Water quality and ecosystem health data used to conduct a cumulative effects assessment of Lake Ontario, Niagara River and St. Lawrence River nearshore waters in support of the Great Lakes Water Quality Agreement are included in this dataset. Data related to nearshore stressors is integrated into an overall assessment in a three-phased approach: 1) classification of the nearshore into Regional Units using physical processes and lake characteristics; 2) overall assessment of the state (cumulative stress) of each Regional Unit; and 3) integrate additional information related to nearshore areas of high ecological value.
Assessment data is presented within a 30 metre depth zone along the coast. For purposes of determining stress on nearshore waters it is necessary to consider the zones of influence and zones of impact. Measures used to assess the nearshore waters of Lake Ontario are broken into four categories: 1) Coastal Processes (Shoreline Hardening, Littoral Barriers, Tributary Connectivity); 2) Contaminants in Water & Sediment (Water Quality, Sediment Quality, Benthic Community); 3) Nuisance & Harmful Algae (Cyanobacteria, Cladophora); and 4) Human Use (Beach Postings, Fish Consumption, Treated Drinking Water).