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1/18/2015
1
What it will take to improve the ecology
and water quality of Lake Kegonsa
Richard Lathrop
Jan. 17, 2015
Photo: R. Lathrop, Sept. 1985
1 pound of phosphorus (P) can
produce 500 pounds of algae! (Source: Vallentyne, 1974)
Photo: Bryce Richter,UW-Madison
Lake Kegonsa, June 2012
Photo: Dane Co. LWR Dept.
Blue-green algal blooms have been a problem in the
Yahara lakes since the early 1900s
Blue-green algae, which typically “bloom” during the
summer and early fall in nutrient-rich waters, create
serious water quality problems:
• Blooms can pile up as noxious scums on downwind shorelines
• Blooms consume oxygen causing fish kills
• Blue-green algae are generally inedible and not part of a lake’s
food chain supporting desirable fish
• Blue-green algae can produce toxins of concern to humans &
wildlife • Seizures & respiratory problems can result from neuro-toxins
• Liver & kidney lesions can result from hepato-toxins
Lake Kegonsa, June 2012
Photo: Dane Co. LWR Dept.
The Capital Times, Sept. 6-7, 2003
First recorded death in U.S. due to blue-green algal toxins! Madison, Wisconsin – July 2002
[The local teenager] …
[ …
…]
Yahara lakes &
watershed
Map: Dane Co. LWR Dept.
Mendota
Kegonsa
1/18/2015
2
Lake Mendota
Lake Area = 39.6 km2
Max depth = 25.3 m
Mean depth = 12.7 m
Flushing rate (ave.) = 0.23 yr -1 (23% of lake’s volume flushed per year)
Map: Dane Co. LWR Dept.
Mendota
Mendota Drainage Basin Land Use Total Area = 553 km2
59.7% 22.9%
12.0%
5.4%
Agriculture
Urban
Forest & Grasslands
Wetlands & Open Water(excludes lake area)
Lake Monona
Area = 13.7 km2
Max depth = 22.6 m
Mean depth = 8.3 m
Flushing rate (ave.) = 1.3 yr -1 (130% of lake’s volume flushed per year)
Map: Dane Co. LWR Dept.
Monona
8.1%
62.6%
23.8%
5.6%
Agriculture
Urban
Forest & Grasslands
Wetlands & Open Water(excludes lake area)
Monona Drainage Basin Land Use Total Area = 119 km2
Lake Waubesa
Area = 8.5 km2
Max depth = 11.3 m
Mean depth = 4.7 m
Flushing rate (ave.) = 4.3 yr -1 (430% of lake’s volume flushed per year)
Map: Dane Co. LWR Dept.
Waubesa
24.6%
38.8%
23.1%
13.5% Agriculture
Urban
Forest & Grasslands
Wetlands & Open Water(excludes lake area)
Waubesa Drainage Basin Land Use Total Area = 124 km2
Lake Kegonsa
Area = 13.0 km2
Max depth = 9.8 m
Mean depth = 5.1 m
Flushing rate (ave.) = 3.0 yr -1 (300% of lake’s volume flushed per year)
Map: Dane Co. LWR Dept.
Kegonsa
54.6%
18.6%
16.9%
9.8%
Agriculture
Urban
Forest & Grasslands
Wetlands & Open Water(excludes lake area)
Kegonsa Drainage Basin Land Use Total Area = 155 km2
Burke sewage treatment plant in 1920’s
Early pollution to the Yahara lakes was from Madison’s
poorly treated sewage effluent discharges!
