Application of the River Styles framework as a basis for ... - CiteSeerX

Applied Geography 22 (2002) 91–122 www.elsevier.com/locate/apgeog

Application of the River Styles framework as a basis for river management in New South Wales, Australia G. Brierley a,∗, K. Fryirs a, D. Outhet b, C. Massey c a Department of Physical Geography, Macquarie University, North Ryde, NSW 2109, Australia New South Wales Department of Land and Water Conservation, PO Box 3720, Parramatta, NSW 2124, Australia c New South Wales Department of Land and Water Conservation, PO Box 118, Bega, NSW 2550, Australia

b

Received 1 February 2001; received in revised form 15 June 2001; accepted 3 July 2001

Abstract If strategies in natural resource management are to ‘work with nature’, reliable biophysical baseline data on ecosystem structure and function are required. The River Styles framework provides a geomorphic template upon which spatial and temporal linkages of biophysical processes are assessed within a catchment context. River Styles record river character and behaviour. As the capacity for a river reach to adjust varies for each style, so too do management issues and associated rehabilitation programmes. The framework also provides a basis for assessing geomorphic river condition and recovery potential, framed in terms of the evolutionary pathways of differing River Styles in the period since the European settlement of Australia. Within a catchment context, the River Styles framework provides a unified baseline upon which an array of additional information can be applied, thereby providing a consistent framework for management decision-making. The framework was developed as a research tool by geomorphologists working in collaboration with the New South Wales Department of Land and Water Conservation, which has used it for a range of river management applications. Target conditions for rehabilitation programmes are framed within a catchment vision that integrates understanding of the character, behaviour, condition and recovery potential of each reach. A prioritization procedure determines the most cost-effective and efficient strategies that should be implemented to work towards the catchment vision. In addition, the River Styles framework is being used to identify rare or unusual geomorphic features that should be pre-

∗

Corresponding author. Tel.: +61-2-9850-8427; fax: +61-2-9850-8420. E-mail address: [email protected] (G. Brierley).

0143-6228/02/$ - see front matter  2002 Published by Elsevier Science Ltd. PII: S 0 1 4 3 - 6 2 2 8 ( 0 1 ) 0 0 0 1 6 - 9

92

G. Brierley et al. / Applied Geography 22 (2002) 91–122

served, assess riparian vegetation patterns and habitat availability along river courses, and derive water licensing, environmental flow and water quality policies that are relevant to river needs in each valley. Based on these principles, representative biomonitoring, benchmarking and auditing procedures are being developed to evaluate river health.  2002 Published by Elsevier Science Ltd. Keywords: Australia; Fluvial geomorphology; River management; River rehabilitation; River styles

Introduction The theory and practice of environmental management in Australia have been subjected to major changes in the past decade or so, with increasing emphasis on stakeholder and community initiatives in natural resources management (Conacher & Conacher, 2000). Many researchers now work directly with managers to bring about changes in environmental practice. Geographers are ideally placed to work at the interface between scientific understanding of biophysical processes and direct management applications, through the provision of tools and techniques for catchment planning and on-the-ground applications in conservation and rehabilitation programmes (Brookes & Shields, 1996; Downs & Thorne, 1996; Rutherfurd, Jerie, Walker, & Marsh, 2000). In this study, collaboration between researchers at Macquarie University and the New South Wales Department of Land and Water Conservation (NSW DLWC) is documented, showing how this collaboration has changed the focus of river management practices in New South Wales, particularly in the Bega catchment, on the south coast. Over the last decade or so principles from fluvial geomorphology have been embraced as a core component of river management practices in Australia and overseas (e.g. Newson, 1992; Sear, 1994; Downs, 1995a; Kondolf, 1995a; Sear, Newson & Brookes, 1995; Newson, Clark, Sear, & Brookes, 1998; Brierley, 1999; Rutherfurd, Jerie, Walker, & Marsh, 1999). Geomorphology provides an ideal starting point for evaluating the interaction of biophysical processes within a catchment, as geomorphological processes determine the structure, or physical template, of a river system. Understanding of geomorphic processes, and determination of appropriate river structure and function at differing positions in catchments, are critical components in sustainable rehabilitation of aquatic ecosystems (Southwood, 1977; Poff & Ward, 1990; Newson, 1992; Brookes, 1995; Imhof, Fitzgibbon, & Annable, 1996; Maddock, 1999). The geomorphic structure and function of many rivers are tied innately to vegetation cover and composition, and the loading of large woody debris (e.g. Hickin, 1984; Brooks, 1999a; Millar, 2000). These interactions induce direct controls on the distribution of flow energy, dictating local-scale patterns of erosion and deposition at differing flow stages. When tied to sediment availability and flow variability, geomorphic structure dictates the diversity of hydraulic units and associated habitats along river courses, and many other facets of aquatic ecosystem functioning (e.g. nutrient flow, transfer of organic materials, etc.; see Taylor, Thomson, Fryirs, & Brierley, 2000). Based on these considerations, river morphology and


93

vegetation associations must be appropriately reconstructed before sympathetic rehabilitation of riverine ecology will occur. Two examples of differing patterns of interactions of biophysical processes related to the geomorphic structure of rivers are presented in Fig. 1. Most Australian rivers are now part of highly modified landscapes in which human activities are dominant. Efforts at river rehabilitation cannot realistically aim to reconstruct landscapes of the period prior to European settlement. The catchment conditions under which many rivers now operate (in terms of water and sediment transfer and vegetation coverage) have been fundamentally altered, in many cases irreversibly. As many river systems are now adjusting to a new set of boundary conditions (Cairns, 1989), management programmes must strive to adopt river rehabilitation strategies that work with the contemporary catchment conditions. As rivers demonstrate remarkably different characters, behaviours and evolutionary traits (both between and within catchments), individual catchments need to be managed in a flexible manner, recognizing what forms and processes occur where, why and how often, and how these processes have changed over time. To achieve this, a physical template is required upon which to assimilate and order information, identify gaps and, most importantly, highlight linkages of biophysical processes and their management implications. Without this template, management programmes are applied in an ad hoc manner. It is not unduly cynical to ask how management strategies can work within a sustainable framework if the principles adopted do not ‘work with nature’, building on a catchment-framed understanding of river character and behaviour. Unfortunately, at the beginning of the 21st century there remains a serious lack of baseline information on the character, behaviour and distribution of different river types across the Australian continent. The River Styles framework provides a geomorphic tool for catchment-wide assessment of river character, behaviour, evolution and condition (Brierley & Fryirs, 2000; Fryirs & Brierley, 2001). The framework was developed by Gary Brierley, Kirstie Fryirs and colleagues in the Department of Physical Geography at Macquarie University, working in direct collaboration with river managers and applied geomorphologists in the NSW DLWC, with support from Land and Water Australia (LWA). To date, the framework has been applied to 14 New South Wales coastal catchments. NSW DLWC staff are now applying it across many other catchments in the state to meet the requests of stakeholder committees and boards. A statewide GIS database will be established so that the information can be readily accessed by anyone interested in river management activities. A River Style is a river reach with a near-uniform assemblage of geomorphic units (Brierley & Fryirs, 2000). Stage 1 of the River Styles framework entails the identification, interpretation and mapping of River Styles throughout a catchment (Brierley & Fryirs, 2000) to provide a baseline survey of river character and behaviour. The second stage assesses the geomorphic condition of each reach of each style in the catchment, framed in terms of an analysis of river evolution. By placing each reach in its catchment context, its geomorphic recovery potential is determined in stage 3 (see Fryirs & Brierley, 2000). From this, predictions of likely future river condition are determined. With this information in hand, realistic target conditions

94



95

Fig. 1. Geomorphology as a physical template. Note: Principles from fluvial geomorphology can be applied to derive a template with which to explain the interaction of various biophysical processes along river courses, including vegetation type, hydraulic diversity and habitat availability. In Example A, the geomorphic structure of an intact valley fill comprises a relatively flat and featureless swamp, with a discontinuous channel and localized ponding. The moisture gradient across the swamp results in different vegetation associations, with Melaleuca sp. at the margins and Juncus sp. in the centre (Inset B). All flood events inundate the swamp surface and filter through the organic-rich sediments, thereby maintaining base flows to downstream reaches. One of the most frequently occurring river types in coastal catchments of New South Wales comprises pockets of floodplain within partly confined valleys (Example B). An array of geomorphic units is evident, including primary, backwater and chute channels, a dissected bar platform, and floodplain pockets (Inset A). As noted in Inset B, differing geomorphic surfaces have distinct substrates, inundation frequencies and associated magnitude–frequency relationships. This results in the prominence of primary colonising species on bar surfaces, open forest associations on the floodplain, and swamp associations in valley marginal back channels.

