Official Journal of the Asia Oceania Geosciences Society (AOGS)
River Styles principles | Translated to a simplified understanding of: | Implemented to guide river management through: |
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Capacity for adjustment | • Whether the river can adjust laterally, vertically, or both • Where the river is likely to adjust, i.e. the spatial distribution of bank erosion • Where the river is confined and less able (or unable) to adjust • Where sediments will be deposited (aggrade) or eroded (degrade) in the channel • Whether the channel can shift (migrate, avulse) and where this might occur | • Land-use planning (e.g., where not to build infrastructure or developments) • Identification of hazardous buffer zones (flood- and erosion-risk) • Providing ‘erodible corridors’, ‘space to move’, and/or ‘channel migration zones’ guided by a working with nature principle • Strategic placement of necessary river control structures |
River diversity | • Recognizing the diverse types of river, with various rates of adjustment, and behaviour • Distinct characteristics and hydromorphological attributes • Whether the reach is sensitive or resilient | • Which reaches (parts of the river) should be prioritized for catchment action planning (e.g., for conservation value), or to maintain sediment sources to prevent downstream degradation • Different types of reach require different types of interventions |
Identifying geomorphic units | • The presence of diverse geomorphic units signifies the types of river styles • Indicates how the river behaves • Differentiates erosional or depositional features | • Understanding where different habitats are located (e.g., fishing) and recreational areas • Areas for sustainable gravel extraction |
Pattern of rivers | • Whether the pattern is unique or similar to other patterns in the catchment • Whether the boundaries between River Styles are gradual or distinct (abrupt) | • How sensitive different reaches are to pattern transitions due to changes in water or sediment supply, from upstream management decisions and climate change impacts (i.e., connectivity and offsite impacts) |
Position in catchment and controls | • Whether the reach is a source zone, transfer zone or accumulation zone • Whether the reach is situated in a low, moderate, or high energy environment • Possible geologic and tectonic influences | • Policies for extractive activities • Identification of geomorphic hazards (e.g., landslides, debris flows) • Floodplain zonation |
Tributary-trunk relationships (connectivity) | • Relative fluxes of water and sediment discharge from different parts of the catchment • Downstream changes in grain size and thus roughness and water depth during high flows | • Land-use planning in vicinity of confluences |
Know your catchment | • Regional settings and location influences the differences between catchments | • Locally appropriated management options, including socio-economic considerations and indigenous practices |
Nested hierarchical approach | • Range of analyses and approaches that can be undertaken in different scales. Top-down approach on controls on character and behaviour while bottom-up approach on interpretation of the character and behaviour | • Coordination of management approaches from different local and national government agencies |