Photo: Wisconsin State Historical Soc. archives
Dissolved Inorganic Phosphorus
Yahara Lakes, July-August 1925-2005
1925 30 35 40 45 50 55 60 65 70 75 80 85 90 95 2000 05
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
DR
P
(mg
/ L
)
Mendota
Monona
Waubesa
Kegonsa
Monona
Waubesa
Mendota
Sewage effluents:
The lower Yahara lakes had very
high inorganic P conc. when the
lakes were receiving sewage
effluent discharges
Source: Lathrop (2007)
1/18/2015
3
The Chemical Treatment Era 1925-1954
Lake Monona, 1930s
Photo: Madison Dept. Public Health
Copper Sulfate Used in the Madison Lakes
1925-1984
0
100
200
300
400
Me
tric
To
ns
Kegonsa
Waubesa
Monona
Mendota
Madison Sewage Input:
Monona Waubesa 1936 1958
Source: Lathrop (2007)
Blue-green algal blooms in Lake Mendota
first became a problem in mid-1940’s
Photo: UW-Madison Center for Limnology
Dissolved Inorganic Phosphorus in Lake Mendota Yearly Mean Conc., 1926-2012 (Oct-Sep)
P increase from
upstream
community
sewage effluents
~1945
Sewage
effluent
diversion
in 1971
High and variable P levels linked
to ag and urban runoff pollution!
Source: Updated from Lathrop et al. (1996)
Barnyards Streambanks
Uplands Urban construction sites
Sources of non-point P loadings
Photos: Dane Co. Land & Water Resources Dept.
Runoff laden with
sediment and phosphorus
P transported to lakes
during runoff events
Photos: R. Lathrop, WDNR
1/18/2015
4
Lake Mendota
Priority Watershed Project
Inventory Phase 1994-1997
Implementation Phase 1998-2008
Photo: R. Lathrop, WDNR
Many conservation
practices were
installed during the
Mendota Priority
Watershed Project
(1998-2008).
Upper: Conservation tillage
with crop residue &
sedimentation basin
Left: Grassed buffer strip
installed between cropland
and drainage ditch
Photos: Dane Co. Land & Water Resources Dept.
Left: Barynard water runoff
diversion system installation
Right: Animal lot barynard roof
installed for total confinement
feeding operation
Photos: Dane Co. Land & Water Resources Dept.
Left: Stormwater detention
pond
In urban areas…
Right: Bioretention basin with
native vegetation installed to
infiltrate stormwater
Photos: Carolyn Betz, WDNR (above); Dane Co. Land &
Water Resources Dept. (right)
Erosion control practices
were installed as a result
of Dane County’s erosion
control ordinance
Left: Construction site mulching &
erosion control fabric
Lower: Rock weeper installations
Photos: Dane Co. Land & Water Resources Dept.
Rain events >3 inches per dayMadison, Wisconsin, 1950-2009
0
1
2
3
4
5
6
7
8
9
10
1950s 1960s 1970s 1980s 1990s 2000s
Nu
mb
er
per
decad
e
Increase in large runoff events has
likely offset P load reductions from
best management practices installed
in watershed
Source: Rainfall statistics from Steve Vavrus, UW-Madison
1/18/2015
5
Sixmile Creek inlet
Pheasant Branch inlet
Yahara River inlet
Extreme runoff events
deliver massive loads of
sediment and P Lake Mendota tributary
inflows, July 9, 1993
Photos: Skot Weidemann Photography
for Dane Co. LWR Dept.
Sixmile Creek … and manure management in an
urbanizing watershed is a big problem!
Photo: Dane Co. Land & Water Resources Dept.
Some soils have very high P concentrations
• 48,700 Animal Units (AU = 1,000 lb animal) ~54% “Liquid Storage” operation AU’s
(Note: Some manure is handled as solid)
~46% “Daily Haul” solid manure operation AU’s
• 889,000 tons of livestock manure produced annually
• 1,940,000 lbs of manure P generated annually
(881,000 kg P / yr)
Manure P in Lake Mendota Watershed:
Information source (2009): Dane Co. Land and Water Resources Dept.
