The Columbia drainage region extends across 87,323 km2 in south-eastern British Columbia. Natural and semi-natural area accounted for 97.7% of the total area in 2011, with small amounts of arable land (0.5%), natural land for pasture (1.0%) and built-up area (0.8%).
The population was 160,896 in 2011, with a population density of 1.9 persons/km2.
Surface freshwater intake from manufacturing, drinking water plants, irrigation and mining was 190.7 million m3 in 2013.
The average annual water yield was 67.9 km3 over the period 1971 to 2013. The water yield per unit area was 0.78 m3/m2, more than double the 0.35 m3/m2 at the Canada level. Monthly water flows peak in June.