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Dingle & Tralee Bays

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Overview

Dingle & Tralee Bays are located in Co Kerry in south-west Ireland.

Dingle Bay is about 48 km long, running in a north-easterly to south-westerly direction. The entrance to the bay is roughly 20 km wide, narrowing to 3 km at its head. To the west of the peninsula lie the Blasket Islands, a group of six main islands and several smaller ones.

Tralee Bay is situated between Kerry Head to the north, the Magharees Peninsula to the west and extends eastwards as far as the bridge at Blennerville.

Location of Dingle & Tralee Bays, Co Kerry in the south-west of Ireland.

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INFOMAR Seabed Surveys

How we map the seabed

We use a Multibeam Echosounder (MBES) on a boat. The depth is calculated based on the time it takes the sound to be emitted from the sensor, hit the seabed and bounce back. 

We also use planes (Lidar), satellites and drones  in shallow areas, unsafe for boats. 

The deeper offshore seabed areas around Dingle and Tralee were surveyed by the Celtic Explorer in 2004, 2005 and 2007.


The majority of Dingle Bay was mapped in 2009 by the Celtic Voyager. The RV Geo, RV Keary and Cosantóir Bradán focused on the shallower waters along the coast, and the seabed around the Blasket islands in 2013.

Proteus sought to create bathymetry (water depth) maps from satellite imagery in Dingle Bay, in 2013. Although, a map was produced, there are gaps and the data is not considered accurate enough for our standards at this point in time.


INFOMAR surveys of Tralee Bay began in 2008 when Tenix LADS carried out a lidar survey of the bay. The seabed between Kerry Head and Brandon Point was mapped in 2009, 2011 and 2014 by the Celtic Voyager. The RV Geo, RV Keary and Cosantóir Bradán mapped the shallower waters along the coast of Tralee Bay, Ballyheige Bay and Brandon Bay in 2014.

INFOMAR seabed surveys in Dingle and Tralee Bays(Click image for more detailed map).

Read more about some of the survey legs on our Blog by clicking on the links below.

CV09_02 Survey of Dingle, Tralee, St. Finan's and Ballinskelligs Bays

Dingle Bay 2013

Survey Coverage polygons can be downloaded as a shapefile from our Interactive Web Data Delivery System (IWDDS).

On the IWDDS Select your area of interest. Vector datasets - Offshore - Offshore Shapefiles

 

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Bathymetry (Water Depth)

The water depth maps are known as "Bathymetry Maps".

Bathymetry Map of Dingle Bay (Click image for more detailed map).

Water depths range from 0 metres to 140 metres offshore.

Download the Dingle Bay chart pdf here

Bathymetry Map of Tralee Bay (Click image for more detailed map).

Download the Tralee Bay chart pdf here

You can download Bathymetry xyz data from IWDDS

(Data Type: Vector Datasets, Region: Offshore, Theme: Bathymetry (Survey Leg) entire survey leg or Bathymetry (Survey Line) for individual tracklines.

You can also download the bathymetry data in ArcGIS GRID format

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Satellite

Proteus sought to create bathymetry (water depth) maps from satellite imagery in Dingle Bay, in 2013.


RapidEye 5m resolution multi-spectral satellite images were used to derive the water depth. The source imagery was acquired on 10/08/2012 at 12:45:59 UTC.


Depths are calculated based on the idea that deeper water appears darker than shallower water. Different wavelengths of light penetrate water in differing amounts. Red light goes to the water surface while blue and green light can reach the seabed. Using complex mathematical analysis, light adsorption can be measured in the colour bands of a satellite image, and used to calculate water depth. Proteus used the Modular Inversion and Processing System.

Dingle Coverage

The method is limited to images showing clear shallow water, where the seabed can be seen. The biggest problem is turbidity, which occurs when water and sediment flow into bays from rivers.
Turbidity affected the mapping in several locations throughout the Bay, with some areas resulting in no coverage.

Example of a channel with turbid waters

The quality of data is deemed as poor inside the river mouth, due to high turbidity over very shallow mud banks. The data here should be used with caution. However there are still practical applications for data use.

INFOMAR do not consider the data accurate enough for our standards at this point in time.

Download the report from our Interactive Web Data Delivery System (IWDDS)

Select your area of interest and choose Reports as your Data Type

Select Satellite_2013_Dingle_Report_Of_Survey

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Lidar

This method of surveying emits two laser light beams from a sensor on-board an airplane. The red beam reaches the water surface and bounces back, while the green beam penetrates the water hits the seabed and bounces back. The difference in time between the two beams returning allows the water depth to be calculated. Digital photographs can also be taken using a downward looking geo-referenced digital camera.

In 2008, a Tenix LADS lidar survey mapped the nearshore and shallow waters in Tralee Bay. The survey area covering the main part of Tralee Bay, extending from the Seven Hogs and Rough Point in the north west, Muckaghmore Rock in the north, to Fenit Island, Barrow Harbour and Fenit Harbour in the south east and including the southern shore line.

Fenit Harbour. Lidar shaded relief on left and Lidar aerial photos on right.

All of our Charts for Tralee Bay can be downloaded in pdf format from this page.

Download Shaded Relief Bathymetry Geotiffs from our Interactive Web Data Delivery System (IWDDS)

Select your area of interest.Offshore Geotiffs - Lidar Geotiffs.

You can download Lidar xyz data from IWDDS

(Data Type: Vector Datasets, Region: Offshore, Theme: Lidar.

You can also download the Lidar data in ArcGIS GRID format

Download the report from our Interactive Web Data Delivery System (IWDDS)

Select your area of interest and choose Reports as your Data Type

Select LIDAR_2008_Report of Survey_TENIX

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Shaded Relief

The 3D appearance is achieved using software called Fledermaus. By using some vertical exaggeration, artificial sun-shading (usually as if there is a light source in the nw 315°) and colouring the depths using various colour maps, it is possible to highlight the subtle relief of the seabed.

Below is a shaded relief image of the area between Slea Head and Great Blasket Island. The area labelled scoured substrate is characterised by a rough appearance in shaded relief and it corresponds to high backscatter intensity. The area labelled sand accumulations has a smooth appearance in shaded relief and has low backscatter intensity and is shallower than the area interpreted as scoured. It is interpreted that strong currents running through Blasket Sound have scoured the seabed in this area, leaving a gravel and rock substrate. Sand has accumulated adjacent to this.

Scoured substrate and sand accumulations near Blasket Sound

Areas of intensely folded rock standing in sharp contrast to smooth sediment in Ballyheige Bay.

All of our Charts for Dingle can be downloaded in pdf format from this page.

All of our Charts for Tralee can be downloaded in pdf format from this page.

Offshore Charts for the South West can be downloaded in pdf format from this page.

Download Shaded Relief Bathymetry Geotiffs from our Interactive Web Data Delivery System (IWDDS)

Select your area of interest.Offshore Geotiffs - Bathymetry Shaded Relief Geotiffs.

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Backscatter

MBES also measures the strength of the sound returning from the seabed, known as backscatter. This helps us determine the nature of the seabed, whether it’s rocky or sandy.

Differing seafloor types, such as mud, sand, gravel and rock will have different Backscatter values depending on the amount of energy they return to the sonar head. Rocky areas will typically have high returns while soft sediments like mud are more likely to absorb energy and have low Backscatter returns. These differing values are used to generate a grey-order image (i.e. dark for high returns (rocks), bright for low returns(sand)) of the seabed which can be used to examine the nature of the seafloor.

Dingle Bay substrate can be broadly classed into two seabed textures, low backscatter intensity areas and high backscatter intensity areas. Low backscatter areas correspond to sandy and muddy substrates and are predominantly located along the central axis of the bay. Areas of high intensity correspond to bedrock outcrop and this type of seabed texture is found predominantly along the margins of the bay and near headlands. (Click image for more detailed map).

There is a sharp contrast between the low reflectivity backscatter found in Brandon Bay (light/low area in top image) to the high reflectivity backscatter found over most of the remaining area. The low reflectivity area corresponds to unconsolidated sediments and the high reflectivity backscatter to the outcropping bedrock.

All of our Charts for Dingle can be downloaded in pdf format from this page.

All of our Charts for Tralee can be downloaded in pdf format from this page.

Offshore Charts for the South West can be downloaded in pdf format from this page.

Download Backscatter Geotiffs from our Interactive Web Data Delivery System (IWDDS)

Select your area of interest.Offshore Geotiffs - Backscatter Geotiffs.

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Sediment Samples

We collect sediment samples from the seabed.

Looking at the samples alongside the bathymetry and backscatter maps allows us to group seabed areas of similar nature, and create seabed habitat maps.

Sample locations can be downloaded as a shapefile from our Interactive Web Data Delivery System (IWDDS).

On the IWDDS Select your area of interest. Vector datasets - Offshore - Offshore Shapefiles

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Seabed Habitats

The seabed substrate information has been derived from a combination of the analysis of geophysical data (multibeam echosounder bathymetry and backscatter) and groundtruthing data acquired as part of the INSS and INFOMAR seabed mapping programmes.

EMODnet Geology WP3 Seabed substrate map. This is a broadscale map (1: 250 000 scale) showing areas of similar substrate as collated  and harmonized from  EMODnet-Geology partners.  


The area contributed by GSI covers 17 indexed offshore areas within Ireland’s Territorial Claim on Continental Shelf. and is classified using Folk schema (7 classes) as developed for EMODnet Geology.

The shapefile can be downloaded from the EMODnet Geology website.

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Geology

Dingle Bay Geology
Dingle Bay is positioned between the Dingle and Iveragh peninsulas, both of which are mostly comprised of a large rock formation called the Old Red Sandstone (formed hundreds of millions of years ago during the Devonina Period).