Photo: Carolyn Betz, WDNR
Winter manure spreading
Photo: Kurt Welke,
WDNR
March 2008
Major pollution during late winter
runoff events when ground is frozen Mendota Watershed, March 11, 2007
Photo & Data: Herb Garn, USGS
Total Phosphorus = 9.7 mg/L
Ammonium Nitrogen = 19.0 mg/L
Late winter runoff event
with high P loads… Pheasant Branch, 10 March 2013
Photo: R. Lathrop
1/18/2015
6
Percent Phosphorus Loads by Season Total for 1990-2013 (24 yrs)
Yahara River Pheasant Branch
• Late winter runoff events contributed largest seasonal P loads (44-45%)
• Spring runoff events contributed second largest seasonal loads (32-33%)
Source: R. Lathrop, UW Center for Limnology; USGS monitoring data
44.8%
31.6%
16.9%
6.6%
43.8%
32.9%
16.4%
6.9%
Jan-Mar Jan-Mar
Apr-Jun
Jul-Sep Jul-Sep
Oct-Dec Oct-Dec
Goal: “Mesotrophic” (moderately fertile) water quality
during July-August
Carlson’s (1977) Trophic State Index (TSI) for mesotrophy:
Total P <0.024 mg/L
Secchi disc >2.0 m
Mesotrophic Eutrophic
Source: Lathrop and Carpenter, 2013
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
TP
(m
g/L
) Mendota & Monona Median Total P
July-August, 1980-2012
Mendota
Monona
Mesotrophic boundary
1987-88 drought
Eutrophic
Mesotrophic
(TP = 0.024 mg/L)
Source: Lathrop and Carpenter 2013
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
TP
(m
g/L
)
Waubesa & Kegonsa Median Total P July-August, 1980-2012
Waubesa
Kegonsa
Mesotrophic
1987-88 drought
(Effect in 1988-89) Eutrophic
Mesotrophic
boundary
Source: Lathrop and Carpenter 2013
Hypereutrophic
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Secch
i (m
)
4 Yahara Lakes Median Secchi July-August, 1976-2012
Mendota
Monona
Waubesa
Kegonsa
Mesotrophy boundary(Secchi = 2.0 m)
1987-88 drought
Eutrophic
Mesotrophic
Source: Lathrop and Carpenter 2013
1/18/2015
7
Photo: Mike Kakuska
How much P loading reduction is needed for the
Yahara lakes to provide better water quality?
Periods of low P loadings during droughts
can provide useful targets
Lake outlet water is
the major source of P
load to downstream
lakes and river,
especially Waubesa
and Kegonsa.
Lake Mendota Outlet
Lake Kegonsa Outlet Photos: R. Lathrop, WDNR
Outlet P is virtually all
“biologically available”
for growing algae.
Direct drainage
P input = 29,600 kg
Outlet P
= 11,400 kg
Lake Mendota Average Annual P Loads 1976-2008
Mendota
Average Annual P Loads (kg)
Direct drainage sources 29,600
Other (atmospheric,
groundwater, etc.)
3,800
Total input load 33,400
Drought load (ave. 1987-1988)
17,400
Reduction needed to meet
drought target
−16,000
(−48%)
Outlet P load
11,400
Other P sources
= 3,800 kg
Source: Lathrop and Carpenter 2013
Direct drainage
P input = 7,500 kg
P input from
Mendota outlet
= 11,400 kg
Outlet P
= 10,400 kg
Lake Monona Average Annual P Loads 1976-2008
Average Annual
P Loads (kg)
Direct drainage 7,500
Upstream lake outlet 11,400
Other 1,100
Total input load 20,000
Drought load
(ave. 1988-1989)
11,700
Reduction to meet
drought target
−8,300
(−42%)
Outlet P load
10,400
Other P
sources
= 1,100 kg
Source: Lathrop and Carpenter 2013
Lake Waubesa Average Annual P Loads 1980-2008
Direct drainage
P input
= 2,100 kg
P input from
Monona outlet
= 10,400 kg
Outlet P
= 12,500 kg
Average Annual
P Loads (kg)
Direct drainage 2,100
Upstream lake outlet 10,400
Other 700
Total input load 13,300
Drought load
(ave. 1988-1989)
6,800
Reduction to meet
drought target
−6,500
(−49%)
Outlet P load
12,500
Other P sources
= 700 kg
Source: Lathrop and Carpenter 2013
Kegonsa
Lake Kegonsa Average Annual P Loads 1980-2008
P input from
Waubesa outlet
= 12,500 kg
Direct drainage
P input = 4,000 kg
Outlet P
= 15,200 kg
Average Annual
P Loads (kg)
Direct drainage 4,000
Upstream lake outlet 12,500
Other 1,100
Total input load 17,700
Drought load
(ave. 1988-1989)
7,100
Reduction to meet
drought target
−10,600
(−60%)
Outlet P load
15,200
Other P sources
= 1,100 kg
Source: Lathrop and Carpenter 2013
1/18/2015
8
Photo: Mike Kakuska
Goal: Reduce average annual P loads
from direct drainage sources in each of
the Yahara lakes by 50%.
