River Wensum Restoration Strategy Implementation SSSI Unit 47 Common to Mill

FEASIBILITY & ENVIRONMENTAL SCOPING ASSESSMENT

November 2011

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

River Wensum Restoration Strategy

Implementation SSSI Unit 47

Tatterford Common to Fakenham Mill Feasibility & Environmental Scoping Assessment

September 2011 Notice

This report was produced by Atkins for the Environment Agency for the specific purpose of assessing the feasibility of restoring favourable condition to the River Wensum SSSI. This report may not be used by any person other than the Environment Agency without Environment Agency express permission. In any event, Atkins accepts no liability for any costs, liabilities or losses arising as a result of the use of or reliance upon the contents of this report by any person other than the Environment Agency. Document History

JOB NUMBER: 5078052 DOCUMENT REF: 5078052/60/DG/069 Revision Purpose Description Originated Checked Reviewed Authorised Date v.01 Initial Draft Ian Morrissey Kevin Skinner 20/08/2010 Final Draft Final draft for internal review Ian Morrissey Aurelie Paoli Kevin Skinner Don Ross 14/10/2010 Final Final for issue Ian Morrissey Aurelie Paoli Kevin Skinner Don Ross 8/09/2011 Final For publication Ian Morrissey Ellen Derbyshire Kevin Skinner Don Ross 4/11/2011

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Contents Section Page Non Technical Summary 1 1. Introduction 3 1.1 Context 3 1.2 River Wensum Restoration Strategy 7 1.3 Feasibility Assessment aims 9 1.4 Methodology 9 2. Tatterford Common to Fakenham Mill Overview 12 2.1 Terminology and site location 12 2.2 Previous works within Unit 47 15 2.3 RWRS restoration vision for Unit 47 15 3. Environmental Baseline 17 3.1 Introduction 17 3.2 Common environment features across all reaches 18 3.3 Environmental baseline for each reach within Unit 47 31 4. Consultation 61 4.1 Introduction 61 4.2 Consultation with key stakeholders 61 4.3 Drop-in session September 2009 63 4.4 Future consultation 63 5. Multi-Criteria Analysis Options Appraisal 65 5.1 Introduction 65 5.2 Constructing the MCA tool 65 5.3 Using the MCA tool 71 6. Developing Conceptual Design 83 6.1 Introduction and approach 83 6.2 Description of River Restoration and Targeted Maintenance options 83 6.3 Reach 26: Fakenham Reach 91 6.4 Reach 27: Reach 95 6.5 Reach 28: Moor Reach 99 6.6 Reach 29: Shereford Reach 105 6.7 Reach 30: South Mill Reach 110 6.8 Reach 31: Confluence Reach 114 7. Cost Estimate 118 7.1 Previous cost estimates 118 7.2 Present cost estimates 119 7.3 Potential cost savings 120 7.4 Delivery 123 7.5 Summary 125 8. Scoping 128 8.1 Introduction 128 8.2 Method of assessment 130 8.3 Results of scoping 131 Unit 47 Tatterford Common to Fakenham Mill_Final.docx

River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

9. Consents 139 10. Project Risks 141 11. Conclusions and Recommendations 143 11.1 Conclusions 143 11.2 Recommendations 144 12. References 145 Appendices 147 Appendix A – Multi-Criteria Analysis technical note Appendix B – Costings Appendix C – Ecology tables Appendix D – Terrestrial SSSI unit links to River Wensum SSSI units List of Figures Figure 1.1- Unit 47 River Wensum location plan 4 Figure 1.2 – Environmental and restoration related investigations and events, showing how this assessment fits within the process of realising restoration on the River Wensum 6 Figure 1.3 - The approach adopted during feasibility assessment for determining the recommended restoration option on individual reaches and the overall river unit 10 Figure 2.1 - Location of Reaches 26 to 31 within Unit 47 14 Figure 3.1 - Environmental constraints on Unit 47 27 Figure 3.2 - Environmental baseline for Reach 26 (Fakenham Reach) 34 Figure 3.3 - Environmental baseline for Reach 27 (Hempton Reach) 38 Figure 3.4 - Environmental baseline for Reach 28 (Moor Reach) 42 Figure 3.5 - Environmental baseline for Reach 29 (Shereford Reach) 46 Figure 3.6 - Environmental baseline for Reach 30 (South Mill Reach) 49 Figure 3.7 - Environmental baseline for Reach 31 (Confluence Reach) 52 Figure 6.1 - Conceptual restoration plan for Reach 26 (Fakenham Reach) 94 Figure 6.2 - Conceptual restoration plan for Reach 27 (Hempton Reach) 98 Figure 6.3 - Conceptual restoration plan for Reach 28 (Moor Reach) 104 Figure 6.4 - Conceptual restoration plan for Reach 29 (Shereford Reach) 109 Figure 6.5 - Conceptual restoration plan for Reach 30 (South Mill Reach) 113 Figure 6.6 - Conceptual restoration plan for Reach 31 (Confluence Reach) 117 Figure 8.1 - Environmental Scoping within the EIA process 129

List of Tables Table 1.1 - Chapters constituting this report 7 Table 2.1- Summary of previous restoration works consented on Unit 47 (JBA, 2007) 15 Table 2.2 - Recommended restoration measures for each reach in Unit 47 as provided in the RWRS (JBA, 2007) 16 Table 3.1 - Mill details in Unit 47 (Environment Agency, 2007) 24 Table 3.2 - Water quality (Environment Agency, 2010) 25 Table 3.3 - Condition summary of Unit 47 attributes (Natural , 2010) 26 Table 3.4 - Baseline information common to Unit 47 28 Table 3.5 - Baseline information specific to Reach 26 (Fakenham Reach) 31 Table 3.6 - Baseline information specific to Reach 27 (Hempton Reach) 35 Table 3.7 - Baseline information specific to Reach 28 (Moor Reach) 39 Table 3.8 - Baseline information specific to Reach 29 (Shereford Reach) 43 Unit 47 Tatterford Common to Fakenham Mill_Final.docx

River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Table 3.9 - Baseline information specific to Reach 30 (South Mill Reach) 47 Table 3.10 - Baseline information specific to Reach 31 (Confluence Reach) 50 Table 4.1 - Consultation undertaken to date (August 2010) 61 Table 5.1 - Overview of the process by which the MCA was constructed and applied 65 Table 5.2 - Restoration measures recommended in previous studies 66 Table 5.3 - Options identified for restoration on the River Wensum 67 Table 5.4 - Description of river restoration measures as defined under option G5 68 Table 5.5 - Criteria defined for the MCA 70 Table 5.6 - Scoring system defined for the Multi-Criteria Analysis 71 Table 5.7 - Results of MCA for Reach 26 (Fakenham Reach) 73 Table 5.8 - Results of MCA for Reach 27 (Hempton Reach) 74 Table 5.9 - Results of MCA for Reach 28 (Moor Reach) 75 Table 5.10 - Results of MCA for Reach 29 (Shereford Reach) 76 Table 5.11 - Results of MCA for Reach 30 (South Mill Reach) 77 Table 5.12 - Results of MCA for Reach 31 (Confluence Reach) 78 Table 5.13 - Summary of favourable options and measures for Unit 47 81 Table 6.1 - Different management classes of restoration activity 84 Table 6.2 - Active and passive river restoration measures 84 Table 6.3 - River restoration measures and their potential ecological benefits 87 Table 6.4 - The effect of river restoration measures according to flow condition 89 Table 6.5 - Significant features and possible measures observed for Reach 26 during site visit 91 Table 6.6 - Review of strategy objectives and recommendations for Reach 26 92 Table 6.7 - Recommended restoration options for Reach 26 93 Table 6.8 - Significant features and possible measures observed for Reach 27 during site visit 95 Table 6.9 - Review of strategy objectives and recommendations for Reach 27 96 Table 6.10 - Recommended restoration options for Reach 27 97 Table 6.11 - Significant features and possible measures observed for Reach 28 during site visit 99 Table 6.12 - Review of strategy objectives and recommendations for Reach 28 101 Table 6.13 - Recommended restoration options for Reach 28 102 Table 6.14 - Significant features and possible measures observed for Reach 29 during site visit 105 Table 6.15 - Review of strategy objectives and recommendations for Reach 29 106 Table 6.16 - Recommended restoration options for Reach 29 107 Table 6.17 - Significant features and possible measures observed for Reach 30 during site visit 110 Table 6.18 - Review of strategy objectives and recommendations 111 Table 6.19 - Recommended restoration options for Reach 30 112 Table 6.20 - Significant features and possible measures observed for Reach 31 during site visit 114 Table 6.21 - Review of strategy objectives and recommendations 115 Table 6.22 - Recommended restoration options for Reach 31 115 Table 7.1 - RWRS Unit 47 cost estimate (JBA, 2007) 118 Table 7.2 - Halcrow PSA Unit 47 cost estimate 119 Table 7.3 - Comparison of cost estimates between JBA and Halcrow reports for Unit 47 119 Table 7.4 - Unit 47 cost estimates for various river restoration measures 120 Table 7.5 – Unit 47 cost estimates for each reach and restoration measure 120 Table 7.6 - Options that typically generate or require spoil 121 Table 7.7 - Gravel substitution using surplus fill 122 Table 7.8 – Revised costs for gravel glides with length substitution 123 Table 7.9 - Recommended phasing of work 124 Table 7.10 Recommended phasing of restoration measures for Unit 47 125 Table 7.11 - Comparison of costs between 2007 and 2010 studies 127

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Table 8.1 - Classifying and evaluating the significance of potential environmental effects in the scoping process (adopted from European Commission, 2001) 130 Table 8.2- Environmental scoping assessment for recommended restoration options 133 Table 8.3 - Issues scoped into the EIA process 137 Table 8.4 - Issues scoped out of the EIA process 138 Table 9.1 - Likely planning consents and permissions 139 Table 10.1 – Key project risks that may delay the delivery of the recommended options for Unit 47 142

List of Plates Plate 1 – Water level control structures upstream of Fakenham Mill 22 Plate 2 – Fixed weir structure at Sculthorpe Mill (with boards removed) 23 Plate 3 – Downstream view from road bridge at site of South Mill 23 Plate 4 – Reach 26: Fakenham Mill automated sluice and gauge 53 Plate 5 – Reach 26: River Wensum on approach to Fakenham Mill. Emergent vegetation (right bank) was installed as river edge enhancement in 2001 (NGR TF91792 29296, August 2010) 53 Plate 6 - Reach 26: Upstream of Fakenham Mill with over-wide and deep river section (Hempton Road to the right) 54 Plate 7 – Reach 27: River Wensum looking downstream from the A 1065 road bridge (NGR TF91293 29667, August 2010) 54 Plate 8 - Reach 27: River Wensum looking towards Hempton meander loop which was reconnected in 2003 (NGR TF90964 29611) 55 Plate 9 - Reach 27 – Installed gravel glide with aquatic plant assemblage 55 Plate 10 - Reach 27: River Wensum upstream of reconnected meander loop (looking u/s) showing natural vegetation and berm encroachment 56 Plate 11 – Reach 27: River Wensum flowing confined within high embanked section. Embankments contain high proportion of gravels indicating spoil generated from historic instream dredging (NGR TF90347 29721, August 2010) 56 Plate 12 – Reach 28: River Wensum exhibiting good gravel habitat at site of self-sown willow (NGR TF89653 30316, August 2010) 57 Plate 13 -– Reach 28: Location of possible channel realignment to TLHB at Sculthorpe Moor (NGR TF89687 30001, August 2010) 57 Plate 14 – Reach 29: River Wensum at old railway crossing, Shereford. River flow negligible, channel significantly over widened with silt bed and abundant instream plant growth (NGR TF88622 29631, August 2010) 58 Plate 15 – Reach 29: River Wensum downstream of Southmill Farm. Channel is self narrowing through vegetated berm encroachment, free flowing with water starwort and clean gravel. (NGR TF88110 28804, August 2010) 58 Plate 16 – Reach 30: River Wensum looking downstream on approach to South Mill. Over wide and deep with marginal plant encroachment and silty bed (NGR TF88080 28223, August 2010) 59 Plate 17 – Reach 30: River Wensum channel choked with emergent bur reed causing an obstruction to flow (NRG TF87762 28053, August 2010) 59 Plate 18 – Reach 31: at confluence with the River Wensum (NGR TF87573 28036, August 2010)60 Plate 19 – Reach 31: River Tat at confluence with the River Wensum (NGR TF87573 28036, August 2010)60 Plate 20 – River channel projects differ from full restoration to erosion control measures 83

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Abbreviations Acronym Meaning

ASPT Average Score Per Taxon

AOD Above Ordnance Datum

BAP Biodiversity Action Plan

CWD Coarse Woody Debris (term used in RWRS for LWD)

EIA Environmental Impact Assessment

ECSFDI England Catchment Sensitive Farming Delivery Initiative

ESA Environmentally Sensitive Area

GIS Geographic Information System

GPDO General Permitted Development Order

IDB Internal Drainage Board

JNCC Joint Nature Conservation Committee

KLWNDC King’s Lynn and West District Council

LWD Large Woody Debris

MCA Multi-Criteria Analysis

NCC Norfolk County Council

NNDC District Council

NTAXA Number of Taxa

PSA Public Service Agreement

RBMP River Basin Management Plan

RCS River Corridor Survey

RoC Review of Consents

RHS River Habitat Survey

RRC River Restoration Centre

RWRS River Wensum Restoration Strategy

SAC Special Area of Conservation

SI Statutory Instrument

SSSI Site of Special Scientific Interest

TLHB True Left Hand Bank

TRHB True Right Hand Bank

TWS Total Weighted Score

WFD Water Framework Directive

WLMP Water Level Management Plan

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Non Technical Summary

Introduction This feasibility and environmental scoping report identifies river restoration options that could be implemented to restore Unit 47 (Tatterford Common to Fakenham Mill) of the River Wensum Site of Special Scientific Interest (SSSI) to ‘unfavourable recovering’ or ‘favourable’ ecological condition. To achieve this aim, a range of specific technical, economic, environmental and social objectives need to be met. Objective The primary objective is to identify a range of restoration options to deliver physical modifications that will improve the ecological condition of the River Wensum. If river alterations are not implemented there remains a risk that the Government Public Service Agreement (PSA) target for SSSI condition will not be met and the river will not be returned from its current ‘unfavourable no change status’ to ‘unfavourable recovering’ or ‘favourable’ ecological condition. This report leads on from the River Wensum Restoration Strategy by assessing all river management options including river restoration in a transparent manner to demonstrate to stakeholders that all options for improving the SSSI condition of the River Wensum were considered. A key outcome of this report is the development of a conceptual design for the recommended restoration option. The River Wensum is also designated as a “Protected Area” under the European Union Water Framework Directive. An objective of the Anglian River Basin Management Plan is to improve the river from its current bad ecological potential to good ecological potential by 2027. Measures to meet this objective include large scale habitat improvements, such as removing impoundments on the river, restoring gravel beds, narrowing the channel, increasing the amount of large woody material and modifying the weed cutting regime at critical phases of fish life cycles.

Consultation Consultation was in the form of a public drop in day at Fakenham Race Course (September 2009) with submission of feedback forms from the public. The Environment Agency communicated with riparian landowners, and organisations including Natural England, Norfolk County Council, North Norfolk District Council, Fakenham Town Council, the Norfolk Rivers Internal Drainage Board, Norfolk Wildlife Trust and water recreation groups including anglers and canoeists. Initial input from these organisations suggests strong support for implementing restoration options and other wider environmental enhancements. However a minority remain convinced that more regular maintenance, including dredging, as well as the retention of the impoundments behind mills, is the key to improving river health.

Options for restoration A Multi-Criteria Analysis (MCA) was applied across a range of strategic river management / restoration options. The MCA allowed the appraisal of all options individually, and against each other, for their technical, economic and environmental constraints and opportunities. This provided an objective and transparent method for determining the most suitable restoration option for improving the SSSI condition. The result of the MCA for this river unit showed that our recommended option is likely to be a combination of river restoration works and targeted maintenance. This may also involve changing the retained water level at Fakenham Mill and re-evaluating the current maintenance regime.

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

A conceptual design for river restoration and targeted maintenance has been developed and this can be applied across the entire unit, at a reach level or at a more discrete ‘section’ level. Costs Indicative costs for implementing the preferred river restoration option have been developed based on a per unit length of the main river channel. The estimated cost of the recommended options for this unit is £403,000 (to the nearest thousand). Cost savings have been explored through the re-use of previously excavated spoil to raise the river bed, reducing the extent of certain measures without compromising their function, using locally sourced materials and phasing the work efficiently.

Environmental Scoping A high level environmental scoping appraisal has been undertaken against the potential restoration options. The result of this assessment has enabled environmental criteria to be scoped in or out of the Environmental Impact Assessment (EIA) process. In addition, key environmental constraints and opportunities have been identified that will require supplementary appraisal during detailed design of restoration projects.

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1. Introduction 1.1 Context

1.1.1 River Wensum The River Wensum is a low gradient chalk river located in Norfolk, England (see Figure 1.1). The river, and a number of adjacent floodplain land parcels, are of national and international importance for wildlife, being designated as a Site of Special Scientific Interest (SSSI) and as a Special Area of Conservation (SAC). As a chalk river the Wensum is also recognised as a priority habitat within the UK Biodiversity Action Plan (BAP). Past physical modifications to the River Wensum and tributaries have been undertaken to drain adjacent lands to improve their agricultural value, and to provide water storage for milling. These modifications have included extensive dredging which has straightened and over-deepened the channel, significantly impacting on the natural geomorphology and ecology of the river. The 14 redundant mill structures along the course of the River Wensum have significant hydrological impounding effects, with river water backing up behind these structures under a range of flows. This results in sluggish flows and accumulation of sediment in the channel, which, over time, have also contributed to the River Wensum being in unfavourable condition. The latest condition assessment of the SSSI (Natural England, 2010) found all of the riverine SSSI units to be in ‘unfavourable no change’ condition. Reasons cited for this condition include poor water quality, excessive siltation and physical modifications. Physical modifications of the river, and to some extent siltation, will be addressed through a programme of river restoration measures designed to help return the river to ‘unfavourable recovering’ or ‘favourable’ ecological condition. This Feasibility Report considers various options and measures by which this restoration can be achieved. Issues of poor water quality are being addressed at a strategic level through other projects such as the England Catchment Sensitive Farming Delivery Initiative (ECSFDI) and a review of existing abstraction licences and discharge consents. The Anglian River Basin Management Plan (RBMP) produced by the Environment Agency as required under the EU Water Framework Directive (200/60/EC) identifies the River Wensum upstream of Norwich as a heavily modified water body with bad ecological potential. The river’s bad ecological potential is attributed to a failure in the ecological status of diatoms (microscopic algae). However, its hydromorphological limitations, resulting from historic alterations and unsympathetic management, will also need to be addressed if the river is to achieve good ecological potential. The River Basin Management Plan includes a programme of measures, including river restoration, to improve the ecological condition of the river.

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River Wensum Restoration Strategy Implementation SSSI Unit 46: Feasibility and Environmental Scoping Report

Figure 1.1- Unit 47 River Wensum location plan

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

1.1.2 Feasibility Report This report continues the work commenced through the River Wensum Restoration Strategy (RWRS) (JBA, 2007), and represents the next step in the implementation of restoration. It defines a preferred restoration approach for Unit 47 (Tatterford Common to Fakenham Mill). The outcomes of this feasibility report will inform the detailed design and implementation of river restoration for this section of channel. The feasibility assessment continues the partnership between the Environment Agency and Natural England (formerly English Nature). It relates specifically to Unit 47 (River Wensum, Tatterford Common to Fakenham Mill) and the six ‘reaches’, 26 to 31, which fall within this unit (see Section 2.1 for definitions of the terms ‘reach’ and ‘unit’). Figure 1.2 illustrates where this feasibility assessment fits within the planning of restoration on the River Wensum. Fakenham Mill marks the downstream limit of Unit 47 with the upstream limit approximately 300m above the confluence with the River Tat (Unit 46). Feasibility reports are available as separate documents for the following river SSSI units:  Unit 46 River Tat  Unit 48 Fakenham Mill to Great Mill  Unit 49 Great Ryburgh Mill to Bintree Mill  Unit 50 Bintree Mill to Mill  Unit 51 North Elmham Mill to Mill  Unit 52 Elsing Mill to Mill  Unit 53 Lenwade Mill to Mill  Unit 54 Taverham Mill to Mill.

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

An ecological survey (Holmes, 1980) of the river established that plant communities present in 1980 Ecological survey the upper reaches were typical of chalk rivers. This survey was repeated in 2002 (CAPM, 2002).

The Wensum Valley Countryside Management Project was established in 1988 as a joint venture between the Countryside Commission and local authorities. The objectives of the 1988 Wensum Valley Countryside Management Project project included the enhancement of wildlife habitats, landscape and recreational value of the valley.

The entire river was notified as a SSSI in February 1993, as an example of an enriched 1993 SSSI designation calcareous lowland river. The citation describes it as “probably the best whole river of its type in nature conservation terms” (English Nature, 1993).

The Wensum Valley Strategy was published in 1994 by the Wensum Valley Project to provide Wensum Valley Strategy 1994 a framework for taking the project objectives forward and defines policies for future management of the valley.

The River Rehabilitation Feasibility Study of the River Wensum by Econ represented the first River Rehab WLMP 1999 specific review of restoration options for the River Wensum. In 1999, the first Water Level Feas Study Management Plan for the Wensum was also produced (Environment Agency, 1999).

The Wensum Valley Project hosted a meeting between the Environment Agency, English 2002 Wensum Forum Nature and local landowners / IDB members.

A condition assessment of the SSSI unit was undertaken by English Nature (now Natural SSSI Condition Assessment 2002 England) and concluded that the river was in ‘unfavourable declining’ condition due mainly to

water impoundment caused by physical structures (e.g. mills), siltation and water quality.

2004 - Geomorphological appraisal of the Geodata Services assessed the form and function of the river, and provided reach-based

2005 River Wensum SAC guidance on the management required to restore the natural geomorphology (Sear et al., 2006)

Wensum Fisheries Action Plan The Wensum Fisheries Action Plan group identified the need to fund and implement further 2004 habitat restoration schemes on the river to aid the sustainable recovery of fish stocks

This steering group was convened in order to consider the outcomes of the geomorphological English Nature Steering Group 2005 appraisal and to determine a way forward for improving the condition of the SSSI through river convened restoration.

Qualifying features for the SAC designation are white-clawed crayfish, Desmoulin’s whorl snail, 2005 SAC designation confirmed brook lamprey, bullhead and water crowfoot vegetation communities This revision of the previous Water Level Management Plan (1999) provides a framework for Water Level Management Plan, managing appropriate water levels, and was driven largely by the need to achieve nature 2007 River Wensum SSSI conservation objectives. Recommendations related to promoting agri-environment schemes and modifying impounding mill structures.

The River Wensum Restoration Strategy (RWRS) was completed by JBA in November 2007 River Wensum Restoration for Natural England, and represents a culmination of much of the previous work. This strategy 2007 Strategy considered the entire River Wensum but identified a range of high level river restoration options on a reach-by-reach basis.

Condition assessment of the SSSI unit was undertaken by Natural England and concluded that the river was in ‘unfavourable no change’ condition. Reasons cited for the condition include 2010 SSSI Condition Assessment water abstraction, water pollution from agriculture / run off and discharges, inappropriate water levels and inappropriate weirs, dams and other structures.

Feasibility Report: Unit 47 - This report considers a number of restoration options specifically for Unit 47 and recommends the preferred restoration measure, or suite of measures, for each reach within the unit. The Tatterford Common to Fakenham report makes recommendations as to which of these measures should be progressed to 2010

Present Mill achieve improvement for the unit as a whole. Future Outline and Detailed design of The detailed design of the recommended measures will be undertaken and associated consent applications (e.g. Flood Defence Consent) will be made. recommended options for the unit An environmental assessment of the proposed scheme will be undertaken

Future Construction River restoration measures will be constructed. Future Monitoring Monitoring of the effectiveness of the constructed measures will be on-going.

Figure 1.2 – Environmental and restoration related investigations and events, showing how this assessment fits within the process of realising restoration on the River Wensum

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1.1.3 Structure of this Report This report has been structured to reflect the sequential process by which the recommended restoration options have been determined. Table 1.1 lists the report chapters and provides a brief description of their contents. Table 1.1 - Chapters constituting this report

Chapter Title Description This chapter presents the context of the River Wensum, and 1 Introduction introduces the RWRS. It also discusses the methodology used in this report. Chapter 2 introduces the specific section of river considered in this Tatterford Common to report, namely Unit 47, discussing location, previous restoration 2 Fakenham Mill initiatives, and those restoration measures recommended by the Overview RWRS. Chapter 3 provides an overview of the environmental baseline for 3 Environmental Baseline the unit. It is provided on a reach by reach basis, focusing on reach- specific information. Chapter 4 provides details of the consultation process undertaken 4 Consultation as part of this feasibility assessment, and the main issues raised. Chapter 5 presents the Multi-Criteria Analysis explaining the 5 Options Appraisal methodology and those options which scored highest for each reach. Chapter 6 presents a conceptual design for the recommended Developing Conceptual 6 restoration measures for each reach based on results from the Multi- Design Criteria Analysis. Chapter 7 provides an estimate of costs for the preferred restoration 7 Cost Estimates option and identifies potential cost saving efficiencies in materials and phasing of the proposed works. The specific restoration plan proposed for the unit is subjected to an environmental scoping process. This determines the key 8 Environmental Scoping environmental issues to be considered in the environmental assessment. Chapter 9 discusses the consents that would be required prior to 9 Consents construction of the restoration works. This chapter tables the key project risks associated with the 10 Project Risks planning and implementation of the project. Conclusions and Chapter 11 concludes the report with recommendations for taking 11 Recommendations the project forward.

1.2 River Wensum Restoration Strategy The project was initiated in response to a number of key drivers. The most significant of these are listed below.  The Government’s Public Service Agreement (PSA) target for SSSIs constitutes the main driver for physical restoration of the river, and hence the main driver behind the RWRS. River restoration on the Wensum will contribute to the national target of 95% (by area) of SSSIs being in ‘favourable’ or ‘unfavourable recovering’ condition by 31 December 2010. All riverine units within the Wensum SSSI are currently in ‘unfavourable declining’ condition.  As a European Natura 2000 site, measures are required to ensure that the River Wensum moves towards ‘favourable’ conservation status. The European features of the site are; bullhead, brook lamprey, Desmoulin’s whorl snail, white-clawed crayfish and water crowfoot plant communities.  The River Basin Management Plan (RBMP) prepared for the Anglian River Basin District as required by the Water Framework Directive identifies the River Wensum upstream of Norwich as a heavily modified water body currently with Bad overall Potential. The RBMP sets objectives for the water body to reach Good Ecological Potential by 2027 and Good Chemical Status by 2015 and the RWRS is cited as a key action necessary to deliver these objectives. Measures include large scale habitat improvements to address those factors limiting natural Unit 47 Tatterford Common to Fakenham Mill_Final.docx 7

River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

hydromorphological functioning of the river and to restore favourable conditions for a range of fish species. Proposed actions cited by the RBMP for the River Wensum protected area include reducing impoundments on the river, restoring the gravel beds, narrowing the channel, increasing the amount of in-stream woody material and modifying the weed cutting regime at critical phases of fish life cycles.  Chalk rivers are a priority BAP habitat, with England supporting 85% of the world resource. The Environment Agency is the lead authority for this habitat, and objectives are defined in the Chalk River Habitat Action Plan produced jointly by the Environment Agency and Natural England. The Action Plan recognises the quality and importance of chalk rivers ecologically, hydrologically, recreationally and culturally (Environment Agency / Natural England, 2004).  River restoration will also contribute to the objectives of the River Wensum Fisheries Action Plan, River Wensum Water Level Management Plan (Environment Agency, 2007) and Rivers Catchment Flood Management Plan. 1.2.1 Approach The RWRS report provided comprehensive high level guidance for restoration of the River Wensum. The chief aim of the strategy was to provide a whole river vision for implementation of restoration by developing restoration delivery plans on a reach-by-reach basis throughout the SSSI. The undertaking of the RWRS involved, amongst others, the following key activities:  Reviewing of existing baseline information.  Consulting with steering group members, including the River Restoration Centre (RRC), as well as with key local stakeholders.  Reviewing the river reaches and restoration measures proposed in the Geomorphological Appraisal.  Mapping current conditions on the River Wensum and comparing them to expected semi- natural conditions in Norfolk.  Determining a cost-band for each of the RWRS reaches. The above culminated in the production of a technical report (JBA, 2007). 1.2.2 Outputs The RWRS identified and recommended a number of restoration and management measures including: 1. Implement structural modification to lower, remove or bypass water control structures at mills.

2. Raise bed levels and restore the gravel bed substrate where appropriate.

3. Narrow over-widened sections of river.

4. Introduction / retention of woody debris.

5. Reconnection of 8km of channel to its original channel.

6. Reconnection of the river to its floodplain through removal of embankments where appropriate.

7. Creation of berms to stabilise silt / control silt deposition in the channel.

The strategy culminates in a suite of high level recommendations presented for each of the reaches in Unit 47. This provides a framework for delivering restoration and a starting point for the implementation of restoration on a reach by reach basis.

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

1.3 Feasibility Assessment aims The overall aim of this feasibility assessment, and hence this report, is to progress the implementation phase of restoration and deliver the measures required for the river to meet its objectives under the Water Framework Directive and to meet the PSA targets for the River Wensum SSSI. The key objectives of this feasibility assessment are to:  Determine the most suitable restoration measure, or suite of measures, for Reaches 26 to 31.  To consult with local landowners and stakeholders on the opportunities and constraints for restoration on a reach by reach basis.  To subsequently recommend an overarching restoration and river management conceptual design for Unit 47.  To provide a detailed cost estimate of implementing the conceptual design.  Undertake an environmental scoping assessment of the recommended restoration options. In restoring the hydrological linkage between the river and its floodplain, there should also be consideration of the hydrological linkage between the river SSSI unit, and adjacent terrestrial SSSI units. There are seven terrestrial SSSI units adjacent to Unit 47 of the River Wensum SSSI. This feasibility assessment builds on the RWRS by considering the measures recommended in the strategy, as well as new options for river restoration and river management. A process of Multi-Criteria Analysis (MCA) has been used to determine the most suitable restoration measures or suite of measures for each reach. Section 1.4 provides further detail regarding the adopted methodology. 1.4 Methodology This feasibility assessment involved undertaking the following key activities listed in chronological order. These are described in detail in Sections 1.4.1 to 1.4.7, and Figure 1.3 illustrates the process. 1.4.1 The establishment of detailed baseline conditions for a specific reach. A large amount of baseline data exists for the River Wensum. Numerous reports and raw data were reviewed as part of this feasibility assessment. The majority of this information relates to the River Wensum as a whole, and detailed reach-specific data is less readily available. Section 3.1 sets out more information. In addition, a number of site visits were undertaken throughout the unit by different members of the project team to confirm the desk-top research. Specific baseline conditions for each reach were mapped on an environmental constraints plan.

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Unit 47: Tatterford Common to Fakenham Mill Reach 26 Reach 27 Reach 28 Reach 29 Reach 30 Reach 31 Fakenham Reach Hempton Reach Moor Reach Shereford Reach South Mill Reach Confluence Reach Establish baseline for each of the reaches individually

MULTI CRITERIA ANALYSIS

Construction of MCA tool: identification of options, and defining the criteria by which they will be evaluated.

Application of MCA tool (Ecology, Project Delivery and Technical aspects considered) for each reach

RIVER RESTORATION OUTLINE SCOPING

MCA identification of preferred (highest scoring) options for each reach

Recommended option and measures for each reach

Recommended options and measures for each of the reaches are considered relative to one another and a cost estimate calculated per measure for the unit as a whole. The cost estimate is further refined by considering how cost savings could be made by using alternative construction materials and phasing the works to reduce double handling

ENVIRONMENTAL SCOPING

Environmental scoping of recommended option for this unit

Consents and permissions identified for the scheme to progress to detailed design and construction

Identification of project risks in progressing conceptual design to detailed design

Conclusion and recommendations

Figure 1.3 - The approach adopted during feasibility assessment for determining the recommended restoration option on individual reaches and the overall river unit

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

1.4.2 The identification of a full suite of possible restoration measures, including those recommended in the RWRS A generic list of all management and restoration options possibly applicable to the River Wensum was generated through reviewing key documents such as the RWRS (JBA, 2007) and geomorphological appraisal (Sear et al., 2006), and through public consultation at the drop-in sessions undertaken by the Environment Agency, Natural England and Atkins in late 2008 and early 2009 on units 46, 48, 50, 52 and 53 and September 2009 for Unit 47. From the above activities, six main option groups were identified, and were taken forward for consideration using the Multi-Criteria Analysis (MCA) tool. These options are discussed further in Chapter 5, with further detail given in Appendix A. 1.4.3 The evaluation of restoration, maintenance and alternative options by means of Multi-Criteria Analysis Once identified, the six main option groups were evaluated for each reach using a MCA tool. This was considered necessary to ensure that a transparent, defendable and replicable technique of selecting options could be consistently applied. The MCA technique scores the listed options (and the different measures within the river restoration and alternative options) in terms of the degree to which they meet certain criteria, which are broadly grouped under the headings of ‘Ecological’, ‘Project Delivery’ and ‘Technical’. The highest scoring options / measures were considered to be the ‘preferred suite of options’ for that specific reach and were taken forward for consideration in terms of cost. The MCA technique was carried out on a reach-by-reach basis. 1.4.4 The development of a conceptual design based on the recommended options and suite of measures for each of the reaches considered The recommended options / measures for each reach were considered and professional judgement was applied to determine the appropriate combination of the reach-specific solutions to realise improved conditions for the SSSI unit as a whole. A conceptual design was developed for each reach and these are displayed on base maps in Chapter 6. 1.4.5 The consideration of costs associated with these options and specific river restoration measures A detailed cost estimate was calculated and this was based on a cost per unit length for the different measures and applied to a conceptual design for each reach. Cost savings from phasing work appropriately and using local materials were explored. Chapter 7 describes this in further detail. 1.4.6 Environmental scoping of the recommended option for the unit The recommended option (conceptual design) was subjected to an environmental scoping exercise, so as to determine the significant environmental issues which would warrant a detailed assessment at the next stage of the process. This includes an Environmental Report to be drafted in parallel with the detailed design. The details of this scoping exercise are provided in Chapter 8. 1.4.7 Identification of potential project risks, permissions and consents As part of the next phase of implementation, consents and permissions that will be required to progress the recommended conceptual design to detailed design and construction were identified along with potential risks to the project. These are described in Chapters 9 and 10, respectively.

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

2. Tatterford Common to Fakenham Mill Overview 2.1 Terminology and site location

2.1.1 Terminology To determine restoration options applicable to the River Wensum, the following terms are used: The term ‘unit’ is used only in reference to particular riverine SSSI units, which are officially demarcated sub-components of the River Wensum SSSI. These units, of which there are 9 within the study area (Units 46-54), are up to 20 kilometres in length. Each feasibility report looks at one SSSI unit, and this report addresses Unit 47 (River Wensum, Tatterford Common to Fakenham Mill). The term river ‘reach’ is used to describe smaller stretches of the river that have been defined according to their geomorphological environment. Whilst not related to the SSSI designation, a number of these reaches fall within each unit. This report recommends restoration options that may be appropriate to river Reaches 26 to 31. Due to their shorter length, reaches are considered preferable to units for planning restoration. The advantage of taking this approach is that many of the restoration options that apply to the entire unit can be broken down and assessed at an individual reach scale. The term ‘section’ has been used as a generic term referring to any portion of the river. For example, ‘the section of river between the bridge and the mill’. The term ‘option’ is used to describe a suite of measures that could be implemented to return Unit 47 to ‘unfavourable recovering’ or ‘favourable’ ecological condition. For example ‘Do nothing’, ‘Do minimum’, ‘River restoration’ and ‘Targeted maintenance’ are all options. The term ‘measure’ is used to describe a specific technique or work element that falls within an option. For example, bed raising is a measure of the ‘River restoration’ option and silt removal at mill ponds is a measure of the ‘Targeted maintenance’ option. 2.1.2 Site location This feasibility report addresses options for SSSI Unit 47, and Reaches 26 to 31. These are listed below in downstream to upstream order and shown in Figure 2.1.  Reach 26 – Fakenham Reach  Reach 27 – Hempton Reach  Reach 28 – Moor Reach  Reach 29 – Shereford Reach  Reach 30 – South Mill Reach  Reach 31 – Confluence Reach. It should be noted that the upstream limit of Reach 31 is not coincident with the upstream limit of SSSI Unit 47, which is delimited by the confluence of the River Tat and River Wensum. Reach 31 extends approximately 300m upstream of the confluence but is included in this report in its totality to prevent the need to cut short a defined reach length and to allow comparisons to be made with relevant reports (e.g. JBA, 2007).

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

This SSSI unit falls within the boundaries of North Norfolk District Council (NNDC). There are few settlements on this section of the River Wensum, other than Fakenham which is located at the downstream end of Unit 47.

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River Wensum Restoration Strategy Implementation SSSI Unit 46: Feasibility and Environmental Scoping Report

Figure 2.1 - Location of Reaches 26 to 31 within Unit 47

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

2.2 Previous works within Unit 47 Since its designation as a SSSI in 1993, there have been a variety of engineering and environmental surveys and investigations carried out on the River Wensum. In the past, some river restoration work has been carried out on Reaches 26 and 27. In addition, flood risk management work (other than routine maintenance) has been undertaken on reaches 26 to 29 within the unit since the mid 1990s. Restoration works are summarised in Table 2.1. Table 2.1- Summary of previous restoration works consented on Unit 47 (JBA, 2007)

Reach Location Previous Restoration Works Consented Year

31 Confluence Reach None identified. n/a

30 South Mill Reach None identified. n/a

None identified. (Flood defence maintenance works have been undertaken near Doughton Bridge to 29 Shereford Reach repair low spot on TLHB of River Wensum to 2002 prevent overtopping of water from the river into the adjacent IDB drain).

28 Moor Reach None identified. n/a

Hempton – riffles installed as mitigation for flood 2004 defence works upstream.

Hempton – meander reinstated as mitigation for flood defence works upstream. Previous channel 2003 27 Hempton Reach was also retained as ecological enhancement. Night Common – willow hurdles installed by fishing 1998 club.

Upstream Fakenham Mill – weeds transplanted by 1997 fishing club.

Fakenham Mill bank revetment and angling 26 Fakenham Reach platforms for disabled access along 130m of the 2001 TRHB.

In 2007, the RRC assessed some of the previous river restoration works with a view to judging their appropriateness (RRC, 2007). In this unit, the RRC visited and reviewed works done at Fakenham Mill, Goggs’ Mill and Hempton. The recommendations made by the RRC were used to select and specify restoration measures proposed in these RWRS reports. 2.3 RWRS restoration vision for Unit 47 A condition assessment of the SSSI was conducted by Natural England in 2010. All riverine SSSI units were recorded as being in ‘unfavourable no change’ condition. The vision of the RWRS is to provide a framework that leads to the delivery of restoration that improves the condition of SSSI units from their current ‘unfavourable’ condition towards a more naturally functioning and ecological sustainable system in ‘unfavourable recovering’ or ‘favourable’ ecological condition. The RWRS recommended a variety of restoration options for each reach. These are listed in Table 2.2.

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Table 2.2 - Recommended restoration measures for each reach in Unit 47 as provided in the RWRS (JBA, 2007)

Reach Length Restoration Recommendation from the RWRS (m)

Co-ordinate with flood risk management capital scheme – proposed works include raising of bank (e.g. raised footpath) along Hempton Road on right bank immediately upstream of the mill and individual protection of isolated properties on the left bank. There is clearly potential to co-ordinate this work with proposed lowering of mill controls. Discussions underway between Environment Agency and Natural England / JBA. Initial work required is for bed and bank stabilisation associated with lowering of Fakenham Mill structures at the downstream end of this reach. Appropriate measures required to manage silt deposits upstream of the mill. 26 464 Augment bed on average by 1.4m using local gravels wherever possible and create up to 11 gravel glides or riffles in this reach. The channel is on average 14.2m over wide and physically narrowing (with associated landscaping and fencing) may have to be considered to restore the full functioning of the channel in this reach following works at the mill. Adopt / maintain maintenance regime and riparian management and allow channel to create natural variations in local channel width and habitat niches. Post-project monitoring is required, especially in association with works at the mill.

Augment bed on average by 1.0m using local gravels wherever possible and create up to 43 gravel glides or riffles in the reach. The channel is on average 8.8m over wide and physical narrowing (with associated landscaping and fencing) may have to 27 1,720 be considered to restore the full functioning of the channel in this reach. Adopt / maintain maintenance regime and riparian management and allow channel to create natural variations in local channel width and habitat niches.

In the 100 to 200m downstream of Sculthorpe Mill and in the immediate scour pool area of good habitat value, no works are required and this area should be conserved and allowed to re-vegetate naturally. Reduce depth by an average of 28 1,245 0.6m and raise bed using up to 33 gravel glides or riffles in this reach. Assume reach will narrow naturally in time. Adopt / maintain maintenance regime and riparian management and allow channel to naturally narrow.

Initial work required is for bed and bank stabilisation associated with lowering of Sculthorpe Mill structures at the downstream end of reach. Appropriate measures required to manage silt deposits upstream of the mill. Augment bed on average by 0.5m using local gravels wherever possible and create up to 70 gravel glides or riffles in the reach. The channel is on average 9.1m over wide and physical 29 2,630 narrowing (with associated landscaping and fencing) may have to be considered to restore the full functioning of the channel in this reach following works at Sculthorpe Mill. Adopt / maintain maintenance regime and riparian management and allow channel to create natural variations in local channel width and habitat niches. Post- project monitoring is required, especially in association with works at the mill structure.

30 665 Restore section of channel.

Adopt / maintain maintenance regime and riparian management to allow channel to 31 457 develop a more natural form. However, assume reach will narrow naturally in time and that no bed raising is required.

These measures are relatively broad-scale and will require more detailed appraisal to determine the suitability and extent of each restoration measure. To appraise and define these measures, a detailed understanding of reach-specific baseline conditions is required. Chapter 3 of this report presents this baseline.

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

3. Environmental Baseline 3.1 Introduction This chapter presents environmental baseline information for Reaches 26, 27, 28, 29, 30 and 31. An environmental constraints map for Unit 47 is illustrated in Figure 3.1. A review of the existing environmental setting has been undertaken through a combination of desk study and preliminary site surveys. Data has been obtained from existing survey reports, and discussion with a number of individuals and organisations including Environment Agency internal functional specialists (e.g. Fisheries, Recreation and Biodiversity, National Environmental Assessment Service and Operations Delivery), Natural England, and Norfolk County Council (NCC). Information sources consulted include, but are not restricted to, the following:  The Environment Agency, www.environment-agency.gov.uk  North Norfolk District Council  Norfolk County Council, www.norfolk.gov.uk  Norfolk Rivers Internal Drainage Board (NRIDB)  Defra Multi-Agency Geographic Information for the Countryside, www.magic.gov.uk  Natural England, www.naturalengland.org.uk  Norfolk Mills, www.norfolkmills.co.uk  Norfolk County Council historic maps, www.historic-maps.norfolk.gov.uk  River Wensum Restoration Strategy (RWRS) JBA (2007)  Water Management Alliance  River Restoration Centre (Mant, J. & Fellick, A., 2007)  River Wensum Water Level Management Plan (Environment Agency, 2007)  Fakenham Flood Risk Assessment Phase 1 Ecological Survey (Halcrow, 2008b)  Environment Agency National Fisheries Monitoring Programme database. 3.1.1 Approach to presenting baseline information Presenting specific baseline information for each reach allows a better understanding of the existing environmental constraints that need to be considered when developing river restoration options. This information will be included in the options appraisal process and the Multi-Criteria Analysis (MCA). More information about the aims and objectives of the MCA is provided in Chapter 5. Baseline information common to environmental features across all reaches is described in Section 3.2 and Table 3.4, and baseline information specific to each reach is described in Tables 3.5 to 3.10. Figures 3.1 to 3.7 and supporting plates complement the baseline text. 3.1.2 Applicable environmental legislation and policy Environmental legislation that drives this project and will need to be considered alongside associated restoration and management options includes:  The Conservation (Natural Habitats &c.) Regulations 1994 (as amended).  The Wildlife and Countryside Act 1981 (as amended).

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

 The Conservation of Habitats and Species Regulations 2010.  The Eels (England and Wales) Regulations 2009. 3.1.3 Limitations to collating baseline information The baseline data has been derived from a review of existing information and preliminary walkover surveys. There are a number of gaps in the baseline data which will need to be addressed during the ongoing Environmental Impact Assessment (EIA) should restoration options identified in this report progress to the detailed design stage. 3.2 Common environment features across all reaches

3.2.1 Defining the character of chalk rivers A prominent feature of the cretaceous deposits of England is successive strata of chalk which dip gently to the west and are exposed along a wide front running roughly diagonally from Hampshire to Norfolk and Lincolnshire. In Norfolk, chalk strata predominate as the underlying geology. However, as one travels from Hampshire to Norfolk, the influence of the chalk on the land surface becomes increasingly masked by glacial and fluvio-glacial silts, sands, gravels and boulder clays. This reflects the fact that, even during the most severe glaciations over the Pleistocene period, the ice-sheets only extended as far south as the Thames and south of this, the landscape and river features are in closer contact with the underlying chalk layers. All chalk rivers are characterised by a high base flow throughout the year, with buffering of high flows during the winter as water percolates into the underlying aquifer, and buffering of low flows during the summer as water is gradually released from the aquifer. However, the influence of superficial deposits has a profound impact on how the chalk river habitat is expressed on the land. The southern chalk rivers such as the Hampshire Avon, the Frome, and the Test are regarded as ‘classic’ chalk rivers. In some of these, up to 90% of the flow enters the river through its bed, and as a consequence there is a low density of tributaries in the catchment. As these rivers lie very close to the chalk, there tends to be a relatively smooth pattern of flow accretion along the length of the river. Accretion tends to be greatest along those reaches with the highest gradient, and decreases as the river reaches the lower gradients typical of mature river and floodplain. The close association of the river bed to the chalk bedrock means that the headwaters are often winterbournes (watercourses which only flow in winter due to a seasonal increase in the water table). The way in which the chalk river is expressed is affected where the chalk is obscured and overlain by a considerable depth of superficial clays, sands and gravels. In most cases, it means that the chalk aquifer is separated from the river by one or more intermediate aquifers within the superficial deposits. Where the properties of the overlying drift change across the catchment, this results in a situation where tributaries from some sub-catchments more closely resemble chalk rivers than others. In situations where the land surface is less permeable, then there will tend to be a higher density of tributaries. Deep deposits of superficial material between the chalk and the land surface prevent the occurrence of winterbournes. Since northern chalk rivers run over material of varying permeability, so the level of accretion is more variable along different reaches. In Norfolk, the hydrology of chalk rivers is further complicated by the fact that the glacially scoured valleys in the chalk run north to south, whereas the rivers tend to run west to east. With northern chalk rivers the nature of the superficial deposits will also influence the proportion of water that reaches the river as overland flow, and also the material that is available to wash into the river and tributaries from rainfall. It will also affect the land use and hence the vulnerability to erosion of soils in the catchment. In Norfolk, intensive arable agriculture is more prevalent than in the south of England, and hence the river faces much greater vulnerability to diffuse water pollution from agricultural sources.