for river rehabilitation programmes are identified for each reach in stage 4, framed within a catchment-based vision. Working with local/regional catchment managers, a physically based procedure to prioritize management strategies for river rehabilitation and conservation is then applied. The identification and characterization of a River Style is not simply a visual assessment of a river, but a summary understanding of how that river operates or behaves within its valley setting. The geomorphic unit framework (Brierley, 1996) provides the fundamental interpretative tool that sets the River Styles framework apart from other ‘classification’ schemes. These building blocks of rivers record the form-process associations occurring along a reach. The River Styles framework endeavours to move beyond visual and mechanical approaches to river classification to provide a more process-based procedure for analysing river character and behaviour (cf. Mosley, 1987; Church, 1992; Rosgen, 1994, 1996; Montgomery & Buffington, 1997; Raven, Fox, Everand, Holmes, & Dawson, 1997; Newson et al., 1998; Rowntree & Wadeson, 1999). Prescriptive and regionally specific river classification procedures provide little sense of river process, river change, river condition or trajectory (Kondolf, 1995a; Kondolf & Downs, 1996; Miller & Ritter, 1996). Unlike these schemes, the River Styles framework is: 앫 Open-ended and generic. New variants can be added as the framework is applied in new environmental settings. It is not a rigid scheme that ‘pigeonholes’ rivers into categories. 앫 Process-based. Understanding of the character and behaviour of both channel and floodplain zones provides the process-based knowledge to manage rivers in a way that ‘works with nature’. 앫 Catchment-based. Linkages of biophysical processes in catchments, such as water and sediment fluxes and vegetation dispersal, can be analysed. 앫 Structured hierarchically. Processes occurring at finer scales can be explained by those occurring at higher levels in the hierarchy (see Brierley & Fryirs, 2000, and references therein). 앫 Set within the context of river evolution. Understanding a river’s capacity to adjust

96


Fig. 2. Procedures used to identify River Styles. Note: The degree of valley confinement along a reach is the first step in the identification of River Styles. Three classes are differentiated: confined, partly confined and alluvial valley settings. Different procedures are used to identify River Styles for each of these classes. In confined valley settings, the abundance of floodplain pockets forms the first level of analysis, followed by bed material texture and the make-up of geomorphic units on the valley floor (cf. Grant, Swanson, & Wolman, 1990; Montgomery & Buffington, 1997). In partly confined valley settings, the extent and role of bedrock control on the distribution of floodplain pockets is the key determinant in the differentiation of bedrock- and planform-controlled River Styles. Bed material texture and geomorphic units determine finer levels of analysis. Differentiation of alluvial River Styles is based initially on the presence and continuity of the channel. For absent or discontinuous channels the valley floor texture and array of geomorphic units are key considerations. For alluvial rivers with continuous channels, conventional planform-based notions are followed in the identification of River Styles (cf. Rust, 1978), with additional layers reflecting bed material texture (cf. Schumm, 1977) and the assemblage of geomorphic units along the reach (cf. Brierley, 1996).

within its valley setting provides the basis for assessing how far from its ‘natural’ condition the river sits, and why that type of river has changed. Only then can the contemporary condition of a river be realistically assessed. 앫 Directly linked to assessment of the trajectory of future river condition (recovery potential). Analysis of river change provides a basis to predict how a river will adjust in the future. This provides a geomorphic basis for determining future target conditions for river rehabilitation and creating a catchment-framed vision. In the River Styles framework, differentiation of river character and behaviour is initially based on the valley setting of a river, using procedures outlined in Fig. 2. Using this procedure, 21 River Styles have been identified in coastal valleys of New South Wales. The critical geomorphic units that comprise each style are indicated

Fig. 3. Procedures used to name River Styles in coastal catchments of New South Wales. Note: Following procedures outlined in Fig. 2, 21 River Styles have been identified in coastal valleys of New South Wales (noted in italics). Three are in confined valley settings, three in partly confined valley settings, four in alluvial (discontinuous channel) valley settings, and eleven in alluvial (continuous channel) valley settings. Differentiation of River Styles is based, in part, on the scale of analysis of reaches. In this instance, identification has been made for reaches of several kilometres length.

G. Brierley et al. / Applied Geography 22 (2002) 91–122 97

98



99

Fig. 4. Schematic planform views of River Styles in coastal catchments of New South Wales. Note: Each River Style has a characteristic planform and geomorphic unit assemblage. River Styles in confined valley settings have no floodplain or occasional floodplain pockets. The shape of the valley (sinuous, irregular or straight) dictates the position of discontinuous floodplain pockets and the alignment of the channel within the partly confined valley setting. Discontinuous alluvial channels have a number of forms, ranging from ponds through discontinuous channels to featureless swamps. Alluvial valley settings with continuous channels are characterized by continuous floodplains along both channel margins. These rivers display an array of forms largely dependent on channel slope and the texture of the channel banks and bed. Geomorphic unit assemblages range markedly from style to style. As the River Styles framework is open-ended, new variants or river can be identified, such as the multi-channel sand belt.

on Fig. 3, and schematic planform representations are presented in Fig. 4. Given the open-ended nature of the procedure, the range of River Styles is not prescriptive and can be added to as new variants arise. For example, although no braided rivers are evident in coastal valleys of New South Wales, sand or gravel braided rivers could easily be added to the procedural trees shown in Figs 2 and 3. The explanatory and predictive bases of the River Styles framework provide a rigorous physical basis for management decision-making. The key management applications and implications outlined in this manuscript are as follows.

1. The River Styles framework is used to determine management programmes that ‘work with nature’. 2. Rare or unique River Styles are identified, such that appropriate conservation measures can be developed and applied. 3. Linkages of biophysical processes within a catchment are integrated into river management plans. 4. Geomorphic condition and river recovery potential are assessed. 5. A catchment-based physical vision is derived. 6. Realistic target conditions are identified for each reach in the catchment. 7. A catchment-based prioritization framework for river management programmes is developed. 8. Representative reaches are selected for various biomonitoring programmes used to audit the impacts of environmental flows, water licensing and water quality.

This paper demonstrates the application of the River Styles framework in several on-going management programmes carried out by NSW DLWC. Particular emphasis is placed on Bega catchment, on the south coast of New South Wales, where detailed geomorphic research has been undertaken (Brooks & Brierley, 1997, 2000; Brierley & Fryirs, 1998, 1999; Fryirs & Brierley, 1998, 1999, 2001; Brierley, Cohen, Fryirs, & Brooks, 1999a).

100


Applications of the River Styles framework Using River Styles to develop management programmes that work with nature All too often rivers have been managed to some norm, with undue emphasis placed on their stability. In the River Styles framework, management programmes are derived to ‘work with’ the contemporary character and behaviour of rivers, recognizing the diversity of patterns and rates of adjustment. Interpretation of form-process associations for the assemblage of geomorphic units that make up a River Style Table 1 The capacity for adjustment of various examples of River Styles and typical associated management response River Style Confined valley setting Gorge

Capacity for adjustment

Management response

앫 Minimal 앫 Bed material organization can locally adjust

앫 Preserve and protect

Partly confined valley setting Bedrock- controlled 앫 Local channel expansion discontinuous 앫 Floodplain stripping floodplain Alluvial valley setting discontinuous channel Floodout 앫 Shifting loads of sediment accumulation as feeder channel(s) shift Chain-of-ponds

앫 Pond expansion and deepening

Alluvial valley setting - continuous channel Meandering fine 앫 Bed incision grained 앫 Channel expansion 앫 Channel abandonment Meandering gravel bed

앫 앫 앫 앫

Channel migration Bed incision Channel expansion Floodplain stripping

앫 Woody debris placement 앫 Fencing and revegetation 앫 Ensure compatible land use

앫 Ensure compatible land use on the active shallow-angle fan 앫 Proactive nickpoint control 앫 Fencing and revegetation 앫 Ensure compatible land use 앫 Proactive nickpoint control

앫 Bed control 앫 Fencing and revegetation 앫 Ensure compatible land use 앫 앫 앫 앫 앫

Bed control Bank protection Woody debris placement Fencing and revegetation Ensure compatible land use


101

provides insight into the capacity for river adjustment in a reach. Different management problems tend to arise in differing types of river. As a consequence, different river rehabilitation techniques must be applied, as effective management responses aim to fix underlying causes rather than the symptoms of change. Examples of differing patterns of river adjustment, and typical management responses as applied by NSW DLWC, are summarized in Table 1. Certain types and rates of geomorphic change fall within the natural range of behaviour for any River Style. The degree of inherent stability varies naturally from style to style, from reach to reach, and from subcatchment to subcatchment. Accordingly, some stream systems are more sensitive to physical and biological disturbance than others. Hence, identification of River Styles guides what types of problems are to be expected where, and what natural patterns and rates of adjustment are expected for different types of streams. The key is to determine the capacity for adjustment for each style by interpreting the potential ways in which a river can adjust within its valley setting (cf. Downs, 1995b). For example, the natural proportion of eroding banks varies markedly from one River Style to another. In a chain-of-ponds style, bank erosion is unexpected, but in an alluvial meandering style, natural patterns of bend migration may result in active erosion along up to 50% of banks. In some settings, channel avulsion is a ‘natural’ component of the river’s long-term behavioural regime. For example, wandering gravel-bed rivers ‘naturally’ switch channels at differing flow stages. Therefore, trying to maintain stability (no change) is not a sustainable basis for rehabilitating such streams. It is now recognized that reducing rates of change that have been accelerated by disturbance in the period since European settlement is the only practical solution to river rehabilitation in many instances. Most reaches that are sensitive to adjustment are found in alluvial valley settings, where the river has the capacity to adjust its form. The removal of riparian vegetation and large woody debris along many alluvial reaches of rivers in coastal New South Wales in the period since European settlement has brought about profound changes to river morphology (Abernethy & Rutherfurd, 1998; Brooks, 1999b). Positive feedback mechanisms induced by increased channel capacity have increased sediment transport capacity and stream power conditions to such a degree that changes to river character and behaviour are to all intents and purposes irreversible. However, over 70% of river courses mapped in New South Wales coastal catchments comprise confined or partly confined valley settings (Brierley et al., 1999b). In the latter settings, processes such as catastrophic stripping are promoted as high stream powers are generated and flow energy is concentrated across the valley floor (cf. Nanson, 1986). While the capacity for these streams to strip their floodplains under a fully vegetated cover is conjectural, contemporary river management programmes must recognize the potential for profound adjustments to river morphology in these reaches. It is only in the light of understanding of the natural range of character and behaviour of differing river reaches, framed in terms of a river’s capacity for adjustment, that management strategies can be devised that ‘work with nature’.

