IC39_NZ

Terrestrial sediment fluxes to coastal environments can adversely affect ecosystem functioning and reduce navigability within ports and estuaries. In order to assess the ecosystem state, the flow circulations and sedimentary pathways within estuaries need to be understood. Our research focuses on the physical processes that control the movement and deposition of estuarine sediments within the barrier-enclosed estuarine lagoon of Tauranga Harbour, New Zealand. By combining field data and a numerical modelling study, we explore these sediment pathways and the connectivity in the estuary as a whole, as well as the relationship between hydrodynamics, intertidal morphology and external forcings.

In November 2015, a month-long extensive field campaign was conducted to obtain hydrodynamic data and suspended sediment concentrations at multiple locations within Tauranga Harbour. This data has been processed and analysed, providing us with more insight into current velocities, tidal asymmetries and sediment concentrations throughout the estuary. We have developed a calibrated hydrodynamic model for the whole estuary in Delft3D. Currently, we are using the field data in combination with the numerical model to explore the relationship between intertidal hypsometry, entrance constriction, tidal asymmetry and fetch alignedness for a number of sub-estuaries within Tauranga Harbour. A conference paper discussing preliminary findings, to be presented at Coasts & Ports 2017 in Cairns, has been submitted.