A Field Guide to British Rivers E-Book

George Heritage

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 379

Veröffentlichungsjahr: 2021

Beschreibung

Temperate rivers are influenced by many factors including geology, climate, soils, sediment type, flow, as well as human activity. The complex interactions of the non-anthropogenic controlling factors have led to a wonderful diversity of river type throughout the British Isles. Sadly, almost all rivers in the UK have suffered significant and long-lasting modification by unsympathetic management, that has all but destroyed this variety, creating watercourses that are simplified conduits for water and sediment, designed primarily to drain the land and reduce flood risk. This volume aims to help reverse this, illustrating using over 200 images and descriptions, this variety of rivers in Britain, highlighting the many forms that temperate river systems take and providing an accessible summary of the underlying river science knowledge base.  

A Field Guide to British Rivers covers the full range of upland and lowland channel types and describes the full variety of substrate conditions from bedrock through boulder, cobble and gravel, to silt dominated systems. The authors describe examples gathered from their extensive research and practical experience working with rivers throughout mainland Britain and set those examples in their wider landscape context to exemplify the natural functioning of temperate river types.  This book offers a practical and contextualised guide to contribute to efforts towards the sympathetic and sustainable restoration and re-naturalisation of degraded channels in the UK. Offering a unique viewpoint of both the underpinning science and the practicalities of river management, A Field Guide to British Rivers is an essential a stand-alone guide for anyone involved in river restoration and management as well as for those simply interested in rivers in general. 

Written as a field guide to demonstrate practical examples of river types, and to highlight the pressures they experience and their often-parlous condition, this book is intended to better inform both river management approaches and the policy necessary to achieve this. Fundamentally, the authors seek to demonstrate how the hydrological, geomorphological, and ecological functions of rivers and their catchments are inexorably intertwined, and together how they generate and maintain rivers as dynamic entities. 

Leseprobe

Table of Contents

Cover

Title Page

Copyright Page

Dedication Page

Foreword

1 British Rivers

1.1 Introduction

1.2 The Importance of River and Floodplains

1.3 River and Floodplain Degradation

1.4 River and Floodplain Recovery

1.5 Purpose of This Book

2 River Types: A Brief Overview

2.1 Introduction

2.2 Classification

2.3 Functional Classifications

2.4 River Classification Framework Used in This Book

3 River Types: Observations and Theory

3.1 Diffuse Upland Channels

3.2 Bedrock Channels: Background Research

3.3 Bedrock Influenced Channels: Step‐Pool Channel

3.4 Pool‐Rapid Channels

3.5 Wandering Channels

3.6 Coarse‐Sediment Anabrancing Channels

3.7 Fine‐Sediment Anastomosed Channels

3.8 Active Single‐Thread Channels

3.9 Passive Single‐Thread (Varied Sinuosity)

4 “Reading” Rivers

4.1 Morphologic Unit‐Based Process Indicators

5 Towards Sensitive And Appropriate Management

5.1 Historic and Current River and Floodplain Alteration

5.2 Extent of Channel Change

5.3 Towards the Future

References

Place and River Index

Subject Index

End User License Agreement

List of Tables

Chapter 2

Table 2.1 River types identified by Montgomery and Buffington (1997) along w...

Table 2.2 Additional river types to those listed in Table 2.1, with channel ...

Table 2.3 Functional channel types defined by SEPA (2012).

Table 2.4 General character of functional channel types as defined by SEPA (...

Table 2.5 Basic character and processes operating in the channel types used ...

Table 2.6 Typical in‐channel morphologic assemblages by river type.

Table 2.7 Typical valley bottom morphologic assemblages by river type.

Chapter 4

Table 4.1 Key temperate river process indicators.

Table 4.2 Feature‐process indicators occurring over different timescales on...

Chapter 5

Table 5.1 Occurrence of habitat types on 555 English rivers.

List of Illustrations

Chapter 1

Figure 1.1 Water Framework Directive status summary for UK Rivers (2008–2015...

Figure 1.2 Cause of hydromorphic degradation in the UK.

Figure 1.3 Typical heavily modified lowland system with artificial flood pro...

Figure 1.4 Typical heavily modified upland system, straightened, walled, and...

Figure 1.5 Semi‐natural multi‐channel network on the River Narr.

Figure 1.6 Laterally migrating active channel on the River Mallart, Syre, no...

