title: Reduction of water and bed levels in the lower Waikato River

authors: Wo, You Gu

subjects: Waikato River

abstract: The major aims of this thesis are to determine the historical qualitative and quantitative reduction in water and bed levels of the lower Waikato River, to identify probable factors influencing the reduction, and to predict the future water and bed levels at Huntly in relation to the Huntly Power Station management
Sediments in the Waikato River are composed of gravelly pumiceous sands. In terms of the mean and median grain sizes, generally sands dominate the lower river b~ from the river mouth to the cross section at about 100 km upstream of the mouth, while gravels dominate the bed upstream onward. A hiatus in the longitudinal mean and median grain size distributions from sand to gravel is apparent around Horotiu. In the Waipa River, the texture of bed materials was found to be similar but probably finer to those in the lower parts of the Waikato River.
On the basis that ∂n / ∂Q= ∂W/ ∂Q =∂S / ∂Q=0, where n, W, S and Q are, respectively, Manning's coefficient, width, energy slope and discharge, water level of each gauging can be adjusted to one for an index flow of 350 m³/s ( WLQ₌₃₅₀ ). Further assuming that ∂n / ∂T = ∂W / ∂T = ∂S / ∂T=0 where T is time, variations in the time series of WLQ₌₃₅₀ represent the mean bed level changes over time. These assumptions seem to be acceptable for those gauging data within a certain range of discharges in the lower Waikato River.
A quantitative analysis of the available river survey data, water level profile measurements, and gauging records has indicated that, in general, there was a continuous trend of reduction in water and bed levels on the lower Waikato River since the 1960s. The reasons for these reductions likely include sand mining operation along the river, consequent disturbance of the river bed surface, long term sand extraction around Mercer and further downstream, upstream effects of the significant bed level lowering at Mercer, and downstream effects of the 1947 Karapiro Dam closure.
Analysis of river bulk volume changes suggested that the amount of bedload transported into the river downstream of Ngaruawahia was about 160 000±24 000 m3/yr between 1964-1989. Nearly two-thirds of this was contributed by the bed materials stored in the upstream Waikato River course by an analysis of data from 1974-1989, and the remainder by the Waipa River and the catchment yield from the Hamilton basin.
Two disparate time scales for water and bedload movements in practice result in singularperturbation characteristics of the system. With a quasi-steady flow approach, linearization of the water and bedload movement system produces a hyperbolic equation or even a parabolic equation (uniform flow). The parabolic equation is a good approximation of the hyperbolic equation under the condition of large values of time or a large distance from the original disturbance. Variations along the Waikato River of an average mean bed level within a certain length of channel are expected to be small. Therefore the linear models can be applied. In the domain between 48.25-94.45 km upstream of the Waikato River mouth, the parabolic model has been used numerically to predict the future bed levels at Huntly in December 2040 for different scenarios. Potential effects on operation of the present cooling water system have been assessed for given discharges at that time.
The ratio of river width to water depth for the formation of alternate bars at the Huntly Railway Bridge has been found to be exceeding 100 by an analysis of the gauging data at this site and at the Ngaruawahia Cableway. This critical width-depth ratio, 100, is much bigger than those suggested in the literature. The corresponding conditions of discharge and mean water depth are, respectively, less than about 350 m³/s and 2.30 m. However further research is required to confirm these conclusions.

text: Reduction of water and bed levels in the lower Waikato River The major aims of this thesis are to determine the historical qualitative and quantitative reduction in water and bed levels of the lower Waikato River, to identify probable factors influencing the reduction, and to predict the future water and bed levels at Huntly in relation to the Huntly Power Station management
Sediments in the Waikato River are composed of gravelly pumiceous sands. In terms of the mean and median grain sizes, generally sands dominate the lower river b~ from the river mouth to the cross section at about 100 km upstream of the mouth, while gravels dominate the bed upstream onward. A hiatus in the longitudinal mean and median grain size distributions from sand to gravel is apparent around Horotiu. In the Waipa River, the texture of bed materials was found to be similar but probably finer to those in the lower parts of the Waikato River.
On the basis that ∂n / ∂Q= ∂W/ ∂Q =∂S / ∂Q=0, where n, W, S and Q are, respectively, Manning's coefficient, width, energy slope and discharge, water level of each gauging can be adjusted to one for an index flow of 350 m³/s ( WLQ₌₃₅₀ ). Further assuming that ∂n / ∂T = ∂W / ∂T = ∂S / ∂T=0 where T is time, variations in the time series of WLQ₌₃₅₀ represent the mean bed level changes over time. These assumptions seem to be acceptable for those gauging data within a certain range of discharges in the lower Waikato River.
A quantitative analysis of the available river survey data, water level profile measurements, and gauging records has indicated that, in general, there was a continuous trend of reduction in water and bed levels on the lower Waikato River since the 1960s. The reasons for these reductions likely include sand mining operation along the river, consequent disturbance of the river bed surface, long term sand extraction around Mercer and further downstream, upstream effects of the significant bed level lowering at Mercer, and downstream effects of the 1947 Karapiro Dam closure.
Analysis of river bulk volume changes suggested that the amount of bedload transported into the river downstream of Ngaruawahia was about 160 000±24 000 m3/yr between 1964-1989. Nearly two-thirds of this was contributed by the bed materials stored in the upstream Waikato River course by an analysis of data from 1974-1989, and the remainder by the Waipa River and the catchment yield from the Hamilton basin.
Two disparate time scales for water and bedload movements in practice result in singularperturbation characteristics of the system. With a quasi-steady flow approach, linearization of the water and bedload movement system produces a hyperbolic equation or even a parabolic equation (uniform flow). The parabolic equation is a good approximation of the hyperbolic equation under the condition of large values of time or a large distance from the original disturbance. Variations along the Waikato River of an average mean bed level within a certain length of channel are expected to be small. Therefore the linear models can be applied. In the domain between 48.25-94.45 km upstream of the Waikato River mouth, the parabolic model has been used numerically to predict the future bed levels at Huntly in December 2040 for different scenarios. Potential effects on operation of the present cooling water system have been assessed for given discharges at that time.
The ratio of river width to water depth for the formation of alternate bars at the Huntly Railway Bridge has been found to be exceeding 100 by an analysis of the gauging data at this site and at the Ngaruawahia Cableway. This critical width-depth ratio, 100, is much bigger than those suggested in the literature. The corresponding conditions of discharge and mean water depth are, respectively, less than about 350 m³/s and 2.30 m. However further research is required to confirm these conclusions.

