Reductions in phosphorus loads to Lake Winnipeg
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Lake Winnipeg is the sixth largest freshwater lake in Canada, with its drainage basin stretching over 4 provinces and 4 U.S. states. The land in the basin is mainly used for agriculture and is home to nearly 7 million people.
The deterioration of water quality in Lake Winnipeg is mainly caused by nutrients and other contaminants from various sources throughout the basin. The increased concentration in nutrients and algal blooms since the mid-1990s has been partially due to an increase in precipitations, runoffs, floods, and river flows.Footnote 1
Phosphorus is an essential plant nutrient. However, when phosphorus levels are too high, or too low, they can have harmful impacts on a lake's water quality and food web as observed in Lake Winnipeg. In the absence of human development, natural background levels of phosphorus are relatively low. High phosphorous levels in Lake Winnipeg may result from human-related factors such as agricultural runoff and urban runoff. Reducing the amount of phosphorus that enters Lake Winnipeg helps to improve water quality and the ecosystem health of the lake.
Environment and Climate Change Canada’s support and funding for the efforts to reduce nutrients, through the Lake Winnipeg Basin Program, will help Manitoba achieve its long-term goal of reducing phosphorus concentrations in the lake by 50% to pre-1990 levels. This indicator shows the extent to which the projects completed since 2010 have reduced the amount of phosphorus reaching Lake Winnipeg.
Key results
Key results
- Projects completed between 2010 and 2023 have prevented an estimated 390 445 kilograms of phosphorus from reaching Lake Winnipeg
Drainage basin of Lake Winnipeg
Source: Environment and Climate Change Canada (2020) State of Lake Winnipeg, second edition.
Estimated cumulative reduction in the amount of phosphorus reaching Lake Winnipeg as a result of projects implemented through Environment and Climate Change Canada’s Lake Winnipeg basin programming, April 2010 to March 2023
Data table for the long description
| Year | Estimated phosphorus removal (kilograms of phosphorus per year) |
Estimated one-time phosphorus removal (kilograms of phosphorus) |
Total estimated phosphorus removal over all years (kilograms of phosphorus) |
|---|---|---|---|
| 2011 | 4 906 | n/a | 4 906 |
| 2012 | 1 586 | n/a | 11 398 |
| 2013 | 0[A] | n/a | 17 890 |
| 2014 | 122 | n/a | 24 504 |
| 2015 | 8 194 | n/a | 39 312 |
| 2016 | 7 403 | 21 345 | 82 869 |
| 2017 | 7 504 | n/a | 112 583 |
| 2018 | 0[A] | n/a | 142 298 |
| 2019 | 9 | n/a | 172 022 |
| 2020 | 1 609[B] |
n/a | 203 355[B] |
| 2021 | 14 881 | n/a | 249 569[B] |
| 2022 | 23 164 | n/a | 318 947 |
| 2023 | 2 120 | n/a | 390 445 |
Note: n/a = not applicable. [A] No new phosphorus reduction projects were funded that year. [B] The value has been updated as a result of a correction in the reported value from a completed project.
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How this indicator was calculated
Note: The estimated reduction in phosphorus load is based on the results of Environment and Climate Change Canada’s Lake Winnipeg basin programming funded projects completed between April 2010 and March 2023. Estimated phosphorus reductions for each project are summed yearly to calculate the cumulative total. One specific project, the bioremediation of a retired municipal wastewater lagoon, prevented 21 345 kilograms of phosphorus from reaching Lake Winnipeg in 2016 as a one-time phosphorous reduction. One-time phosphorous reductions do not contribute to the cumulative total. Year refers to fiscal year, which runs from April 1 to March 31. The year 2023 therefore refers to April 1, 2022 to March 31, 2023.
Source: Environment and Climate Change Canada (2023) Lake Winnipeg Basin Program.
The amount of phosphorus reaching Lake Winnipeg is being reduced by projects which have received funding for activities such as:
- building retention ponds that intercept water flow across the landscape and capture nutrients
- stabilizing river banks and lake shorelines
- restoring wetlands
- supporting innovative technologies related to small scale wastewater management systems
- implementing management practices that prevent livestock from entering lakes and rivers
Environment and Climate Change Canada, the Manitoba government and other partners are engaging people in nutrient reducing activities and supporting innovative nutrient reduction demonstration projects and research. Environment and Climate Change Canada's support for these types of efforts through the Lake Winnipeg Basin Program will help Manitoba achieve its long-term goal of reducing phosphorus concentrations in the lake by 50% to pre-1990 levels.
About the indicator
About the indicator
What the indicator measures
The reductions in phosphorus loads to Lake Winnipeg indicator shows the estimated extent to which projects funded by the Lake Winnipeg Basin Stewardship Fund (from April 2008Footnote 2 to March 2017) and the Lake Winnipeg Basin Program (since March 2017) have reduced the amount of phosphorus reaching the lake from its watershed.
