Complex considerations for Maltese breakwater project
The wave climate in the vicinity of Marsaxlokk Bay sets design parameters which must address protection for the fishing village whilst mitigating against fairway infilling
Malta, explains Nigel West of ABPMer, has an enormous strategic importance for the marine industry, and consequently an equally large maritime built environment. This in itself generates a background complexity for marine structures in the area, and Marsaxlokk fishing village is no exception.
Working for Colin Toms & Partners, ABPMer has finished its testing programme of the proposed breakwaters in the vicinity of the village which resides at the rear of Marsaxlokk Bay.
Mr West explained that, although the bay affords some natural protection from the sea, occasional offshore swells still penetrate directly through the embayment to affect the fishing village. An existing breakwater had suffered significant storm damage and there was some debate as to its further role. ‘So our primary focus had to be reducing wave height across the area, and especially in the moorings’, he said.
Of interest is the fact that Mr West describes the local fishing cooperative, a large part of the local economy, as being particularly ‘keen’ when it came to understanding some of the more complex wave reflections and where the proposed structures should be placed. He says that the area tends toward very vertical quay walls which in turn lead to an increased amount of wave reflection. This again has a huge influence on the totality of the wave climate, something that the fishermen experience first hand.
Their needs, along with those of other users of the bay and the village inhabitants, had to be taken into account for a satisfactory conclusion. Part of the brief was to look at creating additional berthing areas outside the existing safe haven.
However, waves are not the only concern for the client. Currents generated by the waves as they enter the bay are responsible for the infilling of the fairway. It was obvious new breakwaters must not enhance this transport mechanism and rather, should be aligned to inhibit the fairway infilling.
Mr West explained, ‘Of the options that came out of the programme, there would now seem to be a number of ‘main contenders’. One of them is not just to repair the existing breakwater, but to also extend it by another 100m, giving it an overall length of 250m.’
Above and beyond this are the possibilities of creating either one or two more armoured breakwaters that will both give wave protection and help to reduce the build up of silt, although dredging is an inevitable part of the scheme.
Going forward, any new construction will have to take its chances not only with the marine environment, but also the rough and tumble of both European as well as local economics.
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