DRP mapsep2014.jpg

Locations of all 77 sites in the National River Water Quality Monitoring Network. Relative concentration of dissolved reactive phosphorus (DRP, average of monthly data, 2005 to 2011) is shown by the size of the circles. Red circles in the South Island indicate sites where didymo blooms are present, and all have average DRP < ~2 ppb. Sites marked with blue circles have no didymo blooms. Visible didymo has been observed occasionally at sites with red and blue circles. Highest mean DRP (Tarawera) is 67.7 ppb, and lowest (Monowai) is 0.6 ppb.