Geomorphology and River Management

Applications of the River Styles Framework

Gary J. Brierley and Kirstie A. Fryirs

GEOMORPHOLOGY AND RIVER MANAGEMENT To our families

“Every tool carries with it the spirit by which it has been created.” Werner Karl Heisenberg Geomorphology and River Management

Applications of the River Styles Framework

Gary J. Brierley and Kirstie A. Fryirs ©ȱ2005ȱbyȱBlackwellȱPublishingȱ ȱ BLACKWELLȱPUBLISHINGȱ 350ȱMainȱStreet,ȱMalden,ȱMAȱ02148Ȭ5020,ȱUSAȱ 9600ȱGarsingtonȱRoad,ȱOxfordȱOX4ȱ2DQ,ȱUKȱȱ 550ȱSwanstonȱStreet,ȱCarlton,ȱVictoriaȱ3053,ȱAustraliaȱ ȱ TheȱrightȱofȱGaryȱJ.ȱBrierleyȱandȱKirstieȱA.ȱFryirsȱtoȱbeȱidentifiedȱasȱtheȱAuthorsȱofȱthisȱWorkȱhasȱbeenȱassertedȱinȱ accordanceȱwithȱtheȱUKȱCopyright,ȱDesigns,ȱandȱPatentsȱActȱ1988.ȱ ȱ Allȱrightsȱreserved.ȱNoȱpartȱofȱthisȱpublicationȱmayȱbeȱreproduced,ȱstoredȱinȱaȱretrievalȱsystem,ȱorȱtransmitted,ȱinȱanyȱ formȱorȱbyȱanyȱmeans,ȱelectronic,ȱmechanical,ȱphotocopying,ȱrecordingȱorȱotherwise,ȱexceptȱasȱpermittedȱbyȱtheȱUKȱ Copyright,ȱDesigns,ȱandȱPatentsȱActȱ1988,ȱwithoutȱtheȱpriorȱpermissionȱofȱtheȱpublisher.ȱ ȱ Firstȱpublishedȱ2005ȱbyȱBlackwellȱScienceȱLtdȱ ȱ 2ȱȱ 2006ȱ ȱ LibraryȱofȱCongressȱCatalogingȬinȬPublicationȱDataȱ ȱ Brierley,ȱGaryȱJ.ȱ Geomorphologyȱandȱriverȱmanagementȱ:ȱapplicationsȱofȱtheȱriverȱstylesȱframeworkȱ/ȱGaryȱJ.ȱBrierleyȱandȱ KirstieȱA.ȱFryirs.ȱ p.ȱcm.ȱ Includesȱbibliographicalȱreferencesȱandȱindex.ȱ ISBNȱ1Ȭ4051Ȭ1516Ȭ5ȱ(pbk.ȱ:ȱalk.ȱpaper)ȱȱȱ1.ȱRivers.ȱȱȱ2.ȱStreamȱecology.ȱȱȱ3.ȱWatershedȱmanagement.ȱ 4.ȱGeomorphology.ȱȱȱI.ȱFryirs,ȱKirstieȱA.ȱȱȱII.ȱTitle.ȱ ȱ GB1203.2.B755ȱȱ 2005ȱ 551.48’3ȱ–ȱdc22ȱ 2004011686ȱ ȱ ISBNȬ13:ȱ978Ȭ1Ȭ4051Ȭ1516Ȭ2ȱ(pbk.ȱ:ȱalk.ȱpaper)ȱ ȱ AȱcatalogueȱrecordȱforȱthisȱtitleȱisȱavailableȱfromȱtheȱBritishȱLibrary.ȱ ȱ Setȱinȱ9/11ȱTrumpȱMediaevalȱ byȱSNPȱBestȬsetȱTypesetterȱLtd.,ȱHongȱKongȱ PrintedȱandȱboundȱinȱSingaporeȱȱ byȱCOSȱPrintersȱPteȱLtdȱ ȱ Theȱpublisher’sȱpolicyȱisȱtoȱuseȱpermanentȱpaperȱfromȱmillsȱthatȱoperateȱaȱsustainableȱforestryȱpolicy,ȱandȱwhichȱhasȱ beenȱmanufacturedȱfromȱpulpȱprocessedȱusingȱacidȬfreeȱandȱelementaryȱchlorineȬfreeȱpractices.ȱFurthermore,ȱtheȱ publisherȱensuresȱthatȱtheȱtextȱpaperȱandȱcoverȱboardȱusedȱhaveȱmetȱacceptableȱenvironmentalȱaccreditationȱ standards.ȱ ȱ Forȱfurtherȱinformationȱonȱ BlackwellȱPublishing,ȱvisitȱourȱwebsite:ȱ www.blackwellpublishing.comȱ Contents

Preface ix Acknowledgments xi

1 Introduction 1 1.1 Concern for river health 1 1.2 Geomorphic perspectives on ecosystem approaches to river management 4 1.3 What is river restoration? 5 1.4 Determination of realistic goals in river rehabilitation practice 7 1.5 Managing river recovery processes in river rehabilitation practice 9 1.6 Overview of the River Styles framework 11 1.7 Layout and structure of the book 12

PART A The geoecological basis of river management 15

2 Spatial considerations in aquatic ecosystem management 17 2.1 Introduction and chapter structure 17 2.2 Spatial scales of analysis in aquatic geoecology: A nested hierarchical approach 17 2.3 Use of geomorphology as an integrative physical template for river management activities 30 2.4 Working with linkages of biophysical processes 44 2.5 Respect diversity 49 2.6 Summary 52

3 Temporal considerations in aquatic ecosystem management 53 3.1 Chapter structure 53 3.2 Working with river change 53 3.3 Timescales of river adjustment 56 3.4 Interpreting controls on river character and behavior 58 3.5 Predicting the future in fluvial geomorphology 68 3.6 Summary and implications 75

PART B Geomorphic considerations for river management 77

4 River character 79 4.1 Introduction: Geomorphic approaches to river characterization 79 4.2 Channel bed morphology 80 vi Contents

4.3 Bank morphology 93 4.4 Channel morphology: Putting the bed and banks together 104 4.5 Channel size 107 4.6 Floodplain forms and processes 108 4.7 Channel planform 118 4.8 Valley confinement as a determinant of river morphology 134 4.9 Synthesis 142

5 River behavior 143 5.1 Introduction: An approach to interpreting river behavior 143 5.2 Ways in which rivers can adjust: The natural capacity for adjustment 147 5.3 Construction of the river evolution diagram 152 5.4 Bed mobility and bedform development 161 5.5 Adjustments to channel shape 161 5.6 Interpreting channel behavior through analysis of insteam geomorphic units 167 5.7 Adjustments to channel position on the valley floor 176 5.8 Use of geomorphic units as a unifying attribute to assess river behavior 184 5.9 Synthesis 185

