Prepared by the Great Lakes Water Quality Agreement Nutrients Annex Subcommittee
-------
Lake Erie Binational Phosphorus
Reduction Strategy
June 2019
Prepared by the Great Lakes Water Quality Agreement Nutrients Annex Subcommittee:
Environment and Climate Change Canada (co-lead)
U.S. Environmental Protection Agency (co-lead)
Agriculture and Agri-Food Canada
Chiefs of Ontario
Conservation Ontario
Indiana Department of Environmental Management
Michigan Department of Agriculture and Rural Development
Michigan Department of Environmental Quality
National Oceanic and Atmospheric Administration
New York Department of Environmental Conservation
Ohio Department of Agriculture
Ohio Environmental Protection Agency
Ontario Ministry of Agriculture, Food and Rural Affairs
Ontario Ministry of the Environment, Conservation and Parks
Ontario Ministry of Natural Resources and Forestry
Pennsylvania Department of Environmental Protection
U.S. Department of Agriculture
U.S. Geological Survey
Cover photo: NOAA, 2017
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Lake Erie Binational Phosphorus Reduction Strategy
Table of Contents
Preface 3
Acknowledgements 4
1 Assessment of environmental conditions 5
1.1 Background 5
1.2 Lake Erie's three basins 6
1.3 Conditions are deteriorating 8
1.4 Phosphorus: the limiting nutrient 10
2 Update to Binational Phosphorus Targets, 2016 13
2.1 Lake Ecosystem Objectives 13
2.2 Phosphorus targets to meet LEOs 14
2.3 Load Reduction Target Allocations by Country 17
3 Binational Priorities for Implementation 18
3.1 Priority Tributaries for Nutrient Control 18
3.2 Binational Strategies to Support Domestic Actions 21
Strategy #1: Reduce Phosphorus Loadings from Agricultural Sources 21
Strategy #2: Reduce Phosphorus Loadings from Municipal Sources 22
Strategy #3: Support Watershed Based Planning and Restoration Efforts 22
Strategy #4: Coordinate Science, Research and Monitoring 23
Strategy #5: Enhance Communication and Outreach 23
4 Tracking and communicating progress towards the targets 24
4.1 Adaptive Management 24
4.2 Reporting 25
4.3 Expected Outcomes 26
4.4 Conclusion 26
Glossary 27
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2
Lake Erie Binational Phosphorus Reduction Strategy
List of Figures and Tables
FIGURE 1: Watershed Stressors 5
FIGURE 2: Lake Erie Watershed and Bathymetry 7
FIGURE 3: Temporal variation in Bloom Severity Index 8
FIGURE 4: Total phosphorus concentrations in the Great Lakes,
as measured during spring surveys in 2013 and 2014 10
FIGURE 5: Annual loads of total phosphorus to Lake Erie from Canada and the U.S 12
FIGURE 6: Annual spring SRP loads and 5-year running averages for the Maumee River 12
TABLE 1: Binational Phosphorus Load Reduction Targets 15
FIGURE 7: Watershed map of the Lake Erie priority triPutaries for nearshore algae Plooms 16
TABLE 2: Target Allocations by Source 17
FIGURE 8: Average annual total phosphorus loads 2003-2013 19
FIGURE 9: Lake Erie Priority Tributaries for Nutrient Control 20
TABLE 3: Lake Erie Nutrients - Summary of Public Reporting 25
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Lake Erie Binational Phosphorus Reduction Strategy
Preface
To combat the growing threat of toxic and nuisance algal development and the expansion
of zones of low oxygen (hypoxia) in Lake Erie, the United States and Canada committed,
through the 2012 Great Lakes Water Quality Agreement, to review and update binational
phosphorus load reduction targets for Lake Erie by February, 2016.
In response to this commitment, following a robust
binational science-based process and extensive
public consultation, Canada and the U.S. adopted
the following phosphorus reduction targets
(compared to a 2008 baseline) for Lake Erie
on February 22, 2016:
To minimize the extent of hypoxic zones in
the waters of the central basin of Lake Erie,
a 40 percent reduction in total phosphorus
(TP) entering the western and central basins
of Lake Eriefrom the United States and
from Canadato achieve an annual load of
6,000 metric tons to the central basin. This
amounts to a reduction from the United States
and Canada of 3,316 metric tons and
212 metric tons respectively.
To maintain algal species consistent with
healthy aquatic ecosystems in the near-
shore waters of the western and central
basins of Lake Erie, a 40 percent reduction
in spring TP and soluble reactive phosphorus
(SRP) loads from the following watersheds
where algae is a localized problem:
- in Canada: Thames River and Leamington
tributaries, and;
- in the United States: Maumee River, River
Raisin, Portage River, Toussaint Creek,
Sandusky River and Huron River (Ohio).
To maintain cyanobacteria biomass at
levels that do not produce concentrations
of toxins that pose a threat to human or
ecosystem health in the waters of the
western basin of Lake Erie, a 40 percent
reduction in spring TP and SRP loads from
the Maumee River in the United States.
With the adoption of new binational targets in
place, the governments promptly began working
with partners and stakeholders to develop domestic
action plans (DAPs). These plans, which outline
strategies for meeting the new targets in specific
jurisdictions and watersheds, were published
in 2018. Further work to establish targets that
will minimize impacts from nuisance algae in the
eastern basin of Lake Erie continues, and will be
reviewed in 2020.
-------
The purpose of this Lake Erie Binational Phosphorus
Reduction Strategy is to descriPe the framework
for Pinational cooperation under the GLWQA
Nutrients Annex towards the achievement of the
2016 Pinational phosphorus reduction targets.
The strategy has four components:
1. An updated assessment of environmental
conditions to guide lakewide nutrient
management in Lake Erie (the last
assessment was completed in 2011.1);
2. A summary of the process used to develop
the 2016 targets and allocate load reductions
Petween the U.S. and Canada;
3. Binational priorities for implementation of
measures to manage phosphorus loading,
including the identification of watersheds that
are a priority for nutrient control and Pinational
priorities for research and monitoring; and
4. A description of how progress will Pe tracked
using an adaptive management approach.
The Lake Erie Binational Phosphorus Reduction
Strategy will Pe reviewed every 5 years, which
also aligns with the frequency of DAP reviews. The
Strategy will Pe updated as needed, to reflect sig-
nificant changes to the targets, country allocations
and/or Pinational priorities for implementation.
