Water Quality and Nutrient Loading

The briefing assesses water quality and nutrient loading in the lower Winnipeg River basin (LWRB), identifying significant exceedances of total phosphorus and certain metals, particularly at the Pine Falls Forebay. It highlights that the Winnipeg River is a major nutrient contributor to Lake Winnipeg, with nutrient exports increasing downstream. The document also notes that climate projections suggest increased precipitation and runoff, which may further impact nutrient loading.

• The lower Winnipeg River is well oxygenated across all seasons, with a mean dissolved oxygen concentration of approximately 10 mg/L, which exceeds the Canadian Council of Ministers of the Environment guidelines of 5.0 to 9.5 mg/L for warm- to cold-water biota.
• Total phosphorus (TP) concentrations frequently exceed guidelines in the LWRB, with the highest percentage of exceedances occurring at the Pointe du Bois Forebay (85.3%) and Pine Falls Forebay (81%).
• Aluminum, iron, and copper levels have exceeded protection of aquatic life (PAL) guidelines, with Pine Falls Forebay showing the most significant issues: 100% of samples exceeded aluminum guidelines and 58% exceeded copper guidelines.
• The Winnipeg River is the second largest absolute contributor of nutrients to Lake Winnipeg, accounting for approximately 25% of total nitrogen (TN) and 15% of total phosphorus (TP) loads.
• Nutrient exports increase downstream between Pointe du Bois and Pine Falls, with the reach between these two sites producing nutrient exports nearly three to four times higher than at each individual site.
• Water volume is a primary driver of nutrient export from the Winnipeg River, with 97% of total nitrogen and 79% of total phosphorus loading variation attributed to river flows.
• Climate projections for the 2050s suggest a 6.9% increase in mean annual precipitation and a 3.3% increase in runoff into the Winnipeg River basin, which could impact downstream nutrient loading.

APA

International Institute for Sustainable Development (2021). Water Quality and Nutrient Loading. https://www.iisd.org/system/files/2021-06/winnipeg-river-basin-sheet-4-water-quality-nutrient-loading.pdf

Chicago

International Institute for Sustainable Development. Water Quality and Nutrient Loading. 2021. https://www.iisd.org/system/files/2021-06/winnipeg-river-basin-sheet-4-water-quality-nutrient-loading.pdf.

Wikipedia

{{cite report |author=International Institute for Sustainable Development |title=Water Quality and Nutrient Loading |date=May 2021 |url=https://www.iisd.org/system/files/2021-06/winnipeg-river-basin-sheet-4-water-quality-nutrient-loading.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{internationalinstituteforsustainabledevelopment2021water, author = {{International Institute for Sustainable Development}}, title = {{Water Quality and Nutrient Loading}}, institution = {International Institute for Sustainable Development}, year = {2021}, month = may, url = {https://www.iisd.org/system/files/2021-06/winnipeg-river-basin-sheet-4-water-quality-nutrient-loading.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }