It could be years before high nitrate levels drop in South Canterbury catchments, a groundwater scientist says.
According to the most recent Canterbury Water Management Strategy (CWMS) results, four out of the 10 water zones have high nitrate risk levels, including Orari-Temuka-Opihi-Pareora (OTOP) and Lower Waitaki-Coastal South Canterbury.
There is also another potential high-risk area near Ikawai, inland from Glenavy.
Environment Canterbury groundwater scientist Carl Hanson said there was a significant effort in Canterbury to manage and reduce nitrate levels in groundwater caused by more intensive farming over the past 20 years and more. Read more