Acknowledgements
The Great Lakes Water Quality Agreement Nutrients Annex SuPcommittee would like to acknowledge
the contriPutions of its OPjective and Targets Task Team to this strategy through the development of
ecosystem oPjectives and phosphorus loading reduction targets for Lake Erie. The Great Lakes Water
Quality Agreement Nutrients Annex SuPcommittee would also like to acknowledge the contriPutions of
our stakeholders and partners in moving the agenda forward, reviewing and commenting on the work
of the SuPcommittee and its Task Teams.
1 Lake Erie LaMP. 2011. Lake Erie Binational Nutrient Management Strategy: Protecting Lake Erie by Managing Phosphorus.
Prepared by the Lake Erie LaMP Work Group Nutrient Management Task Group.
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Lake Erie Binational Phosphorus Reduction Strategy
Assessment of
environmental
conditions
1
1.1 Background
Excessive algal blooms in the 1960s and 1970s
were a major driver for the signing of the first
Great Lakes Water Quality Agreement (GLWQA)
in 1972. In that Agreement, the Governments of
Canada and the U.S. agreed to reduce phosphorus
loads to Lake Erie by more than 50 percent (from
29,000 to 14,600 metric tons per year). In the
subsequent 1978 Agreement, the two countries
FIGURE 1: Watershed Stressors
agreed to further reduce phosphorus loads
to Lake Erie to 11,000 metric tons per year.
Regulation of phosphorus concentrations in
detergents, investing in sewage treatment, and
developing and implementing best management
practices on agricultural lands succeeded in
reducing the loads to target levels, and algal
blooms in Lake Erie decreased significantly
throughout the 1980s. However, in the late 1990s,
despite ongoing efforts to limit phosphorus dis-
charges to Lake Erie, toxic and nuisance algal
blooms began to increase.
&
'V
A
Low Stress
High Stress
Relative and combined stress of each watershed to the Great Lakes nearshore areas.
Red areas are identified as high stress, green as low stress and degrees of yellow as moderate stress.
Source: Great Lakes Environmental Indicators (GLEI) Project, University of Windsor and University of Minnesota - Duluth, 2015.
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6 Lake Erie Binational Phosphorus Reduction Strategy
Lake Erie is susceptible to excessive algal growth,
in part, due to its physical characteristics. As the
smallest of the Great Lakes by volume, Lake Erie
is also the shallowest and is located in the south-
ernmost portion of the Great Lakes basin, making
Lake Erie waters the warmest and the most bio-
logically productive of all the Great Lakes. Lake Erie
is also exposed to the greatest stress from urbaniza-
tion, industrialization and agriculture, and is the most
populated of the Great Lakes, serving a population
of over 11 million. Lake Erie: 1) receives the high-
est loads of phosphorus of all the Great Lakes;
2) surpasses all the other Great Lakes in the amount
of effluent received from sewage treatment plants;
and 3) is most subject to sediment loading due to
the nature of the underlying geology and land use.
1.2 Lake Erie's three basins
Water moves through Lake Erie relatively quickly.
Lake Erie has the shortest residence time of the
Great Lakes: on average, water is replaced in
Lake Erie every 2.7 years (by way of comparison,
water replacement in Lake Ontario takes 6 years,
and in Lake Superior it takes 173 years). Most of
the water enters through the western basin of the
lake, where it quickly (in a matter of days) flows
into the central basin. From there, water moves
through the eastern basin and eventually flows
into Lake Ontario.
Along the way, nutrients and algae interact in
unique ways in each of Lake Erie's three dis-
tinct basins. The western basin receives about
61 percent of the lake's entire annual total
phosphorus load, while the central basin and
eastern basin receive 27 percent and 12 percent,
respectively. Differences in the types and/or
densities of algae growing in each basin are due
to differences in lake depth, water temperature,
substrate, and the local influence of tributaries.
The Western Basin is very shallow, with an average
depth of 7.4 meters (24 feet) and a maximum depth
of 19 meters (62 feet). It is warm, and it receives
most of the lake's total phosphorus load because
of the size of the Detroit and Maumee Rivers. As a
result, algal blooms dominated by the blue-green
alga (cyanobacteria) Microcystis aeruginosa occur
regularly, fouling shorelines during the spring,
summer and fall. This species can form blooms
that contain toxins (e.g., microcystin) dangerous
to humans and wildlife.
The Central Basin is deeper with an average
depth of 18.3 meters (60 feet) and a maximum
depth of 25 meters (82 feet). Algal blooms that
originate in the western basin often move into
the central basin, as well. Blooms also form at
the mouth of the Sandusky River, which delivers
the third highest tributary load to the lake overall.
Excess phosphorus also contributes to hypoxic
(low-oxygen) conditions in the cold bottom layer
of the lake (the hypolimnion) when algae die and
decompose. This decomposition uses up the oxy-
gen during the summer, leaving little to none for
the aquatic community which suffocates or moves
elsewhere, creating Lake Erie's "Dead Zone."
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Lake Erie Binational Phosphorus Reduction Strategy
7
The Eastern Basin is the deepest of the three
basins with an average depth of 24 meters
(80 feet) and a maximum depth of 64 meters
(210 feet). While the phosphorus levels in the
eastern basin are generally much lower than
the western and central basins, levels are still
high enough to promote the excessive growth
of Cladophora. Cladophora is filamentous green
algae that grows on hard substrates in all of the
Great Lakes. Cladophora is not toxic, but it is a
nuisance and can pose threats to human health.
Beyond clogging water intakes and degrading fish
habitat, odorous rotting mats of Cladophora on
beaches encourage the growth of bacteria and
are a factor in beach closures. The presence of
Cladophora may create an environment conducive
to the development of botulism, which results in
bird and fish deaths.
Lake Erie
Lake Erie watershed
International border
MICHIGAN
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London
NEW YORK
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210
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Cold oxygen-poor water
FIGURE 2: Lake Erie Watershed and Bathymetry
Source: Environment and Climate Change Canada, 2015.
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Lake Erie Binational Phosphorus Reduction Strategy
1.3 Conditions are
deteriorating
Toxic and nuisance aigal bloom occurrences in
Lake Erie have increased over the past decade,
with record-setting blooms occurring in 2011 and
2015. The blooms threaten drinking water, increase
costs associated with drinking water treatment
needs, and occasionally force closures of treatment
plants. They clog water intake systems, adversely
impact commercial and recreational fishing activities
and other recreational pursuits, and degrade fish
and wildlife habitat and populations.
In 2011, concentrations of the algal toxin
microcystin in the open waters of the western
basin of Lake Erie were 50 times higher than the
World Health Organization (WHO) limit for safe
body contact, and 1,200 times higher than the
limit for safe drinking water. In August 2014, algal
toxins forced closure of the Toledo, Ohio drinking
water treatment plant, and private water users on
Pelee Island, Ontario, were warned not to bathe in,
or drink, Lake Erie water. These incidents affected
more than 500,000 people.
