Managing Water Supply and Flood Control in the Souris River Basin: Review of the 1989 International Agreement between the Government of Canada and the Government of the United States of America for Water Supply and Flood Control in the Souris River Basin A Report to the International Joint Commission Prepared by the International Souris River Study Board August 16, 2021 Draft Report for Public Review External Review Draft June Letter of Transmittal The International Souris River Study Board is pleased to submit its final report to the International Joint Commission, Managing Water Supply and Flood Control in the Souris River Basin. We believe the report responds in a practical and comprehensive manner to the challenge issued by the Governments of Canada and the United States to identify opportunities to improve flood control and water supply security in the international basin. We believe our report both reflects and reinforces our two countries’ long history of sound, cooperative management of the Souris River. The Study Board expresses its sincere appreciation to all the individuals who contributed to the preparation of this report. From its beginning, the Study benefitted greatly from the engagement, ideas, and enthusiasm of the many interests in the Souris River basin. First, the report is the product of a close collaborative binational effort involving more than 50 researchers in both countries. Technical teams of experts cooperated on the extensive data collection, modelling and analysis that formed the foundation of our findings and recommendations. We acknowledge and thank the members of the Study’s Public Advisory Group, who helped prepare and carry out the Study’s engagement and outreach activities so that the Study could better understand and respond to the concerns of the basin’s residents and communities. The many members of the public who participated in public meetings, workshops, webinars, and other activities improved our understanding of the challenges in the basin and how governments could better address those challenges. The Resource and Agency Advisory Group, made up of representatives of federal, state, and provincial water management and other agencies with responsibilities in the basin, worked to ensure that the Study’s analysis and recommendations are realistic and compatible with their mandates and resources. The Study Board is also grateful to Tribes, First Nations, and the Métis Nation in the basin for helping enrich our understanding of their connection to and interests in the basin’s waters and their concerns about the future of those waters. We are united in our belief that the openness and communication that were nurtured during the Study must continue as governments consider new approaches to water management in the basin. An Independent Review Group established by the International Joint Commission helped ensure the scientific integrity of the Study’s methodology and analysis through its peer review and comment. Finally, we want to thank the International Joint Commission for the opportunity to serve on the Study Board. Throughout the Study, we have listened to one another and learned from one another. We submit our report and its recommendations unanimously. Our work has only renewed our belief that an open and cooperative approach is essential to protecting the beautiful Souris River basin that our two countries share. ii External Review Draft June International Souris River Study Board Co-chair, Canada: Co-chair, United States Dr. Alain Pietroniro, P. Eng. Michael Bart University of Calgary U.S. Army Corps of Engineers (Retired July 2021) Department of Civil Engineering St. Paul, Minnesota Calgary, Alberta Former Director of the National Hydrologic Service Meteorological Service of Canada Environment and Climate Change Canada Saskatoon, Saskatchewan Members, Canada: Members, United States: Jeff Woodward Rebecca Seal-Soileau Alternate Co-chair Alternate Co-chair Environment and Climate U.S. Army Corps of Engineers Change Canada St. Paul, Minnesota Regina, Saskatchewan John Fahlman Brian Caruso Water Security Agency U.S. Fish & Wildlife Service Moose Jaw, Saskatchewan Lakewood, Colorado Mark Lee James T. Fay Manitoba Agriculture and North Dakota State Water Commission (Retired) Resource Development Bismarck, North Dakota Winnipeg, Manitoba Debbie McMechan Tammy Hanson PAG Co-chair PAG Co-chair Municipality of Two Borders Sherwood, North Dakota Pierson, Manitoba Study Co-manager, Canada: Study Co-manager, United States: Bruce Davison Gregg Wiche Environment and U.S. Geological Survey (Retired) Climate Change Canada Bismarck, North Dakota Saskatoon, Saskatchewan iii External Review Draft June Acknowledgements: The Study Team thanks all participants who contributed their valuable time and resources to this project. This study has required broad input from diverse participants in Canada and the United States: Citizens, groups, and organizations (e.g. watershed groups) Members of the public Indigenous Nations Rural and Urban communities Conservation areas Municipalities Counties Stakeholders Technical experts Numerous people and agencies All participants have provided valuable input with their vested interests, concerns, and desire to achieve effective water management in the Souris River basin. The International Souris River Study Board expresses thanks to all who provided input to the study, and expressly identifies: Public Advisory Group members and contributors Indigenous Nations, with special thanks to Marci Riel, Lisa Lone Fight, Carol Davis, Richard Aisaican, Morrissa Boerchers, Jasmine Langhan and Stewart Klyne Thank you - your contributions and input have enriched this study. iv External Review Draft June Executive Summary Managing Water Supply and Flood Control in the Souris River Basin is the final report of the International Souris River Study Board (Study Board) to the International Joint Commission (IJC) on its evaluation of water management operations under the 1989 International Agreement between the Government of Canada and the Government of the United States of America for Water Supply and Flood Control in the Souris River Basin (the 1989 Agreement). The report presents the analysis, findings, conclusions, and recommendations of the Study Board regarding opportunities to improve the 1989 Agreement and strengthen the provision of flood control and water supply benefits to interests in the international basin. The challenge The Souris River basin covers about 61,900 km2 (23,900 mi2) in the provinces of Saskatchewan and Manitoba in Canada and the state of North Dakota in the United States (Figure A). With a total population of about 157,000, the basin’s economy is relatively diversified, with a mix of agriculture, coal mining and energy production, service industries, and tourism. Long, cold winters in the basin tend to retain snowfall until the spring melt, which provides most of the Souris River’s annual flow. Much of the basin is part of the prairie pothole region, characterized by the presence of shallow potholes or kettle lakes that are remnants of the last period of continental glaciation in North America. The combination of climate and terrain contributes to highly variable flows in the basin, from season to season and from year to year. Since 1940, Canada and the United States have worked together through the IJC to jointly manage the transboundary waters of the Souris River. Today, the waters of the Souris River basin are extensively managed for flood control and water supply by dams, diversion canals and other water resource infrastructure to meet the needs of communities, agriculture, industry, recreation, and ecosystems. The current operating plan has been in place since 1989, part of the 1989 Agreement. In 2011, the Souris River basin experienced an unprecedented flood, far exceeding the scale of any other flood event in the more than 100 years for which instrumental data and records are available. Extremely wet conditions in the preceding years, combined with an above average snowmelt and heavy spring and substantial summer rainfall, resulted in a series of flooding events that significantly affected homeowners, businesses, and properties throughout the basin. Water management and control structures were severely tested as never before. The 2011 flood focused renewed attention on the existing operating plan under the 1989 Agreement. Members of the public, as well as several government flood protection and water management agencies, requested that options for additional flood protection measures be evaluated. Across the basin, there were also emerging concerns related to security of water supply, water quality and environmental protection. v External Review Draft June Figure A Souris River basin The International Souris River Study The International Souris River Study was a direct response of the Governments of Canada and the United States to the 2011 flooding event. In addition to the concerns expressed following the 2011 flooding, the 1989 Agreement requires that the Operating Plan be reviewed periodically to maximize the provision of flood control and water supply benefits that can be provided consistent with the terms of the Agreement. As a result, the International Souris River Board (ISRB), a permanent board established by the IJC responsible for oversight of transboundary water issues in the basin, including flood operations and apportionment of river flows, established the 2012 Souris River Basin Task Force to develop a Plan of Study (POS)