Marine Aggreggates Levy Sustainability Fund (MALSF) Outer Bristol Channel Marine Habitat Study (Biomor 4 report) - Multibeam Data (3rd Party Data)

The Outer Bristol Channel Marine Habitat Study was a multifaceted project involving scientific investigation Interpretation and education in an area with potential marine aggregate resources. The Bristol Channel and Severn Estuary boarded by Wales and England, has the largest tidal range in UK waters and is a multiple-use environment. Natural resource activities include aggregate extraction, fisheries and wind-farm developments. Marine nature conservation is prominent with Lundy Marine Nature Reserve in the south and, under the EC Habitats Directive, a Special Area of Conservation. The purpose of this study was to undertake a variety of work to collect and provide data and interpretations on the current physical state of the sea bed environment in terms of biology, sediment, geology and morphology. The study was jointly lead by the British Geological Survey (BGS) and Amgueddfa Cymru - National Museum Wales (NMW) and supported by core funding from the Aggregate Levy Sustainable Fund (ALSF) in Wales and England. Additional support came from The Crown Estate and the British Marine Aggregate Producers Association (BMAPA). There were numerous aims to this project, as outlined in the report (see related titles). This dataset just covers one specific aim: To undertake a marine geophysical survey utilising multibeam, sidescan sonar and sub-bottom seismic reflection systems. This dataset comprises of multibeam bathymetry data for the Outer Bristol Channel, including raw data files, cruise logs, calibration data, processed data and geotiffs. As well as the sidescan sonar and sub bottom profile data. The purpose of this data capture was to collect multibeam data for the Biomor project to give a 3D image of the seabed, and enable display of sandbanks, ascertain slope steepness and identify other seabed features. Additional backscatter and acoustic data along with benthic sampling enabled the multibeam data to be used to classify and map the seabed.

Identification

Identifier
EXT_DS114487
Alternative Title
  • Astudiaeth o Gynefin Morol Mor Hafren Allanol - data aml-donfedd
Metadata Language
English
Lineage

The geophysical data was collected using multibeam echosounder, sidescan sonar and sub bottom profile. The geophysical survey strategy was devised based on eleven parallel survey corridors aligned generally along the direction of the peak tidal currents. The following geodetic parameters were used for the geophysical surveys: - Ellipsoid WGS84 - Semi major axis 6 378 137 m - Projection UTM Zone 30N - Central Meridian 3W Prior to commencing the multibeam systems a full calibration of the multibeam system was undertaken in a series of stages. In total 2177 line km of multibeam data were acquired during the two surveys. The sidescan sonar used was a Edgetech MP-X digitial multipulse sidescan tow-fish was used during the first survey works. During the second survey sidescan data were acquired using a digital Klein 5000 multibeam sidescan towfish. A total of 1935 line km of sidescan data was collected. The seismic reflection devices (boomer profiling) was used to assess the subbottom profile. This technique uses sound entery, formed by different frequencies to partly reflect off the seabed and in some measure penetrates below the seabed. The signal travelling though the different media beneath the sea bed is the partially reflected and partially refracted every time a change on the acoustic impedance occurs. In this way acoustic discontinuities are highlighted and can be correlated to geological features. These files were then used to calculate the thickness of the superficial sediment units and in correlation with datasets such as the sidescan and multibeam data and are used to help map geological features. All data was processed by Netsurvey Ltd as per accepted practice for multibeam data, and included full calibration of the multibeam system.
Additional Information

The outputs include detailed research reports on the survey coupled with a range of outreach measures concerned with sea bed survey and the marine aggregate industry.
Dataset Reference Date (Publication)
2006-11-30
Owner
  Marine Aggregates Levy Sustainability Fund -
c/o CEFAS, Pakefield Road, Lowestoft, NR33 0HT, England
http://www.marinealsf.org.uk/
Originator
  Marine Aggregates Levy Sustainability Fund -
c/o CEFAS, Pakefield Road, Lowestoft, NR33 0HT, England
http://www.marinealsf.org.uk/
 

Extent

Extent

Geographic Extent
Bristol Channel
Geographic Extent
Irish Sea
Geographic Extent
Celtic Sea
N
W
E
S
Map representing the geographic extent of the dataset


 

Vertical Extent

Medin Extent Keyword

benthic boundary layer

Vertical Extent

Minimum value (metres)
-10
Maximum value (metres)
-60
Vertical CRS
 
 

Distribution

Format Type and Description
  • Geographic Information System ()

    Specification

    All in digital form. Includes full resolution GeoTiffs of multibeam data, fledermaus .SD files, raw xyz data files, vessel logs, calibration files, navigation files, raw .gsf files. Biomor report, operational report (BGS), geophysical (sidescan sonar and surface tow boomer) raw data, processed data and logs.