6 River change 186 6.1 Introduction 186 6.2 Framing river evolution in context of Late Quaternary climate change 187 6.3 The nature of river change 188 6.4 Framing river change on the river evolution diagram 191 6.5 The spatial distribution of river change 196 6.6 Temporal perspectives of river change 200 6.7 Appraising system vulnerability to change 202

7 Geomorphic responses of rivers to human disturbance 208 7.1 Introduction: Direct and indirect forms of human disturbance to rivers 208 7.2 Direct human-induced changes to river forms and processes 210 7.3 Indirect river responses to human disturbance 220 7.4 Spatial and temporal variability of human impacts on rivers 225 7.5 (Ir)reversibility and the river evolution diagram revisited 232 7.6 Synopsis 238

PART C The River Styles framework 241

8 Overview of the River Styles framework and practical considerations for its application 243 8.1 Moves towards a more integrative river classification scheme 243 8.2 What is the River Styles framework? 244 8.3 Scale and resolution in practical application of the River Styles framework 249 8.4 Reservations in use of the River Styles framework 251

9 Stage One of the River Styles framework: Catchment-wide baseline survey of river character and behavior 254 9.1 Introduction 254 9.2 Stage One, Step One: Regional and catchment setting analyses 254 Contents vii

9.3 Stage One, Step Two: Definition and interpretation of River Styles 261 9.4 Stage One, Step Three: Assess controls on the character, behavior, and downstream patterns of River Styles 287 9.5 Overview of Stage One of the River Styles framework 292

10 Stage Two of the River Styles framework: Catchment-framed assessment of river evolution and geomorphic condition 297 10.1 Introduction 297 10.2 Stage Two, Step One: Determine the capacity for adjustment of the River Style 300 10.3 Stage Two, Step Two: Interpret river evolution to assess whether irreversible geomorphic change has occurred and identify an appropriate reference condition 302 10.4 Stage Two, Step Three: Interpret and explain the geomorphic condition of the reach 316 10.5 Products of Stage Two of the River Styles framework 323

11 Stage Three of the River Styles framework: Prediction of likely future river condition based on analysis of recovery potential 324 11.1 Introduction 324 11.2 Stage Three, Step One: Determine the trajectory of change 327 11.3 Stage Three, Step Two: Assess river recovery potential: Place reaches in their catchment context and assess limiting factors to recovery 330 11.4 Products of Stage Three of the River Styles framework 341

12 Stage Four of the Rivers Styles framework: Implications for river management 342 12.1 Introduction: River rehabilitation in the context of river recovery 342 12.2 Stage Four, Step One: Develop a catchment-framed physical vision 342 12.3 Stage Four, Step Two: Identify target conditions for river rehabilitation and determine the level of intervention required 349 12.4 Stage Four, Step Three: Prioritize efforts based on geomorphic condition and recovery potential 349 12.5 Stage Four, Step Four: Monitor and audit improvement in geomorphic river condition 353 12.6 Products of Stage Four of the River Styles framework 354

13 Putting geomorphic principles into practice 355 13.1 Introduction 355 13.2 Geomorphology and environmental science 355 13.3 Geomorphology and river management: Reading the landscape to deveop practices that work with river diversity and dynamism 357 13.4 The river management arena 358 13.5 Use of the River Styles framework in geomorphology and river management 362

References 364 Index 387

Preface: our personal, Australian, perspectives

Every country has its own landscape which deposits itself in layers on the consciousness of its citizens, thereby canceling the exclusive claims made by all other landscapes. Murray Bail, 1998, p. 23

Any book reflects the personal histories and as- Along with its unique environmental setting sociated geographic and cultural values of its and history of human disturbance, a distinctive authors. In a number of ways it is increasingly dif- approach to natural resources management that ficult for us to separate our scientific perspective is characterized by extensive on-the-ground in- on rivers and their management from an emotion- volvement of community groups has developed al and aesthetic bond that has developed in our in Australia. Rehabilitation strategies imple- work. Working within a conservation ethos, we mented through Catchment Management promote a positive sense of what can be achieved Committees (or Authorities/Trusts), Landcare through effective implementation of rehabilita- Groups, Rivercare Groups, etc. have been comple- tion practices. mented by core support through Federal and State Perspectives conveyed in this book undoubtedly Government programs. Adoption of participatory reflect, to some degree, the distinctive nature of rather than regulatory approaches to river manage- the Australian landscape and biota, the recent yet ment has presented significant opportunity to profound nature of disturbance associated with incorporate research ideas into management colonial settlement, and community involvement practice. in river conservation and rehabilitation practices. Uptake of rehabilitation programs that strive to The long and slow landscape evolution of the heal river systems in Australia has been driven by Australia landmass has resulted in rivers with extensive involvement and leadership from the a distinctive character and behavior, driven by small group of professional geomorphologists in factors such as the relative tectonic stability and the country. A significant collection of tools topographic setting of the continent, pronounced and techniques for river rehabilitation has been discharge variability, and limited material avail- provided, including the National Stream Re- ability. Remarkably few river systems comprise habilitation Guide (Rutherfurd et al., 2000), the truly alluvial, self-adjusting streams. Many con- National Stream Restoration Framework (Koehn temporary river forms and processes have been in- et al., 2001), and proceedings from various Stream fluenced by antecedent landscape controls, such as Management Conferences (Rutherfurd and the nature of the bedrock or older alluvial materi- Walker, 1996; Rutherfurd and Bartley, 1999; als over which they flow, and generally limited Rutherfurd et al., 2001b). Our efforts in writing relief. Given the nature of the environmental set- this book have been aided enormously by this in- ting, it is scarcely surprising that the Australian vigorating set of research products, and the dedica- landscape is characterized by an array of river tion of various river practitioners who have “made forms and processes that is seldom observed else- this happen.” where. Across much of the continent, human dis- In our quest to develop a logical set of principles turbance has left a profound “recent” imprint on with which to interpret the diversity and complex- this largely ancient landscape, the consequences ity of the real world, we have tried to communicate of which vary markedly from system to system our understanding in as simple a way as possible. (e.g. Rutherfurd, 2000). Duplications, inaccuracies, and inconsistencies x Preface may have arisen in cross-disciplinary use of terms, book bears little semblance of reality in terms of but hopefully we provide a useful platform that the types of rivers you live and/or work with. aids uptake and implementation of geomorphic However, we hope that the principles presented principles in river rehabilitation practice. here bear relevance to the management issues that Although this book has an unashamedly you face, and that the book provides useful guid- Australian flavor, we have endeavored to write it ance in the development of core understanding from a global perspective. We convey our apolo- that is required if management activities are to gies, in advance, to those readers to whom this yield sustainable outcomes. Acknowledgments

