Remarkable images of Clew Bay and the approaches to Westport Harbour have emerged from a new survey by the Geological Survey of Ireland (GSI).
The images were captured by a laser system, mounted on the underside of a small aircraft, to measure the depth of water below. With the aircraft flying at a height of about 500 metres, the survey covered an area of one square kilometre a minute over a period of two days in June.
The work was carried out by an Australian company for the GSI, which is conducting a €27 million survey of the Irish seabed. The new map resulting from it updates a 106-year-old chart of the Clew Bay area. The results show that the original 1896 chart of the bay carried out by the British admiralty was produced to "an extremely high level of accuracy for its time", according to the GSI. "To date we have used ships for data acquisition as we have been concentrating on waters of greater than 200 metres in depth," Dr Peadar McArdle, director of the GSI, said. However, aircraft were more economic in terms of time and cost for mapping areas closer to the seashore, he explained. Presenting results from the survey, Mr Robert Caprile and Mr Mark Sinclair of the Tenix LADS Corporation said the clarity of the waters off the west coast made the area suitable for this kind of survey. The LADS (laser airborne depth sounding) technology is an internationally accepted survey tool that is accurate to international hydrographic surveying standards, they said. The results can be used for coastal zone and coral reef mapping and management, marine exploration, engineering and marine resource management.
Mr Michael Moran, secretary of the Westport Harbour Authority, said he was very impressed with the data.
"This survey and the chart it has delivered give us a clearer picture of the approaches to Westport Harbour and the texture of the seafloor. An accurate understanding of the seafloor is very important today with ever-increasing traffic, both commercial and leisure, entering our ports," he added.