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River Dee/ Afon Dyfrdwy SSSI Restoration Management Report March 2013

B1867400 River Dee SSSI Restoration Management Report_March 2013_Final.doc

Document Control Sheet BPP 04 F8 Version 14 July 2012

Project: River Dee SSSI Restoration Project No: B1867400 Client: Environment Agency Document Title: Management Report Ref. No:

Originated by Checked by Reviewed by Approved by

NAME NAME NAME NAME ORIGINAL Alison Flynn Elinor Phillips

Elinor Phillips Jon Barnes

Andrew Brookes

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February 2013 Document Status Draft for client comments

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Andrew Brookes Elinor Phillips Elinor Phillips Andrew Brookes

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INITIALS

February 2013 Document Status Pre-consultation comments addressed

NAME NAME NAME NAME REVISION Elinor Phillips Helena Parsons Helena Parsons Andrew Brookes

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INITIALS

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March 2013 Document Status Final post consultation

NAME NAME NAME NAME REVISION

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Document Status

Jacobs U.K. Limited This document has been prepared by a division, subsidiary or affiliate of Jacobs U.K. Limited (“Jacobs”) in its professional capacity as consultants in accordance with the terms and conditions of Jacobs’ contract with the commissioning party (the “Client”). Regard should be had to those terms and conditions when considering and/or placing any reliance on this document. No part of this document may be copied or reproduced by any means without prior written permission from Jacobs. If you have received this document in error, please destroy all copies in your possession or control and notify Jacobs. Any advice, opinions, or recommendations within this document (a) should be read and relied upon only in the context of the document as a whole; (b) do not, in any way, purport to include any manner of legal advice or opinion; (c) are based upon the information made available to Jacobs at the date of this document and on current UK standards, codes, technology and construction practices as at the date of this document. It should be noted and it is expressly stated that no independent verification of any of the documents or information supplied to Jacobs has been made. No liability is accepted by Jacobs for any use of this document, other than for the purposes for which it was originally prepared and provided. Following final delivery of this document to the Client, Jacobs will have no further obligations or duty to advise the Client on any matters, including development affecting the information or advice provided in this document. This document has been prepared for the exclusive use of the Client and unless otherwise agreed in writing by Jacobs, no other party may use, make use of or rely on the contents of this document. Should the Client wish to release this document to a third party, Jacobs may, at its discretion, agree to such release provided that (a) Jacobs’ written agreement is obtained prior to such release; and (b) by release of the document to the third party, that third party does not acquire any rights, contractual or otherwise, whatsoever against Jacobs and Jacobs, accordingly, assume no duties, liabilities or obligations to that third party; and (c) Jacobs accepts no responsibility for any loss or damage incurred by the Client or for any conflict of Jacobs’ interests arising out of the Client's release of this document to the third party.


Executive summary

The Environment Agency (EA) commissioned Jacobs to undertake a joint geomorphology and ecology study of the River Dee/ Afon Dyfrdwy. The river has a high conservation value and is designated as a Site of Special Scientific Interest (SSSI) and a Special Area of Conservation (SAC). The features contributing to the SSSI and SAC designations include Ranunculus communities, floating water plantain, Atlantic salmon, bullhead, lamprey, otter, club tailed dragonfly and fluvial geomorphology. Currently most of the SSSI/ SAC is assessed as being in unfavourable condition, due to a number of historical and current pressures. The purpose of this study is to develop a restoration vision of the whole river catchment, identifying where the main pressures are (detailed in the accompanying Technical Report) and outlining restoration measures to help achieve favourable condition (presented in this Management Report). The River Dee/ Afon Dyfrdwy is a transboundary river which flows through Wales and England. As a result, a number of Statutory Bodies have been involved with this project including the Environment Agency (EA, England and Wales), Natural England (NE) and Countryside Commission for Wales (CCW). The Dee catchment has been divided into four parts based on the river’s geomorphology: the Upper Dee (including headwater tributaries), Middle Dee, Lower Dee and Afon/ River Ceiriog. The upland tributaries of the Upper Dee and most of the upper Afon/ River Ceiriog have some localised modifications but are largely natural with geomorphology and ecology habitat suitability considered to be of high quality. Most pressures on habitat suitability on the River Dee/ Afon Dyfrdwy SSSI are considered to occur on the main stem river, namely:

• Absence of tree cover and grass lined bank tops

• Poaching from livestock

• Bank protection

• Embankments

• Channel realignment

• Major and minor weirs.

Five restoration measures have been developed based on field evidence and data from previous studies:

• Riparian zone management

• Bank protection removal

• Unmanaged and managed embankment retreat

• Channel realignment

• Removal or modification of weirs These measures have been classified according to the degree of intervention required including riparian zone management, natural recovery, assisted natural recovery and significant channel restoration. The sections of river within the Dee/ Dyfrdwy catchment which would benefit from these restoration measures have been identified and a selection of these sites is presented on individual plans. Flow in the River Dee/ Afon Dyfrdwy is very highly regulated for public water supply and flood risk by reservoirs Bala Lake/ Llyn Tegid, Llyn Celyn and Llyn Celyn, which are located in the Welsh mountains. This flow regulation has resulted in increased


low flows and decreased high flows in the main stem Dee/ Dyfrdwy, which may mean the river is less able to carry out geomorphological processes (such as bank erosion). This effect of flow regulation on geomorphology is a key limitation in choosing suitable restoration measures/ actions for this vision. The Statutory Bodies involved with this project recognise that implementation of the restoration measures will require effective and positive engagement with landowners, land managers and stakeholders. This Management Report forms part of a long term strategy (over a period of 20-30 years), although it is anticipated that some actions can be implemented relatively quickly. From the 1st April 2013, Natural Resources Wales will take over the functions currently carried out by the Countryside Council for Wales, Environment Agency Wales and Forestry Commission Wales.


Contents

1 Introduction 1

1.1 The River Dee/ Afon Dyfrdwy 1

1.2 Why do we need to restore the SSSIs of the River Dee? 1

1.3 European Directives 2

1.4 Aim and objectives of the Management Report 3

1.5 Stakeholder involvement 4

2 The River Dee/ Afon Dyfrdwy SSSIs and SAC 5

2.1 Overview 5

2.2 Geology and land use 8

2.3 Channel changes and past practices 8

2.4 Hydrology 9

2.5 Ecology 9

2.6 Pressures and impacts 10 2.6.1 Condition assessment 10 2.6.2 Desk study 14 2.6.3 Field survey 14 2.6.4 Key findings 15

3 Potential solutions 21

3.1 Selecting restoration solutions 21

3.2 Meeting WFD objectives 21

3.3 Creating a restoration vision 22

3.4 ‘Room for the river’ approach 26

3.5 Types of restoration 27

3.6 Descriptions of the restoration measures 29 3.6.1 Riparian zone restoration 29 3.6.2 Channel restoration/ rehabilitation 30

4 Reach-scale restoration options 43

4.1 Organisation of the options 43

4.2 Restoration plans 43

5 Implementing the plan 62

5.1 Working with landowners and land managers 62

5.2 Prioritisation and cost 64

5.3 Shaping the actions 65

5.4 An opportunity 65

5.5 Delivery mechanisms and sources of funding 68 5.5.1 Welsh Dee Trust 68 5.5.2 Water Framework Directive Improvement Fund 68 5.5.3 Diffuse Water Pollution Plan 69 5.5.4 European funding 69 5.5.5 Environmental Stewardship Schemes 70 5.5.6 Glastir 70


5.5.7 Catchment Sensitive Farming 71 5.5.8 Forestry Commission English Woodland Grant Scheme 71 5.5.9 Glastir Woodland Creation Scheme 71 5.5.10 Catchment Restoration Fund (England) 72 5.5.11 Partnership Projects in Wales 72

5.6 Current examples of restoration schemes in the Dee catchment 72

6 References 74

Appendix A Consultation report 75 For quick reference: Individual plans showing potential restoration options for specific river reaches can be found in Section 4 on the following pages: Location SSSI Designation Page number

Afon Mynach – between Glan-yr-afon and Frongoch

Afon Dyfrdwy (River Dee) SSSI 46

Afon Meloch – near Cefn-ddwysarn


Afon Ceiriog – Llanarmon Dyffryn Ceiriog


Upper Dee – near Llandrillo Afon Dyfrdwy (River Dee) SSSI 49 Upper Dee – Cynwyd Afon Dyfrdwy (River Dee) SSSI 50 Upper Dee – Corwen Afon Dyfrdwy (River Dee) SSSI 51 Middle Dee – Carrog Afon Dyfrdwy (River Dee) SSSI 52 Lower Dee – Dee meanders

River Dee (England) SSSI 53

Lower Dee – between Farndon and Aldford

River Dee SSSI 54

Weirs Afon Dyfrdwy SSSI and River Dee SSSI

55-60


Glossary

Terminology Definition

Afon Dyfrdwy (River Dee) SSSI

The River Dee/ Afon Dyfrdwy is divided into two SSSIs. The Afon Dyfrdwy (River Dee) SSSI specifically refers to the Welsh SSSI that is managed by EAW and CCW

Berm Deposit of fine material along the edges of a river channel. This may have formed in the Lower Dee meanders as a result of flow regulation, reducing the capacity of the river to carry sediment, and resulting in deposition

Catchment Area drained by a river and its tributaries

Deposition Laying down of part, or all, of the sediment load of a stream on the bed, banks or floodplain. Mostly occurs as high flows recede. The process forms various sediment features such as bars, berms and floodplain deposits

Ecological status Surface waters are classified as being of good ecological status when each of the quality elements that represent indicators of ecological quality of the water body is classified as being good or high. The quality elements fall into three categories: i) biological quality elements, ii) chemical and physicochemical quality elements and iii) hydromorphological quality elements

Erosion Removal of sediment or bedrock from the bed or banks of the channel by flowing water. Mostly occurs during high flows and flood events. Forms various river features such as scour holes and steep outer banks

Favourable condition

Description of the condition of the features for which a SSSI or SAC has been designated. Favourable condition means that all of the targets for the mandatory attributes (population and habitat) used to assess a feature have been met. If a SSSI site is in Favourable Condition, it means that the site is being adequately conserved and is meeting its 'conservation objectives'

Floodplain A floodplain is flat or nearly flat land adjacent to a stream or river, stretching from the banks of its channel to the base of the enclosing valley walls and (under natural conditions) experiences flooding periods of high discharge

Geomorphology The study of landforms and the processes that create them

Good status The general objective of the WFD is to achieve ‘good status’ for all surface waters by 2015. ‘Good status’ means the achievement of both ‘good ecological status’ and ‘good chemical status’

Good ecological status

WFD term denoting a slight deviation from ‘reference conditions’ in a water body, or the biological, chemical and physio-chemical and hydromorphological conditions associated with little or no human pressure

Glide Deeper water flowing smoothly over a river bed. Occasional larger cobbles or boulders on the bed may create some surface disturbance


Terminology Definition

Planform River channel pattern when viewed from above. This often referred to as either straight, sinuous, meandering or braided

Poaching Poaching can be a problem when cattle are wintered on grassland, particularly around gateways, feeding areas and watering points. This can lead to risks of soil erosion and compaction. Poaching can occur where the land is ‘cut-up’ through cattle moving or tramping on wet soils. This removes the vegetative cover, leaving the soil open to the elements and prone to being washed away via surface water run-off and can pollute watercourses

Pool Deeper, steadier water. Pools are usually located at bends in watercourses, and depth decreases towards the outside of a bend

Pressure The direct effect of the driver (for example, an effect that causes a change). Pressures include morphological alterations, abstraction, diffuse source pollution, point source pollution and flow regulation. In the context of the WFD a significant pressure is one that, on its own, or in combination with other pressures, would be liable to cause a failure to achieve the environmental objectives set out under Article 4

Reach A length of channel which, for example, may have a homogeneous geomorphology (river type) or restoration solution

Reference conditions

For any surface water body type, reference condition is a state in the present or in the past where there are no, or only very minor, changes to the values of the hydromorphological, physico-chemical, and biological quality elements which would be found in the absence of anthropogenic disturbance

Re-profiling The reshaping of a river bank. May be a reflection of channel modification (impact) or restoration

Riffle A stream bed accumulation of coarse alluvium linked with the scour of an upstream pool

Riparian Zone Strip of land along the top of a river bank. Plant communities along the river banks are often referred to as riparian vegetation

River Dee and Bala Lake/ Afon Dyfrdwy a Llyn Tegid SAC

The SAC extends across both English and Welsh sections of the River Dee/ Afon Dyfrdwy

River Dee (England) SSSI

The River Dee/ Afon Dyfrdwy is divided into two SSSIs. The River Dee (England) SSSI specifically refers to the English SSSI that is managed by the EA and NE

Run Quicker water, deeper than riffles and usually with a stony or rocky bed which creates a ruffled surface

Tributary A stream or river which flows into a larger river. A tributary does not flow directly into the sea

Unfavourable condition

Description of the condition of the features for which a SSSI or SAC has been designated. Unfavourable condition means that all of the targets for the mandatory attributes (population and


Terminology Definition habitat) used to assess a feature have not been met

Woody debris Woody debris are logs, sticks, branches, and other wood that falls into streams and rivers. This debris can influence the flow and the shape of the stream channel

B1867400 River Dee SSSI Restoration Management Report_March 2013_Final.doc 1

1 Introduction

1.1 The River Dee/ Afon Dyfrdwy

The River Dee is a transboundary river which flows through Wales and England. Through Wales the river is called the Afon Dyfrdwy and in England it is called the River Dee. Compared to other European rivers the flow in the River Dee/ Afon Dyfrdwy is highly regulated, however, despite this the river and its tributaries support a number of habitats and species of national conservation importance. As a result the River Dee and several of its tributaries (namely the Afon Mynach, Afon Meloch, Afon Tryweryn and Afon Ceiriog) are designated as Sites of Special Scientific Interest (SSSIs) under the Wildlife and Countryside Act 1981. The whole of the River Dee/ Afon Dyfrdwy and the aforementioned tributaries are also designated as a Special Area of Conservation (SAC) under the EU Habitats Directive. The River Dee/ Afon Dyfrdwy is notified as a SSSI for mainly for the unique transitions through a range of river habitat types from eutrophic to mesotrophic. These habitats support designated species features such as Ranunculus communities, floating water plantain Luronuim natans, Atlantic salmon Salmo salar, bullhead Cottus gobio, sea lamprey Petromyzon marinus, river lamprey lampetra fluviatilis, brook lamprey Lampetra planeri, otter Lutra lutra, club tailed dragonfly Gomphus vulgatissimus and fluvial geomorphology at Rhewl, just upstream of Llangollen and in the meandering section of the main Dee between Holt and Worthenbury and Carboniferous stratigraphy at Dee Bridge.

Figure 1.1 An otter, bullhead and Ranunculus

1.2 Why do we need to restore the SSSIs of the River Dee?

Currently the majority of the SSSIs and SAC are assessed to be in unfavourable condition, due to a number of historical and current pressures. For a number of the feature species insufficient data is currently available to sufficiently identify changing trends in populations, therefore it is difficult to ascertain the current status of these species. Surveys of Atlantic salmon, bullhead and lamprey species have used indicators such as population density and distribution to determine unfavourable condition (Hatcher and Garrett, 2008). Water Framework Directive (WFD) assessments for ecological statuses of water bodies that comprise both SSSIs have identified water pollution as a significant problem for the designated features along the entire length of the river. Particularly affected are the Afon Tryweryn and Afon Mynach, which experience high levels of the sheep dip pesticide Cypermethrin, which notably affects macro-invertebrates. The Lower Dee is also periodically affected by high nutrient levels, resulting in significant growth of water crowfoot (Ranunculus sp.) that can disrupt fish habitats and bind gravel together so tightly that spawning cannot take place (Environment


Agency, 2012). Water quality is a principal reason for some features of the site not reaching favourable status. In addition to water quality pressures, physical habitats have been identified as a reason for feature species failing to reach favourable status with patchy distribution of suitable and optimum habitat throughout the river catchment. It is therefore imperative that physical river restoration measures are considered to improve the river environment and consequently increases the sustainability of features species. The purpose of this study is to develop a restoration vision of the whole river catchment, identifying where the main pressures are and outlining restoration measures to achieve favourable condition. As the river lies within both England and Wales, a number of Statutory Bodies are involved with this project including the Environment Agency, Environment Agency Wales, Natural England and Countryside Commission for Wales (CCW). It should be noted that from 1 April 2013, Natural Resources Wales will take over the functions currently carried out by the Countryside Council for Wales, Environment Agency Wales and Forestry Commission Wales.

This study considers both recent and historic modifications to the river channel and floodplain. Modifications such as weirs, bank protection, embankments, channel realignment and riparian degradation have, in combination, led to a reduction in the diversity of natural habitats. The loss of natural habitats has reduced the potential for the catchment to support species of conservation value through the fragmentation and isolation of populations, degradation of marginal and in-channel habitat complexity. If a more naturally functioning channel and floodplain connectivity can be restored, where the impacts of past modifications are evident, then the extent of suitable habitat for wildlife should increase, with subsequent benefits for the flora and fauna that depend on them. Restoration would also help increase resilience of the river system to increasing pressures from changing resource use and climate change. More information on the geomorphological and ecological characteristics of the River Dee/ Afon Dyfrdwy and its tributaries is provided in the accompanying Technical Report.

1.3 European Directives

This and future work on the SSSIs and SAC of the River Dee/ Afon Dyfrdwy will help achieve both the objectives of the Habitats Directive and the Water Framework Directive (WFD). These pieces of European legislation aim for SAC rivers to achieve favourable condition and all rivers to achieve Good Ecological Status or Good Ecological Potential (where the water bodies are heavily modified) respectively.

What is river restoration? River restoration refers to river improvement activities that are designed to return the structure (morphology) and ecology of a river back towards a pre-disturbance (natural) condition. This can include river management activities such as complete restoration (involving in-channel works) of an existing section of channel, enhancement of an existing section of channel (such as by improved management) and/or the creation of a new section of river channel with features designed to replicate natural conditions.


Funding relating to achieving the aims of these Directives will help deliver the future conservation, enhancement and ecological restoration of rivers where feasible.

