Survey of Lakes in the Migneint-Arenig-Dduallt Proposed Site of Special Scientific Interest (pSSSI) Special Area of Conservation (SAC) and Special Protection Area (SPA)
Arolwg o lynnoedd yn SoDdGAa/ACA/AGA Migneint-Arenig-Dduallt

  • English
  • wel
  • All

The Migneint-Arenig-Dduallt Proposed Site of Special Scientific Interest (pSSSI) and Special Area of Conservation (SAC) is situated in North Wales in the Snowdonia National Park. The pSSSI/SAC boundary marks the limit of a large upland block located along the eastern fringe of the National Park. The primary reasons for the site qualifying for SAC status are the large areas of blanket bog, a priority habitat under the Habitats Directive, and the upland European dry heath. Other qualifying features include two Annex I habitat lake types: (1) oligotrophic to mesotrophic standing waters with vegetation of the Littorelletea uniflorae and/or of the Isoeto-Nanojuncetea, and (2), natural dystrophic lakes and ponds. The limnological surveys (surveys of inland water) focus on the collation of site and catchment data and the collection of new data on lake bathymetry, water quality and macrophyte assemblages. A particular focus is an assessment of the current acidification and conservation status of the four lake sites. A preliminary assessment of whether the lakes are in favourable condition, as defined in the Habitats Directive, is also outlined. The primary aim of this project was to survey four lakes in the Migneint-Arenig-Dduallt pSSSI/SAC in order to build up CCWs datasets on Welsh lakes. The information collected is required for conservation site assessments, ecological quality judgements for site condition reporting, contributions to site management plans and assistance with casework issues.

Identification

Dynodydd
Identifier
NRW_DS109993
Teitl Amgen
Alternative Title
Laith Metadata
Metadata Language
English
Lineage

Bathymetric Surveys- undertaken at Llynnau Tryweryn, Hesgyn and Hiraethlyn in August 2002. Echo sounding transects were run in a small boat between identifiable points on the shore and marked onto field maps, the transect end point locations were also recorded using a Geographical Positioning System (GPS). This produced a cross sectional profile of the lakebed on a paper chart for each transect. Lake areas, volumes and perimeter lengths calculated using planimetry. Standard physical and morphometric parameters were calculated from the survey data. No further field investigation were required at Llyn Conwy which had sufficient morphometric information from a 1986 survey. Physico-chemical survey-Water samples collected and temperature measured at the lake outflow. Temperature and dissolved oxygen profiles taken at the deepest part of each lake. Samples for soluble reactive phosphorus (SRP), total phosphorus (TP) and total nitrogen (TN) and filter papers for chlorophyll a were analysed. Acid neutralising capacity (ANC) estimated. Aquatic macrophyte survey- zonation and maximum growing depth examined using transects, all submerged floating leaved and emergent plants recorded. Plant distribution and abundance assessed and lake type determined.
Dyddiad cyfeirnod y set ddata (Cyhoeddiad)
Dataset Reference Date (Publication)
2003-09-30

Temporal Extent

Begin date
2002-01-31
End date
2003-12-31
 
Categori pwnc
Topic category
  • Inland waters
    Inland waters
  • Environment
    Environment
Perchennog
Owner
  Natural Resources Wales (NRW) -
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
Cychwynnwr
Originator
  Centre for Ecology and Hydrology (CEH) -
Environment Centre Wales, Deiniol Road, Bangor, Gwynedd, LL57 2UW, Wales
http://www.ceh.ac.uk/
 

Extent

Extent

Hyd
Geographic Extent
Wales (WLS)
N
W
E
S
Map representing the geographic extent of the dataset


 
 

Distribution

Fformat - Math a Disgrifiad
Format Type and Description
  • Documents ( )

    Specification

    [A] Report (MS Word, pdf-format) [B] Data in spreadsheet format (MS Excel)

 

Quality

Ansawdd Data
Data quality

Cwmpas Ansawdd
Quality Scope
Dataset
Dataset
Cydymffurfiad
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