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Because Norfolk chalk rivers differ from their ‘classic’ counterparts in the south of England, restoration designs that are developed in the south of England may not necessarily be appropriate in Norfolk. The template for a Norfolk chalk river is explored in detail in the Geomorphological Appraisal of the River Wensum by Sear et al. (2006) and also summarised in the River Wensum Restoration Strategy (JBA, 2007). 3.2.2 The chalk river status of the River Wensum As a northern chalk river, the Wensum catchment is characterised by superficial deposits of sands, gravels and clays, resulting in a chalk river habitat which shows some affinities with other lowland river types. These deposits are variable in nature, and there tends to be greater permeability towards the north of the catchment, with other areas characterised by more impermeable clays. However, as with other chalk rivers, there is a very high base flow, and there is no ambiguity that this is a chalk river, with accretion from the aquifer throughout its length. The variability in overlying substrates, and complex underlying geology and landforms, results in the River Wensum exhibiting a higher density of tributaries than is characteristic of ‘classic’ chalk rivers. It also influences the availability of material that can be washed into the system during rainfall events, and some of the sub-catchments tend to accrete large volumes of sand. The system has been significantly impacted by the influence of intensive arable agriculture, which dominates much of the Norfolk landscape, and has lead to much higher vulnerability of soils to erosion than would have been the case post war, when Norfolk was characterised by a more mixed agricultural system. Whilst the Wensum retains its baseflow connectivity throughout its length, even to , the increasing thickness of the overlying glacial drift, sands and gravels along the lower catchment (downstream of Fakenham) increasingly dominates the physical character and structure of the river. As a result, the lower Wensum does not exhibit the characteristics of the classic southern England chalk rivers, where the underlying chalk is consistently closer to the river bed and influences the character of the river to a much greater degree. Another feature of the Wensum is that the river course reflects the periglacial conditions that prevailed immediately after the retreat of the last ice age. At this time the river was a high energy system with a wide meandering form that cut down into superficial deposits, creating a wide valley and floodplain within the landscape. The low energy system of later periods has modified this large-scale meandering system with secondary sinuosity within the floodplain. This pattern is well represented on the lower reaches of the river between Ringland and Hellesdon. As previously described, the impact of intermediate aquifers in the overlying deposits means that winterbournes are not expressed within the landscape in the way that they are in the ‘classic’ chalk rivers. Despite the majority of the Wensum floodplain remaining relatively natural and managed for grazing, the drainage of the catchment has been substantially altered over time by channel simplification, floodplain drainage and the presence of mills and their associated structures. The mill structures exert a disproportionate impact on the river, so that in many cases the Wensum behaves more like a series of linear lakes than a free-flowing river. A further complexity of impounded reaches is that it is no longer possible to drain the land directly into the river, and a secondary drainage system has been developed on the floodplain on either side of the river, draining back into the river immediately below the mill structures. This pattern is repeated at most of the 14 mill structures along the river, the arterial drains being managed by the Norfolk Rivers Internal Drainage Board. On free-flowing reaches, dredging activities have also had profound impacts on the river, resulting in channel deepening and removal of the gravel bed. The Geomorphological Appraisal demonstrated that the Wensum was such a low gradient system that it was unable to replace these gravels through natural processes, and the only mechanism through which the river is able to reduce the cross-sectional area of the channel is through the development of silt berms which result in a further narrowing and deepening of the system.

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Despite these changes, in 1980 Holmes classified sections of the upper river as Joint Nature Conservation Committee (JNCC) River Type III (chalk rivers and other base rich rivers with stable flows), with downstream transitions to Type I (lowland rivers with minimal gradients on mixed geology in England). In 2002, CAPM reclassified the upper reaches as Type IIIb to Iva (base rich / neutral impoverished rivers, normally close to source) and the lower reaches were similar to the middle reaches Type Ic to IIc, both of which demonstrated a degraded river type compared to previous surveys. As indicated in the previous section, it is essential to have a clear understanding of the characteristics of a Norfolk chalk river before developing detailed restoration designs. The studies carried out as part of the Geomorphological Appraisal, River Wensum Restoration Strategy and these feasibility assessments have enabled us to refine our knowledge and understanding of the expected form and function of the Wensum. 3.2.3 Historic environment There are two mills present in this unit; Fakenham Mill and Sculthorpe Mill (JBA, 2007). There are also two former mill sites, Goggs’ Mill and South Mill. Goggs’ Mill, which was demolished in the 1950s, stood 700m upstream of Fakenham Mill. Fakenham Mill and Sculthorpe Mill House are both Grade II listed buildings and there are numerous other listed buildings in the near vicinity of the river. There are two Scheduled Monuments to the south of the river at Hempton; the Fakenham Gasworks and the Remains of St Stephen’s Priory. There are a number of archaeological find sites recorded in the area. Recorded finds include Roman, medieval and post- medieval artefacts. The route of the disused Eastern and Midland Railway lies to the south of the River Wensum. Items of historical and cultural significance have been mapped for each reach and are shown in Figures 3.2 to 3.7, and where appropriate, described in detail within Tables 3.5 to 3.10. 3.2.4 Landscape character and visual amenity The Wensum valley is a shallow open valley characterised by the river and its floodplain. The valley provides long uninterrupted views to the adjacent patchwork of rolling open farmland and tributary farmland. Where present, trees tend to be in relatively small individual woodlands, often associated with sporting uses. Field boundaries are geometric and regular, but there are strong elements of less regular boundaries (North Norfolk Landscape Character Assessment, 2009). There are associated natural and human influenced features including wetland habitats, small- scale grazed pastures intersected by dykes and traditional built structures such as bridges and weatherboard mills. These features combine to create an intimate and varied landscape. Plates 1 to 19 illustrate some of the landscape character features associated with the River Wensum and its surrounding environment. North Norfolk District Council’s core strategy of its Local Development Framework outlines a policy to protect, conserve and, where possible, enhance landscape character with provisions for the settings of, and views from, Conservation Areas and Historic Parks and Gardens. The river passes through Fakenham Conservation Area at Fakenham. Raynham Park Historic Park is less than one kilometre to the south of the river at Reach 31. 3.2.5 Land use The land use tends to be arable on the valley sides with a mix of pasture, woodland and occasional fen and reedbed on the valley floor. In the upstream reaches land use is predominantly improved grassland for grazing sheep and cattle. Downstream, there are wet pastures, fens, reedbed and woodlands associated with the River Wensum SSSI and nature reserves managed by the Hawk and Owl Trust and Norfolk Ornithologists Association. The urban fringe of Fakenham extends into the north of the valley with residential, business and light industrial uses and there is a disused railway line on the valley side to the south. Outside the floodplain of the River Wensum much of the surrounding land is intensively farmed. Much of this includes cereal cropping, with potatoes and sugar beet in the rotation. It is the aim of

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

the England Catchment Sensitive Farming Delivery Initiative to reduce diffuse pollution from agriculture. Soil eroding from fields can enter watercourses through drains, ditches and via roads and ford crossings. Root crops are often grown on land that is at risk of soil erosion during periods of heavy rainfall when land is bare. Heavy machinery required to lift these crops may also lead to soil compaction. The majority of agricultural land within the unit is currently classified as Grade 3 (good to moderate quality land), with some Grade 4 (poor quality) lands, according to Defra’s Agricultural Land Classification system. The river and its valley fall within Environmentally Sensitive Area (ESA) scheme, which provides funding to land managers in support of traditional grazing management of permanent grassland including appropriate management of water levels. The ESA scheme is now closed to new applicants, and has been superseded by the Environmental Stewardship scheme. A number of terrestrial units of the River Wensum SSSI are present along Unit 47 (see Appendix D). This feasibility report has sought to improve the hydrological connectivity between the riverine and terrestrial SSSI units through the proposed measures outlined in Section 6 within the conceptual design. 3.2.6 River management The Environment Agency is the operating authority for the main channel of the River Wensum SSSI, with the exception of the section upstream of the confluence with the River Tat which is the responsibility of the Norfolk Rivers IDB. The IDB is the operating authority for a number of other watercourses (Main Drains) within the Water Level Management Plan (WLMP) area (Environment Agency, 2007). Responsibility for maintenance of “ordinary” watercourses rests with individual landowners. The Environment Agency operate an annual walk through inspection and undertake weedcutting (only on certain reaches), selective tree and shrub management (e.g. tree trimming to allow the passage of the weedcutting boat) and removal of fallen trees / obstacles causing unacceptable flood risk within Unit 47. The section of channel upstream of the Tat confluence, in Reach 31, is managed by the Water Management Alliance. IDB main channels are maintained according to their operational maintenance guidelines (NRIDB, 2007). 3.2.7 Water mills Water milling has historically taken place at 14 locations along the River Wensum. At six of these the mill buildings remain in use (residential), with most (but not all) of the mills being Grade II listed structures. In times of flood, mill owners may independently open their structures (if operable) as they see fit, with no consistent river-wide approach (Environment Agency, 2007). By retaining high water levels upstream, the mill structures have a major influence on the river. They have the potential to constrain the scope and effectiveness of river restoration, especially in sections of channel upstream of the mills. Unit 47 features the following mill sites:  Fakenham Mill (TF919 293)  Goggs’ Mill (TF912 396)  Sculthorpe Mill (TF892 302)  South Mill (TF881 282).

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Fakenham Mill (Plate 1) Technical details of the mill layout are given in the Water Level Management Plan (WLMP, Environment Agency, 2007). Key aspects are as follows:  There are 2 structures within the main channel; a penstock with steel gate and a fixed level weir. The gate is automated, and is either fully opened or fully closed depending on river conditions.  During normal (low) flow conditions, the gate is closed and water flows over.  During high flows the gate is opened, and water flows underneath.  Several water level triggers dictate the timing of gate operation.  There is a gauging station in the main channel. The buildings at Fakenham Mill have been converted to residential use. The water level control structures are owned and operated by the Environment Agency. The water rights are owned by the Environment Agency.

Plate 1 – Water level control structures upstream of Fakenham Mill

Goggs’ Mill (site of) Key aspects are as follows:  Weir and mill structure removed in 1954 by the East Norfolk Rivers Catchment Board. Sculthorpe Mill (Plate 2) Technical details of the mill layout are given in the WLMP. Key aspects are as follows:  The mill building is privately operated as a public house / hotel.  Main structure is a fixed weir. Historically boards have been used to control upstream water levels during weed cut operations. However these have recently been removed. There is no bypass channel.  The change in water level elevation due to removal of the boards is approximately 0.45m.  The water level control structures are privately owned.

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 The water rights are owned by the Environment Agency.  The boards are operated by the Environment Agency.

Plate 2 – Fixed weir structure at Sculthorpe Mill (with boards removed)

South Mill (site of) (Plate 3) Technical details of the mill layout are given in the WLMP. Key aspects are as follows:  There is no evidence of the mill building.  A fixed weir structure remains under the road bridge which provides only a small drop. There is no bypass channel.

Plate 3 – Downstream view from road bridge at site of South Mill

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A Mill Operating Protocol (MOP) for the River Wensum has been developed (Atkins 2010 draft), following consultation with owners and operators, to provide a unified approach to mill gate operation in support of the restoration strategy. The MOP is a first look at lowering of retained water levels, where this can be achieved through operational modifications only. Modelling has been undertaken to quantify the impact of board removal on the backwater extent at Sculthorpe Mill. The modelling showed no change in backwater extent compared to the Q90 flow (the flow that is equalled or exceeded for 90% of the time – i.e. a low flow. However, an unplanned removal of boards has shown a total elimination of any backwater effect. Summary information relating to the mill structures in Unit 47, as provided in the WLMP, is presented as Table 3.1. Table 3.1 - Mill details in Unit 47 (Environment Agency, 2007)

Mill Name Section Drop at Backwater Backwater Structure Length Structure Length Length Elevation (km)* (mean (mean flow), (% of section (m AOD) flow), (km) length (m) affected by backwater from mill)

South Mill 7.03** Negligible Negligible 0 38(est)

Sculthorpe Mill 2.69 1.16 1.44 53 36.8

Fakenham Mill 3.52 1.22 2.20 62 34.1 Notes * Distance to next mill upstream

* * to WLMP boundary upstream. 3.2.8 Soils and geology The predominant solid geology of the area is Chalk, a fine grained fissured limestone. The Chalk unit comprises Upper and Middle Chalk overlying Lower Chalk. The Chalk is underlain by the Gault clay, which consists of impervious grey clays. This in turn is followed by undifferentiated Carstone and Sandringham Sands. The Carstone comprises brown, ferruginous, well-jointed medium to coarse grained sandstones. The Sandringham Sands comprise brown, ferruginous fine grained sands which pass down to grey-green glauconitic sands and sandy clays. The predominant soil type occurring adjacent to the River Wensum in Unit 47 is a seasonally wet deep sand (Isleham). Smaller areas comprising of the Burlingham and Barrow loams occur in the areas around Shereford and Tatterford (additional references in Sear et al., 2006; JBA, 2007). In terms of ground contamination, chemical analysis of in-river silts was undertaken by JBA in 2007 (through the Environment Agency National Laboratory Service) at different points along the River Wensum. Data was generally collected upstream of mills, including South Mill, Sculthorpe Mill and Fakenham Mill in Unit 47. Soil guidance values were not exceeded except for levels of arsenic at South Mill. 3.2.9 Water Environment Water quality Routine Environment Agency water quality data is available for the River Wensum within Unit 47 at Sculthorpe Mill. The details of the water quality assessment conducted in 2008 at this location are shown in Table 3.2.

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Table 3.2 - Water quality (Environment Agency, 2010)

River Biochemical Ammonia Dissolved Ecological Nitrates Phosphates Stretch / Oxygen (mg N/l) Oxygen Status (mg/l) (mg/l) Location Demand (percentage (overall (mg/l) saturation) NTAXA & ASPT) Wensum: N/A A C A 5 3 Sculthorpe Key: Nitrates and phosphates - 1 to 6 (very low levels to very high levels); Chemistry and biology - A to F (very good to bad). NTAXA (Number of Taxa), ASPT (Average Score Per Taxon) biometrics used to calculate ecological status. Abstractions The Environment Agency (see Entec, 2010) has undertaken a Review of Consents (RoC) in the Wensum catchment (Regulation 50 of the Conservation (Habitats &c.) Regulations,1994). The report predicts impacts of licenced abstraction on the hydrological regime of River Wensum SSSI to identify whether these impacts are acceptable or unacceptable in terms of their effects on the ecology of the site. A Site Option Plan will identify any changes which the Environment Agency believes are necessary to ensure no adverse effect on site integrity and to achieve the RoC Stage 4 Environmental Outcomes, and will make general proposals as to how the changes could be achieved. To feed into this process the Environment Agency and carried out an aquatic macrophyte survey of the river (@OneAlliance, 2007). This study confirmed that all reaches of the River Wensum were capable of supporting ‘Ranunculus vegetation’, but that a number of components of this biotope were, at present, poorly represented. Review of Environment Agency GIS data (Environment Agency, 2009c) has identified one licensed surface water abstraction (7/34/11/*S/0272) for agricultural purposes located on Reach 29, together with a number of groundwater abstractions adjacent to, and upstream of, the reach. The single largest abstractor in the Wensum catchment is Anglian Water Services Ltd., taking groundwater from a number of boreholes, and a surface water abstraction at Costessey, for public water supply. Abstraction of surface water and ground water also occurs for agricultural needs, mainly summer spray irrigation (Environment Agency, 2007). . Surface water drainage The Norfolk Rivers IDB drains areas of agricultural and residential surface water run-off by using tributaries along the River Wensum. Local surface water flooding tends to occur in flashy rainfall events. This can be exacerbated in the event that main river flows overtop and water from the river drains into IDB drains which outfall near built-up urban areas. A wider initiative called the England Catchment Sensitive Farming Delivery Initiative (ECSFDI) was launched in 2005 and is being promoted by Natural England with the aim of raising awareness of diffuse water pollution and encouraging voluntary action from farmers to minimise the risks of diffuse pollution. The 50 priority catchments, including the Wensum, were identified jointly by the Environment Agency and English Nature, and cover about 40% of the agricultural area of England (with about 50,000 farmers, of which some 30,000 manage holdings of over 20 hectares in size). Catchments were identified using data gathered for Water Framework Directive (WFD) purposes on nitrate, phosphate and sediment pollution, combined with data on sensitive freshwater fisheries, chalk streams, failing bathing waters, groundwaters and SAC-designated lakes. The ECSFDI is also relevant to the achievement of the Government’s PSA target for the end of 2010 for 95% of SSSIs to be in ‘favourable’ or ‘unfavourable recovering’ condition. A specific sediment fingerprinting exercise, to distinguish different sources of sediment, is being undertaken on the River Wensum which is expected to be published in 2011. This may contain

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further baseline information which will input to the RWRS, in particular the strategy’s ecological improvement objectives. In much of the River Wensum, it is considered that diffuse pollution from agriculture comes from tributaries whereas the immediate floodplain does not pose such a threat. 3.2.10 Utilities At the time of submitting this report, information regarding utilities had not been obtained. This is a residual data gap, and more information will be collated should this unit progress to detailed design. 3.2.11 Condition of attributes in Unit 47 For units of river SSSIs to be regarded as in ‘favourable’ condition, targets on various attributes need to be met. Currently, Unit 47 is classified as ‘unfavourable no change’. The main reasons for the adverse condition of SSSI Unit 47, according to the condition survey undertaken by Natural England in 2010, are inappropriate water levels, inappropriate weirs dams and other structures, siltation, water abstraction, water pollution, agriculture / run-off and water pollution discharge (Table 3.3). Table 3.3 - Condition summary of Unit 47 attributes (Natural England, 2010)

Location European Features Siltation Chemical Water Quality Zone Riparian Water Levels Structures Biological Water Quality Channel Structure

River Wensum from U U U U U U F F River Tat confluence to Hempton Road bridge (Unit ID 1025551)

Key: U=Unfavourable’ F=Favourable

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Figure 3.1 - Environmental constraints on Unit 47

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Table 3.4 - Baseline information common to Unit 47

Environmental Baseline Information Feature

 Protected species recorded in this unit include otter, water vole and white-clawed crayfish (Environment Agency data from 1970s to present, Halcrow, Ecology 2008b). (Protected  Desmoulin’s Whorl Snail has been recorded from Reach 27 (Jackson & Howlett, 2000). Species)  The area is important for many bird species including lapwing, marsh harrier, kingfisher, little grebe, reed warblers and sedge warblers.

 The following terrestrial units of the River Wensum SSSI are located in the floodplain along Unit 47:  Unit 5: Dunton Farm.  Unit 6: Dunton Farm. Ecology (Statutory  Unit 7: Manor Farm Crisp. Designated  Unit 8: Sculthorpe Moor. Areas)  Unit 9: Fakenham, Fakenham Town Council.  Unit 10: Fakenham, R.C.Edmondson Ltd.  Unit 47: River Wensum.

 Floodplain Grazing Marsh (BAP Habitat) is prevalent along the reaches upstream of Sculthorpe Mill. Ecology (Non- Statutory  Areas of reedbed (BAP habitat) occur adjacent to the river. Designated  The river and adjacent land falls within the Broads ESA. Areas)  There are a number of County Wildlife Sites adjacent to the river along this unit. Further details are given in the baseline data for each river reach.

 Fisheries: Fish populations within this unit are dominated by brown trout, with bullhead and stone loach frequent. Brook lamprey, dace, eel, and three spined stickleback also occur. Roach are present in the impounded section immediately upstream of Fakenham Mill.  Invertebrates: Information is limited for this unit, confined mainly to the routine monitoring site at Sculthorpe Mill and a one-off sample from Doughton Road Bridge. Assemblages at the mill contain a number of rare or locally important species of caddisflies and stoneflies. Desmoulin’s whorl snail has been recorded in this river unit. A search on NBN gateway revealed that there are numerous species of dragonflies (including Southern, Brown and Ecology Migrant Hawkers; Emperor, Large Red and Hairy Dragonflies; Broad-bodied and Four-spotted Chasers; Black-tailed Skimmer; Ruddy and Common (Fisheries, Darters) and damselflies (Banded Demoiselle, Azure, Common blue, Red-eyed, Small red-eyed, Blue-tailed, Scarce emerald and Emerald) recorded Invertebrates & along this unit. Flora)  Flora: A wide variety of aquatic plants have been recorded including water crowfoots, water starwort, horned pondweed and unbranched and branched bur-reed. There are occasional records of fine-leaved and river water-dropworts (Environment Agency, 1995). Marginal areas are dominated by common reed, reed sweet-grass and canary reed-grass with associated wetland herbs.  IDB drains support a variety of aquatic and riparian or wetland plant species, some of conservation importance (such as lesser water parsnip) and provide complementary wetland habitats.

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Environmental Baseline Information Feature

 Japanese knotweed (Fallopia japonica) is present along the lower reaches of this unit (Atkins site observations, 2008 & 2010). Ecology  American mink have been recorded at various locations along the unit (EA data). (Invasive / Non- Native Species)  Canadian pondweed (Elodea canadensis) and monkeyflower (Mimulus spp.) were recorded throughout the unit in small, occasional patches during the 1995 River Corridor Survey (RCS) (Environment Agency, 1995).

 Willows (crack willow, sallow, osier, white willow, grey and goat willow) provide the majority of tree cover along the river corridor in this unit. Ecology (Trees)  Other species recorded include ash, hawthorn, elder, poplar and alder.

 Channel morphology has been altered to accommodate Fakenham and Sculthorpe Mills (and the former mill site at Goggs’ Mill). Most of the channel has been deepened, widened and straightened, with a number of former meanders now cut off from the present day river course. Some sections (e.g. part of Geomorphology Reach 29, upstream of Sculthorpe Mill) retain a good planform.  Adjacent floodplain wetlands have been extensively drained to provide grazing marsh or improved grasslands in the upper reaches.

 Environment Agency maintenance and flood risk management works have involved berm reductions, tree and debris clearance and silt removal. Previous  The Environment Agency has provided mitigation for flood risk works by installing gravel runs / riffles. Restoration  Angling clubs have managed aquatic plants and installed hurdles in some reaches. Works  Of most note is the reconnection of a former meander loop (Reach 27) upstream of the A1065 where installation of raised gravel bed areas was designed to encourage flows to divert along the meander.

 There are extensive areas of functional floodplain adjacent to the river. Flood Risk  Floodplain drainage to the river is predominantly via IDB Main Drains.  There are a number of properties in Hempton/Fakenham, and a few properties in Sculthorpe and Doughton, that are at risk of flooding.

 There is limited public access to this river unit.  Views of the river can be gained from the various road crossing points. Human  There is a footpath along the right bank of the river between Goggs’ Mill Road and Fakenham Mill. Environment  Free fishing is available along a section of the river upstream of Fakenham Mill.  Local nature reserves (e.g. Sculthorpe Moor) provide some access.  Canoeing takes place in the section of river upstream of Fakenham Mill

Historic  The disused route of the Eastern & Midland Railway (Lynn to Fakenham Railway, linking Gaywood near King’s Lynn to Norwich) is still evident across the Environment unit. The railway crossed the Wensum at Shereford.

 The unit is predominantly rural, with a few scattered properties in close proximity to the river. The majority of built development is associated with Land Use Fakenham at the downstream limit of the unit.

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Environmental Baseline Information Feature  The upper reaches are predominantly improved or semi-improved grassland for grazing sheep and cattle.  The lower reaches are less intensively managed for farming, and contain significant areas of reedbed, wet woodland and fen in addition to grazing marsh.

Traffic and  The A1065 is the only main road that crosses the river in this unit. Transport  All other road crossings are minor roads and lanes or foot crossings for farm access.

Utilities  No information available at present.

 The IDB maintain floodplain Main Drains and the River Wensum upstream of its confluence with the River Tat. River Maintenance  The Environment Agency undertakes permissive channel maintenance works, where required, to manage flood risk. Maintenance works may include de- silting, berm removal, weedcutting and tree or debris clearance.

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3.3 Environmental baseline for each reach within Unit 47 Specific baseline information for Reaches 26 to 31 is described in Tables 3.5 to 3.9 with accompanying Figures 3.2 to 3.7 and Plates 4 to 19.

Table 3.5 - Baseline information specific to Reach 26 (Fakenham Reach)

Environmental Baseline Information Feature

 Otter have been recorded at Fakenham Mill in 1998 (Environment Agency data). Ecology  Water vole have been recorded in this reach (in 2000) as this slow-flowing section provides ideal habitat (Environment Agency data). (Protected  Phase I surveys undertaken in 2007 (Halcrow 2008b) identified the best water vole habitat as being located immediately upstream of Fakenham Mill Species) where the Environment Agency has undertaken marginal habitat improvement works. Numerous field signs (feeding stations and latrines) were found along this reach upstream to Bridge Farm.

Ecology  There are no terrestrial units of the River Wensum SSSI on the floodplain adjacent to this river reach. (Statutory

Designated Areas)

 The reach falls within the Broads ESA. Ecology (Non- Statutory  There are two County Wildlife Sites adjacent to Reach 26: Designated  CWS 1277 (Land west of Oak Street, Fakenham). This consists of unimproved wet neutral grazing marsh, Areas)  CWS 1278 (Land adjacent to Fakenham sewage works). This comprises unimproved marshy grassland.

 Fisheries: Routine Environment Agency surveys conducted upstream of Fakenham Mill (2007) yielded a total of 9 fish species. These were; brown trout (Salmo trutta), bullhead (Cottus gobio), dace (Leuciscus leuciscus), eel (Anguilla anguilla), brook lamprey (Lampetra planeri), gudgeon (Gobio gobio), roach (Rutilis rutilis), 3-spined stickleback (Gasterosteus aculeatus) and stone loach (Barbatula barbatula). Trout were dominant in terms of density and standing crop, although good numbers of roach and dace were also recorded. The survey indicated the presence of two species of European interest, namely bullhead and brook lamprey. Ecology  Invertebrates: There are no Environment Agency routine survey sites along this reach and no other information is available. (Fisheries,  Flora: Invertebrates & Flora)  RCS (Environment Agency, 1995) and CAPM (2002) macrophyte survey: upstream of the mill patches of unbranched bur-reed were found, with occasional Canadian pondweed (Elodea canadensis) and fennel pondweed (Potamogeton pectinatus) and surface algae. Banks supported reed canary- grass (Phalaris arundinacea), reed sweet-grass (Glyceria maxima), water figwort (Schrophularia auriculata), yellow water lily (Nuphar lutea) great willowherb (Epilobium hirsutum) and meadowsweet (Filipendula ulmaria). The TRHB above the sluice was mown grassland, with silver birch and willows. Greater tussock sedge (Carex paniculata) was also found along the banks.  Upstream of the Bridge Farm access bridge the RCS survey (Environment Agency, 1995) recorded yellow water lily, watercress (Rorippa nasturtium- aquaticum), Canadian, fennel and curled pondweeds, with patches of unbranched bur-reed, reed sweet-grass, reed canary-grass, bittersweet (Solanum

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Environmental Baseline Information Feature dulcamara), greater tussock sedge, greater and lesser pond sedges (Carex riparia, C. acutiformis) and water forget-me-not (Myosotis scorpioides).

Ecology  Japanese knotweed is present along the TRHB. (Atkins observations 2008, 2010; CAPM, 2002; EA1995 RCS survey data). (Invasive / Non- Native Species)

 Riverside trees recorded in the RCS survey (Environment Agency, 1995) include elder (Sambucus nigra), alder (Alnus glutinosa), hawthorn (Crataegus Ecology (Trees) monogyna) , sycamore (Acer pseudoplatanus), box (Buxus sempervirens) and silver birch (Betula pendula). Willow scrub and tree species include white willow (Salix alba), goat and grey willows (S. caprea, S. cinerea), crack willow (S. fragilis), and osier (S. viminalis).

 This reach has been highly modified to provide water storage volumes for Fakenham Mill. Although the mill is now a series of private flats, the weir structure is still in place and the over-widened channel upstream provides deep, slow-flowing habitat. There are likely to be significant quantities of silt deposited in the section upstream of the weir as bed substrate of 100% silt was recorded by CAPM (2002) during macrophyte surveys. Geomorphology  The channel is considered to be around 14m over-wide and over 1m deeper than it would naturally be (JBA, 2007; BBR, 2003).  RHS conducted in 2007 upstream of Fakenham Mill (Halcrow, 2008b) concluded that the EA structures at Fakenham Mill have modified the river geomorphologically, with laminar flow resulting in little river turbulence and hence low stream power. This leads to.deposition of sand and other fine substrates. Flow velocities reduce near to the mill structures, resulting in the substrate being dominated by sand and silts.

Previous  In 2001 river restoration works included channel narrowing and silt removal. Restoration  In 2005 Fakenham Mill sluice gate was automated (in association with flood risk management works). Works

 Environment Agency web-based flood mapping indicates that properties and land to the north of the river are within Flood Zone 3 (I in 100 year floodplain). This includes the residential houses associated with Bridge Farm and the inter-connected ponds. Areas immediately to the south of the river Flood Risk are within Flood Zone 2 (1 in 1000 year floodplain - though this only affects industrial units and Back Street is not within the floodplain). Flood Zone 2 also reaches houses at the western edge of the main settlement area.

 This reach flows through the western outskirts of Fakenham with industrial premises and residential housing to the south of the river along Back Street and industrial units along Hempton Road. Human  To the north of the river channel are a number of private dwellings (Bridge Farm) with several inter-connected pools (a former trout farm) linked to the Environment River Wensum. Private gardens abut the TLHB of the river.  There is free fishing upstream of Fakenham Mill along the right hand bank. A number of fishing platforms are available for public use.  A footpath runs along the right hand bank of the river.

 A search on the Heritage Gateway for the central point of this reach indicated that within 1km there are: 93 listed buildings, 136 Norfolk Historic Historic Environment Records, 17 PastScape Records and 9 National Monuments Records for Excavation Index logs in the area. Environment  The most significant listed building is Fakenham Mill, located at the downstream end of the reach.  Fakenham Gasworks Scheduled Monument is located to the south of the river on the opposite side of Hempton Road.

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Environmental Baseline Information Feature

 The lower half of the reach is lined with mature trees. To the south lies Hempton Road, with an area of amenity land (mown grassland with trees) between the road and river. Land to the north is made up of private gardens. Land Use  At Bridge Farm, private properties and a series of ponds connected to the Wensum lie along the TLHB (to the north), with grazing marsh at the upstream end of the reach.  The TRHB land consists of industrial units and an increasingly wide strip of rough, unmanaged scrub and grassland towards the top of the reach.

Traffic and  Hempton Road lies along the southern bank (TRHB) of the lower half of the reach. Transport  The whole reach from Fakenham Mill to Goggs’ Mill is accessible by public footpath along its TRHB.

Utilities  No information currently available.

River  In-channel vegetation is cut by boat once a year. Selective tree and shrub management is also undertaken (e.g. tree trimming to allow the passage of Maintenance the weedcutting boat, and removal of fallen trees causing unacceptable flood risk).

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Figure 3.2 - Environmental baseline for Reach 26 (Fakenham Reach) Unit 47 Tatterford Common to Fakenham Mill_Final.docx 34

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Table 3.6 - Baseline information specific to Reach 27 (Hempton Reach)

Environmental Baseline Information Feature

 Desmoulin’s whorl snail were noted to be present along this reach in adjacent floodplain areas to the south of the river that provided suitable habitat, mainly Glyceria marsh and Phragmites swamp (Jackson & Howlett, 2000). Ecology  Water voles have been recorded along this reach (Environment Agency records up to 2001). Phase I surveys undertaken in 2007 (Halcrow, 2008b) (Protected identified water vole feeding stations near to Goggs’ Mill road bridge. Species)  White-clawed crayfish have been recorded at the A1065 road bridge (Environment Agency species records, up to 2001).  Marsh harrier and barn owl breed at Sculthorpe Moor Community Nature Reserve.

 There are 4 terrestrial units of the River Wensum SSSI on the floodplain adjacent to this river reach:  Unit 8: 13.16ha of broadleaved, mixed and yew woodland - lowland Ecology (Statutory  Unit 9: 1.41ha of fen, marsh & swamp – lowland Designated  Unit 10: 1.06ha of fen, marsh & swamp – lowland Areas)  Unit 11: 2.69ha of fen, marsh & swamp – lowland.  Further details, possible hydrological linkages, and appropriate actions are detailed in Appendix D.

 County Wildlife Sites: There are two CWS adjacent to Reach 27: CWS 1277 (Land West of Oak Street, Fakenham). This consists of unimproved wet neutral grazing marsh, Ecology (Non- CWS 2139 (Sculthorpe Moor and Meadows).This is an extensive site lying to the west of Fakenham (86.8ha). The River Wensum SSSI divides the site, Statutory and a significant area of the moor itself forms part of the SSSI. A number of different habitat types occur including unimproved, neutral marshy grassland Designated adjacent to the river, secondary woodland, wetland areas and pools, scrub, unimproved acidic marshy grassland and drier areas characterised by coarse Areas) grasses with gorse.  The reach falls within the Broads ESA  Areas of Hempton Moor and Night Common are Registered Common Land (MAGIC).

 Fisheries: No routine fisheries data is collected as part of the Environment Agency’s National Fisheries Monitoring Programme along Reach 27.  Bullhead and brook lamprey have been recorded at Goggs’ Mill bridge (Environment Agency records up to 1997).  Brook lamprey have been recorded between 1983-97 (upstream of Fakenham Mill). Ecology (Fisheries,  Native brown trout are frequent within the reach. Invertebrates &  Invertebrates: There are no Environment Agency macroinvertebrate routine sampling sites or other information available along this reach. Flora)  Flora: The RCS survey (Environment Agency, 1995) recorded aquatic plants such as unbranched bur-reed, fennel pondweed, algae (Vaucheria spp. and Cladophora agg.), fool’s water-cress (Apium nodiflorum), water-cress, water milfoil (Myriophyllum spicatum), blue water-speedwell (Veronica anagalis- aquatica), Canadian pondweed, yellow flag iris (Iris pseudacorus), common reed (Phragmites australis), occasional water starwort (Callitriche spp.) and branched bur-reed (Sparganium erectum). The upper section of this reach also supported horned pondweed, pink water speedwell (Veronica catenata), Unit 47 Tatterford Common to Fakenham Mill_Final.docx 35

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Environmental Baseline Information Feature brooklime (Veronica beccabunga) and curled pondweed.  Riparian and adjacent areas supported carnation sedge (Carex panacea), greater tussock and greater pond sedges, great willowherb, reed sweet-grass, marsh thistle (Cirsium palustre), meadowsweet, greater pond sedge, hemp agrimony (Eupatoria canabinum), water figwort and extensive areas of common reed.

Ecology  Japanese knotweed is present along the TRHB in the section downstream of Goggs’ Mill Road Bridge. (Invasive / Non- Native Species)

Ecology (Trees)  RCS surveys (Environment Agency, 1995) noted poplars, willows (S. fragilis, S. alba, S. viminalis), alders, elders and oaks (Quercus robur).

 The channel has been extensively widened, straightened and deepened with substantial removal of gravel bed layers to the extent that it is now Geomorphology considered to be 1m over deep and 8.8m too wide.

 1997: Aquatic weeds were transplanted by the local fishing club. Previous  1998: Willow hurdles were installed by the fishing club at Night Common. Restoration Works  2003-2004: A former meander section was re-connected (upstream of the A1065 road bridge) as mitigation for flood defence works, with installation of gravel riffles in the main channel.

 The Environment Agency web-based flood maps indicate that the majority of the fluvial floodplain is to the north of the river, across Sculthorpe Fen (Flood Zone 3). Flood Risk  Flood Zone 2 extends both sides of the river channel, up to the former railway to the south and extending to Fakenham Road to the north. A few properties along Hayes Lane are within this flood zone area.

 There are few properties along this reach and most of the surrounding land is marshland, fen, wet grassland and wet woodland. Human  The downstream end of the reach is crossed by the A1065 and the former Goggs’ Mill road. Environment  The TRHB upstream of the A1065 is fished by Fakenham Angling Club.  Parking and local access to the river is available at Goggs’ Mill Road.

 Within 1km of the centre-point of the reach, the Heritage Gateway has 5 records of listed buildings, 24 Norfolk Historical Environment Records and 5 PastScape records.  The remains of St Stephen’s Priory Scheduled Monument lie to the south of the river.  St Andrews Church and Hempton Monument (which is no longer standing, possibly in ruins by 1495). Finds include fragments of tiles, walls, old ponds Historic and a possible moat. Environment  Several finds of archaeological importance dating from pre-historic to post-medieval periods have been made across the area, including Roman coins, flint, pottery, buckles, harness fragments and axe heads.  To the south of the River Wensum lies the route of the disused Eastern & Midland Railway (Lynn to Fakenham Railway, linking Gaywood near King’s Lynn to Norwich).

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Environmental Baseline Information Feature

 TLHB areas consist of common reed swamp, marshland with pools and ditches, semi-natural broadleaved woodland, plantation and semi-improved poor grassland. Land Use  TRHB areas contain marshy grassland, semi-improved grassland, plantation and mixed woodland.  IDB drains run alongside the Wensum on both sides of the river.  Parts of the TLHB are managed as nature reserves by the Hawk and Owl Trust and Norfolk Ornithologists Association.

 The A1065 road bridge and Goggs’ Mill Road cross at the downstream end of the reach. Traffic and transport  There are no formal public footpaths upstream of Goggs’ Mill Road. There is a footpath for a short distance downstream of Goggs’ Mill Road on the left bank, and a longer section of path (all the way to Fakenham Mill) along the right bank.

 An electricity substation is located to the south of the river. Utilities  No further information currently available.

 In-channel vegetation is cut by boat once a year in the section of river between the downstream end of Reach 27 and Goggs’ Mill. Vegetation in the River upstream section of the reach is cut by boat if required. Selective tree and shrub management is also undertaken (e.g. tree trimming to allow the maintenance passage of the weedcutting boat, and removal of fallen trees causing unacceptable flood risk).

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Figure 3.3 - Environmental baseline for Reach 27 (Hempton Reach) Unit 47 Tatterford Common to Fakenham Mill_Final.docx 38

River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Table 3.7 - Baseline information specific to Reach 28 (Moor Reach)

Environmental Baseline Information Feature

 There are records of otter around Sculthorpe Mill (Environment Agency data with records between 1992 and 1996). Ecology  White-clawed crayfish have been found at the mill (Environment Agency records between 1996 and 2001) and noted in EA routine macroinvertebrate (Protected samples at Sculthorpe Mill during 2003 and 2009. Species)  Grey wagtail breed in the vicinity of Sculthorpe Mill.

Ecology  There is one terrestrial unit of the River Wensum SSSI on the floodplain adjacent to this river reach: (Statutory Unit 8: 13.16ha of broadleaved mixed & yew woodland – lowland (at the extreme downstream end of the reach) Designated Areas)

 There is one CWS adjacent to Reach 28: Ecology (Non-  CWS 2139 (Sculthorpe Moor and Meadows) (see Table 3.6 for further details). Statutory Designated  The reach is within the Broads ESA. Areas)  Land adjacent to the TRHB is classified as Floodplain Grazing Marsh (BAP Habitat).

 Fisheries: No routine fisheries data is collected as part of the Environment Agency’s National Fisheries Monitoring Programme along Reach 28.  Bullhead have been recorded by the Environment Agency near Sculthorpe Mill (up to 2001) and brook lamprey have been recorded at Sculthorpe Moor (1983). Good numbers of trout were observed in the free-flowing reach downstream of Sculthorpe Mill during the Atkins site visit in August 2010.  Invertebrates: Sculthorpe Mill is a routine Environment Agency macroinvertebrate monitoring site. It was also sampled during a special macroinvertebrate survey of the Wensum in 2001 by Stansfield et al. The sample site is downstream of the mill structures where there is shallow, fast flowing water over clean gravel. Species of interest that have been recorded include the beetle Anacaena bipustulata, leech Erpobdella testacea, white- clawed crayfish, cased caddis Baraeodes minutus, Apatina muliebris, Mystacides nigra, Silo nigricornis and Lepidostoma hirtum and the stonefly Ecology Nemoura avicularis. (Fisheries,  Flora: RCS surveys (Environment Agency, 1995) and CAPM 2002 macrophyte surveys recorded common reed as a frequent and dominant marginal Invertebrates & feature of this reach, within which grows water forget-me-not, watercress, bittersweet, hemlock, great willowherb, reed sweet-grass, water mint, blue Flora) water-speedwell and reed canary-grass. In-channel vegetation included patches of unbranched and branched bur-reed, fennel pondweed, and occasional clumps of water starwort, Canadian pondweed, blue water-speedwell, water-cress, fool’s water-cress, shining pondweed (Potamogeton lucens), occasional horned pondweed and water crowfoot (Ranunculus fluitans). Algae included Vaucheria spp and Cladophora agg. Shallower sections towards Sculthorpe Mill support fennel pondweed, spiked water milfoil, horned pondweed, curled pondweed, water crowfoot and aquatic moss (Amblystegium riparium), with unbranched bur-reed in deeper areas just below the mill. River water dropwort (Oenanthe fluviatilis) was also recorded (in RCS reach WENS007).  Adjacent IDB drains supported common reed (choking in places), greater pond sedge and spiked water milfoil, reed sweet-grass, water starwort, blue water-speedwell, water plantain, gipsywort, meadowsweet and soft rush (Juncus effusus).

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Environmental Baseline Information Feature

Ecology  None were recorded in data from the 1995 RCS or 2002 CAPM surveys (Invasive / Non- Native Species)

 Land adjacent to the TLHB of the Wensum is largely broadleaved woodland and plantation (Moor Plantation and Sculthorpe Moor). These areas also Ecology (Trees) support wet woodland ground flora. Tree species include poplars, alder, willows, elder, ash and oak.  TRHB is fringed by trees (crack willow, elder, sallow, alder, ash, silver birch, white willow and hawthorn).

 The lower section of the reach is wide and deep.  The mid-section contains riffles but is mostly wide, deep and slow-flowing with encroachment by common reed at the margins. Part of this reach is embanked along the TRHB (possibly dredged channel material). Geomorphology  The section downstream of Sculthorpe Mill supports several riffles, shallow runs and clean gravel habitats, but is embanked for much of its length.  This reach is likely to be a diverted section of the natural river route constructed to supply water to the mill. The original course of the river may have run to the south of Sculthorpe Mill, along a channel that is now occupied by an IDB drain.

Previous  None. Restoration Works

 Sculthorpe Moor and Moor Plantation provide substantial flood storage areas (Flood Zone 3), as does the grazing land to the south-east of Sculthorpe Flood Risk Mill.  A number of properties in the vicinity of Sculthorpe Mill are at risk of flooding.

Human  In addition to Sculthorpe Mill there are a few residential buildings at the upstream limit of the reach. Environment  Shereford Road runs 200m to the south of the main river channel between Shereford and Hempton.

 A Heritage Gateway search of 1km from the mid-point of the reach found 5 listed buildings, 20 Norfolk Historical Environment Records and 4 PastScape records. Historic  Sculthorpe Mill House is listed, dated to 1759 with several later character additions. Environment  Roman objects, various Medieval and post-medieval finds, have been recorded in and around Sculthorpe.  To the south of the River Wensum lies the route of the disused Eastern & Midland Railway (Lynn to Fakenham Railway, linking Gaywood near King’s Lynn to Norwich).

 TLHB: Large-scale broadleaved woodland and plantation, together with some grassland. Some built development in proximity to Sculthorpe Mill. Land Use  TRHB: Marshy grassland in the upper and mid-reach section. Semi-improved, poor grassland (cattle grazed) in the lower section.  Parts of the reach were noted as supporting extensive wetland, woodland and carr (CAPM, 2002).

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Environmental Baseline Information Feature

Traffic and  Shereford Road is located 200m south of the river, whilst an access road links Sculthorpe Mill to the A148, 650m to the north. Transport  There is a traditional ford crossing just downstream of Sculthorpe Mill.

Utilities  No information currently available.

River  In-channel vegetation is cut by boat once a year if required. Selective tree and shrub management is also undertaken (e.g. tree trimming to allow the Maintenance passage of the weedcutting boat, and removal of fallen trees causing unacceptable flood risk).

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Figure 3.4 - Environmental baseline for Reach 28 (Moor Reach) Unit 47 Tatterford Common to Fakenham Mill_Final.docx 42

River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Table 3.8 - Baseline information specific to Reach 29 (Shereford Reach)

Environmental Baseline Information Feature

 Otter were recorded between Southmill Bridge and Dunton (1998 Environment Agency data).

Ecology  Bullhead were recorded at South Mill and Doughton Bridge (Environment Agency data to 1997). (Protected  Brook lamprey were recorded at South Mill and Doughton Bridge (Environment Agency data 1997) and are still present (see fisheries section below). Species)  White-clawed crayfish were recorded at South Mill in 2003 (Environment Agency, 2004) and Doughton Bridge (1997 Environment Agency data).  Lapwings (Vanellus vanellus) were noted to be on poor grassland areas adjacent to the TLHB during the 1995 RCS (Environment Agency, 1995).

 There are 3 terrestrial units of the River Wensum SSSI on the floodplain adjacent to this river reach: Ecology  Unit 5: 4.63ha of fen, marsh & swamp – lowland (Statutory Designated  Unit 6: 3.53ha of fen, marsh & swamp – lowland Areas)  Unit 7: 2.64ha of neutral grassland – lowland.  Further details, possible hydrological linkages, and appropriate actions are detailed in Appendix D.