102


Conservation of unique or rare River Styles Identification of unique or rare reaches of a River Style provides a basis upon which to conserve these rivers to maintain the geodiversity of fluvial landscapes (cf. Boon, 1992; Naiman, Lonzarich, Beechie & Ralph, 1992; Newson, 1992; Downs & Gregory, 1994; Penn, 1999; Rutherfurd et al., 1999, 2000). This has implications for conservation programmes at local, catchment, regional or even state/national levels (Koehn, Brierley, Cant, & Lucas, 2001). River Styles assessments undertaken in coastal New South Wales have identified river variants not previously described in the geomorphology literature. For example, in the Richmond catchment, discontinuous sand-bed and multi-channel sand-belt River Styles were identified in the sandstone landscape in the south of the catchment (Goldrick, Brierley, & Fryirs, 1999). As another example, the wandering gravel-bed and low sinuosity boulder-bed River Styles are only found (so far) in isolated sections of the Bellinger, Hastings, Macleay and Tweed catchments on the north coast. Similarly, the distribution of intact valleyfill and chain-of-ponds styles has highlighted the limited range over which these once prevalent river types extend. These two styles maintain base flow and filtering processes throughout catchments, providing unique habitats for aquatic fauna (see Fig. 1a). Identification of these rare or unique reaches has only been achieved through catchment-wide baseline surveys of river character and behaviour. Sadly, such baseline data are still missing across much of the Australian continent. Implications of catchment-framed biophysical linkages in river management plans In proactive river rehabilitation programmes, upstream-downstream and tributarytrunk stream linkages of biophysical processes are a fundamental component in the design of reach-based plans (cf. Downs & Brookes, 1994; Brookes, 1995; Kondolf & Downs, 1996; Brookes & Sear, 1996; Sear, 1996; Fryirs & Brierley, 2001). Issues such as sediment movement, water transfer and seed dispersion are critical factors in determining what can realistically be achieved in each reach. In the River Styles framework, assessment of upstream-downstream linkages places each reach within its catchment context, enabling off-site impacts to be interpreted. For example, if a nickpoint is excavating a valley fill, the potential exists for extensive sediment removal. Impacts will vary, depending on the downstream River Style. While sediments may be flushed through confined or partly confined valley settings, with impacts restricted to local bed aggradation and transitory infilling of pools, there may be much more profound impacts if the sediment slug reaches an alluvial River Style, where the capacity for river adjustment may be significant (e.g. lateral channel expansion, sedimentation on floodplains, increased homogeneity of the channel bed, etc.). Alternatively, if upstream sediment availability is limited, the potential for geomorphic river recovery in over-enlarged channels downstream is limited (cf. Kemp, Harper & Crossa, 1999; Fryirs & Brierley, 2001). In the River Styles framework these issues are addressed by analysing the downstream pattern of River Styles. The example presented in Fig. 5 shows how downstream patterns of flow and sediment transfer vary along river courses in two adjacent subcatchments in Bega catchment.


103

Fig. 5. River Styles in Wolumla catchment, South Coast, New South Wales. Note: Six River Styles have been identified in Wolumla catchment, which drains an area of around 130 km2 of granitic terrain in the southern part of Bega catchment on the New South Wales south coast (Brierley & Fryirs, 2000). Along Wolumla Creek four River Styles occur. In the headwaters, which drain from the escarpment zone, the Gorge River Style (A) is characterized by bedrock steps and waterfalls, separated by rapids and bedrockinduced pools. Gradients are steep and no floodplain occurs along the valley margin. Immediately downstream of the escarpment, the valley widens and an alluvial channelized fill River Style (B) develops. This is characterized by continuous valley flats along both sides of an incised trench. The floor of the trench comprises a series of inset features, sand bars, sand sheets and swampy low-flow channels. Prior to European settlement, this reach contained an intact valley fill River Style (River Style E along Frogs Hollow Creek). Further downstream, a partly confined valley with bedrock controlled discontinuous River Style (C) occurs. The channel abuts the valley margin along 10–90% of the sinuous valley. Discontinuous pockets of floodplain occur between bedrock spurs or on the insides of bends. The channel is characterized by point bars, point benches, inset features and sand sheets. At the lower end of Wolumla Creek the valley narrows considerably, and a confined valley with occasional floodplain pockets River Style (D) occurs. This is characterized by occasional shallow, narrow pockets of floodplain. The channel abuts the valley margin along 90% of its length. Significant bedrock outcrops induce an irregular series of pools, islands, runs and sand bars. Frogs Hollow Creek, to the east, is a discontinuous watercourse. The intact valley fill River Style (E) at the base of the escarpment is one of the last remnants of a pre-European swamp in Bega catchment (see Fig. 1A). This swamp is threatened by a nickpoint that forms the upper boundary of the confined valley with occasional floodplain pockets River Style (F) immediately downstream. In the middle section of Frogs Hollow catchment, the last remaining floodout River Style (G) in Bega catchment occurs. This reach is characterized by an intact swamp surface over which sands are splayed at the mouth of a discontinuous channel. As noted along lower Wolumla Creek, lower Frogs Hollow Creek comprises a confined valley with occasional floodplain pockets River Style (H). The differing patterns of River Styles along Wolumla and Frogs Hollow Creeks result in differing connectivity of biophysical processes along these river courses. Water, sand and nutrients are readily flushed along Wolumla Creek, with peaked flood flows. In contrast, retention of base flows, fine grained sediment and nutrients is much more significant along the discontinuous channels of Frogs Hollow Creek. These conditions result in the maintenance of remnant habitat niches along swamp zones.

104


Assessment of geomorphic condition and river recovery potential Effective river management plans must work with the character and behaviour of each reach, the linkage of biophysical processes that determine the present and likely future behaviour of the reach, and associated assessments of river condition and recovery potential. Although significant research has focused on ecological condition and recovery potential components (e.g. Gore, 1985; Gore, Kelly, & Young, 1990; Milner, 1994; Bradshaw, 1996; Hobbs, 1997), few procedures are available for evaluating these components in geomorphic terms (cf. Sear, 1994; Brookes, 1995; Brookes & Sear, 1996). Those tools that are available need to be expressed in terms of practical guidelines for assessing river condition and recovery potential. This oversight has been addressed in the River Styles framework (Fryirs & Brierley, 2000). Any assessment of river condition must be framed relative to some benchmark or reference point (Cairns, 1989; Kondolf & Downs, 1996). However, simple analysis of changes to river forms and processes does not provide a direct measure of geomorphic river condition. In the River Styles framework, geomorphic condition is assessed relative to the natural range of variability that is considered to be appropriate for the River Style and the reach setting, given the present-day controls. Studies of river evolution are used to assess the nature, extent and rate of changes imposed since European settlement (cf. Kondolf & Larson, 1995). This provides an indication of how far from a ‘good’ or ‘natural’ geomorphic structure and function differing reaches of river are. Reaches that have fully adjusted to contemporary controls, are self-maintaining, and are operating within their natural range of variability are put in the ‘good’ category. Reaches that are still recovering and/or have accelerated rates of change are put in the ‘moderate’ or ‘poor’ categories, depending on the degree of degradation. Assessment of river condition, in itself, provides an insufficient physical platform from which to rehabilitate rivers. Effective management strategies that ‘work with nature’ must appreciate the trajectory of change. Extensive geomorphic research on river evolution, magnitude-frequency relations, and notions such as complex response, have highlighted how recovery processes, and their geomorphic consequences, are not necessarily the reverse of geomorphic responses to degradational influences (e.g. Schumm, 1973; Simon, 1989; Hupp, 1992; Renwick, 1992; Fryirs & Brierley, 2000). The critical question here is: if the river were to be left alone, would its condition deteriorate or improve? Principles applied in the River Styles framework follow the lead from ecology, promoting enhanced geomorphic recovery of rivers as a basis for effective management programmes (see Kondolf, 1995a; Fryirs & Brierley, 2000). Limiting factors to geomorphic recovery are identified, such as sediment supply and transport capacity, the nature and variability of discharge (i.e. water transfer), vegetation distribution and character (including seed dispersion), the position of a reach within the catchment, the connectivity of processes throughout the catchment, and off-site impacts of degradation or disturbance in upstream or downstream reaches. Based on principles documented in Fryirs and Brierley (2000), an example of the application of the principles used to assess river condition and recovery potential in


105

Fig. 6. Application of the recovery potential framework for the partly confined valley with bedrockcontrolled discontinuous floodplain River Style. Note: In this figure a series of condition and potential recovery endpoints are identified for the partly confined valley with bedrock-controlled floodplain River Style in Bega catchment. Moving down the left-hand side of the figure, good, moderate and poor conditions of the style reflect changes that have occurred since European settlement. The extent of disturbance, and processes occurring in adjacent reaches (especially upstream), determine the likely pathway of adjustment of the reach (on the right-hand side of the figure). The reach can recover towards a restored condition whereby geomorphic structure and function is akin to an intact condition. Alternatively, if systematic or irreversible change has occurred to catchment boundary conditions, the reach will adjust towards a created condition. The recovery trajectory is used to designate appropriate target condition for management of the reach. Such a figure can be further broken down to provide short-to medium-term target conditions for river rehabilitation. The particular patterns of geomorphic adjustment and recovery, and associated identification of goals for river rehabilitation, are River Style specific.

