ed dunne, ph.d, division of environmental sciences, sjrwmd p.o. box 1429, palatka, fl 32178; email:...
TRANSCRIPT
Ed Dunne, Ph.D, Division of Environmental Sciences, SJRWMD
P.O. Box 1429, Palatka, FL 32178; Email: [email protected]; ph: 386-329-4227
A Case Study in Lake Management
Issues
A Case Study in Lake Management
Issues
Issues in lake management Approach to lake restoration/enhancement Lake Apopka and historical sketch Time series of:
basin changes and nutrient loading Nutrient budgets and water quality trends
Total P, Chl a, Transparency, TSS Management practices
Within watershed, within lake Lake Improvements
Accessing lake data Water levels and water quality
OverviewOverview
Water Management Districts in Florida
Water Management Districts in Florida
18 Counties in the Districts18 Counties in the Districts
Ten Major WatershedsTen Major Watersheds
Good waters
10%
90%
Lakes, Reservoirs, and Ponds
Good WatersImpaired Waters
Source:http://iaspub.epa.gov/waters10/attains_state.control?p_state=FL#total_assessed_waters
Florida 2010Lakes, Reservoirs, and Ponds 2010
Florida 2010Lakes, Reservoirs, and Ponds 2010
Lakes, Reservoirs, and Ponds 2010:Causes of impairmentLakes, Reservoirs, and Ponds 2010:Causes of impairment
Mercury26%
Nutrients27%Iron
10%
DO11%
Alkalinity2%
Turbidity12%
pH6%
Ammonia5%
Source: http://iaspub.epa.gov/waters10/attains_state.control?p_state=FL#total_assessed_waters
Multipronged approach to deal with impairment
Restoration/Enhancement
Multipronged approach to deal with impairment
Restoration/Enhancement
Reduce nutrient load to the lake
Cost effective nutrient program to: Remove Reduce
Source ControlWithin Watershed
Mitigate LossWithin Lake
Controlling and Mitigating Eutrophication
Reduce P loading
Lower P concentration & plankton
Increase water transparency
Increase SAV
Increase game fish Time
Improved Ecosystem Health
Multipronged approach to lake improvement Multipronged approach to lake improvement
Lake water quality
Water levels Restoring Wetlands
Storm water
Acquiring land
TMDLControl of Hydrilla
Planting littoral zone
Marsh Flow-Way
Shad Harvest
Within Watershed
Within Lake
Lake ApopkaLake Apopka
A lake and it’s watershed
A lake and it’s watershed
Lake ApopkaHistorical timeline: 1880s-
2010s
Lake ApopkaHistorical timeline: 1880s-
2010s 1880s Land around the lake $0.25/acre 1890s Apopka Beauclair Canal 1920s Sewage, wastewater, hurricanes (6-8ft) 1940s Muck farms on NS, lake levee, hurricanes, blooms, <
SAV 1950s Water control structures on ABC 1960s Fish kills, pesticide use by agriculture 1970s State/federal restoration, bacterial disease, bass failing,
4 fish camps 1980s Tower Chemical, fish kill, Apopka and SWIM Acts, no fish
camps, pilot projects initiated, $15 million land purchase
1990s FOLA, MFW pilot project, shad harvest, Act ’96 (P criterion), $100 million land purchase, bird die
off 2000s TMDL, MOU, MFW, reflooded 5,000 acres of NSRA 2010s Bird list = 346 sp., MFW, shad, BMAP projects, reflooded
10,000 acres, > SAV
Time series:Basin changes, P
loading, and water quality
Time series:Basin changes, P
loading, and water quality
Sources: Lake Apopka External Nutrient Budget 1989-2002; Schelske et al., 2005.