 There are three CWS adjacent to this reach; CWS 2139 (Sculthorpe Moor and Meadows) (see Table 3.6 for further details) CWS 1266 (Land South of Shereford Common).  This site is an area of improved marshy neutral pasture adjacent to the River Wensum. The eastern part of the site is heavily grazed and has few herbs excepting marsh thistle (Cirsium palustre). Closer to the River Wensum the ground is highly poached, but the flora is more diverse. Typical species present include nettle (Urtica dioica), meadow grass (Poa sp.), cock’s-foot (Dactylis glomerata), meadow Ecology (Non- buttercup (Ranunculus acris), and great willowherb (Epilobium hirsutum), as well as oat-grass (Avenula spp.) and Yorkshire fog (Holcus Statutory lanatus). There were single spikes of common spotted-orchid (Dactylorhiza fuchsii) and cuckooflower (Cardamine pratensis). Designated Areas) CWS 1267 (Shereford Common).  This site is rough semi-improved, marshy neutral grassland adjacent to the River Wensum. The meadow is dominated by Yorkshire fog, oat-grass, cock’s-foot and rosebay willowherb (Chamerion angustifolium) which is found in small areas. These are interspersed with meadowsweet (Filipendula ulmaria), silverweed (Potentilla anserina), lesser stitchwort (Stellaria graminea), and wild angelica (Angelica sylvestris). There is a small pond in the north which is dominated by soft rush (Juncus effusus) and jointed rush (Juncus articulosus).  The reach is within the Broads ESA.  Land both sides of the main channel is classified as Floodplain Grazing Marsh (BAP Habitat).

Ecology  Fisheries: An Environment Agency survey conducted downstream of Southmill Farm in 2007 yielded a total of 6 fish species; brown trout (Salmo trutta), (Fisheries, bullhead (Cottus gobio), dace (Leuciscus leuciscus), eel (Anguilla anguilla), brook lamprey (Lampetra planeri) and stone loach (Barbatula barbatula). Invertebrates & Trout, bullhead and stone loach were the most abundant species, with trout occurring at the greatest density and standing crop. Flora)  Invertebrates: Doughton Bridge was sampled in 2001 as part of the special survey by Stansfield et al. (2001). The bed substrate was noted to be sand-

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Environmental Baseline Information Feature dominated and the most interesting species identified in the sample was the stonefly Leuctra fusca.  Flora: The RCS (Environment Agency, 1995) and CAPM 2002 macrophyte surveys recorded unbranched bur-reed, fennel pondweed, horned pondweed, spiked water milfoil, water starwort, opposite-leaved pondweed (Groenlandia densa) and occasional perfoliate pondweed (Potamogeton perfoliatus) water crowfoot (Ranunculus aquatilis and R. penicillatus) and moss (Rhynchostegium riparioides). Marginal areas were dominated by common reed, with blue water-speedwell, water-cress, fool’s water-cress, reed sweet-grass, branched bur-reed, water mint, pink water-speedwell and bittersweet. Algae (Vaucheria spp. and Cladophora agg.) were present, along with a few small patches of moss (Amblystegium riparium). Shallower water downstream of Southmill Farm (RCS reach WENS002) supported horned pondweed, fennel pondweed, fine-leaved and river water dropworts (Oenanthe aquatica and O. fluviatilis), pink water speedwell, water starwort, curled pondweed and water crowfoot, with unbranched bur-reed in deeper areas. Shallow berms supported water forget-me-not, brooklime and blue water-speedwell.  Bank vegetation consisted of common reed, great willowherb, hemlock, nettle, occasional tussock sedge, water figwort, hemp agrimony and reed canary-grass.  RCS (Environment Agency, 1995) data recorded the IDB drains as supporting common reed with brooklime, water-cress, reed sweet-grass, hard rush, ragged robin, creeping buttercup, bristle club-rush, cyperus sedge (one record) and devil’s bit scabious. Adjacent land supported fen bedstraw, water avens, carnation sedge, valerian, marsh arrowgrass (Triglochin palustris) (one record) and nodding bur-marigold.

Ecology  American mink have been recorded at Southmill Bridge (1996 Environment Agency data) and around Dunton (1997 Environment Agency data). (Invasive / Non- Native Species)

 Willows (sallow, white, crack, osier), poplars, lilac (by Sculthorpe Mill), alder, elder and hawthorn are present along this reach. Occasional fallen trees Ecology (Trees) were also noted along the river banks (1995 RCS; CAPM 2002).

 At Shereford, the 1995 RCS (reach WENS005) noted there was upwelling flow within a deep, wide section. Geomorphology  Although much of the reach has been deepened, straightened and widened, there remain some sections with a meandering planform which have been less modified, notably in the section downstream of Manor Farm. These sections have a gravel bed and support diverse aquatic plant communities.

Previous  None. Restoration Works

 Environment Agency web-based flood mapping indicates that this reach has extensive areas of Flood Zone 3 along the river’s course with small Flood Risk extensions for extreme flood events (Flood Zone 2). Properties at risk include Sculthorpe Mill and property at Doughton Bridge.  The roads at Doughton Bridge and towards Sculthorpe Mill are prone to flooding.

Human  The river is fished by a private syndicate. Environment

Historic  A Heritage Gateway search for 1km around the centre-point of this reach found 4 listed buildings (Manor Farmhouse, St Peter’s Church, St Nicholas Environment church and Sculthorpe Mill House), 21 Norfolk Historical Environment Records (including finds dating from pre-historic times to Roman, medieval and post-medieval finds and features, many in Dunton and Shereford), 5 PastScape records (including the listed buildings, medieval settlement at Doughton

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Environmental Baseline Information Feature and Roman finds) and 2 National Monuments Record Excavation Index records.  to Toftrees Roman Road crosses the river running north-south, upstream of Sculthorpe Mil,l and is a recorded ‘Road Monument’.  The former Eastern & Midland Railway crosses the river through Shereford and runs close to the west of the river through Doughton.

 Broadleaved woodland (dominated by willows) and patchy trees line the bank top along much of this reach and an IDB drain runs parallel along most of the TLHB in the lower sections.  TLHB: Upstream of Sculthorpe Mill, broadleaved woodland and improved grassland (cattle grazed) on the floodplain, leading to arable fields on the higher land. Further upstream is a mixture of marshy grassland and reed swamp, poor and improved cattle pasture and broadleaved semi-natural Land Use woodland.  TRHB: Upstream of Sculthorpe Mill is a public road and beyond is marshy grassland and improved grassland. Horse and cattle pasture, mixed woodland plantation, amenity grassland, marshy grassland and arable land (away from the valley bottom) broadleaved semi-natural woodland and dense scrub occur further upstream (descriptions taken from 1995 RCS (Environment Agency, 1995) and CAPM 2002 survey forms, Ordnance Survey mapping and aerial photographs).

Traffic and  The river is accessible by road at three main points, namely Southmill Farm, Doughton Bridge and Sculthorpe Mill. Transport

Utilities  Limited information currently available. Overhead telephone lines follow the right bank of the river upstream of Sculthorpe Mill.

 If required, in-channel vegetation is cut once a year by boat in the section of channel between Sculthorpe Mill and Doughton Bridge. Weedcutting on this reach is not always possible, being dependent on sufficient depth of water to float the weedboat. Selective tree and shrub management is also River undertaken (e.g. tree trimming to allow the passage of the weedcutting boat, and removal of fallen trees causing unacceptable flood risk). Maintenance  An annual walk through inspection takes place on the section of the reach between Doughton Bridge and South Mill Farm. Tree trimming is undertaken when required. Obstacles in the channel are removed if they cause an unacceptable flood risk.

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Figure 3.5 - Environmental baseline for Reach 29 (Shereford Reach) Unit 47 Tatterford Common to Fakenham Mill_Final.docx 46

River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Table 3.9 - Baseline information specific to Reach 30 (South Mill Reach)

Environmental Baseline Information Feature

Ecology  Otter have been recorded at Southmill Bridge (1997 Environment Agency data). (Protected  Bullhead and brook lamprey have been recorded at Southmill Farm (Environment Agency data up to 1997) (see also fisheries section below). Species)  White-clawed crayfish have been recorded at Southmill Farm (Environment Agency data to 1997 & Environment Agency, 2004).

Ecology  There are no terrestrial units of the River Wensum SSSI on the floodplain adjacent to this river reach. (Statutory Designated Areas)

Ecology (Non-  County Wildlife Sites: There are none adjacent to this reach. Statutory  The reach is within the Broads ESA. Designated Areas)  Much of the land beside the river is Floodplain Grazing Marsh (BAP Habitat).

 Invertebrates: There have been no invertebrate samples collected along this reach.  Flora: The RCS (Environment Agency, 1995) and CAPM 2002 macrophyte surveys found abundant water starwort, occasional water crowfoot, unbranched bur-reed, fennel pondweed, horned pondweed, and opposite-leaved, curled and perfoliate pondweeds. River water dropwort was recorded Ecology upstream of Southmill Bridge. (Fisheries, Invertebrates &  Emergent vegetation consisted of water forget-me-not, branched bur-reed, blue water-speedwell, water mint, fool’s water-cress, water-cress, water Flora) plantain, lesser pond sedge and reed sweet-grass. Bank vegetation consisted of great willowherb, nettle, hemp agrimony, water figwort, meadowsweet, reed canary-grass and occasional tussock sedge.  IDB drains supported branched bur-reed, reed sweet-grass, water mint, valerian, thread-leaved water crowfoot (Ranunculus trichophyllus) and lesser water parsnip (Berula erecta) (Environment Agency, 1995).

Ecology  American mink have been recorded at Southmill Bridge (1996 Environment Agency data). (Invasive / Non- Native Species)

 This reach is largely devoid of trees except for clumps of crack willow and elder at its downstream end, and alders, hawthorn and crack willows at its Ecology (Trees) upstream end (1995 RCS and aerial photographs (Multimap).

 This is an altered section of river that is far removed from its original course. This may have been multiple channels across flat ground or meandering Geomorphology along the route of what is now the IDB drain across the floodplain to the north and fed by numerous spring flows from adjacent areas.  The underlying chalk layers are much closer to ground level within the upper Wensum due to a thinner overlay of glacial drift deposits.

Previous  None. Restoration Works

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Environmental Baseline Information Feature

 There are no properties at risk of flooding along this reach. Flood Risk  There are extensive areas of functional floodplain (mostly grazing marsh) to either side of the river.

Human  Southmill Farm and adjacent buildings are the only dwellings along this short reach. Environment

 A Heritage Gateway search found no listed buildings within 1km of the reach mid-point, but found 5 Norfolk Historic Environment Records (including prehistoric, iron age, Roman, Saxon, medieval and post-medieval finds and a ring ditch) and 2 National Monument Records Excavation Index data (same Historic two sites as for Reach 29 at St Nicholas Church and The Street in Shereford). Environment  Palaeochannels across the floodplain are likely to be present along this reach as the flow route of the Wensum has been radically altered and simplified.  The route of the former Eastern & Midland Railway runs to the west of the river, beyond the limit of the floodplain.

Land Use  Predominantly improved pasture, interspersed with drainage networks. Higher land is used for arable cropping (Environment Agency, 1995).

Traffic and  An unnamed road crosses at the downstream end, at Southmill Farm, and is the only point of access for this reach. transport  There are no public footpaths or rights of way along this reach according to Ordnance Survey mapping.

Utilities  No information currently available.

River  The Environment Agency undertake an annual walk through to inspect the river. Tree trimming is undertaken when required. Obstacles in the channel maintenance are removed if they cause an unacceptable flood risk.

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Figure 3.6 - Environmental baseline for Reach 30 (South Mill Reach) Unit 47 Tatterford Common to Fakenham Mill_Final.docx 49

River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Table 3.10 - Baseline information specific to Reach 31 (Confluence Reach)

Environmental Baseline Information Feature

Ecology  White-clawed crayfish remains have been recorded at the confluence with the River Tat (EA site visit, 2005). (Protected Species)

Ecology  There are no terrestrial units of the River Wensum SSSI on the floodplain adjacent to this river reach. (Statutory Designated Areas)

 There is one CWS adjacent to Reach 31: Ecology (Non-  CWS 1265 (Tatterford Common). This 7.1ha site is an area of tall herb vegetation adjacent to the River Tat, together with woodland. The east Statutory of the site is mixed emergent vegetation with scattered scrub. The area to the west is dominated by deciduous woodland. Designated Areas)  This reach is within the Broads ESA.  Land both sides of the river is classified as Floodplain Grazing Marsh (BAP Habitat).

 Fisheries: No routine fisheries data is collected in Reach 31 as part of the Environment Agency’s National Fisheries Monitoring Programme.  Invertebrates: No routine or individual macroinvertebrate samples have been collected from this reach. Ecology  Flora: The RCS (Environment Agency, 1995) covers the section of channel from the downstream end of the reach as far as the confluence with the River (Fisheries, Tat. Aquatic plants included fennel pondweed and patches of horned pondweed. Greater tussock sedge was noted along the bank top and the river Invertebrates & margins supported common reed, water figwort, great willowherb and reed canary-grass. There is no RCS information for the remainder of the reach, Flora) upstream of the Tat confluence.  The 2002 CAPM macrophyte surveys recorded fool’s water-cress, common reed, branched bur-reed, blue water-speedwell, water starwort, reed sweet- grass, water forget-me-not, reed canary-grass, hemp agrimony, water dropwort, water-cress, brooklime and horned pondweed.

Ecology  No information currently available. (Invasive / Non- Native Species)

Ecology (Trees)  At the lower end of the reach, below the Tat confluence, crack willow, sallow and hawthorn were noted in the RCS (Environment Agency, 1995).

 This section retains much of its sinuosity, though the adjacent floodplains have been drained for grazing. Geomorphology  Adjacent floodplain contains palaeochannels and remnant wetland features including ponds.

Previous  None. Restoration Works

Flood Risk  There are no dwellings within the floodplain along this reach.

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Environmental Baseline Information Feature  There is an extensive area of functional floodplain adjacent to the left bank along this reach.

Human  There are no properties within this reach and the site is inaccessible to the general public. Environment

Historic  The route of the former Eastern & Midland Railway runs to the west of the river, beyond the limit of the floodplain, crossing the River Tat 280m upstream Environment of the confluence with the River Wensum.

 Improved grazing marsh along both banks of the river. Land Use  Further south-east the higher land is farmed for arable crops and there are two areas of woodland (Dark Wood and Pig’s Pond Plantation).

Traffic and  There are no roads or footpaths along this reach. transport

Utilities  No information currently available.

 The Environment Agency undertake an annual walk through to inspect the river between the downstream end of Reach 31 and the Tat confluence. Tree River trimming is undertaken when required. Obstacles in the channel are removed if they cause an unacceptable flood risk. The section of channel upstream maintenance of the Tat confluence is managed by the Norfolk Rivers Internal Drainage Board.

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Figure 3.7 - Environmental baseline for Reach 31 (Confluence Reach)

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Plate 4 – Reach 26: Fakenham Mill automated sluice and gauge

Plate 5 – Reach 26: River Wensum on approach to Fakenham Mill. Emergent vegetation (right bank) was installed as river edge enhancement in 2001 (NGR TF91792 29296, August 2010)

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Plate 6 - Reach 26: Upstream of Fakenham Mill with over-wide and deep river section (Hempton Road to the right)

Plate 7 – Reach 27: River Wensum looking downstream from the A 1065 road bridge (NGR TF91293 29667, August 2010)

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Plate 8 - Reach 27: River Wensum looking towards Hempton meander loop which was reconnected in 2003 (NGR TF90964 29611)

Plate 9 - Reach 27 – Installed gravel glide with aquatic plant assemblage

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Plate 10 - Reach 27: River Wensum upstream of reconnected meander loop (looking u/s) showing natural vegetation and berm encroachment

Plate 11 – Reach 27: River Wensum flowing confined within high embanked section. Embankments contain high proportion of gravels indicating spoil generated from historic instream dredging (NGR TF90347 29721, August 2010)

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Plate 12 – Reach 28: River Wensum exhibiting good gravel habitat at site of self-sown willow (NGR TF89653 30316, August 2010)

Plate 13 -– Reach 28: Location of possible channel realignment to TLHB at Sculthorpe Moor (NGR TF89687 30001, August 2010)

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Plate 14 – Reach 29: River Wensum at old railway crossing, Shereford. River flow negligible, channel significantly over widened with silt bed and abundant instream plant growth (NGR TF88622 29631, August 2010)

Plate 15 – Reach 29: River Wensum downstream of Southmill Farm. Channel is self narrowing through vegetated berm encroachment, free flowing with water starwort and clean gravel. (NGR TF88110 28804, August 2010)

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Plate 16 – Reach 30: River Wensum looking downstream on approach to South Mill. Over wide and deep with marginal plant encroachment and silty bed (NGR TF88080 28223, August 2010)

Plate 17 – Reach 30: River Wensum channel choked with emergent bur reed causing an obstruction to flow (NRG TF87762 28053, August 2010)

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Plate 18 – Reach 31: River Tat at confluence with the River Wensum (NGR TF87573 28036, August 2010)

Plate 19 – Reach 31: River Tat at confluence with the River Wensum (NGR TF87573 28036, August 2010)

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4. Consultation 4.1 Introduction This chapter summarises comments received from key statutory stakeholders and the public. A drop-in session covering this river unit was held at Fakenham Racecourse in September 2009. In addition, one-to-one interviews have been conducted with a number of stakeholders in this unit. 4.2 Consultation with key stakeholders Since 2008, the project team has been communicating with various internal and external stakeholders during the feasibility assessment and the Environment Agency has contacted key staff within different organisations regarding various EIA and planning matters for the River Wensum as a whole. Table 4.1 summarises the responses of these organisations. It should be noted that many of these responses are generic, rather than specific to this particular unit. Table 4.1 - Consultation undertaken to date (August 2010)

Date Nature of Consultation / Consultee Responses Organisation Consulted Statutory Consultees Joint meeting with officers from planning and environment from each council to introduce the restoration strategy, proposals developed for other units and planning and environmental issues. Officers were assured that the KLWNDC and NNDC September 2009 restoration strategy would not increase flood risk to people and property. Officers showed overall interest and support but further consultation would be needed in future, including the need to confirm permitted development rights. The first meeting presented the objectives of the Strategy. The IDB did not disagree with the overall proposals but expressed concern over Environment Agency maintenance on the main river. Norfolk Rivers IDB / September 2008 The second meeting discussed a number of potential joined Water Management and May 2009 up approaches to targeted river maintenance. This Alliance collaborative approach would see a shift to river maintenance practices which are likely to benefit both river restoration and angling interests whilst addressing some of the key landowner concerns. A reply was received in April 2009. The landscape team Norfolk County would like further EIA assessment to make a more detailed March 2009 Council – Landscape appraisal of potential impacts (good and bad) to the landscape character and visual amenity of the River Wensum. Key staff were briefed on the proposal, including the issue of winning gravels from site or from an external source e.g. Norfolk County existing gravel pit site. Council provided their “in principle” November 2008 Council – Minerals support for restoration and indicated that if gravels had to be brought to site from elsewhere then planning permission may be required. Internal meeting held in November 2008 to raise awareness of project and to identify issues of implementation. The Development and Flood Risk Team has confirmed that a Internal Environment Flood Risk Assessment will be required. The Flood Risk November 2008 Agency Functions Assessment will have to show: 1) Any changes in the extent of floodplain. 2) Any changes in depth of flooding. 3) Likely impact on any properties. Recognises the need to implement a recommended option to Natural England 2008 deliver ‘favourable’ condition to the SSSI.

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Date Nature of Consultation / Consultee Responses Organisation Consulted

The Initiative is a partnership between Defra, Natural England England Catchment and the Environment Agency. Ongoing consultations with Sensitive Farming April 2008 local Catchment Sensitive Farming Officer, to identify specific Delivery Initiative diffuse pollution from agriculture problems. Non-Statutory Consultees Landowners August 2010 The project team met with the Hawk and Owl Trust at Sculthorpe Moor Community Nature Reserve to discuss options for restoration along land they manage. Potential conflicts between river restoration and current management practices at the reserve (e.g. need to protect habitats dependent on high quality groundwater from inundation by river water), and opportunities for channel realignment, were discussed. This was a joint presentation with a representative from the England Catchment Sensitive Farming Delivery Initiative Broads Forum October 2008 highlighting the benefits of reducing sediment input into the Wensum. Another key message was the need to prevent silt ingress into river reaches downstream of restoration sites. Presentation was given to the Steering Group which focused on the benefits of re-establishing the hydrological relationship Norfolk Biodiversity January 2007 between river and floodplain and the potential benefits to BAP Partnership habitat. The Group was enthusiastic, but as a policy they do not express support for specific projects. The meeting focused on understanding their objectives for the Wensum Valley Trust July 2008 Wensum Valley, particularly in relation to river restoration. Norfolk Anglers The presentation focused on the synergy between river Conservation May 2008 restoration and benefits for fisheries. Support was expressed Association for implementation of the Strategy. April 2008 The meeting was intended to bring the National Farmers Union up to speed with the development of the Strategy and to give them an understanding of what we are trying to achieve. National Farmers

Union January 2011 Project staff attended an NFU organised meeting to discuss progress with a number of Wensum issues, including diffuse pollution, access on the river, river restoration and water resources. Waterbodies BAP The Group expressed a general support for the October 2007 Topic Group implementation of the Strategy. River Restoration Presentation focused on how the Strategy was developed, the Centre Annual April 2007 issues that it will address and how we intend to take it Network Conference forward.

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4.3 Drop-in session September 2009 A drop-in session about the implementation of the River Wensum Restoration Strategy between Tatterford Common and Fakenham Mill was held on 8th September 2009 at Fakenham Racecourse. The objectives of the session were:  To engage with people who live within the vicinity of this part of the river, and are likely to be affected by the proposed restoration works.  To identify the key environmental concerns / constraints and opportunities with respect to strategic options available for implementing river restoration between Tatterford Common and Fakenham Mill.  To gain an insight into local knowledge of the river.  To help identify acceptable options, that are environmentally, technically and economically feasible, to deliver ‘unfavourable recovering’ or ‘favourable’ ecological condition. The drop-in was designed to ensure that the local landowners, parish councillors and interested stakeholders had an opportunity to comment and present their views on river restoration specific to Unit 47. A total of 64 people attended the drop-in session. Attendees recognised that there has been a general decline in the river’s condition, particularly its ecological character and many agreed that the river is in need of some work to improve its condition. Comments recorded on the feedback forms completed by attendees related to:  Positive response to the fact that time and money is being invested in the river’s future.  The failure to instigate a planned maintenance system.  The lack of regular dredging.  Concerns about increasing flood risk.  How compatible new restoration measures will be on existing structures, such as the mills, which are of importance for local heritage and landscape character.  The financial costs of the proposed measures.  The need to explore the possibilities of utilising mill structures to generate electricity and the compatibility of hydropower schemes with river restoration.  The lack of public access to the river, in particular where restoration is proposed. Many attendees were not convinced by the restoration measures presented and requested that they are consulted when further details are available. Particular concerns related to necessity and the economic justification for restoration measures. 4.4 Future consultation Some specific constraints and opportunities identified following the Atkins site visits on this unit are considered below, and include, but are not limited to: Constraints:  Accessibility: There may be a limit as to the number and type of restoration works proposed for this part of the river given the lack of access and ground conditions in some reaches including the presence of riparian sections especially in reaches 27 and 28.  Ecology: The environmental impact of improving habitats for some flora and fauna could be detrimental for others.

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 Need to protect sensitive groundwater fed vegetation communities at Sculthorpe Moor from inundation with river water. Opportunities:  Ecology: Site won materials can be used to create and improve in-stream conditions. This includes felling of trees to be used as large woody debris.  Ecology: Enhanced connectivity between main channel and IDB drains will improve the availability of spawning habitat, potentially increasing fish recruitment.  Land-use: Low flood risk to people and property along much of the unit provides opportunities for large-scale river restoration and restoring floodplain connectivity.  Opportunity to combine river restoration with storage of floodwater on floodplain upstream of Fakenham. An Environmental Report, outlining the key management actions that would be taken to reduce the potential impacts to the environment as a result of the recommended river restoration option(s), will be produced in parallel with the detail design. Further consultation with local landowners and internal and external stakeholders will be undertaken as part of this process.

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5. Multi-Criteria Analysis Options Appraisal 5.1 Introduction A Multi-Criteria Analysis (MCA) system, based on weighted numerical scoring, has been used to help select appropriate restoration options / measures for each river reach. This was considered necessary to ensure that a transparent, defendable and replicable technique of selecting options / measures was applied. This chapter describes the process by which the MCA tool was designed and subsequently applied. A number of options have been considered which could be implemented individually, or as a group, to restore ‘unfavourable recovering’ or ‘favourable’ condition to the River Wensum. The chapter concludes by presenting the most favourable scoring options / measures for the study reaches. Costs have been excluded from this MCA process and are considered subsequently in Chapter 7. Further details of the MCA process (MCA technical note and MCA table) can be found in Appendix A to this report. Table 5.1 provides an overview of the steps involved in constructing and applying the MCA tool, and Section 5.2 provides more detail. Table 5.1 - Overview of the process by which the MCA was constructed and applied A Constructing the MCA Tool 1 Identification of options / measures

2 Selection of success criteria 3 Ranking of success criteria 4 Setting up the MCA table B Applying the MCA Tool (Spreadsheet) to Specific Reaches 1 Is the option / measure applicable to the reach? If no, discard. 2 Work through each criterion by option / measure. 3 Apply weighting and determine total weighted score (TWS) 4 Mill structure measures: Apply the best scoring measure. Other measures: Undertake statistical analysis and discard measures scoring 5 below lower limit.

Other measures: Apply remaining measures in order of highest to lowest 6 scoring. 7 Gravel works: Apply best scoring measure.

5.2 Constructing the MCA tool The MCA Table provides the framework for the options appraisal process, and scores the degree to which all the proposed restoration options / measures meet the defined criteria. The initial stage in the options appraisal was the construction of the Table, which involved defining the options / measures to be considered, and defining the criteria against which the options / measures are evaluated. Following the construction of the Table, it was applied as a tool to determine the highest scoring options / measures for each reach.

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5.2.1 Identification of options / measures A generic list of all restoration options / measures possibly applicable to the River Wensum was generated through the following activities:  Document review: All options and restoration measures recommended in the RWRS and the Geomorphological Appraisal were considered and all were included in the final list of options. Table 5.2 lists the measures recommended in these two reports. Table 5.2 - Restoration measures recommended in previous studies Reach Geomorphological Appraisal River Wensum Restoration Strategy All works to integrate with lowering of structure Fix sediment ingress points. Remove at Fakenham Mill and associated river works. fine sediments. Reduce water levels by Must also integrate with proposed flood risk lowering levels at Fakenham Mill. Re- management capital project and link with 26 use dredged materials to restore bed existing enhancements. De-silt channel just elevation and reduce channel width. upstream of Fakenham Mill, physically narrow Use woody debris structures to enhance and augment bed with gravels. Encourage instream habitat. development of marginal / bankside vegetation.

Fix sediment ingress points. Remove All works to integrate with lowering of structure fine sediments. Reduce water levels by at Fakenham Mill and associated river works lowering levels at Fakenham Mill. Re- and must link with the existing enhancement 27 use dredged materials to restore bed schemes. Physically narrow and augment bed elevation and reduce channel width. with gravels and develop marginal / bankside Use woody debris structures to enhance vegetation. Remove embankments to instream habitat. reconnect river to its floodplain.

Use woody debris structures to create Use coarse woody debris structures to scour pools and enhance instream exacerbate sinuosity in the wooded area where habitat. Fix sediment ingress points. channel is straight. Remove embankments to Remove fine sediments. Reduce water reconnect river to its floodplain and augment 28 levels by lowering levels at Fakenham bed with gravel. Develop marginal / bankside Mill. Re-use dredged materials to vegetation to encourage channel to narrow restore bed elevation and reduce naturally. Potential to use wood from poplar channel width. plantations.

Fix sediment ingress points. Dredge silts All works to integrate with lowering of structure from ponded reaches. Look at options at Sculthorpe Mill and associated river works. for reducing the level of the mill weir as De-silt channel just upstream of Sculthorpe Mill, this provides benefits for upstream physically narrow and augment bed with 29 channel gradients and dimensions. Look gravels. Remove scrub to open up the channel at options for restoration of gravel bed if and encourage development of marginal / height of mill weir is reduced. Dredge bankside vegetation. Use coarse woody debris silts from channel prior to removal or structures to exacerbate sinuosity in the reduction in height of mill. wooded area where channel is straight.

All works must integrate with removal of sill- type structure at South Mill and any associated river works. Reinstate meandering channel with appropriate sinuosity and fill in the existing channel that was created as a diversion when South Mill was in use. The original channel is Fix sediment ingress point. Re-establish not evident on the floodplain, although a drain a smaller, higher level meandering seen on the OS map along the left bank of the 30 channel. Use spoil to partially infill former Wensum may represent a previous river course. course. Further, as there are no suitable reference reaches at this location in the catchment, restoration channel dimensions should be based on hydraulic geometry calculations. It would be suitable to reconnect the restoration channel with the existing channel at the road bridge by South Mill. Develop marginal / bankside vegetation, with

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Reach Geomorphological Appraisal River Wensum Restoration Strategy some riparian trees. Connect to drains or create off-river refuges.

Encourage less extensive stocking of livestock and develop marginal / bankside vegetation. Establish monitoring programme. 31 Allow to narrow naturally. Remove Cessation of maintenance regime. embankments to reconnect the river to its floodplain.

Consultation: This took the form of a public drop-in session, as described in Chapter 4 of this report. Consultation with authorities such as North Norfolk District Council and King’s Lynn and West Norfolk District Council was also undertaken. Workshop: An MCA workshop, attended by the Environment Agency, Natural England and Atkins, was held on 29th January 2009 with the purpose of working through the MCA approach. From the above sources, six main option groups were identified namely ‘Do nothing’, ‘Do minimum’, ‘Targeted maintenance’, ‘Continue as present’, ‘River restoration ’ and ‘Alternative options’. These are explained in Table 5.3. Appendix A provides further information regarding the options. Table 5.3 - Options identified for restoration on the River Wensum

No. Option Description No maintenance to main river or IDB channels. No restoration to G1 Do nothing any channels or floodplain. No operational activities such as weed cutting. No maintenance to main river or IDB channels. Opportunistic restoration in certain areas (e.g. trees may be felled where G2 Do minimum appropriate thereby reducing channel shading). No operational activities such as weed cutting. Reduced maintenance to include only reactive activities e.g. removal of debris posing an immediate flood risk or removal of silt G3 Targeted maintenance in specific locations. Mitigation for activity in the form of small scale restoration. Limited operational activities e.g. sluice management for high flows. Continuation of existing activities which includes maintenance (debris removal, bank repairs, selected desilting and selected weed G4 Continue as present cutting). Undertaking small scale, opportunistic restoration activities. Continuation of operational activities such as sluice management during high flows. Active restoration measures of which 21 such measures have been identified and grouped into three sub-groups namely ‘Mill G5 River restoration structures’, ‘Gravel works’ and ‘Other’. See Appendix A for a full list of these measures. Three options have been considered within this group, namely ’Increasing main river maintenance’, ‘Increased main river and IDB G6 Alternative options maintenance’, and ‘Mills re-used for hydro-power’. These are explained further in Appendix A.

Three groups of ’measures’ have been defined under the option G5 (see Table 5.4 for full details). These include:  Various works around mill structures including changes to operating protocol, lowering mill sill levels and constructing / utilising existing bypass channels.  Various gravel works including large scale bed raising.  Other measures.

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Table 5.4 - Description of river restoration measures as defined under option G5 Group Restoration Measure Description Modify existing mill operating protocols to ensure Improve operation water level management is in line with SSSI protocols management. Mill Structure Works Remove flow control Remove all sluice control mechanisms and allow These works mechanisms the river to be free flowing. Lower the level of the mill sill to reduce the extent need to be Lower mill sill levels undertaken first of backwater in low flows. Construction of channel around mill to split flows to ensure the Create bypass channel to allow fish passage and continuity of stream success of any around mill subsequent processes. Construction of fish pass alongside mill structure measures Install fish pass to enable free passage of fish upstream. Remove mill structure Remove entire mill structure. Creation of short lengths of full width raised bed, Gravel Works Gravel glides dressed in gravel, to create variation in flow and Need to be habitat for fish and invertebrates. considered (and Creation of short lengths of raised gravel bed with constructed) Gravel glides and hurdles made from post and faggots to trap after Mill transverse hurdles suspended sediment thereby extending the Structure Works length of the glide over time. have been Creation of extended lengths of full width raised completed Bed raising bed – to reduce water depth and allow characteristic plant communities to develop. Fencing constructed landward of the river bank to Fencing prevent bank erosion from the impacts of cattle grazing. Tree planting to cast shade over the water to control macrophyte growth, provide cover for fish, Tree planting and to develop erosion resistance from root reinforcement. Selective felling or lopping to provide light onto Tree thinning the water to encourage macrophyte or emergent plant growth, and generate arisings for deflectors. Other Deflector (using Large Downstream pointing LWD placed at the Measures Woody Debris (LWD) upstream side of deflector to create flow diversity;

and filled in with brush in-filled downstream with brush to promote silt These need to mattress) deposition and plant growth. be considered Removal of dredging based informal after Mill Lower spoil embankments to allow out of bank flow across Structure embankments the floodplain, and back into the river. Use of Works and arisings for riffles / general bed raising if needed. Gravel Works Horizontal lowering of bank top up to 1/2 channel have been width to increase flood flow capacity and identified Berm creation generate arisings for bed raising where no

embankments. Backchannels – Utilizing existing wet features by connecting them reconnections to IDB to the river to create essential habitat for fish and and existing field drains other fauna. Creating habitat where no other water bodies Backchannels – create exist e.g. dog-leg with downstream end open and new features upstream end fed by percolation. Full depth excavation from bank top to increase Channel realignment to lateral variation in plan form either one bank or increase river sinuosity both with arisings used to infill opposite bank.

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5.2.2 Selection of success criteria ‘Criteria’ refer to the various standards against which the proposed options / measures are evaluated. A range of criteria (12 in total) were defined during a workshop between Atkins, Environment Agency and Natural England in January 2009. These criteria have been grouped under the following three broad headings: 1. Ecology: This includes criteria relating to legally protected ecology, such as compliance with the SSSI designation, as well as that which is not legally protected, but where the proponents of the works still have a responsibility to safeguard and improve ecological value of the site. Three of the criteria within this group relate to three levels of legal designations, and the final criterion covers all non-legal responsibilities.

2. Project delivery: This considers compliance with the objectives of the RWRS and takes into account stakeholder opinion. Hence compliance/agreement with requirements of statutory and non-statutory stakeholders is considered.

3. Technical: This group considers delivery of the technical aspects of the RWRS objectives including technical feasibility, geomorphic form, flood risk and climate change.

All criteria and accompanying descriptions are provided in Table 5.5. 5.2.3 Ranking success criteria While all of the defined criteria groups are significant, it is acknowledged that some are more so than others. For example, ecology is the main driver of the project and the primary objective is to improve the ecology of the River Wensum. Hence, compliance with these criteria can be considered as more important than, for example, technical considerations and hence a weighting system has been applied to these groups. Similarly, different criteria within a single group such as ‘Ecology’ are not necessarily of equal importance. For example, the criterion ‘Compliance with National Designation’ (such as SSSI), which falls within the ‘Ecology’ group, is the main driver for this project, and hence compliance with this criterion is considered essential for achieving project objectives. The criterion ‘Contribution to overall ecology’ would be considered less important. Hence, a similar weighting system has been applied to individual criteria within the three groups. Professional judgement was applied in determining the numerical weighting for each criteria group and each criterion. A weighted score between zero and one was applied and agreed to in the MCA workshop. An ‘effective weighting factor’ for each criterion was calculated by multiplying the group criteria weighting and the individual criteria weighting. Table 5.5 presents the criteria and applied weightings and Appendix A provides a detailed explanation for the weighting of criteria.

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Table 5.5 - Criteria defined for the MCA

Group Weighting Effective (group Criterion Description / Example Within Weighting weighting) Group Factor SSSI requirements for the Compliance with river e.g. improved flow 1 1 national designation regime, water quality and channel form. SAC requirements Compliance with including maintaining international 0.8 0.8 favourable habitat for EU designation Ecology designated species. (1) BAP requirements such as Compliance with maintaining flora and fauna regional / local 0.6 0.6 characteristic of chalk designations rivers. Compliance with the Contribution to Environment Agency’s 0.5 0.5 overall ecology general duty to further conservation Meeting objectives of the Compliance with RWRS as well as the strategy (RWRS) 1 0.9 specific reach objectives recommendations. Stakeholders include Environment Agency, Compliance with Natural England, North statutory 0.9 0.81 Project Norfolk District Council, stakeholders delivery and Norfolk County (0.9) Council. Agreement with non- Angling clubs, land owners statutory 0.9 0.81 and tenants. stakeholders Consideration of or improvements to Human environment 0.4 0.36 archaeology, landscape, and recreation value. Consideration of design, Technical feasibility & construction process, 1 0.8 practicality commercial risk, and maintenance. Geomorphic form Consideration of the shape 1 0.8 Technical and function and flow of the river. (0.8) Consideration of the impact Flood risk 1 0.8 of restoration on flood risk. Considers the robustness Climate change and of the measures in terms of 0.8 0.64 sustainability future flood risk and carbon footprint.

5.2.4 Setting up the MCA Table Defining the scoring system The MCA Table lists all of the options / measures against the 12 defined criteria and a score is allocated depending on the degree to which the individual options / measures comply with the criteria.

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The term ‘relevance’ is used to describe where a particular option / measure complies with the criteria or brings about betterment of the features pertaining to those criteria. The term ‘detriment’ is used where a particular option / measure does not comply with the criteria or results in an adverse change to a particular feature pertaining to those criteria. A five point scoring system is utilised with +2 allocated if the option / measure is of high relevance and -2 allocated where the option / measure is of high detriment. These terms are presented in Table 5.6. Table 5.6 - Scoring system defined for the Multi-Criteria Analysis

Score Description +2 High relevance +1 Low relevance 0 Neutral

-1 Low detriment -2 High detriment

These are applied as ‘raw scores’. From here, a ‘weighted score’ is derived by multiplying the ‘raw score’ by the ‘effective weighting factor’. A ‘total weighted score’ for an individual option / measure is derived by summing all of the ‘weighted scores’ for that option / measure. The consideration of costs was deliberately excluded from the MCA analysis so as not to discriminate against any options or measures, and so determine the best technical solution irrespective of cost. 5.3 Using the MCA tool The MCA tool has been applied to each of the reaches separately on a reach-by-reach basis. The following main steps were undertaken:  The applicability of the option / measure was considered. Where the option / measure is not applicable (e.g. ‘Changing primary and secondary channels’ may not be applicable if no secondary channel exists) then this option / measure has been discarded.  The remaining criteria were then worked through for one option / measure at a time and raw scores allocated. Working through by option / measure allowed greatest consistency of scoring.  Weightings were applied to the raw scores to generate weighted scores.  Total weighted scores (TWS) were calculated for each option / measure by summing all of the weighted scores.  Statistical analysis was applied to the scores within the ‘River Restoration’ (G5) options category. Those scoring below a defined statistically lower limit were discarded. A suffix of “H” to the measure rank indicates a highly important measure; a suffix of L indicates a low importance measure. Appendix A provides further information on the statistical methods.  The measures with the highest TWS represent the preferred suite of options and associated measures for that specific reach. These were applied, in their scored order, for designing a preferred restoration plan for the reach. The results of the MCA analysis for Reaches 26 to 31 are displayed in Tables 5.7 to 5.12 respectively.

