Hydrometric
stations are located on lakes, rivers, and streams of many sizes, ranging from
drainage basins as small as a few hectares to large watersheds such as the
Mackenzie Basin (1,680,000 km2). Over 2600 active water-level and streamflow
stations are currently operated under federal-provincial and
federal-territorial cost-sharing agreements. Streamflow is the volume of water
flowing past a point on a river in a unit of time (e.g., cubic metres per
second). Most stations are located in the southern part of the country; as a
result, the network is often inadequate to describe water characteristics and
trends in northern Canada. The Reference Hydrometric Basin Network (RHBN) is a
subset of stations from the national network that are used primarily for the
detection, monitoring, and assessment of climate change (ECCC, 2017). These
stations are characterized by near-pristine or stable hydrological conditions
and have been active for at least 20 years (Harvey et al., 1999) (see Figure
6.2). However, the RHBN is also unevenly distributed across Canada (with almost
no representation of the high Arctic Islands), and the length of data records
varies (Whitfield et al., 2012).