The River Styles framework has its origins in river Coast Catchment Management Committee, reach analysis of the Waiau River in New Zealand, under leadership by Kerry Pfeiffer and funding in a project coordinated through Southland generated through the Bega Valley Shire and the Regional Council, following a flash of inspiration Natural Heritage Trust (NHT). Various workshops generated by Glen Lauder. In 1994, Gary Brierley and reports promoted early findings of the work. was invited to South Africa to participate in a river At one of these meetings, Michael Pitt and various health workshop coordinated by Barry Hart (from colleagues from the North Coast Office of DLWC the Australian half of the gathering). This built on envisaged potential applications of equivalent initial contacts suggested by Brian Finlayson, who work in their catchments. Tony Broderick played a recommended an approach be made to a Federal pivotal part in facilitating these applications. At Government body, the Land and Water Resources this stage, Rob Ferguson, Ivars Reinfelds, and Guy Research and Development Corporation (now Lampert extended the range of rivers to which the Land and Water Australia; LWA) to seek support to work was applied through characterizations of continue this work. The award of a substantive rivers in the Manning catchment. The primary grant effectively marked the birth of the River role of differing forms of valley confinement, Styles framework. Phil Price provided invaluable which formed a part of the PhD work completed by guidance in these initial endeavors – his broaden- Rob Ferguson, advanced the framework. ing of scope ensured that a generic, open-ended ap- Subsequent developments included research on proach was developed, moving beyond a case study stream power along longitudinal profiles in the perspective. Further backing by Siwan Lovett and Bellinger catchment, in work completed with Tim Nick Schofield in LWA aided the coordination Cohen and Ivars Reinfelds. Insights into geological of early work. Collaboration with Tim Cohen, controls on patterns of River Styles was provided Sharon Cunial, and Fiona Nagel fashioned initial by Geoff Goldrick, in application of this work in endeavors, with willing sounding boards on hand the Richmond catchment. Eventually more than at Macquarie University in discussions with 10 catchment-based reports characterized the Andrew Brooks, John Jansen, and Rob Ferguson. diversity of River Styles and their downstream Substantive external support through the State patterns, in all North Coast catchments extending Government agency, then called the Department from the Hastings to the Tweed. Rob Ferguson of Land and Water Conservation (DLWC), was coordinated this work, with field work completed generated at the outset of the project. Head Office by Guy Lampert. Paul Batten provided the initial leadership was guided by David Outhet, and on- algorithms to generate longitudinal profiles and the-ground support in the Bega Regional Office, stream power plots through use of Geographic initially by Justin Gouvernet and Don McPhee and Information Systems and Digital Elevation substantially with Cliff Massey. The practical Models. Paula Crighton was invaluable in refining development and application of the River Styles this procedure and processing the data for the work in Bega catchment was enormously en- North Coast catchments. Practical application hanced by collaboration with the former Far South of the work was enhanced through a subsequent xii Acknowledgments contract in the Shoalhaven catchment where and postgraduate students, including Ted Hickin, Rachel Nanson completed much of the field work. Malcolm Newson, Jonathan Phillips, Rob Fer- A major advancement in the development of the guson, Jo Hoyle, Nick Preston, and John Spencer. River Styles framework occurred with extensions These review comments substantially improved from assessment of river character and behavior to the clarity and communicability of the book. analyses of river condition and recovery potential. Teaching River Styles Short Courses has oc- The PhD work of Kirstie Fryirs developed these curred in parallel to development of the framework. procedures and applied them in the Bega catch- We wish to thank the participants of these courses, ment. These procedures now form Stages 2 and who have spanned a wide range of professions and 3 of the framework. The development of these levels of experience from around the nation and procedures was enhanced by a visit to Australia by overseas. Their contributions have improved the Scott Babakaiff (funded by LWA) and development presentation of the River Styles framework and of the National River Restoration Framework (in a our ability to communicate and teach it. Each project with John Koehn and Belinda Cant funded River Styles Short Course has been run through by LWA). Macquarie Research Limited (MRL) with adminis- The next phase of the River Styles work entailed trative support from Roslyn Green, Kerry Tilbrook, fundamental research into ecological (habitat) and Sophie Beauvais. Sophie Beauvais, Irina associations with a geomorphic classification Zakoshanski, and Warren Bailey are thanked for scheme. This work was completed by two Post- their support in administering developments of Docs (Mark Taylor and Jim Thomson), through the framework, promotion, trade-marking, and collaborative funding provided by LWA and accreditation of the framework. The term River DLWC. Penny Knights and Glenda Orr supported Styles® is a registered trademark held by Mac- this work. Collaboration with Bruce Chessman quarie University and Land and Water Australia. linked geomorphology and ecology in assessments Most of the graphics in this book were designed of geoecological condition in Bega catchment. by Kirstie Fryirs and drafted by Dean Oliver Since its creation, promotion and adoption of the Graphics, Pty Ltd. We thank Dean for his commit- River Styles framework has occurred across the na- ment to this project. We also thank colleagues in tion. Particular mention must be made of David the Department of Physical Geography, Macquarie Outhet, who promoted the adoption of the frame- University for their support. work as a tool for management activities in New Sincere thanks to Sue and Paul Gebauer who own South Wales, and provided numerous insightful Wonga Wildlife Retreat in Coffs Harbour. They comments on its application. Sally Boon in provided us with a writer’s paradise. Without Queensland and David Wright in Tasmania have Wonga the book would not be what it is today. We also promoted the framework and have sourced also extend our thanks to Chris and Rick Fryirs for funding for us to run courses and workshops in use of their Woodford house during the postreview those states. stage. Numerous members of the Rivers Group at We extend our love to our families for their pa- Macquarie University have provided many hours tience and support over the many years it has taken of enthusiastic and fruitful discussion about to write this book; Emmy, Zac, Whit, Chris, Rick, rivers. While most now roam further afield, they Steve, Sarah, Tim, Dee, Chris – thank you! remain a large part of the “history” associated with Self-evidently, many people have helped us along this book. Particular mention must be made of the way in a process that has provided many intel- Andrew Brooks, Tim Cohen, Rob Ferguson, John lectual and personal challenges. Their insight and Jansen, Emily Cracknell, Paula Crighton, Mick support have encouraged us to “maintain the Hillman, Pete Johnston, and Kahli McNab. Mick rage,” during countless phases when the project Hillman, in particular, provided the stimulus for didn’t quite want to come to fruition. Indeed, we greatly enhancing the ‘extension science’ compo- hope the book is far from an endpoint. As in any nent of our work. book, ultimate responsibility in ideas presented lie Insightful and constructive review comments with the authors. Our apologies, in advance, to any- on this book were made by a range of academics one whose thoughts have been misrepresented. CHAPTER 1

Introduction

Society’s ability to maintain and restore the integrity of aquatic ecosystems requires that conservation and management actions be firmly grounded in scientific understanding. LeRoy Poff, et al., 1997, p. 769

