This program, led by Environment and Climate Change Canada (ECCC), is part of a larger national program serving to describe spatial and temporal patterns in water quality on many major rivers in Canada. In Waterton, physical and chemical variables are measured at water quality sites located on the two major rivers that originate in or flow through the park, the Waterton River and the Belly River. These sites are in the headwaters of major rivers that provide ecosystem services for many downstream users (e.g. drinking water) and are upstream of major point- and non-point source pollution. National park sites represent “reference conditions” for comparison to downstream sites. These sites represent a large upstream catchment that can theoretically capture any potential impacts to water quality.