نتایج جستجو برای: fluvial current
تعداد نتایج: 781632 فیلتر نتایج به سال:
Large rivers and their riparian zones are hot spots of biodiversity (WARD et al. 1999). Fluvial geomorphic processes provide the habitat diversity and the specific habitat conditions for characteristic species assemblages and result in high levels of habitat diversity, local species richness (α-diversity), and between-habitat differences (beta-diversity) and consequently, overall species richne...
Fluvial systems carve the Earth's surface under influence of climate and tectonics. This process tends towards dynamic equilibrium conditions, in which rivers respond by regularizing their longitudinal profiles to a graded form. However, external forcings frequently interrupt this trend displacing system transient state from will evolve again with tendency In bedrock incising rivers, profile sh...
Impacts of effluent from fish farming activities on fluvial ecosystems lead to deterioration of water quality and changes in the macroinvertebrates assemblage. In this study, the influence of fish farm effluents on water quality and macroinvertebrates communities of Tajan River was investigated to evaluate the suitability of macroinvertebrates based on biological metrics and indices. Benthic...
The features of bad flow unit continuity and multiple layers emphesize the importance of a well pattern design for the development of a fluvial-delta reservoir. It is proposed a method to predict well pattern connectivity (WPC) based on the exploration and evaluation of wells. Moreover, the method helps evaluate the risk of well placement. This study initially establishes the parameters for cha...
سیلاب ورودی به مخزن سد حاوی مواد معلق زیاد بوده که اصطلاحاً جریان چگال (density current) نامیده می شود. این جریان در واقع جریان یک سیال درون سیال دیگر است که بوسیله اختلاف چگالی مابین آنها ایجاد می گردد. اختلاف در چگالی که باعث ایجاد نیروی رانش می گردد ممکن است ناشی از اختلاف درجه حرارت، وجود ذرات معلق جامد ویا مواد محلول باشد. در این تحقیق با توجه به آزمایشات سه بعدی انجام شده، گسترش عرضی جریان...
The human settlement of Europe during Pleistocene times was sporadic and several stages have been recognized, both from paleaoanthropological and archaeological records. If the first phase of hominin occupation (as early as 1.4 Ma) seems mainly restricted to the southern part of the continent, the second phase, characterized by specific lithic tools (handaxes), is linked to Acheulean settlement...
Phosphorus (P) export from agricultural catchments can accelerate freshwater eutrophication. Landscape-based remedial measures can reduce edge-of-field P losses. However, stream channel hydraulics and fluvial sediment properties can modify the forms and amounts of P exported by the time it reaches the catchment outlet. This study examines if land use, fluvial sediment properties, and storm flow...
Excavation of mock graves in sediments of aeolian and fluvial origin were conducted to test the bleaching efficiency of grave digging in materials that commonly host ancient burials in Australia. Grave-size pits were dug into Pleistocene aeolian sediments at Willandra Lakes and younger fluvial sediments on the Lachlan River, backfilled, and re-excavated. Samples for optical dating were taken fr...
Comparisons of paleofaunas from different facies are often hampered by the uncertainty in the variation of taphonomic processes biasing the paleoecological parameters of interest. By examining the taphonomic patterns exhibited by different facies in the same stratigraphic interval and area, it is possible to quantify this variation, and assess inter-facies comparability. The fossil assemblages ...
Grain-scale monitoring of fluvial morphology is important for the evaluation of river system dynamics. Significant progress in remote sensing and computer performance allows rapid high-resolution data acquisition, however, applications in fluvial environments remain challenging. Even in a controlled environment, such as a laboratory, the extensive acquisition workflow is prone to the propagatio...
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