1.4 Aim and objectives of the Management Report

The aim of this Management Report is to identify river restoration measures that can help bring the SSSIs and SAC of the River Dee/Afon Dyfrdwy up to ‘favourable’ or ‘unfavourable recovering’ condition under the Habitats Directive. These options should also help the parts of the river currently failing to achieve Good Ecological Status or Potential under the WFD. This overall aim includes the following specific objectives:

1. Determine the impact of physical modification giving examples of each 2. Provide an outline restoration plan for the river on a reach specific basis 3. Identify potential delivery mechanisms

The restoration options are presented in a series of restoration plans in Section 4.2. The Management Report is intended to provide a framework for the restoration of the SSSIs and SAC of the River Dee/ Afon Dyfrdwy for the next 20 to 30 years. Flow regulation and abstraction regime have not been investigated specifically within this project but it is anticipated that the findings of this project will be complementary to other programmes of work currently being carried out by the Environment Agency. These include the review of abstraction licences potentially impacting on the River Dee and Bala Lake SAC where required changes are being implemented through the Restoring Sustainable Abstraction (RSA) programme and the investigation of WFD mitigation measures to address physical modifications associated with water storage and supply. Investigations fall into the categories ‘investigate cause of failure’, ‘investigate to confirm failure and/or impact’, ‘investigate feasible measures’ and ‘investigate nature and extent of ecological

Favourable condition Favourable condition is when the special habitats and features are in a healthy state and conserved for the future by appropriate management. Unfavourable recovery is when all necessary management measures are in place to address reasons for unfavourable conditions. If sustained, the site will recover over time. Good Ecological Status The general objective of the Water Framework Directive (WFD) is to achieve overall ‘Good Ecological Status’ for all surface waters by 2015. To be in overall ‘good’ status both ecological and chemical status must be at least ‘good’. Good Ecological Status refers to situations where the ecological characteristics show only a slight deviation from ‘reference conditions’. In such a situation the biological, chemical and physio-chemical and hydromorphological conditions are associated with limited or no human pressures. Good Ecological Potential Some water bodies have important uses which prevent them from achieving natural conditions. These are classified under the WFD as artificial or heavily modified. These water bodies have a target to achieve Good Ecological Potential, which recognises their important uses, whilst making sure ecological is protected


impact’. These investigations take into consideration that flow regulation is needed to protect water quality and drinking water supply. More information on the programme of WFD investigations can be found at http://www.environment-agency.gov.uk/research/planning/33106.aspx in the spreadsheet entitled ‘Water Framework Investigations programme detail (July 2012)’ and details of the RSA programme can be found at http://www.environment-agency.gov.uk/business/topics/water/32026.aspx.

1.5 Stakeholder involvement

The restoration plans in this management report aim to identify possible options that could be implemented along the River Dee/ Afon Dyfrdwy to improve the natural function of the river and increase the length, number and connectivity of habitats for aquatic and terrestrial wildlife. To achieve the aims of this Management Report, the Statutory Bodies (Environment Agency, Environment Agency Wales, Natural England and CCW) recognise the need for effective and positive engagement with land owners, land managers and other river users. In addition to landowners and tenants, the stakeholders engaged in the development of the restoration plans include the National Farmers Union (NFU), Country Land and Business Association (CLA), Angling Associations, Welsh Dee Trust, Wildlife Trusts, Forestry Commission, National Forest and Local Councils. This version of the Management Report has been updated to incorporate feedback on the proposed restoration options raised during consultation. The feedback was obtained during a one month online consultation that ran from 15th February 2013 to 15th March 2013 on the Environment Agency website and a day event held on 28th February 2013 at the Wild Pheasant Hotel, Llangollen. Where applicable, the feedback has been incorporated in this version of the report. Consultee comments and responses raised during the consultation event are provided in Appendix A of this report. These, and potentially other comments raised after 15th March 2013, will be held on file and used to inform future discussions with stakeholders as restoration projects are taken forward. Going forward, the Statutory Bodies will work with stakeholders to agree how best to deliver the restoration plans. Whilst some options will be able to be implemented over the next few years, other measures will take longer to organise with the landowners and interested parties. This plan should be considered as a long term restoration strategy.


2 The River Dee/ Afon Dyfrdwy SSSIs and SAC

2.1 Overview

As previously mentioned, the River Dee/ Afon Dyfrdwy have been separated into two SSSIs divided by the national boundary; the Afon Dyfrdwy (River Dee) SSSI and the River Dee (England) SSSI. The Welsh SSSI includes the upper part of the main stem Dee, Afon Mynach, Afon Meloch, Afon Tryweryn and the upper part of the River Ceiriog (except the headwaters). The English SSSI includes the lower part of the main stem Dee and the lower part of the River Ceiriog. The total length of both SSSIs is approximately 180km. The English River Dee SSSI is further divided into four units, shown on Figure 2.1. CCW has divided the SSSI into 19 managements units for both the English and Welsh sections of the SSSIs and SAC, shown on Figure 2.2. The function of this Management Report is to provide a holistic catchment wide approach to the restoration of both SSSIs. A desk study and targeted field surveys were undertaken to gain a full understanding of the geomorphological and ecological characteristics of the River Dee/ Afon Dyfrdwy and its tributaries (for more information see the accompanying Technical Report). During the geomorphological and ecological appraisal of the River Dee/ Afon Dyfrdwy and its tributaries, the river system was divided into four parts: the Upper, Middle and Lower Dee and the Afon/ River Ceiriog. Table 2-1 provides the location of the four parts of the River Dee/ Afon Dwfrdwy and relates each part with the relevant SSSI designations and CCW management units.

Table 2-1 Divisions of River Dee/ Afon Dyfrdwy SSSI//SAC

Section name Section extents Designation CCW management units

Upper Dee (Afon Mynach, Afon Meloch, Afon Tryweyrn and main stem Dee from Bala Lake to Corwen)

Headwaters and main stem Dee to Corwen


15, 16, 17, 2, 3 and upstream half of 4

Middle Dee Corwen to Overton Afon Dyfrdwy (River Dee) SSSI

Downstream half of 4, 5, 6, 7 and 8

Lower Dee Overton to Chester Afon Dyfrdwy (River Dee) SSSI and River Dee (England) SSSI (units 1, 4 and 5)

9, 10, 11, 12, 13 and 14

Afon/ River Ceiriog All of the River Ceiriog

Afon Dyfrdwy (River Dee) SSSI and River Dee (England) SSSI (unit 3)

18 and 19


Figure 2.1 River Dee (England) SSSI units


Figure 2.2 CCW management unit, English SSSI units and river divisions


2.2 Geology and land use

The source of the River Dee/ Afon Dyfrdwy is in the mountains of Snowdonia National Park. The river flows generally in an easterly direction through the steep valley sides of the Vale of Llangollen until Worthenbury. From Worthenbury it flows north through open lowland to the estuary at Chester. Chester weir demarcates the tidal limit, however tidal influences can occur as far upstream as Farndon (at the downstream end of the Dee meanders), due to freshwater backing up during high tides. The course and topography of the River Dee/ Afon Dyfrdwy have been largely influenced by glaciers. Between Bala Lake and Chester the River Dee/ Afon Dyfrdwy flows over predominantly sedimentary bedrock consisting of mudstones, sandstones and siltstones. Much of the bedrock is overlain with unconsolidated drift deposits (till) up to 100m thick and glacial sands and gravels up to 28m thick. These form important potential sources of sediment for the river today. The headwaters, Upper and Middle Dee and Afon/ River Ceiriog are all typical of upland rivers flowing across land that is predominantly used as pasture for grazing and forestry. In the Lower Dee, particularly the Cheshire Plain, the soil is more fertile and intensive dairy farming takes place. Only around 6% of the whole Dee catchment is urbanised with over 60% of the population being concentrated in Wrexham, Chester and Deeside (Environment Agency, 2010). Smaller villages are scattered throughout the Dee catchment (including Llangollen, Bangor-on-Dee and Farndon).

2.3 Channel changes and past practices

Channel change along the Dee is widespread but confined to local areas. According to Hill and Emery (2005) the most active areas in terms of historical planform change are between Bala Lake outfall and Corwen (Upper Dee) and also the Dee meanders (Lower Dee). The least active areas of historic planform change are Farndon to Chester weir (Lower Dee) and Glyndyfrdwy to Overton (Middle Dee). Analysis of aerial photographs (Gurnell, 1997) and the Hill and Emery (2005) Fluvial Audit report the meanders in the Lower Dee to be relatively stable in recent times. This is perhaps due to the effect of flow regulation. In contrast, the meanders in the Upper Dee appear to be actively migrating and changing, within the constraints of the steep valleys sides (Hill and Emery, 2005). Records and accounts (held in the British National Library) give information about the range of capital and maintenance works carried out each year from approximately 1930 to 1990. These included gravel and woody debris removal, bed and bank protection in the upper tributaries and Upper and Middle Dee. In the Lower Dee there are records of gravel removal and extensive construction of bank protection (mainly stone pitching) to prevent lateral movement, although this appears to have largely washed out now. Throughout the catchment, areas of urban settlement were protected by the construction of flood prevention schemes using embankments and walls. Some of the tributaries outside of the SSSIs and SAC were also resectioned and regraded. These capital and maintenance works are outlined in Appendix A and B of the Technical Report.


2.4 Hydrology

The hydrology of the headwater tributaries and the River Ceiriog are characterised by flashy hydrological regimes. The hydrological regime of the main stem Dee itself has been regulated for water storage and supply since the early 19th century to maintain low flows (during drier periods of the year) and reduce peak flows (during wetter periods). The purpose of increased discharge under low flows is to support water abstraction, maintain water levels in the Llangollen Canal, limit the upstream penetration of saline water in the Lower Dee during high tides and support the passage of migratory fish (Hill and Emery, 2005). The purpose of reduced peak flows is to reduce flood risk throughout the catchment. Regulation of flow and the associated removal of peak and low flow event affects the distribution of aquatic habitats and reduces the ability of the river to self regulate. The river self regulates through peak flows which flush out deposition of fine sediment, which would otherwise smother spawning beds. This in turn reduces the diversity of in-channel habitats, reducing the potential for connectivity between co-habiting life stages of key conservation species (such as salmon or lamprey) and may lead to changes in vegetation communities. Flow regulation may reduce the rate of natural recovery of the river due to the removal of peak flows. Geomorphologically important peak flows have high stream powers which result in the greatest amount of erosion. Such erosion may alter the position of river banks and sediment deposits within the channel. During peak flows the river becomes connected to the floodplain which opens up a greater area for deposition to occur out of the channel and may increase the fertility of the land. Removing peak flows may reduce maximum stream powers, limiting the degree to which the river can naturally adjust to previous channel modifications.

2.5 Ecology

The rivers of the Dee catchment are some of the best in the UK and are designated as nationally important Sites of Special Scientific Interest (SSSI). The River Dee/ Afon Dyfrdwy is notified as a SSSI for the unique transitions through a range of river types from eutrophic to mesotrophic. These habitats support characteristic species including Atlantic salmon, otter, Club-tailed dragonfly and fluvial geomorphology. The River Dee and Bala Lake are also designated as a Special Area of Conservation (SAC) as a river habitat that supports certain internationally notable aquatic plant communities, and populations of sea, river and brook lamprey, Atlantic Salmon and otter. The SAC designation is primarily for the river habitat characterised by Ranunculion fluitantis and Callitricho-Batrachion communities. Floating mats of the former of these species are characteristic in early to mid-summer. The Ranunculus beds influence riverine ecology by modifying water flow, promoting fine sediment deposition, and providing shelter and food for fish and invertebrate fauna (JNCC, 2013). In addition the River Dee/ Afon Dyfrdwy supports a number of important species including Atlantic salmon, floating water plantain, sea lamprey, brook lamprey, river lamprey, bullhead and otter. These species require a wide range of habitat types but all favour clean, well oxygenated water. Although not ubiquitous to this river system the wide range of optimal habitats required (at different life stages of each species) are present in varying extents and therefore the Dee/ Dyfrdwy retains sufficient


interconnectivity between key habitats to maintain these high value conservation species. Some of the features (e.g. club-tailed dragonfly) are naturally restricted to particular reaches where their specific habitat requirements are met, whereas others (e.g. otter) occur throughout the catchment. A number of the feature species migrate through the catchment, from the seaward end to the headwaters (and back again) to undertake spawning and juvenile development. Species undertaking migration are particularly sensitive to changes in flow, physio-chemical conditions and physical habitat. As with the club tailed dragonfly (restricted to silt deposits in the lower river) there are natural limits to migrating species, with steep headwater catchments and high energy flow types preventing egress into the headwater tributaries. Channel form and artificial obstructions pose an additional risk to migratory and resident species, isolating populations, preventing movement between habitats and increasing the risks of exploitation.

2.6 Pressures and impacts

2.6.1 Condition assessment

The River Dee/ Afon Dyfrdwy has been assessed for condition differently in England and in Wales. Three of the four English SSSI units are judged to be in unfavourable condition (Table 2-2). The condition of the Welsh SSSI has not yet been assessed on a unit basis, however many of the SSSI features are also SAC features and condition has been assessed for them (Table 2-3). From this it is presumed that most of the management units (Figure 2-2) are in unfavourable condition. Many of the reasons for unfavourable condition (Table 2-2) are also reflected in risks to achieving WFD objectives. The SSSIs and SAC are comprised of ten WFD water bodies. These ten water bodies and their WFD classifications are presented in Table 2-4 below. The Afon Tryweryn and River Dee are classified as heavily modified. The Afon Mynach, Afon Meloch and Afon Ceiriog are not designated as heavily modified. The upper tributaries (Afon Mynach, Afon Meloch and Afon Tryweryn apart from the middle section between Afon Hesgin and Afon Mynach) and the majority of the mainstem Dee are at Moderate Ecological Status/ Potential. This is principally attributed to elevated levels of copper. Other reasons for failing to achieve Good Ecological Status is the moderate status of mitigation measures (upper reaches of the Tryweryn), zinc (lower reaches of the Tryweryn), fish (upper reaches of the Dee) and invertebrates (lower reaches of the Dee). The Afon Ceiriog currently achieves Good Ecological Status.


Table 2-2 River Dee (England) SSSI units and condition assessment status

Unit and location Condition status Reason for condition status

1 – River Dee (England) From Chester weir to Farndon

Unfavourable – no change

Failing of many targets including water quality due to pollution from agriculture/runoff and water pollution discharge (phosphate), salmon, bullhead and macrophyte assessments

3 – River Ceiriog Unfavourable – no change

No change to diffuse water pollution levels and inappropriate structures such as weirs, dams and other structures

4 – Farndon – Shocklach (Within the river channel)

Unfavourable – no change

Fails water quality targets, macrophyte assessment and salmon targets

5 – Farndon- Shocklach (Fluvial geomorphological patterns/ processes and adjacent floodplain)

Favourable The river displays the necessary characteristics of a geomorphologically active river, with obvious undercutting and deposition along the length of the unit


Table 2-3 SAC features and condition status including their relevant CCW management units (KH: key habitat, KS: key species) (Source: Hatcher and Garrett, 2008)

SAC feature Condition status Key habitat (KH)/Key species (KS) and CCW management unit

Reasons for condition status

1. Watercourses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation

Unfavourable – unclassified

KH in units 2-13 and 15-19

Due to data gaps and flooding problems during last survey by Scarlett et al. (2003) the habitat distribution is unknown. Precautionary approach to assume this condition status

2. Atlantic salmon Salmo salar

Unfavourable KS in units 2-19 Fish survey (Pisces Conservation Ltd. (2007)) recorded fails in the following criteria:

• Adult run population

• All parameters of water quality

• Environmental disturbance – management objectives, sustainable exploitation

3. Floating water plantain Luronium natans

Favourable - unclassified

KS in unit 2 Partial baseline data means not possible to make trends. Records of this feature date back to 1780. No reason to suppose current operations are causing a decline in numbers

4. Sea lamprey Petromyzon marinus

Unfavourable - unclassified

KS in units 9-14 and Monitoring by APEM (2006) showed that this species did not reach the ammocoete density target. Concern over barriers to migration. Suggested that Erbistock weir marks boundary between sea lamprey and brook lamprey

5. Brook lamprey Lampetra planeri

Unfavourable – unclassified

KS in units 2-13 and 15-19

APEM (2006) monitoring showed that this species failed JNCC target. However as it is difficult to identify between Brook and River lamprey in field results may be misleading and therefore a precautionary approach is to assume that this species is in unfavourable condition

6. River lamprey Lampetra fluviatilis

Unfavourable unclassified


Same as above

7. Bullhead Cottus gobio Unfavourable - unclassified

KS in units 2-13 and 15-19.

Survey (by Pisces Conservation Ltd.(2007)) showed this species to fail due to:

• Adult population densities

• Distribution with the SAC

• Water quality parameters (Biological GQA and soluble reactive phosphorous). Due to small sample size more data is required to verify this condition


SAC feature Condition status Key habitat (KH)/Key species (KS) and CCW management unit

Reasons for condition status

8. European Otter Lutra lutra

Favourable - unclassified


Based on Phil Morgan survey (Morgan, 2004). Unclassified as no trend can be determined until further surveys take place. Otter survey of England and Wales 2009-2010 recorded evidence of otters at 93% of the 59 sites in the Dee catchment which were surveyed. Evidence was recorded at 78% of these sites during the 2002 survey

Table 2-4 WFD water body ID, name and status for the main stem Dee and its tributaries within this study (Source: Environment Agency, 2009)

Water body ID Name Overall water body status

Reason for failing to achieve GES

SSSI designation CCW management unit

GB111067051990 Afon Mynach Moderate Ecological Status

Copper – moderate Afon Dyfrdwy (River Dee) SSSI

16

GB111067051960 Afon Meloch Moderate Ecological Status


17

GB111067051980 Tryweryn – Hesgin to Llyn Celyn

Moderate Ecological Potential

Mitigation measures - moderate


15

GB111067051920 Tryweryn – Mynach to Hesgin

Good Ecological Potential

None Afon Dyfrdwy (River Dee) SSSI

15

GB111067051900 Tryweryn – Mynach confluence to Dee confluence


Copper – moderate Zinc - moderate


15

GB111067051610 Ceiriog – upstream of Teirw

Good Ecological Status

None Afon Dyfrdwy (River Dee) SSSI

18

GB111067051910 Ceiriog – Teirw to confluence with Dee

Good Ecological Status

None Afon Dyfrdwy (River Dee) SSSI and River Dee (England) SSSI (unit 3)

18-19

GB111067052240 Dee – Alwen to outlet Llyn Tegid/ Bala Lake

Good Ecological Potential

Fish – moderate* Afon Dyfrdwy (River Dee) SSSI

2-4

GB111067052060 Dee – Alwen to confluence with Ceiriog



4-7

GB111067057080 Dee – confluence with Ceiriog to Chester weir


Invertebrates - moderate

River Dee (England) SSSI (units 1, 3, 4 and 5)

7-14

* Note, water body is assessed at achieving Good Ecological Potential, all quality elements achieve good or high status apart from fish, which is assessed as moderate (quite certain)


2.6.2 Desk study

In order to identify the key morphological pressures on the River Dee/ Afon Dwfrdwy and its tributaries a review of the existing literature and data was undertaken. This included a review of the Hill and Emery (2005) Fluvial Audit of the River Dee and historical channel modification records stored in the British National Library. The full findings of the desk study are reported in Sections 3 and 4 in the Technical Report. The desk study also comprised a gap analysis to establish where data does not currently exist and to inform the selection of sites to be surveyed as part of this study. 2.6.3 Field survey

To gain a more complete picture of the condition of the physical structure (geomorphology) and ecology of the River Dee/ Afon Dwfrdwy and its tributaries, a series of spot checks and short walkover surveys were undertaken during November and December 2012. To assess the need for channel restoration, the condition of the river channel as recorded during the field surveys was compared to the characteristics of the river channel that might be expected with limited human impact. The Dee/ Dyfrdwy catchment comprise four main river types, Type II, VI, VII and VIII. The key characteristics and ecological importance of each of these river types is explained in Table 2-5. Based on the river characteristics defined for the different river types, the Afon Mynach and Afon Meloch are classified as Type VII and Type VIII, Afon Tryweryn as Type VI, the River Ceiriog as Type VI and II, and the main stem River Dee (Upper, Middle and Lower) is classified as Type II.

