Flow variability plays an important role in structuring lotic communities, yet comparatively little is known about processes governing assemblage dynamics in stream ecosystems with stable environmental conditions, such as spring-fed rivers. Volcanic spring-fed rivers (hereafter spring-fed rivers) occur in geologically active landscapes of the western USA and around the globe. We sampled inverte...

danehkhoshk anticline is a typical growing anticline in kermanshah province which is located in folded zagros belt. the purpose of this research is to evaluate the effect of tectonic on the triangular facet characteristics, the drainage density and on the drainage pattern formed on anticline. dimensions of triangular facets were determined by means of quickbird satellite images and field works....

Where rivers enter the coastal zone, gradually varying non-uniform flow conditions develop in the channel. This section of the river is referred to as the backwater segment, and for large rivers, backwater flow extends many hundreds of kilometres upstream of the river outlet. Studies from the Mississippi River document a persistent backwater zone that influences sediment mobility throughout the...

Long-span bridges, as vital structures, play a very important role in economic development. Furthermore, the results of several earthquake-damaged bridges showed that their seismic behavior was different from that predicted under uniform excitation and in some cases the responses were more than predicted results. Therefore, the damaged bridges under non-uniform excitations were re-analyzed and ...

In recent years, preservation and purgation of rivers is considered by national and international organizations that have responsible of quality control and preservation of water resources. Because of providing public health, it is most important and vital in regions that cities that rivers feed drink waters and large industrial factories located near these rivers (Li et al., 1998; Pourabadei &...

So far, few studies have focused on the concept of critical flow velocity rather than bed shear stress for incipient sediment motion. Moreover, mixtures (graded sediment) and shape uniform motion condition. Different experiments were conducted at a hydraulic laboratory University Guilan in 2015 to determine parameters The aim this study is conduct comparison between graded sediments, round angu...

The 1950 I.L.O. classification of radiological abnormality in simple pneumoconiosis describes four discrete categories, but the actual amount of abnormality in an individual does not change by discrete steps. Radiological progression is the increase of a continuous variable, and methods of measuring it must deal with three problems: (1) the coarse classification into discrete categories; (2) po...

Methane (CH4 ) fluxes from world rivers are still poorly constrained, with measurements restricted mainly to temperate climates. Additional river flux measurements, including spatio-temporal studies, are important to refine extrapolations. Here we assess the spatio-temporal variability of CH4 fluxes from the Amazon and its main tributaries, the Negro, Solimões, Madeira, Tapajós, Xingu, and Pará...

The windings of rivers have long fascinated their human observers. For example, Aboriginal legend explains the sinuous pattern of the modern Finke River (Fig. 1) as the creation of the immense and powerful Rainbow Serpent as he emerged during the Dreamtime from deep waterholes. Recently in PNAS (1), a new theory for the general origin of such sinuous flow patterns was published, which follows f...