title: Assessment of the potential interactions of an oil spill with sediments on the west coast of New Zealand

authors: Park, Justine Ariki

subjects: New Zealand

abstract: There are limited data available on the interaction of spilt oil and sediment commonly found on New Zealand beaches and the data available have been obtained for intermediate state east coast beaches. The west coast of New Zealand’s north island generally has higher energy dissipative to ultra-dissipative beaches.
Physical mixing of oil with beach sediment depends on both the depth of penetration into sediment and surface elevation changes. This study assessed physical mixing depths on three contrasting beaches; a highly dissipative open coast beach, a tidally controlled beach and a sheltered estuarine beach. Estimated and measured forcing conditions were correlated with vertical maxima of disturbance. The use of spatially discrete, non-averaged measurements of the depth of disturbance allowed spatial variation to be interpreted. Surface elevation changes were evaluated in conjunction with depth of disturbance measurements which allowed morphological features to be correlated with mixing depths alongshore and crosshore. Measurement of large scale morphological change also allowed interpretation of maximum potential oil burial depths. Oil settling experiments were carried out to evaluate oil settling times and behaviours.
Morphological response is a function of changing incident wave regimes, currents, pre-existing morphology and tidal range. Large-scale erosive events have been recorded and observed at Ngarunui Beach that change the bed elevation in excess of 5 m, while small bed level variation occurs on the scale of decimetres during each tidal cycle. It was found that disturbance depths varied substantially in the cross-shore and longshore during all experiments. Wave breaking was determined to be the main mechanism for sediment mixing. Hence, the significant variation across the beach is attributed to the complex morphology of the beach.
The areas most exposed to wave breaking exhibited the most disturbance at Ngarunui Beach; larger values of disturbance in the mid intertidal zone at Ngarunui Beach correspond with the zone that is most exposed to wave breaking. Cross-shore bimodal distributions of mixing were not observed. Swash processes dominated in the high intertidal zone with accretion occurring during spring tides however swash processes have limited effects on this beach, with mixing values greatly reduced under these processes. A tidally controlled beach located within the estuary close to the harbour entrance experienced significantly larger mixing depth values when no waves were present due in part to stronger currents and greater inundation during spring tides. The sheltered estuarine beach within the harbour experienced minimal mixing depths.
Values for the vertical limits of the mixing layer exceed 40 % of the breaking wave height, Hb, for reflective beaches, while on dissipative beaches, theory predicts that the values will be extremely reduced as wave energies are dispersed across wide surf zones. However, in this study, disturbance values were higher than those previously reported in the literature for dissipative beaches. Using parameters for wave obliquity and beach slope, the average mixing depths could be somewhat predicted using the method of Bertin et al. (2008). Significant variation between and within locations means that use of this model could significantly underestimate depths of disturbance and hence oil burial on the west coast of New Zealand’s North Island.
Assessment of the interactions between oil and sediment in the laboratory indicated preferential bonding of oil with heavy minerals common on west coast New Zealand beaches. This implies that oil is more likely to form stable oil-mineral aggregates on west coast beaches compared to east coast beaches with low heavy mineral content.