10
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CD
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o
o
Western Lake Erie
Harmful Bloom Severity
8 -
£ 6-
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2002 2004 2006 2008 2010 2012 2014 2016 2018
FIGURE 3: Temporal variation in Bloom Severity Index
Source: National Oceanic and Atmospheric Agency, 2018
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Lake Erie Binational Phosphorus Reduction Strategy 9
Other signs of nutrient enrichment (eutrophication)
in the lake include excessive nuisance algal growth in
nearshore areas, and depletion of oxygen in Pottom
waters (created when algae die and decompose).
Some of the hypoxia oPserved in the central Pasin
is a natural phenomenon; however, since the
early 2000s, the hypoxic (low-oxygen) area in the
central Basin of Lake Erie has increased to aPout
4,500 km2, on average, with the largest hypoxic
event of 8,800 km2 occurring in 2012. Hypoxic
conditions can affect the growth and survival of fish
species. In 2012, hypoxic conditions were respon-
siPle for tens of thousands of dead fish washing
up on a 40 km stretch of shoreline Petween Erieau
and Port Stanley, Ontario. In addition, Peginning in
the early 2000s, mats of Cladophora in the eastern
Pasin of Lake Erie have caused Peach fouling,
undesiraPle odors from decomposing Cladophora,
clogged industrial intakes and degraded fish haPitat.
In summary, the lake is responding to high levels
of nutrients in three negative ways, each of which
appears to Pe intensifying. The three key nutrient
issues to Pe addressed are: 1) the increasing
frequency and extent of harmful algal Plooms and
associated toxins; 2) the decreasing availaPility of
oxygen in the hypolimnetic waters in the central
Pasin; and 3) the increasing growth of nuisance
algae, like Cladophora, on the lake Pottom.
The resurgence of harmful and nuisance algal
Plooms in Lake Erie is the result of complex
interactions among multiple factors rather than
one specific factor.
Data collected Py Environment and Climate
Change Canada and the U.S. Environmental
Protection Agency show that, while phosphorus
concentrations in the lake can Pe highly variaPle,
the concentrations in the western and central
Pasins consistently exceed the levels commensur-
ate with a healthy ecosystem. Furthermore, in-lake
nutrient cycling has changed due to the spread of
invasive zePra and quagga mussels that Pecame
estaPlished in the lake in the 1990s. Invasive
mussels retain and recycle nutrients in nearshore
areas Py filtering particles from the water column
and suPsequently excreting highly PioavailaPle
phosphorus as a waste product. This alteration of
nutrient flows is resulting in greater nuisance algal
growth, such as Cladophora, in the nearshore
regions, closer to where humans interact with the
lake. Other changes contriPuting to the resur-
gence of algae include the loss of wetlands and
riparian vegetation that once trapped nutrients, as
well as release of sediment-Pound residual (legacy)
phosphorus from soils. Effects of climate change
are also impacting nutrient concentrations. For
example, increasing temperatures in recent years
are creating longer growing seasons for algae, and
more frequent high-intensity precipitation events
during the spring are delivering nutrients during a
time of year that is critical for promoting the inten-
sity and duration of summer algal Plooms. Add
the intensification of land use to these factors and
changes in land management, such as increases
in fall application of fertilizers, or increases in
urPan runoff due to more hard surfaces, and it is
clear that the comPination of multiple factors are
increasing the amount of phosphorus entering
Lake Erie from land runoff and point sources.
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Lake Erie Binational Phosphorus Reduction Strategy
1.4 Phosphorus:
the limiting nutrient
Phosphorus is a naturally occurring and biologically
active element that is a component of all biological
tissue. It is an essential nutrient for plant and animal
life, making it necessary for maintaining a healthy
lake ecosystem.
Total phosphorus is a combination of dissolved and
particulate forms. Particulate phosphorus is bound
to soil particles and is readily transported by water
and wind erosion, but is much less bioavailable and
is less accessible to plants and algae. The dissolved
form (known as "soluble reactive phosphorus") is
highly bioavailable and rapidly taken up by plants.
High levels of soluble reactive phosphorus in water
promote rapid growth of algae.
FIGURE 4: Total phosphorus concentrations in the Great Lakes,
as measured during spring surveys in 2016 and 2017
Source: Environment and Climate Change Canada, and United States Environmental Protection Agency, 2019.
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Lake Erie Binational Phosphorus Reduction Strategy
Phosphorus is the nutrient limiting algal growth in
Lake Erie and is the focus of binational nutrient
management efforts under the GLWQA. While
many other nutrients are present in water, such
as nitrogen, silica, carbon, and even trace metals,
these nutrients are considered to be only second-
arily or seasonally limiting. Consequently, actions
limiting phosphorus loading from the surrounding
watersheds are currently the primary strategy to
address the problems associated with excessive
algal growth. However, there is increasing evi-
dence that both nitrogen and phosphorus should
be considered as part of a more comprehensive
nutrient management strategy to control harmful
algal blooms. While the current strategy is focused
on phosphorus reduction, the effects of nitrogen
and other nutrients continue to be researched and
monitored so that management decisions and
actions can be adapted, if required.
Phosphorus enters Lake Erie from point sources,
such as treated effluent from municipal wastewater
treatment facilities, as well as nonpoint sources
(NPS) such as runoff from urban and agricultural
landscapes. These sources contain a mixture of
soluble reactive phosphorus and particulate phos-
phorus, with the proportion of each dependent
on the particular activity and geographic location.
Phosphorus naturally cycles through air, water
and soil and can change forms many times before
it reaches Lake Erie, as well as once it is within
the lake. Phosphorus is stored in and released
from biological tissues and mineral particles in
soils and sediments on lake and stream bottoms,
flood plains, urban water systems and agricultural
fields. These "legacy" sources of phosphorus can
be re-mobilized and thus add to loadings even
when current practices are geared to phosphorus
reduction. Actions to reduce phosphorus over time
will help reduce the amount of legacy phosphorus
available to the Lake Erie ecosystem.
Some sources of phosphorus (such as human
sewage, animal manures, and fertilizers) are very
high in soluble reactive phosphorus, and thus
highly bioavailable. Controls of these sources
can involve containment (e.g., manure storage)
and often specialized treatment (e.g., wastewater
treatment plants). Effective control of non-point
sources can be more complex and requires par-
ticular attention to preventive actions (e.g., right
source, right timing, placement, and rate of manure
and fertilizer application) in addition to addressing
hydrological factors in the landscape.
