Restoring the River Axe Site of Special Scientific Interest and Special Area of Conservation River Restoration Plan Draft for comment - 7 December 2015 to 17 January 2016

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CONTENTS Chapter Page

Executive Summary

1

Aim of the restoration plan 1 Working with others 2 How to comment on the draft plan 3 Delivering the restoration plan 3

1 Restoration of the River Axe 5

1.1 Introduction 5 1.2 The need for restoration 7 1.3 A restoration vision 7 1.4 How can we deliver this restoration? 8 1.5 Our approach 8 1.6 How to use this plan 10 1.7 Who is this plan for? 11

2 The River Axe Site of Special Scientific Interest 12

2.1 Geology and hydrology 12 2.2 Ecology 13 2.3 Conservation objectives for the River Axe SSSI 13 2.4 Condition of the River Axe SSSI 14 2.5 Water Framework Directive objectives 16 2.6 Land use and land use change 17 2.7 Water quality 17 2.8 Flood risk 18 2.9 Invasive non-native species and disease 19 2.10 Influences on geomorphology and channel change 20

3 River sector descriptions 23

3.1 Summary of sector descriptions 23 3.2 Upper sector 25

3.2.1 Physical characteristics 26 3.2.2 Historical change 26 3.2.3 Geomorphological behaviour 27 3.2.4 Significant issues 27

3.3 Mid sector 29 3.3.1 Physical characteristics 30 3.3.2 Historical change 30 3.3.3 Geomorphological behaviour 31 3.3.4 Significant issues 31

3.4 Lower sector 33 3.4.1 Physical characteristics 35 3.4.2 Historical change 35 3.4.3 Geomorphological behaviour 36 3.4.4 Significant issues 36

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4 Channel modifications and restoration measures 38

4.1 Geomorphology and channel change 38 4.2 Impact of existing modifications 39 4.3 Potential restoration and management options 41 4.4 Summary of restoration options –management sheets 42

5 Consultation, actions and implementation 44

Figures

1 Map of River Axe SSSI/SAC 6 2 Geomorphological reaches within the SSSI/SAC as identified in

BBR 2004 24

3 Map showing upper sector SSSI units and geomorphological reaches

25

4 Upper sector length of each characteristic bank type 28 5 Map showing mid sector SSSI units and geomorphological

reaches 29

6 Mid sector length of each characteristic bank type 32 7 Map showing lower sector SSSI units and geomorphological

reaches 33

8 Lower length of each characteristic bank type 37 9 Remedial actions location plan 46 10 Decision making process for restoration plan actions related to

structures 52

Tables 1 Summary of condition of River Axe SSSI management units 15 2 Summary of influences on sediment and morphology in the Axe

catchment 21

3 Upper sector features summary 27 4 Mid sector features summary 32 5 Lower sector features summary 36 6 Assessment approach 40 7 Remedial priority issues 40 8 Summary of potential solutions. 42 9 Draft remedial action programme 43 10 Draft remedial action programme 45

Glossary 48

Annex 1 Management sheets – web link provided to access these during

comments phase 50

1 Weycroft Weir 2 Town Weir 3 Bow Bridge A35 blockstone weirs 4 Whitford Bridge 5 Whitford gauging station 6 Weycroft Bridge 7 Stoney Bridge and Axminster Flood Defence Scheme 8 Whitford blockstone weirs 9 Bank Revetments 10 Riparian zone river bank tree management 11 Riparian zone invasive non-native plant management 12 Riparian zone livestock management

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Annex 2 Decision making related to structures such as weirs and sluices

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Bibliography 53

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Executive Summary

The River Axe is designated as a Site of Special Scientific Interest (SSSI) under the Wildlife

and Countryside Act 1981 and as a Special Area of Conservation (SAC) under the

Conservation of Habitats and Species Regulations 2010. The SSSI also incorporates

Geological Conservation Review interest.

The UK Government’s ‘Biodiversity 2020’ strategy includes a commitment to ensure that at least 50% of designated SSSIs achieve ‘favourable condition’, (ie the site is being adequately conserved and is meeting its 'conservation objectives’) and that 95% of sites are maintained in ‘favourable or recovering’ condition by 2020.

The 2011 Natural England condition assessment (ECUS, 2011) of the River Axe SSSI

showed that the site is in unfavourable condition. The reasons for unfavourable condition

include physical modifications such as weirs, poor riparian habitat quality due to overgrazing

and invasive plants, diffuse water pollution and siltation.

For the River Axe SSSI, Natural England has identified a range of actions or ‘remedies’

required to get the river into favourable condition. The actions required include developing a

whole river restoration plan and initial implementation of actions. Other actions include

implementing a diffuse water pollution plan, catchment sensitive farming initiatives, and an

invasive species control strategy.

In addition, the European Water Framework Directive (WFD) requires all EU Member States to protect and, where possible, enhance the condition of all bodies of water. The Water Framework Directive requires protected areas including the River Axe Special Area of Conservation to be meeting their objectives by 2015 (or in cases where there are significant pressures to address, 2021 or 2027). The river is not currently achieving the required standard of Good Ecological Status (GES). As the River Axe is not currently achieving it’s SSSI or WFD objectives the Environment Agency, Natural England and others are obliged to undertake work to ensure that the required standards are achieved in the future. The development of a whole river restoration plan and its implementation (in combination with other actions) is required so the River Axe achieves its SSSI and WFD objectives.

Aim of the restoration plan

The aim of this strategic restoration plan is to identify high level river restoration or

enhancement actions to address the physical modifications to the River Axe which are

contributing to unfavourable condition. This includes the following specific objectives:

1. Determine the impacts of physical modifications on the geomorphology and ecology

of the river.

2. Provide an outline restoration plan for the river on a reach-by-reach basis, taking into

account immovable constraints.

3. Identify potential delivery mechanisms.

The catchment has a complex history of man-made changes, many of which have significant cultural, heritage and social values associated with them. The realistic aim for the Axe SSSI

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is to manage and restore as much dynamic function to the river as possible, within current immovable constraints in order to provide the conditions required for river wildlife to flourish. We are not aiming to restore the entire river to an unmodified state. This draft plan outlines the assessments made and the restoration options that have been identified to naturalise river processes, support catchment sensitive farming initiatives, encourage riparian management that favours biodiversity and implement an invasive species strategy. It provides a framework for the improvement in the physical habitat condition of the river over long timescales, and will inform future decision-making.

Working with others

Natural England and the Environment Agency are jointly responsible for leading

development of the strategic plan. However a range of interested parties and mechanisms

will also be involved in developing and implementing particular options - this requires

effective and positive engagement with landowners, land managers and stakeholders.

Natural England and the Environment Agency will take steps to involve relevant individuals

and representative groups in developing actions from this strategic plan. We will work with

the East Devon Catchment Partnership and other interested parties to take it forward, with

detailed discussions taking place with landowners and managers to develop reach specific

actions. Whilst some actions will be completed relatively quickly over the next few years,

other measures will take more time to develop, and be implemented over long timescales.

The detail of any restoration projects will be developed in conjunction with landowners and other stakeholders, in order to identify constraints and design appropriate restoration options. Permissions from landowners, Natural England and the Environment Agency will be required for restoration projects, all of which will be subject to a Habitats Regulations Assessment. Landowner participation is key to delivery and detailed discussions and agreement with landowners about specific river reaches is recognised as being an essential part of developing detailed restoration projects and undertaking site specific actions in coming years. The importance of agriculture to the rural economy is recognised and a valid consideration when developing river restoration projects. It is acknowledged that that restoration measures affecting land use may only be appropriate for certain locations, will require support (such as from Countryside Stewardship) and may be implemented over long time scales. Actions will only be taken forward once agreement has been gained from the relevant stakeholders, and will be carried out in close partnership to ensure effective delivery and viability of the solution. This plan will assist in the targeting and uptake of agri-environment schemes and provide an opportunity for farmers to seek financial assistance to adapt land management practices if required. The restoration plan may be used as means of supporting farmers who wish to apply for grants or other funding streams, to fund adaptive floodplain land management, for example woodland planting may be funded through grant schemes.

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How we will use your comments

Your personal information and comments are being collected by the Environmental Agency and Natural England. We will consider all comments received. Comments about factual accuracy will be checked and, where appropriate, incorporated into the final river restoration plan for the River Axe. Those that contribute thoughts, opinions on the report or proposed actions will be logged and compiled as an Annex in the final plan, rather than incorporated into the main body of the document. These will then be available to inform future discussions between the East Devon Catchment Partnership and relevant owners, and highlight areas of particular concern or interest as specific restoration projects are taken forward. On the comments form there is an opportunity to indicate if you are requesting that your

response is not published in the summary of responses. If we receive a request under the

Freedom of Information Act 2000, we may be required to provide a copy of your response in

future, but will not include any personal information.

Delivering the restoration plan We will use the comments received to shape a final restoration plan that can be implemented by working in partnership with landowners and managers and relevant organisations. This will be used from 2016 onwards to guide the delivery of restoration projects on the ground to improve the habitat along the river. It will also inform decisions made about river management activities including targeting of Countryside Stewardship and catchment sensitive farming. Restoration actions are suggested in this report as a means to achieve favourable physical habitat condition of the SSSI and SAC. Please note that this report identifies a suite of

How to comment on the draft plan The Environment Agency and Natural England invite you to comment on this draft plan. We want to hear your views, suggestions, concerns, constraints, so together we can work up and deliver a final agreed action plan. The draft river restoration plan is available for comment at http://www.therrc.co.uk/sites/default/files/files/Designated_Rivers/Axe/axe_v1.pdf from 7 December 2015 to 17 January 2016. Two copies of the draft plan, and comments forms, are also available for viewing at Axminster Library, South Street, Axminster Devon EX13 5AD. Please send your comments to devoncornwallenquiries@environment-agency.gov.uk, or to Devon and Cornwall Enquiries Team, Environment Agency, Sir John Moore House, Victoria Square, Bodmin, PL31 1EB. Any questions during the comments period? We recognise this is a very technical report and are happy to answer any questions you have about the draft report between 5-23 December 2015 and 4-17 January 2016. Please contact Mary-Rose Lane at the Environment Agency on 020 302 52367.