Sandstone at Brandon Point

The bay iself may have the shape it has due to the occurrence of a package of limestone between the peninsulas, which may have been preferentially eroded over the sandstones (blue colour on the eastern side of the map). Limestone is relatively easy to weather and erode.

The general structural trend of the rocks here is northeast to southwest as show by the major faults – they are folded much like a crumpled tablecloth, with the axes of the folds running broadly along that orientiation.

In the seabed data, rock outcrops are visible on the seafloor, also following this same trend in their shapes. Even the Great Blasket island lies in this orientation, as a ridge of rock protruding from the sea.

Tralee Bay Geology
The coastline is dominated by the limestone, whereas further inland to the south it gives way to the Old Red Sandstone, the rock formation that makes up the bulk of the Dingle Peninsula. It’s possible that Tralee Bay itself is located where it is due to preferential erosion of the limestones over the sandstones.

The Bedrock datasets used in the Geology Map above are the Onshore Geology map Bedrock Geology 1:1 Million scale map produced by the GSI for the OneGeology project. It is available as a WMS. The Seabed geology map was compiled for WP4 of the EMODnet Geology project (lithology). It is available as a WMS and the Irish data can be downloaded as instructed below.

A more detailed 1:1 Million scale Geology map produced in 2014 which includes the offshore geology can be downloaded here (English)and Irish version here. A booklet "Understanding Earth processes, rocks, and the geological history of Ireland" which aims to aims to explain rock and landscape forming processes can also be downloaded.

Onshore Bedrock Geology shapefiles can be downloaded from our Interactive Web Data Delivery System (IWDDS).

On the IWDDS Select your area of interest. Vector datasets - Onshore - Bedrock

Offshore Geology shapefiles can be downloaded from our Interactive Web Data Delivery System (IWDDS).

On the IWDDS Select your area of interest. Vector datasets - Offshore - Offshore Shapefiles

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Shipwrecks

   

      

Find out all about the SS Manchester Merchant by downloading the pdf using the link below.

To view the shipwrecks in Google and to download Shipwreck Information Sheets please click here

Shipwreck locations can be downloaded as a shapefile from our Interactive Web Data Delivery System (IWDDS).

On the IWDDS Select your area of interest. Vector datasets - Offshore - Offshore Shapefiles

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Google Earth

Image of INFOMAR multibeam data for Dingle Bay in Google

To view and download our datasets in Google Earth please click here

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View data in the free iView4D (Fledermaus)

View and navigate around the merged Kerry datasets in iView4D free viewer (431Mb zipfile).

Instructions for downloading the viewer are included with the data download.

Bathymetry & Lidar data can be downloaded as a Fledermaus SD file from our Interactive Web Data Delivery System (IWDDS).

On the IWDDS Select your area of interest. Fledermaus Scenes.

Select 
bathy_lidar_kerry_5m_wgs84_NW_rainbow

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3D Map of West Kerry

Find out more here

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The Real Map of West Kerry

Find out more here

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Storymap

Kerry beneath the waves

Discover a new 3D view of Kerry. What features lie on the seafloor? How were they discovered?

Click Here to view the Kerry Story Map

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Kerry Storymap App

Free INFOMAR Story Map App for Android & iOS phones

Discover the seabed features that INFOMAR have mapped in your area. Currently story maps are available for Galway, Kerry & Waterford.

Download App

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Magnetics

Magnetic Surveys. Many rocks have a magnetic component and this magnetic field can be measured by a magnetometer towfish. These maps are used to aid in the production of geological maps and are also commonly used during mineral exploration. Manmade objects containing iron and other metals will also produce a magnetic field, so the magnetometer can also be used to detect shipwrecks and debris on the ocean floor.

Magnetic Map Offshore Dingle

A large magnetic anomaly at the entrance of Dingle Bay was found. It is indicated by a significant rise of magnetic field values, in the order of 2000 gammas. The Royal Admiralty Charts in the area indicates more ‘local magnetic anomalies’, which line up along a heading of approx 052 degrees. Previous surveys in this area reveal indications of a Tertiary Dyke, which is typically the kind of source that are assumed to cause anomalies.

    

Magnetic Anomaly observed in west Kerry region.  

A Marine Magnetics SeaSPY Magnetometer with a 200m tow cable was used to gather regional magnetic data. The magnetometer was deployed only when the risk of snagging on obstacles was at an acceptable level. Data quality from the magnetometer was generally good. During periods of high swell the magnetometer was recovered to avoid damage to the instrument.
    

Magnetic data can be downloaded from Interactive Web Data Delivery System (IWDDS).

In .ers format. Select your area of interest. Data Type: Gridded datasets, Region: Offshore, Theme: Magnetics

In ArcGIS GRID format. Select your area of interest. Data Type: ArcGIS GRIDS, Region: Offshore ArcGIS , Theme: Magnetics ArcGIS GRID

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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

Follow these links to your area of interest on the INFOMAR website:

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