(Yahara CLEAN Strategic Action Plan, November 2012)
P reductions in upstream drainage basins will produce
substantial P loading reductions to downstream lakes.
2009 SWAT modeling results by Montgomery Associates:
Resource Solutions, LLC, Cottage Grove, WI
While much work needs to
be done to reduce P loads
from agricultural lands in
Mendota’s direct drainage
basin, reducing P loads
from “hotspots” in
Kegonsa’s direct drainage
basin would also benefit
Lake Kegonsa.
Door Creek wetland 1970’s
Can Door Creek wetland’s hydrology be restored to
increase the removal of P and sediment to Lake Kegonsa?
Photo: Harvey Harper, Environmental Research and Design, Inc.
Alum treatments of lakes
• Alum treatments are done to reduce high internal P loading
from a lake’s bottom sediments when external P loading is low.
• Alum is typically applied in smaller lakes without strong water
currents that can prevent an even layer of Al floc from settling
uniformly across a lake’s bottom sediments.
Cost:
~$3-5 million
for Kegonsa?
Copper and Phosphorus Concentrations in Yahara Lake Sediments
Data source: Lathrop 2007
Little P is retained in Kegonsa’s sediments
An expensive alum
treatment would not
work in Lake Kegonsa
as little P is stored in
its deep-water
sediments and
external P loads are
very high.
Recycling is rapid in
the shallow lake with
the P rapidly flushing
downstream.
Cartoon: Bill Feeny, UW-Madison
1/18/2015
9
Massive carp hatch
Lake Waubesa, 1936 (same year as sewage
effluent into Waubesa)
Carp removal by
long seines
“Jumbo” carp Lake
Kegonsa, 1930s
Carp holding pen
Yahara River
inlet to Lake
Kegonsa, 1930s
Large carp went to
market in trucks…
… and trains
Small carp were
canned…
… or plowed under
Rough Fish Removal in the Madison Lakes
1934-1984
0
1,000
2,000
3,000
4,000
5,000
Me
tric
To
ns
Kegonsa
Waubesa
Monona
Mendota
State Removal Program (1934-1969)
Photo: E. Sievers 5 Sept. 2007
Lake Wingra restoration project A Collaboration between: Wisconsin DNR
UW Center for Limnology (LTER)
Friends of Lake Wingra
Dane County
Madison Fishing Expo
Edgewood College
UW Arboretum
City of Madison
1/18/2015
10
Alternative States in Shallow Lakes:
Clear-Water, Aquatic Plant State Turbid Algal State
Clear water
Carp absent/sparse
Aquatic plants abundant
(with high biodiversity?)
Bottom sediment resuspension &
phosphorus recycling low
Blue-green algae densities low
(Algal toxin concentrations low)
Turbid green water
Carp population dense
Aquatic plants sparse
Bottom sediment resuspension
& phosphorus recycling high
Blue-green algae densities high
(Algal toxin concentrations high?)
