

@mastersthesis {6446,
	title = {An investigation into sandy beach stabilisation through controlled drainage},
	year = {2001},
	note = {C808189},
	school = {University of Southampton (United Kingdom)},
	type = {phdPh.{D}.},
	address = {Ann Arbor},
	abstract = {Previous studies have demonstrated the potential for improving beach stability through controlled drainage. However, the results of full scale trials are varied, and the application of the technique has been hindered by a shortage of practical information on the performance of beach drainage systems in conditions relevant to the UK shoreline. This report describes an investigation into the mechanisms of beach drainage and the factors affecting system performance. A beach drainage model was developed using a 1:20 linear scale and Bakelite sediment. Test results support the theories that beach stabilisation through drainage occurs due to surge volume reduction (leading to laminar flow phase extension) and pore water pressure reduction (resulting in reduced liquefaction in the swash zone). The results also show that drainage system effectiveness is proportional to discharge. Data support the theory that for non-tidal conditions and a monochromatic wave climate, the optimum performance occurs when the upper part of the swash is located over the zone of maximum influence of the drain. Scaling considerations suggest that in terms of the magnitude of beach volume change the model results are an overestimate, although qualitatively the results are likely to apply to the field. As part of the study, a field trial was carried out at Branksome Chine, Dorset. This report describes the installation and first 6 months of operation during which time the system yield, local weather patterns and beach levels were recorded. Field observations and survey data show that the drainage system successfully stabilised the beach at Branksome Chine during the first two months of the trial. However, spring tides and storms caused sufficient damage to render the system inoperative during a crucial period of further storms enabling erosion to occur. The system was reinstated soon afterwards, but with a considerably reduced yield, and the effect of the repaired system was limited. The trial demonstrated that beach drainage can be an effective stabilisation option, but robust design, prompt maintenance and high yield are vital to its success. Model experiments show that during prolonged storms, some beach material loss is inevitable, and the stabilisation effect of the drainage system is not instantaneous. However, provided the system remains in operation beach levels will begin to recover and accretion will occur during otherwise erosive conditions. Alternative drainage system designs comprising geo-composite permeable layers and a shore normal collector pipe have been proposed. Preliminary experiments demonstrate that geo-composite beach drainage may be a feasible method of shoreline stabilisation, however further study is recommended.},
	keywords = {0543:Civil engineering, 0775:Environmental engineering, Applied sciences, Civil engineering, Drainage, Environmental engineering, Sandy beach, Shoreline stabilization},
	url = {http://search.proquest.com/docview/304777217?accountid=14270},
	author = {Mulvaney, Heidi Sarah}
}
