Browsing All Posts filed under »flow«

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 […]

How fish negotiate culverts

March 27, 2017

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While culverts are designed to facilitate the movement of water by allowing it to flow under roads or other obstructions, they can place physiological and/or behavioural restrictions on the movements of fish. Although several studies have considered the implications of culvert design for fish passage, surprisingly few have tried to identify the factors that influence […]

Green covers improve drainage channels

June 1, 2016

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In urban environments, the ubiquity of impervious surfaces increases rainfall runoff and the risk of flash flooding. These problems can be addressed by widening and deepening drainage canals, but usually at the risk of further habitat degradation. As a result, there ‘s increasing interest in low-impact environmentally-sensitive designs that simultaneously improve flood control and ecosystem […]

How environmentally-damaging are run-of-river hydropower systems?

June 1, 2016

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Hydropower generation typically involves the creation of large dams for the storage and release of water, which can have serious adverse effects on riverine environments. However, growing pressures on governments to meet renewable energy targets have stimulated interest in small-scale hydropower systems, especially run-of-river schemes, which use the flow within a river channel and operate […]

Flow-on effects of water movement

March 23, 2016

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Although aquatic plants risk being uprooted in fast-flowing streams, if they’re capable of varying their growth form to suit the conditions they may be able to reduce the chance of dislodgement. To see if water plants can adapt to fast-moving water by increasing their strength and reducing their drag, Swedish researchers compared the growth of […]

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 […]