Figure 1.7 Active reach of the River Glen at Kirknewton, Northumberland, sho...

Figure 1.8 Wandering reach of the River South Esk, Scotland, showing sedimen...

Chapter 2

Figure 2.1 River types on the sediment supply continuum.

Figure 2.2 Channel type change with river gradient, sedimentology, and disch...

Figure 2.3 The River Styles typology

Figure 2.4 The Extended River typology

Figure 2.5 Temperate river typology used in this volume.

Chapter 3

Figure 3.1 Continuum of potential change routes and feedback controls for ri...

Figure 3.2 Stream head, Thinhope Burn, South Tyne, UK.

Figure 3.3 Subsurface hydrology in the headwaters of Thinhope Burn catchment...

Figure 3.4 Relationships between catchment areas and local channel head slop...

Figure 3.5 Moorland seepage zone on the Lagrae Burn, a tributary of the Rive...

Figure 3.6 Bedrock step on the upper River Wharfe, Buckden, North Yorkshire....

Figure 3.7 Boulder step reach of the Church Beck, above Coniston, Lake Distr...

Figure 3.8 Bedrock pool reach on the Brockle Beck, which flows into Derwentw...

Figure 3.9 Overland flow channel, Stonethwaite Beck, Borrowdale, Lake Distri...

Figure 3.10 The bedrock channel system

Figure 3.11 Boxplots showing the (a) channel slope (b) total stream power ch...

Figure 3.12 Bedrock gorge section on the Lagrae Burn, a tributary of the Riv...

Figure 3.13 Bedrock outcrop and new sediment delivered to the channel on the...

Figure 3.14 Bedrock‐controlled cascade on the Lagrae Burn Scotland.

Figure 3.15 Bedrock‐controlled rapid on the upper reaches of the River Calde...

Figure 3.16 Bedrock‐influenced pool on Church Beck, Coniston, Lake District....

Figure 3.17 High‐gradient stream long‐profile morphology (a) rapid channel m...

Figure 3.18 Simplified representation of flow over step‐pool morphology

Figure 3.19 Boulder‐dominated berm feature, right‐hand bank looking downstre...

Figure 3.20 Boulder splay/alluvial fan deposit, Millkeld Sike, Helton, Lake ...

Figure 3.21 Narrowed valley and shifted channel linked to valley side slumpi...

Figure 3.22 Waterfall on the Black Devon, Fife, Scotland.

Figure 3.23 Small plunge pool and associated bar, Church Beck, Coniston, Lak...

Figure 3.24 Bedrock step, Glen Cloy, Carradale, Kintyre, Scotland.

Figure 3.25 Boulder step reach, Church Beck, Lake District.

Figure 3.26 Bedrock pool, Brockle Beck, Lake District.

Figure 3.27 Lag boulders in the channel on the Stonethwaite Beck, Lake Distr...

Figure 3.28 Boulder rapid formed from material delivered from a steep headwa...

Figure 3.29 Cobble/boulder rapid formed in situ from material delivered from...

Figure 3.30 Coarse lateral bar stored on bedrock, Brockle Beck, Lake Distric...

Figure 3.31 Lee bar deposit downstream of a bedrock outcrop on the South Esk...

Figure 3.32 Sand/silt drapes along the channel margin of the South Esk, Scot...

Figure 3.33 Slope character for different channel types (a) Bed slope with 9...

Figure 3.34 Characterisation of step‐pool morphology

Figure 3.35 Boulder and cobble pool‐rapid on the upper River Garnock, Kilbir...

Figure 3.36 Boulder cascade on the upper River Caldew, Mosedale, Lake Distri...

Figure 3.37 Hydraulically controlled cobble/boulder rapids, River Glen, Kirk...

Figure 3.38 Outcrop‐induced rapid on the Upper Garnock, Kilbirnie, Ayrshire,...

Figure 3.39 Erosion‐induced bank collapse leading to an instream rapid, Rive...

Figure 3.40 Plane‐bed‐rapid section on the South Esk, Brechin, Scotland.

Figure 3.41 Coarse sediment pool upstream of a rapid on Swindale Beck, Lake ...

Figure 3.42 Tributary fans along the valley margin of the upper River Caldew...

Figure 3.43 Palaeo‐channels preserved across the now‐inactive wandering terr...

