title: The use of video imagery to analyse groundwater and shoreline dynamics on a dissipative beach

authors: Huisman, Christien E.

subjects: beach groundwater

abstract: Groundwater seepage is known to influence beach erosion and accretion processes. However, field measurements of the variation of the groundwater seepage line (GWSL) and the vertical elevation difference between the GWSL and the shoreline are limited. We developed a methodology to extract the temporal variability of the shoreline and the wet-dry boundary using video imagery, with the overarching aim to examine elevation differences between the wet-dry boundary and the shoreline position in relation to rainfall and wave characteristics, during a tidal cycle. The wet-dry boundary was detected from 10-minute time-averaged images collected at Ngaranui Beach, Raglan, New Zealand. An algorithm discriminated between the dry and wet cells using a threshold related to the maximum of the red, green and blue intensities in Hue-Saturation-Value. Field measurements showed this corresponded to the location where the watertable was within 2 cm of the beachface surface. Timestacks, time series of pixels extracted from cross-shore transects in the video imagery, were used to determine the location of the shoreline by manually digitizing the maximum run-up and minimum run-down location for each swash cycle, and averaging the result. In our test data set of 14 days covering a range of wave and rainfall conditions, we found 6 days when the elevation difference between the wet-dry boundary and the shoreline remained approximately constant during the tidal cycle. For these days, the wet-dry boundary corresponded to the upper limit of the swash zone. On the other 8 days, the wet-dry boundary and the shoreline decoupled with falling tide, leading to elevation differences of up to 2.5 m at low tide. Elevation differences between the GWSL and the shoreline at low-tide were particularly large when the cumulative rainfall in the preceding month was greater than 200 mm. This research shows that the wet-dry boundary (such as often used in video shoreline-finding algorithms) is related to groundwater seepage on low-sloped, medium to fine sand beaches such as Ngaranui Beach (mean grain size~0.27 mm, beach slope ~1:70) and may not be a good indicator of the position of the shoreline.

text: The use of video imagery to analyse groundwater and shoreline dynamics on a dissipative beach Groundwater seepage is known to influence beach erosion and accretion processes. However, field measurements of the variation of the groundwater seepage line (GWSL) and the vertical elevation difference between the GWSL and the shoreline are limited. We developed a methodology to extract the temporal variability of the shoreline and the wet-dry boundary using video imagery, with the overarching aim to examine elevation differences between the wet-dry boundary and the shoreline position in relation to rainfall and wave characteristics, during a tidal cycle. The wet-dry boundary was detected from 10-minute time-averaged images collected at Ngaranui Beach, Raglan, New Zealand. An algorithm discriminated between the dry and wet cells using a threshold related to the maximum of the red, green and blue intensities in Hue-Saturation-Value. Field measurements showed this corresponded to the location where the watertable was within 2 cm of the beachface surface. Timestacks, time series of pixels extracted from cross-shore transects in the video imagery, were used to determine the location of the shoreline by manually digitizing the maximum run-up and minimum run-down location for each swash cycle, and averaging the result. In our test data set of 14 days covering a range of wave and rainfall conditions, we found 6 days when the elevation difference between the wet-dry boundary and the shoreline remained approximately constant during the tidal cycle. For these days, the wet-dry boundary corresponded to the upper limit of the swash zone. On the other 8 days, the wet-dry boundary and the shoreline decoupled with falling tide, leading to elevation differences of up to 2.5 m at low tide. Elevation differences between the GWSL and the shoreline at low-tide were particularly large when the cumulative rainfall in the preceding month was greater than 200 mm. This research shows that the wet-dry boundary (such as often used in video shoreline-finding algorithms) is related to groundwater seepage on low-sloped, medium to fine sand beaches such as Ngaranui Beach (mean grain size~0.27 mm, beach slope ~1:70) and may not be a good indicator of the position of the shoreline.

year: 2011

title: The operation of biopower and biopolitics in the implementation process of reproductive health policies in Peru

authors: Jacay, Sheilah

abstract: In present-day societies, human life is often an arena of debate within which claims of morality, knowledge, and truth are contested. The meaning of human life, as well as the right to exert control over the bodies that create this life, are constructed by various discourses. In this process, special attention is paid to human bodies with particular capacities and needs, such as women’s bodies. The reproductive capacity of women’s bodies has long been considered central to defining the meaning of being a woman in Western societies. This gender essentialism related to the maternal role guides some reproductive health policies, which are implemented within a complex architecture of discourses, institutionalized social stratification, biopower and biopolitics. The Peruvian case offers clear examples of this situation.