Basin Land Use ChangesBasin Land
Use Changes
Major Former Farm Areas
Major Former Farm Areas
Source: Lake Apopka External Nutrient Budget 1989-2010
Source: Lake Apopka External Nutrient Budget 1989-2010
Basin Land Use ChangesBasin Land
Use Changes
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Phosphorus Loading to Lake Apopka 1900-2002Phosphorus Loading to Lake Apopka 1900-2002
Measured
Estimated from literature
Load
ing
g m
-2 y
r-1
Year 20092007200520032001199919971995199319911989
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Tota
l phosp
horu
s Lo
adin
g t
o L
ake
Apopka
g/m
2
TMDL
Apopka SpringSHPMWGPCFJohns LakeBasin RunoffRainfallFarm Pumps
Phosphorus Loading to Lake Apopka 1989-2010Phosphorus Loading to Lake Apopka 1989-2010
0
0.1
0.2
0.3
0.4
1987 1991 1995 1999 2003 2007 2011
To
tal P
ho
sp
ho
rus
mg
/L
Year
Lake Apopka Total P (Annual, Monthly)
Target P 0.055 mg/L
Total Phosphorus (P) (mg/L)
Total Phosphorus (P) (mg/L)
Total Phosphorus (P) (mg/L)
Total Phosphorus (P) (mg/L)
63.50
64.50
65.50
66.50
67.50
0.00
0.05
0.10
0.15
0.20
0.25
0.30
1987 1991 1995 1999 2003 2007 2011
La
ke
Sta
ge
ft
NG
VD
19
29
To
tal P
ho
sp
ho
rus
mg
/L
Year
Lake ApopkaTotal P (Annual)
Lake Stage (Annual)
Target P 0.055 mg/L
63.50
64.50
65.50
66.50
67.50
0
20
40
60
1987 1990 1993 1996 1999 2002 2005 2008 2011
La
ke
Sta
ge
ft
NG
VD
To
tal
Ph
os
ph
oru
s m
etr
ic t
on
s
Year
Lake ApopkaTotal P Mass (Annual)
Lake Stage (Annual)
P Mass at Target P Conc
and Mean Stage
Total P (metric tons) and Stage
Total P (metric tons) and Stage
R² = 0.9106
0
40
80
120
0 100 200 300
Ch
loro
ph
yll
a u
g/L
Total Phosphorus ug/L
Lake Apopka, annual mean values1989 - 2010
Relationship between chl. a and total P
Relationship between chl. a and total P
0
50
100
150
200
1987 1991 1995 1999 2003 2007 2011
Ch
loro
ph
yll
ug
/L
Year
Lake Apopka Chlorophyll (Annual, Monthly)
Chlorophyll a (µg/L)Chlorophyll a (µg/L)
63.50
64.50
65.50
66.50
67.50
0
40
80
120
1987 1991 1995 1999 2003 2007 2011
La
ke
Sta
ge
ft
NG
VD
19
29
Ch
loro
ph
yll
au
g/L
Year
Lake Apopka Chlorophyll (Annual)
Lake Stage (Annual)
Chlorophyll a (µg/L)Chlorophyll a (µg/L)
Relationship between TSS and chl. aRelationship between TSS and chl. a
R² = 0.7064
0
40
80
120
0 50 100 150
TS
S m
g/L
Chlorophyll a ug/L
Lake Apopka, annual mean values1989 - 2010
0
40
80
120
160
200
1987 1990 1993 1996 1999 2002 2005 2008 2011
TS
S m
g/L
Year
Lake Apopka TSS (Annual, Monthly)
Total Suspended Solids (mg/L)
Total Suspended Solids (mg/L)
63.50
64.50
65.50
66.50
67.50
0
4000
8000
12000
16000
20000
24000
1987 1990 1993 1996 1999 2002 2005 2008 2011
La
ke
Sta
ge
ft
NG
VD
To
tal s
us
pe
nd
ed
so
lids
me
tric
to
ns
Year
Lake ApopkaTSS (Annual)
Lake Stage (Annual)
Total Suspended Solids (mg/L)
Total Suspended Solids (mg/L)
0
0.1
0.2
0.3
0.4
0.5
1987 1991 1995 1999 2003 2007 2011
Tra
ns
pa
ren
cy
m
Year
Lake Apopka Secchi Transparency (Annual, Monthly)
Secchi depth (meters)Secchi depth (meters)
63.50
64.50
65.50
66.50
67.50
0
0.1
0.2
0.3
0.4
0.5
1987 1991 1995 1999 2003 2007 2011
La
ke
Sta
ge
ft
NG
VD
19
29
Tra
ns
pa
ren
cy
m
Year
Lake ApopkaSecchi Depth (Annual)
Lake Stage (Annual)
Secchi depth (meters)Secchi depth (meters)
Some management practices to help improve the lake
Within lakeWithin watershed