Figure 3.44 Formerly active zone of the wandering gravel‐bed River Coquet, R...

Figure 3.45 Active zone on the wandering gravel‐bed River Coquet, Rothbury, ...

Figure 3.46 Local knickpoint erosion caused by channel avulsion, River Glen,...

Figure 3.47 Stabilised inset berm on the wandering reach of the River Malart...

Figure 3.48 Well‐preserved palaeo‐channel on the River Glen, Kirknewton, Nor...

Figure 3.49 Recent cutoff channel on the River Dee, Ballater, Scotland.

Figure 3.50 Chute cutoff channel on the Carradale Water, Kintyre, Scotland....

Figure 3.51 Multiple gravel splay deposits on the River Dee, Ballater, Scotl...

Figure 3.52 Bar and islands, Wooler Water, Wooler, Northumberland.

Figure 3.53 Point bar composed of fine sediments, River Dee, Scotland.

Figure 3.54 Coherent sub‐bar depositional units. River Dee, Scotland.

Figure 3.55 Chute channels running across a coarse sediment bar. River South...

Figure 3.56 Chute channels re‐working a sediment bar on the River Coquet, Sh...

Figure 3.57 Long lateral bar deposit on a wandering reach of the River Dee, ...

Figure 3.58 Stalling mid‐channel bar. River Dee, Ballater, Scotland.

Figure 3.59 Mid‐channel bar formed from a dissected point bar. River Dee, Ba...

Figure 3.60 Transverse bar feature on the River Naver, Sutherland, Scottish ...

Figure 3.61 Transverse bar feature on the River Derwent, Workington, Cumbria...

Figure 3.62 Multiple riffle units on a wandering section of the River Nith, ...

Figure 3.63 Riffle unit on the Carradale Water, Kintyre, Scotland.

Figure 3.64 Multiple rapid units dissecting coarse sediment bars on the wand...

Figure 3.65 Cobble rapid on the River South Esk, Brechin, Scotland.

Figure 3.66 Isolated large wood with associated sediment deposition. River D...

Figure 3.67 Large wood integrated into the geomorphology of the Carradale Wa...

Figure 3.68 Large wood jam on the leading edge of a bar/island on the Wooler...

Figure 3.69 Cantilever failure along a river cliff on the River Ehen, Egremo...

Figure 3.70 Rotational bank failure along the River Ribble, Long Preston, Yo...

Figure 3.71 Older inactive floodplain/terrace zone outside of the current an...

Figure 3.72 Active anabranched floodplain on the Carradale Water, Kintyre, S...

Figure 3.73 Typical wooded secondary channel on the River Naver, Sutherland,...

Figure 3.74 Typical sub‐channel on an anastomosed reach of the Carradale Wat...

Figure 3.75 Vegetation‐induced bed scour on the Carradale Water, Kintyre, Sc...

Figure 3.76 Wooded island/bar on the College Burn, near Kirknewton, Northumb...

Figure 3.77 Isolated open water on the River Wear. Barnard Castle, County Du...

Figure 3.78 Pool section, Carradale Water, Kintyre, Scotland.

Figure 3.79 Well‐developed pool on the Carradale Water, Kintyre, Scotland.

Figure 3.80 Riffle section, River Ure, Ripon, Yorkshire.

Figure 3.81 Transverse bar feature on the Carradale Water, Kintyre, Scotland...

Figure 3.82 Point bar feature on the Carradale Water, Kintyre, Scotland.

Figure 3.83 Vegetation‐induced stalled bar/riffle feature on the Carradale W...

Figure 3.84 Terrace feature on a ponded anabranching reach of the River Wear...

Figure 3.85 Inactive floodplain on the River Freshney, Grimsby, Lincolnshire...

Figure 3.86 Active floodplain on Old Wark Dam, Salford, Manchester.

Figure 3.87 Secondary channel on the Latchmore Brook, New Forest, Hampshire....

Figure 3.88 Isolated pool on the River Nar, Narborough, Norfolk.

Figure 3.89 Wooded stable bar features on an anastomosed reach of the River ...

Figure 3.90 Wooded anastomosed reach of the River Nar, Narborough, Norfolk....

Figure 3.91 Main channel pool feature on the River Beane, Watton at Stone, H...

Figure 3.92 Fine sediment berm feature on the River Lark, Bury St Edmunds, C...

