Summary
NIWA (and predecessor organisations) has a long history of undertaking technical work related to
understanding the ecological status and water quality of the Manukau Harbour, as well as
hydrodynamics of the harbour. Much of the latter work has been associated with specific activities:
• assessment of environmental effects associated with the discharge of treated wastewater.
• prediction of the fate and potential environmental or human health effects of various
contaminants.
• understanding potential effects arising from infrastructure projects (e.g., the construction of
bridges), or the effects of storm surges on infrastructure.
• potential effects related to discharges of stormwater (particularly the fate and potential
effects of various contaminants).
The discharge of well-treated wastewater from Mangere wastewater treatment plant is the single
largest freshwater inflow to the Manukau Harbour. It is also a point source of nitrogen and
phosphorus. Much of the historical hydrodynamic modelling of the Manukau Harbour has been
undertaken to better understand the fate and potential effects of well-treated wastewater.
Work currently being undertaken by NIWA for Watercare Services Limited is aimed at extending our
knowledge of the fate and effects of contaminant inputs from all inflows to the harbour.
The following reports have some connection to hydrodynamic modelling in Manukau Harbour. A few
of these represent summaries of essential field studies (data collection) that may subsequently be
used for model development purposes. Recent examples include Pinkerton (2017), and MacDonald
and Broekhuizen (2018).
Hydrodynamic modelling reports
Carter, L., Mitchell, J.S. (1991) Auckland Area Sewerage Study. Bathymetric investigations Manukau
Harbour. Report on first stage investigations. NZOI, DMF, Wellington: 9 p., 1 app (in 3 sections).
Green, M. (2008a) Southeastern Manukau Harbour/Pahurehure Inlet contaminant study:
implementation and calibration of the USC-3 Model. NIWA Client Report. Report no. HAM2008-140,
122 pp.
http://www.aucklandcity.govt.nz/council/documents/technicalpublications/TR2008057.pdf
Green, M. (2008b) Southeastern Manukau Harbour/Pahurehure Inlet contaminant study: predictions
of sediment, zinc and copper accumulation under Future Development Scenario 1. NIWA Client
Report. Report no. HAM2008-141, 117 pp.
https://www.aucklandcouncil.govt.nz/plans-projects-policies-reports-bylaws/our-plans-
strategies/unitary-plan/history-unitary-plan/documentssection32reportproposedaup/appendix-3-2-
13.pdf
Green, M. (2008c) Southeastern Manukau Harbour/Pahurehure Inlet contaminant study: predictions
of sediment, zinc and copper under Future Development Scenarios 2, 3 and 4 NIWA Client Report.
Report no. HAM2008-142, 121 pp.
https://www.aucklandcouncil.govt.nz/plans-projects-policies-reports-bylaws/our-plans-
strategies/unitary-plan/history-unitary-plan/documentssection32reportproposedaup/appendix-3-2-
9.pdf
Greig, M.J. (1991) Auckland Area Sewerage Study. Hydrological investigations, Manukau Harbour.
Monthly progress report no. 2, June 1991. NZOI, DMF, Wellington: 2 p. [+ 26 p.].
Greig, M.J., Chiswell, S.M. (1991) Auckland Area Sewerage Study. Hydrological investigations,
Manukau Harbour. Report on first stage investigations Papakura Channel. NZOI, DMF, Wellington: 19
p., 14 app.
Greig, M.J., Mitchell, J.S. (1991) Auckland Area Sewerage Study. Hydrological and bathymetric
investigations. Manukau Harbour. Monthly progress report no. 1. May 1991. NZOI, DMF, Wellington:
5 p.
Greig, M.J., Stanton, B.R. (1992) Auckland Area Sewerage Study. Hydrological investigations Manukau
Harbour. Reports on currents in Purakau Channel, Manukau Harbour. NZOI, NIWA, Wellington: 5 p., 8
figs.
MacDonald, I., Broekhuizen, N. (2018) Moored instrument measurements of hydrodynamic and
water‐quality properties in the northern Manukau harbour: September and October 2017. NIWA
Client Report. Report no. 2018300HN, 66 pp.
Oldman, J.W., Bryan, K., Black, K.P. (1999) Manukau STP Ponds 1 and 2 Breach modelling. NIWA,
Hamilton: 124 p.
Pinkerton, M. (2017) Satellite remote sensing of water quality and temperature in Manukau Harbour.
NIWA Client Report. Report no. 2017092WN, 76 pp.
Pritchard, M., Gorman, R., Lewis, M. (2008a) SE Manukau harbour and Pahurehure inlet contaminant
study: hydrodynamic, wave and sediment-transport model implementation and calibration. NIWA
Client Report. Report no. HAM2008-138, 65 pp.
http://www.aucklandcity.govt.nz/council/documents/technicalpublications/TR2008056.pdf
Pritchard, M., Hancock, N., Lewis, M. (2008b) Manukau and Pahurehure Inlet contaminant study:
harbour hydrodynamics and sediment transport fieldwork. NIWA Client Report. Report no.
HAM2008-133, 29 pp.
http://www.aucklandcity.govt.nz/council/documents/technicalpublications/TR2008055.pdf
Reeve, G., Broekhuizen, N. (2019) Manukau Harbour hydrodynamic model - calibration and validation.
NIWA Client Report. Report no. 2019124HN, 52 pp.
Senior, A.K., Oldman, J.W. (1999) Manukau STP Ponds 3 and 4 breach modelling. Manukau
Wastewater Services Limited, Hamilton: 121.
Stephens, S., Wadhwa, S., Bell, R. (2016) Coastal hazard and sea-level rise inundation exposure for
Onehunga, Mangere and Manukau. NIWA Client Report. Report no. HAM2016-066, 29 pp.
