Case study:Afon Merin Natural Process Restoration

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Location: 52° 23' 56.58" N, 3° 46' 27.57" W
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Project overview

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Status In progress
Project web site
Themes Environmental flows and water resources, Fisheries, Flood risk management, Habitat and biodiversity, Hydromorphology, Land use management - forestry, Monitoring, Water quality
Country Wales
Main contact forename Ieuan
Main contact surname Davies
Main contact user ID User:Ieu_Dav
Contact organisation Natural Resources Wales
Contact organisation web site http://naturalresources.wales/?lang=en
Partner organisations
This is a parent project
encompassing the following
projects
Generic site pic

Project summary

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The site offered the potential to undertake a pilot study of low cost high nature value interventions on Welsh Government Woodland Estate. While seemingly in a natural state, the rivers was incised and disconnected from the wider flood plain, with a lack of suitable gravels for the resident native Brown Trout population. Felling commenced in 2018 and some of the timber was used to begin ditch blocking and creating leaky dams within the main channel. Early observations showed that the results had been positive with the hydrological systems soon renaturalising within the valley floor, wet areas were developing and the main channel began to take on a more braided characteristic by occupying historic channels. In channel flow diversity increased markedly allowing a more complex sediment matrix to appear.

Monitoring surveys and results

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Pre work aerial studies of the area and fixed point photography at key areas through the valley have allowed a gross study of early geomorphological changes within the system, including stream number and width, and changes within the network of wet areas across the valley floor. Aberystwyth University are undertaking flow measurements and will continue to do so over an extended time period. Ecological studies will be undertaken across this and a control site on the same waterbody to monitor changes.

Lessons learnt

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The implementation of this scheme on Welsh Government Woodland Estate has shown that there are high value gains possible at low cost inputs which can be imnplemented alongside current Forest management techniques. These can yield multiple benefits and studying these allows us to put forward a case for spreading this work and ethos across the wider Woodland Estate with potential for large scale projects. The multiple benefits are closely aligned with NRW's wider Corporate and Business plans and better ways of working which look to generate positive outcomes through nature based solutions giving positive benefits across a broad spectrum of habitats, species and communities.


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Catchment and subcatchment



Site

Name
WFD water body codes
WFD (national) typology
WFD water body name
Pre-project morphology
Reference morphology
Desired post project morphology
Heavily modified water body
National/international site designation
Local/regional site designations
Protected species present
Invasive species present
Species of interest
Dominant hydrology
Dominant substrate
River corridor land use
Average bankfull channel width category
Average bankfull channel width (m)
Average bankfull channel depth category
Average bankfull channel depth (m)
Mean discharge category
Mean annual discharge (m3/s)
Average channel gradient category
Average channel gradient
Average unit stream power (W/m2)


Project background

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Project started
Works started
Works completed
Project completed
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Total cost (k€)
Benefit to cost ratio
Funding sources

Cost for project phases

Phase cost category cost exact (k€) Lead organisation Contact forename Contact surname
Investigation and design
Stakeholder engagement and communication
Works and works supervision
Post-project management and maintenance
Monitoring



Reasons for river restoration

Mitigation of a pressure
Hydromorphology
Biology
Physico-chemical
Other reasons for the project


Measures

Structural measures
Bank/bed modifications
Floodplain / River corridor
Planform / Channel pattern
Other
Non-structural measures
Management interventions
Social measures (incl. engagement)
Other


Monitoring

Hydromorphological quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative

Biological quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative

Physico-chemical quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative

Any other monitoring, e.g. social, economic

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative


Monitoring documents



Additional documents and videos


Additional links and references

Link Description

Supplementary Information

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