Figure 3.93 Fine sediment bar feature at the entrance zone of Tittesworth Re...

Figure 3.94 Woody debris feature on the River Beane, Watton at Stone, Hertfo...

Figure 3.95 Conceptual representations of different pool‐riffle formation me...

Figure 3.96 Conceptual representations of pool‐riffle maintenance mechanisms...

Figure 3.97 Terrace feature on the River Malart, Syre, Sutherland, Scottish ...

Figure 3.98 Multiple cut‐off channels preserved along an active pool‐riffle‐...

Figure 3.99 Avulsion‐driven cutoff feature on the River Coquet, Holystone, N...

Figure 3.100 Chute cutoff feature on the River Malart, Syre, Sutherland, Sco...

Figure 3.101 Low‐level berm on the River Glen, Kirknewton, Northumberland.

Figure 3.102 Gravel splay on Goldrill Beck, Patterdale, Lake District.

Figure 3.103 Pool‐riffle sequence on the River Winterbourne, Wiltshire, UK....

Figure 3.104 Long pool on a straight reach of the River Glen, Kirknewton, No...

Figure 3.105 Riffle unit on the River Naver, Sutherland, Scottish Highlands....

Figure 3.106 Pool features on the River Ehen, Egremont, Cumbria.

Figure 3.107 Example of an apical pool on the River Exe, above Exeter, Devon...

Figure 3.108 Point bar features on the moderately active River South Esk, Br...

Figure 3.109 Composite and uniform river banks. River Malart, Syre, Sutherla...

Figure 3.110 Coarse lateral bar and associated chute channel on the River De...

Figure 3.111 Lateral bar on the River Till, near Wooler, Northumberland, ill...

Figure 3.112 Transverse bar on the River Croal, Manchester.

Figure 3.113 Recent chute channel cutoff on the River Malart, Sutherland, Sc...

Figure 3.114 Plane‐bed section of the River Eamont, Penrith, Cumbria.

Figure 3.115 Plane‐bed‐riffle on the River South Esk, Brechin, Scotland.

Figure 3.116 Anastomosing stable‐bed and non‐stable bed aggrading banks evol...

Figure 3.117 Historic river use in the United Kingdom

Figure 3.118 Terraces on the passive single thread River Eye, Melton Mowbray...

Figure 3.119 Inactive floodplain of the River Wensum, Norwich, Norfolk.

Figure 3.120 Passive single thread channel floodplain features preserved on ...

Figure 3.121 Pool feature on the River Nar, Narborough, Norfolk.

Figure 3.122 Flow constriction and concentration creating a restricted riffl...

Figure 3.123 Relict riffle surface across an exposed chalk bed in the River ...

Figure 3.124 Vegetated mid‐channel bar unit on the River Witham, upstream of...

Figure 3.125 Sandy subdued lateral bar on Stevenage Brook, Stevenage, Hertfo...

Figure 3.126 Point bar unit on the River Mersey, Pointon, Lancashire.

Figure 3.127 Silty berm unit on the River Nar, upstream of Narborough, Norfo...

Figure 3.128 Dissected consolidated berm sediments on Worsley Brook, Manches...

Figure 3.129 Floating vegetation extending into the channel on the River Bla...

Figure 3.130 Vegetated inset berm on the River Lark, upstream of Bury St Edm...

Figure 3.131 Channel diversity‐induced by Willows on the River Eye at Melton...

Figure 3.132 Mixed live and dead wood‐dominated feature on the River Nar, up...

Figure 3.133 Lee bar associated with upstream in‐channel woody elements on t...

Chapter 4

Figure 4.1 Vertical exposed sediment and failed blocks, suggesting active ba...

Figure 4.2 Surface cracks along the bank margin suggesting incipient rotatio...

Figure 4.3 Cantilever failure on the composite banks of the River Dee, near ...

Figure 4.4 Multiple rotational failures along the banks of the River Mersey,...

Figure 4.5 Isolated rotational failure in cohesive bank material on the Rive...

Figure 4.6 Stable slumped blocks with healthy ungrazed vegetation growth on ...

Figure 4.7 Continuous long‐reach erosion and inner bank deposition suggestin...

Figure 4.8 Localised bank erosion linked to tree‐fall on the Carradale Water...

Figure 4.9 Localised erosion behind a flow deflectors (triangular croy struc...