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Table 5.7 - Results of MCA for Reach 26 (Fakenham Reach)

River Wensum Multi Criteria Analysis River 47 Criteria Group Ecology [A] Project Delivery [B] Technical [C] Unit: Wensum Group weighting 1 0.9 0.8 Reach: 26 Fakenham Individual weighting within group 0.8 1 0.6 0.5 1 0.9 0.9 0.4 1 1 1 0.8 Length: 464m Criteria Option / Compliance Compliance Compliance Contribution Compliance Compliance Agreement Human Technical Geomorphic Flood Risk Climate Total Total Rank or de r measure with with with to overall with Strategy with with Environment: Feasibility form & [C.c] Change & Raw weighted applicable to International National Regional/Local ecology [A.d] objectives Statutory Non‐statutory Archaeology; & function [C.b] sustainability Score score reach Designation Designation designation (Wildlife & Stakeholders Stakeholders landscape; practicality [C.d] (highest (SAC) [A.a] (SSSI) [A.b] (BAP) [A.c] Fisheries & (EA; NE; BDC; (NACA; recreation [C.a] possible River Form & NCC) [B.b] owners; [B.d] score 24) Process) [B.a] occupiers) [B.c] Individual w eighting factor = 0.8 1 0.6 0.5 0.9 0.81 0.81 0.36 0.8 0.8 0.8 0.64 Option No. Option / measure G1: Do Nothing: No maintenance or restoration: raw score Y ‐2 ‐1 ‐100‐1 ‐2 ‐121‐2 ‐1 ‐8 Weighted score ‐1.6 ‐1 ‐0.6 0 0 ‐0.81 ‐1.62 ‐0.36 1.6 0.8 ‐1.6 ‐0.64 ‐5.83 G2: Do M inim um : minimal restoration: raw score Y ‐1 ‐10010‐1011‐10‐1 Weighted score ‐0.8 ‐10 00.90‐0.81 0 0.8 0.8 ‐0.8 0 ‐0.91 G3: Targeted Maintenance: Raw score Y 0 0112111111111 Weighted score 0 0 0.6 0.5 1.8 0.81 0.81 0.36 0.8 0.8 0.8 0.64 7.92 3 G4: Continue as present: raw score Y ‐1 ‐2 ‐1 ‐2 ‐1 ‐1 ‐102‐11 0‐7 Weighted score ‐0.8 ‐2 ‐0.6 ‐1 ‐0.9 ‐0.81 ‐0.81 0 1.6 ‐0.8 0.8 0 ‐5.32 G5: River Restoration G5a M ill Structures: 5.1m Mill structures - improve operability + protocols: raw score Y 1 101210020019 w eighted score 0.8 1 0 0.5 1.8 0.81 0 0 1.6 0 0 0.64 7.15 5 5.2m Mill structures - remove flow control mechanisms: raw score Y 1 1112‐1 ‐1111119 w eighted score 0.8 1 0.6 0.5 1.8 ‐0.81 ‐0.81 0.36 0.8 0.8 0.8 0.64 6.48 5.3m Mill structures - low er mill sills levels Y 2 2222‐2 ‐2 ‐1 ‐22 2 18 Weighted Score 1.6 2 1.2 1 1.8 ‐1.62 ‐1.62 ‐0.36 ‐1.6 1.6 1.6 0.64 6.24 Mill structures – bypass channels (flow into IDB drain) N 5.4m 0 Weighted Score 0 00000000000 0 5.5m Fish passes Y 0 0120111‐20‐114 Weighted Score 0 0 0.6 1 0 0.81 0.81 0.36 ‐1.6 0 ‐0.8 0.64 1.82 5.6m Mill structures - remove all N 0 Weighted Score 0 00000000000 0 G5b Gravel works: 5.7g Gravel glides Y 2 2122111120217 w eighted score 1.6 2 0.6 1 1.8 0.81 0.81 0.36 0.8 1.6 0 1.28 12.66 1 H 5.8g Gravel glides + transverse hurdles: raw score N 0 w eighted score 0 00000000000 0 5.9g Bed raising (large scale) Y 1 1112100‐11‐117 Weighted Score 0.8 1 0.6 0.5 1.8 0.81 0 0 ‐0.8 0.8 ‐0.8 0.64 5.35 G5c Other: 5.10 Fencing: Raw Score N 0 Weighted Score 0 00000000000 0 5.11 Tree planting on top of bank: raw score Y 0 112011020019 Weighted score 0 1 0.6 1 0 0.81 0.81 0 1.6 0 0 0.64 6.46 7 5.12 Tree thinning: raw score Y 0 1121201101111 w eighted score 0 1 0.6 1 0.9 1.62 0 0.36 0.8 0 0.8 0.64 7.72 4 5.13 Deflector (using LWD and filled in w ith brush mattress) Y 1 112111012‐209 w eighted score 0.8 1 0.6 1 0.9 0.81 0.81 0 0.8 1.6 ‐1.6 0 6.72 6 5.14 Low er spoil embankments N 0 w eighted score 0 00000000000 0 5.15 Channel Re-sectioning N 0 w eighted score 0 00000000000 0 5.16 Berm creation w here appropriate Y 1 112211212‐1013 w eighted score 0.8 1 0.6 1 1.8 0.81 0.81 0.72 0.8 1.6 ‐0.8 0 9.14 2 Backw aters – reconnections to IDB, field drains N 5.17 0 w eighted score 0 00000000000 0 5.18 Backw aters - new N 0 w eighted score 0 00000000000 0 5.19 Channel realignment N 0 w eighted score 0 00000000000 0 5.20 Changing primary and secondary channels (e.g. Ryburgh) N 0 w eighted score 0 00000000000 0 5.21 Low er embankments N 0 Weighted Score 0 00000000000 0

G6: Alternative Options 6.1 Increase Main river maintenance: raw score Y ‐2 ‐1 ‐1 ‐2 ‐1 ‐22 10‐22‐1 ‐7 Weighted score ‐1.6 ‐1 ‐0.6 ‐1 ‐0.9 ‐1.62 1.62 0.36 0 ‐1.6 1.6 ‐0.64 ‐5.38 6.2 Increase main river & IDB channel maintenance: raw score Y ‐2 ‐1 ‐2 ‐2 ‐1 ‐22 01‐11‐1 ‐8 Weighted score ‐1.6 ‐1 ‐1.2 ‐1 ‐0.9 ‐1.62 1.62 0 0.8 ‐0.8 0.8 ‐0.64 ‐5.54 6.3 Mill Structures - reinstatement & maintenance + hydropow er Y ‐2 ‐2 ‐2 ‐2 ‐2 ‐220‐1 ‐2 ‐1 ‐2 ‐16 Weighted Score ‐1.6 ‐2 ‐1.2 ‐1 ‐1.8 ‐1.62 1.62 0 ‐0.8 ‐1.6 ‐0.8 ‐1.28 ‐12.08 Total Score 0.2 7 7.4 15 22.8 ‐0.81 11.05 9.16 16 11.6 2 9.2 Key Score Description Mean: 7.22 2High Relevance SD: 2.23 1Low Relevance 0Neutral High imp: >9.45 ‐1Low Detriment Low imp: <4.99 ‐2High Detriment

Unit 47 Tatterford Common to Fakenham Mill_Final.docx 73 River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Table 5.8 - Results of MCA for Reach 27 (Hempton Reach)

River Wensum Multi Criteria Analysis River 47 Criteria Group Ecology [A] Project Delivery [B] Technical [C] Unit: Wensum Group weighting 1 0.9 0.8 Reach: 27 Hempton Individual weighting within group 0.8 1 0.6 0.5 1 0.9 0.9 0.4 1 1 1 0.8 Length: 1720m Criteria Option / measure Compliance with Compliance with Compliance with Contribution to Compliance with Compliance with Agreement with Human Technical Geomorphic Flood Risk Climate Total Raw Total Rank order applicable to reach International National Regional/Local overall ecology Strategy Statutory Non‐statutory Environment: Feasibility & form & function [C.c] Change & Score weighted Designation (SAC) Designation (SSSI) designation (BAP) [A.d] objectives Stakeholders Stakeholders Archaeology; practicality [C.b] sustainability (highest score [A.a] [A.b] [A.c] (Wildlife & (EA; NE; BDC; (anglers; owners; landscape; [C.a] [C.d] possible Fisheries & River NCC) [B.b] occupiers) [B.c] recreation [B.d] score 24) Form & Process) [B.a]

Individual weighting factor = 0.8 1 0.6 0.5 0.9 0.81 0.81 0.36 0.8 0.8 0.8 0.64 Option No. Option / measure G1: Do Nothing: No maintenance or restoration: raw score Y ‐2 ‐1 ‐10 0‐1 ‐2 ‐221‐1 ‐1 ‐8 Weighted score ‐1.6 ‐1 ‐0.6 0 0 ‐0.81 ‐1.62 ‐0.72 1.6 0.8 ‐0.8 ‐0.64 ‐5.39 G2: Do Minimum: minimal restoration: raw score Y ‐1 ‐10010‐1011000 Weighted score ‐0.8 ‐10 00.90‐0.81 0 0.8 0.8 0 0 ‐0.11 G3: Targeted Maintenance: raw score Y 0 0112121110111 Weighted score 0 0 0.6 0.5 1.8 0.81 1.62 0.36 0.8 0.8 0 0.64 7.93 7 G4: Continue as present: raw score Y ‐1 ‐2 ‐1 ‐2 ‐1 ‐1 ‐102‐10 0‐8 Weighted score ‐0.8 ‐2 ‐0.6 ‐1 ‐0.9 ‐0.81 ‐0.81 0 1.6 ‐0.8 0 0 ‐6.12 G5: River Restoration G5a Mill Structures: 5.1m Mill structures - improve operability + protocols: raw score Y 1 101120020008 weighted score 0.8 1 0 0.5 0.9 1.62 0 0 1.6 0 0 0 6.42 10 5.2m Mill structures - remove flow control mechanisms: raw score Y 1 1011‐1 ‐1111106 weighted score 0.8 1 0 0.5 0.9 ‐0.81 ‐0.81 0.36 0.8 0.8 0.8 0 4.34 5.3m Mill structures - lower mill sills levels Y 1 1122‐20‐1 ‐21 1 04 Weighted Score 0.8 1 0.6 1 1.8 ‐1.62 0 ‐0.36 ‐1.6 0.8 0.8 0 3.22 5.4m Mill structures – bypass channels (flow into IDB drain) N 0 Weighted Score 0 00000000000 0 5.5m Fish passes Y 0 1110111‐20 0 15 Weighted Score 0 1 0.6 0.5 0 0.81 0.81 0.36 ‐1.6 0 0 0.64 3.12 5.6m Mill structures - remove all N 0 Weighted Score 0 00000000000 0 G5b Gravel works: 5.7g Gravel glides Y 2 2122111220218 weighted score 1.6 2 0.6 1 1.8 0.81 0.81 0.36 1.6 1.6 0 1.28 13.46 1 H 5.8g Gravel glides + transverse hurdles: raw score N 0 weighted score 0 00000000000 0 5.9g Bed raising (large scale) Y 1 111211011‐1110 Weighted Score 0.8 1 0.6 0.5 1.8 0.81 0.81 0 0.8 0.8 ‐0.8 0.64 7.76 G5c Other: 5.10 Fencing: Raw Score Y 0 00110‐1 ‐1200 02 Weighted Score 0000.50.90‐0.81 ‐0.36 1.6 0 0 0 1.83 13 L 5.11 Tree planting on top of bank: raw score Y 0 101011220019 Weighted score 0 1 0 0.5 0 0.81 0.81 0.72 1.6 0 0 0.64 6.08 12 5.12 Tree thinning: raw score Y 1 1111211200112 weighted score 0.8 1 0.6 0.5 0.9 1.62 0.81 0.36 1.6 0 0 0.64 8.83 5 5.13 Deflector (using LWD and filled in with brush mattress) Y 1 2111210120113 weighted score 0.8 2 0.6 0.5 0.9 1.62 0.81 0 0.8 1.6 0 0.64 10.27 3 5.14 Lower spoil embankments Y 0 11122‐11111111 weighted score 010.60.51.81.62‐0.81 0.36 0.8 0.8 0.8 0.64 8.11 6 5.15 Channel Re-sectioning Y 1 2111211121216 weighted score 0.8 2 0.6 0.5 0.9 1.62 0.81 0.36 0.8 1.6 0.8 1.28 12.07 2 H 5.16 Berm creation where appropriate Y 1 2111111120113 weighted score 0.8 2 0.6 0.5 0.9 0.81 0.81 0.36 0.8 1.6 0 0.64 9.82 4 5.17 Backwaters – reconnections to IDB, field drains Y 0 11201‐11210210 weighted score 010.6100.81‐0.81 0.36 1.6 0.8 0 1.28 6.64 9 5.18 Backwaters - new Y 0 111011111019 weighted score 0 1 0.6 0.5 0 0.81 0.81 0.36 0.8 0.8 0 0.64 6.32 11 5.19 Channel realignment Y 1 21202‐21‐12 0 210 weighted score 0.8 2 0.6 1 0 1.62 ‐1.62 0.36 ‐0.8 1.6 0 1.28 6.84 8 5.20 Changing primary and secondary channels (e.g. Ryburgh) N 0 weighted score 0 00000000000 0 5.21 Lower embankments N 0 Weighted Score 0 00000000000 0

G6: Alternative Options 6.1 Increase Main river maintenance: raw score Y ‐2 ‐2 ‐2 ‐2 ‐2 ‐21 10‐21‐2 ‐13 Weighted score ‐1.6 ‐2 ‐1.2 ‐1 ‐1.8 ‐1.62 0.81 0.36 0 ‐1.6 0.8 ‐1.28 ‐10.13 6.2 Increase main river & IDB channel maintenance: raw score Y ‐2 ‐2 ‐2 ‐2 ‐2 ‐21 01‐21‐2 ‐13 Weighted score ‐1.6 ‐2 ‐1.2 ‐1 ‐1.8 ‐1.62 0.81 0 0.8 ‐1.6 0.8 ‐1.28 ‐9.69 6.3 Mill Structures - reinstatement & maintenance + hydropower Y ‐2 ‐2 ‐1 ‐1 ‐2 ‐2 ‐10‐1 ‐1 ‐1 ‐2 ‐16 Weighted Score ‐1.6 ‐2 ‐0.6 ‐0.5 ‐1.8 ‐1.62 ‐0.81 0 ‐0.8 ‐0.8 ‐0.8 ‐1.28 ‐12.61 Total Score 3.8 21 10.6 21 20.9 17.29 5.62 15.6 34 22.4 6.4 17.4 Key Score Description Mean: 8.05 2 High Relevance SD: 2.97 1 Low Relevance 0Neutral High imp: >11.01 ‐1Low Detriment Low imp: <5.08 ‐2High Detriment

Unit 47 Tatterford Common to Fakenham Mill_Final.docx 74 River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Table 5.9 - Results of MCA for Reach 28 (Moor Reach)

River Wensum Multi Criteria Analysis River 47 Criteria Group Ecology [A] Project Delivery [B] Technical [C] Unit: Wensum Group weighting 10.90.8Reach: 28 Moor Individual weighting within group 0.8 1 0.6 0.5 1 0.9 0.9 0.4 1 1 1 0.8 Length: 1245m Criteria Option / measure Compliance with Compliance with Compliance with Contribution to Compliance with Compliance with Agreement with Human Technical Geomorphic Flood Risk Climate Total Raw Total Rank order applicable to reach International National Regional/Local overall ecology Strategy Statutory Non‐statutory Environment: Feasibility & form & function [C.c] Change & Score weighted Designation (SAC) Designation (SSSI) designation (BAP) [A.d] objectives Stakeholders Stakeholders Archaeology; practicality [C.b] sustainability (highest score [A.a] [A.b] [A.c] (Wildlife & (EA; NE; BDC; (NACA; owners; landscape; [C.a] [C.d] possible Fisheries & River NCC) [B.b] occupiers) [B.c] recreation [B.d] score 24) Form & Process) [B.a]

Individual weighting factor = 0.8 1 0.6 0.5 0.9 0.81 0.81 0.36 0.8 0.8 0.8 0.64 Option No. Option / measure G1: Do Nothing: No maintenance or restoration: raw score Y ‐1 0010‐1 ‐1 ‐120‐1 ‐1 ‐3 Weighted score ‐0.8 0 0 0.5 0 ‐0.81 ‐0.81 ‐0.36 1.6 0 ‐0.8 ‐0.64 ‐2.12 G2: Do Minimum: minimal restoration: raw score Y 0 01110‐101100 4 Weighted score 000.60.50.90‐0.81 0 0.8 0.8 0 0 2.79 G3: Targeted Maintenance: raw score Y 1 1112120120113 Weighted score 0.8 1 0.6 0.5 1.8 0.81 1.62 0 0.8 1.6 0 0.64 10.17 6 G4: Continue as present: raw score Y ‐1 ‐1 ‐1 ‐1 ‐1 ‐10 12‐11‐1 ‐4 Weighted score ‐0.8 ‐1 ‐0.6 ‐0.5 ‐0.9 ‐0.81 0 0.36 1.6 ‐0.8 0.8 ‐0.64 ‐3.29 G5: River Restoration G5a Mill Structures: 5.1m Mill structures - improve operability + protocols: raw score N 0 weighted score 0 00000000000 0 5.2m Mill structures - remove flow control mechanisms: raw score N 0 weighted score 0 00000000000 0 5.3m Mill structures - lower mill sills levels N 0 Weighted Score 0 00000000000 0 5.4m Mill structures – bypass channels (flow into IDB drain) N 0 Weighted Score 0 00000000000 0 5.5m Fish passes N 0 Weighted Score 0 00000000000 0 5.6m Mill structures - remove all N 0 Weighted Score 0 00000000000 0 G5b Gravel works: 5.7g Gravel glides Y 1 2212222120219 weighted score 0.8 2 1.2 0.5 1.8 1.62 1.62 0.72 0.8 1.6 0 1.28 13.94 1 H 5.8g Gravel glides + transverse hurdles: raw score Y 2 1221111210115 weighted score 1.6 1 1.2 1 0.9 0.81 0.81 0.36 1.6 0.8 0 0.64 10.72 5.9g Bed raising (large scale) Y 1 1112010‐11‐117 Weighted Score 0.8 1 0.6 0.5 1.8 0 0.81 0 ‐0.8 0.8 ‐0.8 0.64 5.35 G5c Other: 5.10 Fencing: Raw Score Y 0 101012021019 Weighted Score 0 1 0 0.5 0 0.81 1.62 0 1.6 0.8 0 0.64 6.97 10 5.11 Tree planting on top of bank: raw score Y 0 101‐111120017 Weighted score 0100.5‐0.9 0.81 0.81 0.36 1.6 0 0 0.64 4.82 12 L 5.12 Tree thinning: raw score Y 1 1121222210015 weighted score 0.8 1 0.6 1 0.9 1.62 1.62 0.72 1.6 0.8 0 0 10.66 4 5.13 Deflector (using LWD and filled in with brush mattress) Y 2 2122110220116 weighted score 1.6 2 0.6 1 1.8 0.81 0.81 0 1.6 1.6 0 0.64 12.46 2 5.14 Lower spoil embankments Y 0 0012221‐11 1 110 weighted score 0 0 0 0.5 1.8 1.62 1.62 0.36 ‐0.8 0.8 0.8 0.64 7.34 9 5.15 Channel Re-sectioning Y 0 1111122110112 weighted score 0 1 0.6 0.5 0.9 0.81 1.62 0.72 0.8 0.8 0 0.64 8.39 8 5.16 Berm creation where appropriate Y 1 2111211220115 weighted score 0.8 2 0.6 0.5 0.9 1.62 0.81 0.36 1.6 1.6 0 0.64 11.43 3 5.17 Backwaters – reconnections to IDB, field drains Y 0 1220220210113 weighted score 0 1 1.2 1 0 1.62 1.62 0 1.6 0.8 0 0.64 9.48 7 5.18 Backwaters - new Y 0 112011011019 weighted score 0 1 0.6 1 0 0.81 0.81 0 0.8 0.8 0 0.64 6.46 11 5.19 Channel realignment Y 1 222‐1122120115 weighted score 0.8 2 1.2 1 ‐0.9 0.81 1.62 0.72 0.8 1.6 0 0.64 10.29 5 5.20 Changing primary and secondary channels (e.g. Ryburgh) N 0 weighted score 00000000000 0 5.21 Lower embankments N 0 Weighted Score 0 00000000000 0

G6: Alternative Options 6.1 Increase Main river maintenance: raw score Y ‐2 ‐2 ‐2 ‐2 ‐2 ‐2 ‐201‐20‐1 ‐16 Weighted score ‐1.6 ‐2 ‐1.2 ‐1 ‐1.8 ‐1.62 ‐1.62 0 0.8 ‐1.6 0 ‐0.64 ‐12.28 6.2 Increase main river & IDB channel maintenance: raw score Y ‐2 ‐2 ‐2 ‐2 ‐2 ‐1 ‐1 ‐11‐21‐2 ‐15 Weighted score ‐1.6 ‐2 ‐1.2 ‐1 ‐1.8 ‐0.81 ‐0.81 ‐0.36 0.8 ‐1.6 0.8 ‐1.28 ‐10.86 6.3 Mill Structures - reinstatement & maintenance + hydropower N 0 Weighted Score 0 00000000000 0 Total Score 8.2 24 17.6 24.5 15.2 24.53 31.77 15.96 41.2 25.2 2.8 15.76 Key Score Description Mean: 9.37 2 High Relevance SD: 3.64 1 Low Relevance 0Neutral High imp: >13 ‐1Low Detriment Low imp: <5.73 ‐2High Detriment

Unit 47 Tatterford Common to Fakenham Mill_Final.docx 75 River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Table 5.10 - Results of MCA for Reach 29 (Shereford Reach)

River Wensum Multi Criteria Analysis River 47 Criteria Group Ecology [A] Project Delivery [B] Technical [C] Unit: Wensum Group weighting 10.90.8Reach: 29 Shereford Individual weighting within group 0.8 1 0.6 0.5 1 0.9 0.9 0.4 1 1 1 0.8 Length: 2630m Criteria Option / measure Compliance with Compliance with Compliance with Contribution to Compliance with Compliance with Agreement with Human Technical Geomorphic Flood Risk Climate Total Raw Total Rank order applicable to reach International National Regional/Local overall ecology Strategy Statutory Non‐statutory Environment: Feasibility & form & function [C.c] Change & Score weighted Designation (SAC) Designation (SSSI) designation (BAP) [A.d] objectives Stakeholders Stakeholders Archaeology; practicality [C.b] sustainability (highest score [A.a] [A.b] [A.c] (Wildlife & (EA; NE; BDC; (anglers; owners; landscape; [C.a] [C.d] possible Fisheries & River NCC) [B.b] occupiers) [B.c] recreation [B.d] score 24) Form & Process) [B.a]

Individual weighting factor = 0.8 1 0.6 0.5 0.9 0.81 0.81 0.36 0.8 0.8 0.8 0.64 Option No. Option / measure G1: Do Nothing: No maintenance or restoration: raw score Y ‐1 ‐1 ‐10‐2 ‐1 ‐1 ‐121‐1 ‐1 Weighted score ‐0.8 ‐1 ‐0.6 0 ‐1.8 ‐0.81 ‐0.81 ‐0.36 1.6 0.8 ‐0.8 ‐0.64 ‐5.22 G2: Do Minimum: minimal restoration: raw score Y ‐1 ‐1 ‐10‐1 ‐11 01100‐2 Weighted score ‐0.8 ‐1 ‐0.6 0 ‐0.9 ‐0.81 0.81 0 0.8 0.8 0 0 ‐1.7 G3: Targeted Maintenance: Raw score Y 0 0111111111110 Weighted score 0 0 0.6 0.5 0.9 0.81 0.81 0.36 0.8 0.8 0.8 0.64 7.02 10 G4: Continue as present: raw score Y ‐1 ‐1 ‐1 ‐2 ‐2 ‐1 ‐102‐11 0‐7 Weighted score ‐0.8 ‐1 ‐0.6 ‐1 ‐1.8 ‐0.81 ‐0.81 0 1.6 ‐0.8 0.8 0 ‐5.22 G5: River Restoration G5a Mill Structures: 5.1m Mill structures - improve operability + protocols: raw score Y 1 111000020118 weighted score 0.8 1 0.6 0.5 0 0 0 0 1.6 0 0.8 0.64 5.94 5.2m Mill structures - remove flow control mechanisms: raw score Y 1 1111110211112 weighted score 0.8 1 0.6 0.5 0.9 0.81 0.81 0 1.6 0.8 0.8 0.64 9.26 8 5.3m Mill structures - lower mill sills levels Y 1 11121‐1 ‐1 ‐21 2 17 Weighted Score 0.8 1 0.6 0.5 1.8 0.81 ‐0.81 ‐0.36 ‐1.6 0.8 1.6 0.64 5.78 5.4m Mill structures – bypass channels (flow into IDB drain) N 0 Weighted Score 0 00000000000 0 5.5m Fish passes Y 1 0110111‐20‐114 Weighted Score 0.8 0 0.6 0.5 0 0.81 0.81 0.36 ‐1.6 0 ‐0.8 0.64 2.12 5.6m Mill structures - remove all N 0 Weighted Score 0 00000000000 0 G5b Gravel works: 5.7g Gravel glides Y 1 2212212220219 weighted score 0.8 2 1.2 0.5 1.8 1.62 0.81 0.72 1.6 1.6 0 1.28 13.93 1 H 5.8g Gravel glides + transverse hurdles: raw score Y 1 1221111110113 weighted score 0.8 1 1.2 1 0.9 0.81 0.81 0.36 0.8 0.8 0 0.64 9.12 5.9g Bed raising (large scale) Y 2 1112100‐11‐118 Weighted Score 1.6 1 0.6 0.5 1.8 0.81 0 0 ‐0.8 0.8 ‐0.8 0.64 6.15 G5c Other: 5.10 Fencing: Raw Score Y 0 001211021019 Weighted Score 0 0 0 0.5 1.8 0.81 0.81 0 1.6 0.8 0 0.64 6.96 11 5.11 Tree planting on top of bank: raw score Y 0 101111120019 Weighted score 0 1 0 0.5 0.9 0.81 0.81 0.36 1.6 0 0 0.64 6.62 12 L 5.12 Tree thinning: raw score Y 1 1122222210016 weighted score 0.8 1 0.6 1 1.8 1.62 1.62 0.72 1.6 0.8 0 0 11.56 3 5.13 Deflector (using LWD and filled in with brush mattress) Y 1 212211122‐1115 weighted score 0.8 2 0.6 1 1.8 0.81 0.81 0.36 1.6 1.6 ‐0.8 0.64 11.22 5 5.14 Lower spoil embankments Y 0 0012211‐11 1 210 weighted score 0 0 0 0.5 1.8 1.62 0.81 0.36 ‐0.8 0.8 0.8 1.28 7.17 9 5.15 Channel Re-sectioning Y 1 2120122121217 weighted score 0.8 2 0.6 1 0 0.81 1.62 0.72 0.8 1.6 0.8 1.28 12.03 2 5.16 Berm creation where appropriate Y 1 211221122‐1115 weighted score 0.8 2 0.6 0.5 1.8 1.62 0.81 0.36 1.6 1.6 ‐0.8 0.64 11.53 4 5.17 Backwaters – reconnections to IDB, field drains Y 0 1220211211114 weighted score 0 1 1.2 1 0 1.62 0.81 0.36 1.6 0.8 0.8 0.64 9.83 7 5.18 Backwaters - new Y 0 112010010017 weighted score 0 1 0.6 1 0 0.81 0 0 0.8 0 0 0.64 4.85 13 L 5.19 Channel realignment Y 1222‐1212120115 weighted score 0.8 2 1.2 1 ‐0.9 1.62 0.81 0.72 0.8 1.6 0 0.64 10.29 6 5.20 Changing primary and secondary channels (e.g. Ryburgh) N 0 weighted score 00000000000 0 5.21 Lower embankments Y 0 0010‐2 ‐2 ‐1 ‐21 1 2‐2 Weighted Score 0 000.50‐1.62 ‐1.62 ‐0.36 ‐1.6 0.8 0.8 1.28 ‐1.82

G6: Alternative Options 6.1 Increase Main river maintenance: raw score Y ‐2 ‐2 ‐2 ‐2 ‐2 ‐22 10‐21‐2 ‐12 Weighted score ‐1.6 ‐2 ‐1.2 ‐1 ‐1.8 ‐1.62 1.62 0.36 0 ‐1.6 0.8 ‐1.28 ‐9.32 6.2 Increase main river & IDB channel maintenance: raw score Y ‐2 ‐2 ‐2 ‐2 ‐2 ‐22 01‐21‐2 ‐12 Weighted score ‐1.6 ‐2 ‐1.2 ‐1 ‐1.8 ‐1.62 1.62 0 0.8 ‐1.6 0.8 ‐1.28 ‐8.88 6.3 Mill Structures - reinstatement & maintenance + hydropower Y ‐2 ‐2 ‐1 ‐1 ‐2 ‐21 1‐2 ‐2 ‐1 ‐1 ‐14 Weighted Score ‐1.6 ‐2 ‐0.6 ‐0.5 ‐1.8 ‐1.62 0.81 0.36 ‐1.6 ‐1.6 ‐0.8 ‐0.64 ‐11.59 Total Score 8.2 21 18.6 28.5 17.2 22.72 31.77 21.4 32.2 26 11.8 27.24 Key Score Description Mean: 9.41 2 High Relevance SD: 2.68 1 Low Relevance 0Neutral High imp: >12.08 ‐1Low Detriment Low imp: <6.73 ‐2High Detriment

Unit 47 Tatterford Common to Fakenham Mill_Final.docx 76 River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Table 5.11 - Results of MCA for Reach 30 (South Mill Reach)

River Wensum Multi Criteria Analysis River 47 Criteria Group Ecology [A] Project Delivery [B] Technical [C] Unit: Wensum Group weighting 10.90.8Reach: 30 South Mill Individual weighting within group 0.8 1 0.6 0.5 1 0.9 0.9 0.4 1 1 1 0.8 Length: 665m Criteria Option / measure Compliance with Compliance with Compliance with Contribution to Compliance with Compliance with Agreement with Human Technical Geomorphic Flood Risk Climate Total Raw Total Rank order applicable to reach International National Regional/Local overall ecology Strategy Statutory Non‐statutory Environment: Feasibility & form & function [C.c] Change & Score weighted Designation (SAC) Designation (SSSI) designation (BAP) [A.d] objectives Stakeholders Stakeholders Archaeology; practicality [C.b] sustainability (highest score [A.a] [A.b] [A.c] (Wildlife & (EA; NE; BDC; (anglers; owners; landscape; [C.a] [C.d] possible Fisheries & River NCC) [B.b] occupiers) [B.c] recreation [B.d] score 24) Form & Process) [B.a]

Individual weighting factor = 0.8 1 0.6 0.5 0.9 0.81 0.81 0.36 0.8 0.8 0.8 0.64 Option No. Option / measure G1: Do Nothing: No maintenance or restoration: raw score Y ‐2 ‐2 ‐1 ‐1 ‐2 ‐1 ‐1 ‐120‐1 ‐1 ‐11 Weighted score ‐1.6 ‐2 ‐0.6 ‐0.5 ‐1.8 ‐0.81 ‐0.81 ‐0.36 1.6 0 ‐0.8 ‐0.64 ‐8.32 G2: Do Minimum: minimal restoration: raw score Y ‐1001‐10‐101100 0 Weighted score ‐0.8 0 0 0.5 ‐0.9 0 ‐0.81 0 0.8 0.8 0 0 ‐0.41 G3: Targeted Maintenance: Raw score Y 0111‐111012018 Weighted score 010.60.5‐0.9 0.81 0.81 0 0.8 1.6 0 0.64 5.86 9 G4: Continue as present: raw score Y ‐1 ‐1 ‐1 ‐1 ‐1 ‐10 12‐11‐1 ‐4 Weighted score ‐0.8 ‐1 ‐0.6 ‐0.5 ‐0.9 ‐0.81 0 0.36 1.6 ‐0.8 0.8 ‐0.64 ‐3.29 G5: River Restoration G5a Mill Structures: 5.1m Mill structures - improve operability + protocols: raw score N 0 weighted score 0 00000000000 0 5.2m Mill structures - remove flow control mechanisms: raw score N 0 weighted score 0 00000000000 0 5.3m Mill structures - lower mill sills levels Y 0 00120‐10‐20 0 00 Weighted Score 0000.51.80‐0.81 0 ‐1.6 0 0 0 ‐0.11 5.4m Mill structures – bypass channels (flow into IDB drain) N 0 Weighted Score 0 00000000000 0 5.5m Fish passes N 0 Weighted Score 0 00000000000 0 5.6m Mill structures - remove all N 0 Weighted Score 0 00000000000 0 G5b Gravel works: 5.7g Gravel glides Y 1 2210211220216 weighted score 0.8 2 1.2 0.5 0 1.62 0.81 0.36 1.6 1.6 0 1.28 11.77 2 H 5.8g Gravel glides + transverse hurdles: raw score N 0 weighted score 0 00000000000 0 5.9g Bed raising (large scale) Y 1 111010011‐117 Weighted Score 0.8 1 0.6 0.5 0 0.81 0 0 0.8 0.8 ‐0.8 0.64 5.15 G5c Other: 5.10 Fencing: Raw Score Y 0 1121110210111 Weighted Score 0 1 0.6 1 0.9 0.81 0.81 0 1.6 0.8 0 0.64 8.16 5 5.11 Tree planting on top of bank: raw score Y 0 1012102200110 Weighted score 0 1 0 0.5 1.8 0.81 0 0.72 1.6 0 0 0.64 7.07 7 5.12 Tree thinning: raw score Y 0 101011020017 weighted score 0 1 0 0.5 0 0.81 0.81 0 1.6 0 0 0.64 5.36 10 L 5.13 Deflector (using LWD and filled in with brush mattress) Y 0 1120111210111 weighted score 0 1 0.6 1 0 0.81 0.81 0.36 1.6 0.8 0 0.64 7.62 6 5.14 Lower spoil embankments N 0 weighted score 0 00000000000 0 5.15 Channel Re-sectioning Y 0 011120111019 weighted score 0 0 0.6 0.5 0.9 1.62 0 0.36 0.8 0.8 0 0.64 6.22 8 5.16 Berm creation where appropriate Y 1 1111211220114 weighted score 0.8 1 0.6 0.5 0.9 1.62 0.81 0.36 1.6 1.6 0 0.64 10.43 3 5.17 Backwaters – reconnections to IDB, field drains Y 1 12221‐10211113 weighted score 0.8 1 1.2 1 1.8 0.81 ‐0.81 0 1.6 0.8 0.8 0.64 9.64 4 5.18 Backwaters - new N 0 0 weighted score 0 00000000000 0 5.19 Channel realignment Y 2 22221‐12121117 weighted score 1.6 2 1.2 1 1.8 0.81 ‐0.81 0.72 0.8 1.6 0.8 0.64 12.16 1 H 5.20 Changing primary and secondary channels (e.g. Ryburgh) N 0 weighted score 0 00000000000 0 5.21 Lower embankments N 0 Weighted Score 0 00000000000 0

G6: Alternative Options 6.1 Increase Main river maintenance: raw score Y 0001‐2 ‐22 01‐10‐1 ‐2 Weighted score 0000.5‐1.8 ‐1.62 1.62 0 0.8 ‐0.8 0 ‐0.64 ‐1.94 6.2 Increase main river & IDB channel maintenance: raw score N 0 Weighted score 0 00000000000 0 6.3 Mill Structures - reinstatement & maintenance + hydropower N 0 Weighted Score 0 00000000000 0 Total Score 5.6 20 17 25 9.6 19.1 6.43 11.88 37.6 21.6 2.8 15.76 Key Score Description Mean: 8.43 2 High Relevance SD: 2.45 1 Low Relevance 0Neutral High imp: >10.88 ‐1Low Detriment Low imp: <5.98 ‐2High Detriment

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Table 5.12 - Results of MCA for Reach 31 (Confluence Reach)

River Wensum Multi Criteria Analysis River 47 Criteria Group Ecology [A] Project Delivery [B] Technical [C] Unit: Wensum Group weighting 1 0.9 0.8 Reach: 31 Confluence Individual weighting within group 0.8 1 0.6 0.5 1 0.9 0.9 0.4 1 1 1 0.8 Length: 475m Criteria Option / measure Compliance with Compliance with Compliance with Contribution to Compliance with Compliance with Agreement with Human Technical Geomorphic Flood Risk Climate Total Raw Total Rank order applicable to reach International National Regional/Local overall ecology Strategy Statutory Non‐statutory Environment: Feasibility & form & function [C.c] Change & Score weighted Designation (SAC) Designation (SSSI) designation (BAP) [A.d] objectives Stakeholders Stakeholders Archaeology; practicality [C.b] sustainability (highest score [A.a] [A.b] [A.c] (Wildlife & (EA; NE; BDC; (anglers; owners; landscape; [C.a] [C.d] possible Fisheries & River NCC) [B.b] occupiers) [B.c] recreation [B.d] score 24) Form & Process) [B.a]

Individual weighting factor = 0.8 1 0.6 0.5 0.9 0.81 0.81 0.36 0.8 0.8 0.8 0.64 Option No. Option / measure G1: Do Nothing: No maintenance or restoration: raw score Y ‐1 ‐1 ‐10 0‐1 ‐2 ‐1210‐1 ‐5 Weighted score ‐0.8 ‐1 ‐0.6 0 0 ‐0.81 ‐1.62 ‐0.36 1.6 0.8 0 ‐0.64 ‐3.43 G2: Do Minimum: minimal restoration: raw score Y 0 ‐10010‐1011001 Weighted score 0 ‐10 00.90‐0.81 0 0.8 0.8 0 0 0.69 G3: Targeted Maintenance: Raw score Y 0000‐111111116 Weighted score 0000‐0.9 0.81 0.81 0.36 0.8 0.8 0.8 0.64 4.12 8 G4: Continue as present: raw score Y ‐1 ‐2 ‐1 ‐2 ‐1 ‐10‐12‐10 0‐8 Weighted score ‐0.8 ‐2 ‐0.6 ‐1 ‐0.9 ‐0.81 0 ‐0.36 1.6 ‐0.8 0 0 ‐5.67 G5: River Restoration G5a Mill Structures: 5.1m Mill structures - improve operability + protocols: raw score N 0 weighted score 0 00000000000 0 5.2m Mill structures - remove flow control mechanisms: raw score N 0 weighted score 0 00000000000 0 5.3m Mill structures - lower mill sills levels N 0 Weighted Score 0 00000000000 0 5.4m Mill structures – bypass channels (flow into IDB drain) N 0 Weighted Score 0 00000000000 0 5.5m Fish passes N 0 Weighted Score 0 00000000000 0 5.6m Mill structures - remove all N 0 Weighted Score 0 00000000000 0 G5b Gravel works: 5.7g Gravel glides Y 1211‐111001018 weighted score 0.8 2 0.6 0.5 ‐0.9 0.81 0.81 0 0 0.8 0 0.64 6.06 6 5.8g Gravel glides + transverse hurdles: raw score N 0 weighted score 0 00000000000 0 5.9g Bed raising (large scale) N 0 Weighted Score 0 00000000000 0 G5c Other: 5.10 Fencing: Raw Score Y 1 2122110220115 Weighted Score 0.8 2 0.6 1 1.8 0.81 0.81 0 1.6 1.6 0 0.64 11.66 1 H 5.11 Tree planting on top of bank: raw score Y 0 101010121018 Weighted score 0 1 0 0.5 0 0.81 0 0.36 1.6 0.8 0 0.64 5.71 7 5.12 Tree thinning: raw score Y 0 101011021018 weighted score 0 1 0 0.5 0 0.81 0.81 0 1.6 0.8 0 0.64 6.16 5 5.13 Deflector (using LWD and filled in with brush mattress) Y 1 2111101110111 weighted score 0.8 2 0.6 0.5 0.9 0.81 0 0.36 0.8 0.8 0 0.64 8.21 3 5.14 Lower spoil embankments Y 0 11221‐11011110 weighted score 010.611.80.81‐0.81 0.36 0 0.8 0.8 0.64 7 4 5.15 Channel Re-sectioning Y 0 001010101116 weighted score 0 0 0 0.5 0 0.81 0 0.36 0 0.8 0.8 0.64 3.91 9 L 5.16 Berm creation where appropriate Y 1 2120201120113 weighted score 0.8 2 0.6 1 0 1.62 0 0.36 0.8 1.6 0 0.64 9.42 2 H 5.17 Backwaters – reconnections to IDB, field drains Y 011‐1 ‐1 ‐1 ‐201001‐1 weighted score 010.6‐0.5 ‐0.9 ‐0.81 ‐1.62 0 0.8 0 0 0.64 ‐0.79 5.18 Backwaters - new Y 0 11100‐1110015 weighted score 010.60.500‐0.81 0.36 0.8 0 0 0.64 3.09 10 L 5.19 Channel realignment N 0 weighted score 0 00000000000 0 5.20 Changing primary and secondary channels (e.g. Ryburgh) N 0 weighted score 0 00000000000 0 5.21 Lower embankments N 0 Weighted Score 0 00000000000 0

G6: Alternative Options 6.1 Increase Main river maintenance: raw score Y ‐1 ‐10‐2 ‐2 ‐20 01‐10‐1 ‐9 Weighted score ‐0.8 ‐10‐1 ‐1.8 ‐1.62 0 0 0.8 ‐0.8 0 ‐0.64 ‐6.86 6.2 Increase main river & IDB channel maintenance: raw score Y ‐1 ‐10‐2 ‐2 ‐20 01‐10‐1 ‐9 Weighted score ‐0.8 ‐10‐1 ‐1.8 ‐1.62 0 0 0.8 ‐0.8 0 ‐0.64 ‐6.86 6.3 Mill Structures - reinstatement & maintenance + hydropower N Weighted Score 0 00000000000 0 Total Score 11597.5‐3.8 6.43 ‐3.43 7.8 30.4 17 5.4 14.12 Key Score Description Mean: 6.53 2 High Relevance SD: 2.5 1 Low Relevance 0Neutral High imp: >9.04 ‐1Low Detriment Low imp: <4.03 ‐2High Detriment

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5.3.1 Results of the MCA options appraisal The MCA is not just about which options improve ecology. As discussed, implicit in the MCA is the assessment of options and measures against other issues such as flood risk, the human environment, construction feasibility and agreement with landowners and stakeholders. Assessing these issues alongside ecological factors allows the options and measures to be assessed realistically, and to identify where other issues may conflict with the objective of achieving ‘unfavourable recovering’ or ‘favourable’ ecological condition for the SSSI, and good ecological potential for the Wensum under the Water Framework Directive. It should be noted that information from the environmental baseline and stakeholder consultation specific to each reach was applied to the MCA for that reach. The results from the MCA do differ for each of the reaches in Unit 47 but have a number of similarities including:  The options of ‘Do nothing’, ‘Continue as present’ and ‘Alternative options’ all produced negative scores.  The option of ‘Do Minimum’ produces mostly negative scores (the exceptions being in reaches 28 and 31, where the option of doing minimal restoration is assessed as being positive in term of delivering the RWRS, although it scores significantly lower than Targeted Maintenance).  The options of ‘Targeted maintenance’ and’ River restoration’ all produced positive scores. A negative score indicates that the option is detrimental to the project’s objectives of achieving ‘unfavourable recovering’ or ‘favourable’ condition status for the River Wensum. This suggests that ‘Do nothing’ (i.e. abandoning the river) is not an option and work is required to achieve the objective. This is surprising as a popular notion within the river restoration community is that sometimes allowing the river ‘to sort itself out’ can be viewed as the best option, particularly if maintenance is considered to be harming the river condition rather than improving it. In the case of Unit 47, the overall impact of Fakenham Mill on the form, function and ecology of the impounded upstream reaches (Reach 26 and part Reach 27) is so significant, that the ‘Do nothing’ option will not change this impact and action to address the impoundment is required prior to the implementation of any instream restoration measures in Reach 26. The options of ‘Do minimum’ and ‘Continue as present’ are considered detrimental to the restoration project objectives, although constraints associated with the use of the site as an existing EA stream flow gauge are considered to lessen options for attaining ‘free flow’ upstream of the mill. The ‘Alternative options’ also received negative scores and this is largely a consequence of the scores attributed to the ‘Ecology’ criteria. This applies to hydropower options, which involve the generation of energy through harnessing the kinetic energy of water. Hydropower is seemingly attractive, as it is a form of renewable and ‘clean’ energy with added benefits such as reusing historic structures along watercourses. Hydropower is being implemented elsewhere and the Environment Agency has produced a position statement (2009a) and guidance (2009b) on how such projects should be developed, assessed and implemented. Similarly, Natural England has also developed a draft position on hydropower which is available on their website. When assessed against both the MCA and Environment Agency and Natural England guidance, the implementation of hydropower schemes for the River Wensum has been found to score negatively. Impacts on geomorphology, hydraulics, flow regimes and biological connectivity may have an adverse effect on flora and fauna (e.g. fish). Thus, whilst providing some benefits, hydropower ultimately runs counter to the high-level project objectives for geomorphological and ecological enhancement. Any likely wider benefits of renewable energy are negated by the potential for adverse local effects on other natural resources and receptors.

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Options and measures with negative scores will not be progressed as part of the River Wensum Restoration Project as they will not improve the ecological or geomorphological condition of the river. The MCA has demonstrated that the options of ‘River restoration’ and ‘Targeted maintenance’ will help Unit 47 to achieve ‘unfavourable recovering’ or ‘favourable’ ecological condition. The ‘River restoration’ option has a number of associated measures with different scores. All of these scores are positive, indicating they should be included as part of the preferred restoration design. Additionally, each reach has a different score for each measure due to the results of the MCA reflecting the baseline condition of the reach. The top scoring measures for each reach are given in Table 5.13.

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Table 5.13 - Summary of favourable options and measures for Unit 47

Term Reach 26 Reach 27 Reach 28 Reach 29 Reach 30 Reach 31 River River River River River River Restoration Restoration Restoration Restoration Restoration Restoration

Favourable options Targeted Targeted Targeted Targeted Targeted Targeted Maintenance Maintenance Maintenance Maintenance Maintenance Maintenance

Do Minimum Do Minimum Gravel glides Gravel glides Gravel glides Gravel glides Channel Fencing realignment Berm creation Channel re- Deflectors Channel re- Berm creation sectioning sectioning Gravel glides Tree thinning Berm creation Deflectors Top 5 Deflectors Tree thinning Berm creation River Restoration Mill structures - Tree thinning Lower spoil Measures improve Berm creation Berm creation Backwater embankments Channel operability + reconnections protocols Tree thinning realignment Deflectors Tree thinning Fencing Deflectors

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The value of the weighted scores provides an indication of the relative importance of the measures in achieving ‘unfavourable recovering’ or ‘favourable’ ecological condition for the reach and suggests the order in which measures could be applied. This provides a useful indicator for identifying which opportunities to look for first in a reach. For example, in Reach 28 the highest scoring measure is gravel glides, so this is the first opportunity looked for in the reach, followed by the second highest measure, deflectors, and so on. All of the measures are valid so it is not recommended that a cut-off be imposed at a certain value. However, the positively scoring measures have been grouped into bands of importance to give an indication of their relative importance in restoring the reach to favourable condition (see section 6 for further details). The frequency, location and manner in which measures are applied requires professional judgement, informed by in-depth understanding of the baseline conditions of the reach. It is important to highlight that cost has not been included in the MCA as it is imperative that options and measures that move the reach towards achieving ‘unfavourable recovering’ or ‘favourable’ ecological condition are identified regardless of cost. Whilst cost is an important factor, it should not preclude an option or measure being identified and implemented. Instead, costs should be considered in terms of how options are implemented, and used to identify savings by using local material, phasing work appropriately or using different techniques (e.g. a LWD deflector compared with a concrete deflector) to achieve the same result at a lower cost. The MCA provides a powerful tool for appraising all options and associated measures in a consistent, replicable and transparent way. It should be noted that the MCA should be viewed as a filtering tool to allow favourable options to be identified and unfavourable options to be dropped. How those favourable options and measures are applied to a reach is a case of professional judgement, and this is discussed in Chapter 6.

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6. Developing Conceptual Design 6.1 Introduction and approach This chapter explains how the recommended options of ‘River restoration’ and ‘Targeted maintenance’ can be applied to each reach. To set this in context, the chapter initially details:  The project in the context of river restoration (Section 6.2.1).  How ecology has been integrated into the conceptual design process (6.2.2).  How ‘Targeted maintenance’ is included within the recommended option (Section 6.2.3). Reach objectives, their review, and preferred restoration measures for each for Reaches 26, 27, 28, 29, 30 and 31 are outlined in Sections 6.3 - 6.8, respectively.

6.2 Description of River Restoration and Targeted Maintenance options

6.2.1 River restoration theory The term river restoration can be used to describe a number of different activities that require different levels or magnitudes of change. River alteration projects form a continuum from ‘full restoration’ through to ‘erosion control’ (Plate 20). The range reflects the varying level of human intervention in natural systems to manage risk (Gillian et al., 2005).

Plate 20 – River channel projects differ from full restoration to erosion control measures This distinction between levels of work and sustainability was developed further in the geomorphological appraisal of the River Wensum, where Sear et al. (2006) categorised the geomorphology of reaches on the River Wensum into six management classes of river restoration (Table 6.1). This provides a method of quantifying the magnitude of restoration needed on a reach by reach basis depending on the baseline conditions and opportunity for change.

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Table 6.1 - Different management classes of restoration activity

Term Definition Restoration of channel processes and forms to pre-disturbance Restoration conditions. Physical modification to the river form to re-create physical habitats Rehabilitation (e.g. re-meandering, riffle installation, bed level raising). Addition of structural features to improve physical habitat diversity Enhancement (e.g. narrowing, woody debris). Afford legal protection to the site and monitor for change in status. Protect & monitor Given that the site has legal protection (SSSI / SAC), monitor to ensure that the status is maintained and take action if required. Amplification of existing processes to encourage recreation of physical Assisted natural habitats (e.g. encouraging berm formation to narrow channel, removal recovery of bank revetment to create sediment supply). Protect site against further degradation not necessarily with legal Conserve statute.

Sear et al. (2006) developed this further by categorising river restoration techniques into active and passive restoration based on the restoration approach of form mimicry or process based restoration (Table 6.2). This presents a range of typical river restoration measures that can be followed and all of these were included in the MCA analysis as all are applicable to the Wensum to varying degrees. Table 6.2 - Active and passive river restoration measures

Active Restoration – Passive Restoration – (physical (physical creation of forms manipulation of flow and or removal of structures to sediment transport regime to improve degraded create physical habitat and to ecosystems.) improve degraded ecosystems.) Form-mimicry – The re-creation of physical Gravel augmentation which then Riffle recreation habitat features without is moulded by river flows into bed Re-meandering. reference to the processes features (riffles). required to create them. Process-based restoration Mill weir removal – restores Reduction in catchment sediment The use of physical sediment connectivity and supply. processes to restore hydraulic gradient. Management of flow regime (flow degraded physical habitats to Re-occupation of an old re-naturalisation). a more natural form. channel course.

All six reaches in Unit 47 have been categorised into the ‘Rehabilitation’ Management class (see Table 6.1) (Sear et al., 2006; JBA, 2007). This is defined as: “Physical modification of the channel to re-create self sustaining physical habitats (e.g. riffles, side berms), generally where the channel is currently substantially over deep and / or over wide’’.

Therefore ‘Rehabilitation’ does not mean that the aim of the ‘River restoration’ option is to:  Return the river and floodplain to pre disturbance conditions;  Return the river to its high maintenance regime of wholesale dredging of the river channel; or  Return the functionality of the mill systems.

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The emphasis for Unit 47 is on changing present river form and flow processes to help the river develop conditions more typical of its chalk river type. This does not mean that this is undertaken in isolation to the wider issues and constraints of the catchment (e.g. flood risk to people and property). Rather, improving the river condition should aim to provide multiple benefits in terms of reducing flood risk, reducing the need for regular extensive maintenance by creating a self-sustaining system, creating managed ‘hotspots’ for ‘Targeted maintenance’, improving amenity value and improving habitat condition and diversity for a variety of flora and fauna. To do this, different restoration measures can be used to varying degrees. The density and type of river restoration measures can be applied in three ways to provide the following design philosophies:  Total Restoration Design Philosophy (High-density application of fully formed restoration features) – This approach provides ‘complete’ river restoration and is applicable when the river does not have the capacity to form features itself.  ‘Kick Start’ Restoration Design Philosophy (Medium-density application of partially formed features) – This approach uses the existing form and function of the river and provides in channel and out of channel features to allow the river to kick start natural geomorphological process by building upon the features provided.  Opportunistic Restoration Design Philosophy (Low-density application of fully formed features) – This approach is indicative of opportunistic river restoration design where restoration measures are applied to a short length of river due to favourable circumstances. This often provides improvement to the river condition locally but can have limited benefit for the river condition on a SSSI unit basis. River restoration that has been undertaken on the River Wensum in the past has been undertaken within the Opportunistic Restoration Design Philosophy. The RWRS has provided the opportunity to change this philosophy by providing a whole river vision and mechanism to achieve river restoration on a catchment scale. To achieve the vision of the RWRS, it is recommended that the ‘Kick Start’ Restoration Design Philosophy is applied for the following reasons:  The river is slowly recovering naturally from legacy maintenance practices, demonstrating the capacity to develop morphology features and ‘self heal’.  Whilst not ideal or recommended, modifications to mill operating regimes are likely to be undertaken at different timescales to river restoration. Consequently, implementing total restoration while mill structures are unchanged represents a future risk to the design if water levels change significantly.  It provides value for money by not installing features that the river can form naturally over time.  It allows a phased approach to be adopted by allowing the river time to adapt to river restoration measures before determining if additional measures are required. Therefore, the approach of ‘Kick Start’ Restoration Design Philosophy, within the context of the ‘Rehabilitation’ management class for the River Wensum, is to deliver the minimal amount of physical works in the river that will achieve sufficient change in hydromorphological form and fluvial processes to accelerate the river’s natural ability to ‘self-heal’. More specifically the design philosophy is to: 1. Restore the river to a form and function characteristic of a Norfolk chalk river.