In Peru, reproductive healthcare policy has been irregularly implemented throughout the last twenty years, mostly due to the strong influence that conservative Catholic groups have been able to exert on the Peruvian Government. The discourse articulated by these groups asserts that human life begins at the moment of conception and is a gift from God; therefore, no one should be permitted to interfere in the processes of human life from conception until death. This sacralisation of human life has been progressively constructed within Catholic doctrine, which today incorporates selective interpretations of scientific knowledge in support of its claims. This discourse about human life directly and adversely affects Peruvian women’s bodies and lives. Due to their reproductive capacity, the conservative Catholic discourse considers women as bearers of human life. However, their decision-making power about the creation of this life is not taken into account in this discourse, especially when this decision-making power is linked to the exertion of sexual and reproductive rights. The influence of conservative Catholic discourse on the implementation process of Peru’s reproductive health policy is thus the central focus of this thesis.
The analysis offered in this thesis is informed by a feminist critical discourse analysis of Peruvian politics, policy and law relating to three key issues: coercive sterilisation of indigenous Peruvian women during the regime of Fujimori (1996-2000), the ongoing lack of access to safe and legal abortion, and the 2009 Constitutional Court ban on the distribution of free emergency contraception within the public health sector. My analysis reveals that the Catholic interest in, and influence on, reproductive health policy was largely stimulated by Fujimori’s policy of coercive sterilization, which was in turn prompted by a eugenic discourse that conservative Catholic groups, among others within Peruvian civil society, actively denounced. This opposition consolidated the influence of conservative Catholic discourse within the political domain.  Further, I suggest that the actions of the State, increasingly influenced by Catholic interests, can best be understood in terms of Foucault’s concept of biopower, with reproductive health policy being the primary tool used to effect the State’s biopolitical agenda. As I illustrate, the influence of Catholic discourse on reproductive policy and practice is most clearly evident in the ongoing impediments placed in the way of women trying to access therapeutic abortions, and the prohibition of the free distribution of the emergency contraceptive pill via the public health system.  Even in the face of local and international condemnation, the State persists in its non-compliance with the provisions of international human rights agreements, a failure which I suggest can only be understood by acknowledging the defining influence of Catholic discourse and interests within Peru’s political domain.
The significance of this thesis thus lies in its analysis of the discourses and political machinations that restrict the exertion of Peruvian women’s sexual and reproductive rights. These constraints are achieved through the operation of biopower enacted through the implementation of various reproductive health policies. This situation, I suggest, confines women via a constructed “naturalness” that reproduces essentialist notions of gender. As the case studies presented in this thesis demonstrate, a vital component of this discursive essentialisation of the maternal role is the identification of women as reproductive bodies that can be regulated and managed in accordance with the interests and discursive affiliations of the State, as opposed to individual citizens with autonomous decision-making power over their bodies and their own lives.

text: The operation of biopower and biopolitics in the implementation process of reproductive health policies in Peru In present-day societies, human life is often an arena of debate within which claims of morality, knowledge, and truth are contested. The meaning of human life, as well as the right to exert control over the bodies that create this life, are constructed by various discourses. In this process, special attention is paid to human bodies with particular capacities and needs, such as women’s bodies. The reproductive capacity of women’s bodies has long been considered central to defining the meaning of being a woman in Western societies. This gender essentialism related to the maternal role guides some reproductive health policies, which are implemented within a complex architecture of discourses, institutionalized social stratification, biopower and biopolitics. The Peruvian case offers clear examples of this situation.

In Peru, reproductive healthcare policy has been irregularly implemented throughout the last twenty years, mostly due to the strong influence that conservative Catholic groups have been able to exert on the Peruvian Government. The discourse articulated by these groups asserts that human life begins at the moment of conception and is a gift from God; therefore, no one should be permitted to interfere in the processes of human life from conception until death. This sacralisation of human life has been progressively constructed within Catholic doctrine, which today incorporates selective interpretations of scientific knowledge in support of its claims. This discourse about human life directly and adversely affects Peruvian women’s bodies and lives. Due to their reproductive capacity, the conservative Catholic discourse considers women as bearers of human life. However, their decision-making power about the creation of this life is not taken into account in this discourse, especially when this decision-making power is linked to the exertion of sexual and reproductive rights. The influence of conservative Catholic discourse on the implementation process of Peru’s reproductive health policy is thus the central focus of this thesis.
The analysis offered in this thesis is informed by a feminist critical discourse analysis of Peruvian politics, policy and law relating to three key issues: coercive sterilisation of indigenous Peruvian women during the regime of Fujimori (1996-2000), the ongoing lack of access to safe and legal abortion, and the 2009 Constitutional Court ban on the distribution of free emergency contraception within the public health sector. My analysis reveals that the Catholic interest in, and influence on, reproductive health policy was largely stimulated by Fujimori’s policy of coercive sterilization, which was in turn prompted by a eugenic discourse that conservative Catholic groups, among others within Peruvian civil society, actively denounced. This opposition consolidated the influence of conservative Catholic discourse within the political domain.  Further, I suggest that the actions of the State, increasingly influenced by Catholic interests, can best be understood in terms of Foucault’s concept of biopower, with reproductive health policy being the primary tool used to effect the State’s biopolitical agenda. As I illustrate, the influence of Catholic discourse on reproductive policy and practice is most clearly evident in the ongoing impediments placed in the way of women trying to access therapeutic abortions, and the prohibition of the free distribution of the emergency contraceptive pill via the public health system.  Even in the face of local and international condemnation, the State persists in its non-compliance with the provisions of international human rights agreements, a failure which I suggest can only be understood by acknowledging the defining influence of Catholic discourse and interests within Peru’s political domain.
The significance of this thesis thus lies in its analysis of the discourses and political machinations that restrict the exertion of Peruvian women’s sexual and reproductive rights. These constraints are achieved through the operation of biopower enacted through the implementation of various reproductive health policies. This situation, I suggest, confines women via a constructed “naturalness” that reproduces essentialist notions of gender. As the case studies presented in this thesis demonstrate, a vital component of this discursive essentialisation of the maternal role is the identification of women as reproductive bodies that can be regulated and managed in accordance with the interests and discursive affiliations of the State, as opposed to individual citizens with autonomous decision-making power over their bodies and their own lives.

