title: Detecting signals of climatic shifts and land use change from precipitation and river discharge variations: The Whanganui and Waikato catchments

authors: Qiao, Ying

subjects: change-points

abstract: The Whanganui and Waikato river catchments have somewhat different degrees of exposure to the westerly wind systems. It is of interest to determine whether the two regions have similar times of occurrence of any concurrent shifts in river discharge and rainfall, with particular reference to mean value changes. Concurrent rainfall and runoff shifts are indicative of climatic variation but catchment land use changes (which will influence only discharge change) have also been occurring in both catchments, particularly with respect to forest planting or forest clearance. This thesis gives a summary of both climatic and land use change effects within the two catchments. If it happens that both catchments have similar climatic change-points then the data can be combined to provide a more robust framework for future water right specifications in both regions. Also, any similar responses to land use change may enable some degree of anticipation as to how future land use changes might lead to similar discharge responses.        
     
Change-points in river and rainfall time series flows were determined by an objective approach to detect breaks of slope in cumulative mass plots. Using repeated least squares fitting of piecewise linear segments, time points of maximum difference are determined as measured by the minimum least-squares in 2-segment fitting. Randomisation of time ordering of the original data was then employed to check that changes in the cumulative plots were statistically significant. Many significant but minor shifts were detected but a number of the shifts shown evidently in the rainfall and runoff cumulative mass plots. A set of change-points due to land management impacts were identified as discharge changes in the absence of concurrent rainfall changes. Rainfall-runoff linear relationship changes associate with changes in discharge time series.       

Change-points in rainfall and runoff times were detected at 44 flow gauges and 59 rainfall sites. There is some indication of a degree of natural geographic grouping with spatial correlation of times of discharge change. The times of the detected changes tend to cluster, with similar times for the same sign of change toward either greater or lower values of rainfall and discharge. The alternation of positive and negative signs is interesting as it was found 1981 and 1998 were times of negative shifts, while 1988 and 1994/1995 were times of positive shifts. Almost over the whole Waikato and Whanganui region, the changes in rainfall and runoff  appears to relate to El Nino and La Nino events, which is of practical interest for water right considerations. The driver of the shifts in rainfall pattern was found to be the changes in high rainfall events, which can change the rainfall-runoff linear relationship in some areas.             

The land use component of some of the shifts was evaluated also and found only in 10 of the 44 flow gauges. The type of the land-use can be categorized into three groups: hydropower diversion, flood control system and afforestation. Within the study catchments, the impact of hydropower diversion is more significant than the other two types. With regards to the Whanganui catchments, the operation of the Tongariro power scheme from 1973 decreased low-flow by 89% in the Wahkapapa River and around 42% and 26% of the flow in the Whanganui River at Pariaka and Te Maire respectively. In the Whanganui catchments, the impact of farmland and native forest on river discharge was compared and farmland in the Ongarue catchment reduced flow much more than the native forest in the upper Whanganui catchment. The relationship of the high flow (Q90) in the two catchments is quite close to the ratio relationship of the catchment area, however, the relation of the low flows in the two catchments is fairly different and exceeds much more than the 0.75 ratio relationship of the catchment area.

text: Detecting signals of climatic shifts and land use change from precipitation and river discharge variations: The Whanganui and Waikato catchments The Whanganui and Waikato river catchments have somewhat different degrees of exposure to the westerly wind systems. It is of interest to determine whether the two regions have similar times of occurrence of any concurrent shifts in river discharge and rainfall, with particular reference to mean value changes. Concurrent rainfall and runoff shifts are indicative of climatic variation but catchment land use changes (which will influence only discharge change) have also been occurring in both catchments, particularly with respect to forest planting or forest clearance. This thesis gives a summary of both climatic and land use change effects within the two catchments. If it happens that both catchments have similar climatic change-points then the data can be combined to provide a more robust framework for future water right specifications in both regions. Also, any similar responses to land use change may enable some degree of anticipation as to how future land use changes might lead to similar discharge responses.        
     
Change-points in river and rainfall time series flows were determined by an objective approach to detect breaks of slope in cumulative mass plots. Using repeated least squares fitting of piecewise linear segments, time points of maximum difference are determined as measured by the minimum least-squares in 2-segment fitting. Randomisation of time ordering of the original data was then employed to check that changes in the cumulative plots were statistically significant. Many significant but minor shifts were detected but a number of the shifts shown evidently in the rainfall and runoff cumulative mass plots. A set of change-points due to land management impacts were identified as discharge changes in the absence of concurrent rainfall changes. Rainfall-runoff linear relationship changes associate with changes in discharge time series.       

