Hydrodynamic and sediment transport numerical modelling and applications at Tairua Estuary, New Zealand
type: CreativeWork
description: Tairua Estuary is a partially mixed estuary located on the east coast of the Coromandel Peninsula, North Island, New Zealand. Like many estuaries worldwide, Tairua Estuary is experiencing rapid sedimentation, which is causing a range of environmental and management issues. This study was undertaken to develop a combined hydrodynamic and sediment transport numerical model as a tool for improving management of sedimentation issues within Tairua Estuary. Two field campaigns were undertaken in July 2010 and June 2011 to obtain calibration and verification datasets for two suites of numerical models – DHI MIKE and ASR 3DD – that were both used for hydrodynamic and sediment transport simulations to allow comparisons of the model suites. Additional models were used to simulate additional processes such as oil dispersal. Observations and numerical modelling showed the tidal wave was distorted as it propagated into the Tairua Estuary, becoming increasingly asymmetrical with distance from the entrance. The tidal wave underwent more distortion during spring tides than during neap tides, resulting in the influx of more oceanic water in the upper Tairua Estuary during a spring tidal cycle, causing a greater increase of salinity. The changing tidal distortion with tidal range also resulted in spring tides being flood dominated and neap tides being ebb dominated. The fate of fine sediments introduced into the lower estuary was, therefore, dependant on the state of the spring-neap cycle, with spring tides favouring deposition in the upper estuary, and neap tides favouring export to the continental shelf. The effects of tidal behaviour in the estuary were modified by river discharge, with increasing discharge resulting in increased ebb dominance and export of sediment from the estuary. Further, as river discharge increased, the estuary became more stratified, particularly during periods of low tidal velocities. However, areas of Tairua Estuary with tidal current velocities higher th…
abstract: Tairua Estuary is a partially mixed estuary located on the east coast of the Coromandel Peninsula, North Island, New Zealand. Like many estuaries worldwide, Tairua Estuary is experiencing rapid sedimentation, which is causing a range of environmental and management issues. This study was undertaken to develop a combined hydrodynamic and sediment transport numerical model as a tool for improving management of sedimentation issues within Tairua Estuary. Two field campaigns were undertaken in July 2010 and June 2011 to obtain calibration and verification datasets for two suites of numerical models – DHI MIKE and ASR 3DD – that were both used for hydrodynamic and sediment transport simulations to allow comparisons of the model suites. Additional models were used to simulate additional processes such as oil dispersal. Observations and numerical modelling showed the tidal wave was distorted as it propagated into the Tairua Estuary, becoming increasingly asymmetrical with distance from the entrance. The tidal wave underwent more distortion during spring tides than during neap tides, resulting in the influx of more oceanic water in the upper Tairua Estuary during a spring tidal cycle, causing a greater increase of salinity. The changing tidal distortion with tidal range also resulted in spring tides being flood dominated and neap tides being ebb dominated. The fate of fine sediments introduced into the lower estuary was, therefore, dependant on the state of the spring-neap cycle, with spring tides favouring deposition in the upper estuary, and neap tides favouring export to the continental shelf. The effects of tidal behaviour in the estuary were modified by river discharge, with increasing discharge resulting in increased ebb dominance and export of sediment from the estuary. Further, as river discharge increased, the estuary became more stratified, particularly during periods of low tidal velocities. However, areas of Tairua Estuary with tidal current velocities higher th…
author: Liu, Zhi
keywords: estuarine process, sediment transport, numerical modelling, sea level rise, seiche
license: https://researchcommons.waikato.ac.nz/bitstreams/2a1c9dab-7db5-4c4d-a6a9-e75733779206/download
date published: 2014
date modified: 2026-07-24T05:57:33Z
provider: University Waikato
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Waikato