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potential actions based on a strategic assessment of the river. All the potential actions require further detailed planning and permission from landowners, Natural England and the lead flood authority and/or Environment Agency. In the short term we envisage that work will be done with interested parties to implement agreed restoration activities and to gather evidence of the benefits. This may be initiated by the East Devon Catchment Partnership, or individual organisations or owners. Over time, restoration of the river will improve it for the species and habitats that depend on it, and help the river become more resilient to future extremes of flow and temperature. This should in turn benefit the people who live and work along the rivers.

Example of features created by dynamic river processes, on the River Yarty outside the SSSI

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Chapter 1. Restoration of the River Axe 1.1 Introduction The Axe catchment, situated within Somerset, Dorset and Devon, covers approximately 307km² with the combined length of the Axe and its four main tributaries totalling some 59 km, in addition to many minor tributaries and feeder streams. 13 kilometres of the lower River Axe was designated as a Site of Special Scientific Interest in 1999. The SSSI extends from the confluence with the Blackwater Stream down to the tidal limit near Colyford. The primary reason for designation is the river habitat, as a good example of unusually active lowland river types. The river habitat supports a number of associated plant, fish and invertebrate communities and species. The river was also designated as a Special Area of Conservation under the European Habitats Directive of 2002. Over its length, the SSSI displays a river environment modified by centuries or human activity, whilst still retaining many of its natural geomorphological and important ecological features.

River Axe, showing ranunculus beds, bank side willow scrub, and invasive Himalayan balsam in the riparian zone

This chapter introduces:

The River Axe catchment, and a vision for the future of the River Axe SSSI

The River Axe Restoration Strategy Assessment approach

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Figure 1 Map of River Axe SSSI/SAC

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1.2 The need for restoration

The River Axe is regarded as being a relatively good, unmodified example of three lowland

river types but nevertheless is affected by a number of pressures. The Common Standards

Monitoring of the River Axe SSSI (ECUS 2011) showed that the site is in unfavourable

condition. Reasons for this include physical modifications such as weirs and bankside

revetments, poor riparian habitat quality due to overgrazing and invasive plants, diffuse

water pollution and siltation.

For the River Axe SSSI, Natural England has identified a range of actions or ‘remedies’

needed for the river to achieve favourable condition. These actions include developing a

river restoration plan, and initial implementation of actions. Other actions include

implementing a diffuse water pollution plan (Environment Agency/Natural England 2014)

catchment sensitive farming initiatives, and an invasive species control strategy (Newman,

2012). The river restoration actions are addressed in this plan, with cross references to

other initiatives where relevant.

Returning SAC rivers such as the Axe to ‘favourable condition’ is a requirement of the EU

Habitats Directive and contributes to England Biodiversity Strategy Targets. The River Axe

SAC has a number of measures attributed to it including a ‘river restoration programme for

protected areas’ in the current River Basin Management Plan for the South West

(Environment Agency 2014). Development of the river restoration plan and its subsequent

implementation will help improve the status of the river, contributing to achieving Good

Ecological Status as required under the Water Framework Directive.

1.3 A restoration vision Restoration planning involves generating a challenging ‘vision’ of desirable restoration measures. This ‘vision’ is based on removing artificial constraints to the rivers’ ability to show characteristic habitat form and function for the benefit of the plants and animals typical of the river type. The proposed vision for the Axe is to ensure the continuance of the current dynamic nature of the river. We will seek opportunities to ameliorate artificial constraints that limit the physical form and natural biodiversity of the SSSI and take active steps to manage, protect and enhance the rivers’ ecology. The restored River Axe will display:

A channel and floodplain that is morphologically dynamic and allowed to develop and

retain a range of natural features with their associated biodiversity.

A channel and bank flora and fauna representative of this river type; with non-native

invasive species being actively controlled.

Wildlife passage within the channel enabled, and impacts on this and river function reduced or mitigated through appropriate alteration or removal of artificial modifications such as weirs, bridges and revetments.

No new modifications that have adverse impacts on biodiversity or hydromorphology

of the catchment.

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Water quality and quantity that sustains river biodiversity and river and floodplain

form and function.

River and floodplain management that is sympathetic to the dynamic

geomorphological nature of the river and the existing rich biodiversity of the SSSI.

1.4 How can we deliver this restoration?

Through appropriate information gathering, wide consultation and engagement with affected parties leading to clear decision-making.

By maintaining those reaches already in favourable condition by a continuing vigilance and by regulating matters that influence water quality, quantity and river channel and bank works.

By allowing the natural recovery of physical features and encouraging ongoing positive management of the riparian corridor and wider floodplain.

By taking opportunities to modify or remove artificial features that constrain the natural processes of the river where these degrade the ecological quality of the SSSI, whilst being aware of the wider needs to protect property, landscape, food production, social and cultural values.

Actively undertake and encourage initiatives to control invasive plants such as Himalayan balsam and promote habitat diversity by planting riverbank trees and woodland blocks in selected areas.

1.5 Our approach

We developed this draft plan by:

Identifying key issues based on their geomorphological and ecological impact on favourable condition; using maps, consultation, local knowledge, and existing reports, (i.e. Babtie, Brown and Root 2004) that provide the wider geomorphological context and evidence that underpin this plan.

Field-survey of each significant structural modification mapping and recording the type, location and baseline geomorphological and ecological characteristics at each site. All modifications were assessed in the field for their overall impact on favourable condition and for the need for further assessment to identify options for restoration.

Desk-based evaluation for each site and key influences identifying potential options for restoration. For each significant structure or key activity, a summary of the impacts, potential restoration options, constraints, priority and next steps is presented.

Development of a draft plan of restoration actions preparing a programme of actions, timescales and potential funding for wider comment, refinement and agreement.

The river restoration plan is intended to provide a framework for the improvement of the physical habitat of the River Axe SSSI/SAC to 2050.

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Understanding the modifications of the River Axe SSSI/SAC.

Assessment of modifications and management practices can help to:

Restore favourable condition to the River Axe SSSI based on an understanding of ecology and geomorphology

Restore sediment connectivity along the river channel

Restore biological continuity e.g. fish passage

Maximise the potential for assisted natural recovery of river habitat

Identify and prioritise opportunities for restoration

Encourage management actions that promote more natural river process and biodiversity

Identify opportunities for natural flood risk management approaches to benefit people and wildlife

Two views of the River Axe SSSI showing features that illustrate the SSSI quality and what could be possible throughout more of the river catchment - large woody debris, in-channel bars, well vegetated river banks providing a range of in-stream and riparian habitats supporting

a range of wildlife.

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1.6 How to use this plan

The plan’s structure is explained below to help you navigate around it.

Chapter Content Recommendation for use

1 Restoration of the River Axe

Explains the purpose of this plan.

Use this section to understand: why this restoration plan for physical modification has been developed for the SSSI; how it fits into the vision for the Axe SSSI; and our approach to the assessment.

2 The River Axe Site of Special Scientific Interest

Briefly describes the geomorphological and ecological context for the assessment of modifications and restoration potential.

Use this section to obtain a background understanding of the River Axe SSSI. Refer to BBR (2004) and ECUS (2011) for more detail.

3 River sector descriptions

Splits the SSSI into 3 sectors, describing their physical character, historical change and significant issues.

Use this section to obtain a background understanding of the geomorphology, flows and artificial influences within the 3 sections of the River Axe SSSI.

4 Channel modifications and restoration measures

A condition summary of the SSSI, identifies the key elements impacting on the SSSI. Basic assessment sheets for each of the priority impacts give a summary understanding of the nature of individual modifications and the options for restoration.

Use this section for a broad understanding of key potential impacts of modifications in the SSSI, and for a user friendly understanding of the potential risks, opportunities and next steps for each of 9 specific impacting structures and 3 impacting generic habitat management issues.

5 Consultation, actions and implementation

Gives our approach to consulting with river managers and those interested in river restoration related to modifications in the SSSI. Gives a rationale for prioritising action and identifies key delivery mechanisms and next steps.

Use this section to help implement opportunities for restoration within a catchment context and a strategic framework.

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1.7 Who is this plan for?

This plan is primarily intended for use by river managers or asset owners who are planning river restoration related to modifications in the SSSI. The plan is designed to be simple and user-friendly. It does not require specialist technical knowledge of geomorphology or ecology as this is available in technical reports referenced in this plan if needed. Where these are not published, the Environment Agency or Natural England can make these available for future project planning.

It is a stand-alone plan for supporting action towards river restoration by management of modifications in the SSSI. It provides a simple background to the catchment and a way forward for restoration of individual physical modifications within an overall strategic plan. The high level management sheets for each structure in Chapter 4.4 provide a set of simple tools for supporting and making decisions.

This draft plan aims to inform and provide discussion about the possible options that could be implemented along the River Axe SSSI/SAC to improve the natural function of the river, and increase the extent of habitats for aquatic and terrestrial wildlife. To achieve the aims of this plan the Environment Agency and Natural England want to communicate positively and effectively with landowners, structures owners and managers, and other representative groups.

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Chapter 2. The River Axe SSSI

2.1 Geology and hydrology The River Axe SSSI starts upstream at the Axe confluence with the Blackwater stream on the 43-metre contour AOD and from here meanders to the sea through a wide floodplain characterised by improved dairy pasture. The contrasting patterns of meander formation are of geomorphologic interest and of national importance. The geology in the lower reaches of the Axe consists of silty mudstones with small outcrops of laminated shales and limestones. The middle reaches of the Axe are underlain by thinly bedded limestones and silty mudstones. Throughout, the valley floodplain is filled with alluvium with exposed loam adjacent to the river displaying clayey soil rich in organic matter. The underlying geology of the riverbed is alluvium with areas of valley gravel, clay, shale and marl. At the downstream end of the SSSI the river reaches the tidal limit at the 3m contour, a fall of 40 metres with an average gradient of 1:460. River flow recorded at Whitford Bridge gauging station since 1964 shows a mean daily flow of 5.11 cumecs with a Q95 of 1.24 cumecs9. The maximum-recorded daily flow of the Axe is 144.72 cumecs with a maximum instantaneous flow of 244 cumecs. Hydrological records indicate that base flow is high reflecting the soils and subsoil conditions. Abstraction for public water supplies, industrial and agricultural purposes reduces the natural river flows, which is locally increased and nutriently enriched by effluent returns from sewage treatment plants.

Flooded meanders showing floodplain features and river sinuosity between Axminster and Cloakham

This chapter provides an overview of our findings on the geomorphology, river

flows and ecological context of the Axe SSSI.