Overall, monitoring has shown that despite
significant year-to-year variation in loads, the
average annual amount of total phosphorus
entering the lake has been relatively stable
over the past 15 years. What appears to have
changed however is that there has been a
significant increase in the proportion of the
phosphorus load to Lake Erie that is in dissolved
form, as opposed to particulate form. The timing
of when phosphorus is delivered to the lake is
critical, as well. Non-point source runoff from the
Maumee River during the spring period (March to
June) has been shown to be the best predictor
of cyanobacteria bloom biomass each year.
Therefore, reductions in total phosphorus and
soluble reactive phosphorus, especially under
high flow conditions, are necessary to combat
nutrient related problems in Lake Erie.
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Lake Erie Binational Phosphorus Reduction Strategy
FIGURE 5: Annual loads of total phosphorus to Lake Erie from Canada and the U.S.
30,000
25,000
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Lake Erie Binational Phosphorus Reduction Strategy
Update to Binational
Phosphorus Targets, 2016
2
To combat the growing threat of toxic and nuis-
ance algal development and the expansion of
zones of low oxygen (hypoxia) in Lake Erie, the
United States and Canada committed, through
the 2012 Great Lakes Water Quality Agreement,
to review and update binational phosphorus load
reduction targets for Lake Erie by February, 2016.
In response to this commitment, Environment and
Climate Change Canada and U.S. EPA convened
a GLWQA Nutrients Annex Subcommittee in
2013, made up of representatives of federal,
state, and provincial governments, Indigenous
organizations, municipal and local governments,
and other key partners, to review the interim
phosphorus targets for Lake Erie, and to rec-
ommend revisions to those targets (if required).
The Subcommittee engaged over 30 scientific
experts on a binational workgroup (named the
"Objectives and Targets Task Team") to do this
work. The Task Team's full technical report can be
accessed here: https://binational.net//wp-content/
uploads/2015/06/nutrients-TT-report-en-sm.pdf.
Following a robust binational science-based
process and extensive public consultation, Canada
and the U.S. adopted phosphorus reduction targets
for the western and central basins of Lake Erie
on February 22, 2016. Further work to establish
targets that will minimize impacts from nuisance
algae in the eastern basin of Lake Erie continues,
and will be reviewed in 2020.
2.1 Lake Ecosystem
Objectives
Algae are an essential component of Lake Erie's
ecosystem. The goal is to identify and achieve
the right level and type of algal growth to support
a healthy and productive ecosystem.
The 2012 Agreement provides guidance in relation
to what constitutes a healthy and productive
ecosystem that is free from human induced
eutrophication symptoms. There are six Lake
Ecosystem Objectives (LEOs) related to nutrients:
1. Minimize the extent of hypoxic zones
associated with excessive phosphorus.
2. Maintain the levels of algae below the level
constituting a nuisance condition.
3. Maintain algal species consistent with
healthy aquatic ecosystems in the near-
shore waters of the Great Lakes.
4. Maintain cyanobacteria at levels that do not
produce concentrations of toxins that pose
a threat to human or ecosystem health in
the waters of the Great Lakes.
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Lake Erie Binational Phosphorus Reduction Strategy
5. Maintain an oligotrophic state, relative
algal biomass and algal species consistent
with healthy aquatic ecosystems, in the
open waters of Lakes Superior, Michigan,
Huron and Ontario.
6. Maintain mesotrophic conditions in the open
waters of the western and central basins
of Lake Erie, and oligotrophic conditions
in the eastern basin of Lake Erie.
Based on the LEOs, The Nutrients Annex's
Objective and Targets Task Team identified appro-
priate eutrophication indicators and quantitative
benchmarks to determine loading targets to meet
the benchmarks. For example, to meet LEO #1
(for hypoxia), the eutrophication response indicator
is dissolved oxygen concentration in the hypo Ii-
mnion of the central basin of Lake Erie and the
benchmark is to achieve (at a minimum) an aver-
age dissolved oxygen concentration of 2.0 mg/L
in August and September.
Modeling experts from the United States and
Canada applied nine different computer simulation
models2 to correlate changes in phosphorus levels
with the eutrophication indicators. These models
were built using the best available science for the
Lake Erie aquatic ecosystem. By comparing and
contrasting the results of these models, science
experts were able to arrive at recommended phos-
phorus load reduction targets that would meet the
Lake Ecosystem Objectives.
2.2 Phosphorus targets
to meet LEOs
Following extensive public consultation during
2015, Canada and the United States adopted
phosphorus reduction targets for the western and
central basins of Lake Erie on February 22, 2016
(see Table 1 below). Addressing excessive algal
growth and shoreline fouling in Lake Erie's east-
ern basin remains a priority; however, there was
insufficient science to develop a target in 2016. In
the interim, targeted research efforts are underway
to improve our scientific understanding of factors
contributing to Ciadophora growth in the eastern
basin. The viability of setting evidence-based
numeric targets for the eastern basin will be
re-evaluated in 2020.
2 For further details on the modeling effort, see: https://www.epa.gov/glwqa/annex-4-final-multi-modeling-report
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Lake Erie Binational Phosphorus Reduction Strategy 15
TABLE 1: Binational Phosphorus Load Reduction Targets
WESTERN BASIN CENTRAL BASIN
OF LAKE ERIE OF LAKE ERIE
40 percent reduction from 2008 levels in total phosphorus entering
the western and central basins of Lake Erie to achieve an annual
load of 6000 Metric Tons to the central basin. This amounts to a
reduction from Canada and the United States of 212 Metric Tons
and 3,316 Metric Tons, respectively.
40 percent reduction in spring (March - July) TP and SRP loads from
the following tributaries where localized algae is a problem3:
LAKE ECOSYSTEM
OBJECTIVE
Minimize the extent of hypoxic
zones associated with excessive
phosphorus loading, particularly
in Lake Erie's central basin.
Maintain algal species consistent
with healthy aquatic ecosystems
in the Nearshore.
Thames River - Canada
Maumee River - United States
River Raisin - United States
Portage River - United States
Toussaint Creek - United States
Leamington Tributaries - Canada
Sandusky River - United States
Huron River, Ohio - United States
Maintain cyanobacteria biomass
at levels that do not produce
concentrations of toxins
that pose a threat to human
or ecosystem health.
40 percent reduction in spring
TP and SRP loads from the
Maumee River (United States).
This equates to a target spring
load of 860 Metric Tons TP and
186 Metric Tons SRP.
Not Applicable
3 Binational and domestic efforts to reduce phosphorus will not be limited to these tributaries alone. These are a subset
of the priority tributaries for nutrient control listed in Section 3.1. Additional tributaries or watersheds may be identified in a
jurisdiction's domestic action plan as a priority for action to reduce phosphorus.