Table 2-5 Four river types and their key charactertistics and ecological importance of the River Dee/ Afon Dyfrdwy SSSIs and SAC (based on Mainstone, 2007)

JNCC river type River characteristics under conditions of low anthropogenic impacts

Ecological importance

Type II: Clay rivers with diverse subtrates and flow patterns

Low gradient catchment with river channels running over clay or alluvium (sometimes chalk). Stream power variable but generally low. Bed materials likely to be dominated by silts and sands with coarser gravels accumulating at riffles. Flow patterns are likely to be dominated by glide with coarser substrates underlying occasional riffles and finer materials underlying deeper pools

Woody debris accumulations would be expected to contribute to flow type variability in this river type and create refuge habitats and pools for aquatic species. Woody debris is also important for decomposer species River bed gravels or other coarse substrate provide an essential but generally scant habitat for a wide variety of invertebrate and fish species these river types

Type VI: base-rich, mesotrophic rivers in western and northern Britain, with a moderate to fast current

Catchments tend to be mid-altitude. Moderate stream gradients have substrates dominated by gravels and pebbles. Outcropping bedrock and boulders are common features creating variable flow types including step-pools, riffles and glides. Exposed side and mid-channel bars both vegetated and unvegetated are common as well as sandy margins with some vegetation Where there is a floodplain, active meandering can occur with vertical

Riparian trees are important for providing a source of woody debris, leaf litter and exposed tree root systems as submerged habitat and refuge areas for fish and invertebrates


JNCC river type River characteristics under conditions of low anthropogenic impacts

Ecological importance

cliffs and point bars Type VII: Mesotrophic upland plateau rivers

Upland catchments with underlying shale, hard limestone and hard sandstone geology. Shallow stream gradient and stable flow regime which results in finer substrates such as exposed gravel bars

Characterised by wetland edge vascular plants such as Myosotis scorpioides and Phalaris arundinacea. Invertebrates tend to be riffle-dwelling or inhabit vegetated or unvegetated gravel bars

Type VIII: Moderate-gradient sand/shale rivers below uplands

Similar to Type VII although steeper and more energetic, dominated by cobbles, boulders and bedrock

Vegetation is dominated by bryophytes (such as Rhynchostegium riparioides, Chiloscyphus polyanthus and Hygrohypnum ochraceum) with exposed bedrock and chutes ideal for a range of riffle-dwelling invertebrates

2.6.4 Key findings

The River Dee/ Afon Dyfrdwy and tributaries have been subject to a long history of modification for navigation, flood alleviation, agricultural drainage or have been straightened as a result of roads, railways or urban development. The floodplains of the main stem River Dee/ Afon Dyfrdwy and tributaries are now highly managed and intensively farmed along much of their lengths. Livestock farming dominates land use in the Upper and Middle Dee whilst a mixture of livestock and arable farming are present in the Lower Dee. The intensification of farming for crops and livestock has also led to degraded riparian zones and increased silt input to the river system from surface runoff and poaching. In addition past maintenance works such as woody debris and gravel removal have resulted in a reduction in the habitats on the main stem Dee. The most prevalent pressures on the river, except for flow regulation, are those related to land use and riparian vegetation degradation. The field results revealed that the geomorphology and ecology of the River Dee/ Afon Dyfrdwy and the upper tributaries vary along their lengths and many of the features that would be expected under natural conditions are present. On the whole, reaches along the River Dee/ Afon Dyfrdwy and its tributaries exhibit good morphology close to that which might be expected under natural circumstances and these stretches have the potential to support optimum habitats for feature species. There has been little channel modification of the headwaters. Instead the natural geomorphology of the watercourse (steep gradients and higher energy flow types) restricts the distribution of certain species. The majority of the main stem Dee and tributaries that comprise the SSSIs and SAC shows some degree of human impact (pressures) which need to be addressed to restore more natural geomorphological and ecological conditions (Table 2-6). Channelisation at the confluence of the Dee and the Tryweryn and through Chester has significantly reduced the diversity of geomorphology and the channel is devoid of the typical features expected. As a result there is a reduction in optimum habitats for ecological features. However, some reaches of the river channel have adjusted or are in the process of adjusting and recovering following disturbance. Those sections which are recovering (e.g. Dee meanders) now exhibit good morphology (physical form and function) and associated habitat diversity within the river channel. The development of depositional features through natural channel adjustment provides suitable spawning and juvenile habitat for fish and lamprey.


Table 2-6 Pressures caused by human activity and their impact on the River Dee SSSI

Feature Description of impact Consequences Example

Degraded riparian vegetation Change in the type of terrestrial vegetation along the river corridor away from that characteristic of the river type, due to land use. This may include complete removal due to ploughing or reduction in variety and density of vegetation due to grazing by livestock

• Increases the amount of surface runoff reaching the channel which may supply high loads of fine sediment or dissolved nutrients

• Increases the vulnerability of the river corridor to suffer erosion (soil loss) during floods where the ground is bare

• Makes the banks more vulnerable to erosion (e.g. lack of roots binding the banks)

• Silt recorded in spawning habitats in the Ceiriog, for example, is mainly from terrestrial runoff (Walling, 2008). A thin riparian buffer zone acts as a poor filter for such runoff

• The stonefly requires clean in-channel substrate to survive, therefore accelerated silt input from riparian zone degradation will detrimentally affect this species.

• Lack of riparian vegetation reduces cover for fish from bird predation, and habitat for fly-life, which is fish food source.

Afon Ceiriog (CEI00007)

Riparian zone

Lack of trees Some sections of river, which may (or may not) have generally good riparian vegetation cover due to low land use pressures lack trees due to earlier removal

• May make the banks more vulnerable to erosion (e.g. lack of roots binding the banks)

• Lack of a supply of woody debris which would, if present, vary flow and sediment deposition patterns and associated habitat benefits (particularly beneficial for Type II and VI, Table 2-5)

• Lack of channel shading increases summer water temperatures

• Lack of cover for fish and otter

• Reduced organic input from leaf fall may reduce habitat suitability for lamprey ammocoetes

• Reduced habitat suitability for club-tailed dragonfly (adult lifestage)

• Increased macrophyte and algal growth in high nutrient reaches

• Reduced foraging and nesting/roosting opportunities for birds and bats

Upper Dee – near Llandrillo (DEE001)



Degraded bank face vegetation Change in the type of bank face vegetation along the river corridor away from that characteristic of the river type (see Table 2-5), due to land use or channel modification. This may include damage by livestock or modifications such as channel straightening, bank protection and channel maintenance

• Reduces the habitat variability along the banks

• Lack of cover and channel shading for fish and otter

• Reduces feeding opportunities for salmonids (aerial invertebrates)

• Exposed makes the banks more vulnerable to erosion (lack of roots binding the banks)

Lower Dee – Dee meanders (DEE002)

Banks

Accelerated bank erosion Increase in bank erosion due to land use or channel modification. This may include damage by livestock or modifications such as channel straightening, bank protection and channel maintenance

• Increases the supply of sediment to the channel, which can lead to increased siltation of coarse substrates used for spawning

• Loss of bank side cover

Upper Dee – Corwen (DEE001SP)



Lack of morphological diversity due to channel straightening and bank protection

• Reduces the habitat variability along the banks

• Lack of cover for fish

• Reduced invertebrate community resulting in reduced food supply for fish

• Reduced deposition may result in a reduction in spawning habitat

• Loss of habitat connectivity (e.g spawning habitat may be disconnected from juvenile habitat)

• Straightened channels typically have a higher stream energy than would be anticipated naturally and are often incised (through erosion), thereby increasing the risk of bank erosion and embankment failure

• The club-tailed dragonfly requires sparsely vegetated banks to haul out on when it is emerging from its exuvium (cast off skin). Areas with bank protection will prevent this species from doing this.

Afon Ceiriog (CEI002SP)

Bed Lack of morphological diversity due to channel straightening

Channel deepening (dredging) and re-shaping associated with straightening to improve water conveyance and land drainage can lead to a uniform bed topography with little variation in composition (sediment type)

• Reduces the range of habitats which would be expected to be characteristic of the river type such as those associated with different water depths and flow velocities (see Table 2-5). For example, shallow areas typical of gravel riffles are often damaged or removed by dredging

• Often creates long slow glides where the channel becomes choked by emergent vegetation

• Straightened channels typically have a higher stream energy than would be anticipated naturally and are often incised (through erosion), leading to an armoured bed sometimes composed of large cobbles rather than gravels

• Reduced habitat suitability for Ranunculus community

• Reduced habitat suitability for bullhead.

• Higher flows in trapezoidal channels are particularly hostile to fish (especially fry) and invertebrates, causing loss or fragmentation of localised populations, especially where refuges

Bala Lake outflow (TRY001SP)



are missing (fallen trees and backwater features)

• Reduced spawning habitat for salmonids, lampreys and other coarse fish (e.g. barbel, chub and dace)

• Certain invertebrate species rely on silty substrates (club-tailed dragonfly, the weevil) or gravel substrates (the stonefly) which may be washed out in artificially straightened sections.

Planform Lack of morphological diversity due to straightening

The realignment of the river channel into a straighter course is often associated with land use or attempts to improve flow conveyance

• Reduces the variation in flow patterns associated with sinuous channels such as fast and slow areas and secondary circulations. This reduces the range of habitats associated with different flow velocities (see Table 2-5)

• Straight channels also tend to have uniform bank profiles as flow is generally parallel to the bank and this limits the occurrence of variations associated with local areas of scour/erosion

• Higher flows in trapezoidal channels are particularly hostile to fish (especially fry) and invertebrates, causing loss or fragmentation of localised populations, especially where refuges are missing (fallen trees and backwater features)

• Reduced spawning habitat for salmonids, lampreys and other lithophilous fish (e.g. barbel, chub and dace)

• Straightened channels typically have a higher stream energy than would be anticipated naturally and are often incised (through erosion), thereby increasing the risk of bank erosion and embankment failure

Afon Ceiriog (CEI002SP)



Lack of floodplain connectivity due to embankments

Creating embankments along the river bank tops can increase the amount of water that can be contained in the channel before the floodplain is inundated

• Reduction in the occurrence of floodplain inundation means that fine sediment, which would otherwise be deposited in the floodplain, is deposited within the channel, this can increase siltation

• Embankments may be subject to sudden breaches, which can cause erosion of the land surface on the floodplain beyond

• If embankments are over-topped flow can become trapped behind the embankments and increase the duration of floodplain inundation

• This leads to reductions in the effectiveness of sediment transfer thus increasing sedimentation and channel vegetation, causing choking during summer low flows and poor oxygenation

Lower Dee – Dee meanders (DEE002)

Flow

Impounded flow

Weirs impound the river and increase water levels upstream (to the level of the weir crest) which may cause ponding for some distance upstream where the channel gradient is low

• Reduces the variation in flow depth and velocity leading to long slow deep glides. This reduces the range of habitats associated with different flow velocities and water depths (see Table 2-5)

• Reduction in oxygen in the water column increasing turbidity (suspended solids)

• Can also provide suitable habitats for some species (e.g. floating water-plantain, lamprey ammoecoetes)

• Weirs may prevent, or delay movement into the upper catchment of migratory species, affecting spawning success, increasing predation/ exploitation and reducing conditions of individuals

Erbistock Weir (DEE007SP)


3 Potential solutions

3.1 Selecting restoration solutions

The majority of surveyed reaches in the Dee/ Dyfrdwy catchment show signs of good or recovering morphology. This is perhaps a response to the reduced channel maintenance relative to that carried out in the past. Reaches where morphology was recovering included the following adjustments:

• Increased flow and habitat diversity associated with the accumulation of woody debris (which would have previously been removed)

• The active erosion and washing away of bank protection (Dee meanders and in the Upper Dee near Corwen)

• Bank retreat into the embankment through fluvial erosion (prominent at the Dee meanders)

• Narrowing of the channel width through the deposition of sediment and the formation of berms along the channel margins (prominent at the Dee meanders).

The adjustment towards natural channel morphology is significant throughout the Dee/ Dyfrdwy catchment and demonstrates that the river is capable of recovering with minimal or no intervention. Secondly it provides an indication as to the type of restoration actions which are likely to be successful. In order to deliver optimal river channel processes and form, it would be necessary to both improve the morphology of the river channel and also address the impact of land use pressures on the floodplain. Ideally this would involve removing all embankments to allow improved floodplain connectivity and reduced grazing densities to allow a variety of habitats to establish along the riparian corridor. Reduced grazing densities particularly those of cattle would also reduce fine sediment input derived from poaching. This would not preclude the use of the floodplain for agriculture as grazing of lower intensity would be desirable to help maintain different habitats that are important for certain SSSI/ SAC features (e.g. club tailed dragonfly). This would require a significant shift from current farming systems. The floodplain would still be managed but in a way that would deliver optimum conditions for the SSSI/ SAC features. Full restoration of the floodplain is a long-term aspiration. However, the floodplain is regarded as an important part of the existing farmed landscape, containing productive agricultural land. As such, widespread land use change is unlikely to be feasible in the short or even medium term. In recognition of this, when selecting river restoration solutions, emphasis has been placed on the identification of measures that would bring improvements to the river channel through channel restoration and/or improvements to the river corridor. Such measure, which could be implemented more easily would address the pressures affecting the riparian and bank vegetation and those affecting the morphology of the channel (banks and bed), which have consequences for flow (Table 2-6).

3.2 Meeting WFD objectives

By developing restoration measures that help to achieve ‘favourable condition’ of the Habitats Directive and Wildlife and Countryside Act (1981), the objectives of the WFD would be met. Improving the morphology of the river channel and addressing


the impacts of land use pressures on the floodplain would help achieve and maintain Good Ecological Status (or Potential if Heavily Modified) and therefore would not cause a deterioration in the status of the water body.

3.3 Creating a restoration vision

Combining knowledge about the general characteristics that are expected of each river type within the Dee catchment (Table 2-5) with observations regarding the geomorphological and ecological characteristics, allows visions for restoration of rivers in the Dee SSSI/SAC to be produced. These give blueprints on which to base site specific restoration activities. The restoration visions for the watercourses within the River Dee/ Afon Dyfrdwy SSSIs and SAC are found on the next three pages. Images of good habitat that may be delivered via the various restoration measures are presented in Section 3.6. Contemporary river characteristics for each of the watercourses, including images of existing good habitat, are provided in Section 5 of the accompanying Technical Report.


Afon Tryweryn River Type VIII and VI (see Table 2-5)

Overview: This are typical upland headwater tributaries of a British river. Predominantly Type VIII river type in the upper reaches where gradient is steep, followed by Type VI in the mid to lower reaches.

Flow types: Cascades in upper reaches, runs and glides in mid to lower reaches.

Bed and bank sediments: Bed and banks comprised of bedrock and glacial boulders in upper reaches. In mid-lower reaches be and banks comprised of glacial deposits (including till and cobbles/ boulders). Some sand and gravel deposits.

Sediment transport characteristics: Predominantly a transfer river from Llyn Celyn to Dee/ Dyfrdwy carrying sediment from the upper reaches to the lower reaches. Very little erosion in the upper reaches and some localised erosion and deposits in the mid-lower reaches where river flows over glacial till.

Planform: River generally sinuous, confined in the upper reaches by a valley sides. This sinuosity is possibly inherited from former times when vegetation cover was lower and runoff higher. Evidence of secondary channels in places where the river is more active.

In-channel vegetation: Emergent reeds/sedges/rushes, exposed tree roots and large woody debris.

Bank vegetation: Trees which are possibly the last vestiges of a wooded post-glacial landscape and simple communities, consisting of grass and shrubs.

Ecology/Habitat suitability:

• Good otter habitat with extensive foraging and lay-up sites

• Channel, substrate and flow diversity offer suitable spawning and juvenile habitats for salmonid fishes and deeper sections for adults. Optimum spawning habitat where there lot of gravel spawning grounds. Naturally constrained in upper catchment by high flows and steep gradients limiting optimal spawning habitat

• Extensive habitat present suitable for Ranunculus communities


Afon Mynach (CCW unit 16) and Afon Meloch (CCW unit 17) River Types VII and VIII (see Table 2-5)

River Ceiriog/ Afon Ceiriog: (CCW units 18 and 19/ English SSSI unit 3) River Types II and VI (See Table 2-5)

Overview: These are typical upland headwater tributaries of a British river. Predominantly type VIII river type alternating between inactive tree-lined gravelly river, inactive rock bound with tree line. These tributaries become river type VII in the lower reaches where gradient lessens.

Flow types: Fast runs and cascades, step-pool sequences.

Bed and bank sediments: Bedrock to glacial deposits (including till and cobbles/ boulders). Also a high variety of finer sediments ranging from discrete sand/silt deposits to fine and coarser gravel. Erosion and deposition into side and point bars is frequent.

Sediment transport characteristics: Active erosion and sediment deposition occur in the upper reaches. Little evidence of deposition except in localised areas behind boulders.