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2.2 Ecology Classification of the lower Axe based on vegetation communities places it in a group of shallow gradient lowland rivers characterised by base rich waters with diverse flows. The SSSI supports an exceptionally diverse aquatic and marginal flora. A variety of plant communities are represented, including in the higher reaches a community type usually confined to sandstone catchments in Scotland. In the lower reaches, this gives way to a community more typical of rivers flowing slowly over clay. The lower River Axe was designated as a Site of Special Scientific Interest in 1999. The primary reason for designation is the river habitat, as a good example of unusually active lowland river types, and for its fluvial geomorphology (river processes). The river habitat also supports a number of nationally important associated plant, fish and invertebrate communities and species. The river was additionally designated as a Special Area of Conservation under the European Habitats Directive in 2002. The stretch of river designated as an SSSI has a rich and diverse range of plant communities represented, this is in part due to the quality and extent of natural physical features such as riffles, pools, depositional exposed gravels and meanders that are present. Submerged aquatic plants include stream water-crowfoot, river water-crowfoot and the nationally scarce short-leaved water-starwort. Other plant species recorded include perfoliate and fennel pondweed, amphibious bistort, brooklime, horned pondweed and spiked water-milfoil. Emergent and marginal plants include reed canary-grass, branched bur-reed, reed sweet-grass, water mint, marsh woundwort and water forget-me-not, flowering rush and great yellow-cress. The flora becomes slightly richer in the lower reaches and includes small and broad-leaved pondweed, various-leaved water-starwort and common

reed mace. The River Axe is also designated as a Special Area of Conservation under the Habitats Directive for the following habitats and species:

Watercourses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation. (Rivers with floating vegetation often dominated by water-crowfoot)

Bullhead Cottus gobio

Brook lamprey Lampetra planeri

Sea lamprey Petromyzon marinus

The river and adjoining land is also important for a wider range of wildlife. Fish of importance in a European context include Atlantic salmon, with species such as brown and sea trout, sea and brook lamprey and thick-lipped grey mullet well represented. Riparian habitats are also important for birds such as kingfisher, dipper, reed bunting, grey wagtails, green sandpiper and little egrets. Mammals such as otter and water vole are present and many other common and scarcer wildlife species flourish, such as white-legged damselfly and the banded demoiselle and a nationally rare alder fly, two nationally unusual caddis fly species and the uncommon medicinal leech. Many of these species are cited as key features within the designations.

2.3 Conservation objectives for the River Axe SSSI Common Standards have been agreed for setting conservation objectives, and assessing the condition of freshwater SSSIs and SACs against those objectives (JNCC 2014).

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Conservation objectives define the desired state for each SSSI site in terms of the features for which they have been designated. When these features are being managed in a way which maintains their nature conservation value, then they are said to be in ‘favourable condition’. Conservation objectives are based on the environmental integrity of the river habitat to support the characteristic flora and fauna of the habitat type. Integrity is defined in basic terms by a range of chemical, hydrological and physical attribute targets (some quantitative, some descriptive) considered to represent ‘favourable condition’. These targets are encapsulated in a ‘Favourable Condition Table (NE, 2009) for the River Axe. The conservation objectives as set out in the FCT for the Axe include targets related to maintaining (or restoring where it is currently below standard) the following:

Habitat extent (rivers and streams);

Characteristic flow regime;

Water quality;

No artificial barriers significantly impairing sediment or wildlife migration;

Predominantly unmodified and characteristic channel form;

No excessive siltation levels;

Appropriate wildlife species composition and abundance; and

No impact on native biota from alien or introduced species.

2.4 Condition of the River Axe SSSI The condition of all SSSIs in England, including the River Axe, is assessed by Natural England against site-specific targets which are set out in a favourable condition table. A SSSI unit is assessed to be in ‘favourable condition’ if the SSSI is being adequately conserved and is meeting its targets. The most recent condition assessment of the Axe SSSI took place in 2011 (ECUS, 2011). None of the survey sites were recorded as being in ‘favourable’ status for all of the parameters assessed, and none were found to be universally ‘unfavourable’. The overall assessment was that the Axe SSSI is in unfavourable condition. A summary of the current condition of the SSSI management units is given in Table 1. The latest condition assessment of the River Axe describes the condition of the site as ‘unfavourable declining’ because of:

Weirs, dams and other structures

Water pollution - agriculture/run off

Water pollution - discharge

Non-native Invasive species

The 2014 River Axe SAC Site Improvement Plan (River Axe SIP) states that weirs, dams

and other structures prevent natural hydrological processes acting, limiting natural habitat development. It recommends that this pressure should be addressed through completion of a strategic river restoration plan. This document implements that recommendation.

The actions included in this restoration plan will, in combination with other plans already being implemented to control invasive species (Newman 2012), and reduce diffuse water pollution (Environment Agency/Natural England, 2014), contribute to achieving the targets for favourable condition of the River Axe SSSI under the Biodiversity 2020 strategy.

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Table 1 Summary of condition of River Axe SSSI management units (Data from Natural England online summary site condition data available by opening unit number hyperlinks)

Unit Unit name Condition Habitat Reasons for failure Action in place Action required

1 DORSET SECTION Unfavourable - Declining

RIVERS AND STREAMS

Agriculture - overgrazing, water pollution - agriculture/run off, lack of corrective works - inappropriate pest control, inappropriate weirs dams and other structures, siltation

CSF, DWP plan, invasive species control

RDP CAP 2014-2020, works notice, river restoration

2 DEVON BORDER TO RIVER YARTY CONFLUENCE

Unfavourable - Declining

RIVERS AND STREAMS

Agriculture - overgrazing, water pollution - agriculture/run off, inappropriate weirs dams and other structure, inappropriate pest control, inappropriate weed control, other - other - specify in comments

CSF, DWP plan, invasive species control, AMP investigations

RDP CAP 2014-2020, works notice, fisheries enhancement project, river restoration

3 RIVER YARTY CONFLUENCE TO AXE BRIDGE

Unfavourable - Declining

RIVERS AND STREAMS

Agriculture - overgrazing, water pollution - agriculture/run off, inappropriate weirs dams and other structure, lack of corrective works - inappropriate pest control, siltation

CSF, DWP plan, AMP investigations, invasive species control, implement AMP scheme

RDP CAP 2014-2020, works notice, river restoration

4 AXMINSTER GEOMORPHOLOGY

Favourable EARTH HERITAGE

N/A

5 WHITFORD GEOMORPHOLOGY

Favourable EARTH HERITAGE

N/A

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2.5 Water Framework Directive objectives The Water Framework Directive is European legislation aimed at improving the management of rivers, coasts and estuaries to achieve ‘Good Ecological Status’ or ‘GES’. This is defined by the chemical, biological and physical qualities of the river. Under the European Water Framework Directive (2000/60/EC) http://eur-lex.europa.eu/legal-

content/EN/TXT/?uri=CELEX:32000L0060, the ecological status of a surface water body is assessed according to:

The condition of biological elements, for example fish, benthic invertebrates and other aquatic flora;

Concentrations of supporting physico-chemical elements, for example thermal conditions and concentrations of oxygen, ammonia and nutrients;

Concentrations of specific pollutants, for example copper and other priority substances; and

The condition of the hydromorphological quality elements, including morphological condition and hydrological regime.

Ecological status is recorded on the scale of high, good, moderate, poor or bad. 'High' denotes largely undisturbed conditions and the other classes represent increasing deviation from this natural condition, otherwise described as a 'reference condition'. The ecological status classification for the water body, and the confidence in this, is determined from the worst scoring quality element. This means that the condition of a single quality element can cause a water body to fail to reach its WFD classification objectives. Chemical status is assessed by compliance with environmental standards for chemicals that are listed in the Environmental Quality Standards Directive (2008/105/EC) http://eur-

lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32008L0105. These chemicals include priority substances, priority hazardous substances, and eight other pollutants carried over from the Dangerous Substance Daughter Directives. Chemical status is recorded as 'good' or 'fail'. The chemical status classification for the water body is determined by the worst scoring chemical. The Water Framework Directive requires protected sites including Special Areas of Conservation to be meeting their objectives by 2015 (or in cases where there are significant pressures to address, 2021 or 2027). For SSSIs the targets for Favourable Condition can be more stringent than for WFD due to the particular requirements of the wildlife or habitats at these sites and the WFD states ‘where more than one objective relates to a given body of water, the most stringent shall apply’. The River Axe SSSI is located in water body GB108045008870 (Axe). The water body is currently classed as being overall at Poor Ecological Status. Overall biological quality is classified as poor, chemical quality as moderate and hydro-morphological quality as not high. This means that the Environment Agency, Natural England and others are obliged to undertake work to ensure that the required standards are achieved in the future. The River Axe SAC has a number of measures attributed to it including a river restoration programme for protected area in the current River Basin Management Plan for the South West. Development of the river restoration plan and its subsequent implementation will therefore help improve the status of the river, contributing to achieving Good Ecological Status.

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2.6 Land use and land use change There are approximately 1,000 individual farm holdings in the catchment which cover around 36,300 hectares (88 %) of the catchment area. A comparison between AgCensus returns between 2000 and 2010 clearly illustrates intensification across the catchment for cattle, sheep, maize and temporary grassland (Natural England 2015). Land adjacent to the watercourses of the catchment is generally agricultural grade 4, due to the presence of clay in the soil which impedes drainage. This land provides rough pasture with fertiliser and field drains employed to help maintain the land (Sweet 2004).

Britain’s soils, seasonality and climate provide the natural ingredients for a productive farming sector both now and in the future. As population grows and climate potentially changes, there could be an increased dependency on agricultural land for food production. It is therefore important to recognise the importance of current and future agriculture and food production within the Axe catchment. The challenge in the 21st century is to increase productivity, maximise output, minimise inputs, achieve environmental sustainability and adapt to a changing climate. Changing farming practices, particularly the increase in arable farming, have been linked an increase in fine sediment (silt) delivery to watercourses (BBR 2004). Many farmers have already taken steps to minimise pressures on the water environment through the uptake of best practices via initiatives like Catchment Sensitive Farming. However impacts cannot be eliminated entirely and it remains a challenge to find a balance between achieving favourable condition/good status and maintaining agricultural production. New technology and farming techniques have an important role to play in future sustainable food production. The importance of agriculture to the rural economy is recognised and a valid consideration when planning river restoration. It is acknowledged that measures affecting land use will require support (such as from Countryside Stewardship) and may only be implemented over long time scales. Further information about the catchment including landscape, cultural heritage and recreation can be found in the fluvial audit (BBR 2004 B) and in the Pollution Risk Assessment for the Axe Catchment (Natural England 2015).