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16
Lake Erie Binational Phosphorus Reduction Strategy
FIGURE 7: Watershed map of the Lake Erie priority tributaries
for nearshore algae blooms
Ontario
London
Detroit
Cleveland
100
I Kilometers
100
I Wiles
Michigan
l l Lake Erie watershed
Indiana
0
Priority Watersheds for Nearshore Algae Blooms
I I River Raisin
I I Maumee River
WK Toussaint Creek
l I Portage River
l l Sandusky River
Huron River
I I Thames River
I I Leamington Tributaries
New York
Pennsylvania
Source: U.S. Environmental Protection Agency, 2016.
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2.3 Load Reduction Target Allocations by Country
The 2008 Water Year (October 1, 2007 - September 30, 2008) serves as the baseline for applying
the 40% reduction targets to tributaries and direct dischargers in the western and central basins.
Total phosphorus loads to the central basin in 2008 were 9,528 MT.4 To achieve the loading target of
6,000 MT to the central basin of Lake Erie, a reduction of 3,528 MT is required. Each country agreed
to reduce their load by 40% from 2008 levels. Therefore, the load reduction was allocated between
the U.S. and Canada as follows:
TABLE 2: Target Allocations by Source
SOURCE
2008 TOTAL
PHOSPHORUS LOAD
REDUCTION
REQUIRED
(Metric tons per year of total
phosphorus to the central basin)
(Metric tons per year of total
phosphorus to the central basin)
Canadian tributaries
and direct dischargers
533
212
U.S. tributaries and
direct dischargers
8,301
3,316
Atmospheric Deposition
373
-
Lake Huron input
321
-
Total
9,528
3,528
4 The 2008 baseline values can be found in Maccoux et. al 2016: https://doi.Org/10.1016/j.jglr.2016.08.005.
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Lake Erie Binational Phosphorus Reduction Strategy
Binational Priorities
for Implementation
3
Reducing phosphorus loads to the western and
central Pasins by 40% will take time and will require
the adoption of a multi-Parrier approach to prevent,
capture and treat polluted runoff. In the Maumee
River Pasin, for example, applications of multiple
watershed models have demonstrated that the forty
percent reduction goal could be achieved through
the widespread adoption of conservation practices
targeted to the areas where they are needed most.
Similar analyses in Canada support the conclusion
that phosphorus reduction targets are achievable but
will require a widespread implementation of actions.
It is recognized that there is not one solution
to addressing the problem, and that multiple
management strategies are needed to control
phosphorus from various sources and at multiple
scales. Reducing nonpoint phosphorus losses
during storm events in the non-growing season,
especially the spring, is a key priority and will Pe
critical to the success in preventing harmful and
nuisance algal Plooms in Lake Erie. Furthermore,
it is clear that current efforts to limit excess phos-
phorus loading to Lake Erie - through measures
such as implementing Pest management practices
on agricultural lands and optimizing wastewater
treatment - must continue and be enhanced.
3.1 Priority Tributaries
for Nutrient Control
Most of the total phosphorus load to the lake is
delivered from a few major triPutaries: the Detroit
River, which includes upstream triPutary inputs
from Lake Huron, the St. Clair River, as well as
the Thames River in Canada, the Maumee and
Sandusky Rivers in the U.S., and the Grand River
in Ontario. The contriPution of each river varies
from year to year depending on annual discharge,
which can Pe highly variable in response to the
intensity, amount, and timing of precipitation.
Canada and the United States identified 14 priority
triPutaries in the Lake Erie Pasin: the Detroit
River, Thames River, Leamington TriPutaries,
River Raisin, Maumee River, Toussaint Creek,
Portage River, Sandusky River, Huron River
(Ohio), Vermillion River, Cuyahoga River, Grand
River (Ohio), Cattaraugus Creek, and Grand
River (Ontario). These triPutaries are Pelieved
to contriPute most significantly to the observed
eutrophication issues in the lake's three Pasins.
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Lake Erie Binational Phosphorus Reduction Strategy
19
FIGURE 8: Average annual total phosphorus loads 2003-2013
Lake
Huron
Huron-Erie Corridor Total 2259
Atmospheric
Lake Huron
15%
Lake Ontario
East Basin Total 1060
Point Source Atmospheric
11% : I 11%
West Basin Total 3234
Point Source Atmospheric
2%
Source: Maccoux et al, 2016.
As indicated in Figure 9 below, some tributaries
contribute to both cyanobacteria growth and
seasonal hypoxia and therefore reductions in
annual TP, spring TP and SRP are required. The
loading from the Detroit River, on the other hand,
contributes to central basin hypoxia, but not to
western basin cyanobacteria, so only reductions
in the total annual TP load are required. Two
tributaries in the eastern basin - the Grand River
in Ontario and Cattaraugus Creek in New York -
were selected for further study to determine their
potential contribution to nuisance Cladophora
growth. Phosphorus reduction targets have not
yet been determined for these tributaries.
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Lake Erie Binational Phosphorus Reduction Strategy
FIGURE 9: Lake Erie Priority Tributaries for Nutrient Control
TRIBUTARY EUTROPHICATION INDICATOR
Cyanobacteria: 40%
Spring P Reduction
Central Basin Hypoxia:
40% Annual P
Reduction
Eastern Basin
Cladophora:
insufficient science to
establish P reduction
target at this time
Western
Basin
Open-water
Nearshore
Detroit River
X
Thames River
X
X
Leamington Tributaries
X
X
River Raisin
X
X
Maumee River
X
X
X
Portage River
X
X
Toussaint Creek
X
Sandusky River
X
X
Huron River (Ohio)
X
X
Vermillion River
X
Cuyahoga River
X
Grand River (Ohio)
X
Grand River (Ontario)*
X
Cattaragus Creek*
X
* While targets for Eastern Basin Cladophora have not been established to date, the Grand River, Ontario and Cattaragus Creek
have been identified as priority watersheds.
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Lake Erie Binational Phosphorus Reduction Strategy
3.2 Binational Strategies
to Support
Domestic Actions
In 2018, the United States and Canada released
domestic action plans (DAP) that outline strategies
and actions for meeting the new phosphorus load
reduction targets. The DAPs can Pe accessed here:
https://binational.net/2018/03/07/daplanphosredin
lakeerie. The plans describe the specific measures
each jurisdiction is implementing in collaboration
with its partners to achieve binational phosphorus
reduction targets for Lake Erie and, ultimately, to
curb the growth of excess algae that threaten the
ecosystem and human health.
Canada and the United States are working with
the province of Ontario and Lake Erie States,
Tribes, First Nations, and other stakeholders to
implement the domestic action plans. These plans
identify the actions required to meet the agreed
upon phosphorus load reduction targets.