1.1 Concern for river health tems. Issues such as habitat loss, degradation, and fragmentation have resulted in significant Rivers are a much-cherished feature of the natural concerns for ecological integrity, sustainability, world. They perform countless vital functions in and ecosystem health. As awareness and under- both societal and ecosystem terms, including per- standing of these issues has improved, society no sonal water consumption, health and sanitation longer has an excuse not to address concerns needs, agricultural, navigational, and industrial brought about by the impacts of human activities uses, and various aesthetic, cultural, spiritual, and on river systems. Shifts in environmental atti- recreational associations. In many parts of the tudes and practice have transformed outlooks world, human-induced degradation has profound- and actions towards revival of aquatic ecosystems. ly altered the natural functioning of river systems. Increasingly, management activities work in Sustained abuse has resulted in significant alarm harmony with natural processes in an emerg- for river health, defined as the ability of a river and ing “age of repair,” in which contemporary its associated ecosystem to perform its natural management strategies aim to enhance fluvial functions. In a sense, river health is a measure of environments either by returning rivers, to some catchment health, which in turn provides an indi- degree, to their former character, or by establishing cation of environmental and societal health. It is a new, yet functional environment. Notable increasingly recognized that ecosystem health is improvements to river health have been achieved integral to human health and unless healthy rivers across much of the industrialized world in are maintained through ecologically sustainable recent decades. However, significant community practices, societal, cultural, and economic values and political concern remains over issues such are threatened and potentially compromised. as flow regulation, algal blooms, salinity, loss Viewed in this way, our efforts to sustain healthy, of habitat and species diversity, erosion and living rivers provide a measure of societal health sedimentation problems, and water resource and our governance of the planet on which we live. overallocation. It is scarcely surprising that concerns for river con- Rivers demonstrate a remarkable diversity of dition have been at the forefront of conservation landform patterns, as shown in Figure 1.1. Each of and environmental movements across much of the the rivers shown has a distinct set of landforms and planet. its own behavioral regime. Some rivers have sig- In the past, the quest for security and stability nificant capacity to adjust their form (e.g., the me- to meet human needs largely overlooked the needs andering, anastomosing, and braided river types), of aquatic ecosystems. In many instances, human while others have a relatively simple geomorphic activities brought about a suite of unintended structure and limited capacity to adjust (e.g., the and largely unconsidered impacts on river health, chain-of-ponds and gorge river types). This vari- compromising the natural variability of rivers, ability in geomorphic structure and capacity to ad- their structural integrity and complexity, and just, which reflects the array of landscape settings the maintenance of functioning aquatic ecosys- in which these rivers are found, presents signifi- 2 Chapter 1

Figure 1.1 The diversity of river morphology Rivers are characterized by a continuum of morphological diversity, ranging from bedrock controlled variants such as (a) gorges (with imposed sets of landforms), to fully alluvial, self-adjusting rivers such as (c) braided and (d) meandering variants (with various midchannel, bank-attached and floodplain features). Other variants include multichanneled anastomosing rivers that form in wide, low relief plains (e), and rivers with discontinuous floodplain pockets in partly-confined valleys (b). In some settings, channels are discontinuous or absent, as exemplified by chain-of-ponds (f). Each river type has a different capacity to adjust its position on the valley floor. (a) Upper Shoalhaven catchment, New South Wales, Australia, (b) Clarence River, New South Wales, Australia, (c) Rakaia River, New Zealand, (d) British Columbia, Canada, (e) Cooper Creek, central Australia, and (f) Murrumbateman Creek, New South Wales, Australia. Introduction 3 cant diversity in the physical template atop which looking after good condition remnants of river ecological associations have evolved. courses, and seeking to sustain rare or unique Developing a meaningful framework to recog- reaches of river regardless of their condition. nize, understand, document, and maintain this Just as there is remarkable diversity of river geodiversity is a core theme of this book. Working forms and processes in the natural world, so within a conservation ethos, emphasis is placed on human-induced disturbance to rivers is equally the need to maintain the inherent diversity of variable (see Figure 1.2). Many of these actions riverscapes and their associated ecological values. have been intentional, such as dam construction, Adhering to the precautionary principle, the high- channelization, urbanization, and gravel or sand est priority in management efforts is placed on extraction. Far more pervasive, however, have

Figure 1.2 Human modifications to river courses Human modifications to rivers include (a) dams (Itaipu Dam, Brazil), (b) channelization (Ishikari River, Japan), (c) urban stream (Cessnock, New South Wales, Australia), (d) native and exotic vegetation removal (Busby’s Creek, Tasmania, Australia), (e) gravel and sand extraction (Nambucca River, New South Wales, Australia), and (f) mine effluent (King River, Tasmania, Australia). 4 Chapter 1 been inadvertent changes brought about through resources management, river rehabilitation pro- adjustments to flow and sediment transfer regimes grams apply multidisciplinary thinking to address associated with land-use changes, clearance of ri- concerns for biodiversity and ecosystem integrity parian vegetation, etc. Across much of the planet, (Sparks, 1995). Inevitably, the ultimate goals of remarkably few river systems even approximate these applications are guided by attempts to bal- their pristine condition. Most rivers now operate ance social, economic, and environmental needs, as part of highly modified landscapes in which and they are constrained by the existing hydrologi- human activities are dominant. cal, water quality, and sediment transport regimes The innate diversity of river courses is a source of any given system (Petts, 1996). Ultimately, how- of inspiration, but it presents many perplexing ever, biophysical considerations constrain what challenges in the design and implementation of can be achieved in river management. If river sustainable management practices. Unless man- structure and function are undermined, such that agement programs respect the inherent diversity the ecological integrity of a river is compromised, of the natural world, are based on an understanding what is left? River rehabilitation programs framed of controls on the nature and rate of landscape in terms of ecological integrity must build on prin- change, and consider how alterations to one part ciples of landscape ecology. The landscape con- of an ecosystem affect other parts of that system, text, manifest through the geomorphic structure efforts to improve environmental condition are and function of river systems, provides a coherent likely to be compromised. River management pro- template upon which these aspirations must be grams that work with natural processes will likely grounded. The challenge presented to geomor- yield the most effective outcomes, in environmen- phologists is to construct a framework with which tal, societal, and economic terms. Striving to meet to meaningfully describe, explain, and predict the these challenges, truly multifunctional, holistic, character and behavior of aquatic ecosystems. catchment-scale river management programs Biological integrity refers to a system’s whole- have emerged in recent decades (e.g., Gardiner, ness, including presence of all appropriate biotic 1988; Newson, 1992a; Hillman and Brierley, in elements and occurrence of all processes and inter- press). Procedures outlined in this book can be actions at appropriate scales and rates (Angermeier used to determine realistic goals for river restora- and Karr, 1994). This records a system’s ability tion and rehabilitation programs, recognizing the to generate and maintain adaptive biotic ele- constraints imposed by the nature and condition of ments through natural evolutionary processes. river systems and the cultural, institutional, and Ecosystem integrity requires the maintenance of legal frameworks within which these practices both physico-chemical and biological integrity, must be applied. maintaining an appropriate level of connectivity between hydrological, geomorphic, and biotic processes. While loss of biological diversity is tra- 1.2 Geomorphic perspectives on ecosystem gic, loss of biological integrity includes loss of di- approaches to river management versity and breakdown in the processes necessary to generate future diversity (Angermeier and Karr, Rivers are continuously changing ecosystems that 1994). Endeavors to protect ecological integrity re- interact with the surrounding atmosphere (climat- quire increased reliance on preventive rather than ic and hydrological factors), biosphere (biotic fac- reactive management, and a focus on landscapes tors), and earth (terrestrial or geological factors). rather than populations. Increasing recognition that ecosystems are open, In riparian landscapes, aquatic, amphibious, and nondeterministic, heterogeneous, and often in terrestrial species have adapted to a shifting mosa- nonequilibrium states, is prompting a shift in ic of habitats, exploiting the heterogeneity that management away from maintaining stable sys- results from natural disturbance regimes (Junk tems for particular species to a whole-of-system et al., 1989; Petts and Amoros, 1996; Naiman and approach which emphasizes diversity and flux Decamps, 1997; Ward et al., 2002). This mosaic in- across temporal and spatial scales (Rogers, 2002). cludes surface waters, alluvial aquifers, riparian Working within an ecosystem approach to natural vegetation associations, and geomorphic features Introduction 5

