INFOMAR 2013 - CELTIC VOYAGER MAPPING SOUTHERN PRIORITY AREAS AND BAYS

INFOMAR Survey CV13_01

Monday 22^nd April saw the commencement of the first RV Celtic Voyager INFOMAR survey leg of 2013, named CV13_01. Operations commenced off the Cork coast between Ballycotton and Youghal, shoreward of coverage attained in previous years.  The area forms part of the South Priority Area (SPA), stretching from Mizen Head in the south-west to Carnsore Point in the north-east.  The Priority Bays of Youghal and Dungarvan were also partially surveyed. Figure 1 shows the extent of multibeam coverage achieved in the area while figures 2, 3 and 4 show detailed seabed morphologies of the bays of Ballycotton, Dungarvan and Youghal respectively.   

Figure 1: Multibeam inshore survey coverage between Ballycotton and Dungarvan.

 

Figure 2: Seabed geomorphology offshore Ballycotton.

 

 Figure 3: Seabed geomorphology offshore Dungarvan.

 

Figure 4: Seabed geomorphology offshore Youghal.

Survey operations alternated between the inshore area above and an offshore block south of Waterford, shown in figure 5. The offshore survey block covers an area of approximately 320 km². Water depths range from 50 m to 80 m approximately with depths increasing from north to south. The seabed is mostly covered by sediment but outcropping rocks are also found in the north.

Figure 5: Offshore survey block south of Waterford.

An area east of Wexford and west of the Blackwater Bank was also mapped during a period of strong westerly winds. The multibeam shaded relief image in figure 6 shows that the seabed is largely composed of sediment waves. Water depths vary from 10 to 25 m approximately.

Figure 6: Multibeam image near Blackwater Bank Wexford.

Survey operations moved west for the final week of survey. The area included the waters around Old Head of Kinsale and Courtmacsherry Bay (figure 7). Its offshore extent was along the SPA boundary, more than 12 km offshore of the Old Head of Kinsale. Water depths ranged from 12 m to 100 m approximately. The extent of the mapped area was approximately 400 km². Several magnetic anomalies were observed, attributed to the geology. Survey operations finished on 31^st May. The Celtic Voyager remained operational for over 70% of the total time.

Figure 7: Multibeam image of Courtmacsherry Bay and Offshore Kinsale.

Wrecks

A total of 21 wrecks were mapped during this leg. Figure 8 shows an image of a wreck off the Waterford coast. The wrecks were initially identified from the main survey lines and then mapped in detail using a standard box in process of three parallel lines and one perpendicular line with multibeam water column data and magnetometer data acquired on each line.

 

Figure 8: Multibeam image of mapped wreck.

Groundtruthing stations

In total 128 groundtruthing stations were visited. A total of 111 samples were acquired from these stations, with no returns at 17. A Shipek grab was used throughout. Each sample was photographed and described. Samples varied from mud through to gravel. Figure 9 shows a photograph of the sample obtained at station 4.

Figure 9: Shipek Grab sample photograph.

Figure 10 is a distribution plot of the visited groundtruthing stations. Each red X marks a station.

Figure 10: Groundtruthing spatial distribution plot.

Sub Bottom Profiler Data

Sub bottom profiler data was acquired on each survey line. Figure 11 below shows an example of sub bottom profiler data with a palaeochannel in the view. Each horizontal red line represents 8 metres depth. The vertical blue lines are approximately 120 metres apart. The horizontal line near the top of the image represents the seabed return.

Figure 11: Sub-Bottom-Profiler data example.

 

 

 

View new data on Infomar Image Webmapping Site

New data is now available on the Infomar Image Webmapping site and in the INFOMAR webmapping services from the following surveys:

Geo11_01 - Dun Laoghaire, Co. Dublin
KRY11_01 -  Waterford Harbour
Geo11_02 - Waterford Harbour
KRY12_02 – Bunmahon, Co. Waterford
CV11_MeshAtlantic - Kenmare Bay,  Kerry/Cork
CV12_SEAI_Clare - West of Clare
KRY11_03 -  Killard Point, Co. Clare
KRY11_03 – South of Achill Island, Co. Mayo
Geo11_04 - South of Achill Island, Co. Mayo

These are primarily near shore surveys and the location of these new surveys is shown in yellow in the map.