2.7 Water quality The 2011 condition assessment of the River Axe SSSI found the site to be in unfavourable condition for a number of reasons, including suspended solids and phosphates. The Axe is also classed under the WFD as having a moderate chemical status. Consequently the River Axe diffuse water pollution plan has been developed for the site to assess water quality pressures and management options. In 2014 the Westcountry Rivers Trust (WRT) carried out a detailed water quality risk assessment for the River Axe SSSI on behalf of Natural England. They assessed catchment wide pollution risks and develop a source apportionment model for the catchment. The objective was to review all the available evidence and to present this information in a way to inform the Diffuse Water Pollution Plan (DWPP) plan and future catchment management initiatives. The resulting source apportionment report (Natural England 2015) should be referred to for detailed information on land use and diffuse pollution risks in the catchment. The risk assessment and previous investigations identified specific pressures from suspended sediments and phosphorous. The DWPP and the WRT assessment will help Natural England, the Environment Agency and key partners to decide what, where, how and when to target efforts to improve water quality in the River Axe SSSI/SAC.

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Physical habitat modifications affect the ability of a river to convey sediment, and where combined with elevated inputs of sediment can lead to the river bed becoming excessively silty. This reduces the availability of clean coarse sediment, which is required by salmon, bullhead and lamprey to spawn. Elevated levels of silt also mean that water crowfoot is more prone to being washed out in high flows. A reduction in the amount of sediment and phosphates entering the river, combined with restoration of river geomorphology will therefore improve the condition of the river for the habitats and associated species it supports. Measures such as planting riparian buffer strips and blocks of trees should have benefits both for water quality and the physical habitat of the River Axe, and will help deliver the aims of the DWPP and this restoration plan.

2.8 Flood risk The European Floods Directive http://ec.europa.eu/environment/water/flood_risk/ requires flood risk management plans to be produced by December 2015. Flood risk management plans highlight the hazards and risks from rivers, the sea, surface water, groundwater and reservoirs and set out how Risk Management Authorities (RMAs) will work together with communities to manage flood risk. A South West Flood Risk Management Plan (SWFRMP) was produced for consultation in October 2014. The draft FRMP sets out proposed measures to manage flood risk in the south west river basin district from 2015. It also looks at how to improve the environment and includes links with River Basin Management Plan objectives. The River Axe is part of the East Devon catchment. According to the SWFRMP there are many sources of flood risk within this catchment. The main risk of flooding is from rivers, sea and surface water. The catchments of the Otter, Sid, Axe and Lim are very steep and are susceptible to short duration intense rainfall. There has been a history of intense rainfall causing widespread surface water flooding of small communities and isolated properties.

The River Axe generally responds to rainfall, though more slowly than the other East Devon rivers. The flood peaks of the River Axe reduce as they reach wide floodplain, but the river is often slow to recede in its lower reaches. The greensand geology is important in storing and slowly releasing groundwater into the tributaries of the Axe, maintaining flow through dry periods. The River Axe SSSI/SAC is entirely within the 1% annual probability flood extent. The Axe estuary is influenced by both fluvial and tidal flooding. However, flooding is one of the natural river processes that are important in maintaining the conservation status of the site. The Axminster area includes both the town and the floodplain of the River Axe. Although the majority of Axminster is on higher ground, some properties and industrial units along the north west side of the town near Stoney Bridge are located within the floodplain of the River Axe. Currently flood warning times are less than two hours from the River Axe in Axminster. Flood defences provide some protection to properties at risk. An earth embankment on the right bank provides was designed to provide a 1 in 60 year standard of protection, in reality this is now estimated to be a 1 in 20 year standard of protection. The railway embankment and stone revetments on the left bank provide a 1% annual probability standard of protection, although these were not designed as formal flood defence assets. These structures interrupt the connectivity of the river and floodplain, so are considered in this plan.

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Seaton is at risk of flooding from combined tidal and fluvial flood events from the Axe estuary with the main source of flooding from the sea. The main source of future flood risk in Seaton will continue to be tidal flooding from the Axe estuary. The SWFRMP has been developed alongside the River Basin Management Plan so that opportunities for flood risk improvements can integrate water and biodiversity objectives wherever possible. The SWFRMP objectives for the East Devon catchment include the following environmental objectives relevant to this restoration plan:

Achieve WFD objectives through flood risk management

Protect designated nature conservation sites 117 specific flood risk management actions are proposed including a number that are directly relevant to the river restoration plan. The following actions may provide benefits both for flood risk and the River Axe SSSI.

Ensure that flood defence consenting promotes restoration of meanders where appropriate, and allows the river to reclaim floodplain.

Investigate if embankments can be reduced where doing so would provide a flood risk benefit.

Identify locations with the potential to improve land management and land use to benefit flood risk management.

Consider ways of reconnecting the River Otter and River Axe to their floodplains to utilise flood storage and reduce risk to people.

Investigate, with partners, locations along the Axe estuary where improving connection to the floodplain could benefit biodiversity and reduce the risk of flooding to Seaton.

Measures such as reconnecting the river and floodplain, allowing natural river movement and setting back of embankments can have both flood risk and habitat restoration benefits. Opportunities will be sought to take forward projects that implement SWFRMP actions and river habitat restoration. The Exeter to Yeovil railway line bisects the Axe floodplain, creating a barrier to natural flood flow paths through the catchment as far south as Whitford and also in places storing water during flood events. This relationship between the railway embankments and flood risk is the subject of an ongoing study by Motts MacDonald for Environment Agency, Network Rail and Devon County Council. Any findings and projects that develop from that will need to be considered in relation to the favourable condition of the designated sites as well as business continuity and flood risk benefits.

2.9 Invasive non-native species and disease Himalayan balsam is extensive on the banks of the River Axe. Himalayan balsam out competes native riparian plants during the summer retarding their growth. The Himalayan balsam then dies back in the winter leaving the river channel margins free from vegetation which increases the vulnerability of the riverbanks to erosion. Diseased alders suffering from Phytophthora root disease are also extensive within the Axe catchment. To try to tackle the problem of non native invasive plants in the catchment, Natural England commissioned an Invasive Alien Plant Species Control Programme in 2012 (Newman 2012). This has since been incorporated into the River Axe Improvement Plan:

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http://publications.naturalengland.org.uk/file/6572555716526080). The Axe Invasives Project started soon after and is now in its third year working on the ground to control Himalayan balsam, Japanese knotweed and giant hogweed.

2.10 Influences on geomorphology and channel change

The 2005 catchment geomorphological appraisal (BBR 2014B) assessed influences on the sediment and morphology in the Axe catchment in detail. The influences on sediment and morphology identified are summarised in Table 2.

Natural geomorphological changes in the catchment have predominantly taken the form of changes in channel planform along the River Axe, primarily though the growth and cut-off of meanders. There is little documentation relating to the specific geomorphological impacts of hydrological events. While many of the bend changes recorded are likely to have been encouraged by flood events, they may also have occurred as a result of the gradual but progressive growth of bends which is typical of meandering rivers. A number of additional channel changes along the Axe were initiated by human activity. The river channel at Chard Junction was completely realigned sometime after 1891, possibly to facilitate industrial development in this location. At Westford Mill, downstream from Chard Junction a 400m section of river channel was excavated prior to 1891 in conjunction with the development of the mill. Field evidence indicates that this channel now conveys a greater quantity of flow that the original channel. In addition a number of bends were also removed or shortened during construction of the railway in the mid-nineteenth century.

The majority of the Axe catchment is largely unprotected from flooding; although major flood defence schemes are in place at Axminster, Stafford Brook and Seaton. There is little regular maintenance on the main rivers of the Axe catchment and any maintenance operations are only conducted where it is deemed absolutely necessary, such as gravel removals at Stoney Bridge about every three years. River channel modification ranging from piecemeal bank protection to extended sections of channel re-sectioning or realignment can alter both morphological diversity and the behaviour of the river channels. Channel re-alignment and re-sectioning has been conducted in several locations in the catchment. In these locations the channel morphology is often, but not always, simplified. The impacts of channel modification include reduced bed diversity, loss of natural bank materials and a reduction in gravel bar extents. The railway line follows the flat land in the floodplain for approximately 25km of the Axe catchment, south from Crewkerne, including the SSSI reaches from Broom before heading westwards at Whitford towards Exeter. The line is frequently raised on embankments running parallel to the river, and bridges the river three times through the length of the SSSI. This influence on river and floodplain processes since 1860 has not been significantly studied. However the modelling study currently underway for the Environment Agency, Network Rail and Devon County Council (Environment Agency River Axe scenario testing – Project no. IMSW001762) may provide more understanding of sediment transport and floodplain development as a consequence of the embankments in particular. Once this work is better understood any projects that develop from it will be required to contribute to restoring favourable condition of the SSSI and SAC.

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Table 2 Summary of influences on sediment and morphology in the Axe catchment (BBR2004B)

Time

Pre 1900 1900s-1940s

1950s 1960s 1970s 1980s 1990s 2000s

Floods Large floods in 1875, 1881 and 1894

Floods on 6 Feb 1900, 19 Dec 1909 and 17 Jul 1926

Flood in Dec 1965 with 2.5% probability. Flood Jul 1968

Dec 1985 Dec 1992

Capital works Localised realignment of the River Axe during construction of the railway along the Axe valley

Construction of fish passes at high weirs

River maintenance Ad hoc protection and channel works by landowners

Sympathetic approach to bank protection promoted by Environment Agency

Channel change (historic mapping)

Meander growth and occasional cut-off

Land use change (agriculture)

Nutrient application

Increase in stocking densities

Land drainage improvements

Increase in maize cultivation

Decline in improved grassland

Land use (minerals)

4 active quarries in catchment

Sand and gravel extraction at Chard Junction and Kilmington

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The BBR 2004 Geomorphological Appraisal identified the following key issues:

High volume of fine sediment supplied through a combination of bank erosion caused by channel weathering; invasive species and livestock poaching together with field drains and surface runoff from arable land.

Channel modifications such as bank protection; channel re-alignment; re-sectioning culverting and weir construction lead to reductions in channel morphological diversity inhibit natural geomorphological processes and in some instances, such as weirs, inhibit the passage of migratory fish species.