Why the indicator is important
Clean fresh water is an essential resource as it supports healthy aquatic ecosystems. We use it for manufacturing, energy production, irrigation, swimming, boating, fishing, traditional cultural practices, and for domestic use such as drinking and washing. Degraded water quality damages the health of freshwater ecosystems and can disrupt economic activities, such as fisheries, tourism and agriculture, and can negatively impact Indigenous traditional uses.
When phosphorus levels in water become too high, aquatic plant growth can become excessive and harmful to the ecosystem health of the lake. The decay of excess plant material can reduce the amount of oxygen available for fish and other aquatic animals. High nutrient levels can also lead to harmful algal blooms, which can be toxic to animals that use the water and adversely affect human health. It is important to reduce human-related causes of excess nutrients and minimize phosphorus input into the lake. Conversely, too little phosphorus can result in not enough plant or algal growth to support a lake's food web, which could reduce fish populations and impact local fisheries. Reducing the amount of nutrients, such as phosphorus, reaching Lake Winnipeg will help improve the health of the lake.
Related initiatives
This indicator contributes to the Sustainable Development Goals of the 2030 Agenda for Sustainable Development. It is linked to Goal 6, Clean Water and Sanitation and Target 6.3, "By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally."
Related indicators
The Phosphorus levels in the offshore waters of the Great Lakes, the Nutrients in the St. Lawrence River and the Nutrients in Lake Winnipeg indicators report the status of total phosphorus and total nitrogen levels in these 3 ecosystems.
The Phosphorus loading to Lake Erie indicators report on the total phosphorus loadings flowing directly into Lake Erie or from its tributary rivers.
The Water quality in Canadian rivers indicators provide a measure of the ability of river water across Canada to support plants and animals.
The Household use of chemical pesticides and fertilizers indicator reports on how many people in Canada use pesticides and fertilizers – the latter of which can be a source of nutrients entering the water supply – on their lawns and gardens.
Data sources and methods
Data sources and methods
Data sources
The amount of phosphorus diverted from Lake Winnipeg through Environment and Climate Change Canada's Lake Winnipeg basin programming was either provided in final project reports submitted by funding recipients or estimated by Environment and Climate Change Canada.
More information
The estimated phosphorus load reductions are calculated using the results of Environment and Climate Change Canada funded projects completed in the Lake Winnipeg watershed between April 2010 and March 2023. The indicator includes data for all projects completed by March 31, 2023.
From 2008 to 2023, Environment and Climate Change Canada's Lake Winnipeg basin programming funded 178 projects. Of the projects funded, 48% are having a direct impact on phosphorus loading and 52% are having an indirect impact. The indicator reports on projects resulting in direct reductions of phosphorus loadings to Lake Winnipeg.
Projects approved by Environment and Climate Change Canada (ECCC) are funded through Contribution Agreements that are signed with individual funding recipients. For some projects, where a Contribution Agreement is already in place with a funding recipient, ECCC may choose to amend that agreement to include additional project activities and funding instead of signing a new one. In these cases, the project is not counted as a new project and therefore not reflected in the total number of projects that are approved annually by ECCC. However, the phosphorus reductions realized through additional activities carried out via amended agreements are included in the calculations for this indicator.
Methods
Load reductions were estimated for each project using project-specific equations that were either derived independently based on project data or from the Lake Simcoe Clean-Up Fund: Phosphorus Reduction Calculation Report.Footnote 3 The Lake Simcoe report is applicable to projects in the Lake Winnipeg basin because it uses generic land use models collected from scientific literature. The results for each year were added to estimate the total loading reduction.
More information
In general, the concentration of phosphorus reaching a watercourse is determined by the form and chemical nature of the phosphorus compounds and the degree of contact with the soil, soil pH, soil texture, soil type and aerobic conditions. Projects to reduce phosphorus inputs from agriculture include practices such as limiting livestock access to streams through fencing and installing alternate watering sources. Other projects include those that protect or stabilize stream banks or lake shores by installing erosion-control structures and planting trees and shrubs.
Once a project has been initiated, its impact on the removal of phosphorus in water running off the landscape is accounted for on a yearly basis. Loading reductions achieved each year over the life of the project are added to projects completed in 2010.
The phosphorus reduction results are calculated estimates, and the figures for each project type were summed to produce the final number.
Caveats and limitations
The indicator assumes that each phosphorus reduction project completed through Environment and Climate Change Canada’s Lake Winnipeg basin programming has resulted in a permanent annual reduction in phosphorus loads to Lake Winnipeg.
The indicator does not compare results to annual phosphorus load data for the lake or rivers or the overall land use and activity changes in the basin that might affect phosphorus loading.
The indicator relies on the most appropriate equations to predict phosphorus loading reductions from the implementation of the projects. Despite the rigour behind them, uncertainty exists when using these equations.
Resources
Resources
References
Sealock L (2011) Lake Simcoe Clean-Up Fund: Phosphorus Reduction Calculation Report. Great Lakes Management and Reporting Section, Environment Canada.
Related information
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