These surveys were carried out by the R.V. Keary, the R.V. Geo and the R.V. Celtic Voyager.  Data produced from these surveys include bathymetry grids, shaded relief and a backscatter images, tracklines and survey polygons.

This image shows bathymetry data from survey around Inishbofin, Inishshark and south of Achill Island.

This is a shaded relief image of bathymetry data collected in Kenmare Bay.

The survey of Kenmare Bay was carried out by the Mesh Atlantic project with support from the INFOMAR project in terms of personnel and equipment. The Mesh Atlantic partnership is compromised of IFREMER, IMA, DIREN Bretagne (France), Marine Institute (Ireland), AZTI, IEO (Spain), ICNB, INRB, Universities of Aveiro, Azores, Algarve (Portugal).

In addition there is also new data on the website for sediment samples.  This includes historical samples in Zone 3 and particle size analysis results for sediment samples taken in 2011 and 2012.

Please note:

• All of the image layers on this website are also available as WMS services which can be used in ESRI ArcGIS Desktop, ArcGIS Explorer online and other freely available mapping packages, see the Google kml and WMS Links page for details.

• It is possible to download data used in the site. Use the   button in the tool bar at the top right of the page to click and drag a box around an area of interest, the tool will open our IWDDS download site and you then select the type of data you are interested in downloading.

Please note also to improve performance some of these layers are cached locally onto your computer as you browse the website.  In order to see new data it is necessary to clear the local cache and reload the page.  To do this in:

• Internet Explorer: click Tools > Delete Browsing History >Check Temporary Internet Files and click Delete.

• Mozilla Firefox: click Tools > Clear Recent History > Check Cache and click Clear Now

• Google Chrome: in the Chrome menu select Tools > Clear browsing data > Check Cache and click Clear Browsing data 

Lambay Island Survey

From late April to May 2013, the M.V. Cosantóir Bradán and R.V. Geo carried out survey operations around Lambay Island and along the coast between Howth and Skerries, Co. Dublin. This seabed mapping was carried out on behalf of the National Parks and Wildlife Service (NPWS - http://www.npws.ie/), who requested the survey so they could delineate habitats in the area. Survey coverage was also extended beyond the NPWS requirements in order to expand INFOMAR national mapping coverage in the area.

 

The M.V. Cosantóir Bradán is the latest addition to the INFOMAR survey fleet and is operated by the Geological Survey of Ireland (GSI). A fisheries patrol vessel in a previous life, she is now outfitted with a multibeam sonar mapping system - http://www.fisheriesireland.ie/Press-releases/minister-commissions-an-cosantoir-bradan-in-her-new-role-as-a-seabed-survey-vessel-at-infomars-2012-annual-conference.html.
The transducers (these are the part of the system that send and receive the sonar pulses) are deployed by means of a bow-mounted hydraulic frame.

 

The R.V. Geo is also operated by the GSI and is a 7.5m RIB (Rigid Inflatable Boat). She is equipped with an interferometric sonar mapping system, which is manually deployed by means of a bow-mounted frame.

Note: data shown in images below is not yet finalised and may contain some errors.

Overall survey coverage by M.V. Cosantóir Bradán and R.V. Geo

Close-up of survey coverage around Lambay Island

M.V. Cosantóir Bradán (Crosshaven, 2012)

 

 

R.V. Geo (Killary Harbour, 2012)

 

 

 

Cork Harbour Survey - To Be Updated

INFOMAR SEAI SURVEY 2013

From mid-March through to the end of April, the R.V. Celtic Voyager was tasked with the mapping of the seabed off the West Clare coast.

Due to the ideal wave regime, favourable seabed morphology and proximal port facilities, this area has been identified as a suitable region for the future deployment of wave energy converters. Sustainable Energy Authority Ireland (SEAI) leads a project to help realise this potential.

The INFOMAR program is collaborating with SEAI to provide them with a detailed understanding of the seabed morphology and surficial geology over this extensive area. Considerations of these environmental factors are critical to the planning and development of such marine infrastructure.

Despite challenging conditions for the vessel’s crew and survey team due to prolonged adverse weather, good coverage was achieved close to the coast.