Channel planform changes and associated bank erosion along the River Axe are in part a reflection of the natural behaviour of meandering rivers. However, localised channel modifications such as bend removal, channel re-alignments and bank protection conducted throughout the last 200 years, have complicated the natural behaviour of the river channel. It is therefore extremely difficult to determine the extent to contemporary river behaviour is natural or a result of the anthropogenic interference. It is likely that channel activity represents a combination of natural and artificial influences. Further anthropogenic interference may lead to an unpredictable and undesirable channel response.

Himalayan balsam is extremely widespread in the catchment. The detrimental effect of this plant on riparian vegetation and riverbank stability is contributing to the transfer of sediment, particularly fine material, to the river channel.

For a more detailed description of catchment influences, geomorphological processes and key issues affecting the River Axe refer to BBR 2014B. This is available at http://www.therrc.co.uk/designated-rivers. Click on the word ‘Axe’ on the map to access the documents.

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Chapter 3. River sector descriptions

3.1 Summary of sector descriptions The SSSI may be divided into three sectors which are further subdivided into 24 geomorphologically homogenous units based on a range of criteria. The 24 reaches were defined in the previous geomorphological action plan (BBR 2004). Relevant information in that study is reproduced in brief below and has informed this work. The following descriptions cover the three sectors: upper, mid and lower.

The boundaries between these sectors are illustrated in Figures 4, 6 and 8. These were defined by a number of factors, including changes in gradient, planform, cross-sectional profile, major structures, bank material, vegetation cover, channel modification and significant tributaries. The three sectors range from a medium to high gradient river in the upper sector through medium to low gradient in the lower sector.

Blackwater River confluence (right) with the River Axe (left)

This chapter provides a sector summary of the geomorphology, flows and artificial

influences within the three sectors of the Axe SSSI.

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Figure 2 Geomorphological reaches within the SSSI/SAC, as identified in BBR 2004

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3.2 Upper sector

Sector Length Upstream limit and NGR

Downstream limit and NGR

BBR report geomorphological reaches

SSSI unit

Upper 1.5km

NGR ST3247002315 Confluence of Blackwater River

NGR

ST3220401503 Confluence of River Kit

AXE019 - AXE021

1 and 2

Figure 3 Map showing upper sector SSSI units and geomorphological reaches

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3.2.1 Physical character A medium gradient, U-shaped channel form located within a floodplain of 5-10 channel widths on each side. The planform comprises irregular meanders. Channel substrate ranges from silt to coarse gravel with clay also present at the confluence of the Blackwater River. The bed is uniform with few exposed channel deposits with toe accumulations present. Bank sediments range from silt to fine gravel forming cliffed riverbanks with occasional stepped sections along both banks. Flow is varied with runs, riffles and glides all well represented. In-channel vegetation includes submerged, floating emergent, and amphibious macrophyte species together with exposed and submerged tree roots.

3.2.2 Historical change Ordnance Survey maps show the County and Parish boundaries following old river channel meanders. Bend cut-offs have occurred since 1891 in this sector which also displays examples of bend enlargement. These may have been in response to the construction of the London and Southwest Railway which opened its Exeter Extension from Yeovil Junction to Exeter Queen Street in 1860. This runs parallel to the river and crosses it once, between Wadbrook and Axe farms in this sector. The river was straightened and shortened in places to accommodate the railway, causing it to readjust by extending and lengthening meander bends. The 1988 River Habitat Survey (Environment Agency dataset RHS 1988) showed no revetment works within AXE020, which now displays 50% of its banks protected by wood piling as an attempt to protect Wadbrook Farm buildings. This work was carried out in the early 1990s in collaboration with the National Rivers Authority as a trial using green engineering to protect vulnerable locations from bank erosion. This is now a line of willows with the remains of the spiling work still in-channel.

River Axe near the River Kit confluence

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3.2.3 Geomorphological behaviour Sediment is supplied to the channel from a range of sources. Bank erosion occurs extensively throughout the watercourse and includes toe scour, cliff erosion, slumping and slips. Where bank protection has been provided erosion is absent. Point sources such as tributaries, drains and livestock poaching also represent important sources of mostly fine sediment. It appears that much of the coarse sediment in the channel has been transferred from upstream as few sources of coarse sediment are located in this sector. The dominance of fine sediment delivery in this watercourse is a reflection of the composition of floodplain materials. The frequent occurrence of temporary channel deposits reflects relatively active coarse and fine sediment delivery and transfer. The deposition of sediment within the channel encourages bank erosion, resulting in local meander bend growth and cut-offs.

3.2.4 Significant issues Loss of morphological diversity and interruption to natural geomorphological process

due to bank protection.

Interruption of natural geomorphological process due to railway bridges and floodplain

embankments.

Himalayan balsam occurs extensively.

Diseased alders are found throughout the watercourse.

Fine sediment delivery through frequent livestock poaching.

Feature Number

River length 1.49km

River fall 4m

River gradient 1:375

Weirs 0

Artificial fall 0

Road bridges 1

Rail bridges 1

Foot bridges 0

Straightened/reinforced river length

320 m

Table 3 Upper sector summary of features (BBR 2004)

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Figure 4 Upper sector length of each characteristic bank-type (BBR 2004)

Upper Sector

2998

320

0 10135

1035

0

500

1000

1500

2000

2500

3000

3500

BL RI EM PO EC TC

Bank characteristics

Ban

k l

en

gth

in

metr

es

Key:

Bank length

Reinforced bank

Embanked

Poached bank

Eroding cliff

Bank tree cover

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3.3 Mid sector

Sector Length Upstream limit and NGR

Downstream limit and NGR

BBR report geomorphological reaches

SSSI unit

Mid 7.3km

NGR ST3220401503 Confluence of River Kit

NGR SY2878797727 100m u/s of A35 road bridge

AXE022 - AXE031

2

Figure 5 Map showing mid sector SSSI units and geomorphological reaches

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3.3.1 Physical character A low gradient channel located within a symmetric floodplain varying in width from 1-5 channel widths in the upper reaches to >10 channel widths in the lower reaches. The valley forms a concave bowl or terraced valley floor. The channel planform is varied and includes regular meanders (AXE022, 027, 031); irregular meanders (AXE023, 028-030); straight sections (AXE025, 032) and one anastomosed reach (AXE024). Bed material is dominated by gravel/pebble but ranges from silt to cobble. Bank materials vary from silts to cobbles with fines being particularly extensive in the middle reaches. Artificial bank materials are present in reaches AXE025-031. Riverbanks are generally steep or cliffed. Flows include runs, riffles, pools, glides and dead water. Reaches AXE026-027 are exceptions being dominated by slow flows. Both coarse and fine channel deposits occur although coarse are generally more frequent. Channel deposits include mid-channel bars, point bars, side bars and berms, AXE026 has few channel deposits. Submerged channel vegetation increases downstream corresponding with a decrease in riparian tree shading, emergents remain common throughout.

River Axe just downstream of River Kit confluence

3.3.2 Historical change Ordnance Survey maps show the county and parish boundaries following old river channel meanders. Bend cut-offs have occurred since 1891 in this sector which also displays examples of bend enlargement. These may have been in response to the construction of the London and Southwest Railway which opened its Exeter Extension from Yeovil Junction to Exeter Queen Street in 1860. This continues to run parallel to the river and crosses it once in this sector, just downstream of Weycroft Bridge. At Town Weir (AXE029-030), the railway embankment wall forms the left bank of the river, which is geomorphologically constrained here by both the railway and the weir.

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Historic bend cut-offs and bend growth have naturally occurred in reaches AXE023-024, elsewhere change is restricted to localised bend growth. Reaches AXE025-027 and AXE030 have been re-aligned with AXE025-026 also resectioned, all in relation to property protection, the railway line or the alignment of the river to Weycroft Weir. Bank protection consists of walling and blockstone (AXE026-030).

River Axe just north of the A35

3.3.3 Geomorphological behaviour Bank erosion occurs predominantly as toe scour, eroding cliffs and slumps. Generally these supply fine sediments with coarse sediment supply restricted to reaches AXE025 and AXE029. The occurrence of temporary channel deposits reflects relatively active sediment delivery and transfer. The deposition of sediment within the channel encourages bank erosion, which locally has resulted in bend growth and bend cut-off, particularly recently in AXE028-029.

3.3.4 Significant issues Low morphological diversity and interruption to natural geomorphological processes

caused by channel modifications particularly Weycroft and Town Weirs and bank protection measures.

Interruption of natural geomorphological process due to railway embankments and bridges.

Himalayan balsam is present along both banks throughout the reach.

Land management (such as field drains, livestock poaching) impacting on riparian banks, channel and old relic features within the floodplain AXE028-30.

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Feature Number

River length

7.3km

River fall

19m

River gradient

1:380

Weirs

2

Artificial fall

2.9

Road bridges

3

Rail bridges

1

Foot bridges

3

Straightened/reinforced river length

805m

Table 4 Mid sector summary of features (BBR 2004)

Figure 6 Length of each characteristic bank-type (BBR 2004)

Middle Sector

14600

805120 38

5746

4115

0

2000

4000

6000

8000

10000

12000

14000

16000

BL RI EM PO EC TC

Bank characteristics

Ban

k l

en

gth

in

metr

es

Key:

Bank length

Reinforced bank

Embanked

Poached bank

Eroding cliff

Bank tree cover

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3.4 Lower sector

Sector Length Upstream limit and NGR

Downstream limit and NGR

Geomorphological reaches

SSSI unit

Lower

9.8km

NGR SY2878797727 100m u/s of A35 road bridge

NGR SY2594492635 100m u/s of A3052 Axe Bridge

AXE32- AXE42

2 and 3

Figure 7 Map showing lower sector SSSI units and geomorphological reaches

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River Axe downstream of A35

River Axe just downstream of Axe Bridge, showing high tide locking of the river at this point

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3.4.1 Physical character The river displays a low gradient channel within a wide generally symmetric floodplain greater than 10 channel widths. The channel ranges from regular meanders (AXE033, 035, 040, 041), irregular meanders (AXE034, 036, 037) to sinuous (AXE039, 042) and straight sections (AXE 032, 038). Bed sediments range in size from silt to cobbles. Bank materials are similarly variable ranging from clay to pebble. Silt and sand is extensive at the confluence of the River Yarty. Clay is only found in the lower reaches. The channel cross-section is typically U-shaped with steep or vertical banks of 1-2 metres. Only reach AXE032 has a rectangular cross-section. Flow is varied reflecting generally good morphological diversity, which includes runs, riffles, pools, dead water, and glides. Channel deposits vary in frequency; both coarse and fine channel deposits have a high frequency in reaches AXE036, AXE038 and AXE040. Elsewhere, fine deposits occur with moderate frequency while coarse deposits have a low frequency. Channel deposits are predominantly berms, mid-channel bars, point bars and sidebars. Channel vegetation both submerged vegetation and emergent are the dominant types.