106


the River Styles framework is shown in Fig. 6. There are two components to this figure. The vertical line on the left represents the continuum from an intact to a degraded condition. The contemporary character and behaviour of the reach can lie at any position along this degradation pathway, depending on the river’s sensitivity to disturbance, the character and degree of disturbance, and the time since disturbance. At any stage along this pathway, rivers are adjusting their character and behaviour to disturbance. If a natural system is resilient to disturbance, it oscillates in form around a mean condition and remains close to an intact condition (position A or B on Fig. 6). If disturbance is severe, such that a threshold condition is breached, the river cannot self-adjust, and falls along the degradation pathway (positions C, D or E). The right-hand side of Fig. 6 shows directions of river recovery following the cumulative impacts of disturbance. Two pathways are shown. In the first instance, the river system endeavours to return to a condition akin to its original or intact state (i.e. a restored river condition; position F). Alternatively, if catchment boundary conditions have been altered to such a degree that geomorphic changes to river structure are irreversible, the recovery pathway moves the river towards a new condition, termed river creation (position G). The transition to recovery, termed a turning point on Fig. 6, can occur at any stage along the sliding scale of the degradation pathway, as it is determined by a range of local, reach and off-site constraints. However, in general, the further down the degradation scale a reach sits, the less likely it is to regain a fully restored condition. Ultimately, the endpoint of recovery, whether restored or created, is attained when a reach achieves a structure and function that is self-maintaining under the conditions operating within the catchment. Since effective river rehabilitation strategies work with both the contemporary condition and trajectory of river changes, it is necessary to determine where each reach lies on the pathways indicated on Fig. 6. Given that each catchment includes a variety of River Styles at various stages of degradation and recovery, limiting factors to geomorphic recovery vary not only between catchments, but also between reaches. Placing the condition of a reach in the context of its within-catchment position, and producing an associated map of river recovery potential, provide a biophysical platform with which to derive a realistic catchment-framed vision for river management programmes. Creating a catchment-framed biophysical vision Most river rehabilitation projects in Australia, and elsewhere, have generally been applied in a piecemeal manner over relatively short reaches, without a sound understanding of the broader spatial and temporal context (e.g. Downs & Brookes, 1994; Brookes & Shields, 1996; Newson et al., 1998; Harper et al., 1999). Such reactive strategies are not the most efficient and cost-effective way to achieve rehabilitation success in ecological terms. Projects that fail to consider current trends in sediment delivery and the dominant fluvial processes in the reach are likely to require costly maintenance, or fail to achieve their intended goal (Sear et al., 1995; Sear, 1996).


107

All too often, however, this intended long-term goal is overlooked or poorly specified. Defining a catchment-framed ‘vision’ is a critical early step in effective river rehabilitation (Kondolf, 1995b). A vision statement envisages an improved state for a system that can be achieved at some stage in the future. The mission, goals and objectives of environmental projects fit into this over-arching vision. This provides a basis for assessing whether management efforts are successful. Bringing groups together to develop a shared vision generates the commitment and focus needed for a successful project (Rogers & Bestbier, 1997; Rutherfurd et al., 2000; Koehn et al., 2001). Application of the River Styles framework has been used to identify an achievable structure and function for river courses across a catchment, maximizing the potential to produce a self-adjusting (i.e. natural) river morphology that minimizes the need for invasive management techniques. Reach-scale goals can then be framed within a catchment-wide ‘vision’. This ‘vision’ of what is realistically achievable within a specified time-frame is derived from an understanding of the linkages between biophysical processes within the catchment, recognizing on-going and likely future ‘pressures’ that will be experienced, and prospective environmental changes (cf. Newson, 1994). From these insights, thresholds of probable concern and associated management responses can be identified (e.g. Mackenzie, van Coller, & Rogers, 1999). Adoption of these principles within NSW DLWC has resulted in coherent and proactive rehabilitation programmes that are spatially and temporally integrated (Table 2). The character and behaviour of individual River Styles, and their downstream pattern, provide an appropriate biophysical framework with which to develop river rehabilitation schemes that fit into the catchment-based vision. Due regard is given to potential off-site impacts, ensuring that balanced perspectives on sediment transfer are determined. For example, it may be pointless to expend significant effort and resource on ‘fixing’ a downstream reach if a large sediment slug sits immediately upstream, as the future geomorphological behaviour of the downstream reach will reflect river responses to the transfer and/or accumulation of those materials. Application of these principles is exemplified by the designation of a ‘vision’ for Wolumla catchment in Table 3. Extensive adjustments to river morphology have occurred here since European settlement (Brierley & Fryirs, 1998, 1999; Fryirs & Brierley, 1998, 1999). The catchment vision for management seeks to minimize rates of sediment loss from valley floors, improve riparian vegetation cover, and retain base-flow conditions for longer durations. In turn, this will lead to improved ecological associations along river courses. In general terms, strategies aim to minimize erosion and sedimentation problems by locking up sediment as appropriate. Wherever practicable, zones of instability (such as nickpoints) are prevented from extending further through the catchment. Riparian vegetation plans are tied to the geomorphic structure of the river, with parallel weed management programmes. Trapping of fine-grained materials enhances the retention of base flows, maximizing the potential for aquatic ecosystem functioning and improving water quality in receiving basins (cf. Zierholz, Prosser, Fogarty, & Rustomji, 2001). To achieve these biophysical goals, different reach-based strategies are required for the various River

P P P P P

P P P P P

F P P NA NA

P P X P P F NA NA

P P P P P F NA NA

P P P P X F P F

P X P P X P F P

P P P

P X P F P

P P P

P X P F F

P F P

F X F F F

X F X

Flow Water policy allocation and licensing

P = presently using, F = intend use in near future, NA = not applicable (e.g. no rehabilitation plans being done), X = not using River Styles for this purpose

P P P

P P P

North coast Hunter Sydney South Coast Barwon Central west Murrumbidgee Murray Far west

Identifying Funding Rehabilitation Rehabilitation Assessing River Monitoring rare or prioritization plans works capacity for health programmes unique rivers adjustment for conservation

Catchmentbased vision and planning

Region

Table 2 Use of River Styles within the regions of NSW DLWC (as of November 2000)

108 G. Brierley et al. / Applied Geography 22 (2002) 91–122


109

Table 3 A biophysical vision for Wolumla catchment Overall vision: Community and government working together, with nature, to improve the health of riverine ecosystems. What are we trying to achieve? The Wolumla Catchment Rivercare Plan has set priorities for onground works based on several criteria including: sediment and water storage and delivery issues, exotic weed eradication and planting of native vegetation, enhancing ecological recovery potential, cost effectiveness and ‘demonstration’ value. What are we managing for? The aim is to return the river system to a sustainable (self-maintaining) geomorphic and ecological condition, minimising the need for ongoing (reactive) maintenance. What do we want the river to be like? Healthier, catchment-wide river system with natural sediment regime, improved water quality, native vegetation and ecological associations. Issue

Long-term vision

Short-term action

Sediment regime

앫 Lock up sediment in cut-andfill River Styles at the base of the escarpment. 앫 Maintain balance between sediment input and output along mid-catchment reaches. 앫 Maintain remnant swamps and floodouts along Frogs Hollow Creek and lowerorder drainage lines that act as sediment sinks.

Upper catchment 앫 Protect remnant swamps and floodouts from nickpoint retreat. 앫 Cattle exclusion and fencing off. 앫 Revegetate riparian and withinchannel geomorphic surfaces to stabilise sediment stores. 앫 Bed control structures to retain sediment in within-channel swamps. Middle-lower catchment 앫 Riparian revegetation programmes to reduce rates of channel expansion, and removal of floodplain sediment. 앫 Bank control structures to aid sediment accumulation along the reach. 앫 Woody debris placement to stabilize in-channel sediments and induce pool development. 앫 Cattle access points to reduce bank and bed degradation.

Vegetation associations

앫 Remove willows and reestablish native vegetation associations along the river course. 앫 Reinstate a continuous riparian corridor.

앫 Willow control along river courses, with a commitment to sustained maintenance programmes. 앫 Replant native vegetation that suits the riparian environment for each River Style, using species that are indigenous to the region. Continued

110


Table 3 (Continued) Issue

Long-term vision

Short-term action

Water regime

앫 Maintain base-flow conditions and water storage in remnant swamps and floodouts for drought proofing and ecological refugia. 앫 Reduce time of travel and stream powers by flattening the hydrograph i.e. reduce flood peaks.

앫 Conserve and protect swamps and floodouts from nickpoint retreat. 앫 Undertake riparian and withinchannel revegetation programmes. 앫 Increase channel roughness through woody debris placement and revegetation of instream geomorphic surfaces.

