title: Ebb-Jet dynamics and transient eddy formation at Tauranga Harbour: Implications for entrance channel shoaling

authors: Spiers, Kyle C.

subjects: coastal hydrodynamic modelling

abstract: In 1992 the entrance channel through the tidal inlet to Tauranga Harbour, which is located along the Bay of Plenty littoral drift system, was deepened from 10 m to 14 m. The deepened channel has become a sediment trap for littoral drift bypassing and tidal current driven sediment transport through the inlet. Since 1992, there has been an increase in maintenance dredging requirements at the inlet, because of sand accumulation along the southeastern border of the entrance channel. Previous studies have identified an ebb tide–induced eddy operating on the eastern side of the ebb-jet as it exits the tidal gorge. In this article, the eddy system has been simulated with a validated two-dimensional hydrodynamic model, detailing time-varying current patterns over the ebb-tidal delta. Particular emphasis is placed on defining the trajectory of the eddy and evaluating its influence on the observed sedimentation patterns. The model results indicate the formation of opposing eddies on either side of the entrance channel, both of which are transient in nature. The centre of the eastern eddy propagates seaward along the downdrift margin of the entrance channel as the ebb-jet lengthens. Bathymetric survey residuals between 2004 and 2006 confirm significant accumulations of sediment along this downdrift margin. The evidence is consistent that the eddy system exerts a directional control over transport of sediments entrained by waves over the ebb-tidal delta.

text: Ebb-Jet dynamics and transient eddy formation at Tauranga Harbour: Implications for entrance channel shoaling In 1992 the entrance channel through the tidal inlet to Tauranga Harbour, which is located along the Bay of Plenty littoral drift system, was deepened from 10 m to 14 m. The deepened channel has become a sediment trap for littoral drift bypassing and tidal current driven sediment transport through the inlet. Since 1992, there has been an increase in maintenance dredging requirements at the inlet, because of sand accumulation along the southeastern border of the entrance channel. Previous studies have identified an ebb tide–induced eddy operating on the eastern side of the ebb-jet as it exits the tidal gorge. In this article, the eddy system has been simulated with a validated two-dimensional hydrodynamic model, detailing time-varying current patterns over the ebb-tidal delta. Particular emphasis is placed on defining the trajectory of the eddy and evaluating its influence on the observed sedimentation patterns. The model results indicate the formation of opposing eddies on either side of the entrance channel, both of which are transient in nature. The centre of the eastern eddy propagates seaward along the downdrift margin of the entrance channel as the ebb-jet lengthens. Bathymetric survey residuals between 2004 and 2006 confirm significant accumulations of sediment along this downdrift margin. The evidence is consistent that the eddy system exerts a directional control over transport of sediments entrained by waves over the ebb-tidal delta.

year: 2009

title: Soil crusting in Western Samoa. Part I - Some examples of crusting and methods of control

authors: Reynolds, S.G.

abstract: The problems and effects of soil crusting in Western Samoa are discussed. Illustrations of typical crust features include the glazed or 'frosted' surface of certain crusts, and dispersion mosaics. Surface mulches and fine wire mesh frames were investigated as control measures to dissipate the considerable kinetic energy of falling raindrops before they reach the soil surface. Soil crusting was much reduced by these control methods. Mulching increased the germination percentage of dwarf beans, and frames the germinating percentage of lettuce and cabbage over untreated plots; the yield of dwarf beans was increased by 80 per cent using a mulch of coconut fronds.

text: Soil crusting in Western Samoa. Part I - Some examples of crusting and methods of control The problems and effects of soil crusting in Western Samoa are discussed. Illustrations of typical crust features include the glazed or 'frosted' surface of certain crusts, and dispersion mosaics. Surface mulches and fine wire mesh frames were investigated as control measures to dissipate the considerable kinetic energy of falling raindrops before they reach the soil surface. Soil crusting was much reduced by these control methods. Mulching increased the germination percentage of dwarf beans, and frames the germinating percentage of lettuce and cabbage over untreated plots; the yield of dwarf beans was increased by 80 per cent using a mulch of coconut fronds.

year: 1971

title: Māori child rearing and infant sleep practices

authors: Jones, Horiana Majorie

abstract: Sleep is important to a healthy lifestyle for parents and children, and having effective ways of putting a child to sleep contributes significantly to mental and physical wellbeing. Cultural groups around the world have developed a variety of approaches to this task, for example, rocking, co-sleeping, bed-sharing, breastfeeding to sleep, and encouraging infants to self soothe through various methods of infant sleep training. In New Zealand the continuation of traditional Māori approaches to infant sleep, e.g. co-sleeping, bed-sharing, responsivity to infant cues have been over-shadowed by its negative association with sudden infant death syndrome (SIDS) and dependence on parent interaction when initiating infant sleep. In this study, we were interested in the approaches Māori parents used to put their pēpi (child, 2 months-2 years of age) to sleep and the various factors that have influenced these approaches. Data were collected through online surveys (n =58) and face-to-face interviews (n =10) with Māori parents. Survey results indicated that being held and breast or bottle fed to sleep were the most practiced techniques by Māori parents. Parent assisted approaches, e.g., rocking, feeding, lying with baby until they go to sleep, were the most practiced. Many parents planned for their babies to sleep separately but very few actually persisted with self-soothing approaches due to a number of factors, such as discomfort with listening to their babies cry, culture, whānau (extended families) influences safety, and convenience. The majority of participants expressed a desire for separate sleep; however, few within the interview group actually successfully practiced separate sleep regularly.

text: Māori child rearing and infant sleep practices Sleep is important to a healthy lifestyle for parents and children, and having effective ways of putting a child to sleep contributes significantly to mental and physical wellbeing. Cultural groups around the world have developed a variety of approaches to this task, for example, rocking, co-sleeping, bed-sharing, breastfeeding to sleep, and encouraging infants to self soothe through various methods of infant sleep training. In New Zealand the continuation of traditional Māori approaches to infant sleep, e.g. co-sleeping, bed-sharing, responsivity to infant cues have been over-shadowed by its negative association with sudden infant death syndrome (SIDS) and dependence on parent interaction when initiating infant sleep. In this study, we were interested in the approaches Māori parents used to put their pēpi (child, 2 months-2 years of age) to sleep and the various factors that have influenced these approaches. Data were collected through online surveys (n =58) and face-to-face interviews (n =10) with Māori parents. Survey results indicated that being held and breast or bottle fed to sleep were the most practiced techniques by Māori parents. Parent assisted approaches, e.g., rocking, feeding, lying with baby until they go to sleep, were the most practiced. Many parents planned for their babies to sleep separately but very few actually persisted with self-soothing approaches due to a number of factors, such as discomfort with listening to their babies cry, culture, whānau (extended families) influences safety, and convenience. The majority of participants expressed a desire for separate sleep; however, few within the interview group actually successfully practiced separate sleep regularly.

year: 2017