3.4.2 Historical change Historical channel migration is evident along this sector particularly around the confluence of the River Yarty (AXE033-034) and Whitford (AXE037-038)). These represent the most geomorphologically active parts of the Axe catchment. Flood embankments have been installed along reach AXE040. Artificial bank materials are present locally in all reaches. Reach AXE032 was resectioned and realigned when the A35 Axminster bypass road was built and check weirs installed to constrain lateral migration of the channel.

1947 air photo showing meander bends lost in building of the A35 bypass with inset map of current alignments

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3.4.3 Geomorphological behaviour Particularly in the upper reaches the low bank cohesion of the natural banks allows lateral channel adjustment. High rates of lateral activity are indicated by the frequency of bank erosion, which includes toe scour, cliffs, slumping, slips and active cut offs. Both fine and coarse material is being supplied to the channel through these diffuse sources. Point sources present also provide additional fine sediment, from localised poaching, field drains and ford crossings. Sediment transport is interrupted by the modifications in flows caused by bridges and weirs, which in turn promotes bend enlargement. In response to these relatively high rates of channel activity bank protection has been provided throughout the watercourse. This varies from localised protection such as blockstone and builders waste to more extensive lengths associated with historic realignments and infrastructure protection for road and rail routes.

3.4.4 Significant issues Lack of morphological diversity in reach AXE032.

Reductions in morphological diversity and interruption to natural geomorphological

processes caused by channel modifications and maintenance activities, particularly

Whitford Weirs, bridge and gauging weir.

Mechanical infilling of old river features within the floodplain.

Himalayan Balsam is present along both banks throughout the reaches.

Diseased alders.

Impact of transport infrastructure on natural river processes.

Feature Number

River length 9.8km

River fall 17m

River gradient 1:576

Weirs 3

Artificial fall 1.4

Road Bridges 2

Rail Bridges 1

Foot Bridges 5

Straightened/reinforced river length 2615m

Table 5 Section summary of features (from BBR 2004)

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Figure 8 Length of each characteristic bank-type (from BBR 2004)

Lower Sector

19600

2615

50 91

5871

1190

0

5000

10000

15000

20000

25000

BL RI EM PO EC TC

Bank characteristics

Ban

k l

en

gth

in

metr

es

Key:

Bank length

Reinforced bank

Embanked

Poached bank

Eroding cliff

Bank tree cover

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Chapter 4. Channel modifications and restoration measures

The original geomorphological assessment of the wider River Axe catchment (BBR 2004) found that broadly the designated reaches of the Axe displayed a morphological diversity within the channel planform and bank structure largely typical of a natural lowland river. However, it identified a number of key issues, including high volumes of sediment reaching the channel, a degraded riparian zone, and priority actions and locations where structures were potentially affecting the designated site, in particular structures such as weirs. The 2011 Axe SSSI Condition Assessment (ECUS, 2011) found selected sections of the Axe SSSI to be in an unfavourable condition in relation to compliance with river profile targets (historic re-sectioning and bank re-enforcement), bank vegetation naturalness, and vegetation community structure and suggested that restoration of a more natural bank profile may help to improve condition in those areas. The more detailed and extensive 2011/12 river SSSI survey again found that broadly the designated reaches of the Axe displayed overall a morphological diversity within the channel planform and bank structure largely typical of a natural lowland river, but that specific structures are having a localised influence on channel functions and form, and that there are riparian vegetation management issues to be addressed.

4.1 Geomorphology and channel change The historic review of the changes in land use and stability of planform of the lower Axe have shown the Axe to be a naturally dynamic river with a mobile planform. The floodplain has been extensively farmed since the Roman period and by the Medieval period is documented as containing areas of strip farming and with meadow management that incorporated seasonal meadow flooding. Over the years riparian structures have been created and many lost by the lateral river migrations across the floodplain and boundaries pragmatically shifted to accommodate this. The channel alignment, recorded on the first field plans in 1776-78, remain evident today often only as isolated features within the floodplain illustrating the dynamic nature of the channel. The observable failure of many recent blockstone revetments introduced to stop bank erosion shows the ongoing difficulty of restraining the natural erosive lateral forces present on the lower Axe. In general, the geomorphological quality of the Axe SSSI is very good. Sediment migration and deposition within the channel is widespread along the River Axe; the presence of coarse sediment has promoted good morphological diversity within the channel, and fine sediments were observed to be within normal levels for the river type. This structural diversity continues to support a range of dependant wildlife species that identified the river as of National and European importance (SSSI and SAC). Channel planform changes and associated bank erosion along the River Axe are an essential part of the natural behaviour of meandering rivers. Localised channel modifications such as weirs, rail and road bridge abutments, embankments, channel re-alignments, bank

This chapter identifies the most significant influences degrading the River Axe

SSSI and proposed potential restoration and management solutions.

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protection and adjoining land management practices, conducted throughout the last 200 years, have interfered with the natural behaviour of the river channel. River condition surveys carried out between 2010-12 showed that seven weirs and 17 bridges were located along the SSSI reach, in some cases impounding flow and interrupting sediment transfer. Bank reinforcement accounted for 10% of the overall bank structure where it inhibited lateral channel migration and sediment availability. Bank vegetation diversity was constrained by farming practices reducing its biodiversity. Colonisation by non-native exotic plant species both within the channel (Canadian water-weed (Elodea canadensis)) and along the banks Himalayan balsam (Impatiens glandulifera) is a threat to native flora and fauna.

4.2 Impact of existing modifications Each identified structure or operation that potentially degrades the ‘favourable condition’ of the river has been evaluated, with the following considered:

Current function

Societal importance and requirement

Geomorphological and ecological impact In-channel structures such as weirs, bridge abutments and sluices can have a fundamental effect on the physical character of a river, altering the amount, location and value of physical habitat provision to support characteristic flora and fauna. Structures can have three main effects:

alterations to the geomorphology and hydraulics of the channel through water impoundment and altering sediment transfer;

alterations to flow regime;

interruption of biological connectivity, including the passage of fish and invertebrates.

Natural England and the Environment Agency recognise the impacts of the many artificial in-channel structures, and the desire, where it is feasible, to remove as many of these structures as possible. The need to do this is heightened by climate change, for which restoring natural river processes, habitats and connectivity are vital adaptation measures. We also recognise that some of these artificial structures may have important functions or historic and cultural associations, which need to be considered carefully with their owners and affected parties when planning and designing river restoration work. Where there is a clear societal need to maintain a structure, the restoration plan should identify it as immovable in the medium term. However, this does not rule out a change to this status should circumstances allow, with some structures becoming removable in future.

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Table 6 Assessment approach

Assessment Comment

Geomorphological and

ecological appraisal

The step identifies physical modifications, management neglect

or practices that are impacting on characteristic river

geomorphology and habitat and, in turn, on favourable condition

status.

Over 13 kilometres of SSSI designated river, associated banks

and riparian zone management and all structures along it have

been screened for this plan.

Societal importance

and requirement

For the issues identified, constraints on restoration action are

then considered. These may include flood risk to property, risk

to critical infrastructure, water supply, food production, and the

historic environment.

After the initial screening assessment the following issues were identified as artificial features or actions or management practices negatively influencing the form and function of the river and in turn the naturalness of the Axe SSSI.

Table 7 Remedial priority issues

Structures/Activities Impacts on SSSI favourable condition

Weirs: Weycroft Weir Town Weir Bow Bridge A35 blockstone weirs Whitford Gauging & blockstone weirs

Alteration to flow regime; modification of channel form e.g. due to upstream deposition and downstream scour on the channel bed; can cause change to aquatic species composition and abundance; change to bank and riparian zone structure. Significant impairment to migration of characteristic species, especially eel and lampreys.

Bridges: Railway bridges Weycroft Bridge Stoney Bridge (& associated flood defence scheme) Whitford Bridge

Alteration to flow regime; modification of channel form e.g. due to upstream deposition and downstream scour on the channel bed; can cause change to aquatic species composition and abundance; change to bank and riparian zone structure.

Bank revetments: examples Wadbrook Farm. Railway Embankments

Direct loss of natural bank habitat and modification of channel form and function

Riparian zone management:

Riparian tree cover Losses due to alder disease, erosion and poor regeneration due to grazing pressure. Associated loss of large woody debris in channel, which would usually create varied physical habitat, and can promote channel recovery where habitat variation is low.

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Himalayan balsam control It out competes native species for space and light reducing natural biodiversity. Potential for bank and soil erosion during winter when balsam dies back.

Canadian pond-weed It out competes native species for space and light reducing natural biodiversity, and increases fine sediment deposition within the channel.

Livestock management Can increase fine sediment deposition within the channel, caused by erosion and bank grazing. This can lead to poor bank habitat structure and diversity.

4.3 Potential restoration and management options Based on the rationale for SSSI river restoration (Natural England 2006) and experience restoring other SSSI rivers, the following types of restoration and management measures apply to the River Axe:

Reduced/modified channel maintenance and other operations, such as fewer removals of gravel shoals and large woody debris, to promote natural recovery of form and function.

Removal/lowering of in-channel control structures, to re-establish riffle and run habitat, restore characteristic water depths, velocities, reduce siltation and allow free movement of sediment and fauna. Refer to Annex 2 for more information on restoration and structures.

Sensitive restoration of banks, using soft engineering including strategic tree planting and, where possible, facilitating dynamic channel processes within the floodplain to restore riparian wetland flora and fauna.

Remeandering or meander reconnection to restore habitat length/area and improve flow, substrate and depth diversity, thereby providing improved habitat conditions for a wide range of characteristic fauna and flora.

Livestock management to stabilise banks and reduce siltation and channel widening. Preferably through reducing stock densities or if not possible through setting back fencing from the channel top to allow some channel movement and occasional grazing/cutting of vegetation as appropriate.