Planform: Confined irregular meanders in places but rivers generally have a sinuous planform. This sinuosity is possibly inherited from former times when vegetation cover was lower and runoff higher. Evidence of secondary channels in places where the river is more active.

In-channel vegetation: Emergent reeds/sedges/rushes, exposed tree roots and large woody debris.

Bank vegetation: Trees which are possibly the last vestiges of a wooded post-glacial landscape and simple communities, consisting of grass and shrubs.


• Good otter habitat with extensive foraging and lay-up sites

• Channel, substrate and flow diversity offer suitable spawning and juvenile habitats for salmonid fishes and deeper sections for adults. Optimum spawning habitat where there lot of gravel spawning grounds. Naturally constrained in upper catchment by high flows and steep gradients limiting optimal spawning habitat

• Extensive habitat present suitable for Ranunculus communities

Overview: Winding channel, predominantly Type VI river, confined by glacial valley sides. Channel alternates between active and inactive sections and bed material is predominantly cobbles and boulders, with bedrock in places. In the lower reaches, where the Ceiriog meets the main stem Dee floodplain more deposition occurs with glide flow typical of Type II rivers. Flow types: Run for the majority of the river, but with riffles, pools and glides. There are also areas of rapids where there are large glacial boulders and bedrock outcrops in the channel.

Bed and bank sediments: Bedrock to glacial deposits (including till and cobbles/ boulders). Bed is predominantly comprised of cobbles. Cobble side and point bars are common along most of the Ceiriog. In the lower reaches, near the confluence with the Dee/ Dyfrdwy the bed is comprised of a mixture of fine sediments and cobbles. Banks are generally comprised of cohesive earth (silt and sand).

Sediment transport characteristics: The upper reaches of the Ceiriog are typical of Type VI rivers. Sediment is generally transported from the upper reaches into the lower reaches, although cobble/gravel side and point bars are common throughout. In the lower reaches of the Ceiriog there are a high proportion of deposits comprised of fine sediment such as sand and silts and a braided section with significant amounts of large woody debris.

Planform: Winding planform alternating between active and inactive sections. Becomes braided in the lower reaches where fine sediment has been deposited and mid channel islands have formed, some with mature broadleaf trees.

In channel vegetation: Extensive exposed tree roots and large woody debris throughout. Moss and lichens also present in most parts.

Bank vegetation: Largely tree-lined or with wooded areas, mainly deciduous.


• Extensive habitats present suitable for otter (exposed roots, lay up sites, woodland/vegetated banks). Evidence of badger

• Riffles and runs offer suitable spawning and juvenile habitat for salmon, predominantly in the lower reaches where there is greater flow and substrate diversity and habitats are well connected. Silt/sand substrate for larvae of lamprey species. Areas of protected refuges and overhanging vegetation

• Some habitat present suitable for Ranunculus communities


Upper/Middle Dee: CCW units 2,3,4,5,6,7,8 (English unit 3) River Type II, VI and VII (see Table 2-5)

Lower Dee: CCW units 10/ 11 (English SSSI units 4/5) and 12/13(English SSSI unit 1) River Type II (See Table 2-5)

Overview: Generally a low gradient river with confined meandering due to steep glacial valley sides of the Upper Dee and Middle Dee. Particularly narrow valley and steeper gradient at the Vale of Llangollen with bedrock outcrops in channel.

Flow types: Glides and runs. Cascades at Llangollen.

Sediment transport characteristics: Erosion is more widespread than deposition. Erosion is mainly a function of fluvial action or geotechnical failure. Deposition occurs mainly at point locations and there are a few mid-channel bars that are vegetated. Cobble bed, with coarse gravel deposits and earth (sand and silt) bank material.

Planform: Confined meandering due to steep glacial valley sides of the Upper Dee and Middle Dee. Particularly narrow in Vale of Llangollen where gradient steepens.

In-channel vegetation: Marginal vegetation comprises of emergent reeds and grass. There is also the occasional mid-channel bar that is vegetated with grasses/reeds.

Bank vegetation: Mainly uniform with grass, however where there are trees, these form a thin tree-line along the river bank. Proportionally a very small riparian buffer strip, but they prevent livestock from entering channel and causing erosion through poaching.


• Bankside woodlands offer suitable habitats for riparian mammals, with suitable exposed root systems and cover

• Salmonids observed in the river. Variation in channel habitats is suitable for fish species with runs, riffles and pools present in certain locations. Silt is present in pools and gravel/cobbles evident on inside of bends. Macrophytes offering fish refuges are present.

• Some habitat present suitable for Ranunculus communities

• Suitable for floating water-plantain below Bala outfall

Overview: Predominant river type II. Unconfined channel with an extensive alluvial floodplain and evidence of historical migration of channels. Stream power variable but generally low. Flow regulation reduces stream power and the ability of the river to migrate laterally.

Flow types: Predominantly deep slow flowing sections (pools and glides) with some shallow fast flowing sections (riffles and runs).

Sediment transport characteristics: transport appears to be predominantly clay, silt and fine sand (in suspension) although there may be some limited gravel bedload transport. River under natural conditions would deposit overbank on the adjacent floodplain.

Planform: meandering planform with potential to migrate laterally, although with flow regulation such channel adjustments are now likely to be very localised and occur much less frequently.

In channel vegetation: Locally reeds and rushes colonising the berms. Occasional mid-channel islands with trees.

Bank vegetation: would be trees and woody debris in the channel (historically removed as part of maintenance programmes).


• The form of the river creates a range of substrate and flow conditions suitable for adult salmon and lamprey ammocoetes. Side pools offer refuge areas for fish. Limited opportunity for spawning on key species due to a lack of coarse substrates and is likely to be a transitional reach for adults migrating into the headwaters

• Limited habitat present suitable for both Ranunculus communities and floating water plantain

• Bank side vegetation provides shade and cover to channel and acts as buffer strip

• Riparian woodland provides habitat suitable for riparian mammals, including badgers


3.4 ‘Room for the river’ approach

Potential restoration measures for the Dee/ Dyfrdwy have been suggested based on the ‘Room for the river’ approach. Room for the river type approaches to flood and erosion risk management and habitat restoration are increasingly being used across continental Europe, including a national programme in Holland, and on powerful rivers such as in the Rhine, Meuse, Danube and Loire, primarily as a way to manage flood risk. The ‘Room for the River approach takes into account the following:

• Dynamic fluvial systems such as that of the Dee/ Dyfrdwy are often unable to adapt naturally to changes in rainfall because they are constrained by traditional flood defence structures. Climate change is likely to mean more intensive rainfall, resulting in increased river flooding and changes in patterns of erosion. Traditional flood management solutions will continue to have a key role but alone may not always be effective or sustainable in the face of increasing flood and erosion risk over the next century, as acknowledged by the Government’s strategy “Making Space for Water” and the Pitt Review

• The risks caused by the historic and current management of mobile rivers, and a potential “room for the river”, or “making space for water” restoration approach is illustrated in Figure 3.1. Where critical infrastructure is a constraint, a similar “erodible corridor” approach may be taken. The erodible corridor concept “consists of defining a corridor in the alluvial floodplain, within which decision-makers will not seek to control erosion using engineered protections. At its simplest the concepts tries to balance the environmental benefits of allowing the river to move freely (within the corridor), and allowing sedimentary processes to occur and the economic benefits derived from protecting property and infrastructure (outside the corridor).


Figure 3.1 Risks relating to embankment and reinforcement on mobile rivers (top), and potential benefits of restoration and making room for the river (bottom)

3.5 Types of restoration

Restoration measures to restore the river channel to the condition described in the restoration visions (Section 3.2), have been categorised into riparian zone restoration and channel restoration/rehabilitation. Riparian zone restoration is required extensively throughout the River Dee/Afon Dyfrdwy catchment and channel restoration/rehabilitation is confined to local areas as river morphology is judged largely to be in favourable condition throughout the catchment.


The restoration measures have been further classified into four categories based on the degree of intervention needed, have each been assigned a colour code (Table 3-1). These categories are as follows: 1. Significant channel restoration - where the river has been extensively

modified by major structures such as weirs, channel straightening and extensive lengths of bank reinforcement

2. Assistance of natural channel recovery - where the river has started to recover a natural morphology, or displays the ability to recover, to past channel modifications, but the ability of the river to adjust fully or within a short time scale is considered unlikely without human intervention. There is typically less disturbance to the river in the short term compared to ‘significant channel restoration’

3. Natural recovery (no active restoration) - where the river channel is actively recovering a natural morphology from past channel modification. Natural fluvial processes are altering the channel bed and banks and improved habitats are developing. Optimal channel morphology is considered likely to develop without human intervention

4. Riparian zone management (including tree planting and woody debris installation) - where riparian zone is degraded or where invasive species are growing. Where riparian zone management is recommended, tree planting and reduced grazing pressure are the principal measures intended for implementation. Where such measures are not possible, woody debris installation should be considered.

Riparian zone restoration measures

• Improve riparian zone to reduce accelerated sediment supply, to provide more shade to the channel to benefit fish and to provide the means for large woody debris accumulation downstream which will enhance riverine habitats and flow types

• Increasing riparian vegetation would also enhance allocthonous organic input which may benefit larval lampreys

Channel restoration/rehabilitation measures

• Remove hard bank protection to allow natural channel adjustment

• Removing or improving weirs that present barriers to fish passage

• Remove embankments where it does not conflict with the CFMP Policy Unit and WFD Mitigation Measures Assessments to restore floodplain connectivity and function

• Promote natural channel adjustment and allow it to continue where present (including deterioration of bank protection and erosion of embankments)

• Consider re-establishing sediment sinks in straightened reaches of the tributaries

• Reduce or cease channel maintenance


Table 3-1 Reach scale and restoration option classification

Category Colour code Description

Significant channel restoration

Red Opportunities for weir removal, weir improvement, or the removal of extensive bank reinforcement. Also to realign or re-meander sections

Assisted natural channel recovery

Orange Removal of minor channel structures (localised or short sections), such as bank reinforcement and embankments

Natural recovery Yellow The channel is currently adjusting towards favourable condition and no intervention is required or very minor improvement like riparian zone replenishment could be implemented

Riparian Zone Management

Blue The geomorphological processes are optimal, however the riparian zone could be improved with fencing, buffer strips and/or planting and tree management and installation of woody debris

The River Dee/ Afon Dyfrdwy and its tributaries flow through a number of urban areas. Through these reaches the river is constrained by development and infrastructure and these areas are considered as high flood risk. These reaches therefore have not been considered in the restoration plans. Those reaches in ‘optimal’ condition (with no or very few modifications) are acknowledged to not need restoration. However these reaches require conservation and protection from degradation and should adopt the following guiding principles:

• Conserve the existing riparian and river bank vegetation;

• Look for opportunities to improve the width, density, composition of the riparian zone;

• Retain woody debris within the channel (unless it poses a significant flood risk to buildings or infrastructure);

• Do not modify the river channel (e.g. by dredging or bank reinforcement);

• Ensure that, if new land drainage ditches are excavated, or old ones restored, these are not routed to directly discharge into the river but are routed into an area of wetland or wet woodland to ensure that this water is filtered before entering the channel.

These principles should be applied to the whole river (in addition to the specific proposals).

3.6 Descriptions of the restoration measures

The following pages describe the range of measures that could be implemented to enhance or restore the morphology of the SSSIs and SAC so that the channel morphology is consistent with favourable condition. 3.6.1 Riparian zone restoration

Using aerial photographs, areas with an absence of tree cover on the river banks were identified and mapped using GIS. These included areas were the tree line was absent, isolated/scattered or fragmented. Using the Hill and Emery (2005) Fluvial Audit areas of poaching were also mapped on GIS and reaches affected by both lack of tree cover and poaching should be prioritised for riparian management. Restoring the riparian zone would bring multiple benefits by providing:


• A buffer separating agricultural land from the river channel, which can filter diffuse pollution from runoff and remove dissolved nutrients from water moving through subsurface

• An increase in resistance to erosion by binding surface soils and preventing the loss of fine sediment into the watercourse and slow the rate of erosion of banktops

• A source of woody debris and leaf detritus into the channel therefore increasing habitat diversity and complexity through the provision of cover and spawning habitats

• Cover, shelter and shade for both mammals, fish and invertebrates

• Increase channel shading to minimise macrophyte and algal growth therefore maintaining high dissolved oxygen levels. Shading reduces watercourses from heating up in summer, which in turn affects spawning of features species, dissolved oxygen concentrations and physiochemical condition.

The ideal, best practice, width of the riparian zone would be between 12 and 24 metres. However, this is a guide and there will be a need for flexibility as to the extent of the riparian zone that can be restored. The degree to which the riparian zone can be restored will therefore vary along the river. 3.6.2 Channel restoration/ rehabilitation

Four types classifications of channel restoration/ rehabilitation measures have been identified for the River Dee/ Afon Dyfrdwy, based on an assessment of the main pressures on SSSI and SAC features within the catchment. These classifications of measures are:

• Retreat of the bank into the embankments and/ or breach embankmentl

• Re-alignment to a more natural course

• Weir removal

• Bank structure removal. (a) Retreat of banks into the embankments and/ or embankment breaching

Aerial imagery and information sources including the Hill and Emery (2005) Fluvial Audit show extensive lengths of embankment along one or both banks of the main stem River Dee/ Afon Dyfrdwy. Some of these run close to the channel edge, whilst others are set back. Some have been built to protect urban or agricultural land from flooding and this is supported in several instances by the improvement and maintenance works records obtained at the British National Library (see Technical Report, Appendix A and B). Extensive lengths of disused railway ‘embankment’ have also been mapped in the Hill and Emery (2005) Fluvial Audit as embankments, particularly along the Upper and Middle Dee between Bala and Carrog. In some locations bank protection coincides with embanked lengths, although this is not common. During the walkover survey of the Dee meanders several embankments were observed to have eroded away, been breached or to be close to breaching as a result of channel migration. In terms of the river function the principal reason for allowing embankments to fail or breach (including physically removing some lengths of embankment) would be to reconnect the channel to the floodplain. Lateral connectivity is also recognised within the Water Framework Directive. This would allow fine sediment to be more naturally distributed across a floodplain rather than being deposited within an


embanked channel. It is also recognised that there is a considerable volume of literature (particularly for estuarine environments) concerning benefits for bird, fish and invertebrate life by allowing embankments to naturally fail. A number of criteria have been used to select possible sites:

1. Avoidance of high flood risk areas. In line with the Dee CMFP removal of embankments is not recommended (as part of this project) for higher risk areas for flooding except where they exist solely to protect agricultural land

2. Avoidance of modification of railway embankments. Although the railway is disused alongside some of the Dee Valley it is assumed that breaching of the embankments would have little additional effect as they already have pathways for floodwaters beneath them (bridges, culverts etc)

3. Selection of sites where breaching has already occurred (Note, this criteria has only been assessed for the Dee meanders and Farndon reaches walked in November/December 2012)

4. Locations with continuous embankments close to the channel edge along both sides of the floodplain. This is because ‘dual embankments cut-off the entire floodplain, thereby eliminating over-bank deposition. Breaching of one or both embankments is likely to be beneficial

5. Locations higher up in the catchment are likely to help eliminate fine silt from a longer length of the main stem Dee. Breaching an embankment in the tidally influenced Farndon reaches would arguably have less effect than a project in the Upper Dee.

(b) Realignment to a more natural course

From aerial photographs and OS maps there does not appear have been extensive straightening in the River Dee/ Afon Dyfrdwy SSSIs and SAC. The most extensive straightened sections identified are those at the Bala Lake Scheme (Upper Dee and Afon Tryweryn) and where the river flows through settlements such as Farndon and Chester (Lower Dee). Realignment of the river at such locations is largely infeasible as it would conflict with the objectives CFMP by increasing the risk of flooding in urban areas. At Bala Lake, the river has been straightened in order to accommodate the delivery of public water supply and therefore it would also be infeasible to select this location for restoration to a more natural river course. There may be reduced tendency of the artificially straightened lengths of the main stem Dee to recover their sinuosity naturally due to the impacts of flow regulation (in particular a reduced frequency of peak flows). A more sinuous or meandering planform on a section of river that has previously been straightened could result in the improved deposition of gravels (increasing the availability of salmonid spawning and juvenile habitats) and increased diversity in flow and substrate types. Improving flow diversity will lead to the development of different meso habitats, increasing the number of ecological niche available to both flora and fauna. Of the feature species designated within the SSSI/SAC bullhead, lamprey and salmon all require a high degree of connectivity between spawning, juvenile and adolescent life stages. Any increase therefore in the distribution and spatial linkages will improve the sustainability of the feature species. Site selection for realignment options are chosen where greatest ecological gains can be made, for example increased river sinuosity will improve the deposition of gravels, or connect to otherwise discrete habitats. Improving habitat diversity, and linking otherwise isolated communities has the potential for significant ecological benefit. Several potential locations have been identified on the key tributaries. The


options are either to allow natural recovery or to intervene. For many of the identified tributary lengths it is suggested that intervention may be necessary because natural recovery of any significance could take many decades beyond the 20-30 year vision given in this Management Report due to the relatively low slopes across the Dee floodplain. Also several of the reaches have significantly incised probably due to erosion occurring after straightening and this would tend to inhibit natural recovery without additional intervention to re-raise the bed. Feasibility of the options should be determined at a subsequent stage. (c) Weir removal

Using aerial photographs, OS maps, Jacobs (2009) study and observations from the November/December 2012 surveys, all major weirs (causing significant ponding upstream) and minor weirs (limited ponding upstream) have been mapped throughout the entire River Dee/ Afon Dyfrdwy catchment. Some of these present significant barriers to upstream migration of lampreys and other fish. Where weirs do not form complete obstruction to migrations the structure may, under certain flow conditions delay migration into the upper catchment, increasing predation or exploitation of that species or leading to deterioration in condition of the species and consequently reduce spawning success. Many of the weirs recorded still have active purposes such as the Horseshoe Falls, which feeds the Llangollen Canal and Manley Hall gauging weir, used to provide river flow data. As such there are constraints to the modification or removal of these structures. Other weirs are relics of past industries and are no longer being used. The larger structures are fitted with fish passes to allow the ascension of salmonids however assessment is needed to determine whether these passes assist the passage of lamprey into the upper catchment. Removal of weirs not only allows upstream migration of fish, it should also allow the development of more varied flow types and habitats upstream thus increasing the suitability for SAC features such as Ranunculus and other macrophytes. Weir removal or modification may also improve the connectivity between habitats and discrete populations that are currently isolated. This may also benefit species that do not undertake catchment wide migrations but which move between optimum spawning and juvenile habitats (such as bullhead and brook lamprey). At this stage no feasibility study has been carried out on the removal of each of the weirs; they have simply been mapped to signify where there are potential barriers or obstructions to fish and lamprey migration and consequently affecting the SSSIs and SAC condition. (d) Bank protection removal

Aerial photographs, Hill and Emery (2005) Fluvial Audit and November/ December 2012 site surveys show localised lengths of bank protection on the River Dee/ Afon Dyfrdwy and its tributaries. They have been placed to protect roads, embankments and urban areas from channel migration and flooding. The improvement and maintenance works records obtained at the British Library for this project (see Technical Report, Appendices A and B) provide evidence of bank protection works. Bank protection has been washed away in places, showing that the river is recovering from past works in the absence of ongoing maintenance (e.g. in the Dee meanders). Allowing bank protection to continue to fail or to be physically removed would allow the re-formation of a more natural bank profile, providing more varied marginal habitat.


