Manual cleaning, toxic, metallic or
foul-release coatings alternate replacement
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CONTROL ON IMPOUNDMENT STRUCTURES
Navigation Buoys Manual cleaning toxic,
metallic or foul-release coatings alternate
replacement hydroblasting Public Beaches
Manual removal design of removal
equipment? Boating and Vessels Manual
cleaning toxic or metalliccoatings
hydroblasting robotic hull cleaners Shore
Structures Manual cleaning metallic or
foul-release coatings hydroblasting robotics
disposable substrata desiccation thermal
treatment freezing
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CONTROL IN IMPOUNDMENTS AND NATURAL WATER BODIES
Complete eradication of zebra/quagga mussels from
large water bodies has not been accomplished
reduction in population densities may be possible
Why is Eradication Difficult?

• Treatment has to be targeted to affect only
  mussel populations
• Volume of water to be treated is generally very
  large
• Environmental impacts of the treatment must be
  acceptable
• Costs may be prohibitive

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Reduction in Population Densities

• Could be achieved under some circumstances
• Minimizes abiotic and biotic impacts of mussel
  infestation
• Reduces dam structure and raw water using system
  mussel impingement rates
• Lessens impact on nontarget species
• More cost effective than direct control

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CONTROL IN IMPOUNDMENTS AND NATURAL WATER BODIES
Water Level Drawdown Periodic level reduction
to below usual thermocline to expose mussel
populations to summer high temperature,
desiccating or winter freezing conditions Predato
rs Fish diving ducks crayfish muskrats
molluscivorous fish stocking programs (requires
further development) Parasites Targeted against
zebra mussels to control population densities
native or introduced (in early research stage)
may require extensive permitting for use
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Disease Organisms Bacterial or viral disease
vectors specific to zebra mussels utilized to
control population densities (in early research
stage) Microbial Toxins Chemical agents
developed from bacteria or algae that are toxic
to mussels (early stages of development no
commercial products available) Time Given
enough time zebra mussls populations may decline
to levels that reduce their impacts on
lake/impoundment infrastructure and ecology
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Planned Water Level Draw Downs Exposing Mussels
to Desiccating or Freezing Conditions

• Planned water level draw downs in order to emerse
  mussels in air

• Summer emersion and desiccation (lt10 Days)
• Temperature and humidity dependent responses
• Recreational and water user considerations
• Winter freezing (lt 1 day)
• Tolerance time decreases with decreasing
  subfreezing temperature
• Recreational and water user considerations

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Fish Predators of Zebra Mussels
Family Genus and Species Common
Name Clupeidae Alosa sapidissima American
Shad? Cyrinidae Cyrinus carpio Common
Carp? Catostomidae Ictibius bubalus Smallmouth
Buffalo Ictobius niger Black Buffalo Minytrema
melanopus Spotted Sucker Moxostoma
carinatum River Redhorse Percichthyidae Roccus
saxatilus Striped Bass Ictaluridae Ictalurus
furcatus Blue Catfish Ictalus punctatus Channel
Catfish ? Centrachidae Lepomis gulosus Warmouth
Lepomis macrochirus Bluegill Lepomis
microlophus Red Ear Sunfish ? Sciaenidae Aplodinot
us grunniens Freshwater Drum ? Acipenseridae Acipe
nser fulvesens Lake Sturgeon Perchidae Gymnocephal
us cernuus Ruffe ?? Gobiidae Neogobius
melanostomus Round Goby?? ?Greatest potential
for controlling zebra mussels ?Nonindigenous
species in the Great Lakes
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Bird Predation for Control of Zebra Mussels

• Diving duck and coot predation on zebra mussels
  is reported to reduce population densities by
  as much as 90 in some European Lakes
• Diving ducks reduce Asian Clam densities by
  67-80 in North America
• Diving ducks feed on zebra mussels in western
  Lake Erie
• Degree to which Diving ducks regulate the density
  of Lake Erie mussel populations is unknown
• Ducks do not appear to be regulating mussel
  densities in North America

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Other Predators Potentially Capable of
Regulating Zebra Mussel Densities

• Crayfish
• In Europe, Orconectes limosus averaging 90 mm
  long ate 93-114 juvenile mussels/day
• In N. A., crayfish feed on Asian clams
• Degree that crayfish could regulate N.A. zebra
  mussel populations is unknown

• Muskrats
• Have reduced native bivalve populations in N.A.
• Effects on zebra mussels are unknown