Restoration of lost bankside tree cover to increase structural diversity of the banks and provide shade and complex bank structures within the channel.

Control of invasive exotic plant and animal species to ensure continuity of native plant assemblage and to reduce impacts to river banks and beds, and to maintain the ecological balance of the watercourse.

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Having identified potential key impacts of modifications on the Axe, potentially viable restoration and management options for relevant locations have been identified. The options proposed fall into 4 categories, ranging from ‘do nothing’ to ‘remove or modify structure’, as summarised in Table 8.

Table 8 Summary of potential restoration categories

Option Comment

Assist natural

recovery

This option can lead to restoration over time e.g. where

modification or perturbations are minor and the river environment

can adjust to negate the impact.

Mitigate impact

by modifying

form or

operation

of structure

This option represents a workable alternative where removal is

not viable in the short term and may provide a medium term

solution to restoring favourable condition. This option could

include partial lowering of weirs, alteration of artificial abstractions

or partial removal and green replacement of bank protection,

improvement to migration routes by fish passes or bypass

channels.

Remove

structure/activity

This represents the ultimate long-term goal of restoration.

Constraints may restrict the viability of this option. In such cases,

opportunities for a more environmentally sympathetic structure or

practice should be considered in the longer term.

Other Specific enhancements and management measures can be

adopted to meet the needs of detrimental change and

management activities along the river. These may include

reducing channel and bankside management intensity, tree

planting and weed control.

4.4 Summary of restoration options - assessment sheets

Potential restoration options have been proposed for each location where geomorphological assessment and ecological interpretation has identified a modification as having an impact on the River Axe SSSI. The rationale for the proposed restoration options is summarised for each location. These are found on the management summary sheets listed in Table 9 and presented in Annex 1. These provide the following information:

A high level description of the site/activity;

A photograph of the place or concern;

A summary of key impacts on favourable condition;

Overall benefits of restoration;

Potential restoration options with their pros and cons;

Recommendations for further assessment and next steps. Each potential restoration option will require a combination of interested parties to be involved in their consideration and future progress.

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Table 9 Management sheets Sheet no.

Location NGR Geomorph. reach

Issue

1 Weycroft Weir ST309002 AXE026-027 Weir and bank revetments

2 Town Weir SY296989 AXE029-030 Weir and revetments

3 Bow Bridge A35 blockstone weirs

SY288976 AXE032 Weirs

4 Whitford Bridge SY262953 AXE038 Bridge

5 Whitford gauging weir

SY262953 AXE038 Weir

6 Weycroft Bridge ST307000 AXE027 Bridge

7 Stoney Bridge and Axminster flood defence scheme

SY294987 AXE030 Bridge and floodplain embankments

8 Whitford Bridge blockstone weirs

SY263954 AXE038 Weirs

9 Various

e.g. ST324009 e.g. AXE020 Bank revetments

10 Various AXE030, 040, 041.

Riparian zone - tree cover

11 Throughout All Riparian zone- invasive non-native plants management

12 Throughout All Riparian zone - livestock management

(13*) Railway bridges and embankments

ST324023 to SY266961

AXE019-036 Bank revetments, entrained flow, disconnection of flood flow processes

* NB 13 – a sheet has not been included on this issue, as it is the subject of a funded study. Any plan or project that comes from this will follow formal processes to ensure they are assessed appropriately with regard to the SSSI and SAC.

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Chapter 5. Consultation, actions and implementation

Most land within the Axe catchment is privately owned, so planning, detailed development and implementation of any remedial solution will require involvement, consultation and agreement with relevant landowning individuals, tenants, and organisations, and with appropriate county, district and parish councils, local communities and other interested parties. Restoration actions are suggested in this plan as a means to achieve favourable physical habitat condition of the SSSI and SAC. This plan identifies a suite of potential actions based on a strategic assessment of the river. All the potential actions require further detailed planning and permission from landowners and managers, Natural England and the lead local flood authority and/or the Environment Agency. A Habitats Regulations Assessment will form part of the permitting process.

Working with others Working with natural processes

Working in partnership with landowners and communities throughout the catchment to find and implement ways of delivering the vision Ensuring restoration integrates with other initiatives currently being implemented in the catchment, in particular recognising common objectives and working together to achieve these Accepting that restoration will take many years, but ensuring that actions needed to deliver that long-term goal are implemented in good time

Supporting and continuing positive management in parts of the river that are already in good health Supporting and allowing the river to recover where natural processes are already working well Assisting natural recovery through change in land and river management practices Ensuring the river and catchment is resilient and can adapt to future pressures brought about by climate change Understanding how geomorphology and ecology responds to restoration

Each potential remedial action has been considered in terms of its implications, and a management sheet prepared for wider comment. Find these in Table 9 and Annex 1.

Restoration options have been outlined on the assessment sheets for nine individual physical modifications and three areas where vegetation changes or management practices are degrading the SSSI. The action plan does not identify the detailed cost for each action however; the criteria for establishing priority for individual tasks are set out in Table 10. Support and grant-aid for any work has yet to be clearly identified and will need to be achieved through working in partnership with others over the next few years and is subject to funding being made available.

It is recognised that not all actions can be taken immediately and it is important to prioritise them to make the restoration plan achievable. Whilst some actions will be completed relatively quickly over the next few years, other measures will take more time to develop, assess and be implemented over long timescales.

This chapter identifies the most significant influences degrading the Axe SSSI and

recognises potential remedial solutions

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Table 10 Draft remedial action programme.

Name Reach Potential delivery

mechanisms

Short term (by 2017)

Medium term (by 2020)

Long term (to approx 2050)

Weycroft weirs AXE 026-027 Through Catchment Partnership initiatives

Mitigate Feasibility study and implement preferred option to modify or

remove

Consider sympathetic alternatives when structures reach end of

design life

Town weir AXE 029-030 Through Catchment Partnership initiatives

Immovable - mitigate Consider sympathetic alternatives when structures reach end of

design life

Bow Bridge weirs AXE 032 Through Catchment Partnership initiatives

Mitigate Feasibility study, and implement preferred option to remove or

modify

Monitor outcomes

Whitford gauging weir

AXE 038 Environment Agency

Immovable- mitigate Consider sympathetic alternatives when structures reach end of

design life

Whitford Bridge AXE 038 - Immovable

Whitford blockstone weirs

Axe 032 - Do nothing

Weycroft bridge AXE 027 Highways Authority/

Consenting authorities

Immovable Consider sympathetic alternatives when structures reach end of

design life

Stoney Bridge and Axminster flood defence scheme

AXE 030 Environment Agency/

Highways Authority

Remove shoals as part of maintenance regime if the present a flood risk. Consider least damaging

alternatives to designated site for Axminster flood defence scheme

Consider sympathetic alternatives when bridge structures reach end

of design life

Wadbrook Farm AXE 020 Consenting authorities/ WFD/CES

Watching brief - as structure degrades, replace with sympathetic

alternative

Monitor outcomes

Railway embankments and bridges

In floodplain through all

sections from AXE 019 – AXE 036

Network Rail Consenting authorities/

Watching brief - as structure degrades, replace with sympathetic alternative. Consider remedies to reinstate more natural connectivity

between river and flood plain processes

Monitor outcomes

Riparian tree cover

AXE 030, 040, 041,

Countryside Stewardship

Targeted planting of appropriate tree species, review potential additional

locations

Monitor outcomes

Bank revetment (dispersed)

Numerous (3.7 km)

- Allow to degrade over time, or if genuine need to replace/maintain ensure sympathetic design and implementation

Invasive species All ES/DEFRA Strategic Invasive plant management -starting at upper reaches of river

Monitor outcomes

Appropriate riparian management - livestock

All Countryside Stewardship

/CSF

Sympathetic management of stock access to river

Monitor outcomes

Abbreviations CES Natural England Conservation and Enhancement Scheme CSF Catchment Sensitive Farming (provision of advice) WFD Water Framework Directive

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Figure 9 Remedial actions location plan This map excludes locations that might be identified through more detailed work on the wider ranging issues, or where specific remedial actions may result from modelling studies for EA, Network Rail and Devon County Council.

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Next steps The following next steps are recommended as an immediate outcome of this plan: Comments phase (3 December 2015 – 14 January 2016)

Ask for comments from relevant parties and stakeholders with interests in this plan, including the Catchment Partnership, relevant landowners, and organisations with landowning or other interests in this plan.

Take on board comments where points of factual accuracy or further evidence made.

Log all other detailed comments into additional Annex within the final document, to inform future detailed project planning.

Implementation phase (2016 onwards, funding dependant)

Catchment Partnership to lead on selecting key issues, further exploring options and initiating ways of implement short term actions;

Named organisations to implement short term options.

Catchment Partnership to prioritise next steps for medium and long term sites and identify actions that can start to be progressed alongside short term actions;

Catchment Partnership to maintain a watching brief on sites with long term actions;

Where geomorphology and ecology are good, support ongoing quality;

Environment Agency and Natural England, in collaboration with Catchment Partnership and other stakeholders to revise and update the plan as actions are undertaken or new sites are considered.

