title: Assessment of the ecohydrological functioning of Otakairangi Wetland, Northland

authors: Campbell, David I.

abstract: Otakairangi is the largest wetland remnant on the floodplain of Northland’s Wairua River near Hikurangi. Extensive peat deposits many metres deep accumulated over thousands of years on the valley floors of the Otakairangi and Riponui valleys, as they did elsewhere within the former Hikurangi “Swamp”. The present‐day Otakairangi Wetland, with an area of 2.6 km², represents around 20% of its former extent.
This report provides an assessment of the ecohydrological functioning of Otakairangi Wetland in its current state, based on information gathered during a field survey, discussions with landowners, and other sources. The wetland, which contains representative communities of rare peatland plants, is a good candidate for restoration, including re‐introduction of the now locally extinct climax peatland plant species Sporadanthus ferrugineus.  
Hydrological modification to Otakairangi over the past century has included a deep central drain that has largely eliminated the natural diffuse flows of the former Otakairangi Stream as it traversed the wetland, and lowered water tables. Deep drains bordering the wetland’s south western and south eastern edges have also contributed to a modified hydrological regime. Over much of the past century water table lowering and frequent fires led to dominance by tall manuka, reduced peatland biodiversity, and severe peat degradation.
There is good evidence of fairly recent changes to Otakairangi’s vegetation towards greater dominance, especially in the east, of the key peat‐forming plant and ecosystem engineer Empodisma robustum, including vigorous growth of raw fibrous peat. As the dense manuka cover has declined,
Empodisma and allied plants have been able to naturally colonise and spread. Despite encouraging signs of some natural vegetation recovery within Otakairangi Wetland, there remain many unanswered questions about the trajectory of this recovery and the ongoing effects of drainage, as well as inundation by flood flows from the highly modified upstream catchment. Also, fire remains a constant threat that could reverse this trajectory. A number of key research questions are provided in this report that will guide the development of a research plan in support of ongoing restoration and monitoring efforts.
A number of restoration options are presented that should be considered at Otakairangi. These include minor to more major hydrological manipulations, which will require careful investigation and flow modelling in addition to working closely with affected landowners. As a first step, detailed surveys are required of drain invert levels and wetland and farmland surface levels. Monitoring of drain and wetland water tables should be initiated as soon as possible, to support research into wetland hydrological regimes and to further understand the spatial effect of water table lowering

text: Assessment of the ecohydrological functioning of Otakairangi Wetland, Northland Otakairangi is the largest wetland remnant on the floodplain of Northland’s Wairua River near Hikurangi. Extensive peat deposits many metres deep accumulated over thousands of years on the valley floors of the Otakairangi and Riponui valleys, as they did elsewhere within the former Hikurangi “Swamp”. The present‐day Otakairangi Wetland, with an area of 2.6 km², represents around 20% of its former extent.
This report provides an assessment of the ecohydrological functioning of Otakairangi Wetland in its current state, based on information gathered during a field survey, discussions with landowners, and other sources. The wetland, which contains representative communities of rare peatland plants, is a good candidate for restoration, including re‐introduction of the now locally extinct climax peatland plant species Sporadanthus ferrugineus.  
Hydrological modification to Otakairangi over the past century has included a deep central drain that has largely eliminated the natural diffuse flows of the former Otakairangi Stream as it traversed the wetland, and lowered water tables. Deep drains bordering the wetland’s south western and south eastern edges have also contributed to a modified hydrological regime. Over much of the past century water table lowering and frequent fires led to dominance by tall manuka, reduced peatland biodiversity, and severe peat degradation.
There is good evidence of fairly recent changes to Otakairangi’s vegetation towards greater dominance, especially in the east, of the key peat‐forming plant and ecosystem engineer Empodisma robustum, including vigorous growth of raw fibrous peat. As the dense manuka cover has declined,
Empodisma and allied plants have been able to naturally colonise and spread. Despite encouraging signs of some natural vegetation recovery within Otakairangi Wetland, there remain many unanswered questions about the trajectory of this recovery and the ongoing effects of drainage, as well as inundation by flood flows from the highly modified upstream catchment. Also, fire remains a constant threat that could reverse this trajectory. A number of key research questions are provided in this report that will guide the development of a research plan in support of ongoing restoration and monitoring efforts.
A number of restoration options are presented that should be considered at Otakairangi. These include minor to more major hydrological manipulations, which will require careful investigation and flow modelling in addition to working closely with affected landowners. As a first step, detailed surveys are required of drain invert levels and wetland and farmland surface levels. Monitoring of drain and wetland water tables should be initiated as soon as possible, to support research into wetland hydrological regimes and to further understand the spatial effect of water table lowering

year: 2017

title: A novel machine learning model to predict the moment capacity of cold-formed steel channel beams with edge-stiffened and un-stiffened web holes