Figure 4.10 Dramatic local erosion following revetment failure on the River ...

Figure 4.11 Fluvial erosion to the toe of a high fluvio‐glacial terrace on t...

Figure 4.12 New and older palaeo‐features across the floodplain of the Moffa...

Figure 4.13 Infilled palaeo‐channels on the Floodplain of the Welland and Gw...

Figure 4.14 Sequence of upstream channel development on the River Glen, Kirk...

Figure 4.15 Semi‐vegetated slumped banks on the River Mersey.

Figure 4.16 Recent bank erosion compromising a newly erected fence line on t...

Figure 4.17 Progressive tree loss along the right bank looking downstream. R...

Figure 4.18 Deep historically straightened narrow channel on the Holm Burn, ...

Figure 4.19 Channel incision moderated by bed armouring on the River Caldew,...

Figure 4.20 Exposed berm surface representing the former bed behind a lowere...

Figure 4.21 Exposed former bed gravels underlying finer floodplain deposits ...

Figure 4.22 Inset well‐connected vegetated lateral berm on the River Glen, K...

Figure 4.23 Inset incipient floodplain on the River Malart, Syre, Sutherland...

Figure 4.24 Eroded floodplain and juxtaposed gravel bar on the River Glen, K...

Figure 4.25 Bed armouring on the River Caldew, Hesketh Newmarket, Cumbria.

Figure 4.26 Wide coarse sediment margins inside vertical erosive banks on th...

Figure 4.27 Multiple bank failures along the River Ribble, Long Preston, Yor...

Figure 4.28 Isolated rotational failure on a drainage ditch on Swindale Beck...

Figure 4.29 Angled bankside trees in the Holm Burn, Inverness, Scotland, ind...

Figure 4.30 Upstream horseshoe scour around a bridge pier on the River South...

Figure 4.31 Historic repairs to the abutment of Brechin Bridge on the River ...

Figure 4.32 Late Holocene terraces, Thinhope Burn, Cumbria.

Figure 4.33 Rapid incision of up to 4 m following straightening on the Holm ...

Figure 4.34 Vegetated berms on the River Eye, Melton Mowbray, Leicestershire...

Figure 4.35 Vertical accretion associated with marginal vegetative growth on...

Figure 4.36 Lee bar deposit downstream of a Bridge on the River Till, near W...

Figure 4.37 Vegetated aggrading bar upstream of the A50 Bridge over the Rive...

Figure 4.38 Heavily sedimented drainage channel flowing into Worsley Brook, ...

Figure 4.39 Sedimented reach of the River Trent, Staffordshire University ca...

Figure 4.40 Stalled gravel lobes on the River Kent, Kendal, Lake District.

Figure 4.41 Stalled, stacked gravel lobes on the College Burn, near Kirknewt...

Figure 4.42 Gravel splay deposits left after a flood on the Goldrill Beck, P...

Figure 4.43 Loose gravel plane‐bed channel, Goldrill Beck, Patterdale, Lake ...

Figure 4.44 Coarse armoured plane‐bed on the River Glen, Kirknewton, Northum...

Figure 4.45 Infilled weir on the River Croal, Bury, Lancashire.

Figure 4.46 Buried historic weir on the River Ehen, Egremont, Cumbria.

Figure 4.47 Deposition through a peripheral bridge opening on the River Exe ...

Figure 4.48 Recently transported gravel on Swindale Beck, Swindale, Lake Dis...

Figure 4.49 Fresh gravel lobes on Swindale Beck, Swindale, Lake District.

Figure 4.50 Fine sediment ribbon over gravel on the River Black Devon.

Figure 4.51 Particle cluster on the River South Esk. Flow direction from top...

Figure 4.52 Silt drape on the lower banks of Swindale Beck.

Figure 4.53 Sand lobe features in the Black Devon, Cleish Hills, Fife, Scotl...

Figure 4.54 Ripple features in the Black Devon, Cleish Hills, Fife, Scotland...

Figure 4.55 Fine sediment bed choking on Swindale Beck, Swindale, Lake Distr...

Figure 4.56 Uniform featureless reach of the River Rede, downstream of Otter...

Figure 4.57 Inset reach of the River Rother, Rotherham, Yorkshire.

Figure 4.58 Inset reach of the River Rede downstream of Otterburn, Northumbe...