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2. Put forward recommendations that will see restoration measures implemented in 2010 to help restore ‘unfavourable recovering’ or ‘favourable’ ecological condition to the SSSI habitat features.

3. Provide a ‘kick-start’ by only undertaking works to create features that the river would not be able to do itself.

4. Provide an increase in the patchiness and diversity of features that are sufficient to allow an improvement in natural processes and which will increase both the rate, and amount of self- restoration at any point along the unit.

5. Provide sufficient strength of processes that will allow significant self-restoration by 2015 to meet WFD timeframes.

6. Place measures at an appropriate frequency of 20m to match present day flow rates and erosion / deposition patterns. However, they must also respect the larger channel form features such as the relic bend length of 35m derived from ancient river flow rates. This will ensure there is sustainability over any likely range of flow rates, and their associated erosion / deposition patterns.

7. Ensure that the channel forms provide durable results against the varying flows and water levels generated by long-term climate change impacts, and in-channel vegetation growth in the short-term.

In respect to point 1 above, it is recognised that the River Wensum, and other Norfolk chalk rivers, are slightly different from ‘classic’ chalk rivers. This is explored in detail in section 3.2 and the Geomorphological Appraisal of the River Wensum by Sear et al. (2006) and also summarised in the JBA report (2007). 6.2.2 Designing for ecology The restoration strategy applied to each reach must provide a measurable ecological benefit at both a species and community scale in order for the River Wensum to achieve ‘favourable’ ecological condition. Ecological monitoring of river restoration sites will be one of the key ways of assessing the success of implementing the strategy. Equally, prior to the implementation of specific river restoration measures, consideration must be given to the potential for harm to be caused to existing ecological features through direct damage, loss of habitat, or alteration to existing river form and function. The permanency of any effect, adverse or beneficial, will need to be assessed as well as the potential for natural recovery within the system. This process has required an extensive ecological baseline review of the distribution and status of ecological features in the River Wensum, as discussed in Section 3. This has been coupled with the identification of physical habitat constraints and catchment scale pressures that are influencing condition status. Furthermore, a detailed review of the SSSI / SAC interest features has been undertaken to promote appropriate restoration measures for these key species and community assemblages. It is important to note that at this stage the review has concentrated on designated ecological features only, although the intention is to add additional ecological features, following consultation with statutory stakeholders. The following information has been collated for each of the key ecological features through extensive literature and data review:  Protected status and UK distribution.

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 General ecology e.g. life cycle, feeding requirements.  Specific habitat requirements for all life stages, including: - Substrate - Water quality - Water quantity, and  Factors known to currently affect species / community distribution and populations. For each of the Strategy wide restoration measures (e.g. tree thinning, gravel glide placement), both the positive and negative effects of implementation has been determined through an initial identification of the habitat requirements for each species and community. Following this, an assessment was made of how the habitat may alter following implementation of a river restoration measure and the resultant impact, adverse or beneficial, that this could have on species distribution and community persistence. The recommended restoration measures that were identified using the MCA are displayed in Table 6.3 along with the associated potential ecological benefits to different species and communities. These benefits will arise by ensuring that the adopted restoration measures are integrated (e.g. berms are installed to promote favourable flow over the top of installed gravel glides). Integrated measures to maintain appropriate geomorphic form and function and maximum ecological benefit will ensure resilience and persistence of the ecological communities that develop. Further details of how the measures benefit the designated species and communities can be found in Appendix C. Table 6.3 - River restoration measures and their potential ecological benefits

Restoration Measure Description & Potential Ecological Benefits Fencing constructed landward of the river bank to prevent bank erosion from the impacts of cattle grazing, with a consequent reduction in sediment ingress. Protects marginal habitat and Fencing promotes growth of emergent and marginal / aquatic plants, with associated improvement for aquatic macroinvertebrate fauna (e.g. Desmoulin's whorl snail Vertigo moulinsiana). Tree planting to cast shade over the water to control excessive macrophyte growth, provide cover for fish and to develop Tree planting erosion resistance from root reinforcement. Also provides input of leaf litter and LWD of value to macroinvertebrate fauna including white-clawed crayfish. Selective felling or lopping to provide light onto the water to encourage marginal and submerged macrophyte development Tree thinning and associated macroinvertebrates. In addition, this will generate appropriate materials for use in restoration measures, e.g. brush-fill and deflectors. Downstream pointing LWD placed and secured at the upstream side of the deflector to create flow diversity; in-filled Deflectors downstream with brush to promote silt deposition and marginal (using LWD and filled in plant growth. Provides refuge for fish fry behind structure and with brush mattress) good flow diversity for macroinvertebrates and submerged macrophytes (e.g. Ranunculion fluitantis and Callitricho- Batrachion vegetation). Removal of dredging-based informal embankments to allow out-of-bank flow across the floodplain, and back into the river. Lower spoil embankments Ensures fish that are washed out of the channel during flood can return to the river as the floodwaters recede. May also improve adjacent wetland systems through water level regime.

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Restoration Measure Description & Potential Ecological Benefits Horizontal lowering of bank top up to half the channel width to increase flood flow capacity and generate arisings for bed raising where no embankments exist. Creates marginal shelf Berm creation habitat for macrophytes and associated fauna plus refuges from high flows for fish fry. Improvement to instream flow conditions. Utilizing existing wet features by connecting them to the river to create essential refuge habitat for fish and other fauna. This Backchannels – measure is implemented to aid the natural recruitment of fish reconnections to IDB and existing field drains stocks. Achieved through provision of nursery habitat and refuge from high-flow events. Additional utilisation by a variety of aquatic biota, e.g. brook lamprey ammocoetes. Creating habitat where no other water bodies exist e.g. dog-leg with downstream end open and upstream end fed by Backchannels – create percolation. This measure provides refuge for fish and a place new features for fry to rest during floods, so limiting the loss of fry to reaches downstream of mill structures. Benefits all fish species through increasing recruitment potential. Creation of short lengths of full raised bed, dressed in gravel to create variation in flow and habitat for various Gravel riffles macroinvertebrates and macrophytes in addition to provision of spawning substrate for fish species, e.g. trout, barbel and brook lamprey. Creation of long lengths of full width raised bed, dressed in gravel, to reconnect channel with floodplain and create Bed raising variation in flow and habitat for various fish species, macroinvertebrates and macrophytes. Full depth excavation from bank top to increase lateral Channel realignment to variation in planform, either one bank or both, using arisings to increase river sinuosity infill opposite bank. Improved geomorphological form and function beneficial to a range of associated biota.

Each of these measures has a different effect dependant on the flows in the river. Table 6.4 summarises the relationship between flow height and impact.

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Table 6.4 - The effect of river restoration measures according to flow condition

River Flow / Level Mill Structures Gravel Glides Deflectors New Backchannels Reconnection Backchannel Creation Berm Realignment Channel Re-sectioning Channel of Embankment Removal of Spoil Removal Tree Thinning Tree Planting Fencing Over bank I I D D D D D

Bank full D I I I D I D D D I

High flow D I I D D D D D I

Low flow D D D D I D D I Key: I=Indirect; D=Direct The effects can be direct (D), such as deflectors which will physically push flow across the river at low flows. Higher flows will go over the top of the deflector and therefore there will be no direct effects. However, the impact at low flow will have changed local silt deposition and hence vegetation patterns. The combined effect of the deflector and the vegetation will have an impact on the higher flows, but this depends on several factors such as plant growth; this effect is described as indirect (I). The combination of each of the different measures ensures that process and form of the river is impacted under all flows and so will increase the rate of change towards self-healing. From an ecological view it means that conditions within the channel vary so that biota can move to similar conditions, but in a different location, as flow increases. 6.2.3 Targeted maintenance The ‘Targeted maintenance’ option recognises that there is a need for some maintenance to be undertaken on the River Wensum due to the various pressures that limit the potential for the channel to be a totally self-cleansing and regulating system. It is also an option that can be undertaken while river restoration measures are being designed and implemented. A separate targeted maintenance protocol is being developed which sets out in more detail where, how, when and by whom maintenance will be undertaken. The protocol will allude where possible to policies such as those contained in the Broadland Rivers Catchment Flood Management Plan, specifically the reduction in maintenance of fluvial systems. In addition, the protocol will draw upon consultation with internal Environment Agency functions and other stakeholders and will have regard to current maintenance practices. The measures that are included within the ‘Targeted maintenance’ option are outlined in Sections 6.2.4 to 6.2.7. 6.2.4 Silt removal at identified ‘hotspots’ These are sections of the river where silt accumulation will have an operational impact in terms of flood risk management. Maps indicating the distribution of ‘hot spots’ on the River Wensum were received from the Water Management Alliance on behalf of the Norfolk Rivers IDB. Typically these are sections of channel upstream of mill structures where silt deposits interfere with the flow of water approaching the structure, and limit the structure’s capacity, so increasing local flood risk. Generally it is recommended that a 200m length of channel upstream of each mill is targeted for

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de-silting. This will also allow the character of the mill leat to remain. Without the implementation of river restoration and lowering of levels at mills, desilted sections of river will tend to accumulate fresh deposits of silt. The desilting operation is therefore not sustainable in the long term. It is worth noting, too, that Norfolk chalk rivers have a higher sand content in the river substrate than a typical chalk river, in downstream sections, as a result of ingress of material from the drift. Restoration and targeted maintenance will not seek to remove these features and will work with them. 6.2.5 Clearance of main channel immediately downstream of identified IDB drain outfalls This is to allow the IDB drains to discharge freely, otherwise their ability to flow freely is compromised, which in turn increases siltation, and so increases the need for maintenance in areas which are often valuable as nursery habitat for fish. The inability to discharge also increases flood risk from the drain, which in some instances will significantly impact on property flooding. It is recommended that 100m downstream of confluences are regularly inspected and cleared of silt and excessive marginal vegetation if necessary. 6.2.6 Clearance or realignment of fallen trees blocking the channel Clearance of fallen trees only needs to occur if they are within the impounded section immediately upstream of the mills, or the 100m stretch downstream of IDB drain confluences, or are impacting directly on flood risk to houses, such as river blockages at bridges. Otherwise, the trees should be re-aligned to provide flow diversity, and LWD. Trees may present a problem on impounded river reaches, as they may assist a breach in a river bank where the river is a high level carrier. This is undesirable, in that the objective of the strategy is to manage change, rather than to allow unchecked natural change. 6.2.7 Strategic weed cutting This should only be carried out where there is a direct flood threat to houses caused by elevated water levels, or where freeboard is unlikely to be sufficient to receive likely rainfall. It is likely to be required in the 200m mill leat and 100m IDB drain confluence sections. As these are discrete sections, where access is reasonable, the use of weed cutting bucket equipped excavators can be used, without the need for weed boats to travel substantial lengths of the river. This removes the need for tree management to allow passage of a weedboat, or to allow cut weed to float downstream to a designated pull-out point.

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6.3 Reach 26: Fakenham Reach This section defines the preferred restoration of Reach 26 by describing key existing features; reviewing the recommended measures as stated in the RWRS; presenting the results of the MCA scoring and detailing rehabilitation measures applied to the reach. 6.3.1 Key existing features influencing proposed restoration measures Table 6.5 presents a brief description of the existing conditions of the reach as observed during the site visit conducted on 13th August 2010. The purpose of the visit was to consider the reach objectives on the ground. Table 6.5 - Significant features and possible measures observed for Reach 26 during site visit

Noted Feature Possible Measure Lower / remove flow control structures to improve flow conditions throughout reach. This measure The reach is significantly affected by the will conflict with the existing Environment Agency backwater created by flow control structures flow gauge at this location. However, at Fakenham Mill. continuation of existing flow character precludes cost effective installation of measures outlined below. Create sinuosity through installation of berms Channel heavily modified, straightened, over and deflectors. Raise bed through gravel wide and over deep on approach to placement in conjunction with channel narrowing Fakenham Mill. measures. Tree thinning to encourage natural narrowing and River margin is heavily shaded on approach use of arisings to provide material for structures to mill on TLHB. to promote self-narrowing. Move silt by change in flow patterns and local bed raising. Encourage selective marginal Extensive siltation throughout the reach. vegetation encroachment as silt management measure. Natural / enhanced vegetation on lower bank Heavy management of neighbouring needs to grow naturally to provide bank erosion floodplain and the upper banks. control.

6.3.2 Review of Reach 26 Strategy Objectives Appendix A to the RWRS (JBA, 2007) details a ‘Reach Restoration Strategy’ for each reach. These objectives have been the starting point for the consideration of rehabilitation activities within each reach. A review of these objectives is presented below in Table 6.6.

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Table 6.6 - Review of strategy objectives and recommendations for Reach 26

RWRS Objectives Atkins Comments on the RWRS All works to integrate with lowering of Agree: Objective appropriate to this reach 1.1 structure at Fakenham Mill and to reduce impoundment and backwater associated river works. effect. Integrate with proposed flood risk Partially Agree: Capital project is not 1.2 management capital project and link proceeding. However, any works should with existing enhancements. link to existing enhancement on TRHB. Disagree: This reach acts as a mill leat and as such within the targeted maintenance protocol it is to be used as a De-silt channel just upstream of 1.3 silt entrapment area in the absence of Fakenham Mill. alteration to the mill structures. However, levels do need to be monitored for possible silt control in the future. Agree: Encouraging the development of marginal vegetation is key to starting river Encourage development of marginal / 1.4 processes and improving form, habitat and bankside vegetation. ecological value. Also provides bank erosion control. Partially Agree: Local gravel yields are likely to be low. Bed raising and gravel Augment bed on average by 1.4m using glide placement will improve instream local gravels wherever possible and 2.1 habitat, although recommended wide scale create up to 11 gravel glides or riffles in augmentation by 1.4m will be costly and this reach. unnecessary should only be considered if mill structures are lowered. Channel narrowing (with associated Partially Agree: Channel is significantly landscaping and fencing) may have to over wide and requires narrowing alongside 2.2 be considered to restore the full actions to encourage marginal plant functioning of the channel in this reach development. However, fencing is not following works at the mill. appropriate to current land uses. Adopt / maintain maintenance regime Partially Agree: Channel is significantly and riparian management and allow modified and therefore any maintenance 2.3 channel to create natural variations in regime is unlikely to improve condition in local channel width and habitat niches. isolation. Agree: Monitoring required alongside any Post-project monitoring is required, mill work to ascertain magnitude of changes 2.4 especially in association with works at in flow and level and requirements for silt the mill. management. Partially Agree: CWD is beneficial in terms Maintain coarse woody debris (CWD) in 2.5 of habitat provision although likely to conflict the channel. with flood risk in this reach. Summary Reach 26: Atkins agrees or partially agrees with the majority of the principles established by JBA for this reach. The only disagreement relates to silt removal requirements. This variation is not surprising given the different level of analysis undertaken at the two different stages of the project.

6.3.3 Reach 26: Recommended Restoration This section provides the details of the options and measures proposed for this reach which have been derived from the Multi-Criteria Analysis (refer to Section 5.3). A summary of the MCA results in their rank order is provided in Table 6.7 and these are further divided into importance according to how far the measure will move the reach towards achieving ‘unfavourable recovering’ or ‘favourable’ ecological condition.

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Table 6.7 - Recommended restoration options for Reach 26 Option Description Weighted Score Highly Important Measures 5.7g Gravel glides 12.66 Important Measures 5.16 Berm creation 9.14 G3 Targeted maintenance 7.92 5.12 Tree thinning 7.72 5.1m Mill structures - improve operability 7.15 5.13 Deflectors 6.72 5.11 Tree planting 6.46 Less Important Measures None identified

6.3.4 Targeted maintenance Following the principles established in section 6.2.2 the following measures are suggested and may form part of the targeted maintenance protocol being developed for this unit. These include: 1. Silt removal. This is recommended immediately upstream of the Fakenham Mill structures, or where silt deposits will limit discharge at connections with off channel waterbodies. Monitoring and clearance of encroaching silt will be needed within 5m upstream and 10m downstream of each location and 10m upstream of the mill structures. As per the rest of the Wensum this is equal to 1 channel width and 2 channel widths, respectively. 2. Clearance of main channel downstream of confluence with IDB drains. There are no confluences with IDB drains in this reach. However, there is a requirement for inspection and clearance of encroaching marginal vegetation at connections to off channel backwaters. 3. Clearance or realignment of fallen trees blocking channel. Clearance is only required where they are impacting directly on flood risk to property or the structural integrity of third party assets. Fakenham Mill and the road bridge (off Hempton Road) are the only significant structure in this reach, and therefore, the same clearance distances as identified for de-silting apply here. 4. Strategic weed cutting. This is only needed where there is direct threat to houses caused by elevated water levels, or where freeboard is unlikely to be sufficient to receive likely rainfall. Channel conditions downstream of confluences can impact on this, so the sections identified for silt removal need to be inspected for consideration of in-channel weed cutting.

6.3.5 Restoration Measures A number of the restoration measures identified by the MCA have been incorporated into the preferred outline restoration design for Reach 26, which is shown in Figure 6.1. The measures identified are only to be installed if modifications to flow control structures immediately upstream of Fakenham Mill are adopted in order to promote the removal of impoundment in this reach. Of the restoration measures selected for this reach, the highly significant one is: Gravel glides The addition of gravel is beneficial in improving in-channel form and therefore its function. It is expensive, and difficult without good access. Its use is therefore best limited to re-establishing local short raised sections of gravel removed by previous channel works. This will benefit chalk river plants, invertebrates, and fish.

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Figure 6.1 - Conceptual restoration plan for Reach 26 (Fakenham Reach) Unit 47 Tatterford Common to Fakenham Mill_Final.docx 94

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6.4 Reach 27: Hempton Reach This section defines the preferred restoration of Reach 27 by describing key existing features; reviewing the recommended measures as stated in the RWRS; presenting the results of the MCA scoring and detailing rehabilitation measures applied to the reach. 6.4.1 Key existing features influencing proposed restoration measures Table 6.8 presents a brief description of the existing conditions of the reach as observed during the site visit conducted on 13th August 2010. The purpose of the visit was to consider the reach objectives on the ground. Table 6.8 - Significant features and possible measures observed for Reach 27 during site visit

Noted Feature Possible Measure Downstream third of reach is affected by the Lower / remove flow control structures to improve backwater from Fakenham Mill. flow conditions in downstream section of reach. Channel alignment fixed due to road Poor planform in lower third of reach due to infrastructure so coarse adjustment is not channel straightening for Goggs’ Mill and practical. Therefore reliant on easily achievable Fakenham Mill. in-channel features. To become totally effective full flow of the Existing meander loop reconnection. Wensum to be reinstated through loop. Achieved by low-level gravel plug to existing channel. Downstream of the meander loop is heavily Tree thinning to encourage natural narrowing and shaded, especially along the TLHB, limiting use of arisings to provide material for structures marginal macrophyte growth. to promote self-narrowing. Due to impact of nutrient rich river water on Sculthorpe Fen, reinstatement of floodplain Lack of connection with floodplain to TLHB in connectivity would be detrimental to wider upper reaches due to high embankments. conservation interests. The extent of the floodplain to the TRHB is limited and therefore would provide little opportunity. Signs of river narrowing naturally in Promote continued self narrowing adjustment upstream section of reach exacerbating low and augment bed with gravel at selective bed level resulting from historic dredging. locations. Present planform is reasonable; however, Full reinstatement would conflict with wider there is historical evidence of previous conservation aims for the area. However, there channel alignment along the north bank. is scope for a small realignment. For the meander reconnections the downstream No significant off-channel fish refuge habitat section of the existing channel can be left to identified. provide backwaters.

6.4.2 Review of Reach 27 Strategy Objectives Appendix A to the RWRS (JBA, 2007) details a ‘Reach Restoration Strategy’ for each reach. These objectives have been the starting point for the consideration of rehabilitation activities within each reach. A review of these objectives is presented below in Table 6.9.

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Table 6.9 - Review of strategy objectives and recommendations for Reach 27 RWRS Objectives Atkins Comments on the RWRS All works to integrate with lowering of structure at Fakenham Mill and Partially Agree: Backwater does not 1.1 associated river works and must link impact entire length of reach, so works in with the existing enhancement upper section are independent of the mill. schemes. Agree: Channel is certainly over deep and Physically narrow and augment bed with would need gravels adding to provide 1.2 gravels and develop marginal / bankside appropriate bed conditions; self narrowing is vegetation. naturally occurring, so helping with brushwood would be easily achieved. Disagree: Reinstatement of floodplain connectivity in some sections would be Remove embankments to reconnect 1.3 detrimental to wider conservation interests river to its floodplain. due to enriched river water impacting on ground water fed vegetation communities.. Partially agree: Bed does need locally Augment bed on average by 1.0m using raising by 1.0m to improve form and local gravels wherever possible and 2.1 function; Creation of glides needs to fit with create up to 43 gravel glides or riffles in meander pattern suggesting sequence the reach. significantly less than 43. The channel is on average 8.8m over Partially agree: Reach is ungrazed so wide and physical narrowing (with fencing will make no difference; in-channel associated landscaping and fencing) 2.2 works such as brushwood mattresses with may have to be considered to restore selective tree trimming will provide greatest the full functioning of the channel in this variation. reach. Adopt / maintain maintenance regime Agree: The management needed is to and riparian management and allow improve habitat variety not its 2.3 channel to create natural variations in homogenisation caused by weed cutting local channel width and habitat niches. and dredging. Summary Reach 27: Atkins agrees or partially agrees with the majority of principles established by JBA for this reach. The only disagreement relates to embankment removal. This variation is not surprising given the different level of analysis undertaken at the two different stages of the project.

6.4.3 Reach 27: Recommended Restoration This section provides the details of the options and measures proposed for this Reach which have been derived from the Multi-Criteria Analysis (refer to Section 5.3). A summary of the MCA results in their rank order is provided in Table 6.10 and these are further divided into importance according to how far the measure will move the reach towards achieving ‘unfavourable recovering’ or ‘favourable’ ecological condition.

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Table 6.10 - Recommended restoration options for Reach 27 Option Description Weighted Score Highly Important Measures 5.7g Gravel glides 13.46 5.15 Channel re-sectioning 12.07 Important Measures 5.13 Deflectors 10.27 5.16 Berm creation 9.82 5.12 Tree thinning 8.83 5.14 Lower spoil embankments 8.11 G3 Targeted maintenance 7.93 Less Important Measures 5.19 Channel realignment 6.84 5.17 Backwaters – reconnections 6.64 5.1m Mill structures - improve operability 6.42

6.4.4 Targeted maintenance Following the principles established in section 6.2.2 the following measures are suggested and may form part of the targeted maintenance protocol being developed for this unit. These include: 1. Silt removal. This is recommended immediately upstream of structures, or where silt deposits will limit discharge at confluences with IDB drains or significant tributaries. Structures on this reach include Goggs’ Mill road bridge and the Fakenham Bypass road bridge. Monitoring and clearance of encroaching silt will be needed within 5m upstream and 10m downstream of the bridges. As per the rest of the Wensum this is equal to 1 channel width and 2 channel widths respectively. 2. Clearance of main channel downstream of confluence with IDB drains. There are no IDB confluences in this reach. 3. Clearance or realignment of fallen trees blocking channel. Clearance is only required where they are impacting directly on flood risk to property or the structural integrity of third party assets. The only significant structures on this reach are the Goggs’ Mill road bridge and the Fakenham Bypass road bridge, and therefore the same clearance distances as identified for de-silting apply here. Any fallen trees upstream of these bridges need to be considered on their individual merit depending on the proximity of the bridge. 4. Strategic weed cutting. This is only needed where there is direct threat to houses caused by elevated water levels, or where freeboard is unlikely to be sufficient to receive likely rainfall. Neither is considered likely on this reach, and, therefore, no inspection or works are identified.

6.4.5 Restoration Measures All the restoration measures identified by the MCA have been incorporated into the preferred outline restoration design for Reach 27, which is shown in Figure 6.2. Of the restoration measures selected for this reach, the highly significant ones are: Gravel glides The addition of gravel is beneficial in improving in-channel form and therefore its function. It is expensive, and difficult without good access. Its use is therefore best limited to re-establishing local short raised sections of gravel removed by previous channel works. This will benefit chalk river plants, invertebrates, and fish. Channel re-sectioning This is essential to ensure that the relationship between river flow and level is appropriate. The re-sectioning to the upper bank compensates both for less frequent maintenance by increasing the physical channel cross section and by also providing more habitat diversity.

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Figure 6.2 - Conceptual restoration plan for Reach 27 (Hempton Reach)

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6.5 Reach 28: Moor Reach This section defines the preferred restoration of Reach 28 by describing key existing features; reviewing the recommended measures as stated in the RWRS; presenting the results of the MCA scoring and detailing the rehabilitation measures applied to the reach. 6.5.1 Key existing features influencing proposed restoration measures Table 6.11 presents a brief description of the existing conditions of the reach as observed during the site visit conducted on 12th August 2010. The purpose of the visit was to consider the reach objectives on the ground. Table 6.11 - Significant features and possible measures observed for Reach 28 during site visit

Noted Feature Possible Measure Re-meandering and / or re-sectioning would Simplified plan form as channel is wholly provide more visual interest, but present in- artificial for the upstream 2/3. For the channel conditions are within easy reach of downstream 1/3, from the junction with the favourable condition by the simple use of parish boundary, the river follows what is deflectors and shading, thus wholesale likely to be its natural route. realignment would not be cost effective. The 100m downstream of the ford at Sculthorpe Mill has good gradient, bed substrate, and variation in shading. In spite None required. of being a ford it is probably in appropriate condition. The upstream 1/3 of the reach would benefit from The upstream 2/3 has a good gravel bed, slightly higher velocities to improve self cleaning with some silt and a reasonable range of and improved growing conditions for Ranunculus both marginal and aquatic plants. assemblage. This could be achieved through simple deflectors. Low level berms to push the low to medium flows across the channel would aid diversity. With clear felling of the poplars in Moor Plantation, The middle 1/3 of the reach has a hard there is scope for realignment to the TLHB gravel bed, but lacks any degree of variation towards the downstream end of this section. in flow conditions or habitats. There is also scope to realign towards the top of this section, to the TRHB meandering through existing trees, without impacting on the field ditch. The depth of the channel on this reach makes adding in-channel features expensive, so the The downstream 1/3 has been homogenised best option is probably to use brushwood by dredging operations and so is very mattresses to create semi-permeable berms. uniform in plan form and cross section, with These will preferentially trap silt and so improve excessive depth. This has led to it becoming flow velocities adjacent to them as they develop. very silty. There is also the need for gravel glides to provide diversity to the bed material and its height. The downstream 1/3 of the reach is also Fell individual trees into the river to create light substantially shaded due to trees and reed and flow diversity. Trim those trees around the understory. felling to improve light conditions. There is a field ditch running parallel to the The whole reach is single channel, and TRHB. However this is separated by an therefore suffers from lack of fish refuge or embankment, and the incision of the river for the nursery habitat. upper 1/3 of the reach, whilst for the lower 1/3 this ditch becomes an IDB channel with an ill-

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Noted Feature Possible Measure defined link into the river immediately downstream of the reach boundary. The establishment of a connection at the point the IDB channel starts to run parallel with the river, and another 1/2 distance to the existing connection, would create a functioning side channel. If the middle 1/3 of the river were to be realigned to the TRHB, then connections to the parallel field ditch would provide a useful back channel system.

6.5.2 Review of Reach 28 Strategy Objectives Appendix A to the RWRS (JBA, 2007) details a ‘Reach Restoration Strategy’ for each reach. These objectives have been the starting point for the consideration of rehabilitation activities within each reach. A review of these objectives is presented below in Table 6.12.

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Table 6.12 - Review of strategy objectives and recommendations for Reach 28 RWRS Objectives Atkins Comments on the RWRS Partially Agree: Gravel bed through this section would benefit from disruption Use CWD structures to exacerbate caused by deflectors. However, there is 1.1 sinuosity in the wooded area where space for at least 2 meander realignments, channel is straight. with existing alders marking the channel course. Partially agree: The ideal of reconnecting the river and flood plain cannot be readily achieved in this reach due to the depth of Remove embankments to reconnect 1.2 the channel. However, feeding flood water river to its floodplain. from Reach 29 upstream and using the embankments on Reach 28 to control ponding would be beneficial. Partially Agree: The upstream 2/3 does not need gravel; the downstream 1/3 does 1.3 Augment bed with gravel. as the natural bed has been dredged and is being naturally replaced by deep silt. Agree: Channel is self-recovering with Develop marginal / bankside vegetation good bed gravels so natural squeezing 1.4 to encourage channel to narrow would provide energy needed to provide naturally. variation. Partially agree: Poplar wood being clear Potential to use wood from poplar 1.5 felled and removed at time of writing. Other plantations. on site timber may be available for use. Partially agree: The ford and the immediate downstream section have good gradient and unsurprisingly a good gravel No works 100 to 200m downstream of 2.1 bed. Beyond 100m the channel matches Sculthorpe Mill the rest of the section that extends as far as Moor Plantation. Therefore limit only applies to 100m. Partially agree: Upstream 2/3 has good gravel bed, whereas downstream 1/3 does Reduce depth by an average of 0.6m not. Therefore only the lower 1/3 would 2.2 and raise bed using up to 33 gravel benefit. It may need more than 0.6m and glides or riffles in this reach certainly less than 33 glides to better match appropriate geomophological form. Agree: The aim of restoration is to accelerate natural recovery not replace it. So any new works must be appropriate to Assume reach will narrow naturally in this principle, hence tree planting (upstream time. Adopt / maintain maintenance 1/3) or tree trimming (downstream 2/3) to 2.3 regime and riparian management to promote mix of full light, partial shade, and allow channel to naturally narrow. full shading would provide more diverse bed and bank vegetation and would be beneficial for diversity to otherwise rather long uniform sections. Summary Reach 28: Atkins agrees or partially agrees with all the principles established by JBA for this reach. The partial disagreements relate to practical issues associated with the implementation of measures such as embankment removal. This variation is not surprising given the different level of analysis undertaken at the two different stages of the project.

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6.5.3 Reach 28: Recommended Restoration This section provides the details of the options and measures proposed for this reach which have been derived from the Multi-Criteria Analysis (refer to Section 5.3). A summary of the MCA results in their rank order is provided in Table 6.13 and these are further divided into importance according to how far the measure will move the reach towards achieving ‘unfavourable recovering’ or ‘favourable’ ecological condition. Table 6.13 - Recommended restoration options for Reach 28 Option Description Weighted Score Highly Important Measures 5.7g Gravel glides 13.94 Important Measures 5.13 Deflectors 12.46 5.16 Berm creation 11.43 5.12 Tree thinning 10.66 5.19 Channel realignment 10.29 G3 Targeted maintenance 10.17 5.17 Backwaters - reconnections 9.48 5.15 Channel re-sectioning 8.39 5.14 Lower spoil embankments 7.34 5.10 Fencing 6.97 5.18 Backwaters - new 6.46 Less Important Measures 5.11 Tree planting on top of bank 4.82

6.5.4 Targeted maintenance Following the principles established in section 6.2.2 the following measures are suggested and may form part of the targeted maintenance protocol being developed for this unit. These include: 1. Silt removal. This is recommended immediately upstream of structures, or where silt deposits will limit discharge at confluences with IDB drains or significant tributaries. There are no structures on this reach. Conceptual designs to connect to the IDB drain discharging upstream of Gogg’s Mill Road bridge may result in the need for inspection and silt removal works in this reach. 2. Clearance of main channel downstream of confluence with IDB drains. There are none on this reach, so there is no requirement for this type of work. This will be a requirement if the proposed reconnections are implemented. 3. Clearance or realignment of fallen trees blocking channel. Clearance is only required where they are impacting directly on flood risk to property or the structural integrity of third party assets. There are no structures nor IDB connections on this reach therefore no inspection or works identified for this reach. But see comments above. 4. Strategic weed cutting. This is only needed where there is direct threat to houses caused by elevated water levels, or where freeboard is unlikely to be sufficient to receive likely rainfall. Neither is considered likely on this reach, and therefore, no inspection or works are identified.

6.5.5 Restoration Measures The majority of restoration measures identified by the MCA have been incorporated into the preferred outline restoration design for Reach 28. The exception is new backwaters, which may be achieved through use of existing channel lengths in realigned sections. However, this is dependent on spoil volumes generated on site. The proposed conceptual design is shown in Figure 6.3. Of the restoration measures selected for this reach, the highly significant one is:

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Gravel glides The addition of gravel is beneficial in improving in-channel form and therefore its function. It is expensive, and difficult without good access for machinery. Its use is therefore best limited to re- establishing local short raised sections of gravel removed by previous channel works. This will benefit chalk river plants, invertebrates, and fish.

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Figure 6.3 - Conceptual restoration plan for Reach 28 (Moor Reach) Unit 47 Tatterford Common to Fakenham Mill_Final.docx 104

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6.6 Reach 29: Shereford Reach This section defines the preferred restoration of Reach 29 by describing key existing features; reviewing the recommended measures as stated in the RWRS; presenting the results of the MCA scoring and detailing the rehabilitation measures applied to the reach. 6.6.1 Key existing features influencing proposed restoration measures Table 6.14 presents a brief description of the existing conditions of the reach as observed during the site visit conducted on 11th and 12th August 2010. The purpose of the visit was to consider the reach objectives on the ground. Table 6.14 - Significant features and possible measures observed for Reach 29 during site visit

Noted Feature Possible Measure For the downstream 1/2 simple in-channel The planform for the downstream 1/2 of the features such as berms or deflections will reach is reasonable; for the upstream 1/2 it increase sinuosity. For the upstream 1/2 channel appears more simplified with channel realignment would be more appropriate to straightening obvious either side of improve sinuosity to the amount expected of a Doughton Bridge. chalk river in its upper catchment. From Manor Farm to about 100m upstream of Doughton Bridge the river is ponded with little velocity apparent. Raise bed level in upstream sections through Examination of the 1993 survey shows that a gravel placement to improve gradient and 200m length of river, mostly parallel with the effectively remove impoundment created by more road, is significantly above the gradient line. natural bed section downstream of Manor Farm. There is also a further 100m downstream Alternatively, lower bed in more natural section, and 250m upstream which is also slightly although due the presence of existing good above the gradient line. The ponding habitat in this area the recommendation is to observed is a result of the removal of bed protect and enhance. material upstream of these more natural sections. There is significant shading from trees to the Selective tree trimming and / or felling would north bank from the old bridge at Manor improve the balance of light and shade through Farm to Doughton Bridge. this section. Good gradient due to straight alignment probably The upstream 475m of the reach has good achieves the critical velocities. If flows are varied bed topography and gravelly bed. restricted, low level berms would maintain velocity, but generally does not need restoration. The river downstream of 475m is more Removal of the causes of backwater effect would uniform with water depths deeper and more help improve effectiveness of any local bed natural berm development due to self raising or berms to re-energise the flow for this adjustment of the over widened and over section. deepened cross section.

6.6.2 Review of Reach 29 Strategy Objectives Appendix A to the RWRS (JBA, 2007) details a ‘Reach Restoration Strategy’ for each reach. These objectives have been the starting point for the consideration of rehabilitation activities within each reach. A review of these objectives is presented below in Table 6.15.

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Table 6.15 - Review of strategy objectives and recommendations for Reach 29 RWRS Objectives Atkins Comments on the RWRS Disagree: With the removal of the boards All works to integrate with lowering of at the mill, the residual drop through the 1.1 structure at Sculthorpe Mill and structure is slight, and so it is difficult to associated river works. justify further works. Partially agree: De-silting is not required, as channel is naturally readjusting and De-silt channel just upstream of exposing gravel. Artificial de-silting is likely 1.2 Sculthorpe Mill, physically narrow and to remove both silt and gravel. Planform augment bed with gravels and cross-section are uniform so we agree that narrowing works would assist in diversity. Remove scrub to open up the channel Agree: There are sections of dense 1.3 and encourage development of marginal shading which could be usefully broken up / bankside vegetation. into smaller lengths to provide diversity. Use of CWD structures to ‘exacerbate’ Partially Agree: CWD would help sinuosity 1.4 sinuosity in the wooded area where on straight sections, providing water levels channel is straight. were lowered, as it is presently too deep. Initial work required is for bed and bank Disagree: The removal of the boards at the stabilisation associated with lowering of 2.1 mill has shown that silt is self stable, and Sculthorpe Mill structures at the that the banks are naturally stable. downstream end of reach. Disagree: Change in flow regime due to Appropriate measures required to removal of the boards at the mill has shown 2.2 manage silt deposits upstream of the that the river is self managing the silts mill. without apparent detriment downstream of the mill. Augment bed on average by 0.5m using Partially Agree: Reach would benefit from local gravels wherever possible and replacement of gravel in form of glides. 2.3 create up to 70 gravel glides or riffles in This would be achieved with significantly the reach. less than 70. The channel is on average 9.1m over Partially Agree: The channel is over-wide, wide and physically narrowing (with but with self-narrowing occurring, the stated associated landscaping and fencing) 2.4 figures seem an over estimate. Very few of may have to be considered to restore the riverside fields are grazed so fencing is the full functioning of the channel in this unlikely to make a significant difference. reach following works at Sculthorpe Mill. Agree: Reach is subject to weed cutting which leads to synchronicity of plant growth Adopt / maintain maintenance regime and distortion of species proportions, both and riparian management to allow of which add to flow resistance. The use of 2.5 channel to create natural variations in boards at Sculthorpe Mill to raise water local channel width and habitat niches. levels to allow weed boat access has led to excessive siltation and degraded river conditions. Agree: Post-project monitoring is needed Post-project monitoring is required, to confirm changes are as expected and 2.6 especially in association with works at beneficial. This will allow earlier, small and the mill structure therefore less intrusive intervention. Summary Reach 29: Atkins agrees or partially agrees with over half of the principles established by JBA for this reach. The disagreements relate to recent observations following board removal at Sculthorpe Mill.

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6.6.3 Reach 29: Recommended Restoration This section provides the details of the options and measures proposed for this reach which have been derived from the Multi-Criteria Analysis (refer to Section 5.3). A summary of the MCA results in their rank order is provided in Table 6.16 and these are further divided into importance according to how far the measure will move the reach towards achieving ‘unfavourable recovering’ or ‘favourable’ ecological condition. Table 6.16 - Recommended restoration options for Reach 29 Option Description Weighted Score Highly Important Measures 5.7g Gravel glides 13.93 Important Measures 5.15 Channel re-sectioning 12.03 5.12 Tree thinning 11.56 5.16 Berm creation 11.53 5.13 Deflectors 11.22 5.19 Channel realignment 10.29 5.17 Backwater - reconnections 9.83 5.2m Mill structures – remove flow control mechanisms 9.26 5.14 Lower spoil embankments 7.17 G3 Targeted maintenance 7.02 Less Important Measures 5.10 Fencing 6.96 5.11 Tree planting 6.62

6.6.4 Targeted maintenance Following the principles established in section 6.2.2 the following measures are suggested and may form part of the targeted maintenance protocol being developed for this unit. These include: 1. Silt removal. This is recommended immediately upstream of structures, or where silt deposits will limit discharge at confluences with IDB drains or significant tributaries. Doughton Bridge and Sculthorpe Mill are the only significant structures in this reach. Monitoring and clearance of encroaching silt will be needed within 5m upstream and 10m downstream of this bridge and 10 upstream of the mill. 2. Clearance of main channel downstream of confluence with IDB drains. There is one on this reach at Sculthorpe Mill. This is in the vicinity of the ford and so clearance works are unlikely to be needed due to disturbance at the ford. 3. Clearance or realignment of fallen trees blocking channel. Doughton Bridge and Sculthorpe Mill are the only significant structures on this reach. Any fallen trees upstream of these structures need to be considered on their individual merit depending on the proximity to the structure. 4. Strategic weed cutting. This is only needed where there is direct threat to houses caused by elevated water levels, or where freeboard is unlikely to be sufficient to receive likely rainfall. Inspection or works are identified for this reach at Doughton Bridge and Sculthorpe Mill.

6.6.5 Restoration Measures The majority of the restoration measures identified by the MCA have been incorporated into the preferred outline restoration design for Reach 29, which is shown in Figure 6.4. Of the restoration measures selected for this reach, the highly important one is gravel glides: Gravel glides The addition of gravel glides downstream of Shereford is recommended as a bed raising measure to bring about the required improvement in gradient upstream of the more natural channel grade Unit 47 Tatterford Common to Fakenham Mill_Final.docx 107

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identified. Gradient recovery will reduce the ponding created by the over-deepening which has occurred upstream of Manor Farm whilst also improving in-channel form and function to benefit chalk river plants, invertebrates, and fish. Creation of free-flowing conditions within the currently ponded section will improve flow conveyance and the suitability of the reach for incorporation of the additional measures identified. An alternative approach to upstream bed raising would be to lower the bed in the more natural sections to match the gradient upstream. However, bed lowering is likely to reduce connectivity between the river and floodplain and the presence of existing good habitat in the more natural sections lend support to a protect and enhance approach.

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Figure 6.4 - Conceptual restoration plan for Reach 29 (Shereford Reach)

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6.7 Reach 30: South Mill Reach This section defines the preferred restoration of Reach 30 by describing key existing features; reviewing the recommended measures as stated in the RWRS; presenting the results of the MCA scoring and detailing the rehabilitation measures applied to the reach. 6.7.1 Key existing features influencing proposed restoration measures Table 6.17 presents a brief description of the existing conditions of the reach as observed during the site visit conducted on 11th August 2010. The purpose of the visit was to consider the reach objectives on the ground. Table 6.17 - Significant features and possible measures observed for Reach 30 during site visit

Noted Feature Possible Measure The upstream 1/2 of the reach appears to The vegetation is sufficiently vigorous and the have little gradient and is severely choked by gradient flat enough that clearance and stream emergent vegetation (Sparganium erectum). modifications are unlikely to work. By-passing it There is no sinuosity. would seem to be a more reliable choice. The downstream 1/2 appears to have better The use of deflectors or berms to re-energise gradient and some sinuosity. flow would also improve sinuosity. The ditch across the field on the west bank Partially re-create the old river alignment utilising and bounded by the river to the east and the upstream 1/2 of the field ditch, and create a south has good planform and may represent new meandering channel along the minor field the old river course prior to the construction drain to connect with the existing river channel of South Mill. about 80m upstream of Southmill Farm. There appears to be little or no backwater None required. effect due to South Mill sill. Some tree thinning and re-use of the arisings for Some shading at the very upstream end. in-channel deflectors would improve diversity.

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6.7.2 Review of Reach 30 Strategy Objectives Appendix A to the RWRS (JBA, 2007) details a ‘Reach Restoration Strategy’ for each reach. These objectives have been the starting point for the consideration of rehabilitation activities within each reach. A review of these objectives is presented below in Table 6.18. Table 6.18 - Review of strategy objectives and recommendations

RWRS Objectives Atkins Comments on the RWRS All works must integrate with removal of Disagree: The sill makes no discernable 1.1 sill-type structure at South Mill and any difference to flows in the location (there is associated river works. no backwater effect). Partially Agree: The reinstatement of an appropriately meandering channel would Reinstate meandering channel with overcome the issues with the flat choked appropriate sinuosity and fill in the 1.2 section of the reach. However the existing existing channel that was created as a channel can be used as a nursery side diversion when South Mill was in use. channel, and for flood flows, so disagree about in-filling it. Partially Agree: More opportunities are associated with the proposed route which follows the low point of the flood plain. Also It would be suitable to reconnect the the channel immediately upstream of South 1.3 restoration channel with the existing Mill is in reasonable condition. A better channel at the road bridge by South Mill. answer is to use some of the field channel and cut across the field upstream of South Mill. Agree: Planting or trimming of trees would Develop marginal / bankside vegetation, 1.4 improve variation in both the bankside and with some riparian trees. marginal vegetation. Agree: Existing river is single channel Connect to drains or create off-river 1.5 without connections to the other refuges. watercourses in the reach. Agree: Changes would significantly 2.1 Restore section of channel. improve 1/2 the reach and develop the other 1/2. Summary Reach 30: Atkins agrees or partially agrees with all but one of the principles established by JBA for this reach. The only disagreements are over the details, such as the removal of South Mill sill where a more detailed site examination has allowed a more accurate assessment to be made. This variation is not surprising given the different level of analysis undertaken at the two different stages of the project.

6.7.3 Reach 30: Recommended Restoration This section provides the details of the options and measures proposed for this reach which have been derived from the Multi-Criteria Analysis (refer to Section 5.3). A summary of the MCA results in their rank order is provided in Table 6.19 and these are further divided into importance according to how far the measure will move the reach towards achieving ‘unfavourable recovering’ or ‘favourable’ ecological condition.

