Outline of the River Styles® Framework
“River management programs that ‘work with nature’ must respect the inherent diversity and behaviour of aquatic ecosystems.”
Rivers show a remarkable diversity of river character and behaviour in any catchment. Human activities, whether purposeful or otherwise have impacted significantly on the inherent patterns and rates of river adjustment, altering what rivers look like and how they behave. This has impacted on the structure and function of aquatic ecosystems. The River Styles framework outlines a generic set of procedures that provides tools for interpreting river character, behaviour, condition and recovery potential. The explanatory and predictive basis of the framework provides a rigorous foundation for management decision making.
River management programs that ‘work with nature’ must respect the inherent diversity and behaviour of aquatic ecosystems. Each catchment should be managed in its own right, recognising the patterns and connectivity of river forms and processes. These are shaped by the configuration of the system and responses to natural and/or human induced disturbance events. Applications of the River Styles framework generate a coherent package of geomorphic information, providing a physical template for river rehabilitation activities.
The catchcry of the River Style framework is ‘Know your catchment’ that encompasses four key principles:
- Respect river diversity
- Work with river dynamic behaviour and change
- Work with linkages of biophysical processes
- Use geomorphology as an integrated physical template for river management activities
Scientific and Management Values
Works with natural diversity
River Styles works with the natural diversity of river forms and processes. Due recognition is given to the continuum of river morphology, extending from bedrock-imposed conditions to fully alluvial variants (some of which may comprise unincised valley floors). The River Styles framework can be applied in any environmental setting.
River Styles provides a catchment-framed baseline survey of river character and behaviour throughout a catchment. Application of a nested hierarchical arrangement enables the integrity of site-specific information to be retained in analyses applied at catchment or regional levels. Downstream patterns and connections among reaches are examined, demonstrating how disturbance impacts in one part of a catchment are manifest elsewhere over differing timeframes. Controls on river character and behaviour, and downstream patterns of River Styles, are explained in terms of their physical setting and prevailing biophysical fluxes.
Generic and open-ended
River Styles is framed in terms of generic, open-ended procedures that are applied in a catchment-specific manner. Reaches are not ‘pigeon-holed’ into rigid categories; rather, new variants are added to the existing range of River Styles based on a set of discrete attributes (i.e. the valley setting, geomorphic unit assemblage, channel planform, and bed material texture).
River Styles evaluates recent river changes in context of longer-term landscape evolution, framing river responses to human disturbance in context of the ‘capacity for adjustment’ of each River Style. Identification of reference conditions provides the basis to determine how far from its ‘natural’ condition the contemporary river sits and interpret why the river has changed. Analysis of reaches at differening stages of geomorphic adjustment at differing localities (ie space-time transformation or ergodic reasoning) is applied to interpret evolutionary pathways for reaches of the same type.
Evaluates river behaviour
River Styles evaluates river behaviour, indicating how a river adjusts within its valley setting. This is achieved through appraisal of the form-process associations of geomorphic units that make up each River Style. Assessment of these building blocks of rivers, in both channel and floodplain zones, guides interpretation of the range of behaviour within any reach. As geomorphic units include both erosional and depositional forms, and characterise all riverscapes, they provide an inclusive and integrative tool for classification exercises.
Geomorphic condition and recovery potential
River Styles provides a meaningful basis to compare type-with-type. From this, the contemporary geomorphic condition of the river is assessed. Analysis of downstream patterns of River Styles and their changes throughout a catchment, among other considerations, provides key insights with which to determine geomorphic river recovery potential. This assessment, in turn, provides a physical basis to predict likely future river structure and function.
Key Management Applications
Nested hierarchy of physical information
River Styles provides a basis to order a nested hierarchy of physical information in a consistent, coherent, and integrative manner, presenting a systematic and meaningful basis for communication. From this, information gaps, and the need for more detailed assessments of biophysical information, can be determined. Catchment-framed assessments provide a template onto which finer scale resolution work can be added, without compromising the integrity of the information base for the catchment as a whole.
Determination of target conditions
River Styles determines realistic ‘target conditions’ for river rehabilitation, focusing management attention on underlying causes of ‘problems’, rather than the symptoms of change. This enables specific river rehabilitation treatments to be designed.
Template for evaluation
River Styles shows how the physical structure of rivers throughout a catchment provides a template to evaluate interactions of biophysical processes. A consistent basis is provided to appraise issues of uniqueness, rarity, naturalness, geodiversity, and representativeness.
Prioritisation of resources
River Styles can be used to more effectively prioritise resource allocation to management issues, balancing efforts at river conservation and rehabilitation. This requires differentiation of reaches of high conservation value (in terms of the geodiversity and/or rarity of River Styles) and degraded or stressed rivers. Priorities can be determined within- and between-catchments, presenting an open and transparent physical basis for decision-making.
River Styles helps to develop proactive, rather than reactive, management strategies that ‘work with nature’, ensuring that site-specific strategies are linked within a reach and catchment-based ‘vision’.
Monitoring and auditing
River Styles can be used to select representative or reference sites across the range of River Styles in programs to monitor river condition and audit the effectiveness of river management strategies. These benchmarking and monitoring procedures can be applied at scales ranging from within-catchment programs through to regional, State or even National river management programs. For example, classification of wild and scenic rivers can be undertaken to determine the ‘best remaining reaches’ of different types of rivers, providing an appraisal of which components of diversity and functioning have been compromised and whether these trends can be reversed.