(Tockner et al., 2002). Because different organisms across a catchment is integral to proactive river have different movement capacities and different management. This book outlines a generic set of habitat ranges, their responses to landscape het- procedures by which this understanding can be erogeneity differ (Wiens, 2002). Fish diversity, for achieved. example, may peak in highly connected habitats, Rehabilitation activities must be realistically whereas amphibian diversity tends to be highest in achievable. Most riverscapes have deviated some habitats with low connectivity (Tockner et al., way from their pristine, predisturbance condition. 1998). Other groups attain maximum species rich- Hence, practical management must appraise what ness between these two extremes. The resulting is the best that can be achieved to improve the pattern is a series of overlapping species diversity health of a system, given the prevailing boundary peaks along the connectivity gradient (Ward et al., conditions under which it operates. In instances 2002). Given the mutual interactions among where human changes to river ecosystems are irre- species at differing levels in the food chain, ecosys- versible or only partially reversible, a pragmatic tem functioning reflects the range of habitats in definition of ecological integrity refers to the any one setting and their connectivity. maintenance of a best achievable condition that Landscape ecology examines the influence of contains the community structure and function spatial pattern on ecological processes, consider- that is characteristic of a particular locale, or a ing the ecological consequences of where things condition that is deemed satisfactory to society are located in space, where they are relative to (Cairns, 1995). Specification of the goals of river other things, and how these relationships and their management, in general, and river restoration, in consequences are contingent on the characteris- particular, has provoked considerable discussion, tics of the surrounding landscape mosaic. The pat- as highlighted in the following section. tern of a landscape is derived from its composition (the kinds of elements it contains), its structure (how they are arranged in space), and its behavior 1.3 What is river restoration? (how it adjusts over time; Wiens, 2002). A land- scape approach to analysis of aquatic ecosystems The nature and extent of river responses to human offers an appropriate framework to elucidate the disturbance, and the future trajectory of change, links between pattern and process across scales, constrain what can realistically be achieved in to integrate spatial and temporal phenomena, to river management (Figure 1.3; Boon, 1992). At one quantify fluxes of matter and energy across envi- extreme, conservation goals reflect the desire to ronmental gradients, to study complex phenome- preserve remnants of natural or near-intact sys- na such as succession, connectivity, biodiversity, tems. Far more common, however, are endeavors and disturbance, and to link research with man- to rectify and repair some (or all) of the damage to agement (Townsend, 1996; Tockner et al., 2002; river ecosystems brought about by human activi- Ward et al., 2002; Wiens, 2002). ties. Various terms used to describe these goals and Principles from fluvial geomorphology provide a activities can be summarized using the umbrella physical template with which to ground landscape term “restoration.” perspectives that underpin the ecological integrity Restoration means different things to different of river systems. Although landscape forms and people, the specific details of which may promote processes, in themselves, cannot address all con- considerable debate and frustration (Hobbs and cerns for ecological sustainability and biodiversity Norton, 1996). Although the term has been applied management, these concerns cannot be meaning- to a wide range of management processes/activi- fully managed independent from geomorphologi- ties, its precise meaning entails the uptake of cal considerations. Working from the premise that measures to return the structure and function of a concerns for ecological integrity are the corner- system to a previous state (an unimpaired, pris- stone of river management practice, and that land- tine, or healthy condition), such that previous scape considerations underpin these endeavors, attributes and/or values are regained (Bradshaw, interpretation of the diversity, patterns, and 1996; Higgs, 2003). In general, reference is made to changing nature of river character and behavior predisturbance functions and related physical, 6 Chapter 1

Figure 1.3 Framing realistic management options – what can be realistically achieved? Determination of river rehabilitation goals is constrained primarily by what it is realistically possible to achieve. This reflects system responses to human disturbance, the prevailing set of boundary conditions, and the likely future trajectory of change (as determined by limiting factors and pressures operating within the catchment and societal goals). Maintenance of an intact condition is a conservation goal. If a return to a predisturbance state is possible and desirable, rehabilitation activities can apply recovery principles to work towards a restoration goal. In many instances, adoption of a creation goal, which refers to a new condition that previously did not exist at the site, is the only realistic option.

