title: Sedimentation And Hydrodynamics of Whitianga Estuary

authors: Reeve, Glen M.D

subjects: Hydrodynamics

abstract: Whitianga Estuary is a bayhead barrier type estuary located on the east of the Coromandel Peninsula, North Island, New Zealand. The catchment has undergone many land-use changes since pre-European settlement. In some areas of the catchment land-use has changed from native forest to grasslands to forestry and back to pasture. These changes in catchment land-use all contribute to increased sedimentation into the estuary. Development of the estuary itself has also occurred in recent times. Much growth has been focussed around the estuary due to Whitianga town-ship having a large boating community, and includes a 170 berth marina and wharf situated at
the tidal inlet entrance to the estuary. These, and the extensive canal development engineering works can have substantial impacts on the
sedimentation regime, and may modify tidal circulation, flushing, and sediment deposition within the estuary.

The principle aim of this research is to assess hydrodynamics and sedimentation of the estuary for future management and development purposes, and also to model different scenarios in order to determine the most cost effective, and least obtrusive design for a proposed boat-ramp and
approach channel near the marina.

To determine sedimentation rates, sediment cores from four locations were collected to depths of 1 m. Coring locations were chosen based on
preliminary model run results, selecting areas that appeared to be long-term sediment sinks of a stable nature. Cores were divided into 10 mm sections and prepared for 210Pb dating and heavy metal analysis, to make an assessment of the vertical sedimentation rates. Recent sedimentation rates were found to be as high as 9 mm/yr post-1950s and past sedimentation rates
as high as 30 mm/yr pre-1950s. The use of heavy metal analysis for dating proved difficult as the background levels of the conservative elements used to normalise results varied, making the geochemical analysis approach inappropriate.

As bathymetry is one of the most important aspects of modelling, a large amount of surveying was undertaken for this study. LiDAR, singlebeam data, and recent rectified aerial photographs were interpreted for the creation of a
bathymetric grid file to be used for hydrodynamic modelling of the estuary.

The 3DD numerical model was used to determine tidal flows and current velocities. From this initial hydrodynamic model a particle-tracking model was created to determine sediment transport pathways within the estuary. From the initial 20 m model it was then possible to create a number of nested model grids for the purpose of determining the best practice scenario for the
creation of a proposed boat ramp and associated approach channel near the harbour entrance. Hydrodynamic results suggest that residual circulation in Whitianga Estuary is nearly in balance, with a low ebb tidal domination present. Particle tracking results suggest that sediment entrained and carried into and within the estuary will accumulate on the intertidal flats. Sediment
transport modelling indicates that the impact of a proposed boat-ramp will result in sedimentation of the dredged approach channel due to reductions in residual and tidal velocities.

text: Sedimentation And Hydrodynamics of Whitianga Estuary Whitianga Estuary is a bayhead barrier type estuary located on the east of the Coromandel Peninsula, North Island, New Zealand. The catchment has undergone many land-use changes since pre-European settlement. In some areas of the catchment land-use has changed from native forest to grasslands to forestry and back to pasture. These changes in catchment land-use all contribute to increased sedimentation into the estuary. Development of the estuary itself has also occurred in recent times. Much growth has been focussed around the estuary due to Whitianga town-ship having a large boating community, and includes a 170 berth marina and wharf situated at
the tidal inlet entrance to the estuary. These, and the extensive canal development engineering works can have substantial impacts on the
sedimentation regime, and may modify tidal circulation, flushing, and sediment deposition within the estuary.

The principle aim of this research is to assess hydrodynamics and sedimentation of the estuary for future management and development purposes, and also to model different scenarios in order to determine the most cost effective, and least obtrusive design for a proposed boat-ramp and
approach channel near the marina.

To determine sedimentation rates, sediment cores from four locations were collected to depths of 1 m. Coring locations were chosen based on
preliminary model run results, selecting areas that appeared to be long-term sediment sinks of a stable nature. Cores were divided into 10 mm sections and prepared for 210Pb dating and heavy metal analysis, to make an assessment of the vertical sedimentation rates. Recent sedimentation rates were found to be as high as 9 mm/yr post-1950s and past sedimentation rates
as high as 30 mm/yr pre-1950s. The use of heavy metal analysis for dating proved difficult as the background levels of the conservative elements used to normalise results varied, making the geochemical analysis approach inappropriate.

As bathymetry is one of the most important aspects of modelling, a large amount of surveying was undertaken for this study. LiDAR, singlebeam data, and recent rectified aerial photographs were interpreted for the creation of a
bathymetric grid file to be used for hydrodynamic modelling of the estuary.

