Search results for "River"

Non-uniform Sediment Transport Estimation in Non-equilibrium Situations: Case Studies

2014

Abstract Quantitative estimate of sediment transport in alluvial channels is one of the most important task in river engineering. Even today, numerical models of sediment transport processes are confronted with some difficulties, often of conceptual nature. One of these difficulties is the simulation of non-uniform sediment transport in non-equilibrium situations, which requires the characterization of the ability of the alluvial system to immediately overcome the variations of the sediment boundary conditions. In this work a 1-D numerical model, which includes a new expression of the so-called “adaptation coefficient”, has been applied to test its capability to simulate the transient bed p…

Dip Phenomenon in High-Curved Turbulent Flows and Application of Entropy Theory

2018

The estimation of velocity profile in turbulent open channels is a difficult task due to the significant effects of the secondary flow. The present paper investigates the mechanism of the velocity-dip phenomenon, whereby the location of the maximum velocity appears to be below the free surface. Previous studies conducted in straight channels relate the mechanism of the velocity-dip phenomenon to secondary flow induced by anisotropy of turbulence. This work focuses on high-curved channels where the secondary motion, which is also induced by the channel’s curvature, evolves along the bend. The width-to-depth ratio, B/h, is one of the most important parameters that are affecting the secondary …

Examen de las dinámicas socio-ecológicas en el valle medio del Xuquer (Valencia) desde el Paleolítico Medio hasta el Calcolítico

2017

En paisajes intensamente modificados por terrazas agrícolas y otros usos modernos del suelo, el patrón espacial y temporal del poblamiento prehistórico puede ser difícil de detectar usando métodos de prospección arqueológica tradicionales orientados a la localización de yacimientos part iculares. El abancalamiento del territorio para su explotación agrícola es norma común en el área de trabajo, por lo que es necesario examinar el paisaje en su conjunto, en lugar de intentar localiza r zonas concretas de actividad ant rópica prehistórica. Para superar estos desafíos, se ha empleado una estrategia estratificada, seleccionando aleato ria me nte las parcelas a prospectar, para examinar las diná…

How could hydro-climatic conditions evolve in the long term in West Africa? The case study of the Bani River catchment

2011

International audience; This paper assesses the future variability of water resources in the long term over a large Sudano- Sahelian catchment in West Africa. Flow simulations were performed with a daily conceptual model. The climate models HadCM3 and MPI-M (based on SRES-A2) were used to provide future climate scenarios over the catchment. Outputs from these models were used to generate daily rainfall and temperature series for the 21st century according to: (i) application of the unbias and delta methods, and (ii) spatial and temporal downscaling. A temperature-based formula was used to calculate present and future potential evapotranspiration (PE). The daily rainfall and PE series were i…

Dissolved silica in the Garonne River waters : changes in the weathering dynamics

2000

The major ion chemistry of the Garonne River is indicative of seasonal variations in the weathering dynamics of the drainage basin. Using the geochemical model MEGA for calculation of the contribution of atmospheric CO2 to the total bicarbonate fluxes exported by the Garonne River allows estimations of the concentrations of the major dissolved elements that originate from silicate- and carbonate-rock weathering. The molecular ratio SiO2/Al2O3 was calculated for the 1989–1992 period to identify the main type of weathering in the Garonne River, and montmorillonite was shown to be the major mineral occurring in the weathering products. The seasonal variations of the SiO2/Al2O3 ratio also showe…

Exposure of benthic microbial communities to pharmaceuticals and resulting adaptation including tolerance, biodegradation and antibiotic resistance: …

2022

International audience; Since the early 1920’s, pharmaceuticals, including antibiotics, have been massively producedand consumed for the benefit of both human and animal health. Pharmaceuticals residues havethen reached the aquatic environment through diffuse and point (wastewater) sources. Amongthe pharmaceutical residues, the ubiquitous presence of antibiotics could exert a selectivepressure on microbial communities leading to the acquisition and dissemination of antibioticresistance in the environment.We present here the synthesis of recent research projects (e.g. PANDORE, Antibio-tools,Antibiotox, PharmaTox...) investigating the dissemination of pharmaceuticals, includingantibiotics, in…

The movement of People in the upper Seine basin during the Roman period (1st century BCE – 5th century CE): infrastructures and written testimony.

2021

Archaeological and historical data to do with the movement of populations and goods in the Seine catchment area have not yet been overviewed for the Roman period. The Arkéaube conference offers an opportunity to present research on this subject. We can observe that, during the Roman period, the Seine valley was a major thoroughfare located downstream from the confluence of the Seine and the Yonne. Upstream, the Yonne gradually replaced the Petite Seine as a major route across the south-east of the Paris Basin.

Inland harbours in Central Europe: Nodes between Northern Europe and the Mediterranean Sea

2019

Inland navigation on French rivers

2020

DOI: https://doi.org/10.22032/dbt.40680 (pdf), https://doi.org/10.22032/dbt.40683 (csv), https://doi.org/10.22032/dbt.40682 (excel).; International audience

Rivero Jean

2007

Entrée de dictionnaire; Dictionnaire historique des juristes français XIIe-XXe siècles