R. Lathrop, NALMS Symposium, 9 Nov. 2012
Radio transmitters
implanted in 14 carp to
determine location in
lake during 2006-2007
Are there times and
locations that carp
are vulnerable to
removal by seining?
Photo: R. Lathrop, WDNR
Photo: UW Center for Limnology R. Lathrop, NALMS Symposium, 9 Nov. 2012
June 12, 2006 Aug. 9, 2006
Oct. 19, 2006 Nov. 16, 2006 Feb. 20, 2007
May 10, 2006 May 25, 2006
2-Year Tracking Study:
• Carp spend most of the
open water period near
the shoreline; some
carp exhibit fidelity to
same location
• Carp periodically spawn
in Vilas lagoon in late
spring (1 of 2 years)
• Carp congregate in
deeper water in late fall
and under the ice in
winter
Maps: J. Chipman, NTL-LTER Program
Wingra Carp Removal March 2008
Commercial fishers used long
seines to capture carp in the
lake’s deep waters under the ice
Photos: D. Liebl and R. Lathrop
Photos: R. Lathrop
Lake Wingra has been
dramatically clearer
since the carp removal
in March 2008!
Vilas Beach, Lake Wingra
25 July 2008
Vilas Beach, Lake Wingra
29 July 2011
R. Lathrop, NALMS Symposium, 9 Nov. 2012
Increase in Eurasian water mifoil required macrophyte
harvesting in 2012 to afford more recreational
opportunities. This milfoil growth might also impede native
plants from spreading to deeper areas in the lake. (Lake Wingra, July 2012)
Photo: Mike Kakuska
1/18/2015
11
+5 growing seasons Pre-carp removal
+7 growing seasons
Native plants have increased while Eurasian water milfoil has declined
50
60
70
80
90
100
110
Pre Post
Me
an b
lue
gill
len
gth
(m
m)
Control (Monona)
Treatment (Wingra)
100
110
120
130
140
150
160
170
180
190
Pre Post
Me
an y
. pe
rch
le
ngt
h (
mm
)
Control (Monona)
Treatment (Wingra)
160
180
200
220
240
260
Pre Post
Me
an L
. B
ass
Len
gth
(m
m)
Control (Monona)
Treatment (Wingra)
Wingra fish community responses: Pre-carp removal (2003-2007) Post-carp removal (2008-2012) Compared to Lake Monona (control)
Source: NTL-LTER fish data
Yellow perch
Bluegill Largemouth bass
Sediment & Carp Dynamics
in the Yahara River – Cherokee Marsh System
Photo: Chin Wu, UW-Madison
Chin Wu, Richard Lathrop, Nathan Wells, Khurram Khan, Hoi Tsueng, Kurt Welke
Telemetry: Implanting Transmitter
Implanting transmitters in carp September 2010
20 carp implanted with radio transmitters
Success Rate 81%
Spring
SB MB NB 28% 56% 16%
Summer
SB MB NB 18% 61% 21%
Success Rate 75%
Fall
SB MB NB
12% 84% 4%
Success Rate 96%
Winter
SB MB NB
3% 95% 2%
Success Rate 95%
Hotspot
Rarely found
Management Priorities for Lake Kegonsa:
• Support P loading reduction practices in Mendota’s and
Monona’s drainage basins as water quality improvements in
upstream lakes will cascade downstream to Kegonsa.
• Reduce P loads from “hotspots” in Kegonsa’s direct drainage
basin.
• Determine if restoring the hydrology of the Door Creek
wetland will reduce sediment and P loads coming from Door
Creek’s watershed to Lake Kegonsa.
• Fund a DNR carp tracking study (~$20,000) to determine if a
targeted carp removal could significantly reduce carp
densities to promote clearer water and more aquatic plants
that will in turn reduce sediment resuspension, decrease
blue-green algae densities, and improve the fishery.
Recommended