The longest river in New Zealand is the Waikato River
(425km).
Other notable rivers include the Clutha River, which has the
largest volume. The Rakaia River is crossed by the longest bridge
(1.75km). The Whanganui River is popular for kayak tours. The
Shotover River near Queenstown is home to the famous Shotover
Jetboat rides.
The Manawatu River is renowned for being one of the most
polluted rivers in the western world. Industrial waste, treated
sewage, and, most particularly, nutrient land runoff from dairy
farms are the causes.