using biomanipulation to achieve and sustain long … · using biomanipulation to achieve and...
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Using Biomanipulation to Achieve and Sustain Long-term Water Quality Improvements in a Shallow Lake
Brian Vlach
Rich Brasch
Alternative Stable States Theory
Turbid and Clearwater States Competing Equilibria in Shallow Lakes
• Turbid State – High algal productivity – Low rooted aquatic plant productivity – Low grazer (zooplankton) population – Higher nutrient concentrations
• Clear-water State – Robust rooted native aquatic plant community – Low algal productivity – Large grazer population – Lower nutrient concentrations
A Tale of Two Shallow Lakes
Turbid State Algal Dominated Condition
Clear-water State Plant Dominated Conditions
Overview of Cleary Lake
• Natural Environmental Lake • Surface Area = 157 acres • Watershed Area = 5102 acres • Watershed : Lake Area Ratio = 32:1 • Cleary Lake Regional Park = 1123 acres • Max Depth = 8.9 feet • Mean Depth = 2.8 feet • Classified as “shallow” lake • Listed as “impaired” by MPCA in 2008
for excessive nutrients. • Average Water Quality Conditions
June-Sept 1998-2003 Average: – Total Phosphorus = 184.2 µg/L – Chlorophyll-a = 61.4 µg/L – Secchi Depth = 1.13 m
• Turbid – Algal dominated condition
Lake Name: Cleary Lake
Lake ID: 70-002200
Surface Area 157.03 acres 63.55 hectares
Littoral Area 157.03 acres 63.55 hectares
Average Depth 2.79 ft 0.85 m
Maximum Depth 8.89 ft 2.71 m
Fetch 1.01 miles 1.63 km
23.8
0.8
11.3
0.6
17.4
25.3
13.5
7.3
Cleary Lake %Watershed Land Use
Agricultural
Farmstead
Single Family
Industrial/Commercial
Park Reserve
Undeveloped
Public Water
Wetland
LandUse Acres %
Agricultural 1213.5 23.8 Farmstead 38.8 0.8 Single Family 579.0 11.3 Industrial/Commercial 28.3 0.6 Park Reserve 888.9 17.4 Undeveloped 1292.3 25.3 Public Water 686.6 13.5 Wetland 374.4 7.3 Total 5101.8 100.0
2.5
55.8 41.6
Cleary Lake Percent Loading
Atmospheric
Watershed
Internal
Cleary Lake (70-002200)
Watershed : Lake Area Ratio: 32:1
Load
Load
lbs kg %
Atmospheric 40.6 18.4 2.5 Watershed 892.4 404.8 55.8
Internal 665.4 301.8 41.6 Total 1598.4 725.0 100
Potential Sources of Internal Load Fish Community
• Cleary Lake has a substantial population of black bullhead. Black Bullheads
have the potential to degrade water quality.
• Cleary Lake was used as a walleye rearing lake by the Minnesota Department of Natural resources prior to 1999.
• The lake has been primarily managed for pan fish (i.e. Bluegill).
• Cleary Lake had a severe fish kill in the winter of 2002-2003. The fish community was dominated by black bullheads following the winterkill.
Fish Sampled for 1999 Survey Year
Species Gear Used
Fish Caught/Net Average Fish Weight (lbs)
Sampled
Normal
Sampled
Normal
Range Range
Black Bullhead Gill Net 35 9.6-91.4 0.88 0.2-0.5
Trap Net 1.4 2.2-60.5 0.66 0.2-0.5
Bluegill Gill Net 74 NA 0.12 NA
Trap Net 95.8 1.9-29.5 ND 0.2-0.3
Green Sunfish Trap Net 2 0.2-2.0 ND 0.1-0.2
Hybrid Sunfish Trap Net 4.1 NA 0.05 NA
Largemouth Bass Trap Net 1.3 0.3-1.2 0.61 0.4-1.2
Walleye Gill Net 31 1.0-7.3 0.81 1.0-2.8
Trap Net 1.3 0.4-1.9 0.65 0.6-2.6
Normal Ranges represent typical catches for lakes with similar physical and chemical characteristics.
