As no mainland location in the Region is further than 20 km from the coast, the catchment areas of each river are relatively small. This means that most of the rivers reach the sea before they merge with others to form large rivers. Consequently, most rivers are first and second order, meaning they are relatively small, with less than a few metres width.
The majority (63%) of rivers within the Auckland Region drain non-forested rural catchments (pastoral farming, horticulture and rural residential), followed by native forest catchments (21%), with exotic forest and urban catchments accounting for 8% each. The catchment land cover of rivers within the Auckland Region is quite different from New Zealand as a whole. These differences reflect the high population density in Auckland and the environmental pressures associated with this high population.
During the summer there is weekly monitoring at some sites. See the Auckland Council website for details.