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Table 6.19 - Recommended restoration options for Reach 30 Option Description Weighted Score Highly Important Measures 5.19 Channel realignment 12.16 5.7g Gravel glides 11.77 Important Measures 5.16 Berm creation 10.43 5.17 Backwaters – reconnections 9.64 5.10 Fencing 8.16 5.13 Deflectors 7.62 5.11 Tree planting 7.07 Less Important Measures 5.15 Channel re-sectioning 6.22 G3 Targeted maintenance 5.86

6.7.4 Targeted maintenance Following the principles established in section 6.2.2 the following measures are suggested and may form part of the targeted maintenance protocol being developed for this unit. These include: 1. Silt removal. This is recommended immediately upstream of structures. There is one on this reach, the road bridge at Southmill Farm so monitoring and clearance of encroaching silt will be needed within 5m upstream of the bridge (equal to 1 channel width) and 10m downstream (equal to 2 channel widths). 2. Clearance of main channel downstream of confluence with IDB drains. Although there are none on this reach, key field drain confluences are identified where appropriate management may be required. 3. Clearance or realignment of fallen trees blocking channel. Clearance is only required where they are impacting directly on flood risk to property or the structural integrity of third party assets. The only significant structure is the road bridge at Southmill Farm. A few trees are present upstream of the bridge so monitoring is required. 4. Strategic weed cutting. This is only needed where there is direct threat to houses caused by elevated water levels, or where freeboard is unlikely to be sufficient to receive likely rainfall.

6.7.5 Restoration Measures All the restoration measures identified by the MCA have been incorporated into the preferred outline restoration design for Reach 30, which is shown in Figure 6.5. Of the restoration measures selected for this reach, the highly important ones are: Channel realignment As the existing channel has been extensively modified, resulting in reduced gradient, the only way to improve flow character is to realign the channel so that it has a greater natural gradient. In this case a realignment incorporating existing field drains which joins the existing channel 100m upstream of Southmill Farm provides the required increase in gradient. Gravel glides The addition of gravel is beneficial in improving in-channel form and therefore its function. It is expensive, and difficult without good access for machinery. Its use is therefore best limited to re- establishing local short raised sections of gravel removed by previous channel works. This will benefit chalk river plants, invertebrates, and fish.

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Figure 6.5 - Conceptual restoration plan for Reach 30 (South Mill Reach) Unit 47 Tatterford Common to Fakenham Mill_Final.docx 113

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6.8 Reach 31: Confluence Reach This section defines the preferred restoration of Reach 31 by describing key existing features; reviewing the recommended measures as stated in the RWRS; presenting the results of the MCA scoring and detailing the rehabilitation measures applied to the reach. 6.8.1 Key existing features influencing proposed restoration measures Table 6.20 presents a brief description of the existing conditions of the reach as observed during the site visit conducted on 11th August 2010. The purpose of the visit was to consider the reach objectives on the ground. Table 6.20 - Significant features and possible measures observed for Reach 31 during site visit

Noted Feature Possible Measure Good appropriate planform. None required. Targeted maintenance required at confluence of Good gravels downstream of confluence with Tat to remove silt and excessive encroaching River Tat. vegetation. Care will be required to leave the gravel bed undisturbed. Provide fencing, and cattle drink if necessary, to Lack of fencing allows livestock down into allow bankside vegetation to grow. This will help the river. control poaching. Cattle drink on the Tat immediately upstream Line the cattle drink with gravel to minimise bed of the confluence is releasing sediment into erosion and silt mobilisation. the Wensum. Main river finishes at the confluence of the Tat and Wensum. Upstream of the Treatments cover whole reach as will benefit confluence the Wensum is an IDB Main main river. Drain.

6.8.2 Review of Reach 31 Strategy Objectives Appendix A to the RWRS (JBA, 2007) details a ‘Reach Restoration Strategy’ for each reach. These objectives have been the starting point for the consideration of rehabilitation activities within each reach. A review of these objectives is presented below in Table 6.21.

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Table 6.21 - Review of strategy objectives and recommendations RWRS Objectives Atkins Comments on the RWRS Encourage less extensive stocking of livestock and develop marginal / Agree: Could achieve the same effect with 1.1 bankside vegetation. Allow to narrow fencing. naturally. Disagree: No significant embankments Remove embankments to reconnect the seen in the near vicinity of the river and 1.2 river to its floodplain. therefore little likely effect in terms of floodplain connection. Adopt / maintain maintenance regime Agree: There is a good gross planform and riparian management to allow which will be enhanced by natural self channel to develop a more natural form. 2.1 adjustment. This will be achieved by However, assume reach will narrow exclusion of livestock and closely specified naturally in time and that no bed raising targeted maintenance. is required. Summary Reach 31: Atkins agrees with all the principles established by JBA regarding riparian management for this reach. The only disagreement is regarding alteration of the river, in this case embankment removal where we believe it would be of negligible benefit. This variation is not surprising given the different level of analysis undertaken at the two different stages of the project.

6.8.3 Reach 31: Recommended Restoration This section provides the details of the options and measures proposed for this reach which have been derived from the Multi-Criteria Analysis (refer to Section 5.3). A summary of the MCA results in their rank order is provided in Table 6.22 and these are further divided into importance according to how far the measure will move the reach towards achieving ‘unfavourable recovering’ or ‘favourable’ ecological condition. Table 6.22 - Recommended restoration options for Reach 31 Option Description Weighted Score Highly Important Measures 5.10 Fencing 11.66 5.16 Berm creation 9.42 Important Measures 5.13 Deflector 8.21 5.14 Lower spoil embankments 7.00 5.12 Tree thinning 6.16 5.8g Gravel glides 6.06 5.11 Tree planting 5.71 G3 Targeted maintenance 4.12 Less Important Measures 5.15 Channel re-sectioning 3.91 5.18 Backwaters - new 3.09

6.8.4 Targeted maintenance Following the principles established in section 6.2.2 the following measures are suggested and may form part of the targeted maintenance protocol being developed for this unit. These include: 1. Silt removal. There are no structures in this reach so there is no requirement for this type of work.

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2. Clearance of main channel downstream of confluence with IDB drains. The River Wensum in the upper part of this reach is classified as IDB Main River. This reach contains the confluence with the River Tat so clearance needs to be considered in this location. 3. Clearance or realignment of fallen trees blocking channel. Clearance is only required where they are impacting directly on flood risk to property or the structural integrity of third party assets. These risks are not considered relevant to this reach. 4. Strategic weed cutting. This is only needed where there is direct threat to houses caused by elevated water levels, or where freeboard is unlikely to be sufficient to receive likely rainfall. This is not considered to be relevant to this reach.

6.8.5 Restoration Measures Due to the existing good planform it is anticipated that natural self adjustments will, in time, provided betterment to the condition of this reach. Such adjustments are evident downstream of the confluence of the River Tat where natural narrowing through berm development has occurred. As such the implementation of the highly important measure, fencing, to exclude the detrimental effects of intensive livestock grazing and poaching is included in the conceptual design as the main measure to ‘kick-start’ the process. Once the channel has adjusted to the exclusion of livestock the suitability of the other measures identified through the MCA can be determined.

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Figure 6.6 - Conceptual restoration plan for Reach 31 (Confluence Reach) Unit 47 Tatterford Common to Fakenham Mill_Final.docx 117

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7. Cost Estimate

This chapter covers the cost estimate for delivering the preferred restoration options/measures for each reach as outlined in Chapter 6. To set this in context, a brief background history of previous published reports and their cost estimates is summarised in Section 7.1. Current estimates for Reaches 26 to 31 following the MCA analysis and concept design are presented in Section 7.2 together with the main assumptions for the estimates. Potential cost savings are presented in Section 7.3 and delivery or phasing aspects are detailed in Section 7.4. 7.1 Previous cost estimates

7.1.1 Background Two previous reports, the RWRS (JBA, 2007) and Estimating Costs of Delivering the River Restoration Element of the SSSI Target (Halcrow, 2008a), included some costs for restoration options on the river. The JBA RWRS report provided costs per kilometre of in-channel river works including bed raising, channel narrowing and restoring meanders. Based on these rates and the recommendations in the report for Unit 47, this equates to the costs outlined in Table 7.1. Table 7.1 - RWRS Unit 47 cost estimate (JBA, 2007)

Reach 26 27 28 29 30 31 Reach length: m 464 1720 1245 2630 665 475 Length of recommended works: 0.464 1.72 1.245 2.63 0.5 0.475 km Restoration £- £75,000 £- Narrowing <10 m £344,000 £526,000 £- £- Narrowing >10 m £185,600 £- £- £- Bed raising £83,520 £309,600 £224,100 £473,400 £- £- Landscaping £464 £1,720 £2,630 £475 Fencing £2,784 £10,320 £18,780 £2,850 Modification of mill £500,000 structures Total for reach: £772,368 £665,640 £224,100 £1,017,810 £75,000 £3,325 Total for Unit 47: £ 2,758,243 Note: Estimates of total river restoration and rehabilitation assumed from JBA 2007 Technical Report Appendix A.

The Halcrow 2008a report covers all river SSSIs in England and includes the prevailing views of Natural England and the Environment Agency regarding appropriate measures for each unit on each river. A summary of the Halcrow costs for Unit 47 are presented in Table 7.2.

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Table 7.2 - Halcrow PSA Unit 47 cost estimate

Unit 47 Fencing Fencing LWD Structures In-stream Section Cross Modifications Bed Raising Structure Meandering % length requiring 0.0% 5.0% 5.0% 30.0% 30.0% 60.0% 0.0% work Length in km £- 0.36 0.36 2.16 2.16 4.32 £- requiring work Total cost per £- £19,447 £80,567 £59,731 £153,725 £162,986 £- km/length Cost per unit per £- £7,000 £29,000 £129,000 £332,000 £704,000 £- activity £ Total for Unit: £1,201,000

A comparison of JBA and Halcrow cost estimates are presented in Table 7.3. This shows that the cost estimates to restore Unit 47 of the River Wensum range between £2,758,243 and £1,201,000. This feasibility report has looked at all options for restoration in more detail and hence it is appropriate that the costs for the recommended options are refined further. Table 7.3 - Comparison of cost estimates between JBA and Halcrow reports for Unit 47

Unit 47 LWD In-stream Structures Cross Section Modifications Raising Bed Restoration Structure Modification

RWRS £- £- £1,055,600 1,090,620 £112,023 £500,000

SSSI Cost £7,000 £29,000 £129,000 £ 332,000 £- £704,000 Estimates

7.2 Present cost estimates

7.2.1 Unit 47 Cost Estimate Costs for implementing the recommended options and measures for the whole of SSSI Unit 47 have been estimated based on information from the RWRS (JBA, 2007), SSSI Estimated Costs Report (Halcrow, 2008a) and other sources. Making use of previous cost estimates where appropriate has ensured consistency in the cost estimates so that the feasibility report provides a refined cost estimate rather than an independent one. Table 7.4 shows the revised total cost estimate for the different river restoration measures recommended for Unit 47. This estimate is based on a number of assumptions relating to sizes, quantities, materials and conditions. It also reflects current prices and costs which may have changed since the JBA and Halcrow reports were carried out. The targeted maintenance option has not been costed due to uncertainty in rates. This exclusion, along with the assumptions, will affect the accuracy of the final cost estimate. The full details of the costs and assumptions are given in Appendix B. Unit 47 Tatterford Common to Fakenham Mill_Final.docx 119

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Table 7.4 - Unit 47 cost estimates for various river restoration measures

Total Option / Measure Description Quantity Rate / Unit Cost

5.10 Fencing (m) 7,210 4 £28,840 5.16 Berm creation (m) 672 90 £60,480 5.15 Channel re-sectioning (m3) 125.73 14.18 £1,783 5.12 Tree felling (m) 970 10 £9,700 5.17 Backchannel – reconnection (m3) 1,965.3 14.18 £27,868 5.7g Gravel glides (m3) 3,570.4 53 £189,231 5.19 Channel realignment (m3) 1,901.8 9.83 £18,694 5.13 Deflector (m) 130 44 £5,720 5.11 Tree planting (unit) 140 58 £8,120 - Plugs (m3) 939.2 53 £ 49,777 5.30 Mill structure £- 5.14 Lower spoil embankments (m3) 300 9.83 £2,949 G3 Targeted maintenance Unknown TOTAL COST £403,162

Table 7.5 shows the cost estimates for each reach and restoration measures. Table 7.5 – Unit 47 cost estimates for each reach and restoration measure Description 26 27 28 29 30 31 Fencing £- £6,880 £ 4,980 £10,520 £2,660 £3,800 Berm creation £34,020 £5,670 £ 20,790 £- £- £- Channel re- £- £- £1,783 £- £- £- sectioning Tree felling £1,100 £ 2,000 £5,600 £- £1,000 £- Backchannel – £- £15,813 £5,930 £6,126 £- £- reconnection Gravel glides £67,662 £87,099 £14,000 £12,766 £7,705 £- Channel £- £- £8,644 £- £10,050 £- realignment Deflector £- £2,332 £2,772 £- £616 £- Tree planting £- £2,320 £- £- £2,900 £2,900 Plugs £- £29,999 £- £- £19,778 Targeted unknown unknown unknown unknown unknown unknown Maintenance Lower spoil £- £2,949 £- £- £- £- embankments Reach Totals £102,782 £155,062 £64,499 £29,412 £44,709 £ 6,700 Note: Reach totals containing rounding error. 7.3 Potential cost savings The total cost estimate of £403,162 for Unit 47 is based on a number of assumptions, in particular the materials and installation methods for the various recommended river restoration measures (see Appendix B for further details). Should alternative restoration measures be implemented, this may affect the total price outcome. Efficiency savings could be achieved by re-using, where appropriate, spoil generated as part of the restoration works to construct features that require spoil. The following section identifies potential means of reducing costs associated with spoil disposal.

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7.3.1 Spoil Reduction A number of the river restoration measures for Unit 47 generate spoil as outlined in Table 7.6. Table 7.6 - Options that typically generate or require spoil

Reach: Spoil 26 27 28 29 30 31 Total Generation (m3) Berms -3,258 -540 -1,934 -5,732 (need spoil) Re-sectioning 126 126 (generate spoil) Backchannel reconnections and 1,115 418 432 1,965 creation (generate spoil) Channel realignment 879 1,022 1,901 (generate spoil) Lowering spoil embankments 300 300 (generate spoil) Total surplus spoil -3,258 875 -511 432 1022 0 -1,440 (m3): Applicable but limited. Opportunity to Not Applicable Not Applicable Not Can use applicable but limited applicable but limited applicable reduce spoil. or lose spoil on site. Note: A negative number indicates a measure that requires spoil

Table 7.6 shows there is no net surplus spoil volume for the whole unit. Whilst at a reach scale, Reaches 27, 29 and 30 generate additional spoil. It is assumed that this can be lost on site. Any reduction in spoil disposal will reduce the amount of trafficking on site to dispose of the material. Opportunities to reduce spoil generation and movement should be sought during the detailed planning and construction phases. This will have beneficial consequences in terms of:  Reduced land take;  Reduced cost  Reduced carbon footprint;  Reduced grounds for landowner dissatisfaction; and  Reduced need for environmental mitigation. For the channel realignment and new backchannels connections excavation lengths cannot be meaningfully reduced as they need to maintain recommended size and to provide long term stability. 7.3.2 Gravel Glides The MCA identified that the most beneficial measure of reintroducing gravel to the system was in the form of gravel glides which have been recommended for Reaches 26, 27, 28 and 30. Gravel glides account for the highest percentage (47%) of the total option costs, a total estimate of £189,231. There are two alternative methods of reducing gravel glide costs:

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 Replacing the gravel in the bottom 2/3 of the glide with inert fill (depth substitution), or  Replacing the downstream 2/3 with transverse hurdles to trap silt and so use deposition to create tail of the glide (length substitution). Depth substitution: Surplus spoil has to be disposed of so could be used in part to substitute for two thirds of the gravel volume to the gravel glides. The reduction in costs comes from the reduction in volume of gravel used as presented in Table 7.7. Table 7.7 - Gravel substitution using surplus fill

Reach Surplus No. Opportunity to Volume of Total Spoil Glides in Substitute Gravel with gravel replaced Volumes Volume Reach Excess Spoil by spoil per Saved glide (2/3 of total glide volume) 26 -3258 9 No- no spoil 27 875 12 Yes 94.6 875* 28 -511 8 No - no spoil 29 432 6 Yes 26.7 160 30 1022 7 Yes 13.7 96 31 0 0 No Total measure: 1,131 Gravel cost £/m3: 53 Spoil disposal cost £/m3: 4.81 Potential gravel cost saving £59,943 Potential spoil disposal cost saving £5,440 Total cost of glides including cost saving £123,848 Original gravel glide cost £189,231

Note: * indicates that all excess spoil is utilised

The total achievable cost savings associated with reducing gravel requirement through spoil utilisation in gravel glides is as follows:  A reduction in gravel costs of £59,943 combined with a spoil reduction cost of £5,440 represents a saving of 35% on the total gravel glide cost or 16% on the total implementation cost for Unit 47. Length substitution: As designed, the gravel glides are nominally three times the resistant channel width. This gives a glide length of one half of the bend length based on erodible river width. This is a reasonable compromise in terms of glide length when compared to existing gross channel shape and the smaller self-narrowing variations. Cost savings could be made by replacing some of the gravel with other materials. For example, the first one third of the glide could be made of gravel, but the remainder comprises two cross- river hurdles spaced at a natural channel width to trap silt and infill downstream of the gravel. Changing the material and arrangement in this way could represent cost savings, as shown in Table 7.8. However, substituting sections of the gravel glides with hurdles is only possible if the river bed system has a mobile gravel bed and gravel supply. The opportunity to reduce the cost by this means will therefore need to be assessed. Monitoring work at Bintree should inform the success of this technique over time and these results should be considered in future stages of the strategy.

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Table 7.8 – Revised costs for gravel glides with length substitution Reach No. 1/3 Volume Total Hurdles Total Width Total Glides per Glide Volume (m3) Width per of hurdle (m3) Glide (m) per reach (m)

26 9 47.3 425.7 6.8 122 27 12 45.6 547.2 6.7 161 28 8 11 88 6.35 102 29 6 13.4 80.4 6.2 74 30 7 6.9 48.3 3.55 50 31 0 0 0 0 0 Total measure: 1,190 509 Rate in £/per unit: 53 133 Total cost £63,070 £52,427 Total cost with length substitution £115,497 Original cost £189,231

The total cost for constructing gravel glides using length substitution of gravel glides amounts to £115,497 which represents a saving of 39% of the total gravel glide costs for the unit or 18% of the total restoration implementation cost for Unit 47. This is a significant reduction in cost. 7.3.3 Cost Saving Summary: There are opportunities to make significant savings through replacing part of the gravel glide material through depth substitution which is considered to be the most appropriate method for this unit. Should depth substitution be implemented, this could reduce the total restoration cost to £337,779. This gives a total cost saving of 16% compared to the initial cost estimate. 7.4 Delivery Section 7.3 provides details of the costs for physical works, but this can be influenced by how the works are carried out. The following sections explore this further. Phasing: The phasing of the excavation measures can reduce the amount of double handling needed. This has benefits in reducing the amount of physical work required, and therefore:  Unnecessary disturbance and damage to the environment.  Less disruption risk due to bad weather or poor ground conditions.  Reduction of scheme costs. It is recommended the works be phased in the order listed in Table 7.9.

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Table 7.9 - Recommended phasing of work

Measure Reason for Phased Order Provides flood risk management, silt control and 1 Targeted maintenance confirms Environment Agency presence on the river.

Highly important for project delivery, immediately 2 Back channel reconnection helps with fish recruitment and flood risk, and generates large volumes of spoil. Facilitates access to the river and generates spoil 3 Lower spoil embankments for used in other restoration measures.

Must follow spoil removal to access the river banks, 4 Berm creation the two previous operations will generate the arisings with which to complete berm creation. The impact of berms on flow and level can be 5 Re-sectioning assessed and so inform the required re-section depth.

Previous measures have improved in-channel 6 Tree thinning conditions to allow macrophyte growth, and so tree thinning is now required to remove shade.

Tree thinning and felling provides raw material for 7 Deflectors the deflectors, and re-sectioning has improved channel capacity. The impact of berms and deflectors on flow 8 Realignment patterns can be assessed to inform the extent to which realignment is needed. With all previous in-channel works, and any silt release completed, smaller gravel works can be 9 Gravel glides placed in the channel at the best locations and shaped for maximum impact.

With all the in-river features in place the location for 10 Tree planting the trees can be easily seen, and without further works the trees are unlikely to be damaged. If this is not done last, any further works will require 11 Fencing its removal and re-construction.

7.4.1 Monitoring The details for river monitoring need to be agreed between Natural England and the Environment Agency before any restoration measures commence on site. Monitoring will have to commence before restoration works start to collect baseline data. Monitoring will also allow a comparison of changes to be recorded as each phase is implemented. 7.4.2 Maintenance If there are time gaps between implementing different restoration measures, then ‘Targeted Maintenance’ will help manage the river appropriately until works can commence. 7.4.3 Local resources If the implementation of the works is to be phased geographically, then there is merit in including the landowners in the tendering list, as they may have the necessary resources to complete the

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excavation and spoil movement and spreading. This would bring unrivalled local knowledge to bear on each river reach subsection, and would open-up opportunities that other contractors would not be able to realise. 7.5 Summary Table 7.10 summarises the recommended restoration measures, in order of phasing, for Unit 47. It is interesting to note the changes in ranking that occur due to the larger-scale. Table 7.10 Recommended phasing of restoration measures for Unit 47

Options Measure Phasing MCA Score 26 27 28 29 30 31 Mean ‘Targeted G3 1 7.92 7.93 10.17 7.02 5.86 4.12 7.17 maintenance’ Backchannel 5.17 2 0 6.64 9.48 9.83 9.64 -0.79 5.80 reconnection Lower spoil 5.14 3 0 8.11 7.34 7.17 0 7.00 3.77 embankments

5.16 Berm creation 4 9.14 9.82 11.43 11.53 10.43 9.42 10.30

5.15 Re-sectioning 5 0 12.07 8.39 12.03 6.22 3.91 7.10

5.12 Tree thinning 6 7.72 8.83 10.66 11.56 5.36 6.16 8.38

5.13 Deflectors 7 6.72 10.27 12.46 11.22 7.62 8.21 9.42

5.19 Re-alignment 8 0 6.84 10.29 10.29 12.16 0 6.60

5.7g Gravel glides 9 12.66 13.46 13.94 13.93 11.77 6.06 11.97

5.11 Tree planting 10 6.46 6.08 4.82 6.62 7.07 5.71 6.13

5.10 Fencing 11 0 6.42 6.97 6.96 8.16 11.66 7.33 Mean 4.60 8.77 9.63 9.83 7.66 5.59 Highly important >9.45 >11.01 >13 >12.08 >10.88 >9.04 Less important <4.99 <5.08 <5.73 <6.73 <5.98 <4.03

This demonstrates why analysis should be carried out at the reach level and the results aggregated or up-scaled to unit level, rather than studied at the unit level and downscaled to the reach level. The key points to note are:  the phasing relates to the order of installation, not to the order of importance in delivering the changes in form and process to the main river channel;  the scores derived from the MCA provide the method for placing each measure in relation to each other measure to give the combined final design that provides the best delivery in the long-term;  the design for each reach is related to the conditions within the unit and takes account of the changes in other reaches that have inter-reach impacts, such as mill structure backwater effects;

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 the phasing is independent of the length of river being tackled. However, the amount of material that may need to be stockpiled for later use may differ between reaches;  the phasing of installation does not appear to conflict significantly with the MCA scoring, as there is a tendency for higher scoring measures to be installed earlier. This difference will have little practical impact providing there is no long-term delay between installations; and  the MCA analysis shows that the selection of the improvement measures gives the best solution for delivering the RWRS. However, the analysis has shown that something else needs to be addressed. When looking at the other options, G3 ‘Targeted maintenance’ is the best alternative option compared to all others, including 'Continue as present' and ‘Do nothing’. The profound difference between these options is that 'Targeted maintenance' scores positively, and therefore, contributes towards the RWRS delivery; whereas 'Continue as present' and ‘Do nothing’ have the lowest scores (all negative except for ‘Do minimum’ in Reach 28 and Reach 31) and so are making RWRS delivery more difficult. This is also true when compared to the 'Do nothing' scenario which has a smaller negative score. This need for change is further reinforced by the consultation process where significant numbers of stakeholders expressed their desire to see a change in the current management of the river, and also broadly supported the RWRS objectives. Therefore, to provide early benefit for both river and stakeholders, the existing management regime should be changed to 'Targeted maintenance' until improvement measures can be implemented to replace it, whether at section, reach, unit, or river level. The initial cost estimate by Atkins for the recommended restoration design of Unit 47 is £403,000 (to the nearest thousand). This estimate has been revised after further consideration of alternative materials and techniques and the phasing of the works. The revised cost estimate for Unit 47 is £338,000 (to the nearest thousand) a potential saving of 16%. However, although a cost saving may be achievable, this will be very much dependent on the findings at the detailed design stage once a review of additional site specific survey information ( bathymetric and topographic) is carried out. This revised estimate is less than previous cost estimates (JBA, 2007; Halcrow, 2008a) although it is difficult to compare the three estimates due to the assemblage of different components. There also needs to be allowance made for different dates of each estimate. Table 7.11 summarises the differences between the three different cost estimates.

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Table 7.11 - Comparison of costs between 2007 and 2010 studies Halcrow (2008a) JBA (2007) Atkins (Sept 2011) Length Cost Length Cost Length Cost (km) (£) (km) (£) (km) (£) Fencing* 0 0 4.8 £31,734 7.2 £28,840 Large woody debris 0.36 £ 7,000 0.13 £5,720 In-stream structures 0.36 £29,000 0.04 £49,777 Cross section modifications 2.16 £129,000 4.8 £1,055,600 1.6 £83,906 Bed raising 2.16 £332,000 6.1 £1,090,620 0.5 £189,231 Landscape** - 4.8 £5,289 2.3 £17,820 Reconnections - 0.5 £27,868 Restoration 0.5 - Structure modification £704,000 £500,000 Totals: 5.04 £1,201,000 16.19 £2,758,243 5.07 £403,162 Overall Unit rate: £/km £166,829 £383,143 £55,995 Density of features 0.70 2.25 0.70 Density adjusted rate £/km £116,780 £861,499 £39,196

Notes: *Fencing length excluded from the calculation of the total length of restoration features. **Includes tree felling and tree planting.

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8. Scoping 8.1 Introduction

8.1.1 The need for Environmental Impact Assessment The types of river restoration measures identified by this feasibility study are likely to fall within the Environment Agency’s permitted development rights under Schedule 2, Part 15(b), of the Town and Country Planning (General Permitted Development) Order 1995 SI 95/418 (referred to as the GPDO) and it is anticipated that planning permission will not be required. As the details of any future schemes are developed, consultation with the relevant local planning authorities regarding the proposals will be required to confirm this view. Any works that are undertaken under Schedule 2, Part 15(b) of the GPDO fall within the remit of the Environmental Impact Assessment (Land Drainage Improvement Works) Regulations Statutory Instrument (SI) 99/1783 (as amended by SI 2005/1399 and SI 2006/618). SI99/1783 (as amended) requires that the potential for the works to give rise to significant environmental effects is considered. Where significant environmental effects are likely to occur there will be a need to undertake an EIA (Environmental Impact Assessment) of the scheme. In cases where there are no significant environmental effects the intention not to produce an Environmental Statement will need to be advertised. The advertising process will be undertaken once the details of any schemes have been developed, and the relevant local planning authorities have been consulted regarding the proposals. Although a statutory EIA (with the production of an Environmental Statement) is unlikely to be required, it is Environment Agency policy to undertake EIA for its own works. Therefore, a risk- based non-statutory environmental assessment for any subsequent restoration schemes will be undertaken, and this will be documented by an Environmental Report. 8.1.2 Environmental scoping exercise As part of this feasibility report, an environmental scoping exercise on the preferred restoration option for each reach was undertaken. The purpose of this exercise was to determine what issues will need to be considered during the Environment Agency’s non-statutory EIA for any forthcoming restoration scheme. The scoping exercise will also form part of the required documentation to gain internal approval for the scheme. The purpose of the environmental scoping exercise is to:  Provide a record of the scoping process.  Identify the methodology for undertaking and evaluating the EIA.  Identify what environmental issues will be scoped into the EIA.  Identify what environmental issues will be scoped out of the EIA.  Identify environmental constraints and opportunities that will need to be addressed at the detailed design stage.  Consult with statutory bodies and interested parties on the proposed scope. Whilst there is no formal requirement for scoping to be undertaken in the (IEMA, 2004), environmental scoping is a fundamental component of the EIA process because it identifies the key environmental issues and avoids progressing issues that are considered to be less important through to the next stage of EIA (IEMA, 2004). Figure 8.1 illustrates where environmental scoping occurs within the EIA process, and how this has been applied to Unit 47.

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Environmental Scoping: Unit 47: Tatterford Common to Fakenham Mill

SCHEME CONCEPT Understand and establish key project drivers and objectives of the Feasibility Assessment.

SCREENING Define the environmental baseline features of each reach in Unit 47. Considers a number of ‘River restoration’ and ‘Targeted maintenance’ options and measures that could be applied and implemented individually or in combination to restore Unit 47 to ‘unfavourable recovering’ or ‘favourable’ ecological condition.

CONSULTATION & RESULTS & ANALYSIS

Communicate with key statutory stakeholders and the local community to capture the ‘big’ issues, and identify the constraints and opportunities of the proposed restoration measures.

Analysing the feedback obtained from the consultation process

MULTI CRITERIA ANALYSIS (MCA) WORKSHOP Apply the MCA tool against ecology, project delivery and technical aspects that help inform the selection of appropriate measures for Unit 47.

Use results of MCA and professional judgement to select recommended option(s).

SCOPING OF THE PREFERRED OPTIONS FOR UNIT 47 Focusing on the significant environmental issues associated with the proposed restoration measures.

SCOPED IN SCOPED OUT

Request a formal scoping opinion to the planning authority to inform the project team the level of EIA required.

Undertake either a full Environmental Impact Assessment or Environmental Report for each unit

Figure 8.1 - Environmental Scoping within the EIA process

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8.2 Method of assessment The project is still at a strategic level so detailed monitoring of baseline environmental conditions has not been carried out. This means that professional judgement, in combination with the methodology explained below, was used to determine what environmental issues will be assessed in more detail at the next stage of the EIA process. The options and measures that have been detailed in Table 8.2 require scoping for potential constraints and opportunities. To carry out this level of assessment, the European Commission guidance on Screening and Scoping (2001) has been adapted to determine what type of constraints and opportunities are likely to give rise to significant effects. Table 8.1 presents the framework for classifying and evaluating the significance of potential environmental effects of the preferred river restoration option. Table 8.1 - Classifying and evaluating the significance of potential environmental effects in the scoping process (adopted from European Commission, 2001)

Key Questions Used In Environmental Scoping Measure Are the final proposed works out-of-character with the local Yes / No environment? What is the scale of the effect? Limited / Widespread Is there potential for effects on the environment outside of study Yes / No area? Are there many people affected? Yes / No

Are there protected, rare or endangered features affected? Yes / No

Is there a risk of breaching industry standards? Yes / No

Probability of occurrence Yes / No

What is the length of the effect? Short / Medium / Long

Is the effect reversible? Yes / No Major / Moderate / Significant effect (without mitigation) Minor

8.2.1 Restoration Options and Measures Restoration options and measures outlined in Table 8.2 have been grouped to simplify the scoping process and to avoid repetition in assessing effects. The groups are:  In-channel works; berm creation; gravel glides; channel re-sectioning; deflectors; channel realignment and lowering mill sill levels.  Floodplain works; lowering spoil embankments; re-connecting to existing floodplain surface water drainage; new backwaters and tree thinning.  Other works: ‘Targeted maintenance’, tree planting and fencing. Using the information within Table 8.1 and professional judgement, the recommended restoration options and measures are assessed in terms of their significance of effect. This report has adopted the following categories to determine significance of effect:  Potential adverse effect  Neutral effect (or one that could be designed out)  Potential positive effect.

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Section 8.3 presents the results of the scoping assessment. 8.3 Results of scoping The scoping assessment was undertaken by using professional judgement and best practice literature (IEMA, 2004; and European Commission, 2001). It is considered to be in accordance with the legislation, procedure and guidance in force and with reference to international standards of EIA best practice. This section summarises the results of the scoping assessment. The scoping assessment included the opinions of public and private stakeholders captured during the initial public ‘drop-in days’ and various consultations with statutory stakeholders (refer to Chapter 4 for more information). The early consultation within the EIA process provided timely and appropriate opportunities for public and stakeholder involvement. One of the key outcomes of early engagement has been the identification for the need to implement targeted maintenance ahead of main river restoration works. The environmental scoping assessment has identified issues to be scoped in and out of the EIA process. Those issues scoped in to the assessment will require further assessment for their potential adverse or beneficial cumulative effect at the next stage of the EIA (detailed design). Table 8.2 summarises the potentially key adverse and beneficial impacts associated with the preferred restoration options for Unit 47. It provides more accurate information on exactly what data and actions are required for the next stage of the EIA assessment (e.g. Environmental Report or Statement). Table 8.3 lists those environmental issues that were scoped into the next stage of the EIA, and Table 8.4 lists those issues that were scoped out. Information contained within Tables 8.2 to 8.4 ensures that the scope of the EIA will be focused only on key issues.

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Table 8.2- Environmental scoping assessment for recommended restoration options

In-channel works Floodplain works Other works Scoping Assessment Aspect of Proposed Works Giving Rise to Potential Impact Scoped Scoped In Out Individual Environmental Environmental Group Features Operational Phase Construction Phase Phase Construction Berm Gravel Glide Channel Re- sectioning Deflectors to Connect Channels Channel Realignment Sill Lower Mill Levels Lower Spoil Embankments Re-connect to Floodplain Drains New Backwaters / Tree Felling Thinning Targeted Maintenance Fencing Planting Tree

Construction activities include additional vehicle movements. The number of Heavy Goods Vehicles (HGVs) needed to transport the required gravel is low Air quality  x x  and transport will be undertaken over a short-period of time. Therefore, adverse impacts to local ambient air quality are unlikely to be significant.

Air and Climate The restoration measures proposed are varied and designed to adapt to future uncertainty. Tree planting has the potential to become a natural carbon sink, Climate change therefore offsetting the impacts of tree felling. However, the restoration is x  x  unlikely to have a significant impact on climate change and is therefore scoped out.

Restoration of the river through introducing greater sinuosity or improvements to the riparian habitats should return the target reaches to a more natural state. Once established, these works would be expected to improve the visual x  amenity value of the reaches through softening the “man-made” feel of certain Landscape Landscape and sections of the river, especially those where the channel has been canalised character &  x visual amenity and all sinuosity has been lost. visual amenity Tree felling and pollarding to improve river biodiversity and to provide woody debris for in-channel works are likely to impact locally on landscape and visual  x amenity. However, the magnitude of these works is low, and tree planting within the floodplain will offset tree removal.

Physical works to the banks ( e.g. re-profiling, construction of berms, reduction in spoil banks to source gravels and reconnect to floodplain) as well as tree Protected management and access and plant movements, have the potential to result in  x  x species disturbance and/or damage to protected species and their habitats, such as water voles, otters, bats and badgers.

Ecological improvement of the river is the key objective of the project. The works are likely to result in long term improved habitat for key aquatic fauna. This may include Desmoulin’s whorl-snail (Vertigo moulinsiana), bullhead x  (Cottus gobio), white-clawed crayfish (Austropotamobius pallipes) and brook lamprey (Lampetra planeri). Flora & Fauna

Increasing the number and range of riffles, runs, pools and flow types will have Fisheries, adverse impacts on fish and aquatic populations during construction but will   invertebrates provide significant long term improvements to the habitats available for a wide  x and flora range of macro-invertebrates.

One of the key PSA targets is the improvement of the Ranunculion fluitantis and Callitricho-Batrachion vegetation community which is characteristic of the x  river type.

Works including bank re-profiling and bed-level raising have the potential to  x disturb in-situ sensitive aquatic species.

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In-channel works Floodplain works Other works Scoping Assessment Aspect of Proposed Works Giving Rise to Potential Impact Scoped Scoped In Out Individual Environmental Environmental Group Features Operational Phase Construction Phase Phase Construction Berm Gravel Glide Channel Re- sectioning Deflectors to Connect Channels Channel Realignment Sill Mill Lower Levels Spoil Lower Embankments Re-connect to Floodplain Drains New Backwaters / Tree Felling Thinning Targeted Maintenance Fencing Tree Planting Construction of some restoration options may leave open areas of bare ground which may give rise to opportunistic invasive plants. Reconnection to floodplain features (e.g. gravel pits, existing field drains and wetland pools) has Invasive and the potential to spread invasive species such as Crassula and Azolla. Any non-native    x reconnections considered as part of the restoration will require a site specific species assessment of existing constraints and control options. Good construction and site management, including plant maintenance (e.g. vehicle cleaning and disinfection) will be necessary to prevent the spread of such invasive species. Additional trees will, in time, provide submerged roots for colonisation by numerous macro-invertebrate species, from caddis flies to crayfish. x 

The surrounding landscape will also benefit from additional tree planting.  x Trees However, there may be tree thinning and felling in certain locations to improve habitat diversity.  

Physical changes through excavations, bank re-profiling, bed-raising and x  infilling works to improve sinuosity and channel narrowing.  x Geomorphology Re-connecting field drains to the main river may improve surface water drainage x 

River restoration measures such as lowering mill sill levels, lowering spoil x  embankments, channel re-sectioning and installing gravel glides all have the

potential to change flood risk, both locally and further afield. This will need  x Drainage and assessment at the detailed design stage. flood risk  x

Water Bed raising with gravels and the creation of new pool, riffle and glide sequences all have the potential to improve existing water quality within the x  Water quality unit. This requires further investigation at the next stage of the EIA.  x In-channel construction will disturb bank and bed sediments and result in the release of sediment to the river and temporarily reduce water quality.  x

Angling: The rehabilitation works would provide significant opportunities to improve river angling. Canoeing: Whilst there are no statutory navigation Humans rights on the River Wensum, where there is agreed access for canoeists,    x impacts and opportunities will be assessed. Where there is no agreed access for canoeists, this will be treated like a normal constraint.

Rehabilitation works may involve minor realignments of the river channel which may result in the permanent loss of a small amount of grazing or arable land x  immediately adjacent to the river. The lowering of river banks and / or reconnection of the river to adjacent field drains may result in more frequent small scale flooding of the functional Land use floodplain. However, the floodplain of the River Wensum is within the Broads  x Human ESA scheme so as to support extensive and traditional management regimes. Environment Although the ESA scheme is closed to further entrants, the River Wensum is a x  target area with regard to Higher Level Stewardship. If changes in hydrological regime were to impact the feasibility of management prescriptions under existing schemes, then schemes would need to be modified.

Historic Earthworks and construction may give rise to adverse effects on the historic  x  x environment environment. Excavation of banks for channel realignment and the lowering of raised spoil embankments may have adverse effects on unknown items of Unit 47 Tatterford Common to Fakenham Mill_Final.docx 134

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In-channel works Floodplain works Other works Scoping Assessment Aspect of Proposed Works Giving Rise to Potential Impact Scoped Scoped In Out Individual Environmental Environmental Group Features Operational Phase Construction Phase Phase Construction Berm Gravel Glide Channel Re- sectioning Deflectors to Connect Channels Channel Realignment Sill Mill Lower Levels Spoil Lower Embankments Re-connect to Floodplain Drains New Backwaters / Tree Felling Thinning Targeted Maintenance Fencing Tree Planting historic significance. Engineering works may have long-term adverse effects on mill buildings which   are of historical and cultural importance.

Noise is expected to be created by construction works but this will be Noise & minimised through mitigation and best practice construction techniques. There  x x  vibration will be no operational noise associated with the development.

Construction: It is expected there will be a short term increase in traffic Traffic & through local villages during construction as a result of importing materials to  x  x transport site.

The recommended restoration works are not likely to give rise to either adverse or positive effects on existing soils. An attempt will be made to balance cut and fill wherever possible to reduce soil demand and wastage. Soils Demand for soil will be met by using local sources where practicable. Surplus  x  x soil (e.g. through the creation of berms and channel re-sectioning) will be disposed of on the landholding where practicable and if not, off-site as a form of waste.

The recommended restoration works are not likely to give rise to either Geology x x x  adverse or positive effects on existing drift geology or deep geology.

Historical contamination: Desktop investigations have not revealed any significant historical industrial land use along the river margins other than that Soils & Geology associated with mills.

However, various samples taken at mills along the Wensum have failed to Ground meet the waste acceptance criteria required for landfill as well as standards for    x contamination hazardous, non-hazardous and inert waste for landfill due to contaminants that are not covered by the Soil Guidance Values. Further checks prior to construction would need to be made on the contaminants not covered by the Soil Guidance Values.

It is unlikely that the proposed works will generate excess waste that will have to be managed through a waste exemption licence or be taken off-site. A Site Waste Waste Waste Management Plan will be implemented as part of the Environment  x x  Agency’s best practice approach to waste management.

Legend Potential adverse effect Neutral effect Potential positive effect

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Table 8.3 - Issues scoped into the EIA process

Environmental Individual Justification Group Environmental Features Construction work has the potential to adversely affect Protected species protected species such as water vole otter, bats and badger. Fisheries, The key impacts of restoration works on these species invertebrates and during construction and operation will need to be flora identified and assessed. Invasive species represent a threat to the structural Flora and fauna integrity of works, a risk to human health for both construction workers and the wider public, and also to Invasive and non- the natural environment by taking over habitats to the native species detriment of native plant and animal species. It can be very expensive to remove invasive species through removal and disposal of surrounding soil. Damage to trees may be caused by direct removal or Trees by changes in the soil character upon spoil removal or deposition. The key construction and operational effects on cultural Historic heritage and archaeology need to be identified. There are concerns expressed over long-term land use Land use issues, and how the works could impact ESA agreements and other agri-environment schemes. It is expected there will be a short-term increase in Human Traffic & transport traffic on the local road network during construction as environment a result of importing materials to site. The rehabilitation works would provide opportunities to improve river angling. Whilst there are no known Recreation statutory navigation rights on the fluvial River Wensum, where there is agreed access for canoeists, impacts and opportunities will be assessed. There are likely to be short-term localised impacts on land use through construction disturbance. Landscape Land use The key construction and operational effects of the character and restoration works on the landscape character and visual amenity visual amenity of the Wensum valley need to be identified. Physical changes from excavations on geomorphology Geomorphology need to be investigated in more detail at the next stage of the EIA. Water Drainage and flood The impacts of local restoration schemes on flood risk environment risk will need to be assessed. Water quality could be impacted / contaminated during Water quality construction. The recommended restoration works are not likely to give rise to either adverse or positive effects on existing Soils & geology Soils soils. However, there may be issues relating to balancing quantities of supply (cut) and demand (fill) which have environmental implications.

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Table 8.4 - Issues scoped out of the EIA process

Environmental Individual Justification Group Environmental Features There will be short-term, localised impacts on air quality during construction. These impacts are considered to be temporary and not significant enough to warrant further Air and climate Air quality investigation. Standard best practice in construction should be adequate to manage these impacts and therefore air quality will not be considered further in the EIA. Noise is expected to be created by construction works, Human but this will be minimised through mitigation and best Noise & vibration environment practice construction techniques. There will be no operational noise associated with the completed works. The restoration works are not likely to give rise to either Soils & geology Geology adverse or positive effects on existing drift geology or deep geology. It is unlikely that the proposed works will generate waste Waste N/A that will have to be managed through a waste exemption licence or be taken off-site.

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9. Consents

A number of consents and permissions are likely to be required in order to implement the recommended river restoration options and measures for Unit 47. These are listed in Table 9.1, together with the organisations that are responsible for granting them and a summary of the action needed as the EIA progresses. Table 9.1 - Likely planning consents and permissions

Likely Organisation Comment Consent

The Environment Agency has permitted development rights under the Land Drainage Act 1991 and Water Resources Act 1991 to carry out necessary restoration works within main rivers. The River Wensum is a main river so works within the channel Environment Agency do not require planning consent. The permissive rights extend to 9m either side of the main channel. Planning Local planning authorities will be consulted to permission determine if any aspects of proposed river restoration schemes require planning permission.

Planning permission will be obtained from the local authority if any works are not covered as ‘Permitted Local Planning Authority Development’ under Part 14, Schedule 2 of the Town & Country Planning (General Permitted Development) Order 1995.

The Environment Agency will screen individual Environmental restoration projects for their environmental risk. Impact In accordance with Works are not likely to require a full EIA Assessment Environment Agency EIA (Environmental Statement) but as best practice the (statutory / non policy. Environment Agency will carry out an appropriate statutory) level of environmental assessment.

If any of the works (particularly the mill works) involve alterations to listed buildings or structures, consultation with the relevant Conservation Officers Listed building from the local authorities will be required. A separate Local planning authority consent Listed Building Consent may be required from the local authority for works affecting listed buildings or structures. This should not affect permitted development rights.

Development and Flood Risk Team has been consulted and a Flood Defence Consent will be Flood Defence Environment Agency required. This may include the need for a formal Consent Flood Risk Assessment if planning permission is required.

Consent will be required from the Internal Drainage Norfolk Rivers Internal IDB Consent Board for any works to watercourses for which they Drainage Board have responsibility as the drainage authority.

Natural England will need to give their written assent Assent under for any works to be carried out within or affecting the Section 28 of River Wensum Site of Special Scientific Interest. The the Countryside Natural England proposals will be developed in partnership with and Rights of Natural England, and assent will be obtained prior to Way Act any works starting on the SSSI.

Consideration of Consideration under Regulation 61 will be required need for Natural England due to the designation of the River Wensum as a Conservation of Special Area of Conservation (SAC). It is anticipated

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Likely Organisation Comment Consent Habitats and at this stage that the works will be “directly connected Species with or necessary to the management of the site” and Regulations therefore an appropriate assessment will not be Assessment required. This will be confirmed in writing with Natural England.

Natural England is actively working with the project team to assent the proposed works and ensure that the mitigation measures outlined below will not adversely affect protected species or their habitats. A consent letter from Natural England is needed before Protected any works can begin. species and Natural England Otters, water voles, bats and badgers are known to associated be present along the River Wensum. Since these are licences protected species, there will be a requirement to implement some mitigation measures as part of the proposed river restoration scheme. Consent from Natural England will be required to carry out mitigation activities if these require trapping or destructive search for water voles, for example.

Waste The requirement for a Waste Management Licence Management Environment Agency will be reviewed once detailed designs are available. Licence

Landowner Various landowners We need to continue liaison with key landowners. consents

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10. Project Risks

A number of key project risks may delay the delivery of the recommended option for Unit 47 and these include: 1. Uncertainty of availability of funding to implement recommended option.