chemical, and biological characteristics (e.g., restoration refers to the process of assisting the re- Cairns, 1991; Jackson et al., 1995; Middleton, covery of an ecosystem that has been degraded, 1999). damaged, or destroyed. The notion of recovery de- The few studies that have documented geomor- scribes the process of bringing something back. phic attributes of relatively intact or notionally Endeavors that assist a system to adjust towards pristine rivers (e.g., Collins and Montgomery, a less stressed state, such that there is an improve- 2001; Brooks and Brierley, 2002), and countless ment in condition, are more accurately referred to studies that have provided detailed reconstruc- as river rehabilitation. Rehabilitation can mean tions of river evolution over timescales of decades, the process of returning to a previous condition or centuries, or longer, indicate just how profound status along a restoration pathway, or creation of a human-induced changes to river forms and new ecosystem that previously did not exist (Fryirs processes have been across most of the planet. It is and Brierley, 2000; Figure 1.3). In landscapes sub- important to remember the nonrepresentative na- jected to profound human disturbance, such as ture of the quirks of history that have avoided the urban, industrial, or intensively irrigated areas, profound imprint of human disturbance. Intact management activities inevitably work towards reaches typically lie in relatively inaccessible creation goals. Both restoration and creation goals areas. They are seldom representative of the areas require rehabilitation strategies that strive to im- in which management efforts aim to improve river prove river condition, applying recovery notions to health. However, it is in these reaches, and work towards the best attainable ecosystem values adjacent good condition reaches, that efforts at given the prevailing boundary conditions. The es- restoration can meaningfully endeavor to attain sential difference between restoration and cre- something akin to the pure definition of the word. ation goals lies in the perspective of regenerating Viewed in a more general sense, restoration the “old” or creating a “new” system (Higgs, 2003). refers to a management process that provides a Various other terms have been used to character- means to communicate notions of ecosystem re- ize practices where the goals are not necessarily covery (Higgs, 2003). For example, the Society for framed in ecosystem terms. For example, reclama- Ecological Restoration (SERI, 2002) state that tion refers to returning a river to a useful or proper Introduction 7 state, such that it is rescued from an undesirable Unlike many biotic characteristics, physical condition (Higgs, 2003). In its original sense, recla- habitat is directly amenable to management mation referred to making land fit for cultivation, through implementation of rehabilitation pro- turning marginal land into productive acreage. grams (Jacobson et al., 2001). Hence, many man- Alternatively, remediation refers to the process of agement initiatives focus on physical habitat repairing ecological damage in a manner that does creation and maintenance, recognizing that not focus on ecological integrity and is typically geomorphic river structure and function and applied without reference to historical conditions vegetation associations must be appropriately (Higgs, 2003). Reclamation and remediation are reconstructed before sympathetic rehabilitation quick-fix solutions to environmental problems of riverine ecology will occur (Newbury and that address concerns for human values, viewed Gaboury, 1993; Barinaga, 1996). Getting the geo- separately from their ecosystem context. morphological structure of rivers right maximizes The purpose and motivation behind any rehabil- the ecological potential of a reach, in the hope that itation activity are integral to the goal sought. improvements in biological integrity will follow Specification of conservation, restoration, or cre- (i.e., the “field of dreams” hypothesis; Palmer et ation goals provides an indication of the level and al., 1997). The simplest procedure with which to type of intervention that is required to improve determine a suitable geomorphic structure and riverine environments. function is to replicate the natural character of “healthy” rivers of the same “type,” analyzed in equivalent landscape settings. 1.4 Determination of realistic goals in river In any management endeavor, it is imperative to rehabilitation practice identify, justify, and communicate underlying goals, ensuring that the tasks and plan of action are The process of river rehabilitation begins with a visionary yet attainable. Although setting goals for judgment that an ecosystem damaged by human rehabilitation is one of the most important steps in activities will not regain its former characteristic designing and implementing a project, it is often properties in the near term, and that continued either overlooked entirely or not done very well degradation may occur (Jackson et al., 1995). (Hobbs, 2003). Success can only be measured if a Approaches to repair river systems may focus on definitive sense is provided of what it will look rehabilitating “products” (species or ecosystems) like. Unfortunately, however, there is a tendency directly, or on “processes” which generate the de- to jump straight to the “doing” part of a project sired products (Neimi et al., 1990; Richards et al., without clearly articulating the reasons why 2002). However, unless activities emphasize things are being done and what the outcome concerns for the rehabilitation of fundamental should be (Hobbs, 1994, 2003). processes by which ecosystems work, notions of While sophisticated methodologies and tech- ecosystem integrity and related measures of biodi- niques have arisen in the rapidly growing field of versity may be compromised (Cairns, 1988). rehabilitation management, the conceptual foun- The goal of increasing heterogeneity across the dations of much of this work remain vague spectrum of river diversity represents a flawed per- (Ebersole et al., 1997). The pressure of timeframes, ception of ecological diversity and integrity. In tangible results, and political objectives has lead some cases, the “natural” range of habitat struc- to a preponderance of short-term, transitory re- ture may be very simple. Hence, heterogeneity or habilitation projects that ignore the underlying geomorphic complexity does not provide an appro- capacities and developmental histories of the priate measure of river health (see Fairweather, systems under consideration, and seldom place 1999). Simplistic goals framed in expressions such the study/treatment reach in its catchment con- as “more is better” should be avoided (Richards et text (Ebersole et al., 1997; Lake, 2001a, b). al., 2002). Use of integrity as a primary manage- Unfortunately, many of these small-scale aquatic ment goal avoids the pitfalls associated with habitat enhancement projects have failed, or have assumptions that greater diversity or productiv- proven to be ineffective (e.g., Frissell and Nawa, ity is preferred. 1992). 8 Chapter 1

