Irrigation water from the tidal zone of the Wairoa River, Kaipara Harbour, New Zealand 

Hume, T. M.; Male, A. J. R. 

1985 

 

 

Article in journal 

The tidal zone of the Wairoa River is 45 km long and receives drainage from a 3900 square km catchment. Waters suitable for irrigation are defined as being those with a salinity of less than 2 parts per thousand (S=2). In the Wairoa estuary the S=2 zone is a modified salt wedge of 1-3 km in length that oscillates 10-24 km up and down the river during a tidal cycle. During summer under low river inflow the high tide position of the S=2 zone may lie 24 km upstream of Dargaville past Tangowahine, while under higher winter river inflow the zone has been recorded 19 km downstream of Dargaville near Naumai. Linear regression models have been developed that allow prediction of the position of waters of salinity less than S=2 at high and low tide from river inflow. (auths) 

 

flow rates; fresh water; tidal currents; salinity; nzms262 02; nzms260q09; nzms260p07; catchments; estuaries; nzms260p08; Kaipara harbour; wairoa river; Biogeophysical; irrigation; hydrology; nzms260p09; nzms260q08; geology; coastal zone; nzms262 03