Potential Sources of Internal Load Anoxic and Oxic Sediment Release
• Cleary Lake is a shallow lake in an algal dominated condition. The lake did
not have a diverse native plant community to stabilize sediments and nutrients from re-suspension.
• Cleary Lake had 3 to 5 submersed native plant species from 2000-2003.
Coontail and Elodea were the dominate native plant species and have decreased in frequency of occurrence.
• Curlyleaf pondweed increased in frequency of occurrence.
Data collected and analyzed by John Skogerboe – U.S. Army Corp of Engineers.
Species
Percent Occurrence
2000 2001 2002 2003
Apr Jun Aug Apr Jun Aug Jun Aug Apr Jun Aug
Potamogeton crispus 74 85 11 54 72 4 91 0 100 94 0
Ceratophyllum demersum 61 72 83 85 72 91 61 32 43 44 32
Elodea canadensis 33 22 69 46 26 32 11 13 13 9 15
Najas flexilis 0 0 0 0 2 0 0 0 0 0 0
Potamogeton foliosus 0 0 0 0 18 0 11 0 0 0 0
Stuckenia pectinata 0 28 7 0 41 11 11 0 0 7 0
Zannichellia palustris 0 0 0 2 0 6 6 0 0 0 0
Potential Sources of Internal Load Curlyleaf Pondweed
• Curlyleaf Pondweed Senescence – The percent occurrence of curlyleaf
pondweed increased substantially from 2000-2003.
• The senescence of curlyleaf pondweed resulted in a total phosphorus spike that occurred at the end of June and the beginning of July.
• The release of nutrients from senescence and the onset of warmer water temperatures were conducive for the development of algal blooms.
Drawdown Most Desirable Option
In-lake management approach to improve water quality conditions by controlling the various sources of internal load
• Drawdown would eliminate any remaining rough fish and reduce potential water quality impacts from the fish community. Provides an opportunity to re-establish a desirable fish community.
• Drawdown would control curlyleaf pondweed by effectively freezing out the residual seed bank (turions) and reduce the potential for internal loading from senescence.
• Establish a diverse native plant community-requires the transition from algal to plant dominated condition Inhibit the growth of curlyleaf pondweed Stabilize in-lake sediments to reduce the potential for internal load
from sediment-nutrient release. Provide beneficial habitat for the aquatic community.
Outlet Structure Installation
Channel Excavation
Outlet Structure Installation 2002
Installation of outlet structure = $16,750 Excavation of outlet channel = $30,000
Lake Response to Drawdown
Annual Water Quality
Annual Water Quality
Clam Shrimp (Caenestheriella sp.)
Changes in Aquatic Vegetation
Point intercept survey was not completed in 2007.
Changes in the % Occurrence for
Curlyleaf pondweed and Submersed Natives
Changes in % Curlyleaf pondweed Occurrence relative to Snow Fall
Changes in Average Total Phosphorus Concentration
Changes in Average Chlorophyll-a Concentration and Secchi Depth
Changes in Total Phosphorus relative to % Frequency of Curlyleaf pondweed
Algal Dominated Plant Dominated
Changes in Fish Community
Fish Stocking Activity
Year Species Size Number Pounds
2004 Walleye Fry 800,000 6.8
2005 Walleye Fry 1,287,000 11.3
2006 Largemouth Bass Adults 8 6.8
2006 Bluegill Adults 100 24
Electrofishing Data 9/24/2012
Conclusions • There have been beneficial improvements in Cleary Lake water
quality and native plant community 8 years following the drawdown.
• The drawdown was effective at temporarily controlling curlyleaf pondweed. Variations in annual curlyleaf pondweed growth appear to be dependent upon snow cover.
• Clear-water conditions following the drawdown (i.e. Clam Shrimp)
was critical for establishment of a more diverse native plant community (switch from algal to plant dominated condition).
• Total phosphorus concentrations correspond with the changes in % frequency of curlyleaf pondweed during the turbid-algal dominated condition.
• Total phosphorus concentrations decreased during the clear water/plant dominated condition. Total phosphorus concentrations were stable relative to changes in curlyleaf pondweed growth.
