upper long lake improvement...
TRANSCRIPT
Upper Long Lake Improvement Study
By: Restorative Lake Sciences
November, 2014
Upper Long Lake Depth
Contours
Upper Long Lake Bottom
Hardness
Upper Long Lake Soils
Upper Long Lake Immediate
Watershed
• 900 acres
• Watershed is 7.4X lake
size = small to
moderate watershed =
moderate pollution
Upper Long Lake Invasive
Bi-valves
Upper Long Lake Water
Quality Sampling Locations
Upper Long Lake Water
Quality Data (July, 2014)
Upper Long Lake Sediment
Data (July, 2014)
Upper Long Lake Invasive
Species
Upper Long Lake Invasive
Species
Hybrid Watermilfoil
(Eurasian Watermilfoil + Native
Watermilfoil)
Grows thicker, wider, faster than EWM
and is VERY TOLERANT to herbicides!
EWM Overgrowth in Other Lakes:
Upper Long Lake Milfoil
Distribution
Upper Long Lake Starry
Stonewort Distribution
Upper Long Lake Invasive
Curly-leaf Distribution
Upper Long Lake Emergent
Invasive Distribution
Upper Long Lake Aquatic
Vegetation Biovolume
Upper Long Lake Native
Aquatic Plants
What Happens if We Kill Too Much
Vegetation ?
Toxic Blue-green algae
bloom, Spring Lake,
Ottawa County, MI
Lake may not be able to
break down plant matter
fast enough
What Will Happen If We Do
Nothing?
• EWM will displace native
aquatic plant species
• Fishery will decline in
quantity and quality
• Excessive die-off of
massive EWM beds will
cause major declines in
water quality parameters
• Hydrilla or other species
may invade and further
destroy the lake
Laminar Flow Aeration Components
End-on view:
non-turbulent
flow
Ceramic diffuser
head and anchor
CASE STUDIES OF AERATION ON
MILFOIL REDUCTION AND SEDIMENT
NUTRIENT REDUCTION IN OTHER
MICHIGAN LAKES
EWM Reduction of 80 acres with
LFA
Pickerel Lake, 2013 Pickerel Lake, 2014
Design courtesy of
Clean-Flo, Inc. &
Lake Savers
Changes in South Basin WQ before
and after Inversion Oxygenation
Date Water Column
DO
(mg/l)
Sediment
DO
(mg L-1)
Redox
Potential
(mV)
Nov 11, 2010
Nov 13, 2013
10.9± 1.2
11.9± 0.6
0.33±0.6
6.5±0.9**
-69.8±27
30.2±9.6**
** Statistically significant
Changes in South Basin Sediments before
and after Inversion Oxygenation
Date Sediment
NH3+
(mg/kg)
Sediment
Nitrate + Nitrite
(mg/kg)
Nov 11, 2010
Nov 13, 2013
331±97
192±52**
37.5±59
3.5±0.1**
Conclusions
• No significant differences in water column DO (due to shallow depths)
• Significant differences in water column redox potential (oxidative state post-aeration)
• Significant differences in sediment DO post-aeration (increase)
• Significant differences in both sediment ammonia and nitrate/nitrite (both decreased)
• This data set yields insight into inversion oxygenation mechanism
• Observed changes in sediments may also explain reduction in ammonia-loving aquatic vegetation (i.e. milfoil)
Mechanical Harvesting
Benefits of Harvesting
• Removes some plant
debris and associated
organic nutrient
• Can reduce need for
herbicides but is
generalist
• Should not be used on
species that fragment
Limitations of Harvesting
• Can increase biomass of
fragment-producers
• Does not exclude need
for treatments in “high-
maintenance” lakes
• Can create floating debris
• May need to be repeated
in single season due to
re-growth
Chemical Herbicides
• Applied to both exotic and native aquatic plants
• Most commonly used: 2,4-D, Reward, Triclopyr, Fluridone, Aquathol-K, CuSO4, Glyphosate
• Requires MDEQ permit; residue sampling may be required (i.e. Triclopyr, Fluridone)
• Shallow well restrictions, swimming restrictions, watering restrictions-Notifications required
Biological Control: Weevil
Benefits
• Non-chemical agent
• Self-propagating
• Fast turn over rate on life
cycle within a given
season
• No strong evidence of
fishery predation
Limitations
• Uncertainty exists on
stocking density needs
• Stocking density needs
may be highly site-
specific
• May not be able to keep
up with fast growth rate of
EWM growth
• Response to hybrid
strains of milfoil??
2015-2019
Recommendations
• Treat existing EWM with Triclopyr granular or liquid
with adjuvant (proposed to be mid May-mid June)
in 2015
• Harvest 3-4 weeks post-treatment to remove dead
EWM biomass
• Install LFA aeration system and use
enzymes/bacteria to reduce the muck that is
feeding the EWM (mostly ammonia and nitrate)
• Implement oversight and monitoring program (RLS)
along with community education project
• Restoration instead of stagnant management