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“CanadiansandParliamentariansneedacomprehensive,unbiased,
science-based,reportfromanauthoritativesource,onthestateof
Canada’s freshwater quality, quantity and use. ”
Recent editions of the Canada Water Act annual report have included brief high-level overviews of the state
of water quality and quantity. Unfortunately, these summaries aggregate information to such an extreme as to be
not only uninformative, but potentially misleading.
The Canada Water Act Report to Parliament for 2022
to 2023 summarizes water quality in Canadian rivers as
fair to excellent at 83 per cent of monitored sites, before
going on to explain actual ratings of excellent or good
at only 45 per cent of monitoring sites, fair at 38 per
cent of sites, marginal at 14 per cent of sites, and poor
at two per cent of sites. It also notes that, over the past
two years, water quality remained unchanged at more
than half of the monitored sites, improved at only 10 per
cent, and deteriorated at 30 per cent.
The information is derived from the Canadian Environmental Sustainability Indicators (CESI) program
using a methodology endorsed by the Canadian Council
of Ministers of the Environment. For the period 2002 to
2020, water quality at 185 monitoring sites across Canada was assessed. At each site between five and 15 parameters were selected based on knowledge of site-specific
water quality stressors. Sampling results were compared
to water quality guidelines for the protection of aquatic
WAT E R C A N A D A . N E T
life and an index score was calculated for each site based
on: consideration of the percentage of parameters for
which water quality guidelines are not met, the percentage of samples for which guidelines are not met, and the
amount by which guidelines are not met.
The CESI water quality indicator provides a barometer of whether, on average, water quality in Canada is
improving or deteriorating. However, the higher the
level of aggregation of the CESI Indicator data across
multiple parameters and multiple sampling locations the
less useful the tool becomes for informing Canadians of
water quality challenges, their nature, their severity and
extent, their impacts, and their locations across Canada.
Water quality is determined largely by local and regional
factors, with significant variation from one drainage area
to the next, and individual parameters, be they phosphorus in Lake Winnipeg, mercury in the English and
Wabigoon rivers, or selenium in the Elk River, can pose
significant threats to human health and the environment. Both region and parameter specific challenges can
be masked by averaging of results.
Still, further analysis of detailed information provided
by CESI can yield useful insights. It shows that at more
than half of the monitored sites in Canada water quality
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