KRY10_03 Clifden and Mannin Bay

On completion of the survey portion of work in Kinsale, the RV Keary made the transit to Clifden Bay to begin mapping in Clifden Bay, Mannin Bay and the seabed outside the bays, north of Slyne Head to Cruagh Island. The inner most and shallowest areas of the bays had been surveyed using LiDAR earlier in the year. Click here for more information on that LiDAR survey.

Overview image of multibeam sonar data of all coverage achieved in Clifden and Mannin Bays. LiDAR coverage is represented by the hatched area.

Initially the survey was concentrated in the deeper water areas, seaward of the bays. It was in this area, NE of the Barret Shoals that a steep outcrop of rock rising to a chart depth of 12.2 metres in surrounding water depths of 30 to 40 metres was mapped for the first time. This significant shoal was surveyed in detail and a H102 note was prepared for the United Kingdom Hydrographic Office (UKHO) so that this shoal location can be quickly updated in the charts as a possible danger to navigation.

Datasets showing the previously uncharted shoal mapped during INFOMAR survey KRY10_03, NE of the Barret Shoals.

Multibeam sonar data showing three charted shoals mapped west of Clifden Bay during INFOMAR survey KRY10_03. The data shows that water depths are shallower (shown as red and orange colours) over these rock outcrops than the surrounding seabed (shown as green and blue colours) and can present a danger to navigation.

Entrance to Clifden Bay with the beacon on Errislanan marking the southern entrance of the bay. In the background are the Twelve Pins mountains of Connemara. The ruins of Clifden castle can also be seen in the centre of the photograph. The RV Keary anchored in Clifden Bay during the survey of Clifden and Mannin Bay.

All INFOMAR data is available for free download here.

2010 LiDAR Surveying

From the 1st March to 17th March, INFOMAR contracted Pelydryn to perform airborne Light Detection and Ranging (LiDAR) surveys in a series of shallow water bays and loughs on the West, Northwest and North coasts. This geophysical method involves the use of eye-safe laser technology to measure water depths. It is achieved by calculating the difference between laser returns from the sea surface and the seabed.

Based at Knock and Donegal airports, Pelydryn surveyed parts of Broadhaven Bay, Blacksod Bay and Achill Sound in the Northwest. Lough Foyle, Lough Swilly and Mulroy Bay in the North. Clifden Bay, Mannin Bay, Ballyconneely Bay, Bertraboy Bay and Kilkeran Bay were surveyed in Co. Galway. Datasets collected include both marine and terrestrial LiDAR as well as aerial photographs to facilitate seamless integration of both offshore LiDAR and acoustic datasets to onshore topographic surveys.

The aircraft used by Pelydryn during the LiDAR surveys taking off from Ireland West Airport Knock. The plane was grounded on several occasions during the survey period due to volcanic ash from the Eyjafjallajokull volcano in Iceland. Nevertheless, the survey was still successful in gathering a large amount of data in areas where acoustic surveying on a boat would be time consuming and have an increased risk attached.

Coverage of LiDAR surveys in Broadhaven Bay, Blacksod Bay, Achill Sound. Previous INFOMAR survey areas shown in hatched areas.

Coverage of LiDAR surveys in Clifden Bay, Mannin Bay, Ballyconneely Bay, Bertraboy Bay and Kilkeran Bay. Previous INFOMAR survey areas shown in hatched areas.

Coverage of LiDAR surveys in Lough Foyle, Lough Swilly and Mulroy Bay. Previous INFOMAR survey areas shown in hatched areas. The outer reaches of Mulroy Bay have also been previously surveyed using LiDAR.

All INFOMAR data is available for free download here.