The Punakitere River, originating from a wetland area southwest of Kaikohe, is a major tributary into the Waima River (which flows into the Hokianga Harbour). The catchment is predominantly agricultural land use with an underlying geology of soft sediments.
The 2005-2006 results for Punakitere River are summarised in the table below including the median, range and percentage of sampling occasions that comply with relevant guidelines for the 12 sampling occasions. Medians shown in red are outside the recommended guidelines.
|Parameter||Median||Range||% comply with guideline|
|Temperature (deg. cel.)||15.7||10.7 - 21.3|
|Dissolved oxygen (mg/L)||9.8||8.2 - 12.7||100|
|Dissolved oxygen (% Sat.)||96.6||90.5 - 114.3||33|
|Conductivity (mSm)||12.7||11.3 - 15|
|Water clarity (m)||1.30||0.22 - 2.32||73|
|Turbidity (NTU)||5.4||1.3 - 24||50|
|E. coli (n/100mL)||394||162 - 1414||0|
|Dissolved reactive phosphorus (mg/L)||0.033||0.01 - 0.079||8|
|Total phosphorus (mg/L)||0.067||0.025 - 0.134||8|
|Ammoniacal nitrogen (mg/L)||0.010||0.005 - 0.06||83|
|Total nitrogen (mg/L)||0.862||0.301 - 1.24||33|
|pH||7.6||6.8 - 7.9||83|
Similarly to the last two year's results, the 2005-2006 results indicate that Punakitere River suffers from significant nutrient overloading and bacterial contamination, with the median E. coli, dissolved reactive phosphorus, total phosphorus and total nitrogen results exceed their respective guidelines. Run-off is the likely source of nutrient and bacterial contamination in Punakitere River.
There is only just five years data to be able to carry out trend analysis on the results from Punakitere River, so caution should be taken as these trends could possibly change or more could become apparent next year when the trend analysis is repeated. However at this stage the only two significant trends are decreasing nitrite/nitrate nitrogen and increasing pH, both of which are seen as an improvement.