Canadian Environmental Sustainability Indicators Nutrients in Lake Winnipeg Suggested citation for this document: Environment and Climate Change Canada (2018) Canadian Environmental Sustainability Indicators: Nutrients in Lake Winnipeg. Consulted on Month day, year. Available at: www.canada.ca/en/environment-climate-change/services/environmental- indicators/nutrients-in-lake-winnipeg.html. Cat. No.: En4-144/70-2018E-PDF ISBN: 978-0-660-27807-0 Unless otherwise specified, you may not reproduce materials in this publication, in whole or in part, for the purposes of commercial redistribution without prior written permission from Environment and Climate Change Canada's copyright administrator. To obtain permission to reproduce Government of Canada materials for commercial purposes, apply for Crown Copyright Clearance by contacting: Environment and Climate Change Canada Public Inquiries Centre 12th floor, Fontaine Building 200 Sacré-Coeur boul. Gatineau, QC K1A 0H3 Telephone: 1-800-668-6767 (in Canada only) or 819-938-3860 Fax: 819-938-3318 Email: [email protected] Photos: © Thinkstockphotos.ca; © Environment and Climate Change Canada © Her Majesty the Queen in Right of Canada, represented by the Minister of Environment and Climate Change, 2018 Aussi disponible en français Nutrients in Lake Winnipeg Page 2 of 28 Canadian Environmental Sustainability Indicators Nutrients in Lake Winnipeg September 2018 Table of Contents Nutrients in Lake Winnipeg ................................................................................................................. 5 Phosphorus and nitrogen levels in Lake Winnipeg ............................................................................ 5 Key results ...................................................................................................................................... 5 Phosphorus levels by water quality monitoring site ........................................................................... 7 Key results ...................................................................................................................................... 7 Nitrogen levels by water quality monitoring site ................................................................................. 8 Key results ...................................................................................................................................... 8 Reducing phosphorus loads to Lake Winnipeg .................................................................................. 9 Key results ...................................................................................................................................... 9 About the indicators .......................................................................................................................... 10 What the indicators measure ........................................................................................................ 10 Why these indicators are important .............................................................................................. 10 Related indicators ......................................................................................................................... 10 Data sources and methods............................................................................................................... 11 Data sources ................................................................................................................................ 11 Methods ........................................................................................................................................ 12 Recent changes ............................................................................................................................ 14 Caveats and limitations ................................................................................................................ 14 Resources......................................................................................................................................... 15 References ................................................................................................................................... 15 Canadian Environmental Sustainability Indicators Page 3 of 28 Related information ...................................................................................................................... 15 Annex ................................................................................................................................................... 16 Annex A. Data tables for the figures presented in this document .................................................... 16 List of Figures Figure 1. Status of phosphorus and nitrogen levels in Lake Winnipeg, 2016, and its 3 largest tributary rivers, Canada, 2014 to 2016 .............................................................................................. 5 Figure 2. Annual total phosphorus concentrations in Lake Winnipeg and its 3 largest tributary rivers, Canada, 1999 to 2016 ............................................................................................................ 7 Figure 3. Annual total nitrogen concentrations in Lake Winnipeg and its 3 largest tributary rivers, Canada, 1999 to 2016 ....................................................................................................................... 8 Figure 4. Estimated cumulative reduction in the amount of phosphorus reaching Lake Winnipeg because of completed stewardship projects, Canada, April 2010 to March 2017 ............................ 9 List of Tables Table 1. Tributary water quality monitoring sites ............................................................................. 11 Table A.1. Data for Figure 1. Status of phosphorus and nitrogen levels in Lake Winnipeg, Canada, 2016 ................................................................................................................................................. 16 Table A.2. Data for Figure 1. Status of phosphorus and nitrogen levels in Lake Winnipeg's 3 largest tributary rivers, Canada, 2014 to 2016 ............................................................................. 16 Table A.3. Data for Figure 2. Seasonally-weighted annual average total phosphorus levels in the north basin, Lake Winnipeg, Canada, 1999 to 2016 ....................................................................... 17 Table A.4. Data for Figure 2. Seasonally-weighted annual average total phosphorus levels in the south basin and narrows, Lake Winnipeg, Canada, 1999 to 2016 .................................................. 18 Table A.5. Data for Figure 2. Annual total phosphorus concentration data for the Saskatchewan River, Canada, 1999 to 2016 ........................................................................................................... 19 Table A.6. Data for Figure 2. Annual total phosphorus concentration data for the Red River, Canada, 1999 to 2016 ..................................................................................................................... 20 Table A.7. Data for Figure 2. Annual total phosphorus concentration data for the Winnipeg River, Canada, 1999 to 2016 ..................................................................................................................... 21 Table A.8. Data for Figure 3. Seasonally-weighted annual average total nitrogen levels in the north basin, Lake Winnipeg, Canada, 1999 to 2016................................................................................. 22 Table A.9. Data for Figure 3. Seasonally-weighted annual average total nitrogen levels in the south basin and narrows, Lake Winnipeg, Canada, 1999 to 2016 ............................................................ 23 Table A.10. Data for Figure 3. Annual total nitrogen concentration data for the Saskatchewan River, Canada, 1999 to 2016 ........................................................................................................... 24 Table A.11. Data for Figure 3. Annual total nitrogen concentration data for the Red River, Canada, 1999 to 2016 .................................................................................................................................... 25 Table A.12. Data for Figure 3. Annual total nitrogen concentration data for the Winnipeg River, Canada, 1999 to 2016 ..................................................................................................................... 26 Table A.13. Data for Figure 4. Estimated cumulative reduction in the amount of phosphorus reaching Lake Winnipeg because of completed stewardship projects, Canada, April 2010 to March 2017 ................................................................................................................................................. 27 Nutrients in Lake Winnipeg Page 4 of 28 Nutrients in Lake Winnipeg Phosphorus and nitrogen are essential plant nutrients. When phosphorus or nitrogen levels are too high or too low, they can have harmful impacts on the food web of a lake or river. They are a measure of the health of Lake Winnipeg and its surrounding watershed. These indicators provide the status of phosphorus and nitrogen levels in Lake Winnipeg and 3 of its tributary rivers. Phosphorus and nitrogen levels in Lake Winnipeg Key results In Lake Winnipeg, the highest levels of phosphorus and nitrogen in 2016 are found in the south basin near the inflow from the Red River. Levels decline as the water