Ecological associations

앫 Enhance native terrestrial and aquatic ecological associations. 앫 Reinstigate channel-floodplain connections (e.g. between channel habitat and floodplain wetlands). 앫 Improve water quality and organic matter retention. 앫 Maintain and improve the viability of remnant ecological niches in swamps and floodouts.

앫 Reduce channel capacities to reinstigate channel-floodplain connectivity. This requires sediment storage and revegetation of geomorphic units at appropriate places along each River Style. 앫 Protect remnant swamps and floodouts. 앫 Supply and retain organic matter in the system through native revegetation programmes.

Styles along the primary streams, framing ‘target conditions’ within the broader catchment ‘vision’. Identification of reach-based target condition In the past, community groups and their technical advisers found the hardest part of the rehabilitation planning process to be determining the target condition for each reach of stream. As noted by Kondolf (1998), it is critical that rehabilitation programmes move beyond visual descriptions of river character (cf. Rosgen, 1994, 1996) and associated prescriptive, off-the-shelf management responses. Rather, reach-based processes and the implications of water and sediment delivery and vegetation issues must be understood in designating appropriate reach-based plans. Insights into recovery potential indicate how achievable the attainment of a ‘good’ condition for the reach is, including what actions need to be implemented to achieve this goal. The rehabilitation group then needs to match resources with actions to determine a practical target for the reach (Rutherfurd et al., 2000). In the River Styles framework, understanding of form-process associations in minimally impacted or fully adjusted reaches is used to guide the determination of


111

Table 4 Rivercare planning in Wolumla Catchment Background The Wolumla Landcare Group is currently implementing a Rivercare Plan to achieve the goals set out within the catchment-framed vision (see Table 3). NSW DLWC and the Far South Coast Landcare Association are providing technical advice and planning assistance. The first priority of the Rivercare Plan is to protect sediment sinks from incision and sediment removal (i.e. protecting intact valley fill and floodout River Styles). All potential sediment sources are targeted and stabilisation options are outlined. Broader ecological issues such as willow (Salix sp.) control and native vegetation replanting form part of the rehabilitation plan. Community participation One of the challenges of improving river/catchment health is educating people about geomorphic processes. This has been achieved through the use of the River Styles framework. In addition, communities need to be aware of methods of sustainable options for riparian and riverine management, and the necessity to undertake remedial works. To assist with this endeavour, a project has been partnered between the Wolumla Landcare Group, Commonwealth Government (NHT), NSW DLWC, Bega Valley Shire Council, Far South Coast Landcare Association and Land and Water Australia. The project involves rehabilitating three reaches in Wolumla Catchment (Fig. 7), applying a range of rehabilitation techniques. These reaches are: 1. Ticehurst - stabilize sediment stores along a 500-m reach of Wolumla Creek, in a partly confined valley with bedrock-controlled discontinuous floodplain River Style. 2. Sarjents Swamp - apply rehabilitation measures to minimize impacts from a nickpoint that is retreating into an intact tributary fill, in an area suffering from grazing pressure. 3. Frogs Hollow Swamp - protect an intact, high conservation priority remnant swamp from a retreating nickpoint. The sites are all in high-profile areas, close to major roads, and demonstrate several rehabilitation techniques that fit with the natural character and behaviour of the River Style. All sites have revegetation components as part of their respective recovery plans.

Project title/River Style

Description of remedial works

Total (material costs)

Ticehurst Partly-confined valley with bedrock-controlled discontinuous floodplain

앫 앫 앫 앫

$61 000 (completed)

Sarjents Swamp Intact valley fill

앫 bed-level cattle crossing 앫 log weir 앫 fencing and revegetation of swamp

$2 900 (completed)

Frogs Hollow Swamp Intact valley fill

앫 concrete flume (currently being designed) 앫 fencing and revegetation

$200 000 (planning stage)

150-m mesh fence and bays 150-m rock revetment wall rock flume on small nickpoint fencing and revegetation

Continued

112


Table 4 (Continued) Additional initiatives to achieve the catchment vision The Bega Valley Shire Council, NSW DLWC and Wolumla Landcare Group are implementing other sediment and vegetation management projects in the catchment. A timber, or mesh wire, bank protection structure will be constructed on Wolumla Creek within the bedrock-controlled discontinuous floodplain River Style. This structure will demonstrate the geomorphic function of large woody debris (LWD) in trapping river sediments and the role of vegetation in stabilizing that sediment. It will also complement works completed at the downstream Ticehurst site. The Landcare group have additional National Heritage Trust grants to target smaller, but strategically important, sediment sources. Greater appreciation of river processes and sustainable management practices has occurred within the Wolumla community through communication of findings from the River Styles and sediment budget studies, and the completion of the demonstration sites. In the year 2000, over 9000 locally grown trees and shrubs were planted on intact swamps, river banks and other sensitive areas in the catchment to reduce sediment removal and enhance the ecological integrity of the catchment.

appropriate river character, geomorphic unit assemblage, channel alignment, vegetation associations and sediment regimes for each River Style. Reference reaches used to define target conditions for each style should occupy a similar position in the catchment, with near-equivalent channel gradient, hydraulic and hydrological considerations (Kondolf & Downs, 1996). Generally, as stream order increases, a catchment offers fewer alternative reference reaches. As a result of this, and the widespread impact of developments in lowland areas, locating suitable reference reaches for higher-order rivers is problematic. Unfortunately, there are several River Styles in New South Wales for which natural, fully adjusted or minimally impacted reaches cannot be identified. For these styles, management programmes should aim to retain or improve geomorphic structure and hence the diversity of aquatic habitat through a long-term strategy of low-level intervention. Technical advisers in the NSW DLWC Rivercare programme and their client community groups are using River Styles maps and reports to locate reference reaches and determine stream rehabilitation techniques. An example from Wolumla catchment is outlined in Table 4. Although fluvial geomorphology has always been a consideration in Rivercare plans developed by NSW DLWC, the River Styles framework provides a template that integrates geomorphic and biologic information, ensuring that planners consistently take into account geomorphic behaviour and controls on that behaviour, within-catchment linkages of biophysical processes, and the evolutionary character and rate of change to river morphology. The River Styles framework now forms the basis for all geomorphic assessments undertaken on rivers by NSW DLWC. Community groups who apply rehabilitation programmes have commented on the usefulness of River Styles information and the consistent way it is presented and communicated. Prioritization of management efforts using the River Styles framework In developing catchment-wide river management programmes, critical decisions must be made on where in the catchment to start and the associated plan of activities.


113

Such decisions should be made using logical, testable and transparent procedures. While economic, cultural and social values place obvious constraints on how this is undertaken, a physical template forms a critical basis for decision-making. There has been significant independently based convergence of ideas in the development of strategic, proactive procedures for river conservation and rehabilitation programmes in Australia. For example, procedures outlined by Brierley (1999), Brierley and Fryirs (2000), Erskine and Webb (1999), Ladson and Tilleard (1998) and Rutherfurd et al. (1999) all view river rehabilitation as a process of recovery enhancement whereby management programmes strive to help the river to adjust naturally, reducing the need for on-going reactive management. Putting aside protection of infrastructure and equivalent site-specific requirements (e.g. rarity of a particular River Style), management emphasis in application of the River Styles framework is placed in the first instance on conservation of reaches that remain in good condition (see Brierley & Fryirs, 2000). The success of rehabilitation programmes is maximized by starting with reaches that have a high recovery potential, then working out into more degraded parts of the catchment. As recovery is already under way, a ‘do-nothing’ option may be quite feasible in reaches of high recovery potential. Elsewhere, minimally invasive approaches based on riparian vegetation management may facilitate accelerated recovery. Particular attention is given to strategic reaches or point-impacts where disturbances threaten the integrity of remnant or refuge reaches. An example is an actively retreating headcut (steep nickpoint). Without strategic actions in these reaches, the potential for degrading offsite impacts elsewhere (particularly in conservation reaches) is considerable. Irrespective of their geomorphic condition, these reaches must be targeted early in the river rehabilitation process. In degraded reaches that are experiencing sustained adjustment, inordinate expense on river rehabilitation programmes may not yield substantive outcomes, thus adversely impacting on community confidence in terms of river management efforts. Many of these reaches with low recovery potential are found along alluvial streams. The pre-disturbance character of such reaches cannot be regained, and concerted efforts would be required to improve geomorphic and ecological conditions. Management strategies must work with the prevailing boundary conditions to rehabilitate these river courses towards a sustainable structure and function that fits the catchment setting. Longer-term rehabilitation programmes, requiring invasive rehabilitation techniques, are expensive and have uncertain outcomes. Rather than spending significant dollars in trying to rehabilitate these streams, it may be more expedient to wait for these reaches to adjust to the prevailing environmental conditions before adopting intervention strategies. In general, the pattern of River Styles, their differing sensitivities to change, and the rarity of particular styles, have resulted in a fragmented distribution of conservation reaches across a catchment. In coastal catchments of New South Wales, however, most near-intact conservation reaches are restricted to headwater zones. Conversely, the lowland sections of many rivers are typically degraded, due to the concentration of impacts from upstream. However, these general trends mask pronounced variability, and conservation or rehabilitation priorities must be considered

114


Fig. 7. Application of the River Styles management prioritization procedure in the designation of river conservation and rehabilitation programs in Wolumla catchment. Note: In Wolumla catchment, conservation status was assigned to intact or rare reaches of River Styles that have appropriate geomorphic river structure and near-intact or remnant vegetation associations. These were noted in the gorge, intact valley fill and floodout River Styles. Strategic reaches were assigned to the areas immediately downstream of the intact valley fill and floodout River Styles, where nickpoints threaten the integrity of these reaches with potential loss of remnant ecological niches and release of over 1.5 million m3 of sediment (Fryirs & Brierley, 1999). Reaches with high recovery potential along the confined valley with occasional floodplain pockets River Style have little capacity for adjustment. The re-establishment of appropriate native vegetation associations and the maintenance of sediment throughput (which will excavate bedrock-induced pools) will produce a geomorphologically and ecologically self-maintaining river. The most degraded reaches in the catchment are located along the channelized fill and partly confined valley with bedrockcontrolled discontinuous floodplain River Styles along Wolumla Creek. These reaches have experienced significant geomorphic change in the period since European settlement (Brierley & Fryirs, 1998; Fryirs & Brierley, 1998). Vegetation is either non-existent or exotic in character. Large volumes of sediment have been released and significant erosion still occurs. These reaches will require intervention strategies that aim to lock up sediment and extensive replanting programmes.


