A cumulative assessment of the Canadian nearshore waters of Lake Erie; integrating existing data to identify areas of high ecological value and areas subject to high stress in support of local collaborative action

Nearshore areas are a key priority in the Great Lakes Water Quality Agreement between Canada and the United States of America. This agreement sets out agreed upon goals and actions to maintain the physical, biological, and chemical integrity of the Great Lakes. The 2012 update to the agreement includes a commitment to develop and implement a nearshore framework that will identify areas that are of high ecological value and areas that may become subject to high stress. This information is then to be shared to support local scale collaboration for restoration and protection. A binational multijurisdictional task team led by Environment and Climate Change Canada developed an assessment method using data from existing monitoring programs. The team chose a Weight of Evidence approach to integrate the disparate data into a cumulative assessment because of its flexibility and transparency in communication. An expert workshop was held to evaluate available data for their relevance, strength, and reliability to formulate a decision-making framework that accounted for uncertainty and could be communicated to the public. The resulting Weight of Evidence framework consists of 12 lines of evidence evaluated to conclude the overall condition of individual reaches along the coast. These 12 lines of evidence are grouped into four categories: physical processes, contaminants in water and sediment, nuisance and harmful algae, and human use risks. This method has been applied to the Canadian portion of Lake Erie and the Huron Erie Corridor. The results showed a general gradient of poorer to higher quality from west to east along the shore and the primary issues were shoreline alteration and impacts from Harmful Algae Blooms. The Lake Erie results have been shared with local communities and has triggered the formation of a community group consisting of government, landowners, and ENGOS in a poorer quality area who are taking action to improve the state of the local nearshore waters.