Figure 4.59 Strongly armoured bed on the River Caldew, Hesketh Newmarket, Cu...

Figure 4.60 Over‐loose riffle gravel on the River Lark upstream of Bury St E...

Figure 4.61 Loose plane‐bed reach of the River South Esk, Brechin, Scotland....

Figure 4.62 Excessive fine sediment on the bed of the River Granta, Linton, ...

Figure 4.63 Stalling gravel bars and lobes on the River Kent, Kendal, Lake D...

Figure 4.64 Stalled gravel in the vicinity of an avulsion site on the River ...

Figure 4.65 Gross deposition on the Culloden Burn, Smithdon, Inverness, Scot...

Chapter 5

Figure 5.1 Controls on river channel form and function, where thicker lines ...

Figure 5.2 Timeline of river and catchment alteration in the United Kingdom ...

Figure 5.3 Historic change in UK river systems (a) Middle Ages – semi‐natura...

Figure 5.4 Spatial extent of river channel and floodplain change in England,...

Figure 5.5 Key developments in stream science over the period 1960–2020h...

Guide

Cover Page

Title Page

Copyright Page

Dedication Page

Foreword

Table of Contents

Begin Reading

References

Place and River Index

Subject Index

Wiley End User License Agreement

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A Field Guide to British Rivers

George Heritage

Salford University, Salford, UK

Andy Large

University of Newcastle, Newcastle upon Tyne, UK

David Milan

University of Hull, Hull, UK

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Library of Congress Cataloging‐in‐Publication Data

[ISBN 9781118487983]

Cover image:Cover design by

In memory of Martin Charlton (1957–2021)

An unassuming academic with a brilliant mind, indubitable character and unbounded enthusiasm for his work and students. Martin will be missed by all who knew him. His influence will live on well beyond his short life.

Foreword

Temperate rivers are influenced by many factors including geology, climate, soils, sediment type, flow and human activity. The complex interactions of the non‐anthropogenic controlling factors have led to a wonderful variety of river form in the British Isles. Sadly, however, almost all temperate rivers in the United Kingdom have suffered significant and long‐lasting modification and management that has all but destroyed this variety, instead creating simplified conduits for water and sediment designed primarily to drain the land and reduce flood risk. This book is intended to illustrate this variety, highlighting the many forms that temperate river systems take in the United Kingdom. In this volume, we cover upland and lowland channel types and include the full range of substrate conditions from bedrock through boulder, cobble and gravel through to silt‐dominated systems. In doing this, we describe examples gathered from over 30 years each of research and practical experience working with rivers and set these in the context of the current scientific knowledge to illustrate the natural functioning of temperate river types. We hope this will act as a practical, context‐sensitive and more sustainable template for the restoration and re‐naturalisation of degraded channels in the United Kingdom and as a working set of guidelines for those interested in understanding more about the rich variety of temperate river types. In doing this, we know other examples exist (e.g. the practical guides from the UK River Restoration Centre), and so we intend this volume with its balance between science and practicalities of river management to compliment these other approaches but essentially to act as a stand‐alone guide.

It is interesting to reflect on the reasons behind the present degraded state of temperate rivers and the common acceptance that this current state is “how a river should be.” Significant, almost wholesale, channel and floodplain modification occurred throughout the agricultural and industrial revolution as valley bottomlands were exploited for food production and industrialists sought to utilise the power of rivers for energy for manufacturing activities. River channels were moved, straightened, embanked, and deepened, and the new channels had their banks protected with wood and stone. While large extents of natural wooded vegetation was removed as part of this activity, trees (but, more often than not, monoculture) were planted along bank margins to prevent them moving from their designated route. Floodplains and later uplands were drained to improve land for crops and grazing and urban rivers were completely channelised to prevent flooding. Generations have now grown up with these modified rivers, and as a result, we have now accepted that they are somehow “natural.” Our own limited experience of rivers has led to the widespread belief that rivers are liquid ribbons in the landscape; static systems, immovable in the landscape and not part of the surrounding floodplain fields and meadows. We talk of rivers “bursting their banks” – a negative term implying that overspilling to occupy the floodplain temporarily is somehow unnatural. Increasingly, as management of temperate rivers reduces on the part of national agencies, requests are made to “fix” rivers by “repairing” banks, dredging sediment, and removing wood and other vegetation to recreate the “neat” channels people remember from days gone by. Such perceptions are not aided by the current teaching of river science in schools. Geography and environmental lessons in schools perpetuate outdated concepts; for example, textbooks concentrate on meandering systems and pool‐riffle sequences and decades old river typologies that, despite rivers being continua, divide catchments into upper, mid‐reach and lowland meandering sections – ignoring the irony that the latter are rarely permitted to be mobile nowadays.

