human activities in the fields of agriculture, municipal and industry introduce significant amounts of nutrients and organic materials into the rivers and streams resulting in their contamination. computer models such as qual2kw are used extensively for water quality management of rivers and streams. the qual2kw model is a one dimensional, non-uniform, steady water quality model, which has been...

the morphological river evolution at long-time (centuries and even millennia) and large spatial scale (watersheds of several square kilometres) can be described by means of simplified 1d models, able to simulate the variation of bed elevation and grain size composition at non-detailed scales, involving a reduced computational effort. the erosion and deposition phenomena acting along rivers can ...

most previous laboratory studies of local scour at bridge abutments were performed in rectangular channels in which the distributions of flow velocity and bed shear stress were considered uniform in the transverse direction. in reality however, bridge abutments are usually located in the floodplain zone of rivers where velocity and shear stress distributions are directly affected by the lat...

Nutrient inputs from rivers play an important role in lake eutrophication. To compare the forms characteristics of phosphorus (P) and nitrogen (N) in rivers flowing through rural and urban areas, water samples were collected seasonally from five urban rivers and six rural rivers flowing to Lake Chaohu, China. Higher total phosphorus (TP), particulate phosphorus (PP), soluble reactive phosphorus...

Rivers can shape diverse landscapes, determine the spatial connectivity of river and terrestrial life, provide a variety resources services. are often over-bound due to need for flood control irrigation. affected by human disturbance require restoration improve ecosystem services they provide. Environmental heterogeneity is generally considered be non-uniform variation environmental elements in...

The Protocolised Management in Sepsis (ProMISe) trial (April 2 issue) completes a trio of studies that question the further application of early, goal-directed therapy (EGDT) as suggested by Rivers et al. In particular, these trials consistently show no survival benefit with regard to the mandated use of central venous oxygen saturation (ScvO2) monitoring. However, it remains questionable wheth...

1. Compared with rivers in more humid, forested ecoregions of eastern and midwestern U.S.A., rivers in semi-arid grassland of the U.S. Great Plains tend to be relatively shallow, more variable in discharge, and characterised by high suspended sediment loads. Although critical life stages of fish in prairie rivers probably depend at least partially on zooplanktonic food, data on community and di...

The Neotropical Ambrysus stali La Rivers species complex is reviewed and includes A. bifidus La Rivers & Nieser, A. scolius La Rivers, A. stali La Rivers, and A. tricuspis La Rivers. Ambrysus oblongulus Montandon is removed as a member of this complex. Features uniting these species are related to male genitalia and associated structures. Ambrysus maya n. sp. is the fifth species in the complex...