Canada-Ontario: https://www.canada.ca/en/
environment-climate-change/news/2018/02/
the_governments_ofcanadaandontariorelease
actionplantoreduceharmf.html
United States: https://www.epa.gov/glwqa/
us-action-plan-lake-erie
Ohio: http://lakeerie.ohio.gov/LakeEriePlanning/
QhioDomesticActionPlan2018.aspx
Michigan: http://www.michigan.gov/
deqgreatlakes
Indiana: http://www.in.gov/isda/3432.htm
Pennsylvania: http://www.dep.pa.gov/
Business/Water/Compacts%20and%20
Commissions/Great%20Lakes%20Program/
Pages/defau It. aspx
There are currently no nutrient reduction targets for
the eastern basin of Lake Erie. However, New York
State is participating in the United States Domestic
Action Plan, and is committed to the development
of a Lake Erie watershed plan and tributary mon-
itoring program that supports the broader goals
of the Domestic Action Plan, lakewide nutrient
loading assessments and modeling efforts under
the GLWQA Nutrients Annex. The Canada-Ontario
Lake Erie Action Plan contains commitments for
the eastern basin of Lake Erie including specific
actions for the Grand River.
Each Domestic Action Plan is unique and the
categories of actions outlined below are a synthe-
sis of what can be found in the Domestic Action
Plans referenced above. Readers are encouraged
to read the Plans for specifics on the strategies
and actions that each jurisdiction is implementing.
Not all actions are a priority in every jurisdiction.
Strategy #1: Reduce Phosphorus
Loadings from Agricultural Sources
In agriculturally dominated watersheds like the
Maumee River and the Thames River basins, it is
clear that adoption of agricultural management
practices needs to be aggressive and widespread.
New approaches are needed to increase and tar-
get the adoption of conservation and stewardship
programs to maximize results. Each jurisdiction is
seeking opportunities to improve the effectiveness
of these programs and significantly increase the
current rates of adoption.
A significant portion of the phosphorus that is
contributing to the harmful and nuisance algal
blooms and hypoxia in Lake Erie originates from
surface and subsurface losses of commercial
and organic fertilizer applied to agricultural land.
Furthermore, historical applications of fertilizers are
responsible for the accumulation of phosphorus
in soils in some areas. The predominant sources
and pathways (surface or tile) will vary in the region,
depending on the land management, soil type
and other factors.
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Lake Erie Binational Phosphorus Reduction Strategy
The 4R Nutrient Stewardship Certification
program encourages agricultural retailers,
service providers and other certified profes-
sionals to implement proven best practices
through the 4Rs, which refers to using the
Right Source of Nutrients at the Right Rate
and Right Time in the Right Place.
Key actions under this strategy include:
Continue to encourage farmers to adopt
on-farm best management practices
(BMPs), emphasizing a "systems approach"
(combinations of management practices)
to comprehensively address concerns
at the farm scale.
Adopt 4R's Nutrient Stewardship Certification
or similar programs.
Avoid nutrient applications on frozen or
snow-covered ground.
Implement and enforce fertilizer and manure
application requirements where they apply.
Prevent agricultural runoff by improving soil
health and managing drainage systems to hold
back or delay delivery of runoff though the use
of saturated buffers, constructed wetlands or
other drainage water management techniques.
Reduce the impact of discharges from
greenhouses on Lake Erie.
Strategy #2: Reduce Phosphorus
Loadings from Municipal Sources
Cities, towns and villages contribute phosphorus
from wastewater treatment plant discharges
and stormwater runoff. Over the past 40 years,
significant efforts have been made to reduce
phosphorus loadings from wastewater treat-
ment facilities, however further reductions from
wastewater treatments plants are necessary.
Most wastewater treatment facilities in the basin
are currently permitted to discharge 1.0 mg/L of
total phosphorus. However, many are actually
discharging at lower rates and others present
opportunities to further reduce discharges even
in the absence of significant investments in new
treatment technologies or infrastructure. Actions
to characterize and reduce phosphorus loads from
other municipal sources will also be required.
Key actions under this strategy include:
Optimize wastewater infrastructure.
Encourage investments in green infrastructure
and low impact development.
Identify and correct failing home sewage
treatment systems.
Investigate water quality trading as a potential
tool for managing phosphorus.
Ontario, Ohio, Indiana and Michigan have
strategically reduced discharges from their
highest loading wastewater treatment facilities
using various methods described in their DAPs.
In southeast Michigan, the Great Lakes Water
Authority, largely through optimization methods
has reduced phosphorus loads from the Detroit
River by roughly 400 metric tons per year from
the baseline 2008 level. By 2020, Ontario plans
to establish a 0.5 mg/l total phosphorus legal
effluent limit in Environmental Compliance
Approvals for all wastewater treatment plants
in the Lake Erie basin over 1 million gallons
per day (3.78 million litres per day).
Strategy #3: Support
Watershed Based Planning
and Restoration Efforts
Implementation of actions to reduce phosphorus
loading to the Lake occurs at multiple scales. Local
watershed planning is the building block for these
efforts and has cumulative impacts on the Lake.
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Lake Erie Binational Phosphorus Reduction Strategy
Watershed management plans are being developed
to protect and restore water resources within
the watershed, including implementing actions
that will reduce nutrient loadings to the lake.
Jurisdictions are seeking opportunities to enhance
or refine local watershed plans to meet the phos-
phorus reduction goals for the Lake. Watershed
managers are seeking opportunities to leverage
funding, utilize non-traditional funding sources,
and consider innovative approaches to maximize
phosphorus reductions.
Using local watershed plans (where available) as the
starting point, implementation efforts are prioritized
to critical sources and areas with a high risk of
phosphorus loss. Implementation and monitoring
is coordinated within these priority areas so that
water quality improvements can be demonstrated.
Key actions under this strategy include:
Develop or refine local watershed plans to meet
the phosphorus reduction goals for the lake.
Target watershed restoration efforts to
areas most prone to phosphorus losses,
including reducing legacy phosphorus
in soils and sediments.
Restore natural hydrology and ecological
buffers to intercept nutrient runoff.
Strategy #4: Coordinate Science,
Research and Monitoring
It is important that scientists from across the basin
collaborate to assess conditions, identify science
gaps and identify the research needed to fill those
gaps. A top binational priority is to conduct the
necessary research, monitoring and modeling to
assess the effectiveness of phosphorus reduction
actions on improving algae and hypoxia conditions
in Lake Erie, and to track progress towards the
achievement of the phosphorus reduction targets
and Lake Ecosystem Objectives. Furthermore,
research and monitoring of nuisance benthic algae
('Cladophora) must be coordinated to support the
development of phosphorus reduction targets in
eastern Lake Erie.
