Legislative History: An Act Relating to Confidentiality of Records and the Prevention of Child Sexual Abuse (HP942)(LD 1331)

https://digitalmaine.com/legishist117/2330/thumbnail.jp

WHARVES AT THE EDGE OF THE WORLD: PHYSICAL MODELLING OF ZERO MAINTENANCE BREAKWATERS IN REMOTE LOCATIONS

During the design process for a breakwater, construction and maintenance considerations usually play a major part in determining the final geometry of the structure. This is particularly the case in remote locations with limited availability of materials, plant and machinery combined with the tyranny of distance. This paper presents the design development to upgrade existing wharves at two sites within, the Chatham Islands archipelago. These islands are populated by only 600 people, and the wharves on the two inhabited islands, Chatham and Pitt, provide a lifeline for their communities.The physical modelling of both wharves led to a significant reduction of design risks, and constructability improvements. Empirical techniques were found to have mixed results for estimating the stability of concrete primary armour (Xbloc® and Hanbar units) and rock toe armour. Secondary armour stability tests with the breakwater in an “under construction” state also provided insights for construction planning. On Pitt Island, wave overtopping processes were very three dimensional such that they could only be robustly estimated using the physical model. On the head of both wharves, it was necessary to extend the crown wall normal to the long axis of the breakwater to improve overtopping and armour stability on the leeward side

Australasian Coasts and Ports 2017 Conference

© Australasian Coasts and Ports 2017 Conference. All rights reserved. Management of coastal erosion caused by both natural and anthropogenic drivers is an ongoing challenge for many island nations of the Pacific. While conventional coastal protection techniques have included rock or concrete revetments and seawalls, non-conventional or 'non-engineered' protection methods have also been trialled with varying levels of success. Typically these alternative protection methods have looked to overcome obstacles to traditional forms of coastal protection such as a lack of suitable construction materials or high costs to import materials. The Pacific Region Infrastructure Facility is undertaking a study on affordable coastal protection options in the Pacific Islands. The first of three project stages developed a desktop analysis to catalogue and critically evaluate the range of coastal protection methods used throughout the Pacific Islands, and identified several more affordable alternative coastal protection methods with potential for use on low energy coastlines. These alternative methods included the use of smaller hand-placed sand-filled geotextile containers, as well as the use of concrete masonry "besser" construction blocks, both placed on a sloping revetment. These innovative protection options have the benefit of being either widely available or cheaper to import to Pacific Islands, and they can be placed without the need for heavy construction equipment. The second stage of the project comprised a physical modelling study to investigate the performance of these alternative coastal protection methods, and to develop a design guidance report. The results will be piloted in stage three to verify and monitor these alternative coastal protection measures in Pacific Islands over time. This paper presents results from the physical modelling stage of the project. The modelling program considered the stability and runup/overtopping characteristics of both 40kg sand-filled geotextile containers as well as concrete masonry blocks, placed on a 1V:1.5H revetment slope. A range of placement configurations and wave conditions were investigated for both armouring options to determine the threshold of unit stability. The results indicated that the geotextile containers could be used in wave conditions with significant wave height up to approximately 0.5 m, while the concrete masonry blocks were stable in waves with significant wave height up to 1 m

CROSS-SHORE SANDBARS RESPONSE TO AN ARTIFICIAL REEF: AN INTERSITE COMPARISON

International audienceWhile a clear improvement concerning aesthetic considerations using soft submerged breakwater is undeniable, their design has often focused on wave energy decrease in their lee, overlooking their impact on the dynamics of the nearby nearshore sandbar(s). At the beach of Sète (southeast France), the submerged structure clearly affects the natural net offshore migration cycle (NOM) of the former double barred beach. On the contrary, at Narrowneck (Queensland, Australia), the deployment of a multi-functional submerged structure does not affect the cross-shore sandbar processes. These contrasting behaviors are addressed using high frequency video monitoring. After discussing observations at both field sites, a process-based morphodynamic model provides insight into the morphological sandbars response to artificial reefs