The first step in measuring the health of Canadian watersheds and the threats they face was creating an assessment protocol. To do that, WWF collaborated with Canada’s leading freshwater experts to develop a practical, science-based approach that could be applied across the country, incorporating as much relevant data from as many sources as possible.

Health assessment

The health assessment is based on four indicators — water quality, hydrology (water flow), fish and benthic invertebrates (bugs) — that represent key elements of aquatic ecosystems. We evaluate each indicator individually and assign a score ranging from very good to very poor. We calculate the overall health score by averaging the scores for the four indicators. If we don’t have enough information to confidently determine a score, we note the indicator is data deficient.

Threats assessment

The threats assessment is based on seven key threats to the health of Canada’s fresh water: pollution, climate change, invasive species, overuse of water, habitat loss, habitat fragmentation and alteration of water flows. We score each threat individually on a scale ranging from no threat to very high. Similar to the health assessment, we calculate the overall threats score by averaging the scores for the seven indicators. If we don’t have enough information to confidently determine a score, we note the indicator is data deficient.

We assess the health and threats indicators for each sub-watershed and then aggregate those results up to the level of major watersheds. We use the Water Survey of Canada boundaries for each sub-watershed and the Pearse boundaries for each major watershed. Learn more about watersheds and how they work with our Watersheds 101.

For more details, see our full methodology reports for the health and threats assessments. Or, watch the short video below to see the freshwater health assessment in action.