Browsing All Posts filed under »hydraulics«

Erasing the boundaries

June 19, 2017

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The new discipline of ecohydraulics considers the effects of water movement in aquatic ecosystems and blends ideas and techniques from aquatic ecology and engineering hydraulics. A central challenge for ecohydraulics is to reconcile differences between hydraulic engineers and ecologists in terms of the spatial and/or temporal scale of the processes that they tend to deal […]

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 […]

Creating fast flow refuges in streams

October 15, 2015

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Hydroelectric power plants create frequent, intense pulses in downstream river flow (hydropeaking) that are typically accompanied by increased sediment movement, high turbidity and habitat scouring. These changes can affect several aspects of the biology of fishes, including migration, spawning, early development and growth. In Switzerland, a 60% decline in catches of brown trout since 1980 […]

Photosynthesis slows the flow

March 23, 2015

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Mats of filamentous freshwater algae play an important ecological role by helping to cycle nutrients, by forming complex three-dimensional structures that can be colonised by diatoms, bacteria and microalgae, and by providing refuge for small animals. The productivity of algal mats is limited mainly by light, nutrients and grazing activity, all of which are affected […]

When ponds are fertile, mussels aren’t

December 16, 2014

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Freshwater mussels help to maintain water quality by filtering suspended particles and reducing concentrations of heavy metals, pesticides and other pollutants. Unfortunately, however, freshwater mussels are experiencing dramatic declines around the world. It’s been suggested that heightened levels of suspended solids, associated with agriculture and urban development, are responsible for the decline, but the mechanism […]