All these modifications have not just altered the physical form of temperate rivers and valley bottoms, they have also fundamentally impacted on the flow regime and the way in which river systems erode, transport and store sediment. As such, we are left with systems that are a neutered shadow of their former selves, where both natural processes and natural form are severely impacted resulting in a highly degraded river channel and valley bottom. The simple single‐thread channel, often featureless and constrained, dominates our riverine landscapes with many other river types now all but extinct. Many rivers also now experience more extreme flows across the year, with winter flood extremes testing flood defences to their limits and spring and summer low flows that border on drought conditions. Whilst both extremes may have their origins in climate change, there is no doubt that they have been exacerbated by inappropriate upland drainage management impacting on the flow paths and speed of water once it has hit the ground.

Such a situation should not be allowed to continue and fortunately several factors are presently operating that provide encouragement that more natural river and floodplain systems can make a resurgence. The first is the current reluctance amongst statutory bodies to continue with the intensive management of watercourses due to their routine maintenance budgets being significantly reduced from those of a decade or two ago. This is giving many rivers a chance to begin to erode and deposit sediment once again; however, channel response in often highly localised and more extreme than would occur naturally as failing protection creates “hotspots of change.” Alongside this, there is an increasing recognition that impacted flood regimes require addressing at source rather than just at flooding hotspots, and Natural Flood Management approaches to slow flood flows and store flood water are gaining traction in terms of catchment‐oriented efforts to restore river and floodplain connectivity and channel dynamism. More recently, it has been recognised that degraded sediment transport regimes are also influencing the potential for flooding with heightened levels of gravels accumulating in urban areas because of disconnected storage in the catchment and altered sediment transport efficiencies in upstream rivers. Natural Sediment Management where sediment storage zones are reconnected and channel form naturalised to a more storage friendly configuration can help reduce flood sediment inputs to vulnerable areas whilst restoring natural form and processes to the fluvial system upstream. Finally, the trend amongst owners of large estates to re‐wild the landscape and reintroduce extinct species is also improving larger and larger areas, often with valley bottom land being encouraged to naturalise through light touch interventions that act as the precursor for wider river‐driven landscape change. The recent efforts to reintroduce ecosystem engineers such as beaver also points to greater willingness in UK river managers to turn back the clock and allow greater space for nature.

The natural environment is now rising in value with an increasing recognition of the role that natural system dynamics can play in climate change, biodiversity, as well as amenity, and there appears to be a growing political will in the United Kingdom to instigate change, with new government stewardship schemes likely to place a very strong emphasis on environmental functionality, helping push the river restoration agenda forward. In all cases, this can only be achieved successfully with the appropriate knowledge. During the time we have been writing this book, Britain has left the European Union, and so it remains to be seen what trajectory environmental protection will take post departure, but initial statements from government indicate a willingness to legislate for more protection, not less. What is key is that any range of protection methods should ensure a place for enhanced dynamism, not less.

Future sustainable management of our rivers and floodplains therefore requires a fuller understanding of river form and function to ensure that opportunities are fully exploited, and our perception of rivers is changed towards more naturally functioning dynamic systems. We have written this book deliberately as a field guide to maximise the practical examples of river types and to highlight the pressures they experience and their often parlous condition. This book is intended to better inform both river management approaches and policy necessary to achieve this. It will hopefully stimulate a desire to bring back the diversity and dynamism associated with naturally functioning temperate fluvial systems in the United Kingdom. The ethos of the book is to inspire the river scientists in us all, by providing a holistic picture of the variety of temperate river forms in Britain and linking this explicitly to functional controls within the catchment. Fundamentally, we seek to demonstrate and evidence how the hydrological, geomorphological, and ecological functions of rivers integrate to generate and maintain the dynamic whole. If those who have read this book find themselves questioning what they see each time they encounter a river and its floodplain, this volume will have served its purpose.

George Heritage

Andy Large

David Milan

July 2021