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Parasites

• There are a number of bivalve parasites
• Ciliates and Acetosporan protozoans
• Bacteria
• Nematodes
• Trematodes
• Olicochaetes (Chaetogaster limnaei)
• Hirudinea (leeches)
• Unionicolid Mites
• Capacity of parasites to regulate zebra mussel
  densities is unknown
• No reports of major reductions in zebra mussel
  population densities due to parasites in N.A.
  or Europe

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Diseases

• Bivalve population densities have been reduced by
  infectious diseases
• Bacteria (Vibrio and Pseudomonas) cause mass
  mortalities in oysters
• Such bacteria are not reported in zebra mussels
• Acetosporan, Haplosporidium nelsoni (MSX) reduces
  oyster populations by up to 95
• Similar Acetosporan-like infections occur in
  zebra mussels but do not induce mass mortalities
• No known viral diseases inducing massive
  mortalities in zebra mussel populations
• If identified, a disease organism could produce
  targeted control of mussel density in impoundments

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Targeted Bacterial Toxins

• Many bacterial species produce toxins that are
  relatively specific in their lethal effects
• Can be effective in controlling invasive species
  populations at very low concentrations
• If discovered, could allow targeted treatment of
  natural waters without greatly affecting other
  biota
• Requires extensive research to screen for
  potentially effective bacterial toxins
• Bacterial toxins have been discovered which
  induce mortality in zebra/quagga mussels
• Soil-water bacterium, Pseudomonas floresens
  (Molloy 1998)
• Four bacterial isolates from stressed mussels
  (Ji-Dong et al. 1994)
• Successful control applications have not been
  demonstrated in natural environments
• May not prove to be practical or cost-effective

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Time

• Exotic species often exhibit a massive population
  explosion immediately after invading a new
  habitat
• As resources are used up, population densities
  often decline to much lower levels
• Period for density decline is variable
• 2-50 years depending on species
• Asian clams have experienced major density
  declines in N.A. 15-20 years after invasion
• High densities occur only in new areas of
  invasion
• The zebra mussel population in Lake Oologah, OK,
  was extirpated in the summer of 2008 after
  several years of continual decline (McMahon,
  personal observation)
• The quagga mussel population in the 1000 Islands
  region of the St Lawrence River appears to be in
  decline (McMahon, personal observation)

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Time (cont.)

• Zebra mussels have experienced similar major
  population declines throughout Europe
• High densities only in newly invaded habitats in
  the Netherlands, Sweden and Russia
• Now have little impact in most European habitats
  where they were once very dense

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ERADIATION FROM IMPOUNDMENTS AND NATURAL WATER
BODIES

• Complete eradication of established zebra/quagga
  mussel may be possible in small isolated water
  bodies
• Millbrook Quarry Lake experience in Virginia
• 12 surface acres, 93 ft deep
• Lake did not have a flowing outlet
• Entire lake treated with potash (potassium
  chloride)
• 174,000 gal of KCl solution target
  concentration of 100 mg/l
• Aeration used to mix lake water across depth
• Monitored KCl levels throughout lake potash
  applied until lethal levels were achieved
  throughout
• 98-115 mg KCl achieved throughout
• Used live mussel samples to check for 100
  mortality
• Post-treatment monitoring supported 100
  successful eradication

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Conclusions

• No present techniques for totally eradicating
  zebra mussels from natural or source water
  habitats
• KCl (Potash) application may be used successfully
  in small water bodies under the right conditions
• Reduction in population densities may be achieved
  by control of water level
• Effective control by natural mussel predators,
  disease organisms, and bacterial toxins will
  require further research and development
• More effective density regulation technologies
  may be developed for open waters in the future
• Time is on our side

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PREVENTION

• The most effective control methodology is
  PREVENTION
• Assess vectors and threats for introduction of
  zebra/quagga mussels to a water body
• Develop and execute plans to prevent
  introductions
• Monitoring programs
• Educate the public encourage public cooperation
• Post warning signs at boat launches
• Eliminate all unattended boat launching sites
• Inspect all boats launched, particularly those
  from states harboring zebra/quagga mussel
  infestations
• Provide boat cleaning/mussel removal facilities
  at or near launch sites
• Monitor/control bait sales preventing
  introduction of bait from mussel-infested waters
• Review control plans developed for other water
  bodies
• Develop an effective rapid response plan