A number of criteria have been used to select possible sites for bank protection removal:

• Avoidance of towns and villages and individual properties protected from erosion. As bank protection may be associated with flood defences these must be retained (albeit if replacement becomes necessary then softer forms of bank protection might be an effective replacement)

• Avoidance of bank protection measures adjacent to infrastructure such as roads

• Removal of bank protection in the Middle Dee and Lower Dee from confluence with the River Ceiriog to confluence with the Clywedog which includes the Dee Meanders SSSI. The Environment Agency vision in the Dee CFMP is reduced reliance and expenditure on agricultural defences over time, using a risk based approach. Removal of bank protection along this section (where it is directly associated with agricultural embankments) may therefore present fewer obstacles

• Selection of sites where bank protection has already partially failed (NB. This criteria has only been assessed for the Shocklach and Farndon reaches walked in November 2012)

• Locations with continuous bank protection along both sides of the floodplain. This is because in effect through these reaches there is little or no marginal habitat.


Riparian zone management Category: Riparian zone management

Description of actions:

Riparian zone management can involve a range of actions that allow a mosaic of different habitats to develop along the river

The intention is not to create an entirely wooded corridor but to create a more varied corridor where land use pressure is reduced

Actions could include combinations of the following:

• Providing a strip of species rich grassland parallel to the channel which is cut periodically

• Creating areas of species rich grassland in between meanders to create a riparian corridor

• Planting of suitable species along banks parallel to the channel where the river is straighter

• Planting clumps of vegetation between meanders to create a wider corridor of vegetation

• Fencing areas of river bank (ideally 12m behind the bank top, this is a guideline) to reduce livestock access and allow existing vegetation to fully establish (appropriate management of vegetation within fence line would be required)

• Allowing periodic summer grazing by livestock to reduce undesirable species and prevent over-shading. Light grazing with appropriate stocking levels at the right time of the year, possibly controlled by temporary electric fencing, can improve vegetation structure and niche habitat structure. Any planted trees would need protection until mature

• If grazing is not possible, alternative forms of vegetation management could be undertaken such as rotational mowing, occasional thinning out, pollarding or coppicing of trees

Illustration:

Riparian corridor of native mixed trees and shorter vegetation - parallel to straighter channel (foreground) or creating a corridor along meandering sections (in distance)

Potential benefits:

• Helps concentrate any siltation along the channel margins and in areas of slow flow such as pools and backwaters

• Improves water quality by acting as a filtration system for run-off (e.g. phosphorus) and restricting access of livestock to the bank and river channel

• Creation of a source of woody debris to provide morphological diversity through small-scale erosion and sediment deposition in the channel, creating a variety of habitat niches for various aquatic species

• Bank-side vegetation creates diversity in shading and cover- important for juvenile fish

• Bank side trees regulate water temperature, this may offer a significant benefit in future by off-setting the impact of climate change

• Reduced rates of bank erosion due to the increase in vegetation cover

• Bank-side trees and dense vegetation can provide habitat for otters and bats

Riparian corridor – strip of land parallel to the river


Examples:

Example of a good existing riparian zone with mixed vegetation creating areas of cover and shade along the River Dee near Manley Hall weir (left) and area of degraded riparian zone on the River Ceiriog near Pentre (right):

Example of a good corridor of riparian vegetation (viewed from the air) upstream (taken from River Mease SSSI/SAC Restoration Plan, Jacobs 2012). Note that the corridor contains a range of different vegetation types and densities and also varies in width

Note how this contrasts with an area of more intensive land use right up to the river bank:

Potential constraints

• Creating a riparian corridor will require a change in land management, it will therefore be necessary to provide appropriate incentives and funding (see Section 5)

• There would need to be flexibility in the width of the riparian zone created to allow for site specific conditions and constraints

• Riparian improvements to be undertaken after any in-channel restoration work such as bank re-profiling

• The Club-tailed dragonfly Gomphus vulgatissimus needs sparsely vegetated banks to haul out on when it is emerging from its exuvium (cast off skin). This should be considered when implementing riparian management measures, thus the universal planting of trees is not necessarily recommended. In addition, periodic stock access to the river should be permitted to prevent rapid vegetation growth, which would be detrimental to the dragonfly.


Woody debris installation Category: Riparian zone management

Description:

• Woody debris is a natural feature of rivers where adjacent trees or branches fall into the channel. It provides a variety of important ecological and small-scale geomorphological functions;

• Woody debris can include whole trees, branches, twigs and leaf litter;

• Woody debris could be introduced to areas of straightened, widened or deepened channels to create physical habitat variation;

• Fallen trees should be left in place where possible (anchored if in a flood risk zone or near infrastructure)

• Woody debris can be either installed in the bank to remain in place, or introduced less formally to ‘find its own place’.

Potential benefits:

• Creation of in-channel sinuosity and habitat niches, but unlikely to cause significant erosion in a low energy system;

• Provides small-scale variations in flow velocity providing slower areas of flow and small pools that accumulate finer sediments and act as fish refuges and nursery sites, spawning habitat for bullhead;

• Creates areas of cover and shading that can reduce predation of fish, but also provide foraging sites for terrestrial species such as otter;

• Valuable invertebrate and algae habitats, creating food sources for fish, helping to sustain aquatic/terrestrial food chain;

• Helps regulate sediment transfer and water quality by temporary trapping of mobile silts, reducing siltation of shallower gravels/riffles and turbidity.

• Introduced river gravels with woody debris improves bed structure, flow variation and habitat diversity.

Illustration:

Concept of introduced woody debris to create sinuosity/variability of flow in a straight section of channel

Example of trapped woody debris along the Afon Ceiriog

Potential constraints and other considerations

• Woody debris can become snagged on bridges and other structures and in exceptional events create blockages. When planning work involving the installation of woody debris, consideration should be given to the need to anchor the debris to prevent it being washed downstream and collecting on structures;

• Where the river channel is relatively narrow, woody debris may accumulate in significant quantities, for example where it collects on a fallen tree, which may create an obstruction which the natural flow of the river is incapable of moving. This may increase flood risk to the surrounding land or increase the risk of bank erosion. Where such obstructions occur it may be necessary to intervene to reduce the amount of woody debris in the channel.

Woody debris in channel alters flow patterns and creates bed and bank diversity, for example by encouraging sediment to deposit


Category: Significant channel restoration Bank protection removal

Category: Assisted natural recovery

Description:

• Allowing or assisting non-essential bank reinforcements to degrade can allow the river to develop more natural bank profiles and planform morphology, more able to adjust to changes in flow and sediment supply

• May need to be undertaken in conjunction with re-profiling of the bank face to lower slopes to ensure banks are stable and to maximise habitat gains. This would be through the removal of material from the bank to form a more gently sloping bank face. The actual slope of the bank will depend upon its location and would need to be confirmed during detailed design

Potential benefits:

• Allows natural bank materials to be exposed, allowing natural supply of sediments to channel

• Natural banks support a more diverse range of habitats, including undercut banks and naturally vegetated banks (fish cover and juvenile habitat)

Illustrations:

Past

Future (Year 1)

Future (Year 10)


• Removing bank protection may lead to short term increases in bank erosion, although recovery of the bank face and riparian vegetation will reduce the impact of this

• Removal of bank protection structures should also involve re-profiling the river bank (where banks have been steepened)

• Restricting agricultural use of the riparian zone will require a change in land management along the river channel (see riparian zone management)


Category: Significant channel restoration (major weir)

Remove Weir

Category: Assisted natural recovery (minor weir)

Description:

• Weirs create barriers to downstream passage of flow and sediments and to free-migration of fish and other fauna up and down the river channel

• Removal of weirs may involve removing the structure (wing-walls and bed stones) and bank lowering or widening (re-profiling) to help the channel re-establish a more natural form

• Existing scour pools located below a removed weir may silt up from the margins over time, this may become colonised with vegetation creating additional variation in habitat

Potential benefits:

• Allows more natural water level variations upstream (reduces deep water from impoundment)

• Enables natural downstream sediment transport and reduces upstream silt smothering of river bed caused by impoundment

• Allows the development of more varied flow types upstream of the former structure, increasing habitat variety including potential areas suitable for Ranunculus and other macrophytes

• Allows the river channel morphology to respond and adjust to changes in flow and sediment supply, creating diverse channel morphology

• Removes barriers or obstacles to bullhead, and brook lamprey allowing them to move freely between habitats and reduces the genetically isolated populations

• Reduces holding time of salmonids below structures where they are at increased risk of predation/exploitation, loss of body condition and falling back to spawn on sub optimum habitats

• Improves longitudinal connectivity by opening of upper catchments so that optimum habitats not currently utilised can be reached

Illustration:

Before weir removal

After weir removal


• Weir removal can lead to significant lowering of water levels upstream, this may lead to some slumping of banks and adjustment of channel shape over time. Further feasibility work is recommended (see Section 5)

• Weir removal can be undertaken in conjunction with bank re-profiling to maximise morphological improvements

Following recovery - flow variations and depositional features created upon weir removal

‘Present’ - weir impounding flow upstream with scour pool downstream


Embankment breach Category: Assisted natural recovery

Description:

• Breaching of approximately 30m stretches of embankments (i.e. removing parts of embankments that are currently not failing of their own accord) at ingress and egress points on the river channel will assist the retreat of the embankments through fluvial scour.

Potential benefits:

• Provides connectivity between the river channel and the surrounding floodplain reducing flood impacts downstream

• Reduces ‘wash out’ impact of flood flows on in-channel habitats and ecology by allowing water flow energy to dissipate beyond the channel (removing the risk of catastrophic failure of the embankments in high flow events)

• Allows the deposition of fine sediment onto the floodplain thereby reducing the likelihood of the deposition of fine sediment within the river channel

• Improves drainage of the floodplain by allowing surface water to drain freely into the river channel

• Removes the risk of catastrophic failure of the embankment where the river bed has aggraded between the embankments

Illustration:


• Will increase the frequency of floodplain inundation which may necessitate changes in farming practices on the floodplain

Present

Following recovery (year 1)

Following recovery (year 10) varied flora establishes


Retreat of banks into the embankments Category: Natural recovery

Description:

• Allowing the unmanaged natural retreat of embankments into agricultural land improves river morphology and habitats at minimal financial cost

• The washing out of bank protection previously instated to prevent embankment erosion has allowed the retreat of embankments at the Dee meanders

Potential benefits:

• Provides connectivity between the river channel and the surrounding floodplain reducing flood impacts downstream

• Reduces ‘wash out’ impact of flood flows on in-channel habitats (depositional features) and ecology by allowing water flow energy to dissipate beyond the channel

• Allows the deposition of fine sediment onto the floodplain thereby reducing the likelihood of the deposition of fine sediment within the river channel or on relict fluvial morphology features within the existing SSSI

• Improves drainage of the floodplain by allowing surface water to drain freely into the river channel

Illustration:


• Will increase the frequency of floodplain inundation which may necessitate changes in farming practices on the floodplain

Past

After recovery (year 1)

After recovery (year 10)

Embankment constructed in the past to protect farmland. At some locations today rotational slips occur

Fluvial scour has led to rotational slips, bank slumps and the retreat of embankments in places. Fencing will encourage the riparian zone growth

Embankment retreat will reconnect the river with floodplain. Fencing will encourage riparian zone and provide cover for river species


Realign to a more natural course Category: Significant channel restoration

Description:

Involves creating a new section of river channel along a different course to the existing channel, down which river flow will be re-routed. This may include:

• Complete channel realignment – diverting all the river flow down a new channel alignment and infilling the pre-restoration channel

• Creating a secondary channel – diverting some of the river flow down a new section of channel while retaining the pre-restoration channel

• Reconnecting old meander bends – excavating and re-connecting former meanders and infilling the sections of channel which formerly bypassed these bends

• Creating back waters - excavating short sections of channel off the existing or proposed channel alignment to provide an area of still water

• Locally widen the channel – excavating short section of the channel to vary a uniform channel width and promote the deposition of gravel and development of spawning beds

Potential benefits:

• Provides a more natural channel planform

• Increase in channel length and therefore physical habitat availability

• Allows the river to undergo natural morphological change in response to changes in flow and sediment supply

• Creates a more varied channel morphology improving flow and physical habitat diversity for a range of species, including macro invertebrates and fish including:

- Gravels and shallow, fast flow types are important spawning and juvenile habitats for lamprey, salmonids, bullhead and invertebrates

- Pools will provide deeper cover for salmonid life stages and resting areas between higher energy flow types

- Backwaters and associated low energy flow types create refuges for species during high flows and provide depository habitats for lamprey ammocoetes

• Composed of natural bed and bank materials improving the physical diversity, for examples:

- Exposed gravels provide habitat for macro invertebrates

NB although categorised as ‘significant restoration’, the identified areas are typically relatively small in the context of each reach.

Illustration:

Present

Restoration to more sinuous channel



• Requires works within the river channel and may result in a period of disturbance, especially during the connection of new sections of channel

• Significant damage/loss of existing habitats may occur in the short to middle term

• Short-term period of channel adjustment increases the amount and rate of erosion and sediment deposition

• Channel realignment may necessitate the relocation of services which cross the flood plain such as drains, water mains, electricity cables (above or below ground) and gas mains

• Requires excavation which may require consideration of ground contamination and presence of buried archaeology

• Potential impacts on agriculture through changes to frequency of flooding

• Some loss of land and potential ownership issues

• Infrastructure

• Management of land/crossings

• Archaeological interest


4 Reach-scale restoration options

4.1 Organisation of the options

The assessment of the need for channel restoration, described in Section 2, involved dividing the River Dee/ Afon Dyfrdwy SSSIs and SAC into reaches based on geomorphological and ecological conditions recorded in the field survey, aerial photographs and the information recorded in the Hill and Emery (2005) Fluvial Audit. In the majority of cases the extent of the reaches was defined based on the type of restoration degree of intervention required to bring reach up to favourable condition (Table 4-1).

Table 4-1 The degree of intervention required along the SSSI/SAC on a reach specific basis

Location SSSI designation CCW management unit (English SSSI unit in brackets)

Restoration category

Afon Mynach Afon Dyfrdwy (River Dee) SSSI

16 Significant restoration

Afon Meloch Afon Dyfrdwy (River Dee) SSSI


Afon Ceiriog Afon Dyfrdwy (River Dee) SSSI / River Dee (England) SSSI

18 and 19 (3) Significant restoration

Upper Dee – near Llandrillo



Upper Dee – Cynwyd


4 Riparian zone management

Upper Dee – Corwen



Middle Dee – Carrog



Assisted natural recovery

Lower Dee – Dee meanders


10 and11 (4 and 5)

Natural recovery



12 (1) Natural recovery

4.2 Restoration plans

For those reaches where restoration has been identified (Figures 4-1 to 4-4) a selection of sites have been chosen and developed into individual plans which set out the suggested approach for each location.

The plans comprise the following components:

• Site name

• Category of intervention required

• SSSI designation

• CCW management unit and associated SSSI unit number for River Dee (England) SSSI


• November/ December 2012 surveyed reach reference number

• Start and end grid references

• Location map

• Annotated maps, aerial and ground based photographs detailing the suggested actions

• Summary of potential benefits and constraints. The dimensions of restoration actions shown on the plans are indicative and do not necessarily represent the actual footprint of the activity, which would be determined by future more detailed planning of actions in discussion with landowners (see Section 5).

The plan outlines the options that have been identified as desirable to meet the conservation objectives for the river. This version of the restoration plan has been updated to include general feedback received during the one month online consultation held between the 15th February 2013 and 15th March 2013 and a consultation event held on the 28th February 2013 at the Wild Pheasant Hotel, Llangollen. More detailed comments on specific river reaches will be held on file and used to inform future discussions with stakeholders as reach specific restoration projects are taken forward.


Figure 4.1 Map showing locations of potential riparian zone management in the upper half of the SSSI/SAC


Figure 4.2 Map showing locations of potential riparian zone management in the lower half of the SSSI/SAC


Figure 4.3 Map showing locations of potential channel restoration in the upper half of the SSSI/SAC


Figure 4.4 Map showing locations of potential channel restoration in the lower half of the SSSI/SAC

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Category: Significant restoration Afon Mynach – between Glan-yr-afon and Frongoch Designation: Afon Dyfrdwy SSSI CCW management unit: 16

Technical report reach: MYN004

Start NGR: SH 90607 39659 End NGR: SH 90584 39122

Location:

Context:

• The channel is relatively straight in this section with a uniform width. The upper and middle reaches of the river exhibit an irregular meandering and sinuous planform, with a varied width

• The channel has a bedrock, boulder and cobble bed which creates a varied flow including step-pool sequence

Key issues:

• Approximately 560m of channel has been straightened, potentially to improve land drainage and maximise productivity of land

• Bank protection in association with the straightened section

• Riparian zone degradation

Restoration actions:

Action Site specific details (refer also to

Section 3) Site specific benefits (refer also to Section 3)

Site specific constraints

Channel realignment Realign channel to recreate a winding course and recreate a sediment sink. Increase width of channel, creating back water areas

Improve flow and substrate diversity Farm on left bank at SH 90621 39458

Remove bank protection

Remove the bank protection associated with the realignment to create a natural bank profile

Improves bank habitat Infrastructure, such as the road bridge at Frongoch

Improve the riparian corridor

Tree planting to restore riparian zone Fence off fields with livestock to address poaching and encourage growth of riparian zone

Reduced fine sediment input from surface runoff and increased marginal cover for fish

Will require some change in land management

Upstream view illustrating straight planform and uniform width and flow. Opportunity to create a more natural course. One option could be to increase the width of the channel at certain locations to create backwater areas. These will allow deposition of gravel and cobbles and will potentially create spawning areas and refuge areas for aquatic species.

