Browsing All Posts filed under »erosion«

Lateral thinking on riverbank erosion

September 25, 2017

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Although bank erosion is often thought of as problem that has to be addressed through engineered stabilization, the lateral migration of meandering streams is a natural mechanism that redistributes channel sediment and maintains habitat diversity. New riparian zones are formed as sediment is deposited on the inside of bends and colonised by vegetation.  Meandering creates […]

Planting vegetation to stop stream bank erosion: where’s the evidence?

June 19, 2017

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Increased rates of stream bank erosion and sediment movement in disturbed catchments have been attributed to changes in catchment hydrology caused by land clearing, channel modification, the trampling activities of livestock and the removal of riparian vegetation. Given that these effects are human-induced, it’s commonly assumed that they can also be reversed by human intervention, […]

Dealing with river complexity

March 27, 2017

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Hydromorphology is a relatively new field that deals with the structure of hydrological systems and changes in their form over time. Many such changes are influenced by human-induced pressures. Realistic attempts to conceptualize hydromorphological forms and processes reflect the fact that rivers are complex multidimensional systems with longitudinal, lateral, vertical and temporal components, as well […]

Bioengineered riverbanks

March 23, 2016

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Streamside riparian zones support diverse and specialized plant communities and provide animal species with habitat, shelter and migratory opportunities. However, human pressures are such that measures are frequently needed to counter the problem of riverbank erosion. While bank protection has often been approached from a hard civil engineering perspective, there are ecological and aesthetic advantages […]

Stream-bed stability: differing effects of floods

December 18, 2015

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Floodwaters are often released from dams to rejuvenate channel form and aquatic habitats, but in the process, large volumes of sediment can be transferred downstream. Therefore, especially in the case of rivers where the sediment supply is limited, it’s useful to be able to predict how different flows affect particle mobilisation and retention. In a […]

Stream-bed stability: how best to measure it?

December 18, 2015

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Most research on the impacts of water flow on stream environments has been carried out in low-gradient channels. As a result, relationships between flow strength and stream bed mobility in steep mountain systems haven’t been well described. To characterise high-flow disturbance in mountain streams, an international research team investigated twenty headwater streams in the Upper […]

Drainage and river erosion

March 23, 2015

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Land-use changes and climatic trends have been held responsible for historical increases in river flow, such as those recorded in the USA over the last half-century. Higher flow rates are linked to increases in sediment load and stream turbidity, with consequent declines in the habitat quality and recreational value of rivers. To disentangle the factors […]