The 3DD numerical model was used to determine tidal flows and current velocities. From this initial hydrodynamic model a particle-tracking model was created to determine sediment transport pathways within the estuary. From the initial 20 m model it was then possible to create a number of nested model grids for the purpose of determining the best practice scenario for the
creation of a proposed boat ramp and associated approach channel near the harbour entrance. Hydrodynamic results suggest that residual circulation in Whitianga Estuary is nearly in balance, with a low ebb tidal domination present. Particle tracking results suggest that sediment entrained and carried into and within the estuary will accumulate on the intertidal flats. Sediment
transport modelling indicates that the impact of a proposed boat-ramp will result in sedimentation of the dredged approach channel due to reductions in residual and tidal velocities.

year: 2008

title: Discriminating Against New Classes: One-class versus Multi-class Classification

authors: Hempstalk, Kathryn

subjects: computer science

abstract: Many applications require the ability to identify data that is anomalous with respect to a target group of observations, in the sense of belonging to a new, previously unseen ‘attacker’ class. One possible approach to this kind of verification problem is one-class classification, learning a description of the target class concerned based solely on data from this class. However, if known non-target classes are available at training time, it is also possible to use standard multi-class or two-class classification, exploiting the negative data to infer a description of the target class. In this paper we assume that this scenario holds and investigate under what conditions multi-class and two-class Naïve Bayes classifiers are preferable to the corresponding one-class model when the aim is to identify examples from a new ‘attacker’ class. To this end we first identify a way of performing a fair comparison between the techniques concerned and present an adaptation of standard cross-validation. This is one of the main contributions of the paper. Based on the experimental results obtained, we then show under what conditions which group of techniques is likely to be preferable. Our main finding is that multi-class and two-class classification becomes preferable to one-class classification when a sufficiently large number of non-target classes is available.

text: Discriminating Against New Classes: One-class versus Multi-class Classification Many applications require the ability to identify data that is anomalous with respect to a target group of observations, in the sense of belonging to a new, previously unseen ‘attacker’ class. One possible approach to this kind of verification problem is one-class classification, learning a description of the target class concerned based solely on data from this class. However, if known non-target classes are available at training time, it is also possible to use standard multi-class or two-class classification, exploiting the negative data to infer a description of the target class. In this paper we assume that this scenario holds and investigate under what conditions multi-class and two-class Naïve Bayes classifiers are preferable to the corresponding one-class model when the aim is to identify examples from a new ‘attacker’ class. To this end we first identify a way of performing a fair comparison between the techniques concerned and present an adaptation of standard cross-validation. This is one of the main contributions of the paper. Based on the experimental results obtained, we then show under what conditions which group of techniques is likely to be preferable. Our main finding is that multi-class and two-class classification becomes preferable to one-class classification when a sufficiently large number of non-target classes is available.

year: 2008

title: A reflective account of successful leadership: Māori special character secondary boarding schools.

authors: McAllister, Theresa

abstract: This thesis explores the leadership and Māori student achievement in Māori boarding schools taking into account cultural contexts, environments and the leadership ideologies around educational leadership. What are the leadership practices in Māori boarding schools that have made a difference for Māori student achievement? I argue that, Māori secondary boarding schools continue to offer an educational framework whereby Māori students achieve as Maori.
In order to better understand the philosophies and goals of those early Māori boarding school leaders through to the present time I have researched a sample of current leaders within those boarding schools. This research interest arose many years ago when I first realised that there was a significant gap in Māori student educational achievement compared to non-Māori. What was also realised was that few people understood the contribution that Māori boarding schools have played in Māori student achievement and success over many decades. While some people had heard of Māori boarding schools, not a great deal was really known about what Māori boarding schools delivered in terms of education for Māori and Māori culture. What is apparent from an historical perspective is that Māori boarding schools have contributed to the retention of Māori culture, language and identity resulting in student achievement. This is a result of what successful leadership has provided for Māori students to achieve.
Student achievement is a direct result of leadership. In a Māori boarding school setting, achievement is multifaceted. For Māori secondary boarding schools, achievement is taken from three perspectives: Christian, Māori and Academic. Flowing down from those three perspectives is the holistic wellbeing of students’, mind, body and soul, while recognizing and including whānau, hapū and iwi. Therefore, this research investigates the leadership practices in Māori boarding schools that have made a difference for Māori student achievement.

text: A reflective account of successful leadership: Māori special character secondary boarding schools. This thesis explores the leadership and Māori student achievement in Māori boarding schools taking into account cultural contexts, environments and the leadership ideologies around educational leadership. What are the leadership practices in Māori boarding schools that have made a difference for Māori student achievement? I argue that, Māori secondary boarding schools continue to offer an educational framework whereby Māori students achieve as Maori.
In order to better understand the philosophies and goals of those early Māori boarding school leaders through to the present time I have researched a sample of current leaders within those boarding schools. This research interest arose many years ago when I first realised that there was a significant gap in Māori student educational achievement compared to non-Māori. What was also realised was that few people understood the contribution that Māori boarding schools have played in Māori student achievement and success over many decades. While some people had heard of Māori boarding schools, not a great deal was really known about what Māori boarding schools delivered in terms of education for Māori and Māori culture. What is apparent from an historical perspective is that Māori boarding schools have contributed to the retention of Māori culture, language and identity resulting in student achievement. This is a result of what successful leadership has provided for Māori students to achieve.
Student achievement is a direct result of leadership. In a Māori boarding school setting, achievement is multifaceted. For Māori secondary boarding schools, achievement is taken from three perspectives: Christian, Māori and Academic. Flowing down from those three perspectives is the holistic wellbeing of students’, mind, body and soul, while recognizing and including whānau, hapū and iwi. Therefore, this research investigates the leadership practices in Māori boarding schools that have made a difference for Māori student achievement.

year: 2016