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9/29/2020
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USACE operations update: Lake Okeechobee
Ian Markovich & Jessica Fair
Lake Okeechobee• Largest freshwater lake in Florida. 8th largest Freshwater lake in the nation.
• Covers 730 square miles
• 1905‐ First documentation of Water Hyacinth causing Nav. issues
• Health of the lake heavily depends on water levels
• Water level managed by LORS 2008, replaced by LOSOM (2022)
• Current Lake Level: 15.10’
• Ranked 18th best bass lake in the Southeast by Bassmaster in 2019
INVASIVE SPECIES MANAGEMENT BRANCH MISSION1. NAVIGATION2. FLOOD CONTROL3. ENVIRONMENTAL RESTORATION
Management History
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FY90 FY91 FY92 FY93 FY94 FY95 FY96 FY97 FY98 FY99 FY00 FY01 FY02 FY03 FY04 FY05 FY06 FY07 FY08 FY09 FY10 FY11 FY12 FY13 FY14 FY15 FY16 FY17
Lake
level (ft)
Treated
floating plants (acres)
Run 25 ‘92‐’00
Lake Okeechobee Treated Acreage
LORS ‘08‐CURRENT LOSOM (2022)
WSE ‘00‐’08
WSE‐Water supply and EnvironmentLORS‐ Lake Okeechobee Regulation ScheduleLOSOM‐ Lake Okeechobee System Operating Manual
• 1920’s‐1982 USACE Operated Inhouse Spray Crews• Maintenance Control‐ Lowest Feasible Level • Integrated Pest Management
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What Happened in ‘86?
Hurricane Bob
July 1985
Algae bloom
August 1986
30 day spray pause
Executive order
Harvesting
August 23rd
Algae bloom Spray Moratorium
Plants took over
Spray Implemented
November
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August September October November
Plant Acreages
Months
Increase in Hyacinth and Lettuce during Moratorium ‘86
Navigation Blockages:‐Moore Haven canal‐Sportsman's run ‐Kissimmee river ‐Taylor creek
Coordination Between Agencies
Lake Okeechobee Aquatic Plant Management Interagency Task Force• Established in 1986
• Engages agencies involved with Lake Okeechobee:USACE (Chair)
Florida Fish and Wildlife Commission (FWC)
South Florida Water Management (SFWMD)
Audubon
University of Florida (UF)
Lee County Hyacinth Control district
• bi‐monthly meetings
• monthly Lake Okeechobee flyers
• The focus of the meetings is to use multidisciplinary technical strategies and scientific data to develop management and research plans that benefit the overall ecological health of the lake.
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Interagency Flights• Monthly aerial surveys
• One member from each respective agency
Interagency Flyers
Hurricane Irma
September 2017
Increased water levels
Increased Turbidity Decreased SAV,
Emergent Vegetation
Algae bloomSpray Pause
4 Months
Increased Invasive acreage
Decreased water levels
Decreased Turbidity
Increase SAV, Emergent vegetation,
History Repeats Itself- Public Perception
Where are we now?
• Public members are happy about lake clarity• Mad about plant acreage being so high.
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**2,700
2,579
4,670
2,562
Effects of Spray Pause• Occurred in January‐May 2019 • No longer in Maintenance control • Blockages• Potential for more herbicide use• Potential aerial
Harvesting Demo
Total cost $37,671
• 1 barge= ~15yd3
Tuesday‐ 3 barges = 45yd3
1 barge broke down~ 3hrs
Wednesday‐ 11 barges = 165yd3
Only 1 barge active until 12pm
Thursday‐ 10 barges = 150 yd3
Both barges active
• TOTAL effective hours= 16
• TOTAL material collected = 360 yd3 = 22% of 1 acre
• Machines‐‐2 Shallow water harvesters, 2 Pontoons, 1 Excavators
• Employees‐‐5 Operators
• Disposal site‐~4 miles from harvesting site
• Cooperative agreement (cost share) with FWC deemed unusable by OC
• Navigation and Flood control structures on both routes 1&2.
• To maintain Corps missionsUSACE will be conducting spraying on Lake Okeechobee via contractors
Treatment areasRim canal from Port Mayaca to Old Sportsman's. Pelican Bay to Uncle Joe’s cut.
Recent Events
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Treatment Plans
• Will go out to public and agency members• Interagency group
• What's Happening on my Lake
• Main targets: water hyacinth (Pontederia(Eichhornia) crassipes) and water lettuce (Pistiastratiotes)• Other targets: Cuban bulrush (Oxycaryum cubense), Tropical American watergrass (Luziola subintegra), Feathered mosquitofern (Azolla pinnata)
Invasive Plant Surveys• Surveying ~100 hours per month.
• Use GAIA App to track and determine acreage of floating plants
• Each polygon surveyed monthly.
• Monthly ground data is compared with monthly flight data
Survey Reports
• Developed a rating based system to prioritize areas of the lake that need treatment.
• Based on characteristics/impacts• Work closely with FWC to determine which areas are
most impacted
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Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Zone 7 Zone 8 Zone 9 Zone 10
Acreage
Months
Monthly Total Plant Acreage Per Zone
APRIL MAY JUNE JULY AUGUST
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Acreage
Month
Ground vs Flight Surveys
GROUND FLIGHT
Compiling Survey Data • Survey polygons combine to match flight zones
• August**
• Benefits• Help get a better understanding of plant populations around lake • Aid management strategies
UAV Work
• Anafi
• USACE UAV team
• Mapping areas around the lake• East wall• Tropical American Water Grass(Luziola) in Fisheating bay
• Moratorium bird island• Coordinating with FWC
Questions?
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HHD Terrestrial Work
• USACE has been completing terrestrial invasive species work around the HHD
• Target species• Java Plum, Brazilian Pepper, Climbing Cassia,
Rosewood, Bamboo, Melaluca etc.