The image below shows the extent of the multibeam and geophysical data collected by INFOMAR in support of the SEAI initiative.



The acquired multibeam data show some spectacular structures in the siliclastic bedrock and a Namurian/ Carboniferous contact.

KRY12_03 / GEO12_02 - Inishbofin, Inishturk & Killary Harbour

In July and August 2012, the RV Keary and RV Geo spent several weeks mapping the seabed around Inishbofin, Inishturk and Killary Harbour. The vessels were based in Inishbofin harbour for the duration of the survey.

Initially, two specific sites were mapped for BIM (Bord Iascaigh Mhara) who are investigating the potential of deep-water aquaculture sites in the area. In addition, a larger area around the islands was mapped to provide bathymetric data for oceanographic current modelling to be carried out by the Marine Institute, along with extending INFOMAR coverage into the area around the islands.

The survey data revealed very interesting underwater topography, containing extensive rocky outcrop, fault lines and sedimentary features.

Below are images of the survey coverage and the vessels at work. Note that the colour scales may vary between the survey coverage images - the red and blue ends of the spectrum represent shallower and deeper water, respectively.

Survey coverage by RV Keary and RV Geo around Inishbofin and Inishturk. The RV Geo carried out the shallower water mapping along the coastlines. Data in this image is still in the process of being finalised and contains some errors.

The "Stags" rocks off the NW coast of Inishbofin.

A view of Inishturk's rugged coastline from the RV Geo.

RV Keary.

A backscatter map of the seabed around Inishbofin and Inishturk, merged with a shaded relief map. Backscatter maps are produced from the strength of the sound waves returning to the multibeam sonar, having reflected off the seafloor - this provides information on seafloor hardness, which is then represented in greyscale here (darker shades represent harder seabed). The grey polygon in the centre and eastern part of the map represents the extent of seabed previously mapped by the RV Celtic Explorer.

Folded rock strata on Inishturk's coastline. The onshore geology on both islands is complex and ancient - the seabed mapping carried out during the survey should help to extend the understanding of it into the offshore environment.

RV Keary transiting from Inishbofin to Cleggan.

RV Keary tied up alongside Inishbofin's ferry, the Island Discovery, in Inishbofin harbour.

Structural geology of Inishturk, with seabed coverage by RV Keary and RV Geo around the island. Onshore, faults are shown in black and the synclinal axes of folded strata are shown in red. The fault marked with the red arrow appears to extend offshore in a south-easterly direction as a discontinuity in the seabed rock outcrop.

Along with successfully acquiring bathymetric data, the INFOMAR vessels completed inshore mapping around Inishbofin and Inishturk - the data will be freely available in several formats on the INFOMAR website in the future.

KRY12_02 Bunmahon

Between the 13th and 18th June 2012, the RV Keary carried out seabed mapping off the coast of Bunmahon, Co. Waterford. This survey was conducted in support of the INTERREG funded Atlanterra Project, which has designated the Bunmahon area as a Geo-park. Learn more about Atlanterra at http://www.gsi.ie/Programmes/Heritage+and+Planning/Heritage/Atlanterra.htm.

During the survey work the Keary was based in the port of Dunmore East, from which the vessel could transit to the survey area. Existing bathymetric data lay to the south, having been collected by the RV Celtic Voyager in 2007, and it was ensured that the RV Keary's coverage overlapped with that to provide quality control on the data.

Two uncharted shoals were mapped during the course of the survey, with this information then delivered to the UK Hydrographic Office (UKHO) in the form of H-notes. The UKHO will then issue a Notice to Mariners, alerting them to these hazards and will include the shoals in New Editions of charts.

Examples of the data collected are below:

Seabed data collected off Bunmahon shown as shaded relief

Backscatter image of the seabed off Bunmahon. The RV Keary uses a multibeam sonar to map the seabed - when the sound waves it produces reflect back off the seabed, the strength of the return provides information on the hardness of the seafloor material. This greyscale map was produced using that data. Note also that this image shows the data collected by the Celtic Voyager to the south.

Shoal discovered during survey operations - originally charted at 14m depth (LAT) but now found to be at 7.5m depth (LAT). The top half of the image shows it in plan view, while the lower half is a profile view. LAT = Lowest Astronomical Tide.