Example of the typical morphology and ecological habitats found upstream.

Evidence of unmown/ uncultivated riparian corridor, which allows development of a variety of flora.

Continuous line of deciduous trees along right bank provides cover for fauna such as otter. Potential source of woody debris and in-channel habitats.

Downstream view, left bank. Absence of trees on left bank – opportunity to create buffer zone for an erodible corridor to promote natural recovery within the buffer strip. This would improve in-channel and bank geomorphological diversity and in-channel riparian zone habitat.

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Category: Significant restoration Afon Meloch – near Cefn-ddwysarn Designation: Afon Dyfrdwy SSSI CCW management unit: 17

Technical report reach: MEL004

Start NGR: SH 96260 38867 End NGR: SH 96434 38807

Location:

Context:

• The channel is confined by topography in a v-shaped valley. Bedrock and boulder bed creating varied flow, including step-pool sequence. Exposed tree roots are present

Key issues:

• Channel realignment has resulted in uniform channel width and uniform bank profiles and consequent low geomorphological diversity

• Embankment on the left of realigned reach has isolated the floodplain from the channel

• Land use (i.e grazing pressure) has resulted in riparian zone degradation, which results in fine sediment input and banks becoming prone to erosion

• Approximately 230m of channel has been realigned and embanked to follow field boundaries. Banks have been reinforced along some sections to protect infrastructure

Restoration activities:




Channel realignment Realign channel to recreate a more natural sinuous course and recreate associated habitats

Improves flow and substrate diversity. Will perhaps create habitats suitable for fish spawning

Agricultural land may be lost to the river channel

Remove embankment Remove embankment that runs in parallel with the realigned section on left bank

Increase connectivity of channel with floodplain

Would increase the likelihood and frequency of flooding of the field, but reduce any ponding behind the current embankment

Improve riparian zone Manage grazing pressure. Tree planting to improve riparian zone Fence off fields with livestock to encourage growth of riparian zone. This could be a temporary stock exclusion measure


Will require some change in land management on both banks

Tree planting would provide cover for fish and otters and improve riparian zone habitat.

Recreating meanders would encourage deposition of gravels, increasing spawning habitat for salmonids. Improving flow variation will create more varied habitat for fish species.

Opportunity to remove bank protection, to expose natural bank material and allow bank face vegetation to develop.

Direction of flow

Direction of flow

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Category: Significant restoration Afon Ceiriog – Llanarmon Dyffryn Ceiriog Designation: Afon Dyfrdwy SSSI CCW management unit: 18

Technical report reach: CEI002SP

Start NGR: SJ 15503 33147 End NGR: SJ 15898 32858

Location:

Context:

• The Afon Ceiriog generally has a winding channel, which is confined by glacial valley sides

• Bed material is predominantly cobbles and boulders, with bedrock in places

• Exposed tree roots present along most of the channel Key issues:

• Realigned, straightened section of river and associated incising as the river is unable to erode laterally. This can result in deeper bank and bed than would be expected naturally

• Localised areas of bank protection through settlements

• Riparian zone degradation due to land use pressures




Channel realignment Realign straightened section to mimic downstream natural meanders but also to re-create a sediment sink

Improved deposition of gravels (connectivity between salmonid spawning and parr habitats). Increased diversity in flow and substrate types

Loss of field area


Remove bank protection Improves bank habitat along both banks Loss of field area due to increase erosion into banks. May allow inundation of fields during high flows

Improve riparian zone Manage grazing pressure. Tree planting to improve riparian zone Fence off fields with livestock to encourage growth of riparian zone. This could be a temporary stock exclusion measure

Reduced fine sediment input from surface runoff and increased marginal cover for fish. Reduced runoff from fields

Will require some change in land management along both banks

Tree planting would reduce runoff from arable land and increase cover for fish and otters. The trees would also provide a source of woody debris, encouraging scour and provide in-channel cover for fish.

Realign this section within an erodible corridor buffer zone to create a more sinuous course which would encourage natural geomorphology processes such as gravel deposition. Gravel deposition may be utilised as spawning habitat. Increases in flow and substrate diversity will improve the extent of aquatic habitats available.

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Category: Significant restoration Upper Dee – near Llandrillo Designation: Afon Dyfrdwy SSSI CCW management unit: 4

Technical report reach: DEE001


Location:

Context:

• The river has a sinuous planform with a thin, semi-continuous tree-line along both river banks. Land use is predominantly grazing

• This section of the Upper Dee, surveyed in full by the Hill and Emery (2005) Fluvial Audit has extensive fragmented bank protection on both bank sides. Much of this appears to have been placed to prevent the lateral migration of the river into adjacent farmland

Key issues:

• Localised bank protection of predominantly laid stone and/or boulders which are altering the natural geomorphological processes

• Embankment causing loss of floodplain connectivity with the channel caused by land use pressures, namely grazing with livestock access to the river


• Poaching of banks caused by livestock access to the river




Breach embankment Remove 30m sections of embankment Increase channel connectivity to floodplain Would increase the likelihood and frequency of flooding of the field

Bank protection removal

Remove historic bank protection Improves bank habitat Improves geomorphology processes such as scour and lateral migration of the river channel

Tree roots have grown in and around sections of stone bank protection and therefore it may be very difficult to remove bank protection in places

Improve riparian corridor

Manage grazing pressure. Tree planting to improve riparian zone Fence off fields containing livestock to encourage growth of riparian zone. This could be a temporary stock exclusion measure


Will require some change in land management on both banks. Open views of the river may hold important cultural heritage landscape value

Remove historic bank protection improve bank side vegetation and geomorphological processes, such as scour and lateral migration of the river channel. Improve riparian corridor by fencing off land used for livestock grazing and planting trees.

Remove embankment to allow flood flows to dissipate into the floodplain where they would naturally be expected to do so.

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Category: Riparian zone management Upper Dee - Cynwyd Designation: Afon Dyfrdwy SSSI CCW management unit: 4

Technical report reach: DEE001SP


Location:

Context:

• Near Cynwyd the adjacent land use to the River Dee is predominantly pasture, grazed by cows and sheep. The fields grazed by sheep were observed to have less severe poaching than sections grazed by cattle (observed by the ford)

• The river had a continuous line of tree and almost continuous fencing on the right bank. Tree cover was scattered on the left bank and the riparian vegetation was generally semi-improved grassland. There were a couple of pockets of fenced wooded areas that create habitat for a variety of flora and fauna

• The river has an irregular meandering pattern. The banks are largely natural with some discrete pockets of bank protection

• The dominant function of the river is a sediment transfer, with limited pockets of fluvial erosion

Key issues:

• Simple riparian zone structure on left bank (semi-improved and scattered trees).

• Small areas of bare ground exposed by poaching where fields are grazed and fencing is absent

• Severe poaching (large area without vegetation cover) supplying an elevated rate of fine sediment

Action Site specific details (refer also to Section 3) Site specific benefits (refer also

to Section 3) Site specific constraints

Tree planting to increase shading and variety of habitats

Manage grazing pressure/ create a fenced corridor between farm and river to reduce extent of poaching at ford

Improve riparian corridor along left bank

Manage grazing pressure along left bank to encourage the growth of the riparian zone

Reduced fine sediment input from surface runoff and increased marginal cover for fish. Improve riparian vegetation structure, habitat and bank stability

Will require some change in land management, specifically along the left bank. Will need controlled water access points for livestock

Direction of flow

Elevated rate of sediment supply caused by poaching at ford. There is an opportunity to reduce sediment input by creating a fenced corridor between farm, ford and field on right bank.

Ford

Small pocket of poaching, approximately 5m long by 1.5m wide. Semi-improved grassland on left bank, some tree in distance. Opportunity for riparian improvement.

Pasture land on left and right bank, no poaching. Scattered occurrence of trees on left bank. Continuous tree cover on right bank. Opportunity to improve habitats on left bank.

Varied habitat with tree cover. Area fenced off from livestock.

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Category: Riparian zone management Upper Dee - Corwen Designation: Afon Dyfrdwy SSSI CCW management unit: 4



Location:

Context:

• Near Corwen, the adjacent land use along this reach is predominantly pasture grazed by sheep. The river is wide and sinuous with gentle and undercut banks. The riparian vegetation has discontinuous tree-line, with fencing present along some sections excluding livestock from the river

• A major bridge with in-channel piers crosses the river Key issues:

• A large area of poaching causing fine sediment input into the river at vehicle crossing points (tractors) on both river banks. The bed of the river may become compacted

• Poaching of banks by livestock where fencing is absent which introduces fine sediment into the channel


• Bank protection and in-channel piers associated with Corwen Bridge







Would require a change in land management along both banks

Ranunculus

Ephemeral field ditch, grass lined and trampled; a source of sediment.

Downstream of Corwen Bridge. Continuous line of single trees.

Isolated/ scattered tree line. Area of erosion, which introduces fine sediment into the channel and bank instability.

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Category: Riparian zone management Middle Dee - Carrog Designation: Afon Dyfrdwy SSSI CCW management unit: 4



Location:

Context:

• Slightly sinuous channel running through pasture. There is semi-continuous tree cover along both banks along this reach. Erosion of banks due to poor riparian vegetation structure occurs where trees are absent

• The river in this reach is constrained in parts due to the parallel running railway line. Uniform channel width predominant with some depositional features; point bars on meander bends

Key issues:

• Simple plant composition in riparian zone on both banks

• Minor poaching (fields grazed by sheep during 2012 survey)







Would require some change in land management

Simple riparian vegetation – grass covered bank top with a single line of trees. Exposed tree roots potentially provides habitat for otter and fish during high flows.

Absence of tree cover and variety of flora. Grass covered bank tops and face with evidence of poaching.

Confined by railway

Remnants of historic bank protection. These isolated patches have minimal impact on the river’s geomorphology and ecology.

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Category: Assisted natural recovery (where embankment breaching is recommended)

Category: Natural recovery (where retreat of banks into embankment is recommended) Lower Dee – Dee meanders

Designation: River Dee SSSI (units 4 & 5) CCW management unit: 10 and 11

Technical report reach: DEE002


Location:

Context:

• This section is widely known for its tortuous meanders and is designated as a SSSI and a GCR for fluvial geomorphology

• Historic embankments, constructed to prevent flooding into adjacent farmland, line the Dee meanders, with some set back on the inside of bends. Records show that bank protection was placed to reinforce the embankments but this largely appears to have washed out. Now the unmanaged retreat of embankments is occurring along some stretches of the meanders

• Historically trees would have been removed from riparian zone as roots systems would destabilise embankments and cause them to be breached. Consequently there is a widespread lack of riparian zone and associated channel cover for aquatic species. Lack of fencing has also led to poaching of bank sides

Key issues:

• Extensive embankments along this reach preventing floodplain connectivity

• Riparian zone degradation due to historic management and past and present land use which impacts on riparian and channel habitat

• Poaching




Breach embankment Partially remove embankments where necessary (i.e. remove 30m sections where unmanaged retreat is not occurring). This will encourage scour and the subsequent natural retreat of banks into embankments

Reconnect channel with floodplain Land owner consent Protected species issues Reconnection of river with floodplain will inevitably lead to more frequent flooding of farmland in places

Unmanaged retreat of embankments

Allow unmanaged retreat of meanders and continued erosion of embankments

Natural processes putting sediments into channel for spawning and juvenile habitats Increase in flow variation with return to naturalised channel

Reconnection of river with floodplain will inevitably lead to more frequent flooding of farmland in places



Reduced fine sediment input from surface runoff and increased marginal cover for fish. Reduced runoff from fields with potential pollutants such as phosphates


Opportunity to allow banks to retreat into embankments. Recommended where adjacent land use is agricultural

Eroding cliff on the outside of a meander bend. Improved riparian vegetation cover will assist in stabilising this accelerated erosion to maintain semi-natural eroding cliff

Example of embankment that is not currently eroding and may benefit from breached embankments (assisted natural recovery) to reconnect river with floodplain

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Category: Natural recovery Lower Dee – between Farndon and Aldford Designation: River Dee SSSI (unit 1) CCW management unit: 12

Technical report reach: DEE003 and DEE004


Location:

Context: This reach is sinuous and extensively embanked to protect adjacent land. Failure of embankments is occurring along this section, as illustrated below. Predominantly arable land use where fine sediment may be introduced into the channel from runoff. This section is also influenced from freshwater back up from tides down at Chester weir. It is also downstream of the Shocklach meandering section Key issues: Informal boat moorings and holiday homes (caravans and stone houses) Embankments on left bank (eroding). Localised areas of embankments on right bank. Note, flooding was recorded in fields on right bank Shrub lined embankments along left bank (no signs of erosion). Note, flooding was observed behind embankments, but likely to have arisen due to tributaries (including Pulford Brook) over topping due to the head of water in the Dee




Allow embankment retreat within an erodible corridor

Allow unmanaged retreat of meanders and continued erosion of embankments

Natural processes putting sediments into channel for spawning and juvenile habitats Increase in flow variation with return to naturalised channel

Reconnection of river with floodplain will inevitably lead to more frequent flooding of farmland in places

Breach embankment Remove 30m sections of embankment Increase connectivity of channel with floodplain

Land owner consent. Protected species issues Reconnection of river with floodplain will inevitably lead to more frequent flooding of farmland in places



Reduced fine sediment input from surface runoff and increased marginal cover for fish. Reduced runoff from fields with potential pollutants such as phosphates


Fluvial erosion and geotechnical failure of embankments causing bank instability and introduction of fine sediment into channel.

Stable, shrub lined embankments.

Flooding of adjacent arable fields.

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Afon Ceiriog - Above fishery near Pont Faen Designation: Afon Dyfrdwy (River Dee) SSSI

CCW management unit: 18

Restoration benefits: This is the third obstruction to fish passage on the Ceiriog in an upstream direction from the confluence with the Dee. Removing/ modifying may improve passage for lamprey (providing they can pass Erbistock Weir on the main stem) and increase connectivity between bullhead and brook lamprey populations. Restoration constraints: This weir is used to divert water into the fishery, therefore it may be infeasible to completely remove it. Modification may produce temporary silt that will flow downstream and also perhaps into the fishery. Ecological effects: Potential obstruction to salmonid migration particularly in low flow conditions but passable under higher flow conditions. Delays in migration may increase concentration of fish below the structure, increase predation or exploitation, increase the chance of disease among fish leading to reduced fish condition and result in fish using sub-optimal habitats or failing to spawn at all.

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Afon Ceiriog Designation: River Dee (England) SSSI


Brynkinalt gauging weir Restoration benefits: This is the second obstruction to fish passage on the River Ceiriog in an upstream direction from the confluence with the Dee. Removing /modifying may improve passage for lamprey (providing they can pass Erbistock Weir on the main stem) and increase connectivity between bullhead and brook lamprey populations. Restoration constraints: This is a gauging weir is therefore needed to calculate flows. Ecological effects: Potential obstruction to salmonid migration particularly in low flow conditions but passable under higher flow conditions. Unlikely to allow lamprey and bullhead to ascend, especially in low flow conditions.

Unnamed weir Restoration benefits: This is the first obstruction to fish passage on the River Ceiriog in an upstream direction from the confluence with the Dee. Some migratory species can pass this, but removing/modifying may improve passage for species such as lamprey.

Restoration constraints: Nearby farm. It is unknown what this weir was used for. It does not appear to be used today. Ecological effects: Potential obstruction to salmonid migration particularly in low flow conditions but passable under higher flow conditions. Unlikely to allow lamprey and bullhead to ascend, especially in low flow conditions.

Unnamed weir

Brynkinalt gauging weir

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Upper Dee Designation: Afon Dyfrdwy (River Dee) SSSI

CCW management units: 2, 3 and 15

Unnamed weir Not visited during surveys Restoration benefits: Enable more salmonids, lamprey and bullhead to ascend upstream. Restoration constraints: Urban Development. Part of Bala Lake System, constructed to facilitate the delivery of public water supply.

Weir by Bala Enterprise Park Restoration benefits: Some migratory species can currently pass this, but removing/modifying may improve ascension success rate/ reducing downstream holding times for migrating fish. Restoration constraints: Urban Development.

Part of Bala Lake System, constructed to facilitate the delivery of public water supply.

Salmon Steps - Bala Lake System Restoration benefits: Some migratory species can pass this, but removing/modifying may improve ascension success rate / reducing downstream holding times for migrating fish. Restoration constraints: Urban development. Part of Bala Lake System, constructed to facilitate the delivery of public water supply.

Bala gauging weir Not visited during surveys. Restoration benefits: This is the eight obstruction to fish passage on mainstem Dee in an upstream direction from Chester weir. Removal/modification would allow more migrating fish to access the river above. Restoration constraints: This is a gauging weir needed to calculate flows.

Salmon Steps

Weir by Bala Enterprise Park

Bala gauging weir

Unnamed weir

Ecological effects: Unlikely to significantly obstruct salmonid passage under most flow conditions due to water depth and weir height being suitable for all fish species to navigate

Ecological effect: Fish pass will ensure fish passage under most flow conditions. Unlikely to be suitable for lamprey or bullhead passage due to the velocity of water over the fish pas leading to use of sub optimal spawning habitats and potentially a reduction or failure to spawn

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Upper Dee – Unnamed weir Designation: Afon Dyfrdwy (River Dee) SSSI


Restoration benefits: This is the seventh obstruction to fish passage on main stem Dee in an upstream direction from Chester weir. Removal/modification would allow more migrating fish to access the river above. Restoration constraints: Weir needed to feed water into fish pond at Bodweni. Ecological effect: Potential obstruction to salmonid migration particularly in low flow conditions. Delays in migration may increase concentration of fish below the structure, increase predation or exploitation, increase the chance of disease among fish leading to reduced fish condition and result in fish using sub-optimal habitats or failing to spawn at all.