year: 2012

title: The biology and general ecology of the Koaro (Galaxias brevipinnis) in some tributary streams of Lake Taupo

authors: Kusabs, Ian Andrew

abstract: The ecology and general biology of Galaxias brevipinnis were studied in three tributary streams of Lake Taupo between May 1988 and April 1989. Adult koaro were found in relatively high densities in the Waipehi and Omori streams but in low densities in the larger Waiotaka stream. The results of population estimation studies suggest that the distribution and abundance of koaro is negatively correlated with that of trout. There was a general decline in the population density of stream-resident koaro in the winter months. Juvenile koaro were found to migrate into the tributaries from August to December, with migrations being at a peak in October and November.

Population length-frequency distributions and otoliths used to age koaro indicated that there were up to 5 age classes. Growth was allometric and was adequately described by the von Bertalanffy equation after the first year of life. Koaro were found to be in best condition in the Spring and lowest in Winter.

Spawning appeared to occur from December through to April peaking in late Summer to early in the Waipehi Stream was Autumn. The mean fecundity of koaro approximately 5500. A sex-ratio of approximately 1:1 (males: females) were found in the koaro populations in the Omori and Waipehi streams, but during spawning there were always more ripe males than gravid females.

There was considerable overlap in the diets of both koaro and juvenile rainbow trout in the Waipehi and Omori streams, with invertebrates being consumed according to their relative abundance in the benthos. Ephemeroptera larvae were numerically the most important food item in the diet of both species. However, by weight, fish (juvenile koaro) were the most important food · item in the diet of koaro and rainbow trout in the Waipehi stream. In the Omori stream in Winter, trout eggs were the most important food item in terms of weight. Terrestrial prey was found to be of relatively minor importance in the diets of koaro and rainbow trout in the Waipehi and Omori streams.

text: The biology and general ecology of the Koaro (Galaxias brevipinnis) in some tributary streams of Lake Taupo The ecology and general biology of Galaxias brevipinnis were studied in three tributary streams of Lake Taupo between May 1988 and April 1989. Adult koaro were found in relatively high densities in the Waipehi and Omori streams but in low densities in the larger Waiotaka stream. The results of population estimation studies suggest that the distribution and abundance of koaro is negatively correlated with that of trout. There was a general decline in the population density of stream-resident koaro in the winter months. Juvenile koaro were found to migrate into the tributaries from August to December, with migrations being at a peak in October and November.

Population length-frequency distributions and otoliths used to age koaro indicated that there were up to 5 age classes. Growth was allometric and was adequately described by the von Bertalanffy equation after the first year of life. Koaro were found to be in best condition in the Spring and lowest in Winter.

Spawning appeared to occur from December through to April peaking in late Summer to early in the Waipehi Stream was Autumn. The mean fecundity of koaro approximately 5500. A sex-ratio of approximately 1:1 (males: females) were found in the koaro populations in the Omori and Waipehi streams, but during spawning there were always more ripe males than gravid females.

There was considerable overlap in the diets of both koaro and juvenile rainbow trout in the Waipehi and Omori streams, with invertebrates being consumed according to their relative abundance in the benthos. Ephemeroptera larvae were numerically the most important food item in the diet of both species. However, by weight, fish (juvenile koaro) were the most important food · item in the diet of koaro and rainbow trout in the Waipehi stream. In the Omori stream in Winter, trout eggs were the most important food item in terms of weight. Terrestrial prey was found to be of relatively minor importance in the diets of koaro and rainbow trout in the Waipehi and Omori streams.

year: 1989