Media Presentation Template

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Relationship of Flow to the Aquatic Faunas of
Florida Rivers, Springs, and Estuaries
Dr. Stephen J. Walsh U.S. Geological
Survey Gainesville, FL
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Apalachicola River
Largest River Discharge and Forested Floodplain
in Florida

• 110 (176 km) mi long
• 1-5 mi (1.6-8.1 km) wide
• 2,600 mi2 (6,734 km2) ACF basin area
• 175 mi2 floodplain area
• 86 years of flow data

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112,000 total FP acres
86,000 non-tidal
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Purple Bankclimber
Chipola Slabshell
Fat Threeridge
Gulf Sturgeon
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Floodplain Impairment

• Declining flows
• Increased droughts
• Increased sedimentation
• Diminished aquatic habitats
• Diminished water quality
• Fisheries declines
• Cumulative impacts

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http//pubs.usgs.gov/sir/2006/5173/
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River and floodplain changes since 1950s
More sand in forests
Less water in forests
Wider river channel
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1941 aerial photo 1999 in yellow

• Increase in width
• 50 Corley Reach
• 20 average for river

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Navigational Dredging

• 9 x 100 ft channel

• in-bank spoil disposal

Navigation Windows
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Connected Floodplain Habitat Relative to Flow
90,000
80,000
78,000 ac
70,000
60,000
50,000
Area of habitat, in acres
40,000
30,000
Annual flood 86,200 cfs
20,000
8,200 ac
10,000
0
5
7
10
30
20
50
70
40
100
200
Median flow 16,400 cfs
Flow (x 1000) cfs
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Extended low-water impacts on aquatic floodplain
communities

• Eliminates and disconnects habitats
• Fragments populations
• Reduces survivorship
• Alters nutrients food webs
• Concentrates predators
• Increased competition
• Diminishes water quality

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Light Traps
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How hydrologic alterations affect fish species.
Sources of stressors are in red, stressors in
yellow, mechanisms in blue, affected life-history
functions in green (modified from Wenger and
Freeman 2005).
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Apalachicola National Estuarine Research Reserve
Seafood 14-16 M dockside landings per
year Commercial value 70-80 M per year
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Livingston, R.J. 2008. Importance of River Flow
to the Apalachicola River-Bay System
http//mayorvanjohnson.com/blog/wp-content/uploads
/2008/10/livingston_report.pdf
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Florida Karst Landforms
(Spechler and Schiffer 1995)
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Elevated Nitrates (NO3)
Historical Baseline 0.05-0.1 mg/L
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Gemini Spring, Volusia County
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Wekiwa Spring discharge
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Florida law requires establishment of minimum
flows and levels of water bodies to prevent
significant harm associated with water
withdrawals.
Water Resources Chapter 373.042
(1)  Within each section, or the water management
district as a whole, the department or the
governing board shall establish the following
(a)  Minimum flow for all surface watercourses
in the area. The minimum flow for a given
watercourse shall be the limit at which further
withdrawals would be significantly harmful to the
water resources or ecology of the area.
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Minimum Flows and Levels (MFLs)
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Bioindicators

• Algae periphyton, filamentous, cyanobacteria
• Macrophytes
• Benthic macroinvertebrates
• Fishes
• Turtles
• Subterranean fauna
• Others birds, alligators

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Fore, L.S., R. Frydenborg, D. Miller, T. Frick,
D. Whiting, J. Espy, and L. Wolfe, L. 2007.
Development and testing of biomonitoring tools
for macroinvertebrates in Florida streams (stream
condition index and biorecon). FDEP Final Report.
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Stream Condition Index vs. Human Disturbance
Gradient
100
Median
25-75
Non-Outlier Range
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Outliers
r 0.72
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SCI
40
20
0
0.8
2.4
4.0
5.6
7.2
Human disturbance gradient