text: Assessment of the potential interactions of an oil spill with sediments on the west coast of New Zealand There are limited data available on the interaction of spilt oil and sediment commonly found on New Zealand beaches and the data available have been obtained for intermediate state east coast beaches. The west coast of New Zealand’s north island generally has higher energy dissipative to ultra-dissipative beaches.
Physical mixing of oil with beach sediment depends on both the depth of penetration into sediment and surface elevation changes. This study assessed physical mixing depths on three contrasting beaches; a highly dissipative open coast beach, a tidally controlled beach and a sheltered estuarine beach. Estimated and measured forcing conditions were correlated with vertical maxima of disturbance. The use of spatially discrete, non-averaged measurements of the depth of disturbance allowed spatial variation to be interpreted. Surface elevation changes were evaluated in conjunction with depth of disturbance measurements which allowed morphological features to be correlated with mixing depths alongshore and crosshore. Measurement of large scale morphological change also allowed interpretation of maximum potential oil burial depths. Oil settling experiments were carried out to evaluate oil settling times and behaviours.
Morphological response is a function of changing incident wave regimes, currents, pre-existing morphology and tidal range. Large-scale erosive events have been recorded and observed at Ngarunui Beach that change the bed elevation in excess of 5 m, while small bed level variation occurs on the scale of decimetres during each tidal cycle. It was found that disturbance depths varied substantially in the cross-shore and longshore during all experiments. Wave breaking was determined to be the main mechanism for sediment mixing. Hence, the significant variation across the beach is attributed to the complex morphology of the beach.
The areas most exposed to wave breaking exhibited the most disturbance at Ngarunui Beach; larger values of disturbance in the mid intertidal zone at Ngarunui Beach correspond with the zone that is most exposed to wave breaking. Cross-shore bimodal distributions of mixing were not observed. Swash processes dominated in the high intertidal zone with accretion occurring during spring tides however swash processes have limited effects on this beach, with mixing values greatly reduced under these processes. A tidally controlled beach located within the estuary close to the harbour entrance experienced significantly larger mixing depth values when no waves were present due in part to stronger currents and greater inundation during spring tides. The sheltered estuarine beach within the harbour experienced minimal mixing depths.
Values for the vertical limits of the mixing layer exceed 40 % of the breaking wave height, Hb, for reflective beaches, while on dissipative beaches, theory predicts that the values will be extremely reduced as wave energies are dispersed across wide surf zones. However, in this study, disturbance values were higher than those previously reported in the literature for dissipative beaches. Using parameters for wave obliquity and beach slope, the average mixing depths could be somewhat predicted using the method of Bertin et al. (2008). Significant variation between and within locations means that use of this model could significantly underestimate depths of disturbance and hence oil burial on the west coast of New Zealand’s North Island.
Assessment of the interactions between oil and sediment in the laboratory indicated preferential bonding of oil with heavy minerals common on west coast New Zealand beaches. This implies that oil is more likely to form stable oil-mineral aggregates on west coast beaches compared to east coast beaches with low heavy mineral content.

year: 2016

title: Prospective actuarial risk assessment: A comparison of five risk assessment instruments in different sexual offender subtypes

authors: Rettenberger, Martin

subjects: sexual offending

abstract: This study examines the predictive validity of the most commonly used risk assessment instruments for sexual offenders: Static-99, Rapid Risk Assessment for Sexual Offense Recidivism, Sex Offender Risk Appraisal Guide, Sexual Violence Risk—20, and Psychopathy Checklist—Revised in a prospective research design. Although risk assessment is part of a regime leading to various efforts to reduce risk by treatment and aftercare, all instruments show good predictive validity. However, depending on the instrument, recidivism category, and subgroup, the predictive accuracy varies markedly. Furthermore, the authors fail to demonstrate predictive validity for sexual violent reoffences—for the whole sample and for all subgroups. The results, nevertheless, support the utility and predictive validity of actuarial risk assessment complementary to treatment efforts to reduce risk. On the other hand, forensic practitioners have to be aware of the limitations of actuarial risk assessment methods, in particular as regards to variable predictive accuracy for different sexual offender subgroups and reoffence categories.

text: Prospective actuarial risk assessment: A comparison of five risk assessment instruments in different sexual offender subtypes This study examines the predictive validity of the most commonly used risk assessment instruments for sexual offenders: Static-99, Rapid Risk Assessment for Sexual Offense Recidivism, Sex Offender Risk Appraisal Guide, Sexual Violence Risk—20, and Psychopathy Checklist—Revised in a prospective research design. Although risk assessment is part of a regime leading to various efforts to reduce risk by treatment and aftercare, all instruments show good predictive validity. However, depending on the instrument, recidivism category, and subgroup, the predictive accuracy varies markedly. Furthermore, the authors fail to demonstrate predictive validity for sexual violent reoffences—for the whole sample and for all subgroups. The results, nevertheless, support the utility and predictive validity of actuarial risk assessment complementary to treatment efforts to reduce risk. On the other hand, forensic practitioners have to be aware of the limitations of actuarial risk assessment methods, in particular as regards to variable predictive accuracy for different sexual offender subgroups and reoffence categories.