Conclusions • The shallow lake standards for water clarity (chlorophyll-a and
secchi depth) can be met or exceeded by establishing a more diverse native plant community. However, we can’t meet the TP standard and will require additional management efforts (i.e. watershed or alum).
• The public perception is that there have been minimal
improvements in the water quality. Managing shallow lakes to the MPCA state standards supports the “plant dominated condition” to improve water quality. There needs to be better education for the general public with regards to water quality expectations when dealing with shallow lakes.
Acknowledgments
• Minnesota Department of Natural Resources • Gerald Johnson • Daryl Ellison
• Minnesota Pollution Control Agency
• Chip Welling
• U.S. Army Corp of Engineers • John Skogerboe
• Three Rivers Park District
• John Barten • James Johnson • Dean Almquist
Managing Curlyleaf Pondweed with
Herbicides: Experiences with Whole
Lake and Partial Lake Treatments
Minnesota Water Resources Conference October 17, 2012
Yvette Christianson, MS
Steve McComas, MSCE
Udai Singh, Ph.D., PE
Kelly Dooley, MS
Gleason Lake Cities:
•Plymouth (95%) •Wayzata •Orono •Minnetonka
•160 Acre •Main Lake Area: 129 acres •North Basin Area: 31 acres
•Average to poor water quality
•Gleason Lake Improvement Association (GLIA) formed in 1980
Gleason Lake
Curlyleaf pondweed (Potamogeton crispus)
Early season maturation Crowds out native plants Hinders recreational
activities Contributes to high
internal phosphorus
Gleason Lake Management Program Study design:
2007-2009: 3 years of whole lake herbicide treatment 2010-2012: 3 years of herbicide spot treatment
Funding Agreement
MCWD GLIA 2007 Surveys, Herbicide Application, Fees $6,000.00 contribution 2008 Surveys, Herbicide Application, Fees $6,000.00 contribution 2009 Surveys, Herbicide Application, Fees $6,000.00 contribution 2010 Surveys Herbicide Application, Fees 2011 Surveys Herbicide Application, Fees 2012 Surveys Herbicide Application, Fees
Gleason Lake Objectives Determine if herbicide treatments with Aquathol® K can
control and manage for curlyleaf pondweed
Gleason Lake Objectives Determine if herbicide treatments are a viable long-term
solution for Gleason Lake
•Selected certified contractor to apply the herbicide treatment.
Methods: Project Steps
•Obtained signatures from the homeowners
•Applied for MNDNR Permit
•Monitored the water temperature (50°-60° F optimal temps for herbicide effectiveness)
•128 locations on Main lake •31 locations on North Bay
Method: Point Locations for the Aquatic Plant Survey
Methods: Curlyleaf Abundance Density Scale
Rake Density: 4
Rake Density: 1 Rake Density: 2
Rake Density: 3
Stem Densities were determined by counting the number of curlyleaf stems within a 0.10 m² quadrat.
