A Case Study in Lake Management Issues
47
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
description
A Case Study in Lake Management Issues. Ed Dunne, Ph.D , Division of Environmental Sciences, SJRWMD P.O. Box 1429, Palatka, FL 32178; Email: [email protected] ; ph: 386-329-4227. Overview. Issues in lake management Approach to lake restoration/enhancement Lake Apopka and historical sketch - PowerPoint PPT Presentation
Transcript of A Case Study in Lake Management Issues
Ed Dunne, Ph.D, Division of Environmental Sciences, SJRWMDP.O. Box 1429, Palatka, FL 32178; Email: [email protected]; ph: 386-329-4227
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
Overview
Water Management Districts in Florida
18 Counties in the Districts
Ten 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
Lakes, 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
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
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 Apopka
A lake and it’s watershed
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
Sources: Lake Apopka External Nutrient Budget 1989-2002; Schelske et al., 2005.
Basin Land Use Changes
Major Former Farm Areas
Source: Lake Apopka External Nutrient Budget 1989-2010
Source: Lake Apopka External Nutrient Budget 1989-2010
Basin 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 1900-2002
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
0.0Tota
l pho
spho
rus
Load
ing
to L
ake
Apop
ka g
/m2
TMDL
Apopka SpringSHPMWGPCFJohns LakeBasin RunoffRainfallFarm Pumps
Phosphorus Loading to Lake Apopka 1989-2010
0
0.1
0.2
0.3
0.4
1987 1991 1995 1999 2003 2007 2011
Tota
l Pho
spho
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)
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
Lake
Sta
ge f
t N
GVD
192
9
Tota
l Pho
spho
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
Lake
Sta
ge f
t N
GVD
Tota
l Pho
spho
rus
met
ric to
ns
Year
Lake Apopka Total P Mass (Annual)Lake Stage (Annual)
P Mass at Target P Conc
and Mean Stage
Total P (metric tons) and Stage
R² = 0.9106
0
40
80
120
0 100 200 300
Chlo
roph
yll
a ug
/L
Total Phosphorus ug/L
Lake Apopka, annual mean values1989 - 2010
Relationship between chl. a and total P
0
50
100
150
200
1987 1991 1995 1999 2003 2007 2011
Chl
orop
hyll
ug/L
Year
Lake Apopka Chlorophyll (Annual, Monthly)
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
Lake
Sta
ge ft
NG
VD 1
929
Chl
orop
hyll
aug
/L
Year
Lake Apopka Chlorophyll (Annual)Lake Stage (Annual)
Chlorophyll a (µg/L)
Relationship between TSS and chl. a
R² = 0.7064
0
40
80
120
0 50 100 150
TSS
mg/
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
TSS
mg/
L
Year
Lake Apopka TSS (Annual, Monthly)
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
Lake
Sta
ge f
t N
GVD
Tota
l sus
pend
ed s
olid
s m
etric
tons
Year
Lake Apopka TSS (Annual)Lake Stage (Annual)
Total Suspended Solids (mg/L)
0
0.1
0.2
0.3
0.4
0.5
1987 1991 1995 1999 2003 2007 2011
Tran
spar
ency
m
Year
Lake Apopka Secchi Transparency (Annual, Monthly)
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
Lake
Sta
ge ft
NG
VD 1
929
Tran
spar
ency
m
Year
Lake Apopka Secchi Depth (Annual)Lake Stage (Annual)
Secchi depth (meters)
Some management practices to help improve the lake
Within lakeWithin watershed
Reflooding Ag. lands back to Wetlands
RESULTS 2000 Initial flooding of Duda Sub-East 680 acres 2011 Flooding to date about 10,000 acres
Phased ApproachEnvironmental Site Assessments, Risk AssessmentBA, BO, biota monitoring during floodingPrior 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 Flooding
Maps produced by P. Bowen
2005
Phased Approach to Flooding
Maps produced by P. Bowen
2010
Phased Approach to Flooding
Maps produced by P. Bowen
2011
Phased Approach to Flooding
9,870 acres flooded
Maps produced by P. Bowen
Gizzard Shad Harvest on Lake Apopka 1993 - 2010
RESULTS 450-500 mT/yr of fish
harvested P removal in fish = 2-3
mT/yr
GOALSRemove P in fish bodies Reduce recycling of P caused
by bottom feedingReduce turbidity caused by
bottom disturbance
Gizzard Shad Harvest on Lake Apopka 1993 - 2010
Marsh 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
GOALSMaximize 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
Tota
l P re
mov
ed m
etri
c to
nsMarsh Flow-Way Total Phosphorus Removal
November 2003 through December 2010
Efficiency = 28%
Cum
ulat
ive
tota
l P re
mov
ed m
etric
ton
s
Total 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
Cum
ulat
ive
solid
s re
mov
ed m
etrc
tons
Solid
s re
mov
ed m
etri
c to
ns
Marsh Flow-Way Total Suspended Solids Removal
November 2003 through December 2010
Efficiency = 91%
Total Suspended Solids
0
100
200
300
400
500
600
700
0
25
50
75
100
125
150
2001 2003 2005 2007 2009 2011
Cum
ulat
ive
TN r
emov
ed m
etric
ton
s
TN r
emov
ed m
etri
c to
ns
Marsh Flow-Way Total Nitrogen Removal
November 2003 through December 2010
Efficiency = 22%
Total Nitrogen
Evidence for Lake Improvement
0.000
0.100
0.200
0.300
1987 1991 1995 1999 2003 2007 2011
Tota
l Pho
spho
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)
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 2.92000 6.22003 02006 13.62008 02009 13.52011 50
Changes in areal coverage of Vallisneria americana along Lake Apopka shoreline
