Dublin Bay and Approaches
Cuan Bhaile Átha Cliath

• Overview
• INFOMAR Survey History
• Bathymetry
• Shaded Relief
• Backscatter
• Ground Truthing \ Seabed Sampling
• Seabed Classification
• INFOMAR in Google Earth
• Data Access

Overview

Dublin Bay is located on the east coast of Ireland. It can be defined as the area of water from Howth Head in the north to Dalkey Head in the south. It is approximately 10 kilometres across the mouth of the bay and narrows to the mouth of the River Liffey which enters the Irish Sea in Dublin Bay. A large portion of the inner bay is affected by the rise and fall of the tides, with large areas of sand and mudflats exposed at low tide.

Photographs showing the coastline of Howth Head (left) and Bray Head (right) taken during INFOMAR surveying and ground truthing of Dublin Bay and Approaches.

Within the bay, the North Bull Island is a prominent physical, man-made feature which developed due to sedimentation accumulation after the construction of the North Bull wall in 1821 to ameliorate the problem of siltation in Dublin Harbour. Along with the seawalls protecting Dublin Harbour, the pier walls at Dun Laoghaire Harbour are an impressive feature in the south of the bay. The upland areas of Howth Head, Dalkey Head with the Wicklow Mountains to the south and the Poolbeg chimney stacks dominate the sky line of Dublin Bay.

Location of Dublin Bay in Co. Dublin on the east coast of Ireland.

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INFOMAR Survey History

INFOMAR surveys of the area include both Dublin Bay and the approaches in the Irish Sea. Work to survey these areas began 2003 when the Celtic Voyager surveyed a large area outside the mouth of the bay but also a significant portion of the seabed east of Dun Laoghaire. In 2004, the Celtic Voyager again mapped an area to the north around Howth. In 2008, surveying around the area of the Kish bank commenced and coverage of a large portion of seabed to the east of the bank was achieved.

Coverage from survey legs undertaken to survey Dublin Bay and Approaches for the INFOMAR project to date. (Click image for a more detailed map)

Details of surveys undertaken in Dublin Bay and Approaches. (Click image for more detail)

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Bathymetry

A detailed chart of the bathymetry of Dublin Bay will be available once the inner part of Dublin Bay has been surveyed.

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Shaded Relief

Spectacular MBES shaded relief image of the seabed at the mouth of Dublin Bay with the Burford Bank in the centre of the bay, which was and is a significant hazard to marine traffic in the Dublin Harbour area. From a geological perspective, the sand waves at the northern and southern ends of the bank illustrate the strong tidal currents moving in the area which created and maintain this stunning seabed feature. Also visible is the Frazer Bank, south of Dalkey Island which again shows the dynamic sedimentary processes operating in the Irish Sea. (Click image for a more detailed map)

A more detailed chart of the shaded relief of Dublin Bay will be available once the inner part of Dublin Bay has been surveyed.

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Backscatter

MBES backscatter image draped on the MBES shaded relief image showing the Burford Bank and area south of Howth Head. The strong backscatter areas (dark areas) are generally representative of coarser grained sediments such as gravels and coarse sands. Interestingly, the light area of low backscatter intensity, corresponding to the Burford Bank, suggests that the bank is composed predominantly of sands with little coarse fraction present. (Click image for a more detailed map)

A more detailed chart of the backscatter of Dublin Bay will be available once the inner part of Dublin Bay has been surveyed.

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Ground Truthing/Seabed Sampling

A range of seabed sampling has been undertaken in Dublin Bay under the INFOMAR project. These include grab samples. The locations of the grab samples have been mainly determined by the seabed classification made from the multibeam data.

Seabed sampling locations from Dublin Bay where Van Veen grab and Day grab instruments were used to ground truth INFOMAR datasets. (Click image for a more detailed map)

Sediment sample recovered from the seabed off Bray Head as part of the ground truthing of the Dublin Bay seabed classification.(Click image for a more detail)

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Seabed Classification

The classification of the multibeam dataset from Dublin Bay resulted in the creation of a 5 class classification divided into two types of rock, reflecting the different textures observed from rock outcrops in the bay. Three more classes divided the sediments into Gravels and Coarse Sand, Coarse to Medium Sand and Fine Sand to Mud.

Seabed Classification Chart for an area around Dalkey Island, Co. Dublin. (Click image for a more detailed map)

Seabed Classification Chart for the East Coast (Click image for a more detailed map)

For a more detailed chart of the seabed classification of surveyed areas of the East Coast click here

Further information about the classification process can be found in the Data Processing section.

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INFOMAR in Google Earth

To view and navigate around the merged East Coast datasets in Google Earth, click here

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Data Access

Full details outlining the process to gain access to datasets for the bay above or all INFOMAR data can be found in the INFOMAR | Data page of this website.

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Return to Survey Details Map

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