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Middle Dee – Horseshoe Falls Designation: Afon Dyfrdwy (River Dee) SSSI

CCW management unit: 5/6

Restoration benefits: This is the sixth major barrier to fish passage on the mainstem Dee in an upstream direction from Chester weir. Removal/improvement would open up the river to most migrating fish up until the next barrier to fish passage. Modifying the weir would facilitate passage for lamprey (if present in teh catchment above Eribstock), allowing access to suitable spawning habitat upstream. Restoration constraints: Horseshoe Falls is needed to maintain water in the Llangollen Canal. Cultural heritage of Horseshoe Falls. Ecological effects: Potential obstruction to salmonid and lamprey migration due to the vertical steepness of the weir. However it may be passable under higher flow conditions. Delays in migration and increased holding time beneath the structure may lead to increased concentration of fish, increase exploitation rates and lowering of water quality. This can cause a reduction of fish condition through disease and result in fish using sub-optimal habitats or failing to spawn at all if outside of the main run. Unlikely to allow lamprey and bullhead to ascend due to the vertical steepness of the weir.

Ponding upstream as a result of Horseshoe Falls. Modification of the weir may help reduce this ponding and increase flow variability upstream

Fencing and tree planting recommended to address degraded riparian zone and poaching

Horseshoe Falls

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Middle Dee – Llangollen Weirs Designation: Afon Dyfrdwy (River Dee) SSSI


Upstream weir Restoration benefits: This is the fifth obstruction to migrating fish on the main stem Dee in an upstream direction from Chester weir. Once used to divert water into adjacent corn mill. Removing/improving this will help open up the catchment above this weir to more migratory fish. Restoration constraints: Urban development. Ecological effects: Potential obstruction to salmonid migration due to flow rate but passable under higher flow conditions. Delays in migration and increased holding time beneath the structure may lead to increased concentration of fish and lowering of water quality. This can cause a reduction of fish condition through disease and result in fish using sub-optimal habitats or failing to spawn at all if outside of the main run. Unlikely to allow lamprey and bullhead to ascend due to the steepness and fast flow of water over the weir at most times.

Downstream weir Restoration benefits: This is the fourth major obstruction to migratory fish passage on the main stem Dee in an upstream direction from Chester weir. Removing/ improving this will help open up the catchment above this weir to ascending salmon. Modification will improve passability, reducing holding times under lower flows and reducing exploitation. Restoration constraints: Weir size, urban development, cultural heritage. Ecological effects: Potential obstruction to salmonid migration, but passable under most flow conditions. However, delays in ascending multiple weirs through Llangollen reduce the time available after ascending the structures to find suitable spawning habitat leading to selection of suboptimal spawning habitat. Unlikely to allow lamprey and bullhead to ascend due to fast flow of water over the weir at most times.

Upstream weir

Variable flow and vegetated mid channel island at Llangollen.

Downstream weir

Constraints with weir removal/ modification due to urban development and flood walls on each bank

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Middle Dee Designation: Afon Dyfrdwy (River Dee) SSSI

CCW management unit: 8/9

Manley Hall gauging weir Restoration benefits: This is the third major barrier to migratory fish passage on the mainstem Dee in an upstream direction from Chester weir. Restoration constraints: Gauging weir needed for calculating flows. Ecological effects: Potential obstruction to salmonid migration but passable under higher flow conditions. Delays in migration may increase concentration of fish below the structure, increase predation or exploitation, increase the chance of disease among fish leading to reduced fish condition and result in fish using sub-optimal habitats or failing to spawn at all. Unlikely to allow lamprey and bullhead to ascend.

Erbistock Weir Restoration benefits: This is the second major obstruction to migratory fish passage on the mainstem Dee in an upstream direction from Chester weir. Still used to power machinery inside the mill. Improvement to passability for lamprey will increase spawning success of sea lamprey through the catchment. Restoration constraints: Weir size, risk to old mill on left bank which may be of historic value. Sediment release. Cultural heritage of mill and weir.

Ecological effects: Potential obstruction to salmonid migration due to weir height, but passable under higher flow conditions. Delays in migration may reduce fish condition, increase concentration of fish below the structure and increase exploitation rates. Significant obstruction to lamprey migration due to flow velocity and weir height.

Erbistock weir (CCW unit 8/9)

Manley Hall gauging weir (CCW unit 8)

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Lower Dee – Chester Weir Designation: River Dee (England) SSSI (unit 1)


Restoration benefits: Historic weir originally built to serve medieval mills and then restored for hydroelectric power in the early 20

th century. Now

used for abstractions and to prevent tidal ingress for all but highest tides.This is the first obstruction to migratory species on the River Dee from the esturary. May impede species ascending the watercourse, although fisheries data suggests both salmon and lamprey can pass above this structure. Removal or modification of this weir will increase the rate of ascension for fish and lamprey into the catchment. Restoration constraints: Urban development. Cultural heritage of weir; weir is a listed structure. Ecological effects: Fish pass will ensure fish passage under most flow conditions.


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5 Implementing the plan

5.1 Working with landowners and land managers

To restore the River Dee/ Afon Dyfrdwy SSSIs and SAC to favourable condition, the Environment Agency, Environment Agency Wales, Natural England and the Countryside Council for Wales all recognise the need for effective and positive engagement with land owners and land managers in the Dee catchment. Delivering the restoration plan will involve working in partnership with a range of individuals and organisations including: angling groups, Welsh Dee Trust, United Utilities, landowners near the river, National Farmers Union (NFU), the Clwydian Range and Dee Valley Area of Outstanding Natural Beauty (AONB) Joint Advisory Committee (JAC), Dŵr Cymru Welsh Water and the Canal & River Trust. The themes of key comments from the consultation event are summarised in Table 5-1

Table 5-1 Themes of key comments from the consultation event

Flow regulation – Effects on river ecology and migratory fish

Perceived as the main pressure on the River Dee/ Afon Dyfrdwy and there was general concern over why this was not been considered in more depth in the restoration reports. Sites not visited as part of this study that are affected by flow regulation include the Tryweryn and the Estuary below Chester Weir.

Fish counts

Angling clubs stated that tributaries outside the SSSIs are important spawning habitats and should be investigated to identify why salmon numbers are in decline (they report that there has been a downward trend in salmon counts on the Tryweryn, particularly since 2006). Sites suggested for investigation include Bala Lake and its tributaries, as well as the River Alwen. They were not convinced that restoration measures would lead to an increase salmon numbers.

Flood risk

Concerns were raised that restoration measures should not lead to a greater risk of urban flooding and loss of productive farmland as a lot of investment has gone into flood defence assets and land drainage over the years.

Riparian zone management –

Fishermen were concerned that extensive tree planting could reduce access to the river. In addition it was perceived that grazing limits the spread of invasive species and also that stabilising banks with trees would reduce the gravel sources for spawning habitats. Some believed there are already enough trees along the river banks.

Invasive species management

Some stakeholders asked for more information on the current management of invasive species and how controlled grazing would remedy the spread of invasive species.

Stakeholder engagement/participation

It was felt that stakeholder engagement for this project could be improved in the future. Many groups/individuals were informed after the study had been undertaken. It was suggested that there are


63

many local people with extensive knowledge that could be of use to this project. This knowledge could be used to take forward future work.

Change to sediment regime

In particular, United Utilities were concerned that measures should not cause an increase in suspended solids or cause sedimentation close to their assets (including intakes) potentially leading to blockages.

Weir/bank protection removal/modification

Numerous viewpoints on weir removal/ modification were aired including that any modifications to weirs must protect their existing function (e.g. Horseshoe Falls maintains water in the Llangollen Canal); weir removal may release gravels and improve spawning habitats; weir removal may lead to bank collapses and affect historical buildings; some weirs have historic/heritage value and money spent on modifying/ removing weirs could be put to better use elsewhere.

Role of agriculture

The National Farmers’ Union (NFU) felt that it important to remind people that it is inevitable that farming will impact the landscape. NFU highlighted concerns that the delivery of environmental benefits could clash with the need for food production, especially with pressures such as climate change and population growth.

Impact on World Heritage Sites

It was emphasised by some consultees that implications of restoration measures on World Heritage Sites should be considered when assessing the feasibility of any of the restoration measures.

Public access and visual enhancement

Future feasibility studies for the implementation of restoration measures should look to enhance both public access and visual amenity.

Finance of restoration measures

There was concern over the current poor uptake of Glastir, particularly as a result of incentives not outweighing costs of implemention. In addition it was pointed out that although basic costings are provided in the Technical Report, this does not show how measures will contribute to meeting European obligations.

Specific comments and responses to comments can be found in Appendix A. For any of the proposals in the plan to be implemented, it will be necessary to work closely with land owners and other stakeholders. Land owners and managers will play an important role in developing the proposals, and in some cases may take ownership of the implementation of the actions with appropriate technical and financial assistance. Whilst some options could be implemented over the next few years, other measures will take longer to organise with the land owners and interested parties. Some reaches will have little active intervention, but may still need agreements on adjacent land use or to allow the river to naturally recover in its own time, which may take many years.


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5.2 Prioritisation and cost

The restoration measures have been prioritised according to the degree of potential improvement to the SSSI/ SAC they will bring. This is a function of the type of restoration measure and the location in the catchment where this measure is suggested. It is very difficult at this stage to quantify the outcomes of a given measure (e.g. how many more salmon could be expected to occur as a result of managing riparian corridors or improving in-river habitat). The premise made here is that 'naturalising' in-channel and riparian habitat should have benefits for most fauna and flora, which should at least maintain or enhance the biodiversity of the river system. In general it is also considered that certain actions prioritised in the headwaters/ tributaries will have benefits potentially extending far downstream. So, for example, riparian zone management to reduce the fine sediment input in the headwaters/ tributaries could have significant local effects as well as reducing some of the sediment loading further downstream in the main stem of the Dee. The actions listed below are ordered in terms of highest priority to lower priority: 1. Improvement of riparian zone throughout the catchment 2. Restoration of tributaries 3. Removal of major weirs 4. Bank protection removal 5. Embankment breach Riparian zone management should be prioritised first as a ubiquitous measure. Following this, it is suggested that the non-regulated tributaries Meloch, Mynach and Ceiriog could be targeted earlier than the main stem Dee. In addition to riparian zone management (already underway in some places) restoration of the tributaries should include re-meandering to potentially improve in-channel habitat, the removal of localised bank protection and the removal of minor weirs. However the removal of these structures is only likely to produce localised ecological improvement to a small number of reaches given the presence of large obstructions to migration in the main stem Dee. The removal of major weirs on the main stem Dee will improve bedload transport from upstream to downstream (this is irrespective of existing passes benefiting fish passage). Removal of larger weirs would, however, improve longitudinal connectivity for several species (including lamprey) and change the morphological character of much longer lengths of the main stem Dee with the elimination of impounded flow and the potential for gravel bars to develop in downstream reaches from material passed more freely along the river bed. For bank protection and embankments there are several options available: allow deterioration of the feature through processes of erosion (and discontinue maintenance); or physically intervene and remove the materials. In the case of embankments, allowing re-connectivity with the floodplain will potentially reduce silt loadings in the Lower Dee, albeit only locally if other areas of floodplain remain protected. It is suggested that those embankments qualifying for intervention should be breached at strategic points to allow sufficient ingress and egress of flood flows. Intervention may be necessary where the river bank is not eroding sufficiently fast into the embankment causing a ‘natural’ breach. Breaching at selected locations allows inundation of the floodplain without the need to breach/ remove the entire embankment, the spoil from which might be costly to dispose of. It is considered that the highest likelihood of unmanaged retreat is in the Dee Meanders reach, where failure of embankments and destruction of bank protection has already occurred to some degree. A third option would be to set-back embankments,


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thereby creating room for the river to erode and meander naturally and also to help reduce the potential for scour within the channel due to confinement of flows by embankments immediately adjacent to the river. This is also known as the ‘erodible river corridor concept’ (Piegay et al., 2005), within which river managers/ riparian owners agree not to implement or maintain erosion protection. This could potentially be a more costly option. Further prioritisation exercises could take place once the EA and Nature conservation bodies undertake further assessment of current knowledge of abundance and distribution of feature species of the SSSIs and SAC, and determine where they feel the greatest benefit could occur if some or all of the suggested measures were instigated. This would provide a basis upon which to estimate cost/benefits in respect of those features of the site. Further investigation is also required before any of the larger scale proposals could be progressed. Potential constraints and benefits would need to be investigated, such as potential impacts on water quality, morphology, biodiversity, fisheries. flood risk, landscape, recreation and cultural heritage. At such a time the EAW, CCW, NE, EA would share that information with stakeholder groups to discuss the options selected and whether other benefits relevant to stakeholder groups could be met. The costs of restoration options for the Dee have been estimated based on similar measures on other projects and on past experience (Table 5-1). The likely annual Higher Level Stewardship (HLS) costs (for England) have also been calculated per hectare but are based on current rates1 and the 12m buffer width for riparian improvement (but this could be more or less). HLS aims to delivery significant environmental benefits in priority areas. However Common Agricultural Policy reform means schemes are under review and will change from 2014 onwards. New scheme details are not currently available. Equivalent Glastir rates for Wales are also given. Glastir commenced Jan 2013, so unlike the agri-environment schemes in England, is still up and running.

Costs will be site specific and will vary according to a number of factors including, for example, the need for further investigations, external contractors, access, reuse or disposal of materials and local import of materials. There are also a number of assumptions attached to the costs (provided in Table 5-2).

1 Common Agricultural Policy (CAP) reform means that Environmental Stewardship schemes

in England are under review and likely to change from 2014. The details of any new scheme are not yet known.


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Table 5-2 Assumptions made when calculating costs. NB. HLS costs based on 2012 rates and subject to change and acceptance into scheme (Glastir costs in parenthesis in last paragraph)

Action Min

Cost

Max

Cost

Assumptions HLS cost (and

Glastir cost)

Remove bank

reinforcement

£75/m £138/m Cost based on length of

reinforced bank

N/A

Remove

embankment

£2/m £138/m Cost based on length of

reinforced bank.

Disposal costs of

material not included

N/A

Remove minor

weir

£5,000 £19,000 Minor weir, landowner or

local contractor to

undertake work. No

detailed assessment

likely to be necessary

N/A

Remove major

weir (and

associated walls)

£60,000 £120,000 Feasibility and detailed

design necessary and

included in costs.

Disposal costs of

demolition materials not

included

N/A

Replace

artificially

straightened

channel with a

more sinuous

channel to create

fish spawning

habitat

£250/m £550/m Based on experience of

projects circa one

kilometre in length.

Assumed rural area and

no major services

diversions required

N/A

Fill gaps in

riparian

vegetation by

planting

£7/m £7/m Assume 50% of channel

length (between both

banks).

Based on 12m

riparian width and

£400/hectare

(£345/hectare)

Improve riparian

corridor

(including tree

planting)

£7/m £7/m Assume 100% of

channel length (divided

between both banks).

Based on 12m

riparian width

£400/hectare

(£379.80/hectare)

Fencing (both

banks)

£2.50/m £13/m Assume 50% of reach

(divided between left

and right bank)

N/A

(Glastir allows for

streamside

fencing either in

Entry level or

under Advanced

e.g. post and rail

at £10.40 per

metre)

Field gate (£149

each)

£298 £894 Assumes 2 as minimum

and 6 as maximum

N/A


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The cost to implement the restoration measures for each of the restoration plans in Section 4 has been calculated by multiplying the costs in Table 5-2 by the length of treatment required. For intervention at embankment sites it is assumed that 30m breaches (i.e. removal of part of the embankment) will be a sufficient length. The minimum and maximum cost for each restoration measure and the total cost for implementing all of the restoration options at each location are presented in Table 5-3.

Table 5-3 Cost of implementing each restoration action for each of the restoration plans in Section 4 (capital costs)

Total cost Location

Restoration measure

Minimum cost

Maximum cost Minimum Maximum

Channel realignment

£142,000 £313,500

Afon Mynach Riparian Zone Management

£36,201 £66,611

£178,201 £380,111

Channel realignment

£60,000 £130,000


£7800 £14,465


£58,000 £58,000

Afon Meloch

Embankment breaching

£60 £4,140

£375,860 £756,605

Channel realignment

£250,000 £550,000

Afon Ceiriog Riparian Zone Management

£66,175 £66,175

£316,175 £616,175


£283,461 £521,568


£56,000 £56,000 Upper Dee – near Llandrillo

Embankment breaching

£60 £414

£339,521 £577,982


£30,227 £55,618 Upper Dee – Cynwyd Riparian Zone

Management £21,983 £21,983

£52,210 £77,601


£16, 257 £29, 912 Upper Dee – Corwen Riparian Zone

Management £8,310 £8, 310

£24,567 £38,222

Middle Dee – Carrog


£6,979 £6,979 £6,979 £6,979

Breach embankments

£480 £33,120

Bank protection removal

£51,960 £95,607 Lower Dee – Dee meanders

Riparian zone management

£214,220

£214,220

£266,660 £342,947


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Total cost Location

Restoration measure

Minimum cost

Maximum cost Minimum Maximum

Breach embankments

£180 £11,240 Lower Dee – between Farndon and Aldford


£27,469 £27,469

£27,649 £38,709

Table 5-4 shows the HLS and Glastir costs for the implementation of the restoration measures for each of the restoration plans in Section 4 (only applicable to riparian zone management).

Table 5-4 Maximum Glastir and HLS costs (based on assumption that 100% of length of bank will be planted with shrubs and trees)

Location Restoration Measure

Approximate area (ha)

HLS/Glastir cost

Afon Mynach Riparian zone management

2.14 £812

Afon Meloch Riparian zone management

3.93 £1494

Afon Ceiriog Riparian zone management

17.76 £6744

Upper Dee – near Llandrillo


10.97 £4168

Upper Dee – Cynwyd


3.42 £1299

Upper Dee – Corwen


2.63 £999

Middle Dee –Carrog


1.26 £480

Lower Dee – Dee meanders


93.3 £37,319



3 £1199

Table 5-5 shows the total capital costs of restoration for each measure/ action for the whole Dee catchment, together with an overall total to restore the River Dee/ Afon Dyfrdwy SSSIs and SAC (excluding weir removal).

Table 5-5 Combined overall cost for restoration of River Dee (England) SSSI and Afon Dyfrdwy (River Dee) SSSI

Measure/ Action Min Cost Max Cost HLS/Glastir Cost Channel realignment £758, 660 £1,669, 054 Riparian Zone Management

£971,300 £971,300 HLS - £39,195 Glastir - £44,360

Bank Protection £395,882 £728,424 Embankments (breaches)

£780 £48,914

TOTAL £2,126,662 £3,417,692 £83,555


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The Environment Agency, Environment Agency Wales, Natural England and CCW will seek to work in partnership with a range of external parties, including angling clubs and river and wildlife trusts, to deliver the actions.