Ensuring that goals are both explicit enough to full range of expected or appropriate structures and be meaningful and realistic enough to be achiev- processes for that type of river under prevailing able is a key to the development of successful pro- catchment boundary conditions. This does not jects. Ideally, goals are decided inclusively, so that necessarily equate to a predisturbance state, as everyone with an interest in the outcomes of the human impacts may have altered the nature, rate, project agrees with them (Hobbs, 2003). Scoping and extent of river adjustments (Cairns, 1989). the future and generating a realistic vision of the Second, a dynamically adjusted reach does not nec- desired river system are critical components of the essarily equate to an equilibrium state. Rather, the planning process. The vision should be set over a river adjusts to disturbance via flow, sediment, and 50 year timeframe (i.e., 1–2 generations; Jackson et vegetation interactions that fall within the natural al., 1995), such that ownership of outcomes can be range of variability that is deemed appropriate for achieved. A vision must be based on the best avail- the type of river under investigation. able information on the character, behavior, and Determination of appropriate reference condi- evolution of the system, providing a basis to inter- tions, whether a fixed historical point in time or pret the condition and trajectory of change from a suite of geoecological conditions, represents a which desired future conditions can be established critical challenge in rehabilitation practice (Higgs, (Brierley and Fryirs, 2001). These concepts must be 2003). Systems in pristine condition serve as a tied to analysis of biophysical linkages across a point of reference rather than a prospective goal for range of scales, enabling off-site impacts and river rehabilitation projects, although attributes of lagged responses to disturbance events and/or re- this ideal condition may be helpful in rehabilita- habilitation treatments to be appraised (Boon, tion design. Identification of reference conditions 1998). aids interpretation of the rehabilitation potential To maximize effectiveness, rehabilitation ef- of sites, thereby providing a basis to measure the forts should incorporate spatiotemporal scales success of rehabilitation activities. that are large enough to maintain the full range Reference conditions can be determined on the of habitats and biophysical linkages necessary for basis of historical data (paleo-references), data de- the biota to persist under the expected distur- rived from actual situations elsewhere, knowledge bance regime or prevailing boundary conditions. about system structure and functioning in general Although emphasis may be placed on a particular (theoretical insights), or a combination of these component or attribute, ultimate aims of long- sources (Petts and Amoros, 1996; Jungwirth et al., term projects should focus on the whole system at 2002; Leuven and Poudevigne, 2002). The morpho- the catchment scale (Bradshaw, 1996). Desired logical configuration and functional attributes of a conditions for each reach should be specified as reference reach must be compatible with prevail- conservation, restoration, or creation goals, indi- ing biophysical fluxes, such that they closely cating how they fit within the overall catchment equate to a “natural” condition for the river type. vision. Appropriate reference conditions should be Ideally, reference reaches are located in a similar specified for each reach. position in the catchment and have near equiva- Defining what is “natural” for a given type of lent channel gradient, hydraulic, and hydrologic river that operates under a certain set of prevailing conditions (Kondolf and Downs, 1996). boundary conditions provides an important step in Unfortunately, it is often difficult to find appropri- identification of appropriate reference conditions ate reference conditions for many types of river, against which to measure the geoecological in- as “natural” or minimally impacted reaches no tegrity of a system and to identify target conditions longer exist (Henry and Amoros, 1995; Ward et al., for river rehabilitation. A “natural” river is defined 2001). In the absence of good condition remnants, here as “a dynamically adjusting system that be- reference conditions can be constructed from his- haves within a given range of variability that is torical inferences drawn from evolutionary se- appropriate for the river type and the boundary quences that indicate how a river has adjusted over conditions under which it operates.” Within this an interval of time during which boundary condi- definition, two points of clarification are worth tions have remained relatively uniform. Selection noting. First, a “natural” condition displays the of the most appropriate reference condition is situ- Introduction 9 ated within this sequence. Alternatively, a suite of the river to self-adjust (cf., Hooke, 1999; Fryirs and desirability criteria derived for each type of river Brierley, 2000; Parsons and Gilvear, 2002; Simon can be used to define a natural reference condition and Darby, 2002). Although these measures entail against which to compare other reaches (Fryirs, minimal intervention and cost, managers have 2003). These criteria must encapsulate the forms negligible control over the characteristics and and processes that are “expected” or “appropriate” functioning of habitats (Jacobson et al., 2001). for the river type. They draw on system-specific In general terms, however, most contemporary and process-based knowledge, along with findings approaches to river rehabilitation endeavor to from analysis of river history and assessment of “heal” river systems by enhancing natural recov- available analogs. This approach provides a guid- ery processes (Gore, 1985). Assessment of geomor- ing image, or Leitbild, of the channel form that phic river recovery is a predictive process that is would naturally occur at the site, adjusted to ac- based on the trajectory of change of a system in re- count for irreversible changes to controlling fac- sponse to disturbance events. Recovery enhance- tors (such as runoff regime) and for considerations ment involves directing reach development along based on cultural ecology (such as preservation of a desired trajectory to improve its geomorphic con- existing land uses or creation of habitat for endan- dition over a 50–100 year timeframe (Hobbs and gered species; Kern, 1992; Jungwirth et al., 2002; Norton, 1996; Fryirs and Brierley 2000; Brierley Kondolf et al., 2003). Leitbilds can be used to pro- et al., 2002). To achieve this goal, river rehabilita- vide a reference network of sites of high ecological tion activities must build on an understanding of status for each river type, as required by the the stage and direction of river degradation and/or European Union Water Framework Directive. recovery, determining whether the geomorphic condition of the river is improving, or continuing to deteriorate. 1.5 Managing river recovery processes in river Assessment of geomorphic river condition rehabilitation practice measures whether the processes that shape river morphology are appropriate for the given setting, Exactly what is required in any rehabilitation ini- such that deviations from an expected set of attrib- tiative will depend on what is wrong. Options may utes can be appraised (Figure 1.4; Kondolf and range from limited intervention and a leave-alone Larson, 1995; Maddock, 1999). Key consideration policy, to mitigation or significant intervention, must be given to whether changes to the boundary depending on how far desired outcomes are from conditions under which the river operates have the present condition. In some instances, sensi- brought about irreversible changes to river struc- tive, critical, or refuge habitats, and the stressors ture and function (Fryirs, 2003). Identification or constraints that limit desirable habitat, must of good condition reaches provides a basis for be identified, and efforts made to relieve these their conservation. Elsewhere, critical forms and stressors or constraints (Ebersole et al., 1997). processes may be missing, accelerated, or anom- Controlling factors that will not ameliorate natu- alous, impacting on measures of geoecological rally must be identified, and addressed first. functioning. Elsewhere, rehabilitation may involve the reduc- Understanding of geomorphic processes and tion, if not elimination, of biota such as successful their direction of change underpins rehabilitation invaders, in the hope of favoring native biota strategies that embrace a philosophy of recovery (Bradshaw, 1996). For a multitude of reasons, rang- enhancement (Gore, 1985; Heede and Rinne, 1990; ing from notions of naturalness that strive to pre- Milner, 1994). Helping a river to help itself pres- serve “wilderness,” to abject frustration at the ents an appealing strategy for river rehabilitation inordinate cost and limited likelihood of success activities because they cost nothing in themselves in adopted measures (sometimes referred to as bas- (although they may cost something to initiate), ket cases, or “raising the Titanic”; Rutherfurd they are likely to be self-sustaining because they et al., 1999), it is sometimes advisable to pursue a originate from within nature (although they may passive approach to rehabilitation. This strategy, need nurturing in some situations), and they can often referred to as the “do nothing option,” allows be applied on a large scale (Bradshaw, 1996). Design 10 Chapter 1

Figure 1.4 Habitat diversity for good, moderate, and poor condition variants of the same river type Natural or expected character and behavior varies for differing types of river. Some may be relatively complex, others are relatively simple. Natural species adaptations have adapted to these conditions. Assessments of geomorphic river condition must take this into account, determining whether rehabilitation activities should increase (a) or decrease (b) the geomorphic heterogeneity of the type of river under investigation. Increasing geomorphic heterogeneity is not an appropriate goal for all types of river, and may have undesirable ecological outcomes. More appropriate strategies work with natural diversity and river change.

and implementation of appropriate monitoring structure with the reference community), or de- procedures are integral in gauging the success of creases in indicators of degradation (e.g., active these strategies. erosion, salinity extent or impact, nonnative plant The process of river rehabilitation is a learning cover). The choice of parameters to be monitored experience that requires ongoing and effective must go hand in hand with the setting of goals, en- monitoring in order to evaluate and respond to suring that they are relevant to the type of river findings. Measuring success must include the pos- under consideration, so that changes in condition sibility of measuring failure, enabling midcourse can be meaningfully captured. Baseline data are re- corrections, or even complete changes in direction quired to evaluate changes induced by the project, (Hobbs, 2003). If effectively documented, each including a detailed historical study (Downs and project can be considered as an experiment, so that Kondolf, 2002). Monitoring should be applied over failure can be just as valuable to science as success, an extensive period, at least a decade, with surveys provided lessons are learnt. Goals or performance conducted after each flood above a predetermined targets must be related to ecological outcomes and threshold (Kondolf and Micheli, 1995). These vari- be measurable in terms such as increases in health ous components are integral parts of effective river indicators (e.g., increasing similarity of species or rehabilitation practice. Introduction 11

