Waikato Regional Council estimates nitrogen leaching and runoff in a representative sample of catchments across the region. This helps us to identify sensitive water bodies at risk of increased nitrogen levels.
This indicator is based on the amounts (loads) of nitrogen getting into our water, either through surface runoff or subsurface runoff (leaching). We calculated it for a wide range of catchments as the area-weighted averages of estimated nitrogen inputs to water.
Our research shows that nitrogen loading into rivers from developed land (non-point sources) in this region is closely related to the average stocking rate of dairy cows (view graph). This is because nitrogen in animal urine moves very easily through the soil and groundwater. This makes it possible to use an area’s dairy cow stocking rate to estimate the nitrogen loading into waterways. The information on nitrogen loading in this indicator has been estimated from each area’s dairy cow stocking rate.
There are no plans to update this indicator at present.
Water Quality Scientist - Science and Strategy Directorate