The hydrodynamic evolution of the Maketū Estuary after the re-diversion of the Kaituna River
type: CreativeWork
description: The Maketū Estuary and lower Kaituna River located in the Bay of Plenty, Aotearoa, New Zealand have undergone anthropic disturbances since late 1800s, including land reclamation, river diversion and re-diversion, and modifications to the river channels and estuary tidal inlet. This has resulted in estuarine degradation, as is a common issue worldwide. Globally different approaches to estuary restoration have aimed at mitigating the adverse impacts of estuarine degradation. However, there are still gaps in restoration frameworks and how the success of the scheme is evaluated that mean there is no ready-made solution to the issues at Maketū. This thesis examines the important role of the hydrodynamic processes (including water quality) that govern the overall physical response of Maketū Estuary to two stages of partial re-diversion of the Kaituna River into the estuary. The assessment of this physical response highlighted the necessity of a proper framework in which restoration attempts, such as at Maketū are evaluated. Field time series data were collected before and after two stages of river re-diversion, Stage 1 in 2020 and Stage 2 in 2021, each over a span of a month, to record the immediate response of the estuary to the added freshwater flows. Freshwater flow into the estuary was constrained to approximately 4 hours during flood tides when the water level In the Kaituna River was at least 40 mm higher than the upper Maketū Estuary. The control gates also operate as a flood control scheme, so they remain shut if there is flood risk causing all the flood volume to discharge directly to the sea through Te Tumu Cut river mouth. The field data were obtained using Aquadopp ADPs, RBR Maestros, RBR Concertos, and Solinst water level loggers at seven different sites throughout the estuary and the Kaituna River. A hydrographic survey of the estuary using RTK-GNSS was undertaken and combined with LiDAR to produce a bathymetric map of the estuary and Lower Kaituna River. Co…
abstract: The Maketū Estuary and lower Kaituna River located in the Bay of Plenty, Aotearoa, New Zealand have undergone anthropic disturbances since late 1800s, including land reclamation, river diversion and re-diversion, and modifications to the river channels and estuary tidal inlet. This has resulted in estuarine degradation, as is a common issue worldwide. Globally different approaches to estuary restoration have aimed at mitigating the adverse impacts of estuarine degradation. However, there are still gaps in restoration frameworks and how the success of the scheme is evaluated that mean there is no ready-made solution to the issues at Maketū. This thesis examines the important role of the hydrodynamic processes (including water quality) that govern the overall physical response of Maketū Estuary to two stages of partial re-diversion of the Kaituna River into the estuary. The assessment of this physical response highlighted the necessity of a proper framework in which restoration attempts, such as at Maketū are evaluated. Field time series data were collected before and after two stages of river re-diversion, Stage 1 in 2020 and Stage 2 in 2021, each over a span of a month, to record the immediate response of the estuary to the added freshwater flows. Freshwater flow into the estuary was constrained to approximately 4 hours during flood tides when the water level In the Kaituna River was at least 40 mm higher than the upper Maketū Estuary. The control gates also operate as a flood control scheme, so they remain shut if there is flood risk causing all the flood volume to discharge directly to the sea through Te Tumu Cut river mouth. The field data were obtained using Aquadopp ADPs, RBR Maestros, RBR Concertos, and Solinst water level loggers at seven different sites throughout the estuary and the Kaituna River. A hydrographic survey of the estuary using RTK-GNSS was undertaken and combined with LiDAR to produce a bathymetric map of the estuary and Lower Kaituna River. Co…
author: Razzaghi, Mojgan
license: https://researchcommons.waikato.ac.nz/bitstreams/f2a0a18d-2436-4633-9297-8e9ef69ec0d8/download
date published: 2023
date modified: 2026-07-24T05:57:30Z
provider: University Waikato
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: The University of Waikato