Fluvial Audit of the Afon Tywi

The Afon Tywi in Carmarthenshire is a large actively eroding river, designated as a Special Area of Conservation (SAC) for its migratory fish, and as a Site of Special Scientific Interest (SSSI) for various features including river habitat, river shingle invertebrates and little ringed plover. The river is unusually active in the middle reaches, sometimes moving as much as 50 m in a single year, and the various species for which the river is designated depend on the river remaining active. In order to inform current and future river management, a fluvial audit of the past and present geomorophology of the Afon Tywi was carried out. This consists of a detailed technical report including identification of the most active river sections based on historic maps, a timeline of the river indicating key events such as major floods, and maps showing the geomorphology and sediment character of the river. Advice is also provided on the future sustainable management of the Tywi as an active shingle river. This dataset consists of the results from the Fluvial Audit of the Afon Tywi which describes and spatially maps the past and present fluvial geomorphology of the Tywi catchment. The aim of this data capture was to: - Develop an understanding of the dynamic geomorphology of the Afon Tywi. Specific aims include: - Describe and map the fluvial geomorphology of the Tywi catchment past and present using a GIS system. - Interpret the data gathered in the context of past and present human activity, including a risk assessment of consented activities. - Provide advice on the future management of the Tywi SAC for use as a management and casework decision-making tool with regards to future bank reinforcement work, flood defence activities, aggregate extractions etc.

Identifier: NRW_DS111562

Alternative Title

Archwiliad o Afon Tywi

Metadata Language: English

Lineage: The project had numerous stages as follows: Stage 1: Catchment Overview - literature study and GIS analysis of the catchment characteristics. Stage 2: Hydrological Assessment. Stage 3: The Fluvial Audit - Map and aerial photograph-based assessment; Field-based assessment; Detailed survey of sediment character; Linking map, field-based and laboratory results; Geomorphic impact of floods; Assessing sediment stores on the Afon Tywi; Impacts of human activity (including information from questionnaire of riparian users); Detailed analysis of case-study reaches. Stage 4: Sensitivity assessment to help evaluate risk - Analysis of sediment balance at the points of gravel extraction; Strategy for assessing the impact of existing and potential gravel extraction. Stage 5: Sediment transport modelling. Stage 6: Risk assessment and management advice.

Dataset Reference Date (Publication): 1953-12-31

Temporal Extent

Begin date: 1890-01-01

End date: 1953-12-31

Topic category

Environment
Inland waters
Biota

Owner

Natural Resources Wales (NRW)

Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales

http://naturalresources.wales/?lang=en

Originator

Geography and Environmental Management Research Unit, University of Gloucestershire

Extent

Geographic Extent: Wales (WLS)

Format Type and Description

Geographic Information System ()

Specification

[A] Report: Adobe Portable Document Format versions of Volume 1 and 3 of project report. Paper copy of all volumes- Volume 1: Technical Report; Volume 2: Maps Report; Volume 3: Short report for use by river managers. [B] GIS Data: MapInfo tables- Species data, Bank protection, Gravel extraction, Channel line

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
Degree: false

Lineage: The project had numerous stages as follows: Stage 1: Catchment Overview - literature study and GIS analysis of the catchment characteristics. Stage 2: Hydrological Assessment. Stage 3: The Fluvial Audit - Map and aerial photograph-based assessment; Field-based assessment; Detailed survey of sediment character; Linking map, field-based and laboratory results; Geomorphic impact of floods; Assessing sediment stores on the Afon Tywi; Impacts of human activity (including information from questionnaire of riparian users); Detailed analysis of case-study reaches. Stage 4: Sensitivity assessment to help evaluate risk - Analysis of sediment balance at the points of gravel extraction; Strategy for assessing the impact of existing and potential gravel extraction. Stage 5: Sediment transport modelling. Stage 6: Risk assessment and management advice.

Keywords

GEMET - INSPIRE themes, version 1.0

Land cover

Type: Theme

Citation

Date (Publication): 2008-06-01

Code: geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme

Keywords

NRW Thesaurus

fluvial
fluvial geomorphology
fluvial processes
rivers (see also specific river names)
river Tywi (afon Tywi)
Upper Reaches of Afon Tywi
Special Areas of Conservation (SAC) (see also Candidate Special Areas of Conservation cSAC)
SSSI (Sites of Special Scientific Interest)
geomorphology

Type: Theme

Citation

Date (Publication): 2023-12-31

Code: geonetwork.thesaurus.local.theme.converted_nrw-keywords

Code: British National Grid (EPSG::27700)

Content Information

NRW Profile

Custom Elements

NRW Related Title: A fluvial audit of the Afon Tywi : Volume 1 : technical report

NRW Related Title: A fluvial audit of the Afon Tywi : Volume 2 : map volume

NRW Related Title: A fluvial audit of the Afon Tywi : Volume 2 : map volume (addendum revised figure 16d)

NRW Related Title: A fluvial audit of the Afon Tywi : Volume 3 : summary report

Constraints

Limitations on Public Access and Use

Restriction type: Other restrictions

Access Constraints Directive

Limitations: no limitations

Access Constraints Text

Other constraints: This dataset contains 'simple derived data' which is jointly owned by NRW and the Ordnance Survey in the form of river bank GIS layers (erosion, bank protection etc). NRW may release, publish or disseminate this dataset freely, providing recipients are made aware of use restrictions (see below). Data not derived from OS products have no access or use restrictions. Third party recipients may reproduce, disseminate and re-use 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. To avoid using old information, we recommend that the latest version is obtained from the original source.

Use Constraints

Use constraints type: Other restrictions

Other constraints: Third parties seeking to re-use this data require a OS Derived Data Licence issued by NRW. It allows re-use, reproduction and dissemination in any format or medium but only for non-commercial purposes, according to the terms and conditions of the Licence. Those seeking commercial re-use require a commercial licence available from the OS.

Metadata

File Identifier: 4f4c4942-4343-5764-6473-313131353632 XML

Metadata Language: English

Parent Identifier: Fluvial Audits of Welsh River Systems
NRW_DS101833

Resource type: Dataset

Metadata Date: 2024-05-30T15:36:15.999Z

Metadata Standard Name: NRW

Metadata Standard Version: 1.0

pointOfContact

Natural Resources Wales (NRW)

Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales

http://naturalresources.wales/?lang=en

Publishing Body

Access the portal

Full access to the portal and metadata.

Fluvial Audit of the Afon Tywi

Identification

Temporal Extent

Extent

Extent

Distribution

Quality

Data quality

Keywords

Keywords

Citation

Keywords

Citation

Spatial Reference System

Content

Content Information

NRW Profile

Custom Elements

Constraints

Constraints

Limitations on Public Access and Use

Access Constraints Directive

Access Constraints Text

Use Constraints

Metadata

Metadata

Publishing Body