Methods: Curlyleaf Stem Density
Lake Sediment Characteristics: •pH •Fe:Mn Ratio •Bulk Density •Organic Matter
Curlyleaf pondweed growth was predicted to produce mostly moderate growth
Methods: Lake Sediment Samples
Methods: Fish & Macroinvertebrate Survey
Methods: Lake Water Quality Monitoring YSI multi-probe sonde measures:
Water temperature Dissolved Oxygen pH Conductivity
Nutrients: Total Phosphorus Soluble reactive phosphorus Total Nitrogen
Algal abundance: Chlorophyll-a
• Water transparency: Secchi disk depth
Ions: Chloride
2007 2008
2009 2010 2011
Results: Curlyleaf Pondweed Distribution (spring surveys)
Green circles = light growth
Yellow circles = moderate growth
Red circles = heavy growth
2012
Results: Curlyleaf Stem Densities Prior to Herbicide Treatment
2007: 817 stems/m2 2008: 411 stems/m2 2009: 329 stems/m2
2010: 73 stems/m2 2011: 21 stems/m2 2012: 77 stems/m2
Results: Curlyleaf Pondweed Stem Densities
817
411 329
73 21
77
0
100
200
300
400
500
600
700
800
900
2007 2008 2009 2010 2011 2012
Ste
ms/m
²
2007* 2008* 2009* 2010 2011 2012
Acres Treated 137 137 140 27.9 16.3 45 Gallons of
Herbicide 521 521 517 98 39 164 *Whole lake treatments
Results: Herbicide Treatment History
Results: Native Vegetation Gleason Lake
Coontail
Gleason Lake August
Coontail 2007-2012
2007 2008
2009 2010 2011
Green squares = light growth
Yellow squares = moderate growth
Red squares = heavy growth
2012
Results: Annual Mean Secchi Disk Depth
1.08 0.91
0.77
1.11 1.23 1.24
1.38
1.93
0.00
0.50
1.00
1.50
2.00
2.50
2005 2006 2007* 2008 2009 2010 2011 2012
Se
cc
hi D
isk
De
pth
(m
)
*Began herbicide treatment
Results: Annual Mean Total Phosphorus
116
133 125
96 105
65
50 41
0
20
40
60
80
100
120
140
2005 2006 2007* 2008 2009 2010 2011 2012
To
tal P
ho
sp
ho
rus
(µ
g/L
)
*Began herbicide treatment
Results: Annual Mean Chlorophyll A
61 53
60
69
52
37 29
14
0
10
20
30
40
50
60
70
80
2005 2006 2007* 2008 2009 2010 2011 2012
Ch
lA (
µg
/L)
*Began herbicide treatment
Did We Meet Objectives? Determine if herbicide treatments with Aquathol® K can
control and manage for curlyleaf pondweed
2007
Yes
2012
Did We Meet Objectives? Determine if herbicide treatments are a viable long-term
solution for Gleason Lake:
•Native Vegetation
•Water Transparency
•Phosphorus Concentrations •Chlorophyll a Concentrations
Yes, but
Other Factors: •Increased size of storm pond •Aerated during winter
Post Project Gleason Lake Improvement Association plans to continue
applying spot treatments each spring MCWD will continue monitoring Gleason Lake to see if
the lake’s water quality continues to improve
MCWD/Blue Water Science will analyze fish and macroinvertebrate data
Lake residents concerns over increase in coontail may lead to additional vegetation management projects
Thanks to our partners & consultants:
Questions?
Yvette Christianson, Water Quality Specialist Minnehaha Creek Watershed District [email protected]
www.minnehahacreek.org
Acres Treated for Curlyleaf
2011 2012 2010
28 Acres 16 Acres 45 Acres
References Emmons and Olivier Resources. 2003. Gleason
Lake Management Plan.
McComas, Steve and Jo Stuckert, 2009. Curlyleaf Pondweed and Eurasian Watermilfoil Growth Potential Based on Gleason Lake Sediment Characteristics.
McComas, Steve and Jo Stuckert, 2011. Aquatic Plant Surveys for Gleason Lake, Hennepin, Co, Minnesota for 2011.
Endothall Herbicide General purpose aquatic herbicide. Some other trade names for the acid form of
Endothall include: Aquathol, Hydrothal-47, Hydrothal-191
Trade names for Disodium salt of Endothall include: Accelerate, Des-I-Cate, Tri-endothal, Ripenthol, Niagrathol.
LD50 is much higher then the doses used for lake treatment.
Half life 7-21 days in soil and 4 to 7 days in water.
Vegetation in Gleason Lake
Coontail Curly-leaf pondweed
White water lilies
Elodea Duckweed & Watermeal Filamentous Algae
Results: Water Quality Annual Averages Years
Average Secchi
Disk Depth (m)
Average Total
Phosphorus (µg/L)
Average
Chlorophyll-a
(µg/L)
2005 1.08 116.33 62.72 2006 0.91 133.29 53.06 2007* 0.77 125.29 59.83 2008 1.11 95.56 69.44 2009 1.23 109.60 54.50 2010 1.24 65.44 36.89 2011 1.38 48.78 27.11 2012
*First year of Aquathol K treatment