Raumanga Stream is one of major tributaries of the Hātea River estuary draining the suburbs of Maunu, Raumanga, and Horahora located in the western part of the Whangārei City. The last five years (2015-2019) of monthly SoE water quality monitoring shows higher concentration of dissolved inorganic nitrogen (DIN) and faecal pathogen (Escherichia coli or E. coli) in the Raumanga Stream compared to other main catchments contributing to the Hātea River estuary. A one-year water quality investigation programme was established by Northland Regional Council to ascertain the source of elevated nutrient concentration and microbial contamination observed in the Raumanga Stream.