2. Protected species survey and mitigation.

3. Inappropriate maintenance both prior to and post restoration.

4. Obtaining landowner consents to undertake enhancement works on private land, as well as

other permissions and consents (e.g. Flood Defence Consent).

5. Cost associated with the implementation of detailed designs.

6. Changes in UK or European environmental legislation.

7. Extreme weather conditions and / or flooding.

To manage these risks it is recommended that there is ongoing communication with key stakeholders including landowners, local planning authorities, NCC, internal Environment Agency functions, the Norfolk Rivers IDB, Natural England and the local communities within Unit 47 (Table 10.1).

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Table 10.1 – Key project risks that may delay the delivery of the recommended options for Unit 47 Risk Proposed Mitigation Level of risk Ongoing and open discussion with landowners and High other stakeholders to inform them of the potential for Landowners not giving ecological improvements through enhancement permission for works. Listen to landowners concerns and work enhancement works collaboratively to identify alternative methods or materials for proposed works. Availability of funding for Raise profile of project nationally and seek early High scheme identification of external sources of funds. Measures to prevent adverse impacts will be Medium The need to mitigate and undertaken in accordance with the Environmental plan around protected Good Practice Site Guide (Environment Agency, species 2005) and Planning Policy Statement 23. Work collaboratively with the Environment Agency Medium Inappropriate maintenance Operations Delivery Team and the IDB to identify and prior to and post restoration agree an appropriate maintenance protocol within the context of the Targeted Maintenance option. The cost of each restoration option will vary according Low to technical constraints such as access and scale of Uncertainty regarding costs project. Cost will need to be revised during the detailed design stage. Lack of forward momentum Low Ongoing consultations and discussions with the local to keep the scheme residents and key stakeholders. Provide regular progressing to achieve updates in the form of a newsletter. benefits in the river Change in UK or European Keep abreast of proposed changes in legislation so Low environmental legislation any changes in detailed design can be informed at an (e.g. fisheries legislation) early stage. Monitor weather conditions and ensure new and part Low Extreme weather conditions built features are secured at the end of each working and / or flooding day to prevent them being damaged by extreme weather or flood events.

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11. Conclusions and Recommendations 11.1 Conclusions This report identifies river restoration options and measures that could be implemented to restore Unit 47 (Tatterford Common to Fakenham Mill) of the River Wensum Site of Special Scientific Interest (SSSI) to ‘unfavourable recovering’ or ‘favourable’ ecological condition. Options have been identified that will deliver physical modifications to improve the ecological condition of the River Wensum. If river alterations are not delivered there remains a risk that the Government Public Service Agreement (PSA) target for SSSI condition will not be met and the river will not be returned to ‘unfavourable recovering’ or ‘favourable’ ecological condition. Consideration has been given to terrestrial SSSI units on the functional floodplain where there is the prospect of improving any hydrological linkage with the river. Multi-Criteria Analysis A MCA was applied across a range of potential restoration options. This allowed options to be assessed individually and against each other in terms of technical, economic and environmental constraints or opportunities. The MCA is a powerful tool for appraising all options and associated measures in a consistent, replicable and transparent way. It can be used to identify those options that will move the SSSI unit towards ‘unfavourable recovering’ or ‘favourable’ ecological condition and those that do not. It also provides an indication of the relative importance of the options and their measures in achieving ‘unfavourable recovering’ or ‘favourable’ ecological condition for a particular reach. How those options and measures are applied to a reach is a case of professional judgement. The results of the MCA show that the recommended option for Unit 47 is a combination of major and minor in-channel restoration measures combined with changing the operational procedure around existing mill infrastructure. Costs The estimated cost of the recommended options for the unit is £375,000 (to the nearest thousand) reduced to £332,000 when cost saving are applied which is less than previous estimates. This is partly a reflection of the restoration design philosophy used which is to provide features that the river cannot restore itself (i.e. back channels, bed raising, gravel glides) and to provide features that will ‘kick start’ a wider recovery process (i.e. deflectors, berms in key locations, channel re- sectioning). It is also a reflection of a detailed cost estimate exercise based on a more in-depth understanding of the restoration requirements for this unit. Environmental issues This feasibility report has also provided baseline data for a range of environmental criteria. This, and the information contained within Chapters 4 to 8, has allowed environmental issues to be scoped in or out of the EIA that will be required to accompany the detailed design of restoration schemes. Consultation To date, consultation with key statutory and non-statutory stakeholders indicates strong in- principle support for restoration to Unit 47.

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11.2 Recommendations To keep up the momentum for this project, the following recommendations are made: 1. To improve the likelihood of delivery of restoration schemes it is important that the project team continues to consult on a regular basis with key stakeholders, including, but not limited to:  Landowners  Anglers  District and County Council planning authorities to determine the level of EIA required and any supporting planning consents  Internal Environment Agency functions  Natural England  Norfolk Rivers Internal Drainage Board. 2. ‘Targeted maintenance’ should be implemented as soon as possible to demonstrate a commitment to continued management of the river where this can be justified. This will also drive further action to implement the remaining recommended restoration options.

The environmental issues that have been scoped into the next stage of EIA should be considered as part of a best practice Environmental Report.

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12. References

1. @One Alliance (2007) River Wensum Aquatic Macrophyte Survey: AMP4 Water Resources Environment Programme: Habitats Directive Review of Consents. 2. Atkins (2010) River Wensum Restoration Strategy, Mill Operating Protocol. Draft Report. 3. Centre for Aquatic Plant Management (CAPM) (2002) Macrophyte Survey on the River Wensum. 4. Econ (1999) River rehabilitation feasibility study of the River Wensum (Norfolk)-Phase 2. Report to Eastern Area, Anglian Region, Environment Agency, Norwich, UK, 153pp. Perrow, M.R. & Newson, M.D. 5. English Nature (1993) Notification of SSSI Status: River Wensum, Norfolk. 6. Entec (2010) Habitats Directive Review of Consents - Stage 4 Options Appraisal: River Wensum SAC. Report for the Environment Agency. 7. Environment Agency (1995) River Corridor Survey of the River Wensum (Anglian Region, Eastern Area). 8. Environment Agency (1999) River Wensum Water Level Management Plan. Environment Agency (Anglian Region, Eastern Area). 9. Environment Agency Web-based Flood Mapping: http://maps.environment- agency.gov.uk/wiyby/wiybyController?x=531500.0&y=181500.0&topic=floodmap&ep=map&scale =3&location=,%20City%20of%20London&lang=_e&layerGroups=default&textonly=off 10. Environment Agency / Natural England (2004) The state of England’s chalk rivers: Summary report by the UK Biodiversity Action Plan Steering Group for Chalk River. [Online: http://www.freshwaterlife.org/servlet/BinaryDownloaderServlet?filename=1152695564918_chalk_ riv_summary_834762_1_.pdf. Accessed November 2009. 11. Environment Agency (2004) Crayfish Distribution in the River Wensum – Results & Observations from the 2003 Ecological Appraisal Fisheries Sampling Programme. EA, Anglian Region, Eastern Area. 12. Environment Agency (2007) The River Wensum Water Level Management Plan. Report produced by Entec UK Ltd. 13. Environment Agency (2009a) Position statement on hydropower. [Online: http://www.environment- agency.gov.uk/static/documents/Research/Hydropower_position_statement_FINAL_English.pdf. Accessed August 2009]. 14. Environment Agency (2009b) Good practice guidelines annex to the Environment Agency hydropower handbook: The environmental assessment of proposed low-head hydro power developments. [Online: http://www.environment- agency.gov.uk/static/documents/Business/Low_Head_Hydropower_August_2009.pdf. Accessed August 2009]. 15. Environment Agency (2009c) Water Resources GIS. October 2009 version. 16. Environment Agency (2010). What’s in your backyard. [Online: http://www.environment- agency.gov.uk/homeandleisure/37811.aspx. Accessed August 2010]. 17. European Commission (2001) Guidance on EIA Scoping. Environmental Resources Management. 18. Gillian, S; Boyd, K; Hoistma, T and Kauffman, M (2005) Challenges in developing and implementing ecological standards for geomorphic river restoration projects: a practitioner’s response to Palmer et al. Journal of Applied Ecology. 19. Halcrow (2008a) Estimating costs of delivering the river restoration element of the SSSI PSA target. Final report prepared for the Environment Agency. 20. Halcrow (2008b) Fakenham Flood Risk Assessment. Phase 1 Ecological Survey. January 2008 21. Heritage Gateway Website: http://www.heritagegateway.org.uk/gateway/advanced_search.aspx. 22. IEMA (2004) Guidelines for Environmental Impact Assessment. Unit 47 Tatterford Common to Fakenham Mill_Final.docx 145

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23. Jackson M.J. & Howlett D.J. (2000) A Survey of the Terrestrial and Amphibious Molluscs of the Upper Wensum Valley. October/November 1999. 24. JBA Consulting (November 2007) River Wensum Restoration Strategy, Supporting Technical Report for Natural England. 25. JNCC (2002) Standard Data Form DoE SPA, SCI and SAC: River Wensum. Version 2.1, Natura 2000 Data Form. 26. Mant, J. & Fellick, A. (2007) The River Wensum, Norfolk: An assessment of the current approaches to river restoration along the River Wensum and their potential to support habitat requirements. A report to Natural England (prepared by the River Restoration Centre, Bedfordshire). 27. Multi-Agency Geographic Information for the Countryside (MAGIC) Website address: http://www.magic.gov.uk/. 28. National Biodiversity Network Gateway Website: http://www.nbn.org.uk/ 29. Natural England (2007) Conservation Objectives and definitions of favourable condition for designated features of interest: River Wensum SSSI. Consultation Draft, Norfolk and Suffolk Team. 30. Natural England (2010) SSSI Condition Assessment – River Wensum SSSI [Online: http://www.sssi.naturalengland.org.uk/Special/sssi/reportAction.cfm?report=sdrt13&category=S&r eference=1006328 Accessed September 2010). 31. Norfolk Rivers Internal Drainage Board (2007) Standard Maintenance Operations for rivers. 32. North Norfolk District Council (2009) Landscape Character Assessment: Draft Supplementary Planning Document. [Online: http://www.northnorfolk.org/ldf/documents/Draft_Landscape_Character_Assessment_- _Consultation_Document_(WEB).pdf. Accessed September 2010]. 33. RCC (2007) The Wensum Norfolk, An assessment of the current approaches to river restoration along the River Wensum and their potential to support chalkstream habitat requirements. The River Restoration Centre (RRC), Final report to Natural England. 34. Sear, D.A., Newson, M., Old, J & Hill, C. (2006) Geomorphological Appraisal of the River Wensum Special Area of Conservation. English Nature Research Reports, No 685, by GeoData, University of Southampton. 35. Stansfield, J., Adams, C., Whiting, C., Markwell, H. & Brown, R. (2001) River Wensum Invertebrate survey and ecological assessment 2001. Environment Agency, Fisheries, Recreation & Biodiversity: Ecological Appraisal Team, Ipswich. 36. Wensum Valley Project (1994) Wensum Valley Strategy, Norfolk. Produced by the Joint Advisory Panel of the Wensum Valley Project.

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Appendices

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Appendix A - Multi-Criteria Analysis technical note

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A.1 MCA Criteria & Options/Measures Feedback from the MCA workshop with the Environment Agency and Natural England confirms the need for greater clarification of the MCA process and in particular how the criteria and options/measures are defined. This technical note is to address those queries. Within the criteria definitions, explanation is given of the 5 point scoring to which the weightings are applied. Typical scoring considerations for each criterion have been given to provide greater consistency of scoring. A.1.1 Criteria and criteria group definitions The criteria are divided into 3 major groups:  Ecology  Project Delivery  Technical. The ecology is the main driver for the project and so has to have the highest weighting, which is 1. The project objectives do not stand alone. Not only does the project have to succeed, but it must also be seen and felt to succeed. Therefore the aspirations of the stakeholders in the project also have to be recognized. This is nearly as important so the weighting for this is 0.9. To make a difference to the ecology the RWRS has to be implemented. An assessment of the choices implementation generates needs to be made. We have called this group technical criteria. There has to be a consideration of the practical delivery of the project in the real world as it is generally true that technical complexity generates cost, and impacts on quality and time. The weighting needs to be reasonably high, but not as high as the previous items, so 0.8 is used. Each of the three criteria groups is made up of a number of related criteria, which in turn have relative importance and hence need different weightings. These are explained by group. A.1.2 Ecology The primary objective of the project is to improve the ecology of the River Wensum. This falls into two parts: legally protected ecology and the rest. So, as a crude split the ecology needs to be divided into at least 2 sub groups. However, the legal protection is variable and progressive, with some species and habitats afforded greater protection than others. To demonstrate compliance with the law the criteria analysis needs to reflect the progressive nature of the legal protection. We have therefore divided the legally protected ecology into 3 sections to reflect the levels of importance:  International: SAC  National: SSSI  Regional: BAP. To this we add the non-protected ecology. This has to be included so as to satisfy the Environment Agency’s broader legal duty to consider and further conservation. This gives a fourth sub-group as follows:  Local: Contribution to overall ecology. In terms of RWRS these 4 items are not equal. The definitions and weightings are explored below.

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A.1.3 Compliance with National Designation: SSSI The primary driver for the RWRS is the Defra PSA target based on SSSI condition (95% of SSSIs by area to be in favourable or unfavourable recovering condition by December 2010). The SSSI covers the following: Table A.1 - SSSI designation targets

Statutory / Non Statutory Conservation Targets Drivers SSSI designation  Flow: Flow regime should be characteristic of the river. Levels of abstraction should not exceed the generic thresholds laid down for moderately sensitive SSSI rivers by national guidance.  Water quality: Biological GQA Class B; Chemical GQA Class B; No unnaturally high loads of suspended solids.  Phosphate: An annual average phosphate concentration of 0.05mg/l from the upstream limits of the SSSI to the confluence of the River Wensum with the White Water (the tributary that drains from East ), and 0.1mg/l from that confluence to the downstream limit of the SSSI.  Siltation: No excessive siltation. Channels should contain characteristic levels of fine sediment for the river type.  Channel form: should be generally characteristic of river type, with predominantly unmodified planform and profile. Bank and riparian zone vegetation structure should be near-natural.

So from a project perspective the national protection has to have the highest weighting. Thus, it is allocated the highest weighting which is 1. With regard to scoring the following applies (Table A.2): Table A.2 - SSSI scoring

Compliance with National Designation: SSSI Score Description Typical Effect +2 High relevance Direct immediate improvement in designated item. +1 Low relevance Moving towards favourable condition. 0 Neutral No change. -1 Low Detriment Moving away from favourable condition. -2 High Detriment Permanent adverse changes.

A.1.4 Compliance with International Designation (SAC): The SAC covers the following:

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Table A.3 – SAC designation targets (Natural England, 2007)

Statutory / Non Statutory Conservation Targets Drivers SAC Designation The conservation objectives for the European interest features on the SSSI are:

to maintain*, in favourable condition, the:

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

to maintain*, in favourable condition, the habitats for the population of:

 Bullhead (Cottus gobio)  Brook lamprey (Lampetra planeri)  White-clawed crayfish (Austropotamobius pallipes)  Desmoulin’s whorl snail (Vertigo moulinsiana)

*maintenance implies restoration, if the feature is not in favourable condition.

PDFs of English Nature publications on the ecology and monitoring of the five European features can be downloaded from the publications catalogue on the Natural England website (www.naturalengland.org.uk).

The international protection must also rank highly, but from a project perspective, not as highly as the national importance; a weighting of 0.8 was used. With regard to scoring, Table A.4 outlines how SAC targets have been scored. Table A.4 –SAC scoring

Compliance with International Designation (SAC) Score Description Typical Effect +2 High relevance Direct immediate improvement in designated item. +1 Low relevance Moving towards favourable condition. 0 Neutral No change. -1 Low Detriment Moving away from favourable condition. -2 High Detriment Permanent adverse changes.

A.1.5 Compliance with Regional Designation (BAP): The biodiversity action plan most relevant to the River Wensum is the chalk rivers action plan. There are a number of additional species and habitat action plans that may be affected by river restoration on the Wensum. These are summarised in Table A.5. This criterion is also intended to cover protected species issues (e.g. those covered by the Wildlife and Countryside Act).

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Table A.5 – Biodiversity Action Plan targets

Statutory / Non Statutory Conservation Targets Drivers UK Biodiversity Action Plan The objectives of the UK National Chalk Rivers Habitat Action Plan are:

 Maintain the characteristic plants and animals of chalk rivers, including their winterbourne stretches.  Restore all rivers notified as SSSI to favourable condition.  Restore important non-SSSI rivers to favourable condition.

There are a large number of other national/Norfolk Habitat and Species Action Plans relevant to the Wensum, including floodplain and coastal grazing marsh, reed-bed, fen, otter, water vole, Desmoulin’s whorl snail, white-clawed crayfish and bat species. All these SAP/HAPs have targets and objectives (www.norfolkbiodiversity.org)

Bearing in mind that both the national and international importance will provide a good level of protection for BAP species and habitats, from a project perspective, this was not felt to be as important to the project, but still needed to be included, so the weight is correspondingly lower. The value of 0.6 was used. Table A.6 lists how UK BAP targets were scored. Table A.6 – UK Biodiversity Action Plan scoring

Compliance with Regional Designation (BAP) Score Description Typical Effect +2 High relevance Direct immediate improvement in designated item. +1 Low relevance Moving towards favourable condition. 0 Neutral No change. -1 Low Detriment Moving away from favourable condition. -2 High Detriment Permanent adverse changes.

A.1.6 Contribution to overall ecology: The non-protected ecology needs to be included to address the Agency’s duty to further conservation. Table A.7 lists those issues/drivers that have been identified as being important to improving overall ecology in the Wensum.

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Table A.7 – Issues identified in this study as being important drivers for restoration

Statutory / Non Statutory Conservation Targets Drivers North Norfolk Natural  Identify and promote flows necessary to sustain Area Profile geomorphological and ecological interest of the system.

 Identify, maintain, enhance, and restore both natural and man- made riverine features which provide ecological and conservation interest.  Ensure protection, enhancement and restoration of habitat features during the design and implementation of flood defence schemes.  Restore arable land adjacent to rivers back to pasture to reduce silt loading and improve habitats.  Manage associated dyke systems on a regular but not intensive regime. Environment Agency  To sustain and where appropriate enhance or restore the habitat diversity within the water environment.  To provide an environmental assessment and recommendations to ensure the maintenance and enhancement of conservation interest to flood defence.  Develop Water Level Management Plans to protect the ecology of sensitive wetlands.  Fisheries Action Plan for the Wensum. European Water  Take appropriate measures to ensure water bodies attain Framework Directive Good Ecological Status by 2015.

 Establish a Programme of Measures to ensure water bodies attain Good Ecological Status. European Habitats  Monitor, assess and enhance favourable condition of SAC Directive rivers.

 Review of consents under Regulation 50 of the Habitats Regulations is another major driver for the Environment Agency and other competent authorities.

UK Gov Public Service  95% of SSSIs by area in favourable or unfavourable Agreement (PSA) recovering condition by December 2010. Targets

Planning Policy  PPS9 sets out the Government’s national policies on Statement 9: protection of biodiversity and geological conservation through Biodiversity and the planning system. Geological Conservation  Plan policies on the form and location of development should take a strategic approach to the conservation, enhancement and restoration of biodiversity and geology. Environmental Higher Level Stewardship applications for environmentally Stewardship Targeting - sensitive farming practice: Mid Norfolk  Maintain or enhance Sites of Special Scientific Interest (SSSIs).  Improvement of water quality through reduction of soil erosion (priority: R. Wensum catchment) and leaching of nutrients. Unit 47 Tatterford Common to Fakenham Mill_Final.docx 153

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Statutory / Non Statutory Conservation Targets Drivers  Conservation of landscape and wildlife associated with arable farming; in particular maintaining locally distinctive landscapes and reversing the decline in farmland birds.  Protection of historic and archaeological sites.  Access – provide further recreational facilities, to promote greater appreciation of the countryside.  Maintenance and restoration of BAP priority habitats.  Conservation of BAP priority and locally important species.

However, again from a project perspective this is not as important so is weighted lower at 0.5. Scoring of this criterion is shown in Table A.8. Table A.8 – Contribution to overall ecology scoring

Contribution to Overall Ecology Score Description Typical Effect +2 High relevance Direct immediate improvement in designated item. +1 Low relevance Moving towards favourable condition. 0 Neutral No change. -1 Low Detriment Moving away from favourable condition. -2 High Detriment Permanent adverse changes.

A.1.7 Project Delivery To deliver the project the RWRS objectives need to be met, and the stakeholders they impact on need to support and promote those objectives. Thus, the criteria within this group can be subdivided into:  RWRS objectives  Stakeholders. The stakeholders for this project naturally fall into 2 groups:  Statutory stakeholders  Non-statutory stakeholders. The definition of statutory stakeholders is straight forward: it is those statutory bodies that are either funding the works or have a legal right to control the outcomes (for example: Environment Agency). Non-statutory stakeholders are those outside of the government bodies who have a legal right to comment and so influence the outcomes (for example: land owners). The outcomes of the RWRS do not stand in isolation because besides impacting on the people in the valley they impact on the wider environment and its use. This is the non ecological environment of the valley which is predominantly of interest to people, so we have termed it:  Human Environment. This gives 4 sub-criteria, and again, in terms of the RWRS these are not equal. The definitions and weightings are explored below.

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A.1.8 Compliance with Strategy Objectives This whole project is about delivering the objectives of the RWRS. This comprises of 2 parts:  The general objectives of the project, as covered in the RWRS Recommendations.  The specific restoration measures for individual reaches as covered in RWRS Appendix A. Clearly this is the most important criterion and so has to have the maximum weighting of 1. Scoring of this criterion is shown in Table A.9. Table A.9 – Compliance with strategy objective scoring

Contribution to Overall Ecology Score Description Typical Effect Immediate and/or full delivery of easily identified +2 High relevance RWRS objective. Enabling or partial delivery of identifiable RWRS +1 Low relevance objective. 0 Neutral No change. Temporary or low level interference with RWRS -1 Low Detriment objective. Immediate and/or full interference of easily identified -2 High Detriment RWRS objective.

A.1.9 Compliance with Statutory Stakeholders This covers the views of those statutory bodies that have a legal and/or financial stake in the success of the project. In probable order of priority, this includes:  Environment Agency  Natural England  Norfolk Rivers IDB  Local authority  Norfolk CC  English Heritage. For the project to be supported to fruition, with the objectives carried forward into the future, the statutory stakeholders will have to feel that the project is a success. This will have to consider views from the wider organisation where there is consultation. Without the support of the statutory bodies the full delivery of RWRS reach objectives will be difficult. This is nearly as important as compliance with the RWRS itself, and so has a weighting of 0.9. Scoring of this criterion is shown in Table A.10.

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Table A.10 – Stakeholder scoring

Compliance with Statutory Stakeholders Score Description Typical Effect +2 High relevance Large majority with favourable view. +1 Low relevance Small majority with favourable view. 0 Neutral No issues. -1 Low Detriment Small majority with concerns. -2 High Detriment Large majority with concerns.

A.1.10 Agreement with Non-statutory stakeholders Non-statutory stakeholders are those outside of the government bodies who have a legal right to comment and so influence the outcomes. This covers, in probable order of importance:  Land owners  Agricultural tenants  Fishery tenants  Householders  Commercial interests. Although the statutory bodies have the ability to impose some aspects of the strategy on the valley, without support of those who own or occupy the land and river the process of implementation would be:  Slow and expensive, due to legal process.  Lacking in richness due to lack of local knowledge informing designs.  Viewed as a failure and so lack long term viability.  Impact on long term relationships with the statutory bodies in everything they do.

This is of importance to the project delivery and so is weighted at 0.9. Scoring of this criterion is shown in Table A.11. Table A.11 – Non-statutory stakeholder scoring

Compliance with Non-statutory Stakeholders Score Description Typical Effect +2 High relevance Large majority with favourable view. +1 Low relevance Small majority with favourable view. 0 Neutral No issues. -1 Low Detriment Small majority with concerns. -2 High Detriment Large majority with concerns.

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A.1.11 Contribution to Human Environment This covers both non-river statutory designations such as:  Archaeology  Town & Country Planning as well as human usage of the river and valley such as:  Angling  Canoeing  Walking & footpaths  Landscape and wider amenity. Although this is the non ecological environment of the valley, it is predominantly of interest to people, so it must be included in the criteria. It is important, but not central to the delivery of the project and so has been given a weighting of 0.4. Scoring of this criterion is shown in Table A.12. Table A.12 – Human environment scoring

Human Environment Score Description Typical Effect +2 High relevance Widespread support. +1 Low relevance Some support. 0 Neutral Indifferent. Some general concern or local concern about small -1 Low Detriment issue. Wide scale concern or strong concern over specific -2 High Detriment local issue.

A.1.12 Technical This criteria group concentrates on the delivery of the RWRS objectives. It is broken down into 4 sub-criteria areas:  Technical feasibility & practicality  Geomorphic form & function  Flood risk  Climate change & sustainability. Each of these deals with particular risks that will vary by reach and by the selected restoration solutions applied at particular locations.

A.1.13 Technical Feasibility & Practicality This item covers:  Feasibility assessment  Engineering design  Construction process  Commercial risk

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 Maintenance liabilities. This is the most important aspect regarding the management of risk in the project, and so is an important technical factor within the technical criteria group. A weighting of 1 has been used. Scoring of this criterion applies and is shown in Table A.13. Table A.13 – Technical scoring

Technical Feasibility & Practicality Score Description Typical Effect +2 High relevance Large benefit with little risk. +1 Low relevance Small overall benefit or lack of difficulty 0 Neutral Average. -1 Low Detriment Some difficulty. -2 High Detriment Little benefit with large risk.

A.1.14 Geomorphic form & function The shape of the river and the flow processes are important for 2 reasons:  The environmental designations specifically mention them, and  It is necessary to understand the processes and the resulting river shape to be able to design any of the restoration options/measures to produce predictable results that sustain into the future. This is therefore important regarding the management of risk in the project, and so has to be an important technical factor within the technical criteria group. A weighting of 1 has been used. Scoring of this criterion is shown in Table A.14. Table A.14 – Geomorphic scoring

Geomorphic Form & Function Score Description Typical Effect Immediately delivers full form and/or mature +2 High relevance processes. +1 Low relevance Kick starts process or provides some form. 0 Neutral No change. Reinforces existing lack of processing at a local -1 Low Detriment scale. Reinforces existing lack of processing or creates -2 High Detriment inappropriate processing anywhere.

A.1.15 Flood risk Flood risk management is one of the Environment Agency’s primary responsibilities, therefore project outcomes cannot increase flood risk to people or properties. This is particularly important on the Wensum as there are 44 properties at risk of flooding, and there are routine maintenance activities to control existing flood risk. Any proposals that impact on water level or flow on statutory Main River require Flood Defence Consent from the Environment Agency, the primary objective of which is to demonstrate no detrimental effects on flood risk.

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This is a significant factor within the technical criteria group and so has a weighting of 1. Scoring of this criterion is shown in Table A.15. Table A.15 - Flood risk scoring

Flood Risk Score Description Typical Effect +2 High relevance Good risk reduction locally and/or elsewhere. +1 Low relevance Some reduction in flood risk anywhere. 0 Neutral No change. -1 Low Detriment Some increase in flood risk anywhere. -2 High Detriment Significant increase in local flood risk.

A.1.16 Climate Change & Sustainability This has been included to ensure that project proposals remain fit for purpose into the future. Current UK guidance on the impacts of climate change on fluvial flooding from the government’s Foresight Report, which has fed into Planning Policy Supplement Note 25 (PPS 25), recommends that an allowance of an extra peak flow of 20% is made, which covers the impact on flood risk change to 2050. Project proposals are viewed against their ability to withstand increased flows without detriment to themselves, the habitat created by them, or flood risk. Clearly a lack of robustness is not very sustainable in its own right. However, given wider concerns, a view on the carbon footprint of proposals is also appropriate. Whilst it is a useful criterion it is not the most important, so a weighting of 0.8 is used. Scoring of this criterion is shown in Table A.16. Table A.16 – Climate change scoring

Climate Change & Sustainability Score Description Typical Effect +2 High relevance Is stable in the short and long term. Is stable in the short term or provides a pre-cursor to +1 Low relevance later works. 0 Neutral No change. -1 Low Detriment Is unstable in the short term or prevents later works. -2 High Detriment Is unstable in the short and long term.

A.1.17 MCA Options 6 major option groups have been identified:  Do nothing  Do minimum  Targeted maintenance  Continue as present  River restoration  Alternative options.

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These are in rough order of increasing intervention with the natural processes. They are briefly described below:

A.1.18 Do nothing As the objective of the strategy is to improve the ecology of the river, which is predicated on the return of natural form and process, this option means:  No maintenance to main river or IDB channels  No restoration to any channels or floodplain  No operational activity A.1.19 Do minimum This is from the view of the RWRS and so means:  Opportunistic restoration, eg. o Securing fallen trees as LWD, o Re-shaping shoals where growth occurs after floods o Re-shaping bank profiles to create berms when bank collapse occurs  No maintenance  No operational activity A.1.20 Targeted maintenance This covers:  Reduced maintenance: reactive in selected critical areas.  Mitigation for activity in form of small scale restoration.  Operational activity; sluice management for high flows. A.1.21 Continue as present This covers existing arrangements:  Planned maintenance: assessed LWD & CWD removal; selected weed cutting and silt removal.  Opportunistic small scale restoration.  Operational activity: sluice management for high flows. A.1.22 River restoration This covers 20 different restoration measures that have been identified for the river. Each of these is assessed for its use on the particular reach being scored. A.1.23 Alternative options There are 3 options that have been considered:  Increased main river maintenance. This includes: o Increased in-channel clearance of silt. o Increased frequency of weed cutting. o Return of channel to “design” dimensions.

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o Maintained timber clearance. o Bank repairs.  Increased main river and IDB channels maintenance. This includes: o As above, plus, o Integrated programme for main river and IDB channels. o Inclusion of IDB channel main river confluences for regular maintenance.  Mills re-use for hydro-power. This includes: o Overall generation of energy through harnessing the kinetic energy of water. o Operational reinstatement of all water level control structures. o Operating protocols for all structures. o Regular channel maintenance around control structures. These options were derived from comments picked up at the ‘drop in’ sessions and represent broad aspirations.

A.2 Use of MCA scorings The use of MCA and the resultant reach scores represents a key part of the design process. The overall process is shown in table A.17 as follows: Table - A.17 - SSSI Designation targets

A Constructing the MCA Tool 1 Identification of options/measures. 2 Selection of success criteria. 3 Ranking of success criteria using weightings. 4 Setting up the MCA table. B Applying The MCA Tool (Spreadsheet) to Specific Reaches 1 Is the option/measure applicable to the reach? If no, discard. 2 Work through each criterion by option/measure. 3 Apply weighting and determine total weighted score (TWS) 4 Discard all options/measures with zero or negative scores. 5 Mill structure measures: Apply the best scoring measure. Other measures: Undertake statistical analysis and discard measures scoring 6 below lower limit. Other measures: Apply remaining measures in order of highest to lowest 7 scoring. 8 Gravel works: Apply best scoring measure.

A.2.1 Note on statistical approach The options need to be checked for importance to see which ones are truly important and which ones are not. This has been determined by calculating which options have a TWS outside of one standard deviation either side of the mean. This was chosen as it is a standard measure of dispersion. Those with a value greater than the sum of the mean plus the standard deviation are of high importance: those with a value less than the sum of the mean minus the standard deviation are of low importance. Those of low importance represent those options that could easily turn negative were only a few criteria to get more harshly re-appraised: those of high Unit 47 Tatterford Common to Fakenham Mill_Final.docx 161

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importance are those that are very robust, and so represent the minimum options that should be carried out on any reach.

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Appendix B - Costings

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B.1 COST DETAILS To generate the cost estimate for Unit 47, a certain number of assumptions have been made:  General assumptions that apply to all measures; and  Specific assumptions that apply to particular measures B.1.1 General assumptions The following costs have not been taken into account: 1. Significant works to address site access issues (haul roads, tracks etc). 2. Works relating to unforeseen ground conditions and ground investigation costs. 3. Allowances for landowner compensation or accommodation works. 4. Phase I habitat surveys and ecological mitigation works. 5. Utility searches. 6. Contractors general Items/Insurances. 7. Detailed design. 8. Permissions, consents and consultation related costs. 9. Project specific risks. The cost estimates has been derived using assumptions appropriate for the level of detail necessary for concept design. These estimates allow comparison of costs between other conceptual designs undertaken for individual river units.

B.1.2 Specific Assumptions Fencing Fencing costs are summarised in Table B.1 below. The following assumptions apply: 1. The fencing used is assumed to be simple livestock fencing: - 100mm diameter tanalized timber posts driven at 3m centres, - 3 barbed wires at 1.2m, 0.8m and 0.4m. 2. Fencing lengths assume that only one side of the river bank for each reach (except Reach 26 where no fencing will be required and Reach 31 where both sides are to be fenced). This is to satisfy landowner requirements and bank protection needs.

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Table - B.1 - Total estimated costs for berm creation for Unit 47

Reach Reach Length Assumed Fencing Length (m) (m) 26 464 (no fencing) 0 27 1720 1720 28 1245 1245 29 2630 2630 30 665 665 31 475 (either side) 950 Total Length: 7210 Rate for supply and installation £/m 4 Cost for Unit: £28,840

Berm Creation Berm costs are summarised in Table B.2 below. The following assumptions apply: 1. Low level berms will be constructed below 1/2 bank height, on the inside of existing bends, to increase sinuosity of the channel. 2. A total of 32 bends are recommended for an average of 21m each as indicated on Figures 6.1 to 6.3. 3. Construction activities consist of removing vegetation for re-use; staking the new alignment with hardwood posts at 0.75m centres; placing double height coir rolls against the stakes; backfilling with local material to blend height to local berm heights; replace vegetation. 4. The bioengineering revetment is to be cut back into the existing bank material to stop outflanking. This will require and overall length of 1/3 of berm lengths.

Table - B.2 Total estimated costs for berm creation for Unit 47

Reach No. Bends Bermed Berm Length (m) Total Length (m)

26 18 21 378 27 3 21 63 28 11 21 231 29 - - - 30 - - - 31 - - - Unit total (m) 672 Rate £90/m 90 Cost for Unit: £60,480

Channel Re-sectioning Channel re-sectioning costs are summarised in Table B.3 below. The following assumptions apply: 1. Re-sectioning is recommended for one reach totalling 60m in length.

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2. Re-sectioning assumes simple excavation work to the upper bank. 3. Depth of excavation will depend on local conditions, but should not be lower than existing self-formed berms; otherwise it will cause instability under flood flows as it will expose the softer material at the landward end of the berm. For the purpose of the cost estimates, 1/2 channel height has been assumed. 4. The river edge vegetation is to be retained for re-use on the berm, and bank top vegetation and topsoil re-used on the rear slope of the berm to provide protection. 5. Rear slope to the berm to be at a self-stable angle of recline, and certainly no steeper than 1:2. 6. Width of the berm will depend on local conditions, but does not need to be wider than ½ existing channel top width from hard bank edge to middle of rear slope. 7. Length of berm along the river will depend on local conditions; primarily the proximity of other features. 8. It is assumed that arisings will be transported and spread within 100m of the works, and outside of the floodplain. 9. The arisings have the potential to be used in the construction of other features.

Table B.3 - Total estimated costs for excavation associated with re-sectioning for Unit 47

Reach Length Channel Nom. Channel Nom. Nom. (m) top width Width depth Depth Volume (m) (m) (m) (m) (m3) 26 - 27 - 28 60 6.35 3.175 1.32 0.66 125.73 29 - 30 - 31 - 3 Unit Volume: (m ) 125.73 3 Excavation: reduce level <1m. (Rate:£/m ) 9.83 3 Dispose spoil 100m from excavation. (Rate:£/m ) 4.35 Cost for Unit: £1,783

Tree Felling Tree felling costs are summarised in Table B.4 below. The following assumptions apply: 1. Qualified arborists can typically trim, control and fell 4 riverside trees (approximately 50 years old) over 50m of river, in a day. 2. Tree felling is required along the banks of 860m of river. 3. Cost per day for a team of two qualified arborists to trim, control fell is assumed to be £500. This assumes 4 trees (approximately 50 years old) over a distance of 50m can be felled in one day. Costs include cording the wood for log piles, or trimming and cutting

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trunks for re-use. Costs do not include any transport or movement of timber once felled. Tree felling costs are taken as £10/m of river.

Table B.4 - Total estimated costs associated with tree felling for Unit 47

Reach Length (m)

26 110 27 200 28 560 29 - 30 100 31 - Length in unit: 970 Rate: (£/m) 10 Cost for Unit: £9,700

Backwater reconnection Backchannel reconnection costs are summarised in Table B.5 below. The following assumptions apply: 1. Backchannel reconnection assumes simple excavation to connect existing channels with the river excavating a total of 450m with no bank or bed protection. 2. To provide an appropriate size of channel, and stable bank profile, it has been assumed that the bed width of the excavation will be equivalent to river height, and the top width will be 3 times the river height. This will provide 1:1 side slopes, which matches natural bank angles. 3. Backchannel reconnection works would also need to include appropriate works to re-form the backchannel to enhance stability and habitat delivery. Typically this could consist of re-sectioning and removing encroaching silt and vegetation within the channel. 4. Reconnection at the downstream end will be excavation down to river bed level; reconnection at the upstream end will be by excavation down to the backchannel bed level, post any clearance / re-forming works. 5. Bank protection works beyond re-placing vegetation turfs are not taken into account in the rates. Any further works will be dependent on local conditions found during detailed design investigations.

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Table B.5 - Total estimated costs associated with backchannel reconnection for Unit 47

Reach Exc. Length River Depth Nom. Volume Cost (m) (m) Section (m3) (m2) 26 0 - 27 180 1.76 6.20 1115.14 £15,813 28 120 1.32 3.48 418.18 £5,930 29 150 1.2 2.88 432 £6,162 30 0 - 31 0 - 3 Unit Rate of excavation (£/m ) 9.83 3 Dispose spoil 100m from excavation. (Rate:£/m ) 4.35 Cost for Unit: £27,869

Gravel Glides Gravel glide costs are summarised in Table B.6 below. The following assumptions apply: 1. Cost is directly dependant on volume placed. 2. Gravel glides dimensions vary according to location as indicated in the Table B.6 below. 3. Gravel glides have been dimensioned using channel size dimensions provided in the 2007 JBA report. Width of channel used has been taken as the ‘erodible bank width’ as it is representative of the realistic width of erosion, and therefore needs protection. The depth of gravel used is the amount identified as needed to raise the bed. The length of the glide is taken as 3 times the resistant bank width to ensure that ‘edge effects’ are controlled, so that these artificial glides more closely match those observed, and will realistically fit between the existing bends. 4. The long section through the glide assumes a 1:1 slope at the upstream and downstream ends to give some stability. This has been allowed for in the volume per glide. 5. The rate for supply and placement of gravel is based on a material supply cost of £27/tonne for 20-50mm gravel rejects and a placement cost of £4.85/m3. At 1.78t/m3 the gravel supply rate equates to £48.06/m3, which combined with the placement rate gives an overall rate of £53/m3.

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Table B.6 Total estimated costs associated with installing gravel glides for Unit 47

Reach Bed Erodible Resistant Length Volume Number Volume Raising width (m) Width (R) 3 x R (m) per glide of Glides per Reach Required (m) (m3) (m) 26 1.4 6.8 4.5 13.5 142.8 9 1,276.6 27 1.4 6.7 4.4 13.2 136.9 12 1,643.4 28 0.4 6.35 4.2 12.6 33.0 8 264.2 29 0.5 6.2 4.15 12.45 40.1 6 240.9 30 0.75 3.55 2.35 7.05 20.8 7 145.4 31 - - 3 Volume for Unit: (m ) 3,570.4 3 Rate for supply and placement (£/m ) 53 Cost for Unit: £189,231

Channel realignment: Channel realignment costs are summarised in B.7 below. The following assumptions apply: 1. Excavation will be to the full height of the riverbank from bank top to river bed; unlike re- sectioning which is 1/2 height excavation. 2. Unlike other excavation based measures, the spoil arisings from this operation are assumed to be re-used locally to in-fill the channel from the far bank. 3. Realignment assumes the bank is re-aligned by the equivalent of a natural channel width. It is also assumed that the bank is cut at a stable angle of recline, and that no protection works are carried out to allow natural processes to prevail. 4. Channel realignment is recommended at two reaches for a total length of 750m.

Table B.7 - Total estimated costs associated with channel realignment for Unit 47

Reach No. Length Channel Channel Volume Rate Cost Locations per Width Height (m3) Location (m) (m) (m) 26 - 27 - 28 1 350 3.35 0.75 879.4 9.83 £8,644 29 - 30 1 400 3.55 0.72 1022.4 9.83 £10,050 31 - Cost for Unit: £18,694

Deflector Deflector costs are summarised in Table B.8 below. The following assumptions apply: 1. It is assumed that these are created from large woody debris (LWD) won locally and where possible from tree felling activities.

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2. A deflector group consists of 3 deflectors pointing upstream; spaced at natural channel width along the bank to affect an area equivalent to 3 times natural channel width. The length of the deflector is determined locally so as to mobilize silts and suit channel width. 3. The deflectors consist of clean timber tree trunks alternately staked and wired to hardwood stakes at 1m centres. The butt end is embedded into the bank by 2m or one third length whichever is the shortest. The trunks are to be laid on shorter faggot bedding. 4. Deflector height to be no higher than high summer water level so that it can drown out under higher flows. 5. Deflectors are recommended for 11 locations in this unit.

Table B.8 - Total estimated costs associated with implementing deflectors for Unit 47

Reach No. of Groups Length per Reach (m) 26 0 - 27 4 53 28 5 63 29 - 30 2 14 31 - Total for Unit: 130 Rate per length of river: (£/m) 44 Cost for Unit: £5,720

Tree planting Tree planting costs are summarised in Table B.9 below. The following assumptions apply:

1. Tree species are assumed to be appropriate native riverside species such as: alder, black poplar, and willow. The black poplar needs to be from a certified source (and of Norfolk provenance) as they hybridize readily. 2. Tree planting consists of a group of 10 individual trees at specific locations to create shade and bank reinforcement. Tree group planting is recommended in 14 locations. Planting areas to run on average for 10m along the bank length. 3. Planting costs include: supply of 2-3m standard; planting; tube, stake and tie and deer proof enclosure. Total costs estimated cost per tree is £58. 4. Cost for planting a tree is estimated on team of two (£500/day) capable of planting 3 trees per hour over 7 hours. 5. An allowance for machinery access to control density of shading is required. It is suggested that a minimum of 4m distance is maintained between the fence line and the trees.

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Table B.9 - Estimated tree costs

Item Cost Supply 2-3m standard tree £10 Plant tree £23 Supply & install: tube, stake, ties £1 Deer proof enclosure £24 Total per tree: £58

Table B.10 - Estimated costs for new tree planting

Reach No. of Locations No. Trees 26 0 - 27 4 40 28 0 - 29 0 - 30 5 50 31 5 50 Total: 140 Rate: £58 Cost for Unit £8,120

Plugs in main channel Plugs construction costs are summarised in Table B.11 below. The following assumptions apply: 1. Plugs are constructed using gravel rejects. 2. Upstream and downstream slopes are constructed at a 1:1 slope. 3. The height of the plug assumes current channel depth. 4. The width of the plug is based on JBA’s 2007 estimated channel depths.

