Browsing All Posts filed under »geology«

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 river transport affects dissolved organic matter

December 13, 2016

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In most rivers, the downstream transport of dissolved organic matter (DOM) makes large amounts of energy available to aquatic ecosystems. The River Continuum Concept (RCC) of Vannote et al. (1980) provided a useful framework for studying the influence of organic material from headwater streams on the structure and function of downstream ecosystems. The RCC hypothesized […]

Do pollutants bar amphibians from stormwater ponds?

December 18, 2015

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Because of the complex array of ecologically threatening processes in urban environments, our understanding of the role that artificial ponds play in allowing aquatic populations to persist in towns and cities is quite limited. Together with green roofs, swales and stream buffers, stormwater ponds are key instruments in runoff management, but by retaining sediment as […]

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 […]

Bank collapse predicted by asset profile and liquidity

December 16, 2014

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Although the downstream movement of flowing water is the most obvious cause of riverbank erosion, seepage erosion is also significant. When the water level in a stream is high, water fills the spaces in the bank soil, and then returns to the channel again as the water level falls. This return movement can cause seepage […]

Modelling lake metabolism: don’t forget catchment factors

September 23, 2013

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Lakes vary widely in terms of their ability to sustain living (metabolic) processes.  We know that the key metabolic processes of gross primary production (GPP) and respiration (R ) are driven by physical and chemical conditions in lakes – in particular, light penetration, temperature, physical mixing, nutrients and organic matter.  At the same time, these […]