Linking Legacies to Wai

How can the research be used? Ka pēhea e whai take ai te rangahau?

• The lag time between land-use changes (largely intensification) and the increase in the load of nitrate in streams and rivers has been quantified as 4.5 years on average for 77 catchments that capture about 50% of Aotearoa’s agricultural activity.
• A key finding of this research was that without human activity such as farming, nitrate concentrations in groundwater in Aotearoa would likely be around 1.65mg/L. This has given MfE and StatsNZ justifiable reference conditions for nitrate concentrations in groundwater, and advice that the appropriate national-scale threshold ought to be 1.65 mg/L. This finding is also important for considering a nitrogen bottom-line for rivers, because most baseflow in rivers is fed by groundwater.
• This research will help set realistic timeframes to decrease nitrate concentrations in groundwater, and streams and rivers. If nitrate is not decreasing quickly enough, Councils will have evidence to take further action.