authors: Dai, Yecheng

subjects: cold-formed steel

abstract: A novel machine learning model, eXtreme Gradient Boosting (XGBoost), was used for the purpose of evaluating the moment capacity of cold-formed steel (CFS) channel beams with edge-stiffened web holes subject to bending. A total of 1620 data points were generated for training the XGBoost model, using an elasto-plastic finite element model which was validated against 12 sets of test data taken from the existing literature. The R2 score of XGBoost predictions for the moment capacity was around 99%. The performance of current design equations was evaluated through the comparison of their results against those obtained from the XGBoost model. The moment capacities obtained from the XGBoost testing dataset were also compared with that determined from the existing design equations for un-stiffened holes (USH) and edge-stiffened holes (ESH). The moment capacities determined from the current design equations for USH and ESH were found to be excessively conservative by 38.3%, and unconservative by 36.2% on average, respectively. Therefore, new design equations were proposed based on the results of parametric study using the XGBoost model. In the detailed parametric analysis, the effects of web depth, section thickness, and beam length on the moment capacity of channel beams (CFSCB) with ESH were considered. From the results of XGBoost outputs, the absolute percentage error of new design equations for that based on the strengths of unperforated CFSCB was 8.78%, and for that based on the strengths of CFSCB with USH, the absolute percentage error was 13.7%. Additionally, a reliability analysis was performed to evaluate the accuracy of the proposed equations that were used to predict the moment capacity of CFS channel beams with ESH subject to bending. The reliability indices of all the proposed equations were greater than 2.5 which can be reliable as per the guidelines of AISI.

text: A novel machine learning model to predict the moment capacity of cold-formed steel channel beams with edge-stiffened and un-stiffened web holes A novel machine learning model, eXtreme Gradient Boosting (XGBoost), was used for the purpose of evaluating the moment capacity of cold-formed steel (CFS) channel beams with edge-stiffened web holes subject to bending. A total of 1620 data points were generated for training the XGBoost model, using an elasto-plastic finite element model which was validated against 12 sets of test data taken from the existing literature. The R2 score of XGBoost predictions for the moment capacity was around 99%. The performance of current design equations was evaluated through the comparison of their results against those obtained from the XGBoost model. The moment capacities obtained from the XGBoost testing dataset were also compared with that determined from the existing design equations for un-stiffened holes (USH) and edge-stiffened holes (ESH). The moment capacities determined from the current design equations for USH and ESH were found to be excessively conservative by 38.3%, and unconservative by 36.2% on average, respectively. Therefore, new design equations were proposed based on the results of parametric study using the XGBoost model. In the detailed parametric analysis, the effects of web depth, section thickness, and beam length on the moment capacity of channel beams (CFSCB) with ESH were considered. From the results of XGBoost outputs, the absolute percentage error of new design equations for that based on the strengths of unperforated CFSCB was 8.78%, and for that based on the strengths of CFSCB with USH, the absolute percentage error was 13.7%. Additionally, a reliability analysis was performed to evaluate the accuracy of the proposed equations that were used to predict the moment capacity of CFS channel beams with ESH subject to bending. The reliability indices of all the proposed equations were greater than 2.5 which can be reliable as per the guidelines of AISI.

year: 2022

title: Supervision and continuing professional development: Supervisors’ hopes for meaningful, supervision-supported CPD

authors: Flanagan, Paul G.

abstract: Continuing professional development (CPD) is now embedded into the New Zealand Association of Counsellors (NZAC) practices, such as its members’ supervision, processes for membership renewal and applications for annual practicing certificates. Since its implementation in 2017, a number of developments have been made to NZAC CPD requirements, and in 2020 the process went online. During the same year, six experienced supervisors participated in a small-scale study in which they were interviewed about their experiences of the CPD process and its effects on supervision. The research project was part of a postgraduate paper in professional supervision and worked to introduce and engage researcher-students, all of whom were experienced counselling practitioners, in a supervised collaborative project. This article offers a review of literature on CPD and supervision, and presents the new findings about supervisors’ hopes for meaningful, supervision-supported CPD. The findings highlighted limitations with current competencies for CPD and questioned these competencies as reflecting dominant Pākehā constructions of counselling and therefore, having effects for Māori practitioners. The study also revealed a tension between treating professional development as a requirement to be accounted for and hopes for supervision as a space to reflect on and shape future professional development.

text: Supervision and continuing professional development: Supervisors’ hopes for meaningful, supervision-supported CPD Continuing professional development (CPD) is now embedded into the New Zealand Association of Counsellors (NZAC) practices, such as its members’ supervision, processes for membership renewal and applications for annual practicing certificates. Since its implementation in 2017, a number of developments have been made to NZAC CPD requirements, and in 2020 the process went online. During the same year, six experienced supervisors participated in a small-scale study in which they were interviewed about their experiences of the CPD process and its effects on supervision. The research project was part of a postgraduate paper in professional supervision and worked to introduce and engage researcher-students, all of whom were experienced counselling practitioners, in a supervised collaborative project. This article offers a review of literature on CPD and supervision, and presents the new findings about supervisors’ hopes for meaningful, supervision-supported CPD. The findings highlighted limitations with current competencies for CPD and questioned these competencies as reflecting dominant Pākehā constructions of counselling and therefore, having effects for Māori practitioners. The study also revealed a tension between treating professional development as a requirement to be accounted for and hopes for supervision as a space to reflect on and shape future professional development.

year: 2021