The Development of a Stressor-Response Model for the Red River of the North

The International Red River Board (IRRB), a board of the International Joint Commission (IJC), identified excess nutrients as one of the greatest issues in the Red River of the North because of its impact on the ecological conditions in the Red River itself and its significant contribution to hyper-eutrophic conditions in downstream Lake Winnipeg. Excessive nutrient contributions to the lake have led to excessive algal blooms that impact drinking water, recreation, and commercial fisheries through significant
accumulations of algal biomass—the Red River has been identified as the most significant contribution of the nutrients. This excessive algal buildup disrupts recreation and fisheries through its physical presence but also by indirectly attributing to dissolved oxygen depletion at night when photosynthesis shuts down and bacterial decomposition of the dead algae utilize large amounts of oxygen. To initiate determining solutions to these issues, the IRRB developed a proposed approach for a basin-wide, nutrient management strategy for the international Red River Watershed. One component of this approach involves developing nitrogen and phosphorus concentration targets within the mainstem Red River as a first step in restoring the ecology of the Red River and reducing nutrient contributions to Lake Winnipeg.

To determine an approach for establishing nutrient targets, the IRRB contracted with RESPEC to conduct a literature review and provide recommendations on the most appropriate method for developing nitrogen and phosphorus targets in the Red River [Plevan and Blackburn, 2013]1. Based on these findings, the IRRB determined that a collaborative project to determine a biological stressor response in the Red River to nutrients was necessary. The subsequent project was developed by a team that consisted of agency professionals from Manitoba, Minnesota, North Dakota, and RESPEC. The project results are described in this report and demonstrates the development of a stressor-response model that includes the identification of biologically based nutrient targets in the Red River.