Change-points in rainfall and runoff times were detected at 44 flow gauges and 59 rainfall sites. There is some indication of a degree of natural geographic grouping with spatial correlation of times of discharge change. The times of the detected changes tend to cluster, with similar times for the same sign of change toward either greater or lower values of rainfall and discharge. The alternation of positive and negative signs is interesting as it was found 1981 and 1998 were times of negative shifts, while 1988 and 1994/1995 were times of positive shifts. Almost over the whole Waikato and Whanganui region, the changes in rainfall and runoff  appears to relate to El Nino and La Nino events, which is of practical interest for water right considerations. The driver of the shifts in rainfall pattern was found to be the changes in high rainfall events, which can change the rainfall-runoff linear relationship in some areas.             

The land use component of some of the shifts was evaluated also and found only in 10 of the 44 flow gauges. The type of the land-use can be categorized into three groups: hydropower diversion, flood control system and afforestation. Within the study catchments, the impact of hydropower diversion is more significant than the other two types. With regards to the Whanganui catchments, the operation of the Tongariro power scheme from 1973 decreased low-flow by 89% in the Wahkapapa River and around 42% and 26% of the flow in the Whanganui River at Pariaka and Te Maire respectively. In the Whanganui catchments, the impact of farmland and native forest on river discharge was compared and farmland in the Ongarue catchment reduced flow much more than the native forest in the upper Whanganui catchment. The relationship of the high flow (Q90) in the two catchments is quite close to the ratio relationship of the catchment area, however, the relation of the low flows in the two catchments is fairly different and exceeds much more than the 0.75 ratio relationship of the catchment area.

year: 2012

title: PISA, global reference societies, and policy borrowing: The promises and pitfalls of ‘academic resilience’

authors: Volante, Louis

abstract: The Programme in International Student Assessment (PISA) has become the prominent method of international comparison of the achievement of 15-year-old children in reading, mathematics, and science. Recently, the OECD, which administers PISA, has devoted a great deal of energy promoting the notion of “academic resilience”—which refers to the capacity of individuals to prosper despite encountering adverse circumstances. Countries are compared and contrasted in relation to the relative share of disadvantaged students that are able to achieve at higher achievement levels on PISA, with associations drawn from school-level factors and resulting implications drawn for policy reform. This paper offers a number of cautions with the growing influence of cross-national comparisons of academic resilience. Our discussion underscores how the OECD’s notion of “academic resilience,” which has come to dominate transnational policy debates, is quite narrow and limited by the measures it uses to assess student competencies.

text: PISA, global reference societies, and policy borrowing: The promises and pitfalls of ‘academic resilience’ The Programme in International Student Assessment (PISA) has become the prominent method of international comparison of the achievement of 15-year-old children in reading, mathematics, and science. Recently, the OECD, which administers PISA, has devoted a great deal of energy promoting the notion of “academic resilience”—which refers to the capacity of individuals to prosper despite encountering adverse circumstances. Countries are compared and contrasted in relation to the relative share of disadvantaged students that are able to achieve at higher achievement levels on PISA, with associations drawn from school-level factors and resulting implications drawn for policy reform. This paper offers a number of cautions with the growing influence of cross-national comparisons of academic resilience. Our discussion underscores how the OECD’s notion of “academic resilience,” which has come to dominate transnational policy debates, is quite narrow and limited by the measures it uses to assess student competencies.