5. The length of the plug is assumed to be three times the target erodible bank width.

Table B.11 - Estimated costs for plugs

Reach Channel Depth Nominal Length of plug Nominal Cost Width Section (m) volume (m2) (m3) 26 27 16 1.76 28.16 20.1 566.0 £29,999 28 - 29 - 30a 12 1.46 17.52 10.65 186.6 £9,899 30b 12 1.46 17.52 10.65 186.6 £9,899 31 Rate (£/m3) £53.00 Cost for Unit £8,120 £49,777

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Other restoration measures Other restoration measures in Unit 47 refer to lowering spoil embankments. Construction costs for this measure is summarised in Table B.12 and B10 below, respectively. Table B.12 - Estimated costs for lowering spoil embankments in Unit 47

Max height Reach volume Reach Length (m) Max width (m) (m) (m3)

26 - -

27 100* 3 1 300

28 - -

29 - -

30 - -

31 - -

Unit volume 300

Earth movements cost (£) 9.83

Total for unit (£) £2,949 * Approximated for reach extent

B.1.3 Summary Costs for recommended restoration measures for Unit 47 Table B.13 - Estimated costs per unit length applied Measure: Description Quantity Rate per Cost unit 5.1 Fencing (m) 7,210 4 £28,840 5.16 Berm creation (m) 672 90 £60,480 5.15 Channel re-sectioning (m3) 125.73 14.18 £1,783 5.12 Tree felling (m) 970 10 £9,700 5.17 Backchannel – reconnection (m3) 1,965.3 14.18 £27,868 5.7g Gravel glides (m3) 3,570.4 53 £189,231 5.19 Channel realignment (m3) 1,901.8 9.83 £18,694 5.13 Deflector (m) 130 44 £5,720 5.11 Tree planting (unit) 140 58 £8,120 Plugs (m3) 939.2 53 £ 49,777 5.14 Lower spoil embankment (m3) 300 9.83 £2,949 Option G3 Targeted Maintenance - Unknown - Total: £403,162

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Table B.14 - Comparison of costs between 2007, 2008 and 2010 studies Halcrow (2008a) JBA (2007) Atkins (Sept 2011) Length Cost Length Cost Length Cost (km) (£) (km) (£) (km) (£) Fencing* 0 0 4.8 £31,734 7.2 £28,840 Large woody debris 0.36 £ 7,000 0.13 £5,720 In-stream structures 0.36 £29,000 0.04 £49,777 Cross section modifications 2.16 £129,000 4.8 £1,055,600 1.6 £83,906 Bed raising 2.16 £332,000 6.1 £1,090,620 0.5 £189,231 Landscape** - 4.8 £5,289 2.3 £17,820 Reconnections - 0.5 £27,868 Restoration 0.5 - Structure modification £704,000 £500,000 Totals: 5.04 £1,201,000 16.19 £2,758,243 5.07 £403,162 Overall Unit rate: £/km £166,829 £383,143 £55,995 Density of features 0.70 2.25 0.70 Density adjusted rate £116,780 £861,499 £39,196 £/km Notes: *Fencing length excluded from the calculation of the total length of restoration features. **Includes tree felling and tree planting

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Appendix C – Ecology tables

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C.1 River Wensum SSSI/SAC: Status, ecology and habitat requirements of European interest features

Species / community Designations and status General ecology Habitat requirements Habitat requirements (continued)

Brook lamprey Listed in annexes IIa and Va of the Habitats Brook lamprey have both a sedentary larval Ammocoete larvae Adult lamprey (Lampetra planeri) Directive, Appendix III of the Bern (ammocoete) stage and an adult dispersal Substrate Adult spawning grounds Convention, and as a Long List Species in phase, during which spawning takes place. Ammocoetes occur in suitable silt beds, mainly in running water but Spawning grounds are located in areas of the UK Biodiversity Action Plan. They do not feed as adults and hence spawning sometimes in large numbers in silt banks in lakes. Preferred small stones and gravel in flowing water, is generally considered to be preceded by a substrate varies in depth from a few cm to 30 cm and is generally with spawning often occurring at lower The most common of the 3 British lampreys relatively short migration to the spawning areas. composed of mud, silt, or silt and sand with a high organic content ends of pools. The spawning gravels are occurring over much of the British Isles. Brook lamprey tend to undertake small upstream (optimum particle size 80–380 μm). Larval nursery beds are often composed of stones up to 3 in. with good Absent from much of Scotland north of the migrations prior to spawning during which time located at the edges of streams and rivers, well away from the main permeability, although smaller Great Glen. they continue to burrow like ammocoetes or hide current in flowing backwater sections. consolidating particles are required. under stones during the day. The extent of the Stones embedded in fine sands or silts migration depends on stream gradient which Water quantity and quality which form a hard bed are often avoided. may also impact upon the distance ammocoetes Flow rates of 0.5 m s-1 at the water surface, and 0.4 m s-1 at a The nest, which may be constructed by up drift downstream during development, as well as depth of 25 cm have been observed above nursery beds and flows to a dozen or more adults, is normally an spawning habitat availability. After spawning has of 8–10 cm s-1 have been recorded over Lampetra burrows. oval depression about 20–40 cm across occurred, newly hatched larvae leave the nest and 2–10 cm deep. and distribute themselves by drifting Water quantity and quality downstream and burrowing in suitable areas of The brook lamprey is regarded as being silty sand. sensitive to pollution requiring at least UK Water Quality Class B (EA classification) Life-cycle in all parts of any river where brook Metamorphosis July to September lamprey life stages occur. At spawning Spawning migration November to February sites flow velocities of 30–50 cm s-1 have Spawning March to April (10-11oC) been noted. Bullhead (Cottus In the UK the native range of Cottus gobio Common species of the headwaters of many Bullhead habitat requirements are dependent on life stages. Coarse Substrate gobio) is restricted to England and Wales, types of upland and lowland river where it is benthic substrates with large stones are required for breeding and Benthic gravel and stones substrates are although some introduced populations are associated with stony benthic habitats with shallow riffles and glides are utilised by YOY (young of year) fish. a vital habitat requirement for bullheads established in Scotland. moderate flow. Also occasionally found in lakes. Adults appear to prefer sheltered sections created by woody debris, as they provide both spawning habitats Listed in annexes IIa and Va of the Habitats Benthic macroinvertebrates such as Gammarus tree roots, leaf litter, macrophyte cover or large stones and all life and refuges against flow and predators. Directive, Appendix III of the Bern and Asellus, together with aquatic fly larvae are stages require slack-water refuges during spate flows. Bullheads will also utilise macrophytes as Convention. the dominant prey items. Habitat H3260 ‘Rivers refuges from predators and flows if large with Ranunculion fluitantis and Callitricho- Water quantity stones are a limiting factor. If gravel and batrachion vegetation’ is a key habitat for this Water depth is not critical providing it is >5 cm and flow is stone substrates are not limiting within the species in the UK. adequate. High temperatures or low dissolved oxygen may be fatal stream, bullheads will also associate with in shallow water, because temperature fluctuations are greater. depositional habitats such as pools Spawning occurs from February to July with the Typically, bullhead are found in depths of 20 to 40cm. containing woody debris. male excavating a nest under a suitable large stone to attract a female. Bullheads may use Water quality Channel structure other media such as woody debris or tree roots. Some tolerance to organic pollution (ammonia) and heavy metals is Natural channel forms exhibiting riffle/pool The female lays a batch of up to 400 eggs (2– exhibited where oxygen saturation remains high. The bullhead’s sequences provide appropriate substrate 2.5 mm in diameter), which adhere to the sympatric occurrence with brown trout indicates a requirement for and flow character for bullhead, as a underside of the stone. The male defends the oxygen concentration of 40% saturation and critical thermal limits of result supporting higher densities than brood against predators and maintains water – 4.2 and 27.7°C have been described. heavily modified channels. circulation by fanning the eggs. Eggs hatch after Filamentous algal growth resulting from eutrophication is Riparian trees are known to provide 20 to 30 days and after 10 days the fry (9 mm in detrimental where algae covers the favoured coarse, hard substrate shade and shelter as well as valuable length) disperse, colonising newly available (see below) and influence food-web dynamics. input of woody debris and leaf litter. habitat downstream including temporary channels, and floodplain lakes.

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Species / community Designations and status General ecology Habitat requirements Habitat requirements (continued)

Desmoulin’s whorl Desmoulin’s whorl snail is listed under Desmoulin’s whorl snail lives in permanently Water level requirements snail (Vertigo Annex II of the European Union Habitats wet, usually calcareous, swamps, fens and Hydrology is a factor determining the distribution of the Desmoulin’s moulinsiana) and Species Directive. It is a priority marshes, bordering rivers, lakes and ponds, or whorl snail with high groundwater levels throughout the year being species in the UK Biodiversity Action Plan in river floodplains. It is most often found in open one of the most important factors. Maximum snail densities are (HMSO 1996) and is listed in the British situations associated with the following often located where water levels are continuously above the ground Red Data Book (Bratton 1991) as an RDB3 vegetation: surface throughout the year, and where mean annual water levels (Rare) species. • Reed sweet grass (Glyceria maxima) are more than 0.25 m above the surface. • Sedges (Carex riparia, C. acutiformis, C. Annual fluctuations of between about 0 m and 0.6 m above ground Scattered sites across southern England paniculata, C. elata) level provide optimum conditions with summer water level critical from Norfolk to Dorset, with isolated • Saw sedge (Cladium mariscus) thresholds estimated to be at 0.5 m below surface ground level. populations elsewhere. Southern chalk • Reed (Phragmites australis) streams have been shown to be as • Reedmace (Typha latifolia and T. angustifolia) Humidity important as the East Anglian fens as • Branched bur reed (Sparganium erectum) Humidity is important since the snail spends much of the year strongholds for this species. • Iris (Iris pseudacorus) climbing in the canopy of the vegetation well away from the ground. • Reed canary grass (Phalaris arundinacea) Humidity regimes are likely to be influenced by vegetation structure, Adjacent to rivers, its presence/absence and which is clearly affected by management. population density are largely determined by the structure and topography of the banks and the nature of the riparian management. The most suitable riparian habitats comprise a relatively broad strip where Glyceria or Sparganium spp. form dense floating rafts on gently sloping banks. Steeper banks as a result of canalisation, impounding, channel dredging, and weed cutting reduces habitat development often resulting in the absence of the snail. 3260 Water courses of Sub-type 1 rivers on chalk substrates. The Characterised by the abundance of water- Ranunculus follows a four phase cycle of biomass development: plain to montane levels community is characterised by pond water- crowfoots Ranunculus spp., subgenus • Regrowth phase in autumn triggered by the seasonal increase in with the Ranunculion crowfoot Ranunculus peltatus in spring-fed Batrachium (Ranunculus fluitans, R. penicillatus flow. fluitantis and headwater streams (winterbournes), stream ssp. penicillatus, R. penicillatus ssp. • Extension phase over winter to April. Rapid increase in biomass Callitricho-Batrachion water-crowfoot R. penicillatus ssp. pseudofluitans, and R. peltatus and its hybrids). with the development of long streamers in spring. vegetation pseudofluitans in the middle reaches, and They may modify water flow, promote fine • Consolidation and flowering phase over late spring to summer. river water-crowfoot R. fluitans in the sediment deposition, and provide shelter and • Biomass production increases then slows as energy is invested in downstream sections. Ranunculus is food for fish and invertebrate animals. flowers and seeds. typically associated in the upper and middle Ranunculus communities are associated with • Decline phase over late summer to autumn. reaches with Callitriche obtusangula and C. assemblages of other aquatic plants e.g. platycarpa. Rorippa nasturtium-aquaticum, Callitriche spp., Sium latifolium and Berula erecta, Myriophyllum Flow Sub-type 2: This variant is found on other spp. and Myosotis scorpioides. The cover of Velocity and discharge are prime factors due to the high substrates, ranging from lime-rich these species may exceed that of Ranunculus photosynthetic rate of Ranunculus: fast flows are required to deliver substrates such as oolite, through soft species. Three main sub-types are defined by oxygen and carbon to the plant. Velocity also acts indirectly to sandstone and clay to more mesotrophic substrate and the dominant species within the remove potentially competitive or shading algae, and clearing silt and oligotrophic rocks. Ranunculus community. from gravels. 0.3 – 0.5 ms-1 optimal summer velocity band. It is recognised that Sub-type 3: This variant is a mesotrophic to Ranunculus growth can occur above the threshold of 0.5 ms-1 but oligotrophic community found on hard rocks is subject to mechanical stresses. in the north and west. Substrate Clean gravel river beds encourage Ranunculus root development and prevent the development of other algal growth which is given an advantage on soft, silty substrates.

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Species / community Designations and status General ecology Habitat requirements Habitat requirements (continued)

White-clawed crayfish Listed under annexes II and V of the EU Crayfish distribution is influenced by geology, Water quality (Austropotamobius Habitats Directive and Appendix II of the requiring relatively hard, mineral-rich waters of The majority of records for the white-clawed crayfish occur in UK pallipes) Bern Convention. Protected under calcareous catchments. The species occurs in a Environment Agency General Quality Assessment Class A and B Schedule 5 of the variety of habitats including canals, streams, waters, an indication of their association with unpolluted fluvial Wildlife and Countryside Act (1981). Priority rivers, lakes, reservoirs and water-filled quarries. systems. The white-clawed crayfish is principally found in alkaline species under the UK Biodiversity Action waters for which calcium and pH requirements are: Plan with its own Species Action Plan. It is typically found in watercourses of 0.75 m to • calcium (5 mg l-1 minimum) 1.25 m deep, but is also found in small streams • pH (6.5–9.0) Austropotamobius pallipes is widespread in (about 5 cm of water) and in deeper, slow- most parts of England and is common in flowing rivers (2.5 m). In flowing water the BOD parts of eastern Wales. It is present in white-clawed crayfish may be found associated The white-clawed crayfish is particularly susceptible to acute south-west Northern Ireland. A significant with: pollution incidents caused by spills of organic material with a high part of the EU resource is found in the UK, biochemical oxygen demand (BOD), such as cattle slurry or silage. but the species is now seriously threatened • Undermined, overhanging banks. over most of its range in Britain. • Sections exhibiting heterogeneous flow Turbidity and siltation patterns with refuges. Gills are easily clogged by sediment and this may cause physico- • Under cobbles (juveniles) and rocks in riffles, pathological changes in the long term. White-clawed crayfish tend and under larger rocks in pools. to avoid substrates covered in mud or silt unless they are actively • Among roots of woody vegetation, foraging for food. accumulations of fallen leaves and boulder weirs. Vegetation • Under water-saturated logs. White-clawed crayfish utilise aquatic macrophyte vegetation for cover and food. They may be found amongst Cladophora spp; The white-clawed crayfish is primarily Fontinalis spp.; or vascular plants such as water crowfoot and carnivorous, feeding on aquatic watercress. Their association with such vegetation may be due to macroinvertebrates and carrion. In addition, their foraging and is particularly important in shallow water habitats allochthonous material in the form of dead as they provide protection from predation and high flows. leaves may provide an important source of food.

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C.2 Potential impacts of mill modification on European interest features of the River Wensum SSSI/SAC

Mill structures Species / community Improve operability + Remove flow control Lower mill sill levels Bypass channels Fish passes Remove all protocols mechanisms

Brook lamprey Due to the range of options Due to the range of options Due to the range of Positive Positive Positive (Lampetra planeri) available under this measure available under this measure options available under Reduction of habitat Reduction of habitat Reduction of habitat severance and increase in assessment of the potential assessment of the potential this measure assessment severance and increase in severance and increase in available habitat for existing lamprey populations. positive/negative effects on positive/negative effects on the of the potential available habitat for existing available habitat for existing Reduction in vulnerability of populations to the ecological feature cannot ecological feature cannot be positive/negative effects lamprey populations. lamprey populations. anthropogenic disturbance through increase in extent be commented on at this commented on at this point. on the ecological feature Reduction in vulnerability of Reduction in vulnerability of of available habitat. point. cannot be commented on populations to populations to anthropogenic Improved ammocoete dispersal and adult migration Review of effects to be at this point. anthropogenic disturbance disturbance through increase through removal of potential barriers. Review of effects to be determined on a site-by-site through increase in extent in extent of available habitat. Increase in available habitat for all life stages. determined on a site-by-site basis following establishment Review of effects to be of available habitat. Improved ammocoete basis following establishment of options and resultant determined on a site-by- Improved ammocoete dispersal and adult migration Negative of options and resultant changes to physical habitat site basis following dispersal and adult through removal of potential Removal of barrier previously preventing colonisation changes to physical habitat e.g. flow, sediment dynamics. establishment of options migration through removal barriers. by competitive/damaging species. e.g. flow, sediment and resultant changes to of potential barriers. Increase in available habitat dynamics. physical habitat e.g. flow, Increase in available for all life stages. Design recommendations sediment dynamics. habitat for all life stages. Provision of appropriate flow velocities to ensure Negative passage is not limited to more active swimming Negative Increased connectivity species. Increased connectivity allowing colonisation of allowing colonisation of reaches by reaches by competitive/damaging competitive/damaging species. species. Design recommendations Design recommendations Provision of appropriate flow Provision of appropriate velocities to ensure passage flow velocities to ensure is not limited to more active passage is not limited to swimming species. more active swimming species.

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Species / community Improve operability + Remove flow control Lower mill sill levels Bypass channels Fish passes Remove all protocols mechanisms

Bullhead (Cottus Due to the range of options Due to the range of options Due to the range of Positive Positive Positive gobio) available under this measure available under this measure options available under Reduction of habitat Reduction of habitat Reduction of habitat severance and increase in assessment of the potential assessment of the potential this measure assessment severance and increase in severance and increase in available habitat for existing bullhead populations. positive/negative effects on positive/negative effects on the of the potential available habitat for existing available habitat for existing Reduction in vulnerability of populations to the ecological feature cannot ecological feature cannot be positive/negative effects bullhead populations. bullhead populations. anthropogenic disturbance through increase in extent be commented on at this commented on at this point. on the ecological feature Reduction in vulnerability of Reduction in vulnerability of of available habitat. point. cannot be commented on populations to populations to anthropogenic Improved dispersal and adult migration through Review of effects to be at this point. anthropogenic disturbance disturbance through increase removal of potential barriers. Review of effects to be determined on a site-by-site through increase in extent in extent of available habitat. Increase in available habitat for all life stages. determined on a site-by-site basis following establishment Review of effects to be of available habitat. Improved dispersal and adult basis following establishment of options and resultant determined on a site-by- Improved dispersal and migration through removal of Negative of options and resultant changes to physical habitat site basis following adult migration through potential barriers. Removal of barrier previously preventing colonisation changes to physical habitat e.g. flow, sediment dynamics. establishment of options removal of potential Increase in available habitat by competitive / damaging species. e.g. flow, sediment and resultant changes to barriers. for all life stages. dynamics. physical habitat e.g. flow, Increase in available Design recommendations sediment dynamics. habitat for all life stages. Negative Provision of appropriate flow velocities to ensure Increased connectivity passage is not limited to more active swimming Negative allowing colonisation of species. Increased connectivity reaches by allowing colonisation of competitive/damaging reaches by species. competitive/damaging species. Design recommendations Provision of appropriate flow Design recommendations velocities to ensure passage Provision of appropriate is not limited to more active flow velocities to ensure swimming species. passage is not limited to more active swimming species.

Desmoulin’s whorl Due to the range of options Due to the range of options Due to the range of n/a n/a Review of effects to be determined on a site-by-site snail (Vertigo available under this measure available under this measure options available under basis following establishment of options and resultant moulinsiana) assessment of the potential assessment of the potential this measure assessment changes to physical habitat e.g. flow, sediment positive/negative effects on positive/negative effects on the of the potential dynamics. the ecological feature cannot ecological feature can be positive/negative effects be commented on at this commented on at this point. on the ecological feature point. can be commented on at Review of effects to be this point. Review of effects to be determined on a site-by-site determined on a site-by-site basis following establishment Review of effects to be basis following establishment of options and resultant determined on a site-by- of options and resultant changes to physical habitat site basis following changes to physical habitat e.g. flow, sediment dynamics. establishment of options e.g. flow, sediment and resultant changes to dynamics. physical habitat e.g. flow, sediment dynamics.

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Species / community Improve operability + Remove flow control Lower mill sill levels Bypass channels Fish passes Remove all protocols mechanisms

3260 Water courses of Reduction in impoundment Reduction in impoundment will Reduction in Reduction in impoundment n/a Reduction in impoundment will result in improved plain to montane levels will result in improved flow result in improved flow regime impoundment will result in will result in improved flow flow regime for Ranunculus communities. Review of with the Ranunculion regime for Ranunculus for Ranunculus communities. improved flow regime for regime for Ranunculus effects to be determined on a site-by-site basis fluitantis and communities. Review of Review of effects to be Ranunculus communities. communities. Review of following establishment of options and resultant Callitricho-Batrachion effects to be determined on a determined on a site-by-site Review of effects to be effects to be determined on changes to physical habitat e.g. flow, sediment vegetation site-by-site basis following basis following establishment determined on a site-by- a site-by-site basis dynamics. establishment of options and of options and resultant site basis following following establishment of resultant changes to physical changes to physical habitat establishment of options options and resultant habitat e.g. flow, sediment e.g. flow, sediment dynamics. and resultant changes to changes to physical habitat dynamics. physical habitat e.g. flow, e.g. flow, sediment sediment dynamics. dynamics.

White-clawed crayfish Due to the range of options Due to the range of options Due to the range of Positive Positive Positive (Austropotamobius available under this measure available under this measure options available under Reduction of habitat Reduction of habitat Reduction of habitat severance and increase in pallipes) assessment of the potential assessment of the potential this measure assessment severance and increase in severance and increase in available habitat for existing white-clawed crayfish positive/negative effects on positive/negative effects on the of the potential available habitat for existing available habitat for existing populations. the ecological feature cannot ecological feature cannot be positive/negative effects white-clawed crayfish white-clawed crayfish Reduction in vulnerability of populations to be commented on at this commented on at this point. on the ecological feature populations. populations. anthropogenic disturbance. point. cannot be commented on Reduction in vulnerability of Reduction in vulnerability of Improved dispersal through removal of potential Review of effects to be at this point. populations to populations to anthropogenic barriers. Review of effects to be determined on a site-by-site anthropogenic disturbance. disturbance. Increase in available habitat for all life stages. determined on a site-by-site basis following establishment Review of effects to be Improved dispersal through Improved dispersal through basis following establishment of options and resultant determined on a site-by- removal of potential removal of potential barriers. Negative of options and resultant changes to physical habitat site basis following barriers. Increase in available habitat Removal of barrier previously preventing colonisation changes to physical habitat e.g. flow, sediment dynamics. establishment of options Increase in available for all life stages. of reaches by competitive and damaging species e.g. e.g. flow, sediment and resultant changes to habitat for all life stages. signal crayfish. dynamics. physical habitat e.g. flow, Negative sediment dynamics. Negative Removal of barrier previously Removal of barrier preventing colonisation of previously preventing reaches by competitive and colonisation of reaches by damaging species e.g. signal competitive and damaging crayfish. species e.g. signal crayfish.

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C.3 Potential impacts of gravel works on European features of the River Wensum SSSI/SAC

Gravel works Species / Gravel glides Gravel glides + transverse hurdles Bed raising (large scale) community

Brook lamprey Positive Positive Positive (Lampetra planeri) Provision of suitable spawning habitat for adult brook lamprey. Provision of suitable spawning habitat for adult brook lamprey as a Significant increase in the extent of suitable spawning habitat for adult Improvement to local water quality through turbulent flow and result of gravel installation. brook lamprey. resultant increase in DO concentration. Hurdle construction will promote deposition of fine sediment Improvement to local water quality through turbulent flow and resultant DO favouring ammocoete life stages. concentration. Negative Improvement to local water quality through turbulent flow and Small scale loss of silt bed areas suitable for ammocoete resultant DO concentration. Negative development. Potential for large scale loss of silt bed areas suitable for ammocoete Potential to cause damage to existing populations during gravel Negative development. placement. Small scale loss of silt bed areas suitable for ammocoete Potential to cause damage to existing populations during installation of bed development at site of gravel placement. raising measures. Design recommendations Potential to cause damage to existing populations during gravel Provision of suitably sized spawning substrate. placement. Design recommendations Glide depth and morphology to provide appropriate flow velocities Provision of suitably sized spawning substrate. that reduce fine sediment deposition. Design recommendations Glide depth and morphology to provide appropriate flow velocities that Maximise flow heterogeneity through the creation of diverse bed Provision of suitably sized spawning substrate. reduce fine sediment deposition. topography. Glide depth and morphology to provide appropriate flow velocities Maximise flow heterogeneity through the creation of diverse bed that reduce fine sediment deposition. topography. Maximise flow heterogeneity through the creation of diverse bed topography. Bullhead (Cottus Positive Positive Positive gobio) Provision of vital habitat for bullhead spawning and adult and Provision of vital habitat for bullhead spawning and adult and YOY Provision of vital habitat for bullhead spawning and adult and YOY (young YOY (young of year) fish life stages. (young of year) fish life stages. of year) fish life stages. Improvement to local water quality through turbulent flow and Diversification of instream flow character. Diversification of instream flow character. resultant increase in DO concentration. Improvement to local water quality through turbulent flow and Provision of suitable habitat for macroinvertebrate prey items and Diversification of instream flow character. resultant DO concentration. macrophyte cover e.g. Ranunculus. Provision of suitable habitat for macroinvertebrate prey items and Provision of suitable habitat for macroinvertebrate prey items and Improved depth through bed raising. macrophyte cover e.g. Ranunculus. macrophyte cover e.g. Ranunculus. Improved depth through bed raising. Negative Negative Potential to cause damage to existing populations during installation of bed Potential to cause damage to existing populations during gravel Negative raising measures. placement. Potential to cause damage to existing populations during gravel placement. Design recommendations Design recommendations Habitat value can be further increased through addition of larger Habitat value can be further increased through addition of larger Design recommendations stone/boulder substrates within gravel glide. stone/boulder substrates within gravel glide. Habitat value can be further increased through addition of larger Maximise flow heterogeneity through the creation of diverse bed Maximise flow heterogeneity through the creation of diverse bed stone/boulder substrates within gravel glide. topography. topography. Maximise flow heterogeneity through the creation of diverse bed topography.

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Species / Gravel glides Gravel glides + transverse hurdles Bed raising (large scale) community

Desmoulin’s whorl n/a n/a Positive snail (Vertigo Potential to improve local water level regime through more frequent moulinsiana) inundation of marginal habitats.

Design recommendations Incorporate measures such as lowering embankments and berm creation.

3260 Water Positive Positive Positive courses of plain to Provision of suitable rooting habitat for Ranunculus community Provision of suitable rooting habitat for Ranunculus community Provision of suitable rooting habitat for Ranunculus community vegetation. montane levels vegetation. vegetation. Provision of favourable flow and depth conditions for development of with the Provision of favourable flow and depth conditions for Provision of favourable flow and depth conditions for development Ranunculus vegetation. Ranunculion development of Ranunculus vegetation. of Ranunculus vegetation. fluitantis and Negative Callitricho- Negative Negative Batrachion Design recommendations vegetation Design recommendations Design recommendations Provide varied glide depth and morphology to maximised flow diversity. Provide varied glide depth and morphology to maximised flow Provide varied glide depth and morphology to maximised flow Consideration given to translocation of existing plants to encourage diversity. diversity. establishment. Consideration given to translocation of existing plants to Consideration given to translocation of existing plants to encourage encourage establishment. establishment.

White-clawed Positive Positive Positive crayfish Provision of suitable habitat and foraging area for white-clawed Provision of suitable habitat and foraging area for white-clawed Provision of suitable habitat and foraging area for white-clawed crayfish. (Austropotamobius crayfish. crayfish. Improvement to local water quality through turbulent flow and resultant pallipes) Improvement to local water quality through turbulent flow and Improvement to local water quality through turbulent flow and increase in DO concentration. resultant increase in DO concentration. resultant increase in DO concentration. Negative Negative Negative Potential to cause damage to existing populations during gravel placement. Potential to cause damage to existing populations during gravel Potential to cause damage to existing populations during gravel placement. placement. Design recommendations Glide depth and morphology to provide appropriate flow velocities that Design recommendations Design recommendations reduce fine sediment deposition. Glide depth and morphology to provide appropriate flow velocities Glide depth and morphology to provide appropriate flow velocities Maximise flow heterogeneity through the creation of diverse bed that reduce fine sediment deposition. that reduce fine sediment deposition. topography. Maximise flow heterogeneity through the creation of diverse bed Maximise flow heterogeneity through the creation of diverse bed Habitat value can be further increased through addition of larger topography. topography. stone/boulder substrates within gravel glide. Habitat value can be further increased through addition of larger Habitat value can be further increased through addition of larger stone/boulder substrates within gravel glide. stone/boulder substrates within gravel glide.

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C.4 Potential impacts of other river restoration measures on the European features of the River Wensum SSSI/SAC

Other

Species / Fencing Tree planting on Tree felling Deflector (using LWD Lower spoil Channel re- Berm creation where Backwaters – Backwaters – new Channel realignment Changing Lower community embankment and filled in with brush embankments sectioning appropriate reconnections to primary and embankments mattress) IDB, field drains secondary channels n/a Positive Positive Positive Positive Positive Positive Positive Positive Positive Positive Positive Localised shading General Improvement of flow General improvement General improvement Berm creation will Increase in the Increase in the extent Promotion of more Potential to General improvement may inhibit improvement to conditions adjacent to to channel form and to channel form and increase flow velocities extent of habitat of available marginal natural flow character improve the extent to channel form and development of instream habitat deflector which will act process through process through (most effective during available for ammocoete habitat. and sediment regime of suitable process through algae, improving through to improve spawning increase in duration of increase in duration of low flow periods) and utilisation by Provision of refuge favouring habitat spawning and/or increase in duration spawning habitat encouragement of gravels through silt channel forming flows. channel forming flows. reduce local fine spawning adult or areas during high flow development for both larval habitat. of channel forming ) quality. natural narrowing removal. Increased connectivity sediment deposition larval ammocoete events. adult and larval life flows. process. Associated fine with floodplain Negative improving spawning life stages. stages. Negative Increased Design sediment deposition will features that provide Potential to cause habitat if gravels are Design Potential to reduce connectivity with recommendations Negative provide ammocoete shelter and refuge for damage to existing present. recommendations Negative habitat quality for floodplain features Incorporate Reduced shade habitat. lamprey. populations during Ensure sweetening Potential to cause ammocoete life that provide shelter additional measures may encourage implementation of Negative flow is maintained to damage to existing stages where and refuge for such as fencing to development of Negative Design measure. Potential to cause reduce risk of silting populations during primary channel lamprey. Lampetra planeri remove algae reducing Potential to cause recommendations damage to existing up of backwater implementation of provides extensive grazing/trampling spawning habitat damage to existing Incorporate with populations during features. measure. silt beds for larval pressure. quality at a local populations during additional measures implementation of development. Design scale. gravel placement. such as gravel measure. Potential to affect recommendations placement. existing population Incorporate with Design Design Design through changes additional measures

Brook lamprey ( recommendations recommendations recommendations in water such as gravel Adopt selective Incorporate with Incorporate additional availability. placement. felling to ensure additional measures measures such as some tree cover such as gravel gravel placement and remains of varied placement. deflectors. age structure.

Positive Positive Positive Positive Positive Positive Positive Positive Positive Positive Positive Positive Encourage Riparian tree General Improvement of flow Increased connectivity Return of natural Localised channel Improved Increase in the extent Promotion of more Potential to General improvement riparian tree development will improvement to conditions through with floodplain channel form and narrowing may promote connectivity to of available marginal natural flow character improve the extent to channel form and establishment to provide shade and instream habitat deflector installation features that provide function will promote increased flow additional habitats ammocoete habitat and sediment regime of available process through supply shade and shelter as well as through combined with marginal shelter and refuge for conditions that will velocities, improving suitable for especially where fine favouring habitat habitat. increase in duration shelter as well as valuable input of encouragement of facilitation of fine bullhead. favour species and physical habitat colonisation by sediment deposition is development for both of channel forming valuable input of woody debris and natural narrowing sediment deposition. General improvement potentially improve conditions for bullhead. bullhead. favoured. adult and larval life Negative flows. woody debris and leaf litter. process. to channel form and densities and standing Increase in the Provision of refuge stages. Potential to affect Increased leaf litter. Reduction in Negative process through crop. Negative extent of habitat areas during high flow existing population connectivity with Improved bank localised sediment Negative Potential to cause increase in duration of Potential to cause available for events. Negative through changes floodplain features stability and input through Localised removal damage to existing channel forming flows. Negative damage to existing utilisation by Potential to cause in water that provide shelter reduced sediment improved bank of shade and populations during Potential to cause populations during bullhead for shelter damage to existing availability. and refuge for input. stability. shelter plus gravel placement. damage to existing implementation of from high flow Design populations during bullhead. reduction in populations during measure. events and/or recommendations implementation of ) valuable supply of implementation of additional Ensure sweetening measure. Design Design woody debris and measure. Design spawning habitat flow is maintained to Design recommendations recommendations leaf litter. recommendations and nursery reduce risk of silting recommendations Incorporate Incorporate Reduced shade Design Incorporate additional grounds. up of backwater Incorporate with planting of native additional measures may encourage recommendations design measures such features. additional measures

Cottus gobio deciduous such as fencing to development of Incorporate additional as gravel placement such as gravel species that will remove algae reducing measures such as and deflectors. placement. provide seasonal grazing/trampling spawning habitat gravel placement. input of leaf litter. pressure. quality at a local

Bullhead ( Planting of native scale. deciduous species that will provide Design seasonal input of leaf recommendations litter. Adopt selective felling to ensure some tree cover remains of varied age structure.

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Species / Fencing Tree planting on Tree felling Deflector (using LWD Lower spoil Channel re- Berm creation where Backwaters – Backwaters – new Channel realignment Changing Lower community embankment and filled in with brush embankments sectioning appropriate reconnections to primary and embankments mattress) IDB, field drains secondary channels Positive Positive Positive Positive Positive Positive Positive Positive Positive Positive Positive Positive Exclusion of Reduced shading Potential for Improve connectivity Re-sectioning may Berm creation may Increase in the Backwater areas may Potential to improve Improvement of Lowering of grazing pressure Negative of wetland plant establishment of between river and favour growth of favour growth of extent of habitat improve the extent of marginal habitat water level embankments may from marginal Increased shading of communities and marginal wetland marginal habitats. If marginal plants and marginal plants and available for area available for quality. regimes in improve the extent of areas and wetland plant reduction in local vegetation on lateral silt suitable water level provided suitable provided suitable water colonisation by colonisation by adjacent floodplain area available for encouragement of communities water demand. berms. regimes are water level regimes level regimes are wetland plants. marginal plants and, Negative area through colonisation by ) marginal plant associated with snail maintained snail are maintained snail maintained snail Potential to provided suitable Potential to cause increase in ground marginal plants and, development. populations. populations may populations may populations may improve water water levels are damage to existing water levels. provided suitable Reduction in Local effects on Design benefit. benefit. benefit. levels adjacent to maintained, snail populations during water levels are poaching of water availability recommendations Improve dispersal of main river. populations may implementation of Negative maintained, snail marginal habitats. through tree uptake. Encourage species through Negative Negative benefit. measure. Potential to affect populations may vegetation improved connectivity Potential to cause Potential to cause existing population benefit. Negative Design establishment on in river corridor. damage to existing damage to existing Negative Design through changes May eventually recommendations silt berms through populations during populations during Potential to cause recommendations in water Negative Vertigo moulinsiana result in Ensure planting does transplantation of Negative implementation of implementation of damage to existing Promote suitable availability. development of not create a appropriate Potential to cause measure. measure. populations during water level regimes in Design marginal tree significant shading wetland plants. damage to existing implementation of marginal areas recommendations cover and hence impact on existing populations during Design Design measure. through appropriate Incorporate with loss of suitable suitable snail habitat. implementation of recommendations recommendations channel design. additional measures habitat. measure. Encourage marginal Encourage marginal Design such as gravel vegetation vegetation recommendations placement. Design establishment through establishment through Encourage marginal recommendations transplantation of transplantation of vegetation Encourage marginal appropriate wetland appropriate wetland establishment through

Desmoulin’s whorl snail ( vegetation plants in treated plants in treated areas. transplantation of establishment through areas. appropriate wetland transplantation of plants in treated appropriate wetland areas. plants in treated areas.

Positive Negative Positive Positive Positive Positive Positive n/a n/a Positive Positive Positive Improved bank Gradual increase in Reduction of local Improvement of flow General improvement General improvement General improvement to Promotion of natural Potential to General improvement stability may shading will, over shading will conditions favouring to channel form and to channel form and channel form and flow and sediment provide more to channel form and reduce localised time, favour more promote Ranunculus growth process through process. process. regime conducive to appropriate flow process through sediment input. shade tolerant Ranunculus downstream of flow increase in duration of Ranunculus conditions for increase in duration species. growth. Selective deflector. channel forming flows. Negative Negative communities. Ranunculus of channel forming Negative tree felling Potential to cause Potential to cause development. This flows. Development of Design encouraged over Negative Negative damage to existing damage to existing Negative potential is

Callitricho-Batrachion riparian recommendations widespread Potential to cause vegetation stands vegetation stands Potential to cause improved if Negative vegetation will Provide varied shade removal to provide damage to existing Design during implementation during implementation damage to existing secondary channel

and increase shading pattern through a mosaic of shade vegetation stands during recommendations of measure. of measure. communities during contains more Design increasing selective planting and light habitats. implementation of Incorporate with implementation of appropriate recommendations competition from locations. measure. additional measures Design Design measure. substrate e.g. Incorporate with more shade Negative such as gravel recommendations recommendations areas of gravel. additional measures tolerant species. Potential to Design placement. Incorporate with Incorporate with such as gravel increase the recommendations additional measures additional measures Negative placement. development of Incorporate with such as gravel such as gravel Potential to affect competitive algal additional measures placement. placement. existing stands of

Ranunculion fluitantis species e.g. such as gravel vgetation through epiphytes. placement. changes in water availability.

Design recommendations Incorporate with additional measures such as gravel placement.

vegetation vegetation 3260 Water courses of plain to montane levels with plain levels with courses of the montane to 3260 Water

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River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Species / Fencing Tree planting on Tree felling Deflector (using LWD Lower spoil Channel re- Berm creation where Backwaters – Backwaters – new Channel realignment Changing Lower community embankment and filled in with brush embankments sectioning appropriate reconnections to primary and embankments mattress) IDB, field drains secondary channels Positive Positive Positive Positive Positive Positive Positive Positive Positive Positive Positive Positive Encourage Riparian tree Reduction of local Improvement of flow General improvement Return of natural Localised channel Increase in Increase in available Promotion of more Potential to General improvement riparian tree development will shading will conditions adjacent to to channel form and channel form and narrowing may promote available habitat habitat and dispersal natural flow character improve the extent to channel form and establishment to provide shade and promote increased deflector which will act process through function will promote increased flow velocities and dispersal for for existing white- and sediment regime of available process through supply shade and shelter as well as instream to improve habitat increase in duration of conditions that will improving physical existing white- clawed crayfish favouring habitat habitat. increase in duration ) shelter as well as valuable input of productivity quality for white-clawed channel forming flows. favour this species. habitat conditions for clawed crayfish populations. development for of channel forming valuable input of woody debris and potentially crayfish. white-clawed crayfish. populations. Reduced vulnerability white-clawed crayfish. Negative flows. woody debris and leaf litter. increasing Negative Reduced to anthropogenic Potential to affect leaf litter. Reduction in availability of food Negative Design Potential to cause Negative vulnerability to disturbance. Negative existing population A. pallipes Improved bank localised sediment items. Potential to cause recommendations damage to existing Potential to cause anthropogenic Potential to cause through changes Design stability and input through damage to existing Incorporate with populations during damage to existing disturbance. damage to existing in water recommendations reduced sediment improved bank populations during additional measures implementation of populations during populations during availability. Incorporate with input. stability. gravel placement. such as gravel measure. implementation of Negative implementation of additional measures placement. measure. Removal of barrier measure. such as gravel Design Design previously placement. Design Design recommendations recommendations Design preventing recommendations recommendations Incorporate with Incorporate additional recommendations colonisation of Incorporate Planting of native additional measures measures such as Incorporate additional reaches by planting of native deciduous species such as gravel gravel placement. design measures such competitive and White-clawed crayfish ( deciduous that will provide placement. as gravel placement damaging species species that will seasonal input of leaf and deflectors. e.g. signal crayfish. provide seasonal litter. input of leaf litter.

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Appendix D – Terrestrial SSSI unit links to River Wensum SSSI units

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Appendix D – Links between terrestrial and riverine units of the River Wensum SSSI units

Terrestrial Riverine RWRS reach/reaches Details of Terrestrial SSSI unit Natural England comments on Action SSSI SSSI linkage between terrestrial and units units riverine SSSI units Name: Dunton Farm  No spoil banks. Conceptual design 5 (Full 47 29  Impacted through impoundment proposes: SSSI ID Location: TF889301 at Sculthorpe Mill, therefore 1023150) hydrological connectivity not  Channel re-sectioning. Area: 4.63ha appropriate.  Backwater creation.

 Channel form highly modified.  Work must take into Type: Fen, marsh and swamp - lowland  Feasibility study for river account the rich nature

restoration needs to consider the of the communities Management: Vegetation semi-natural and opportunities for reconnection of that this land parcel dominated by reedbed and scrub habitats. No the appropriate hydrological supports. grazing regime. Generally, the lack of grazing relationship between the river and regime is beneficial to the BAP habitats that this this unit of the SSSI. unit supports. However, scrub is encroaching on reedbed habitats. Name: Dunton Farm  No spoil banks. Conceptual design 6 (Full 47 29  Impacted through impoundment proposes: SSSI ID Location: TF888300 at Sculthorpe Mill, therefore 1023151) hydrological connectivity not  Channel re-sectioning. Area: 3.53ha appropriate.  Backwater creation.

 Channel form highly modified.  Work must take into Type: Fen, marsh and swamp - lowland  Feasibility study for river account the rich nature

restoration needs to consider the of the communities Management: Lack of grazing regime favours opportunities for reconnection of that this land parcel appropriate conditions for Desmoulin’s whorl the appropriate hydrological supports. snail. relationship between the river and this unit of the SSSI.

Name: Manor Farm Crisp  Significant spoil banks between Conceptual design 7 (Full 47 29 river and Unit 7. proposes: SSSI ID Location: TF892301  Impacted through impoundment 1023120) at Sculthorpe Mill, therefore  Channel re-sectioning. Area: 2.64 hydrological connectivity not  Backwater creation.

appropriate.  Work must take into Type: Neutral grassland – lowland  Channel form highly modified. account the rich nature

 Feasibility study for river of the communities Management: Vegetation semi-natural and restoration needs to consider the that this land parcel dominated by floodplain and grazing marsh opportunities for reconnection of habitats. Grazed by cattle, but no indications of the appropriate hydrological Unit 47 Tatterford Common to Fakenham Mill_Final.docx 188

River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Terrestrial Riverine RWRS reach/reaches Details of Terrestrial SSSI unit Natural England comments on Action SSSI SSSI linkage between terrestrial and units units riverine SSSI units inappropriate levels of poaching. relationship between the river and supports. this unit of the SSSI.

Name: Sculthorpe Moor  There are very significant spoil Conceptual design 8 (Full 47 28 banks between the river and Unit proposes: SSSI ID 8 and the river channel has been 1023115) Location: TF902300 moved from its original course.  Channel realignment.  The unit is hydrologically  Berm creation and re- Area: 13.16ha disconnected from the river, and sectioning. is drained through the network of  Gravel glide creation. Type: Broadleaved, mixed and yew woodland – internal drains and IDB drains.  Backchannel lowland Although the relationship reconnection. between the river and this unit is  Work must take into Management: Vegetation semi-natural and not what would be deemed account the rich nature dominated by floodplain habitats. Reedbed appropriate in relation to river of the communities vegetation - No grazing regime. Management function, there are other factors to that this land parcel compatible with special interest of the river. An consider in terms of the habitats supports. ambitious management regime has been and species that this unit instigated by the Hawk & Owl Trust, which has supports as a result of the very had dramatic benefits for a wide range of BAP nutrient poor groundwater that habitats including fen meadows, reed-bed, and feeds the site. beds of great fen sedge. Significant progress has been made with regard to scrub clearance, water level management and management of the sedgebeds and reedbeds. Name: Fakenham, Fakenham Town Council  This unit is not immediately Conceptual design 9 (Full 47 27 adjacent to the river. proposes: SSSI ID Location: TF913298  Impacted through impoundment 1023155) at Fakenham Mill and drainage  Lower spoil Area: 1.41ha related to IDB drain. embankments.

 Need to consider the  Berm creation. Type: Fen, marsh and swamp - lowland opportunities for reconnection of  Tree thinning /

the appropriate hydrological planting. Management: This unit supports a range of relationship between the river  Backwater creation. habitat, and is managed through an extensive Unit 47 and the floodplain and  Gravel glide creation. grazing regime. The grazing regime is at a very key to this will be consideration  Restoring flow to low intensity, and is therefore deemed to be as to whether the impoundment meander loop. compatible with the presence of Desmoulin’s at Fakenham Mill can be whorl snail. reduced.  Work must take into account the rich nature  Opportunities for reconnection of of the communities river and floodplain are limited by Unit 47 Tatterford Common to Fakenham Mill_Final.docx 189

River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Terrestrial Riverine RWRS reach/reaches Details of Terrestrial SSSI unit Natural England comments on Action SSSI SSSI linkage between terrestrial and units units riverine SSSI units the road infrastructure, by the that this land parcel close proximity of the outskirts of supports. Fakenham, and by the requirements of the IDB to maintain a drain which forms part of the flood risk management system for Fakenham.

Name: Fakenham R. C. Edmondson Ltd.  This unit is not immediately Conceptual design 10 (Full 47 27 adjacent to the river. proposes: SSSI ID Location: TF914296  Impacted through impoundment 1023156) at Fakenham Mill and drainage  Lower spoil Area: 1.06ha related to IDB drain. embankments.

 Need to consider the  Berm creation. Type: Fen, marsh and swamp - lowland opportunities for reconnection of  Tree thinning /

the appropriate hydrological planting. Management: This unit supports a range of relationship between the river  Backwater creation. habitat, and is managed through an extensive Unit 47 and the floodplain and  Restoring flow to grazing regime. The grazing regime is at a very key to this will be consideration meander loop. low intensity, and is therefore deemed to be as to whether the impoundment  Work must take into compatible with the presence of Desmoulin’s at Fakenham Mill can be account the rich nature whorl snail reduced. of the communities  Opportunities for reconnection of that this land parcel river and floodplain are limited by supports. the road infrastructure, by the close proximity of the outskirts of Fakenham, and by the requirements of the IDB to maintain a drain which forms part of the flood risk management system for Fakenham.

Name: Fakenham – Town Council land  This unit is not immediately Conceptual design 11 (Full 47 27 adjacent to the river. proposes: SSSI ID Location: TF915296  Impacted through impoundment 1018794) at Fakenham Mill and drainage  Lower spoil Area: 2.69ha related to IDB drain. embankments.

 Need to consider the  Berm creation. Type: Fen, marsh and swamp - lowland opportunities for reconnection of  Tree thinning / the appropriate hydrological Unit 47 Tatterford Common to Fakenham Mill_Final.docx 190

River Wensum Restoration Strategy Implementation SSSI Unit 47: Feasibility and Environmental Scoping Report

Terrestrial Riverine RWRS reach/reaches Details of Terrestrial SSSI unit Natural England comments on Action SSSI SSSI linkage between terrestrial and units units riverine SSSI units Management: This unit supports a range of relationship between the river planting. habitat, and is managed through an extensive Unit 47 and the floodplain and  Backwater creation. grazing regime. The grazing regime is at a very key to this will be consideration  Restoring flow to low intensity, and is therefore deemed to be as to whether the impoundment meander loop. compatible with the presence of Desmoulin’s at Fakenham Mill can be  Work must take into whorl snail reduced. account the rich nature  Opportunities for reconnection of of the communities river and floodplain are limited by that this land parcel the road infrastructure, by the supports. close proximity of the outskirts of Fakenham, and by the requirements of the IDB to maintain a drain which forms part of the flood risk management system for Fakenham.

Notes – 1. ‘Terrestrial SSSI units’ refers to non-riverine units of the River Wensum SSSI (e.g. SSSI ID 1023117)). 2. ‘Riverine SSSI units’ refers to those units of the River Wensum SSSI that comprise sections of river channel (e.g. Unit 47). 3. ‘RWRS reaches’ refers to reaches of river channel as defined in the River Wensum Restoration Strategy. 4. ‘Details of terrestrial SSSI unit’ are taken from Nature on the Map: http://www.natureonthemap.org.uk/ 5. ‘Natural England comments on linkage between terrestrial and riverine SSSI units’ are those from an emerging condition assessment of terrestrial SSSI units undertaken by Natural England. 6. ‘Action’ refers to those proposed options/measures in the conceptual design undertaken by Atkins. Changes in river / floodplain hydrology will be considered at detailed design stage as modelling will be required to determine the extent of the relationship. It is inappropriate at this stage due to the potential complexity of this relationship. Reasons stated for “unfavourable condition” of individual SSSI units will be included in the drivers for the design.

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