 

Quality

Data quality

Quality Scope
Dataset
Conformity
Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services
Explanation

This dataset has not been assessed for conformance to the referenced INSPIRE regulation.
Degree
false
Lineage

The geophysical data was collected using multibeam echosounder, sidescan sonar and sub bottom profile. The geophysical survey strategy was devised based on eleven parallel survey corridors aligned generally along the direction of the peak tidal currents. The following geodetic parameters were used for the geophysical surveys: - Ellipsoid WGS84 - Semi major axis 6 378 137 m - Projection UTM Zone 30N - Central Meridian 3W Prior to commencing the multibeam systems a full calibration of the multibeam system was undertaken in a series of stages. In total 2177 line km of multibeam data were acquired during the two surveys. The sidescan sonar used was a Edgetech MP-X digitial multipulse sidescan tow-fish was used during the first survey works. During the second survey sidescan data were acquired using a digital Klein 5000 multibeam sidescan towfish. A total of 1935 line km of sidescan data was collected. The seismic reflection devices (boomer profiling) was used to assess the subbottom profile. This technique uses sound entery, formed by different frequencies to partly reflect off the seabed and in some measure penetrates below the seabed. The signal travelling though the different media beneath the sea bed is the partially reflected and partially refracted every time a change on the acoustic impedance occurs. In this way acoustic discontinuities are highlighted and can be correlated to geological features. These files were then used to calculate the thickness of the superficial sediment units and in correlation with datasets such as the sidescan and multibeam data and are used to help map geological features. All data was processed by Netsurvey Ltd as per accepted practice for multibeam data, and included full calibration of the multibeam system.
 

Keywords

Keywords

GEMET - INSPIRE themes, version 1.0
Type
Theme

Citation

Date (Publication)
2008-06-01
Code
geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme

Keywords

NRW Thesaurus
  • Bristol Channel
  • multibeam
  • Carmarthen Bay and Estuaries SAC
  • Bae Caerfyrddin/Carmarthen Bay SPA
  • Pembrokeshire Marine SAC
  • Biomor 4
  • benthic marine habitats
  • 3rd Party Data
  • Third Party Data
Type
Theme

Citation

Date (Publication)
2023-12-31
Code
geonetwork.thesaurus.local.theme.converted_nrw-keywords

Keywords

SeaDataNet Parameter Discovery Vocabulary
Type
Theme

Citation

Date (Revision)
2021-01-06
Code
geonetwork.thesaurus.external.theme.rdf+xml
 

Spatial Reference System

Code
Latitude and Longitude (EPSG::4326)
 

Content

Content Information

NRW Profile

Custom Elements

NRW Related Title

Biomor 4 : the outer Bristol Channel marine habitat study : appendices
NRW Related Title

Biomor 4 : the outer Bristol Channel marine habitat study
NRW Related Title

The Outer Bristol Channel marine habitat study
NRW Related Title

Outer Bristol channel marine habitat study - 2003 investigations and resluts
NRW Related Title

Outer Bristol Channel marine habitat study
 

Constraints

Constraints

Limitations on Public Access and Use

Restriction type
Other restrictions
 

Access Constraints Directive

Limitations
no limitations
 

Access Constraints Text

Other constraints

This dataset is wholly owned by Marine Aggreggates Levy Sustainability Fund NRW may provide access to this dataset on request in some circumstances. However, enquirers are advised to obtain a copy from the owner/originator directly, rather than NRW. NRW may NOT publish or disseminate it in its entirety.
 

Use Constraints

Use constraints type
Other restrictions
Other constraints

© Marine Aggreggates Levy Sustainability Fund NRW does NOT grant permission to third parties to re-use or disseminate this dataset. Those seeking such permission should approach the originator directly.
 
 
 

Metadata

Metadata

File Identifier
4f4c4942-4343-5764-6473-313134343837 XML
Metadata Language
English
Parent Identifier
Multibeam Acoustic Data Index

NRW_DS121633
Resource type
Dataset
Metadata Date
2026-03-03T15:34:47.15Z
Metadata Standard Name
NRW
Metadata Standard Version

1.0

pointOfContact
  -
 
 

Publishing Body

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