year: 2022

title: Introduction and dedication to Matiu Dickson

authors: Te Aho, Linda

subjects: Dickson, Matiu

abstract: This edition of the Waikato Law Review is dedicated to our dear friend and colleague, Matiu Dickson, and we thank Judge Craig Coxhead for his wonderful tribute to Matiu. The morning of the 7th of April 2016 will forever be imprinted in our minds and hearts. Matiu passed away that morning having just delivered the final speech in the opening ceremony for our new Law Building here at Waikato University. It was said at his tangi that this was a high price to be paid for such a building. A price that we would never have chosen to pay. That price brings an obligation to honour and respect the legacy that Matiu has left us, his commitment to the Faculty’s founding goals and, in particular, the promotion of a bicultural legal education for Māori and non-Māori alike; that tikanga is recognised as the first law of Aotearoa New Zealand and continues to form a central part of our curriculum. Matiu personified the bicultural mission of Te Piringa Faculty of Law; that, through its curriculum, research activities and its structures, the Faculty would be the forefront of the development of a bicultural legal philosophy. Matiu worked hard to ensure this mission remained a stated goal of the Faculty and to give it meaning over his 20 year tenure. He constantly worked to infuse it into the structures and processes of this Law Faculty. He worked and campaigned for years, and successfully so, to make sure the name gifted to the Faculty by Dame Te Atairangikaahu at its founding, “Te Piringa”, became our Faculty’s officially recognised name. He was passionate about the use of te reo Māori in assessment. He encouraged and facilitated the use of te reo Māori mooting. It was our colleague, Ani Mikaere, who, during her time here as a legal academic, first publicly articulated tikanga Māori as the first law of Aotearoa. Through the years, Matiu and our academic colleagues, including Stephanie Milroy, Craig Coxhead, Caren Fox (all now Māori Land Court judges), Leah Whiu, Harata Paterson, Nan Seuffert, Ruth Bush, Wayne Rumbles, Robert Joseph, Valmaine Toki and ourselves, reaffirmed tikanga as the first law of Aotearoa in our teaching and research. Years later, the article “Lex Aotearoa: An Heroic Attempt to Map the Māori Dimension in Modern New Zealand Law” by Justice Joseph Williams2 developed the idea further and is currently the leading piece on the weaving of tikanga and Anglo-New Zealand law.3 Matiu Dickson was an expert in tikanga, the first law of Aotearoa. He lived it every day. He created and taught courses on it and made sure it was integrated throughout the curriculum. In Matiu’s honour, it is entirely appropriate that there are a number of contributions in this Review that have a Māori or Indigenous theme, and we hope future issues will likewise assure such a balance.

text: Introduction and dedication to Matiu Dickson This edition of the Waikato Law Review is dedicated to our dear friend and colleague, Matiu Dickson, and we thank Judge Craig Coxhead for his wonderful tribute to Matiu. The morning of the 7th of April 2016 will forever be imprinted in our minds and hearts. Matiu passed away that morning having just delivered the final speech in the opening ceremony for our new Law Building here at Waikato University. It was said at his tangi that this was a high price to be paid for such a building. A price that we would never have chosen to pay. That price brings an obligation to honour and respect the legacy that Matiu has left us, his commitment to the Faculty’s founding goals and, in particular, the promotion of a bicultural legal education for Māori and non-Māori alike; that tikanga is recognised as the first law of Aotearoa New Zealand and continues to form a central part of our curriculum. Matiu personified the bicultural mission of Te Piringa Faculty of Law; that, through its curriculum, research activities and its structures, the Faculty would be the forefront of the development of a bicultural legal philosophy. Matiu worked hard to ensure this mission remained a stated goal of the Faculty and to give it meaning over his 20 year tenure. He constantly worked to infuse it into the structures and processes of this Law Faculty. He worked and campaigned for years, and successfully so, to make sure the name gifted to the Faculty by Dame Te Atairangikaahu at its founding, “Te Piringa”, became our Faculty’s officially recognised name. He was passionate about the use of te reo Māori in assessment. He encouraged and facilitated the use of te reo Māori mooting. It was our colleague, Ani Mikaere, who, during her time here as a legal academic, first publicly articulated tikanga Māori as the first law of Aotearoa. Through the years, Matiu and our academic colleagues, including Stephanie Milroy, Craig Coxhead, Caren Fox (all now Māori Land Court judges), Leah Whiu, Harata Paterson, Nan Seuffert, Ruth Bush, Wayne Rumbles, Robert Joseph, Valmaine Toki and ourselves, reaffirmed tikanga as the first law of Aotearoa in our teaching and research. Years later, the article “Lex Aotearoa: An Heroic Attempt to Map the Māori Dimension in Modern New Zealand Law” by Justice Joseph Williams2 developed the idea further and is currently the leading piece on the weaving of tikanga and Anglo-New Zealand law.3 Matiu Dickson was an expert in tikanga, the first law of Aotearoa. He lived it every day. He created and taught courses on it and made sure it was integrated throughout the curriculum. In Matiu’s honour, it is entirely appropriate that there are a number of contributions in this Review that have a Māori or Indigenous theme, and we hope future issues will likewise assure such a balance.

year: 2016