5.3 Shaping the actions

The level of detail to which the restoration options are described in this report reflects a strategic focus. To accurately cost and implement the restoration actions, further work will be required to undertake feasibility studies and then develop outline and detailed designs for each of the restoration actions included in the plans. The degree of feasibility assessment and design work required will depend upon the details of each restoration action and the outcomes of further consultation. An indication of the potential scale of this work is provided in Table 5-6. Both stages of this further work would need to be undertaken in co-operation with land owners who will play an important role in shaping the detail of future restoration work. Co-operation and engagement will not end with the implementation of restoration measures. The Environment Agency, Environment Agency Wales, Natural England and CCW will continue to work proactively with land owners in England and Wales to ensure the long terms success and sustainability of the restoration measures. This will include monitoring the restored areas and where necessary, undertaking adaptive management. Management of the river and its surroundings is an ongoing and long term process, with an emphasis on maximising the habitat value of the river environment. Examples of the types of management that might be necessary include:

• Managing woody debris within the channel in line with best practice

• Managing living trees through coppicing or pollarding to maintain healthy trees and managing the supply of woody debris or the degree of shading

• Keeping fences in a good state of repair to exclude farm animals from poaching river banks

• Rarely but occasionally removing blockages, caused by a localised build-up of debris (including wood or rubbish), from the river channel.

5.4 An opportunity

Floodplain land owners and managers are currently faced with a range of challenges including:

• Crop damage and/or soil loss associated due to flood events (which are natural, but due to climatic change likely to increase in frequency and magnitude in the future)

• Managing nutrient runoff in accordance with the catchment diffuse water pollution plan

• Maintaining land drainage in areas where the river is re-adjusting following the cessation of land drainage work

• Limits on water availability for abstraction, especially during the summer (which is likely to increase in frequency and severity due to climatic change)..

The Statutory Bodies recognise these pressures and want to work with farmers to help them deal with these issues whilst protecting the internationally important wildlife within the river.


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This Management Report offers a means by which farmers can be supported to meet the challenges of farming the floodplain. It is designed to be a strategic, high level guide and may assist in the uptake of agri-environmental schemes and provide an opportunity for farmers to seek financial assistance to adapt their practices. For example, financial support (through Environmental Stewardship or Glastir) may be given to farmers to change land management practices where land is subject to repeated flood impacts (crop damage or soil loss) and/or land drainage issues. Similarly the restoration plans can be used as means of supporting farmers who wish to apply for grants or other funding streams, to fund adaptive floodplain land management e.g. woodland planting can be funded through grants schemes.


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Table 5-6 Summary of potential further work required to develop designs to accurately cost and implement each option

Action Feasibility assessment Design requirements

Rip

ari

an

Zo

ne M

an

ag

em

en

t Improve riparian zone

Determine the actual extent (e.g. width or length) of improvements required

Determine whether it will be necessary to undertake planting or just allow natural colonisation and succession to occur through appropriate management Evaluate the need for alternative land management arrangement (e.g. fencing, crossing points and livestock watering arrangements)

Produce a plan of the proposed improvements from which the actual extent of the works can be derived, enabling a detailed cost to be derived

Assis

ted

natu

ral

reco

very

Remove small weir

Evaluate the implications of factors such as: potential morphological adjustments, ecological constraints, access to the site and potential means of disposing of spoil

Produce a specification for the removal, or modification of the weir, including drawings illustrating how the work should be undertaken and how the site should look on completion

Remove bank protection or allow to degrade

Consider factors such as such as: ecological constraints, ground conditions, access to the site and potential means of disposing of spoil. The importance of these factors is likely to vary

Produce a specification for the removal of the bank protection, including drawings illustrating how the work should be undertaken and how the site should look on completion

Breach or remove embankments

Consider factors such as changes to flood risk, land management implications, ecological constraints, ground conditions, access to the site and potential means of disposing of spoil. The importance of these factors is likely to vary

Produce a specification for the breaching or removal of the embankment, including drawings illustrating how the work should be undertaken and how the site should look on completion

Realign channel to encourage deposition of mixed river gravel to create spawning habitat

Evaluate the implications of factors such as: ecological constraints, access to the site and potential means of disposing of spoil

Develop a site specific design including the height, slope, footprint and sediment grading

Sig

nif

ican

t re

sto

rati

on

Remove large weir (on main stem)

Evaluate the implications of factors such as other river uses, heritage value, flood control implications and potential morphological adjustments as well as ecological constraints, access to the site and potential means of disposing of spoil

Produce a specification for the removal, or modification of the weir, including drawings illustrating how the work should be undertaken and how the site should look on completion


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5.5 Delivery mechanisms and sources of funding

Whole river restoration plans are based on multi-partner working, time horizons suited to the nature and scale of each site’s problems and solutions (typically over 20 to 30 years), a negotiated settlement to any disagreements, and a best endeavours approach to implementation. Funds need to be secured to maintain best endeavours over time, including rolling bids to obvious budgets such as Environment Agency’s Flood and Coastal Risk Management (FCRM) capital works, European Funds, and Environmental Stewardship, but also opportunistic bids to a range of other funding sources including European programmes. Similar work from organisations, including ‘third sector’ partners such as the Rivers Trusts, has a vital part to play. Delivering the restoration vision will involve working in partnership with a range of individuals and organisations including:

• Welsh Dee Trust

• Angling Associations

• Welsh Water

• United Utilities

• National Farmers Union Cymru

• National Farmers Union

• Country Land and Business Association

• Forestry Commission

• Environment Wales

• The Wildlife Trusts. All stakeholder contributions that can help to deliver this plan will be welcomed. 5.5.1 Welsh Dee Trust

The restoration plans involve a range of different techniques which vary in the amount of work required. This means that implementation of approaches and funding requirements will vary between the different types of restoration actions. The Welsh Dee Trust (WDT) is one such delivery mechanism. The WDT is an independent environmental charity established to promote the protection, conservation and enhancement of the River Dee and all its indigenous species of fish, animals, birds and plants. It also aims to increase awareness and understanding of the management of water bodies and the wider environment2. Rivers Trusts generally rely on public funding, but many have successfully applied for European Union structural funds such as Interreg and Objectives One, Two and 5b or Lottery funds. They deliver major programs of physical works and practical river improvements in partnership with the Government Agencies. Rivers Trusts are a cost-effective means of delivering environmental, social and economic outputs with strong community stakeholder involvement. At present the WDT lists projects completed on the Llynor, Hirnant, Camddwr and Upper Ceidiog. 5.5.2 Water Framework Directive Improvement Fund

In 2011 the Government in England announced a £110m fund to improve the health of over 880 lakes, streams and other water bodies, whilst also helping to boost local involvement in caring for blue spaces. £92 million will be provided over the next four

2 More information available at: < http://www.welshdeetrust.com/> [Accessed on 04/02/13]


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years to remove non-native invasive weeds and animals, clear up pollution, and remove redundant dams, weirs, and other man-made structures so that wildlife can thrive in water catchments across England. An additional £18 million was allocated during 2011 to provide help to farmers to install measures such as buffer strips and fences to protect watercourses and other actions to prevent agricultural pollution, under the Catchment Sensitive Farming programme. 5.5.3 Diffuse Water Pollution Plan

A range of measures are being implemented to reduce diffuse water pollution in the catchment, these include:

• Reducing sediment supply to the river by enhancing riparian habitats along the river corridor

• Reduced sediment runoff from fields

• Reduced sediment runoff from livestock poaching

• Reduction of unconsented pollution incidents. These measures are described in more detail in the River Dee Diffuse Water Pollution Plan (England) and in the River Dee River Basin Management Plan. The Welsh Government also tasked the Environment Agency Wales to produce an all Wales Diffuse Pollution Action Plan to tackle sources on a wide range of diffuse water pollution; outlining solutions to address the problem in both rural and urban areas. The purpose of this was to address problems in the current round of River Basin Management Plans and feed into the second cycle of planning for the Water Framework Directive. Agri-environment schemes in Wales (Glastir) are now paying land managers to adopt resource protection measures such as nutrient and soil management and to introduce buffer strips. 5.5.4 European funding

The Innovation and Environment Regions of Europe Sharing Solutions (Interreg) are co-financed by the European Regional Development Fund (ERDF). It includes monies for water management, including:

• Improving quality of water supply and treatment, including co-operation in the field of water management

• Supporting integrated, sustainable and participatory approaches to management of inland and marine waters, including waterway infrastructure

• Adapting to climate change effects related to water management. The LIFE programme is the EU’s funding mechanism for the environmental improvement initiatives. LIFE projects support a wide range of water-related issues, such as urban water management, industrial wastewater treatment, river basin monitoring and improving groundwater quality. LIFE has co-financed over 3000 projects across the EU, equating to approximately €2.2bn to the protection of the environment. The European Fisheries Fund (EFF) provides grants for the development of a fisheries sector that is sustainable, profitable, well managed and internationally competitive. For example in November 2009 Afonydd Cymru announced that they had been successful in their bid for a grant from the European Fisheries Fund (EFF) (75% funding) and the Welsh Government (25% of the funding). The grant was


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awarded to enable the delivery of the “Environmental Improvements to Sustain Welsh Fisheries’ Project (EISWF), specifically for projects benefitting migratory fish by increasing their access to spawning areas through the improvement of water quality and river habitat restoration. Afonydd Cymru were successful in securing £1,304,235.80 over 4 years. The Welsh Dee Trust have completed 6 projects under this funding ranging from pool creation (Llynor), a fish pass (Hirnant), increase of parr habitat (Hirnant) and fencing to prevent bank erosion and siltation (Camddur). 5.5.5 Environmental Stewardship Schemes

The Environmental Stewardship schemes are likely to be an appropriate source of funding for this type of work, and are particularly appropriate to measures aimed at improving the riparian zone and giving the river more space by defining such land as buffer strips. Improvements to the riparian zone can also provide improved soil conservation, especially in arable areas. There are currently a number of levels of Stewardship in England:

• Entry Level Stewardship

• Organic Entry Level Stewardship

• Upland Entry Level Stewardship; and

• Higher Level Stewardship.

CAP reform means that Environmental Stewardship schemes in England are changing and the details of any new scheme are not yet known. The current Rural Development Programme for England ends in December 2013. The new programme is expected to start from January 2015 onwards3 (with new agri-environment agreements likely to start on 1 January 2016).

5.5.6 Glastir

In Wales, Glastir has replaced the existing agri-environment schemes. It commenced in January 2013 and will remain valid for the next few years. It pays for the delivery of specific environmental goods and services aimed at:

• Combating climate change

• Improving water management

• Maintaining and enhancing biodiversity. It is designed to deliver measurable outcomes at both a farm and landscape level in a cost effective way and consists of the following five elements:

• Glastir Entry (previously called All-Wales Element (AWE)) - a whole farm land management scheme open to application from all farmers and land managers throughout Wales

• Glastir Advanced (previously called Targeted Element (TE)) - a part farm scheme which runs alongside AWE. It is intended to deliver significant improvements to the environmental status of a range of habitats, species, soils and water. This may require changes to current agricultural practices.

3 More information is available at:

<http://www.naturalengland.org.uk/ourwork/farming/funding/transition2014-2020.aspx> [Accessed on 12/02/13]


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Financial support from the Welsh Government is targeted at locations where action will lead to the required result

• Glastir Commons (previously called Common Land Element) - designed to provide support for the delivery of environmental benefits on common land

• Agricultural Carbon Reduction and Efficiency Scheme (ACRES). A capital grant scheme available to farmers and land managers who hold an AWE contract. It is aimed at improving business and resource efficiency, and reducing carbon emissions of agricultural and horticultural holdings

• Glastir Woodlands (previously called Woodland Element) - designed to support land managers who wish to create new woodland and/or manage existing woodlands (see Glastir Woodlands Creation Scheme below).

Glastir is funded by the Rural Development Plan for Wales 2007-2013. This is financed by the Welsh Government and the European Union. 5.5.7 Catchment Sensitive Farming

In England Catchment Sensitive Farming is a partnership between the Environment Agency and Natural England, funded by Defra and the EU Rural Development Programme. In Wales, the initiative is run by Environment Agency Wales and funded by the Welsh Assembly Government (WAG). EAW led the partnership and CCW are continuing the support through Section 15 management agreement payments. The initiative delivers practical solutions to reduce diffuse pollution from agricultural land to protect water bodies and habitats. In both England and Wales the initiative provides resources for a dedicated catchment coordinator. Specifically, CCW is working with the Welsh Government, the Environment Agency Wales, the Snowdonia National Park Authority and farmers on a pilot project to try to reduce the amounts of diffuse pollution from farming reaching waters around LLyn Tegid in North Wales (in the Upper Dee). CCW will be working with farmers and other partners (in respect of protected sites) to ensure that diffuse pollution is tackled wherever this is a problem in Welsh rivers, lakes and wetlands. 5.5.8 Forestry Commission English Woodland Grant Scheme

The planting of riparian woodland may be supported by the English Woodland Grant Scheme (EWGS) administered by the Forestry Commission. This stream of funding has been designed to develop the co-ordinated delivery of public benefits from England’s woodlands. Grants are available to improve the stewardship of existing woodland and to promote and enable the creation of new woodland. 5.5.9 Glastir Woodland Creation Scheme

Under this grant scheme people can receive up to £9000 per hectare to plant trees, without loss of single farm payment. Creating a Welsh landscape rich in native trees and woods is vital to meet the challenges of a changing climate whilst also supporting the productive use of land. The Welsh Government has a target of creating 100,000 hectares of new woodland over the next 20 years. The scheme includes a planting grant over the first three years, an income foregone payment over 15 years and also a fencing payment of £3.15 per metre for new fencing. The rates vary depending on the type of trees planted and are higher for registered farmers.


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5.5.10 Catchment Restoration Fund (England)

The Department for Environment, Food and Rural Affairs (Defra) created the Catchment Restoration Fund to support this aim. A £28m fund, providing up to £10m each year, was allocated for projects to be delivered in 2012/13, 2013/14 and 2014/15. The fund supports work that aims to:

• restore more natural features in and around waters

• reduce the impact of man-made structures on wildlife in waters, or

• reduce the impact of small, spread-out (diffuse) sources of pollution that arise from rural and urban land use.

The Environment Agency administers the fund. The fund will run for three years. However the Government has announced that to complete existing commitments on projects there will not be an opportunity to run a third round of the fund in March 2013. The EA recognises there are many organisations that had been looking to a third round. Indeed there are many projects that did not receive funding in rounds one and two, anticipating a third round too. The Environment Agency will actively pursue and advise on alternative sources of funding for strong project proposals. 5.5.11 Partnership Projects in Wales

In Wales, the Environment Agency Wales is inviting proposals from organisations to deliver partnership projects that improve the ecology of the water environment. Examples of existing projects in the Dee Catchment include one by The Welsh Dee Rivers Trust which will organise and provide equipment for angling clubs to manage invasive plant species. Also, The Welsh Dee and Clwyd & Conwy Rivers Trusts are working with the Woodland Trust to restore stream side woodlands on the River Camddwr near Corwen.

5.6 Current examples of restoration schemes in the Dee catchment

During consultation a number of restoration schemes on tributaries of the Dee, which are outside the SSSIs boundary, came to light. One example was the restoration of a section of the Afon Camddwr, near Corwen. The channel had been historically modified, some sections were devoid of tree cover and in other sections trees had overgrown the channel. The Welsh Dee Trust undertook some restoration works on the river, including planting 800 trees donated by the Woodland Trust in areas devoid of trees, coppicing, fencing and removing rubbish. The Welsh Dee Trust has also removed a weir from Abbey Brook near Llangollen. As part of the European Fisheries Fund the weir was removed and replaced with a rocky ramp (Figure 5.1A and B). The Welsh Dee Trust also organise an annual ‘Big Dee Day’ where volunteers help tidy up the Dee collecting litter. This year they are organising another event in June called the Big Dee Day Invasives action. CCW currently have a Dee Invasive Non Native Species project officer post, and hope this will continue under NRW.


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Figure 5.1 Abbey Brook A) weir before removal and B) the rocky ramp post weir removal (Photographs provided by Mark Pierce, a Welsh Dee Trustee)

The EA are currently undertaking a feasibility study for the restoration of a tributary of the Dee near Chester. This would involve realigning a straightened section of the watercourse to enhance habitat for wildlife and help the water body achieve Good Ecological Status. An additional benefit may be reduction of flood risk of a nearby village.


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6 References

Environment Agency (2010) River Dee Catchment Flood Management Plan. Summary Report [pdf]. Available at: <http://a0768b4a8a31e106d8b0-50dc802554eb38a24458b98ff72d550b.r19.cf3.rackcdn.com/gewa0110brko-e-e.pdf> [Accessed on 04/02/13] Environment Agency (2012). Water for life and livelihoods. River Basin planning: summary of significant water management issues. Dee River Basin District [pdf]. Available at <http://www.environment-agency.gov.uk/static/documents/Research/deeswmidoc_1953937.pdf> [Accessed on 04/02/13] Environment Agency (2009) River Dee Basin Management Plan, Annex B Gurnell A.M. (1997) Channel change on the River Dee meanders, 1946-1992, From the analysis of air photographs, Regulated Rivers: Research and Management, 13: 13-26 Hatcher D. and Garrett H. (2008) Core Management Plan (including conservation objectives) for the River Dee and Bala Lake/ Afon Dyfrdwy A Llyn Tegid SAC, Report for Countryside Council for Wales Hill C.T. and Emery J.C. (2005) Fluvial Audit of the River Dee, Report UC0690, GeoData Institute Jacobs (2012) River Mease SSSI/SAC Restoration Plan. Report produced for Natural England and the Environment Agency JNCC (2013) Habitat account – Freshwater habitats [Online] Available at <http://jncc.defra.gov.uk/protectedsites/sacselection/habitat.asp?FeatureIntCode=H3260> [Accessed on 04/02/13] Piegay, H, Darby, S.E, Mosselman, E and Surian, N. (2005) A review of techniques available for delimiting the erodible river corridor: a sustainable approach to managing bank erosion, Rivers Research and Applications, 21: 773-789 Walling, D.E., Collins, A.L. and McMellin, G.K. (2002) Provenance of interstitial sediment retrieved from salmonid spawning gravels in England and Wales: A Reconnaissance Survey Based on the Fingerprinting Approach. A R&D Technical Report (W2-046/TR3) published by the Environment Agency. Research Contractor: Dept. of Geography, University of Exeter


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Appendix A Consultation report

The Consultation Report is provided as a separate supplementary report to this Management Report.

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