The Ottawa drainage region extends across 146,353 km2 of Ontario and Quebec and includes Ottawa–Gatineau. In 2011, the majority (92.2%) of the total area was natural and semi-natural land, followed by arable land (4.6%), built-up area (2.4%) and natural land for pasture (0.8%).
The population was 1,957,937 in 2011—6% of Canada’s total—with a population density of 14.9 persons/km2. Population was up 65% compared to 1,183,662 in 1971.
Surface freshwater intake from drinking water plants, manufacturing, mining, thermal-electric production and irrigation was 364.9 million m3 in 2013.
The average annual water yield was 64.3 km3 over the period 1971 to 2013. The water yield per unit area was 0.44 m3/m2, compared to 0.35 m3/m2 at the Canada level. Monthly water flows peak in April. Data on trends over time are not available. The region had the fourth highest evapotranspiration at 0.47 m3/m2.
Sources of nitrogen and phosphorus residuals in the environment include fertilizer application and livestock and poultry production. On average residual soil nitrogen on agricultural land was 33.2 kg/ha in 2011 compared to 23.2 kg/ha at the Canada level.