year: 1994

title: Prediction of Oestrus in Dairy Cows: An Application of Machine Learning to Skewed Data

authors: Lynam, Adam David

subjects: machine learning

abstract: The Dairy industry requires accurate detection of oestrus(heat) in dairy cows to maximise output of the animals. Traditionally this is a process dependant on human observation and interpretation of the various signs of heat. Many areas of the dairy industry can be automated, however the detection of oestrus is an area that still requires human experts.
This thesis investigates the application of Machine Learning classification techniques, on dairy cow milking data provided by the Livestock Improvement Corporation, to predict oestrus. The usefulness of various ensemble learning algorithms such as Bagging and Boosting are explored as well as specific skewed data techniques.
An empirical study into the effectiveness of classifiers designed to target skewed data is included as a significant part of the investigation. Roughly Balanced Bagging and the novel Under Bagging classifiers are explored in considerable detail and found to perform quite favourably over the SMOTE technique for the datasets selected. This study uses non-dairy, commonplace, Machine Learning datasets; many of which are found in the UCI Machine Learning Repository.

text: Prediction of Oestrus in Dairy Cows: An Application of Machine Learning to Skewed Data The Dairy industry requires accurate detection of oestrus(heat) in dairy cows to maximise output of the animals. Traditionally this is a process dependant on human observation and interpretation of the various signs of heat. Many areas of the dairy industry can be automated, however the detection of oestrus is an area that still requires human experts.
This thesis investigates the application of Machine Learning classification techniques, on dairy cow milking data provided by the Livestock Improvement Corporation, to predict oestrus. The usefulness of various ensemble learning algorithms such as Bagging and Boosting are explored as well as specific skewed data techniques.
An empirical study into the effectiveness of classifiers designed to target skewed data is included as a significant part of the investigation. Roughly Balanced Bagging and the novel Under Bagging classifiers are explored in considerable detail and found to perform quite favourably over the SMOTE technique for the datasets selected. This study uses non-dairy, commonplace, Machine Learning datasets; many of which are found in the UCI Machine Learning Repository.

year: 2009

title: Supervision as cultural partnership: Contributions to dialogue

authors: Crocket, Kathie

abstract: The term cultural supervision has been coined as part of a strategy that implicates supervision in the support and development of culturally appropriate therapeutic practice. In Aotearoa New Zealand particular focus has been given to supervision where the client is Māori and the practitioner is a member of the dominant Pākehā culture particularly, or of other non-Māori cultures. However, while the phrase cultural supervision has entered common professional parlance, the practice has had little research attention in counselling/psychotherapy in New Zealand. Cultural supervision appears to encompass a range of understandings, and there is no clear agreement about practice implications. It is unclear what alignment there is between aspirations, regulations, and practice. This article reports on an exploratory qualitative study that investigated how supervision might work in supporting culturally appropriate counselling practice in Aotearoa New Zealand. The study’s findings are presented as a multi-voiced dialogue. This arts-based representational practice enacts the uncertainties of post-colonial experience. Its intention is to make assumptions, ideas, and practices available for discussion. Its contribution is to join current dialogue about supervision and culture, and to raise further questions about how supervision and culturally appropriate practice come together.

text: Supervision as cultural partnership: Contributions to dialogue The term cultural supervision has been coined as part of a strategy that implicates supervision in the support and development of culturally appropriate therapeutic practice. In Aotearoa New Zealand particular focus has been given to supervision where the client is Māori and the practitioner is a member of the dominant Pākehā culture particularly, or of other non-Māori cultures. However, while the phrase cultural supervision has entered common professional parlance, the practice has had little research attention in counselling/psychotherapy in New Zealand. Cultural supervision appears to encompass a range of understandings, and there is no clear agreement about practice implications. It is unclear what alignment there is between aspirations, regulations, and practice. This article reports on an exploratory qualitative study that investigated how supervision might work in supporting culturally appropriate counselling practice in Aotearoa New Zealand. The study’s findings are presented as a multi-voiced dialogue. This arts-based representational practice enacts the uncertainties of post-colonial experience. Its intention is to make assumptions, ideas, and practices available for discussion. Its contribution is to join current dialogue about supervision and culture, and to raise further questions about how supervision and culturally appropriate practice come together.

year: 2015