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Glossary Chemical status is assessed by compliance with environmental standards for chemicals that are listed in the Environmental Quality Standards Directive (2008/105/EC). These chemicals include priority substances, priority hazardous substances, and eight other pollutants carried over from the Dangerous Substance Daughter Directives. Chemical status is recorded as 'good' or 'fail'. The chemical status classification for the water body is determined by the worst scoring chemical. Ecological status is recorded on the scale of high, good, moderate, poor or bad. 'High' denotes largely undisturbed conditions and the other classes represent increasing deviation from this natural condition, otherwise described as a 'reference condition'. The ecological status classification for the water body, and the confidence in this, is determined from the worst scoring quality element. This means that the condition of a single quality element can cause a water body to fail to reach its WFD classification objectives. Good Ecological Status is defined by the chemical, biological and physical qualities of the river. European Site Conservation Objectives These Conservation Objectives are those referred to in the Conservation of Habitats and Species Regulations 2010 (the ‘Habitats Regulations’) and Article 6(3) of the Habitats Directive. They must be considered when a competent authority is required to make a ‘Habitats Regulations Assessment’, including an Appropriate Assessment, under the relevant parts of this legislation. These Conservation Objectives and the accompanying Supplementary Advice (where this is available) will also provide a framework to inform the measures needed to conserve or restore the European Site and the prevention of deterioration or significant disturbance of its qualifying features as required by the provisions of Article 6(1) and 6(2) of the Directive. These Conservation Objectives are set for each habitat or species of a Special Area of Conservation (SAC). Where the objectives are met, the site will be considered to exhibit a high degree of integrity and to be contributing to achieving Favourable Conservation Status for that species or habitat type at a UK level. Favourable condition If a SSSI site is in favourable condition, it means that the site is being adequately conserved and is meeting its 'conservation objectives'. Favourable condition means that all of the targets for the mandatory attributes (population and habitat) used to assess a feature have been met. Flood Risk Management Plan The European Floods Directive requires flood risk management plans are produced by December 2015. Flood risk management plans highlight the hazards and risks from rivers, the sea, surface water, groundwater and reservoirs and set out how Risk Management Authorities (RMAs) will work together with communities to manage flood risk. Fluvial geomorphology River related landforms and processes Habitats Directive The main aim of the Habitats Directive is to promote the maintenance of biodiversity by requiring Member States to take measures to maintain or restore natural habitats and wild species listed on the Annexes to the Directive at a favourable conservation status, introducing robust protection for those habitats and species of European importance. Council Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora

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Hydromorphology Used to describe the combined processes of hydrology and (geo)morphology that create and sustain the physical structure and habitats in river environments. Macrophyte An aquatic plant that grows in or near water and is emergent, submergent or floating. Riparian Relating to or located on the banks of a river or stream. River Basin Management Plan (RBMP) provides a framework for managing water. They set statutory objectives for river, lake, groundwater, estuarine and coastal water bodies, and summarise the programme of measures to achieve them. They also inform decisions on land-use planning. RBMPs are drawn up for the 10 river basin districts in England and Wales as a requirement of the water framework directive. Unfavourable condition If a SSSI site is in unfavourable condition, it means that the site is not being adequately conserved and not meeting its 'conservation objectives'. Some or all of the targets for the mandatory attributes (population and habitat) used to assess a feature have not been met. Site of Special Scientific Interest (SSSI) conserve and protect the best of our wildlife, geological and physiographical heritage for the benefit of present and future generations. SSSIs give legal protection to the best representative sites for wildlife and geology in England under the Wildlife and Countryside Act 1981

Special Area of Conservation (SAC) are internationally important for their wildlife and home to the rarest and most vulnerable habitats and species in Europe. Special Areas of Conservation (SACs) are strictly protected under the EC Habitats Directive and form part of the European network of protected areas known as Natura 2000. In the UK, these European sites are often also SSSIs or a number of SSSIs joined together.

Site Implementation Plan (SIP) includes the priorities and new measures required to achieve water-dependent Natura 2000 objectives under the Water Framework Directive. The actions in the River Axe SIP for the water dependent habitats inform part of the River Basin Management Plan and its consultation.

Water Framework Directive (WFD) is European Legislation aimed at improving the management of rivers, coasts and estuaries to achieve ‘Good Ecological Status’ or ‘GES’. Good Ecological Status is defined by the chemical, biological and physical qualities of the river.

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Annex 1 Management sheets Sheet no.

Location NGR Geomorp. reach

Issue

1 Weycroft Weir ST309002 AXE026-027

Weir and bank revetments

2 Town Weir SY296989 AXE029-030

Weir and revetments

3 Bow Bridge A35 blockstone weirs

SY288976 AXE032 Weirs

4 Whitford Bridge SY262953 AXE038 Bridge

5 Whitford gauging weir

SY262953 AXE038 Weir

6 Weycroft Bridge ST307000 AXE027 Bridge

7 Stoney Bridge and Axminster flood defence scheme

SY294987 AXE030 Bridge and floodplain embankments

8 Whitford Bridge blockstone weirs

SY263954 AXE038 Weirs

9 Various

e.g. ST324009

e.g. AXE020

Bank revetments

10 Various AXE030, 040, 041.

Riparian zone bank side tree cover

11 Throughout All Riparian zone invasive non-native plants management

12 Throughout All Riparian zone livestock management

PLEASE NOTE: During the comments period, the Management Sheets can be downloaded at http://www.therrc.co.uk/sites/default/files/files/Designated_Rivers/Axe/axe_v1.pdf . They will be incorporated into the final plan.

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Annex 2 Decision making related to structures such as weirs and sluices In-channel structures such as weirs and sluices can have a fundamental effect on the physical character of a river, altering the amount, location and value of physical habitat to support characteristic flora and fauna. Structures can have three main effects:

alterations to the geomorphology and hydraulics of the channel through water impoundment and altering sediment transfer;

alterations to flow regime;

interruption of biological connectivity, including the passage of fish and invertebrates.

Natural England and the Environment Agency recognise the impacts of the many artificial in-channel structures, and the need where it is feasible to remove as many of these structures as possible. The need to do this is heightened by climate change, for which restoring natural river processes, habitats and connectivity are vital adaptation measures. However, we also recognise that some of these artificial structures may have important functions or historic and cultural associations, which need to be considered carefully with their owners and affected parties when planning and designing river restoration work. Where there is a clear societal need to maintain a structure, the restoration plan should identify it as immovable in the medium term. However, this does not rule out a change to this status should circumstances allow, with some structures becoming removable in future. The stages taken in identifying river restoration plan actions for in-channel structures are shown in the Figure X and described below. 1) Assess impact of in-channel structures on habitat and connectivity Whole river restoration planning includes detailed ecological and hydro-geomorphological appraisal of the river. The appraisal must include an assessment of the impact on in-channel structures on the characteristic SSSI river habitat and favourable condition. 2) Evaluation of societal importance (flood risk, heritage etc) Whilst seeking to restore habitat and natural hydro-morphological processes wherever possible, constraints such as flood risk, potential impacts on historic environment, landscape, water supply, flow gauging and the stability of buildings and infrastructure must be recognized and considered. 3) Decision on appropriate action Where structures are impacting on the favourable condition of the river, restoration plans should seek to evaluate whether a structure should be removed, mitigated or deemed to be immovable, taking technical and societal constraints into account. The first option to be considered should be the complete removal of the structure. In the event that the structure cannot be removed due to valid societal constraints, options to mitigate its impact should next be considered. Mitigation options include partial removal, bypassing or lowering, improved weir/sluice management by putting in place an operating protocol, or making the structure as permeable as possible to characteristic biota.

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Fish passes Fish passes only resolve connectivity problems for certain fish species, mainly of commercial importance, e.g. salmon or eels, and do not address the habitat and connectivity needs of the diverse biological community as a whole. The effectiveness of any fish pass can vary depending no design and management. In cases where a structure is judged to be immoveable in the medium term, fish pass improvements may be proposed as a mitigation measure. The longer term restoration plan action should however be to remove or modify the structure. However, where a structure is permanently immoveable, a fish pass may be the only mitigation option. In either case, pass design should consider the needs of the characteristic biological community as a whole, including priority species such as lampreys, bullhead and non-fish species. The potential for a fish pass to be a potential mechanism for further invasive colonisation by non-native invasive species such as American signal crayfish should also be considered.

Figure 10. Decision making process for restoration plan actions related to structures

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Bibliography Babtie Brown & Root, 2004B Catchment Fluvial Geomorphological Audit of the Axe

Catchment. Detailed Geomorphological Survey (Report B) October 2004 Babtie Brown & Root, 2004C Catchment Geomorphological Action Plan: The River Axe

Catchment (Report C) November 2004 Countryside Agency, 1999. Countryside Character. Volume 8: Southwest. ECUS, 2011. Macrophyte surveys of the River Axe SAC. ECUS, 2011. River Axe SSSI Common Standards Monitoring Environment Agency, 1999. Local Environment Agency Plan. Axe and Lim. Environment Agency, 2001. Local Environment Agency Plan. Axe and Lim Action Plan. Environment Agency (2003) River Habitat Survey in Britain and Ireland, Field Survey

Guidance Manual: 2003 Version. Environment Agency, 2003a. River Axe Salmon Action Plan. Environment Agency, 2003b. Devon Catchment Flood Management Plan, Environment Agency, 2004. Otter, Sid, Axe and Lim Catchment Abstraction Man. Strategy. Environment Agency (2010) Position paper on hydromorphological river restoration Environment Agency (2014) South west river basin district Consultation on the draft Flood

Risk Management Plan October 2014 Environment Agency / Diffuse Water Pollution Plan for the Axe Natural England (2014) Gregory, K.J. (ed.) (1997) Fluvial Geomorphology of Great Britain, Geological

Conservation Review Series, No. 13, Chapman and Hall, London

JNCC (2014). Common Standards Monitoring Guidance for Rivers Version

January 2014. Updated from March 2005. Holmes, N., Boon, P. & Rowell, T. (1999) Vegetation Communities of British Rivers: a revised

classification. JNCC, Peterborough. Natural England (2007) Rationale for the physical restoration of the SSSI river series in

England. (Internal paper) Natural England (2009) Conservation objectives and definitions of favourable condition

for designated features of interest (draft) Natural England (2006) Data and analytical requirements of geomorphological

appraisal and associated ecological interpretation for SSSI river restoration.

Natural England (2015) Pollution Risk Assessment and Source Apportionment: River Axe.

Newman, M. (2012) Axe Invasives. Invasive Alien Plan Species Control Programme for Natural England. (Internal paper)

Sear, D.A., Hill, C.T. & Downes R.H.E (2008) Geomorphological assessment of riverine SSSIs for the

strategic planning of physical restoration. Natural England Research Report NERR013

Sweet, R.J. 2004. Computer Modelling of flood flows and floodplain sedimentation. Unpublished. PhD thesis, University of Exeter, 295pp.

STREAM (2010) Planning river restoration advice note

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Available Online Council Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora European Site Conservation Objectives for River Axe Special Area of Conservation: Site code: UK0030248 River Axe SSSI citation http://www.sssi.naturalengland.org.uk/citation/citation_photo/2000139.pdf River Axe SAC citation http://publications.naturalengland.org.uk/file/5728918585737216 River Axe Site Improvement Plan http://publications.naturalengland.org.uk/file/6572555716526080

Natural England latest condition assessment https://designatedsites.naturalengland.org.uk/ReportUnitCondition.aspx?SiteCode=S2000139&ReportTitle=RIVER AXEx?SiteCode=S2000139&ReportTitle=RIVER%20AXE