Some management practices to help improve the lake
Within lakeWithin watershed
Reflooding Ag. lands back to WetlandsReflooding Ag. lands back to Wetlands
RESULTS
2000 Initial flooding of Duda Sub-East 680 acres
2011 Flooding to date about 10,000 acres
Phased Approach
Environmental Site Assessments, Risk Assessment
BA, BO, biota monitoring during flooding
Prior to flooding:
Field prep., which included soil amendment (3,000 ha; $2.5 m)
Remediation to reduce OCP - deep ploughing (1,620 ha; $9.6 m)
2000
Phased Approach to FloodingPhased Approach to Flooding
Maps produced by P. Bowen
2005
Phased Approach to FloodingPhased Approach to Flooding
Maps produced by P. Bowen
2010
Phased Approach to FloodingPhased Approach to Flooding
Maps produced by P. Bowen
2011
Phased Approach to FloodingPhased Approach to Flooding
9,870 acres flooded
Maps produced by P. Bowen
Gizzard Shad Harvest on Lake Apopka 1993 - 2010Gizzard Shad Harvest on Lake Apopka 1993 - 2010
RESULTS
450-500 mT/yr of fish harvested
P removal in fish = 2-3 mT/yr
GOALS
Remove P in fish bodies
Reduce recycling of P caused by bottom feeding
Reduce turbidity caused by bottom disturbance
Gizzard Shad Harvest on Lake Apopka 1993 - 2010Gizzard Shad Harvest on Lake Apopka 1993 - 2010
Marsh Flow-way 2003 - 2010Marsh Flow-way 2003 - 2010
REMOVAL RESULTS
TP: 2 mT, 28%, 0.8 g m-2 yr-1
TSS: 4,000 mT, 91%, 1,300 g m-2 yr-1
TN: 80 mT, 22%, 26 g m-2 yr-1
GOALS
Maximize P removal from the lake
Provide wetland habitat
-1
4
9
14
19
-1
0
1
2
3
4
5
6
7
2001 2003 2005 2007 2009 2011
To
tal P
rem
ove
d m
etri
c to
ns
Marsh Flow-Way Total Phosphorus Removal
November 2003 through December 2010
Efficiency = 28%
Cu
mu
lati
ve t
ota
l P
rem
ove
d m
etri
c to
ns
Total PhosphorusTotal Phosphorus
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
2001 2003 2005 2007 2009 2011
Cu
mu
lati
ve
so
lids
re
mo
ve
d m
etr
c t
on
s
So
lid
s re
mo
ved
met
ric
ton
s
Marsh Flow-Way Total Suspended Solids Removal
November 2003 through December 2010
Efficiency = 91%
Total Suspended SolidsTotal Suspended Solids
0
100
200
300
400
500
600
700
0
25
50
75
100
125
150
2001 2003 2005 2007 2009 2011
Cu
mu
lati
ve T
N r
emo
ved
met
ric
ton
s
TN
rem
ove
d m
etri
c to
ns
Marsh Flow-Way Total Nitrogen Removal
November 2003 through December 2010
Efficiency = 22%
Total NitrogenTotal Nitrogen
Evidence for Lake Improvement
Evidence for Lake Improvement
0.000
0.100
0.200
0.300
1987 1991 1995 1999 2003 2007 2011
To
tal P
ho
sp
ho
rus
mg
/L
Year
Lake Apopka Total P (Annual)
Target P 0.055 mg/L
Pre Post
Pre = period used to measure baseline loading for TMDL development (Magley, 2003)Post = period to include years with both normal and low lake stages
Total Phosphorus (P) (mg/L)
Total Phosphorus (P) (mg/L)
Changes in Lake ApopkaConcentrations & Loads
Changes in Lake ApopkaConcentrations & Loads
Parameter Units Comparison periodPre (‘89-’94) Post (‘03-’10)
Change
TP loading mT/yr 64 26 -59%
TP mg/L 0.21 0.11 -45%
Chl a µg/L 99 63 -37%
Secchi m 0.21 0.33 56%
TSS mg/L 86 67 -22%
TP mT 43 19 -55%
TSS mT 17,533 10,927 -38%
TN mT 1,112 715 -36%
Year Area (acres)
1997 2.9
2000 6.2
2003 0
2006 13.6
2008 0
2009 13.5
2011 50
Changes in areal coverage of Vallisneria americana along Lake Apopka shorelineChanges in areal coverage of Vallisneria americana along Lake Apopka shoreline
