The East Pond Alum Treatment
A Multi‐Stakeholder Approach to Lake Management
Dr. Danielle WainLake Science Director, 7 Lakes Alliance
Charlie BaederDirector of Programs, 7 Lakes Alliance
Dr. Whitney KingMiselis Professor of Chemistry, Colby College
The Belgrade Lakes
6
2
3
1
4
5
7
1 = East Pond2 = North Pond3 = Great Pond4 = McGrath Pond5 = Salmon Lake6 = Long Pond7 = Messalonskee Lake
SA = 700 ha (1700 acres)Max depth = 8 mMean depth = 5.5 m
Watershed area = 1100 haWA:SA = 1.6Residence Time = 4 yrs
Historic East Pond Water Temperature Trends
23C
27C
Dot size proportional to number of observations in that year
Data below from Maine DEP, Lake Stewards of Maine
30%
50%
Maximum measured surface temperature is increasing, as is stratification strength
Data has a bias towards the summer, which needs to be kept in mind
For years with n > 6 profiles
Historic East Pond Water Quality Trends Data below from Maine DEP, Lake Stewards of Maine
23 ppb
28 ppb
More stratification leads to more anoxic events, but we don’t always capture these in sampling!
While there is a trend in phosphorus as well, the Secchi data show the increase in blooms more clearly
3 mg/L
6 mg/L
The minimum DO observed in a given year
Phosphorus Release
Cautionary Tale – Rapid Change is Possible!
1988
5
Pristine Lake
Al(III)‐P
Al(III)Al(III)
Al(III)Al(III)
Al(III)Al(III)
Al(III)Al(III)‐P
Fe(III) Fe(III)
Wind
Fe(III)‐P
“Outflow”
Epilimnion (top of the lake)
Hypolimnion (bottom of the lake)
“Inflow”
A
B
CLow in Carbon
thermocline
Impacted Lake
Al(III)‐P
Fe(III)Fe(III)
Fe(III)Fe(III)
Fe(III)Al(III)
Fe(III)Fe(III)‐P
Fe(III) Fe(III)
Fe(III)‐P
Fe(II) Fe(II)Fe(II)
PO43‐
PO43‐
PO43‐
Epilimnion
Hypolimnion
“Inflow” “Outflow”
A
B
CHigh in Carbon
Wind
Al(III)‐PAl(III)
Phosphate retention mechanisms
• East Pond’s lake sediment has naturally present iron (III) and aluminum (III)• Both compounds are good Lewis acids, and bind to phosphate compounds, which controls the amount available to cyanobacteria
• Fe(OH)3 + PO4‐3 Fe(OH)3 * PO4(s)
• Al(OH)3 + PO4‐3 Al(OH)3 * PO4(s)
• However, not all Lewis acids are equally effective
Wagner, K. J. The practical guide to lake management in Massachusetts: a companion to the final generic environmental impact report on eutrophication and aquatic plant management in Massachusetts; Commonwealth of Massachusetts, Executive Office of Environmental Affairs: Boston, 2004.
Amirbahman A, Lake BA, Norton SA (2012) Seasonal phosphorus dynamics in the surficial sediment of two shallow temperate lakes: a solid‐phase and pore‐water study. Hydrobiologia701:65–77. doi: 10.1007/s10750‐012‐1257‐z
Redox Reactions (Pourbaix plots)
StummW, Morgan JJ (1996) pε‐pH, potential‐pH diagrams. In: Aquatic Chemistry: Chemical Equilibria and Rates in Natural Waters, 3rd edn. Wiley‐Interscience publication, Canada, pp 458–461
How To fix this problem2Al(OH)3 Al2O3 * H2O + 2H2O
Roberge PR Aluminum E‐pH (Pourbaix) Diagram. In: Corrosion Doctors. https://corrosion‐doctors.org/Corrosion‐Thermodynamics/Potential‐pH‐diagram‐aluminum.htm. Accessed 5 Dec 2018
GOALS
The goal is to eliminate annual algal blooms on East Pond, and to restore water quality.
Although “external” loading from erosion and septic systems contribute to East Pond’s algal problems, “internal” in‐lake sediments must also be treated to eliminate algal blooms.
Forty years of data, together with Colby’s extensive water and sediment sampling and analysis in 2015‐2017, provided the information needed to recommend the management actions needed to reduce algal blooms on East Pond.
Ken Wagner, PhD – Loading Analysis – April 2017
PrecipitationGroundwaterWatershed (External)WaterfowlInternal
Steering Committee: East Pond Association; Colby College; Ken Wagner, PhD; Towns of Oakland and Smithfield; camp owners; Kennebec County Soil & Water Conservation District; Ecological Instincts; Belgrade Regional Conservation Alliance and Maine Lakes Resource Center (now 7 Lakes Alliance)
Sub‐Committees:• Science• Fundraising• Communications
Communications• “Recurrent” algal blooms• Will get worse over the next 10 years• Self‐sustaining algal cycles• Will become more costly• We can fix it now• 80% internal load reduction• “Probability high that the lake will be
substantially better for a long time”
Fundraising Committee
• $ 1.1 million project• $ 600,000 – local share needed for match• Major donors, lake residents, Maine DEP,
Foundations, 7 Lakes, Colby College
It is up to us, we all have to participate
East Pond Alum Project ‐ 2018• 2 Phases
• June 2018 and October 2018• 25g/m2 in June• 20 g/m2 in October• Total 45 g/m2 applied to 676 acres (lake area over 5 meters depth)• Required for camp owners who were major donors to the project• Allowed us to do additional fundraising during summer 2018• Allowed us to demonstrate the results of the initial June treatment to lake residents
• “So happy with results so far!! Another test ‐ our daughter who is highly allergic to the algae is enjoying allergy free swimming in August for the first time in about 20 YEARS!” (August 2018)
45.00 g/m2 Dose676.00 acres Area135.70 tons Al401.48 lb Al/acre
364,278.00 gallons @ 45g/m282.00 tank trucks
East Pond Alum Project ‐Metrics
Alum Project Costs Funding Mar‐191,006,220 SOLitude contract 525,000 Fundraising to date
7,500 Road 232,000 US EPA/Maine DEP 319 CWA20,000 Wagner‐consultant 200,000 Harold Alfond Foundation20,000 7 Lakes management 957,000 Cash in Hand10,000 Monitoring 120,000 Pledges9,500 Interest 1,077,000 Total to date
1,073,220
What You Can Do
• Campaign for doing things to protect the lake• Convince your neighbors• Be an ambassador for the lake• Be a lake steward• Give a handout to your neighbors, your relatives • Campaign for doing things to protect the lake• Treat the lake as a partner in your quality of life• “We have a solution” that will benefit everybody
Alum: Better living through chemistry?
Summary
• East Pond had been suffering from algal blooms for over two decades• Historic input of P from when the watershed was agricultural• Despite intensive watershed work and biomanipulation, East Pond continued to bloom
• Needed a different solution!• Extensive work was done to determine the proper alum dosing• Alum is relatively quick fix that appears to be working well – but we are pushing the known limits of such treatments!
Acknowledgements
East Pond Association (150 private donations)
Betsy and Jerry Tipper
Abbey Sykes ’21 and Guillermo Picó Oms ‘19
2018 Belgrade Lakes summer research group
Harold – Alfond Foundation
US EPA and Maine DEP
Team Alum 2018
Footage by Tim Stonefield
Ken Wagner