Key actions under this strategy include:
Enhance in-lake monitoring of algae and
hypoxic conditions and conduct research on
the factors contributing to these conditions.
Improve monitoring of phosphorus loads
in tributaries and watersheds.
Invest in research and demonstration initiatives
to improve knowledge and understanding of
the effectiveness of BMPs, particularly BMPs
to control soluble reactive phosphorus.
Conduct research on factors driving toxicity
in harmful algal blooms, including the role
of nitrogen.
Apply ecosystem models to improve our ability
to predict future ecosystem conditions.
Strategy #5: Enhance
Communication and Outreach
Successful implementation of domestic action
plans requires broad support, coordination, and
collaboration among agencies, academia, local
government, Indigenous communities, private
industry, and citizens. All source and sector groups
have a role to play in contributing to our success.
Key actions under this strategy include:
Engage stakeholders on local and regional
scales to increase the understanding of water
quality condition and management challen-
ges, nearshore and beach health, and best
management practices and policies.
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Lake Erie Binational Phosphorus Reduction Strategy
Tracking and
communicating progress
towards the targets
4
The U.S. and Canada are working together to
develop an adaptive management framework for
tracking the progress towards the achievement
of targets and LEOs.
4.1 Adaptive Management
The ongoing management of phosphorus loadings
to Lake Erie and the actions required to control
them requires a roPust science program. Through
the GLWQA, the U.S. and Canada (in cooperation
with others) have committed to undertake the
necessary research, monitoring and modeling
required to estaPlish, report on and assess phos-
phorus load reduction targets and allocations
(apportioned Py country) for the management of
phosphorus and other nutrients and to improve the
understanding of relevant issues associated with
nutrients and excessive algal Plooms in the Lake.
Canada and the U.S. are committed to developing
and implementing a Pinational adaptive manage-
ment approach that will identify the science
needed to track progress in terms of achieving
the phosphorus reduction targets; reducing
harmful and nuisance algal Plooms; and reducing
the extent of hypoxia in Lake Erie. Progress will
Pe evaluated systematically and on a periodic
Pasis. Recommendations to adjust phosphorus
management strategies or targets will Pe developed
if necessary. As part of this process, emerging
issues and stressors will Pe evaluated to ensure
the targets and management actions are relevant
and effective in reducing eutrophication issues
in Lake Erie.
Tracking and reporting seasonal and annual
phosphorus loads is critical for assessing
progress. Initial efforts have Peen focused
on two immediate priorities:
1. Developing a coordinated monitoring strategy
and network for collecting compatiPle
tributary data to evaluate progress towards
meeting the phosphorus targets; and
2. Developing a system to routinely and
reliably track and report loads.
Each jurisdiction is committed to developing suites
of performance measures to track progress on
the implementation of their individual domestic
action plans. As part of the adaptive management
process, these actions will be regularly reviewed. In
addition, each domestic action plan will be revised
as necessary (at a minimum of every 5 years
starting in 2023).
-------
4.2 Reporting
Canada and the U.S. are committed to report on
progress every three years through the Progress
Report of the Parties. Each report will contain an
assessment of the Lake Ecosystem OPjectives,
progress on implementation of the domestic action
plans and the achievement in phosphorus loadings
targets and loading allocations Py country. In addi-
tion, the GLWQA Nutrients Annex SuPcommittee
will report on progress via Pinational wePinars and
the Lake Erie Lakewide Action and Management
Plan reports. In addition, individual jurisdictions
may report their progress towards achieving
targets through various means such as updates
on agency wePsites, and the ErieStat pilot pro-
gram (www.eriestat.org). The taPle Pelow presents
a summary of puPlic reporting where information
on algal Plooms, hypoxia, and phosphorus load-
ings can Pe found. For the latest information, visit
https://Pinational.net/.
TABLE 3: Lake Erie Nutrients - Summary of Public Reporting
Annual or seasonal Lake Erie Lakewide Management Annual Report
Great Lakes Executive Committee semi-annual meetings
Nutrients Annex Annual Webinar
ErieStat
Factsheets and other watershed or jurisdiction-specific reports
NOAA's Harmful Algal Bloom Forecast
Every 3 years Great Lakes Public Forum
Progress Report of the Parties
State of Great Lakes Indicators Report
Every 5 Years Domestic Action Plan Updates
Canada/US Binational Nutrient Strategy
Lake Erie Lakewide Action and Management Plan
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Lake Erie Binational Phosphorus Reduction Strategy
4.3 Expected Outcomes
In summary, the targets would achieve the following
outcomes for Lake Erie:
A 40% reduction in spring loads (TP and
SRP) from the Maumee River - This target
will significantly reduce the risk of harmful
algal blooms in the western basin by limiting
cyanobacteria biomass to "mild" levels (for
example, similar to the levels observed in
2012), in most years. Blooms may still occur,
but will be drastically reduced in spatial extent
and biomass density. Significant blooms may
still occur occasionally in extremely wet years.
A 40% reduction in spring phosphorus
loads for the nearshore priority tributaries -
This target would limit cyanobacterial growth
in nearshore areas (see map/list).
Reducing the annual total phosphorus
(TP) load to the central basin to 6,000 MT -
This target would raise the average summer
hypolimnetic dissolved oxygen concentration
to 2.0 mg/L or higher. This is the threshold for
hypoxia and should result in improvements to
the central basin bottom habitat by reducing
the release of previously sequestered phos-
phorus from anoxic bottom sediments.
In addition, the reductions needed to address
harmful algal blooms and hypoxia in the western
and central basins are expected to lower the open
lake phosphorus concentrations in the eastern basin,
helping to address Cladophora issues there.
It is difficult to predict when the expected outcomes
in the Lake will be achieved. The short residence
time (2.7 years) and the fact that algal blooms in
Lake Erie dissipated in response to phosphorus
reductions in the 1980s, indicates that the lake
should respond quickly to phosphorus reductions,
once implemented. The drought conditions of 2012,
which were associated with a small bloom, provided
a 'natural experiment', which showed that the lake
could respond very quickly to reductions in tributary
phosphorus loads. However, given the magnitude
of the problem and inherent challenges in controlling
non-point source runoff and accounting for impacts
of climate change, invasive dreissenid mussels, and
sediment-bound legacy phosphorus, there will likely
be a significant period of time before the benefits
of our implementation efforts are measurable at
a regional scale.
4.4 Conclusion
Significant actions are needed to reduce nutrient
loads from agriculture, urban, suburban, and
rural non-farm areas of the Lake Erie watershed.