115

on a catchment-by-catchment basis. As indicated in the example shown in Fig. 7, in many instances management success is only likely to be attained at reasonable cost once rehabilitation outcomes have been achieved through implementation of sediment and vegetation management plans in upstream reaches.

Use of the River Styles framework in monitoring programmes

River rehabilitation and conservation programmes are increasingly numerous but are rarely systematically and consistently monitored or audited (Kondolf & Micheli, 1995). Monitoring provides the fundamental basis from which to ‘learn from mistakes’, document success and determine whether river rehabilitation strategies are achieving their intended target conditions and catchment-framed vision (Kondolf, 1995b, 1996). The River Styles framework provides a consistent physical baseline upon which additional layers of management information can be added. In New South Wales the framework has been used as a basis for making management, policy and licensing decisions relating to physical river condition and health (e.g. measures of biophysical stress, environmental flow allocations, habitat assessment, riparian vegetation surveys) and for auditing procedures (e.g. identification of reference sites for benchmarking and biomonitoring procedures). As noted in Table 2, the specific purpose to which the River Styles framework has been applied varies across different regions of New South Wales, depending on management needs. Several examples are outlined below.

River health/biomonitoring A basic prerequisite in assessing river condition (or health) is that representative sampling programmes are utilized to compare like with like (Boulton, 1999). Consistent application of the River Styles framework allows a statewide comparison to be made of the biological health and the effects of environmental flows on reaches of the same style. NSW DLWC staff use River Styles maps to guide the selection of representative sampling points in stream health assessment. The number of samples per style is based on the relative length of that style to the others in the catchment (the longer the length of the style, the more samples collected). These principles apply to biomonitoring projects undertaken by NSW DLWC that require the identification of physically homogeneous reaches. This includes the Integrated Monitoring of Environmental Flows (IMEF) project on regulated rivers in New South Wales, where selection of physically homogeneous reaches is based on water use in the reach, the adjacent land uses and the River Style. Physical stream changes caused by environmental flows are also being analysed using the River Styles framework. The ‘natural’ behaviour of the style in the monitored reach is used to assess the most likely locations of geomorphic change and thus determine the placement of cross-sections and long sections to monitor that change.

116


Water allocation licences It is a condition of many water extraction licences in New South Wales that pumping may not start until the gauge at a certain location reaches a certain height. When these gauges are being established, the licence reach and the River Style are crossreferenced. In this way, water extraction can be controlled in a way that is compatible with the behaviour of that style. For example, water extraction would be prohibited on a stream with the meandering sand-bed style if it significantly decreased the low flow necessary to keep the bank-toe vegetation alive and prevent accelerated lateral migration. Conversely, there would be less restriction on a stream within a confined valley setting where bedrock margins limit geomorphic change. Another concern is the maintenance of low-flow-stage refugia. For example, a chain-of-ponds style maintains base flow conditions during extended dry spells, while pools along a meandering gravel-bed river provide a fundamental refuge at low-flow stage. In contrast, maintenance of refugia over the relatively planar bed of a meandering finegrained style will require a different water allocation strategy. Water allocation and environmental flow initiatives should be framed in full recognition of the variability of different River Styles. Environmental flow water quality policy The natural range of water quality and turbidity varies between River Styles. For example, fine-grained styles tend to be more turbid than gravel-bed styles. Hence, the River Styles framework provides a basis for calibrating water quality initiatives. NSW DLWC are using River Styles information to determine strategies and policies for water quality aspects of environmental flows. Accelerated stream-bed and bank erosion is often the most likely source of sediment and nutrient overloads in downstream locations (cf. Wasson, Mazari, Starr, & Clifton, 1998; Gell, Wallbrink, Tassicker, & Illman, 1999; Fryirs & Brierley, 2001). Accordingly, information on the behaviour, condition, recovery potential and conservation category of each style is used to decide on strategies and priorities for sediment control by means of river rehabilitation in the catchment.

Lessons learnt in applying the River Styles framework It is recognized implicitly that the River Styles framework is scientifically based, while decision-making in river management is a consultative process, driven by a range of agendas among multiple stakeholders (cf. Smith, 1998; Conacher & Conacher, 2000). In striving towards a ‘shared’ biophysical vision of what is achievable and what is desirable for catchment-framed river rehabilitation programmes, application of the River Styles framework provides an initial basis for discussion and a proactive template for management actions. This template is based on the physics of hydraulics and therefore provides the most compelling and uncompromising factor when considering management actions. However, recommendations from River Styles analyses must be merged with community aspirations in the development of viable, effective, catchment-framed river management visions and programmes.


117

Collective ownership of management plans is required if long-term programmes are to achieve sustainable outcomes (cf. Rogers & Bestbier, 1997). For example, empowerment is critical in the development of maintenance plans for river works, such as on-the-ground responses following flood events, and weed management programmes. River management must continue regardless of limitations of knowledge. In all instances, however, it is advisable that the precautionary principle is observed, and best use made of available evidence in a conservative manner. Many Rivercare groups in New South Wales have shown considerable ingenuity in designing river rehabilitation plans. So long as these plans work with the behaviour of the river, the local group takes ownership of the experimental designs, and appropriate auditing procedures are put in place (and documented), these developments are to be encouraged (cf. Kondolf & Micheli, 1995). Collective commitment to a process of learning will yield significant advances in rehabilitation measures. Application of the River Styles framework provides a rational basis by which lessons learnt in one reach can be meaningfully applied elsewhere (i.e. for an equivalent type of river character and behaviour). However, in all these applications, appropriately documented procedures for rigorous auditing programmes are critical if the best environmental outcomes are to be achieved, both now and into the future. To facilitate adoption of the River Styles framework, ensuring that a suitable communication tool is provided for end-users, the procedure was developed and applied in collaboration with applied geomorphologists and river managers in NSW DLWC. This association has been invaluable in the adoption of this research tool. Community-based workshops and field days have been used to increase understanding of issues, scope views and define achievable goals within a specified time-frame. This has ensured that potential benefits and limitations of available data and understanding are fully appreciated.

Conclusions The River Styles framework represents a research tool developed by geomorphologists that is being used by state agency personnel to understand river character and behaviour and implement effective, sustainable, on-the-ground management practices that work with nature. The procedure provides a rigorous scientific basis for assessing a range of biophysical processes and provides a consistently applied template upon which effective management decision-making can take place. Given its process-based origins, and its emphasis on the evolutionary nature of river courses, the River Styles framework provides a basis for rehabilitation programmes that move beyond visual appraisals of river character. It can be applied in any environmental setting. Analysis of biophysical linkages throughout a catchment, and interpretation of geomorphic condition and recovery potential, allow practitioners to make consistent comparisons between different river systems. Collaboration with NSW DLWC staff and local stakeholders in applying the River Styles framework has formed part of a transitional process in many parts of New

118


South Wales in which proactive rehabilitation strategies now address the causes rather than the symptoms of river degradation, based on solid understanding of biophysical processes. In a sense, a paradigm shift is under way, as River Styles maps and reports are communicated to river management decision-makers through: 앫 internal NSW DLWC procedures used to assess proposals for the development of land (public and private) near rivers; 앫 making River Styles information available to local government planners, and 앫 using River Styles information when advising community groups and land owners about river management issues. These changes signify increased recognition of the need to develop management programmes that work with nature, and the fundamental significance of geomorphic insights in designing such programmes. Indeed, it must be asked how sustainable management programmes can be designed and implemented independently from these insights. However, much work remains to be completed in obtaining primary baseline information on river character and behaviour across much of the Australian continent.

Acknowledgements A registered trademark for the River Styles framework is held by Macquarie University and the Land and Water Australia (LWA). The trademark and the River Styles accreditation procedure is administered through Macquarie Research Limited (MRL). Funding and support for the development and application of the framework has come from a number of sources including LWA, Head Office of NSW DLWC, the Natural Heritage Trust (NHT), The Far South Coast Catchment Management Committee, Bega Valley Shire and the North Coast Region of NSW DLWC. Regional officers who provided information regarding the use of the River Styles framework are thanked. The people of the Bega Valley, in particular Wolumla catchment, are also thanked for providing access to properties and their participation in numerous projects undertaken by the authors. Two anonymous referees provided insightful and helpful comments that assisted the communication and contribution of this manuscript.