Bathymetric Surveys- undertaken at Llynnau Tryweryn, Hesgyn and Hiraethlyn in August 2002. Echo sounding transects were run in a small boat between identifiable points on the shore and marked onto field maps, the transect end point locations were also recorded using a Geographical Positioning System (GPS). This produced a cross sectional profile of the lakebed on a paper chart for each transect. Lake areas, volumes and perimeter lengths calculated using planimetry. Standard physical and morphometric parameters were calculated from the survey data. No further field investigation were required at Llyn Conwy which had sufficient morphometric information from a 1986 survey. Physico-chemical survey-Water samples collected and temperature measured at the lake outflow. Temperature and dissolved oxygen profiles taken at the deepest part of each lake. Samples for soluble reactive phosphorus (SRP), total phosphorus (TP) and total nitrogen (TN) and filter papers for chlorophyll a were analysed. Acid neutralising capacity (ANC) estimated. Aquatic macrophyte survey- zonation and maximum growing depth examined using transects, all submerged floating leaved and emergent plants recorded. Plant distribution and abundance assessed and lake type determined.
 

Keywords

Allweddair
Keywords

GEMET - INSPIRE themes, version 1.0
Math
Type
Theme
Theme

Dyfyniad
Citation

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

Allweddair
Keywords

NRW Thesaurus
  • Llyn Hesgyn
  • marine and freshwater inventory
  • Physico-chemical survey
  • Lakes (Limnology)
  • Bathymetric survey
  • Llyn Hiraethlyn
  • site management
  • Migneint-Arenig-Dduallt SAC
  • aquatic macrophytes
  • Ecological quality
  • Llyn Conwy
  • Llyn Tryweryn
  • Favourable condition
  • Habitats Directive (Directive 92/43/EEC) (EC Habitats Directive) (European Community Habitats Directive)
  • Conservation site assessments
Math
Type
Theme
Theme

Dyfyniad
Citation

Dyddiad (Cyhoeddiad)
Date (Publication)
2026-08-27
Code
geonetwork.thesaurus.local.theme.converted_nrw-keywords
 

Spatial Reference System

Code
British National Grid (EPSG::27700)
 

Content

Gwybodaeth Cynnwys
Content Information

Proffil CNC
NRW Profile

Elfennau CNC
Custom Elements

NRW Related Title

Strategic CCW conservation lake survey : a survey of lakes in the Migmeint - Arenig - Dduallt pSSSI/SAC/SPA, Wales 2002 - 03 : final report
 

Constraints

Constraints

Limitations on Public Access and Use

Math o Gyfyngiad
Restriction type
Other restrictions
Other restrictions
 

Access Constraints Directive

Limitations
no limitations
 

Access Constraints Text

Other constraints

There are no access restrictions to this data. NRW may release, publish or disseminate it freely.
 

Use Constraints

Cyfyngiadau Defnyddio
Use constraints type
Other restrictions
Other restrictions
Other constraints

© CNC/NRW 2003 There are no use restrictions on this data. Recipients may re-use, reproduce, disseminate this data free of charge in any format or medium, provided they do so accurately, acknowledging both the source and NRW's copyright, and do not use it in a misleading context. It is the recipient's responsibility to ensure the data is fit for the intended purpose, that dissemination or publishing does not result in duplication, and that it is fairly interpreted. Advice on interpretation should be sought where required. To avoid re-using old data, users should periodically obtain the latest version from the original source.
 
 
 

Metadata

Metadata

Dynodydd Ffeil
File Identifier
4f4c4942-4343-5764-6473-313039393933 XML
Laith Metadata
Metadata Language
English
Parent Identifier
Welsh Lakes Survey and Monitoring

NRW_DS123035
Math o adnodd
Resource type
Dataset
Dataset
Dyddiad Metadata
Metadata Date
2026-09-28T11:42:42.072Z
Enw Safonol Metadata
Metadata Standard Name
NRW
Fersiwn Metadata
Metadata Standard Version

1.0

Pwynt Cyswllt
pointOfContact
  Natural Resources Wales (NRW) -
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
 
 

Publishing Body

Access the portal