All partners need to work together to seek long
term solutions for phosphorus control that are
impactful and cost effective. Partnerships with the
agricultural and municipal sectors, watershed and
non-government organizations, Indigenous com-
munities and the general public are essential to
achieving the goals of this Strategy. Governments
cannot do this alone - addressing the issue in its
myriad of forms will require sustained action, by
many partners, on both sides of the border.
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Lake Erie Binational Phosphorus Reduction Strategy | 27 |
Glossary
Adaptive management
An iterative process through which management objectives, approaches and
policies can be adjusted over time for continuous improvement based on
monitoring, performance measures, and evolving science and information.
Anoxia
An area with complete absence of oxygen.
Bioavailable
Readily assimilated by plants and algae and used for growth.
Biomass
The total mass of organisms in a given area or volume.
Best/beneficial
management practices
Proven, practical and affordable approaches to conserving or protecting soil,
water and other natural resources in urban and rural areas.
Cladophora
An attached algae species that can cause dense mats in standing water, clogging
intake pipes as well as fouling shorelines and fishing equipment. Cladophora
is the primary cause of nuisance algal blooms in Lake Erie's eastern basin.
Concentration
The mass of a substance present in a given volume of water expressed in
units such as milligrams per litre.
Cyanobacteria
Also called blue-green algae, a type of bacteria that undergoes photosynthesis
and thus can be influenced by excessive phosphorus concentrations. An
example is Microcystis. Cyanobacteria can produce toxic substances
called cyanotoxins with the potential to harm humans and other organisms.
Cyanotoxins
Toxic biological compounds produced by cyanobacteria such as Microcystis,
which produce the toxin microcystin. Cyanotoxins have potentially significant
human health consequences if ingested or through skin exposure and may
also be toxic to other organisms.
Dissolved phosphorus
See soluble reactive phosphorus.
Dreissenid mussels
A collective term used for zebra and quagga mussels, which are non-native,
invasive species in the Great Lakes basin.
Effluent
Discharge from municipal or industrial wastewater treatment plants
following treatment.
Epilimnion
The oxygen-rich upper layer of water in a stratified lake; see stratification.
Eutrophication
Excess nutrient enrichment causing nuisance and harmful algal blooms that in
turn can cause low dissolved oxygen levels and associated fish kills.
Green infrastructure
Natural and human-made elements that provide ecological and hydrological
functions and processes. Green infrastructure can include components such
as natural heritage features and systems, parklands, stormwater management
systems, street trees, urban forests, natural channels, engineered wetlands,
bioswales, permeable surfaces and green roofs.
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28 Lake Erie Binational Phosphorus Reduction Strategy
Harmful algal blooms
See cyanobacteria.
Huron-Erie corridor
The flows from Lake Huron through the St. Clair River, Lake St. Clair and the
Detroit River. Flows from the Huron-Erie corridor discharge into Lake Erie's
western basin.
Hypolimnion
The bottom layer of water in a stratified lake. In the summer, the hypolimnion
is colder than surface waters. In the winter, surface waters are frozen or
close to freezing, while the hypolimnion is somewhat warmer typically a
few degrees above freezing. The hypolimnion can experience low levels of
dissolved oxygen under certain conditions; see stratification.
Hypoxia
An area with low levels of oxygen. Late summer hypoxia the reduction of
oxygen to less than two parts per million occurs naturally in Lake Erie's
central basin due to the stratification of layers by temperature, with the
warmer layers on top.
Lakewide Action and
Established under the Canada-U.S. Great Lakes Water Quality Agreement,
Management Plan
2012, these are lake-specific binational action plans for restoring and
protecting Great Lakes ecosystems.
Load
The total mass of a substance delivered to a water body over time expressed
in units of mass per unit time, such as tonnes per year. Load is the product of
concentration (mass per unit volume) and flow rate (water volume per unit time).
Mesotrophic
Body of water with a moderate level of biological productivity and moderate
concentrations of phosphorus and/or other nutrients.
Microcystis
A genus of cyanobacteria, known to produce the toxin microcystin.
Microcystin
Toxins produced by cyanobacteria.
Non-point source Sources of pollution that are many and diffuse, in contrast to point source
pollution, which results from a single source. Non-point source pollution
generally results from land runoff, precipitation, atmospheric deposition,
drainage, seepage or hydrological modification where tracing the pollution
back to a single source is difficult.
Nuisance algal blooms Blooms of algae such as Cladophora that can cause fish kills (see eutrophication),
degrade fish and wildlife habitat, clog water intake pipes, and foul shorelines
and fishing equipment but which do not produce toxins.
Nutrient cycling The natural movement and transformation of nutrients such as phosphorus
through soil, water and air, and in different chemical forms.
Oligotrophic A body of water with a low level of biological productivity and low levels
of phosphorus and/or other nutrients.
Point source Sources of pollution that enter a water body through a pipe or similar outlet,
such as a municipal or industrial wastewater treatment plant discharge. Point
sources have usually undergone some level of treatment before discharge;
an exception is most combined sewer overflows.
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Lake Erie Binational Phosphorus Reduction Strategy | 29
Riparian zone
The area of land adjacent to tributaries and the lake where vegetation may
be influenced by flooding or elevated water tables. A healthy riparian zone
provides habitat for a variety of aquatic and terrestrial species. Its complex
vegetative structure protects against erosion and can control the runoff
of sediment, phosphorus and other pollutants, reducing impacts on water
quality under certain conditions.
Runoff
The flow of water that occurs when excess stormwater, meltwater or other
sources flow over the Earth's surface. This might occur because soil is
saturated to full capacity, rain arrives more quickly than soil can absorb it or
impervious areas send their runoff to surrounding soil that cannot absorb all
of it. Surface runoff is a major component of the water cycle and the primary
agent in soil erosion by water.
Soluble reactive
phosphorus
Phosphorus in dissolved form. The term "reactive" refers to the reaction
of phosphorus with a colour agent during the analysis of phosphate
concentrations in a laboratory.
Stormwater
Water that originates during precipitation events and snow or ice melt.
Stormwater can soak into the soil, be held on the surface and evaporate,
or run off and end up in nearby streams, rivers and other water bodies.
Total phosphorus
The combined total of dissolved and particulate phosphorus in a body of water.
Wetlands
Lands that are seasonally or permanently covered by shallow water, as well
as lands where the water table is close to or at the surface. In either case, the
presence of abundant water has caused the formation of hydric soils and has
favoured the dominance of either hydrophytic plants or water-tolerant plants.
The four major types of wetlands are swamps, marshes, bogs and fens.
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