1.6 Overview of the River Styles framework

Best practice in natural resources management re- quires appropriate understanding of the resource that is being managed, and effective use of the best available information. In river management terms, catchment-scale information on the char- acter, behavior, distribution, and condition of different river types is required if management strategies are to “work with nature.” Given that rivers demonstrate remarkably different charac- ter, behavior, and evolutionary traits, both between- and within-catchments, individual catchments need to be managed in a flexible man- Figure 1.5 Routes to description, explanation, and ner, recognizing what forms and processes occur prediction where, why, how often, and how these processes have changed over time. The key challenge is to understand why rivers are the way they are, how they have changed, and how they are likely to look scale patterns and rates of biophysical fluxes. and behave in the future. Such insights are funda- Separate layers of information are derived to ap- mental to our efforts at rehabilitation, guiding praise river character and behavior, geomorphic what can be achieved and the best way to get there. condition, and recovery. Definition of ongoing ad- This book presents a coherent set of procedural justments around a characteristic state(s) enables guidelines, termed the River Styles framework, differentiation of the behavioral regime of a given with which to document the geomorphic struc- river type from river change. Analysis of system ture and function of rivers, and appraise patterns of evolution is undertaken to appraise geomorphic river types and their biophysical linkages in a river condition in context of “expected attributes” catchment context. Meaningful and effective de- of river character and behavior given the reach set- scription of river character and behavior are tied to ting. Interpretation of catchment-specific linkages explanation of controls on why rivers are the way of biophysical processes provides a basis with they are, how they have evolved, and the causes of which to assess likely future patterns of adjust- change. These insights are used to predict likely ment and the geomorphic recovery potential of river futures, framed in terms of the contemporary each reach. The capacity, type, and rate of recovery condition, evolution, and recovery potential of any response of any given type of river are dependent given reach, and understanding of its trajectory of on the nature and extent of disturbance, the inher- change (Figure 1.5). ent sensitivity of the river type, and the operation The River Styles framework is a rigorous yet of biophysical fluxes (both now and into the future) flexible scheme with which to structure observa- at any given point in the landscape. When these no- tions and interpretations of geomorphic forms and tions are combined with interpretations of limit- processes. A structured basis of enquiry is applied ing factors to recovery and appraisal of ongoing and to develop a catchment-wide package of physical likely future pressures that will shape river forms information with which to frame management ac- and processes, a basis is provided to assess likely tivities (Figure 1.6). This package guides insights future river condition, identify sensitive reaches into the type of river character and behavior that is and associated off-site impacts, and determine the expected for any given field setting and the type of degree/rate of propagating impacts throughout a adjustments that may be experienced by that type catchment. of river. A catchment-framed nested hierarchical The strategy outlined in this book emphasizes arrangement is used to analyze landscapes in the need to understand individual systems, their terms of their constituent parts. Reach-scale forms idiosyncrasies of forms and processes, and evolu- and processes are viewed in context of catchment- tionary traits and biophysical linkages, as a basis to 12 Chapter 1

fl

fl

fl

Figure 1.6 Stages of the River Styles framework

determine options for management – in planning, selection of the most appropriate technique. policy, and design terms. System configuration Rather, emphasis is placed on the need to appraise and history ensure that each catchment is unique. each field situation separately, viewed within its In making inferences from system-specific infor- catchment context and evolutionary history. The mation, cross-reference is made to theoretical and underlying catchcry in applications of the River empirical relationships to explain system behav- Styles framework is “KNOW YOUR CATCH- ior and predict likely future conditions. Principles MENT.” outlined in this book provide a conceptual tool with which to read and interpret landscapes, rather than a quantitative approach to analysis of river 1.7 Layout and structure of the book forms and processes. Application of these proce- dures provides the groundwork for more detailed This book comprises four parts (Figure 1.7). Part A site- or reach-specific investigations. outlines the geoecological basis for river manage- However, application of geomorphic principles ment. Chapter 2 documents the use of geomor- in the determination of sustainable river manage- phology as a physical template for integrating ment practices is far from a simple task. The need biophysical processes, working with linkages of for system-specific knowledge and appropriate biophysical processes within a catchment frame- skills with which to interpret river evolution and work, and the need to respect diversity (work with the changing nature of biophysical linkages (and nature). Chapter 3 outlines how geomorphic prin- their consequences) ensure that such exercises ciples provide a basis for river management pro- cannot be meaningfully undertaken using a pre- grams to work with change through understanding scriptive cook-book approach. The cautious, data of controls on river character and behavior and pre- intensive measures applied in this book are con- diction of likely future adjustments. sidered to present a far better perspective than Geomorphic principles that underpin applica- managing rivers to some norm! Hopefully, lessons tions of the River Styles framework are document- have been learnt from the homogenization of river ed in Part B. Pertinent literature is reviewed to courses under former management regimes. assess river character (Chapter 4), interpret river Management applications of the River Styles behavior (Chapter 5), analyze river evolution and framework focus on the derivation of a catchment- change (Chapter 6), and appraise river responses to scale vision for conservation and rehabilitation, human disturbance (Chapter 7). identification of reach-specific target conditions The River Styles framework is presented in Part that fit into the bigger-picture vision, and applica- C. An overview of the framework in Chapter 8 is tion of a geomorphologically based prioritization followed by a brief summary of practical and logis- procedure which outlines the sequencing of ac- tical issues that should be resolved prior to its tions that best underpins the likelihood of man- application. Chapter 9 presents the step-by-step agement success. The framework does not provide procedure used to classify and interpret river char- direct guidance into river rehabilitation design and acter and behavior in Stage One of the framework. Introduction 13

Figure 1.7 Structure of the book 14 Chapter 1

Procedures used to assess geomorphic condition of identify target conditions for river rehabilitation, rivers in Stage Two of the framework are presented and prioritize where conservation and rehabilita- in Chapter 10. Evolutionary insights are used to in- tion should take place. terpret the future trajectory and recovery potential The concluding chapter, in Part D, outlines an of rivers in Stage Three of the framework (Chapter optimistic (aspirational) perspective on future 11). Finally, Chapter 12 outlines Stage Four of the river management practices and outcomes River Styles framework, which can be used to de- (Chapter 13). velop catchment-framed visions for management, PART A

The geoecological basis of river management

(A)n understanding of the nature of the building blocks that compose a particular landscape is fundamental to understanding how geomorphological processes function as ecological disturbance processes at the watershed or landscape scale. Dave Montgomery, 2001, p. 249

Overview of Part A strategies should strive to maintain unique or dis- tinctive attributes of river courses. This part demonstrates how principles from Chapter 3 outlines how theoretical and field- fluvial geomorphology can be used to develop an based insights must be combined to meaningfully ecosystem approach to river analysis and manage- describe and explain river systems. These insights ment. In Chapter 2, spatial considerations in geo- provide a critical platform for our efforts at predic- morphology and management practice are framed tion. Themes discussed in this chapter include in terms of a nested hierarchical approach to catch- the need for management programs to work with ment characterization. Principles from fluvial geo- change, moving beyond notions of equilibrium morphology are shown to provide an integrative and stability used in engineering applications. physical template with which to assess habitat as- Timeframes of river adjustment, assessment of sociations and linkages of biophysical processes in controls on river character and behavior, and ap- landscapes. Finally, the concept of respecting di- proaches to prediction are also outlined. versity is introduced, indicating why management