In general, the quality of Canterbury's groundwater and surface
waters is extremely high. However, industrial, agricultural, and
urban development has had varying effects on the quality of all
the region's water bodies. Generally, water quality declines
from the mountains to the sea, reflecting the increasing
intensity of land use, changes in catchment geology, and the
accumulation of contaminants. Over the past 20 years, the
quality of some of the most degraded surface waters in
Canterbury has improved owing to a decrease in the impact of
many point-source discharges to surface waters. However, there
has been a subsequent increase in discharges to land, increasing
the risk of groundwater contamination. Less attention has been
paid to non-point source discharges, and these are now generally
having a greater effect on water quality across Canterbury than
point source discharges. The following discussion summarises the
state of water quality in this region, and describes some of the
main influencing factors. Th