Abstract:
Riparian vegetation plays a cornerstone role in the natural functioning of many facets of the river environment. This is particularly so in the context of bank stability and erosion, which is achieved via mechanical, hydrological and hydraulic influences on river channels. As such, riparian vegetation plays a pivotal role in many river rehabilitation initiatives, particularly so where bank erosion is a concern and ‘soft’ management options are the preferred. Of late, river management has raised questions around ‘bang for your buck’ river management, where strategic locations within a river catchment are targeted during management initiatives. Such management initiatives should be guided by field-based information within geomorphicallygrounded spatial frameworks, as it is ultimately geomorphic processes (e.g. water and sediment flux, reach-scale morphometric parameters, etc.) that control the development and maintenance of riparian vegetation, as well as the processes responsible for bank erosion and channel degradation. In New Zealand, the current spatial framework used (the River Environment Classification, or REC) is a coarse-scale, GIS-based information package that does not explicitly address the variables that must be analysed for successful riparian (and river) management. As such, this research intends to incorporate the use of an alternative spatial framework (the River Styles framework) with supplementary, finer scale analysis of geomorphic and vegetative attributes, and proposes a conceptual decision making model for strategic riparian planting. The attributes analysed have been extracted from three decades worth of academic research and literature. The Hoteo River catchment in the north of the Auckland region has been used as a case study for this conceptual model, whereby strategic riparian management locations have been devised on a catchment-wide scale using fieldbased information, along with supplementary insights from spatio-temporal, GIS-based analysis.