References Abernethy, B., & Rutherfurd, I. D. (1998). Where along a river’s length will vegetation most effectively stabilise stream banks? Geomorphology, 23(1), 55–75. Boon, P. J. (1992). Essential elements in the case for river conservation. In P. J. Boon, P. Calow, & G. E. Petts (Eds.), River conservation and management (pp. 11–33). Chichester: Wiley. Boulton, A. J. (1999). An overview of river health assessment: philosophies, practice, problems and prognosis. Freshwater Biology, 41, 469–479.


119

Bradshaw, A. D. (1996). Underlying principles of restoration. Canadian Journal of Aquatic Science, 53(Suppl. 1), 3–9. Brierley, G. J. (1996). Channel morphology and element assemblages: a constructivist approach to facies modelling. In P. Carling, & M. Dawson (Eds), Advances in fluvial dynamics and stratigraphy (pp. 263–298). Chichester: Wiley Interscience. Brierley, G. J. (1999). River Styles: an integrative biophysical template for river management. In I. Rutherfurd, & R. Bartley (Eds). Proceedings of the Second Stream Management Conference (Vol. 1 pp. 93– 100). Melbourne: CRC for Catchment Hydrology. Brierley, G. J., & Fryirs, K. (1998). A fluvial sediment budget for Upper Wolumla Creek, South Coast, New South Wales, Australia. Australian Geographer, 29(1), 107–124. Brierley, G. J., & Fryirs, K. (1999). Tributary-trunk stream relations in a cut-and-fill landscape: a case study from Wolumla catchment, N.S.W., Australia. Geomorphology, 28, 61–73. Brierley, G. J., & Fryirs, K. (2000). River Styles, a geomorphic approach to catchment characterisation: implications for river rehabilitation in Bega catchment, New South Wales, Australia. Environmental Management, 25(6), 661–679. Brierley, G. J., Cohen, T., Fryirs, K., & Brooks, A. (1999a). Post-European changes to the fluvial geomorphology of Bega Catchment, Australia: implications for river ecology. Freshwater Biology, 41, 1–10. Brierley, G. J., Ferguson, R. J., Lampert, G., Cohen, T., Fryirs, K., Reinfelds, I., Goldrick, G., Crighton, P., Batten, P., & Jansen, J. (1999b). Summary Overview of River Styles in North Coast Catchments of New South Wales. Macquarie Research Limited Report for NSW Department of Land and Water Conservation. pp. 55. Brookes, A. (1995). River channel restoration: theory and practice. In A. Gurnell, & G. E. Petts (Eds), Changing river channels (pp. 369–388). Chichester: Wiley. Brooks, A. (1999a). Large woody debris and the geomorphology of a perennial river in southeast Australia. In I. Rutherfurd, & R. Bartley (Eds). Proceedings of the Second Stream Management Conference, (Vol. 1 pp. 129–136). Melbourne: CRC for Catchment Hydrology. Brooks, A. (1999b). Lessons for river managers from the fluvial tardis (Direct insights into post-European channel changes from a near-intact alluvial river). In I. Rutherfurd, & R. Bartley (Eds). Proceedings of the Second Stream Management Conference, (Vol. 1 pp. 121–128). Melbourne: CRC for Catchment Hydrology. Brooks, A. P., & Brierley, G. J. (1997). Geomorphic responses of lower Bega River to catchment disturbance, 1851-1926. Geomorphology, 18, 291–304. Brooks, A. P., & Brierley, G. J. (2000). The role of European disturbance in the metamorphosis of lower Bega River. In S. A. Brizga, & B. L. Finlayson (Eds), River management: the Australasian experience (pp. 221–246). Chichester: Wiley. Brookes, A., & Sear, D. A. (1996). Geomorphological principles for restoring channels. In A. Brookes, & F. D. Shields Jr. (Eds), River channel restoration: guiding principles for sustainable projects (pp. 75– 101). Chichester: Wiley. Brookes, A., & Shields, F. D. Jr. (1996). Perspectives on river channel restoration. In A. Brookes, & F. D. Shields Jr. (Eds), River channel restoration: guiding principles for sustainable projects (pp. 1– 19). Chichester: Wiley. Cairns, J. (1989). Restoring damaged ecosystems: is predisturbance condition a viable option? The Environmental Professional, 11, 152–159. Church, M. (1992). Channel morphology and typology. In P. Calow, & G. E. Petts (Eds), The rivers handbook: hydrological and ecological principles (pp. 126–143). Oxford: Blackwell Science. Conacher, A., & Conacher, J. (2000). Environmental planning in Australia. Melbourne: Oxford University Press. Downs, P. W. (1995a). River channel classification for channel management purposes. In A. Gurnell, & G. E. Petts (Eds), Changing river channels (pp. 347–365). Chichester: Wiley. Downs, P. W. (1995b). Estimating the probability of river channel adjustment. Earth Surface Processes and Landforms, 20, 687–705. Downs, P. W., & Brookes, A. (1994). Developing a standard geomorphological approach for the appraisal of river projects. In C. Kirkby, & W. R. White (Eds), Integrated river basin development (pp. 299– 310). Chichester: Wiley.

120


Downs, P. W., & Gregory, K. J. (1994). Sensitivity analysis and river conservation sites: a drainage basin approach. In D. O’Halloran, C. Green, M. Harley, M. Stanley, & J. Knill (Eds), Geological and landscape sensitivity (pp. 139–143). London: Geological Society. Downs, P. W., & Thorne, C. R. (1996). A geomorphological justification of river channel reconnaissance surveys. Transactions of the Institute of British Geographers, 21, 455–468. Erskine, W. D., & Webb, A. A. (1999). A protocol for river rehabilitation. In I. Rutherfurd, & R. Bartley (Eds). Proceedings of the Second Stream Management Conference, (Vol. 1 pp. 237–243). Melbourne: CRC for Catchment Hydrology. Fryirs, K., & Brierley, G. J. (1998). The character and age structure of valley fills in upper Wolumla Creek catchment, South Coast, New South Wales. Earth Surface Processes and Landforms, 23, 271–287. Fryirs, K., & Brierley, G. J. (1999). Slope-channel decoupling in Wolumla catchment, N.S.W., Australia: the changing nature of sediment sources following European settlement. Catena, 35, 41–63. Fryirs, K., & Brierley, G. J. (2000). A geomorphic approach to the identification of river recovery potential. Physical Geography, 21(3), 244–277. Fryirs, K., & Brierley, G. J. (2001). Variability in sediment delivery and storage along river courses in Bega catchment, NSW, Australia: implications for geomorphic river recovery. Geomorphology, 38, 237–265. Gell, P., Wallbrink, P., Tassicker, G., & Illman, M. (1999). Secrets in the sediments: a history of sediment and pollution loads in the lower Torrens River, S.A. In I. Rutherfurd, & R. Bartley (Eds). Proceedings of the Second Stream Management Conference, (Vol. 1 pp. 287–292). Melbourne: CRC for Catchment Hydrology. Goldrick, G., Brierley, G. J., & Fryirs, K. (1999). River Styles in the Richmond Catchment. Report to the NSW Department of Land and Water Conservation, Macquarie Research Limited. Gore, J. A. (Ed.). (1985). The restoration of rivers and streams: theories and experience. Boston, MA: Butterworth. Gore, J. A., Kelly, J. R., & Young, J. D. (1990). Application of ecological theory to determining recovery potential of disturbed lotic ecosystems: Research needs and priorities. Environmental Management, 14, 755–762. Grant, G. E., Swanson, F. J., & Wolman, M. G. (1990). Pattern and origin of stepped-bed morphology in high-gradient streams, Western Cascades, Oregon. Geological Society of America Bulletin, 102, 340–352. Harper, D. M., Ebrahimnezhad, M., Taylor, E., Dickinson, S., Decamp, O., Verniers, G., & Balbi, T. (1999). A catchment-scale approach to the physical restoration of lowland UK rivers. Aquatic Conservation: Marine and Freshwater Ecosystems, 9, 141–157. Hickin, E. J. (1984). Vegetation and river channel dynamics. Canadian Geographer, 28(2), 111–126. Hobbs, R. (1997). Future landscapes and the future of landscape ecology. Landscape and Urban Planning, 37, 1–9. Hupp, C. R. (1992). Riparian vegetation recovery patterns following stream channelisation: a geomorphic perspective. Ecology, 73(4), 1209–1226. Imhof, J. G., Fitzgibbon, J., & Annable, W. K. (1996). A hierarchical evaluation system for characterising watershed ecosystems for fish habitat. Canadian Journal of Fisheries and Aquatic Science, 53(Suppl. 1), 312–326. Kemp, J. L., Harper, D. M., & Crossa, G. A. (1999). Use of ‘functional habitats’ to link ecology with morphology and hydrology in river rehabilitation. Aquatic Conservation: Marine and Freshwater Ecosystems, 9, 159–178. Koehn, J. D., Brierley, G. J., Cant, B. L., & Lucas, A. M., (2001). River restoration framework (online), Canberra: Land and Water Australia (Occasional Paper 01/01: http://www.lwa.gov.au cited 21 May 2001). Kondolf, G. M. (1995a). Geomorphological stream classification in aquatic habitat restoration: uses and limitations. Aquatic Conservation: Marine and Freshwater Ecosystems, 5, 127–141. Kondolf, G. M. (1995b). Five elements of effective evaluation of stream restoration. Restoration Ecology, 3(2), 133–136. Kondolf, G. M. (1996). A cross section of stream channel restoration. Journal of Soil and Water Conservation, 51, 119–126.