year: 2010

title: Maori at Te Aroha after the opening of the goldfield in 1880 (mostly through Pakeha eyes)

authors: Hart, Philip

abstract: As the Maori population continued to decline, the aged rangatira admired by Pakeha (even including those who had fought against the Crown) gradually died off, to be replaced by Maori more noted for their drinking and occasional violence than their prestige. Although concerts and haka were popular with many Pakeha, much Maori behaviour was mocked, including by children. Many Maori were seen as being unsophisticated, unable to express themselves properly in English, and prone to drunkenness and laziness, whereas those who adopted Pakeha ways were praised.
Some Pakeha sympathized with poverty-stricken Maori and regretted the decline of their language. There were many examples of close and friendly relations and of Maori assisting Pakeha in trouble, but in general they lived geographically separate lives. To earn money, Maori were forced to work at road making, timber cutting, gum digging, and farming what land remained in their possession. Most Maori struggled financially, their limited resources being stretched by holding expensive tangi and entertaining visitors – resulting in more land sales. They used the court system to defend their economic interests.
Ngati Rahiri (including supporters of the Kingitanga) were seen as ‘loyal’ to the Crown, and visiting Maori kings received kindly treatment from Pakeha as well as from Maori. 
Poor health prompted some government assistance, but poor housing remained, although some attempts were made to improve it (partly to protect Pakeha from diseases). Before the twentieth century only a few children, mostly ‘half-castes’, were educated. Most Ngati Rahiri were members of the Church of England before being attracted by the new Mormon faith.
Ngati Rahiri participated with Pakeha in horse races, sporting contests, and, especially, rugby, and a few joined the Volunteers. Much less desirable to most residents was their heavy drinking (encouraged by some publicans and their Pakeha drinking buddies), and occasional fights, very occasionally with Pakeha. Overall, Pakeha ways, both good and bad, of necessity were adopted, and Ngati Rahiri became inextricably a subordinate part of the Pakeha community, although still retaining some distinctive features. 

 (Note: Unless otherwise indicated, all those named in this paper, both Maori and Pakeha, were shareholders in claims in the Te Aroha district.)

text: Maori at Te Aroha after the opening of the goldfield in 1880 (mostly through Pakeha eyes) As the Maori population continued to decline, the aged rangatira admired by Pakeha (even including those who had fought against the Crown) gradually died off, to be replaced by Maori more noted for their drinking and occasional violence than their prestige. Although concerts and haka were popular with many Pakeha, much Maori behaviour was mocked, including by children. Many Maori were seen as being unsophisticated, unable to express themselves properly in English, and prone to drunkenness and laziness, whereas those who adopted Pakeha ways were praised.
Some Pakeha sympathized with poverty-stricken Maori and regretted the decline of their language. There were many examples of close and friendly relations and of Maori assisting Pakeha in trouble, but in general they lived geographically separate lives. To earn money, Maori were forced to work at road making, timber cutting, gum digging, and farming what land remained in their possession. Most Maori struggled financially, their limited resources being stretched by holding expensive tangi and entertaining visitors – resulting in more land sales. They used the court system to defend their economic interests.
Ngati Rahiri (including supporters of the Kingitanga) were seen as ‘loyal’ to the Crown, and visiting Maori kings received kindly treatment from Pakeha as well as from Maori. 
Poor health prompted some government assistance, but poor housing remained, although some attempts were made to improve it (partly to protect Pakeha from diseases). Before the twentieth century only a few children, mostly ‘half-castes’, were educated. Most Ngati Rahiri were members of the Church of England before being attracted by the new Mormon faith.
Ngati Rahiri participated with Pakeha in horse races, sporting contests, and, especially, rugby, and a few joined the Volunteers. Much less desirable to most residents was their heavy drinking (encouraged by some publicans and their Pakeha drinking buddies), and occasional fights, very occasionally with Pakeha. Overall, Pakeha ways, both good and bad, of necessity were adopted, and Ngati Rahiri became inextricably a subordinate part of the Pakeha community, although still retaining some distinctive features. 

 (Note: Unless otherwise indicated, all those named in this paper, both Maori and Pakeha, were shareholders in claims in the Te Aroha district.)

year: 2016