121

Kondolf, G. M. (1998). Lessons learned from river restoration projects in California. Aquatic Conservation: Marine and Freshwater Ecosystems, 8, 39–52. Kondolf, G. M., & Downs, P. W. (1996). Catchment approach to planning channel restoration. In A. Brookes, & F. D. Shields Jr. (Eds), River channel restoration: guiding principles for sustainable projects (pp. 129–148). Chichester: Wiley. Kondolf, G. M., & Larson, M. (1995). Historical channel analysis: techniques for application to riparian and aquatic habitat restoration. Aquatic Conservation: Marine and Freshwater Ecosystems, 5, 109– 126. Kondolf, G. M., & Micheli, E. R. (1995). Evaluating stream restoration projects. Environmental Management, 19(1), 1–15. Ladson, A. R., & Tilleard, J. W. (1998). Ensuring stream rehabilitation works carried out under NHT funding are successful and effectively targeted. In I. D. Rutherfurd, A. R. Ladson, J. W. Tilleard, M. J. Stewardson, S. A. Ewing, G. Brierley, & K. Fryirs (Eds), Research and development needs for river restoration in Australia (pp. 45–50). Canberra: Land and Water Resources Research and Development corporation (Occasional Paper 15/98). Maddock, I. (1999). The importance of physical habitat assessment for evaluating river health. Freshwater Biology, 41, 373–391. Mackenzie, J. A., van Coller, A. L., & Rogers, K. H. (1999). Rule based modelling for management of riparian systems. Report to the Water Research Commission (Report no. 813/1/99). Pretoria, South Africa. Millar, R. G. (2000). Influence of bank vegetation on alluvial channel patterns. Water Resources Research, 36(4), 1109–1118. Miller, J. R., & Ritter, J. B. (1996). An examination of the Rosgen classification of natural rivers. Catena, 27, 295–299. Milner, A. M. (1994). System recovery. In P. Calow, & G. E. Petts (Eds), The rivers handbook. Oxford: Blackwell Science. Montgomery, D. R., & Buffington, J. M. (1997). Channel reach morphology in mountain drainage basins. Geological Society of America Bulletin, 109, 596–611. Mosley, M. P. (1987). The classification and characterisation of rivers. In K. S. Richards (Ed.), River channels: environment and process (pp. 295–320). Oxford: Blackwell. Naiman, R. J., Lonzarich, D. G., Beechie, T. J., & Ralph, S. C. (1992). General principles of classification and the assessment of conservation potential in rivers. In P. J. Boon, P. Calow, & G. E. Petts (Eds), River conservation and management (pp. 93–123). Chichester: Wiley. Nanson, G. C. (1986). Episodes of vertical accretion and catastrophic stripping: a model of disequilibrium floodplain development. Geological Society of America Bulletin, 97, 1467–1475. Newson, M. D. (1992). River conservation and catchment management: a UK perspective. In P. J. Boon, P. Calow, & G. E. Petts (Eds), River conservation and management (pp. 385–395). Chichester: Wiley. Newson, M. D. (1994). Sustainable integrated development and the basin sediment system: guidance from fluvial geomorphology. In C. Kirkby, & W. R. White (Eds), Integrated river basin development (pp. 1–10). Chichester: Wiley. Newson, M. D., Clark, M. J., Sear, D. A., & Brookes, A. (1998). The geomorphological basis for classifying rivers. Aquatic Conservation: Marine and Freshwater Ecosystems, 8, 415–430. Penn, L. J. (1999). Managing our rivers: a guide to the nature and management of the streams of southwest Western Australia. Perth: Water and Rivers Commission. Poff, N. L., & Ward, J. V. (1990). Physical habitat template of lotic systems: recovery in the context of historical pattern of spatiotemporal heterogeneity. Environmental Management, 14(5), 629–645. Raven, P. J., Fox, P., Everand, M., Holmes, N. T. H., & Dawson, F. H. (1997). River habitat survey: a new system for classifying rivers according to their habitat quality. In P. J. Boon, & D. L. Howell (Eds), Freshwater quality: defining the indefinable? (pp. 215–234). Edinburgh: The Stationery Office. Renwick, W. H. (1992). Equilibrium, disequilibrium and non-equilibrium landforms in the landscape. Geomorphology, 5, 265–276. Rogers, K., & Bestbier, R. (1997). Development of a protocol for the rehabilitation of the desired state of riverine systems in South Africa. Pretoria: Department of Environmental Affairs and Tourism. Rosgen, D. L. (1994). A classification of natural rivers. Catena, 22, 169–199.

122


Rosgen, D. L. (1996). Applied river morphology. Pagosa Springs, CO: Wildland Hydrology. Rowntree, K. M., & Wadeson, R. A. (1999). A hierarchical geomorphological model for the classification of selected South African rivers. Pretoria: Water Research Commission (Report No. 497/1/99). Rust, B. R. (1978). A classification of alluvial channel systems. In A. D. Miall (Ed.), Fluvial sedimentology (pp. 187–198). Calgary: Canadian Society of Petroleum Geologists (Memoir 5). Rutherfurd, I., Jerie, K., Walker, M., & Marsh, N. (1999). Don’t raise the Titanic: how to set priorities for stream rehabilitation. In I. Rutherfurd, & R. Bartley (Eds), Proceedings of the Second Stream Management Conference, (vol. 2) (pp. 527–532). Melbourne: CRC for Catchment Hydrology. Rutherfurd, I., Jerie, K., Walker, M., & Marsh, N. (2000). A rehabilitation manual for Australian streams (vol. 1). Canberra: Land and Water Resources Research and Development Corporation. Schumm, S. A. (1973). Geomorphic thresholds and complex response of drainage systems. In M. Morisawa (Ed.), Fluvial geomorphology (pp. 299–310). Binghamton, NY: Publications in Geomorphology. Schumm, S. A. (1977). The fluvial system. New York: Wiley Interscience. Sear, D. A. (1994). River restoration and geomorphology. Aquatic Conservation: Marine and Freshwater Ecosystems, 4, 169–177. Sear, D. A. (1996). The sediment system and channel stability. In A. Brookes, & F. D. Shields Jr. (Eds), River channel restoration: guiding principles for sustainable projects (pp. 149–177). Chichester: Wiley. Sear, D. A., Newson, M. D., & Brookes, A. (1995). Sediment-related river maintenance: the role of fluvial geomorphology. Earth Surface Processes and Landforms, 20, 629–647. Simon, A. (1989). A model of channel response in disturbed alluvial channels. Earth Surface Processes and Landforms, 14, 11–26. Smith, D. I. (1998). Water in Australia. Melbourne: Oxford University Press. Southwood, T. R. E. (1977). Habitat, the template for ecological strategies? Journal of Animal Ecology, 46, 337–365. Taylor, M. P., Thomson, J. R., Fryirs, K., & Brierley, G. J. (2000). Habitat assessment using the River Styles methodology. Ecological Management and Restoration, 1(3), 223–226. Wasson, R. J., Mazari, R. K., Starr, B., & Clifton, G. (1998). The recent history of erosion and sedimentation on the Southern Tablelands of southeastern Australia: sediment flux dominated by channel incision. Geomorphology, 24, 291–308. Zierholz, C., Prosser, I. P., Fogarty, P. J., & Rustomji, P. (2001). In-stream wetlands and their significance for channel infilling and the catchment sediment budget, Jugiong Creek, New South Wales. Geomorphology, 38, 221–235.

Application of the River Styles framework as a basis for ... - CiteSeerX

Application of the River Styles framework as a basis for ... - CiteSeerX

Suggest Documents

Using ERP as a basis for Enterprise application integration - CiteSeerX

IMPLEMENTATION OF THE RIVER STYLES FRAMEWORK IN THE

IMPLEMENTATION OF THE RIVER STYLES FRAMEWORK IN THE

Using the Living Laboratory Framework as a Basis for ...

application of rhetorical styles as a determinant of the ... - UKM

using the river styles framework as a physical template upon which an ...

Soil sampling as a basis for fertilizer application. - NDSU

Electrocorticogram as the Basis for a Direct Brain Interface - CiteSeerX

RULEX & CEBP Networks As the Basis for a Rule ... - CiteSeerX

The Multi-Dimensional Hartley Transform as a Basis for ... - CiteSeerX

residential living structure as a basis for the spatial ... - CiteSeerX

The Scholar-Practitioner Model as a Basis for Promoting ... - CiteSeerX

Application Framework for Efficient Development of Sensor as a ...

Application Framework for Efficient Development of Sensor as a ...

Caches As Filters: A Framework for the Analysis of ... - CiteSeerX

climbing performance of migrating birds as a basis for ... - CiteSeerX

addenda for the application of River Habitat Survey in ... - CiteSeerX

Effectiveness of health tourism application as the basis of health ...

Differentiation of C-Nitrocompounds as the Basis for ... - CiteSeerX

Archetypical Component of the Law as a Basis to ... - CiteSeerX

A Framework for Generic Inter-Application Interaction for ... - CiteSeerX

A generic framework for a training application based on ... - CiteSeerX

The 8C Framework as a Reference Model for ... - CiteSeerX

The Precautionary Principle as a Framework for ... - CiteSeerX