Search results for "Floodplain"
showing 10 items of 37 documents
Assessment of channel changes in a Mediterranean ephemeral stream since the early twentieth century. The Rambla de Cervera, eastern Spain
2013
An analysis of morphological changes during the last six decades is presented for a 16.5-km reach of the Rambla de Cervera, a Mediterranean ephemeral stream located in eastern Spain. Channel changes were analysed through a range of techniques, specifically the analysis of aerial photographs with geographical information systems (GIS) and comparison of topographic surveys. The gravel channel underwent a general decline over the study period, losing width (68.5%) and surface area (45.7%). Incision ocurred along the entire study reach at an average depth of 3.5 m. Natural and human-induced factors producing contradictory effects are considered responsible for changes in the Rambla de Cervera
Mapping temporally-variable exposure to flooding in small Mediterranean basins using land-use indicators
2011
Abstract This article deals with mapping exposure (or external vulnerability) to flood risk in two typical Mediterranean ephemeral streams: the Barranco de Carraixet and the Rambla de Poyo. The floodplains of both streams are within the metropolitan area of the city of Valencia (Spain’s third largest city). Following the Mediterranean model, they are very fertile areas (with intense periurban and highly productive agriculture) which have recently absorbed the great urban expansion of the metropolis. Hydrologically these basins remain dry for most of the year, but become particularly dangerous during flash-flood events. They generate a risk pattern highly dependent on exposure since, in gene…
High Prevalence of Human-Associated Escherichia coli in Wetlands Located in Eastern France
2020
International audience; Escherichia coli that are present in the rivers are mostly brought by human and animal feces. Contamination occurs mostly through wastewater treatment plant (WWTP) outflows and field amendment with sewage sludge or manure. However, the survival of these isolates in river-associated wetlands remains unknown. Here, we assessed E. coli population structure in low-anthropized wetlands located along three floodplains to identify the major source of contamination of wetlands, whose functioning is different from the rivers. We retrieved 179 E. coli in water samples collected monthly from 19 sites located in eastern France over 1 year. Phylogroups B1 and B2 were dominant in …
Geomorphological evolution of the River Loukkos estuary around the Phoenician city of Lixus on the Atlantic Littoral of Morocco
2009
The ancient city of Lixus, today situated on a hill on the right bank of the River Loukkos, 4km from the coast, was founded on the shore of a brackish lagoon that was sheltered from Atlantic storms. This geographical context provided the city with one of the best Phoenician harbors and abundant fishing resources, and allowed access to the Gharb cattle farming resources and cereal production systems. In this study, the historical evolution of the Loukkos estuarine environment is reconstructed through geomorphological and sedimentological analyses, combined with cartographic, archaeological, and geographical data. The outcomes reveal the progressive infilling of the estuarine lagoon of Lixus …
Elaboración de cartografía de zonas inundables : aplicación al llano de inundación del río Arga (Navarra)
2000
La inundación es el riesgo natural de mayor impacto social y económico, la persistencia del problema a pesar de los continuos avances tecnológicos pone de manifiesto la necesidad de estudiar más detalladamente el comportamiento de las áreas inundables y elaborar una cartografía de riesgo que contribuya a un uso más racional del espacio. Este trabajo presenta el proceso de elaboración del mapa de riesgo del llano de inundación del río Arga (Navarra) en los municipios de Falces, Peralta y Funes. La demarcación de áreas inundables para diferentes valores de caudal máximo se llevó a cabo mediante la combinación de métodos estadísticos, hidrológicos, hidráulicos y geomorfológicos. Algunos proces…
Mercury Speciation in Floodplain Soils and Sediments along a Contaminated River Transect
1998
A novel mercury-specific sequential extraction procedure (SEP) for the assessment of mercury (Hg) speciation in soils and sediments, with emphasis on studying the interaction between Hg and organic matter (OM), was developed and tested. It was applied to determine Hg speciation in floodplain topsoils and surface sediments along the Hg-contaminated part of the river Elbe, and to simultaneously derive some information on the (re)mobilization potentials for Hg from these matrices. The majority of the total Hg in the ecosystem today is bound in the floodplains, which also still geographically reflect the historic emission record. Most of the Hg in both matrices is bound strongly to OM, suggesti…
The Assessment of Heavy Metal Contamination of the Cultivated Soils in the Odra River Floodplain
2021
Abstract The aim of the study was to assess the contamination of selected heavy metals in cultivated soils of the Odra river floodplain. The heavy metals Mn, Fe, Cu, Zn, Ni, Cd and Pb were determined in soil samples collected in the autumn of 2020 - after the vegetation period of plants from designated measurement points. Concentrations of the analytes were measured using an atomic absorption spectrometer (F-ASA). A comparison was made between concentrations of heavy metals in soil samples collected from areas flooded in 1997 and from areas flooded as a result of rainfall, snowmelt and winter floods. The results of the studies were compared with the data for soils taken from non-flooded are…
The FLO Diffusive 1D-2D Model for Simulation of River Flooding
2016
An integrated 1D-2D model for the solution of the diffusive approximation of the shallow water equations, named FLO, is proposed in the present paper. Governing equations are solved using the MArching in Space and Time (MAST) approach. The 2D floodplain domain is discretized using a triangular mesh, and standard river sections are used for modeling 1D flow inside the section width occurring with low or standard discharges. 1D elements, inside the 1D domain, are quadrilaterals bounded by the trace of two consecutive sections and by the sides connecting their extreme points. The water level is assumed to vary linearly inside each quadrilateral along the flow direction, but to remain constant …
Phytoplankton in the physical environment: beyond nutrients, at the end, there is some light
2009
This article summarizes the outcomes of the 15th Workshop of the International Association for Phytoplankton Taxonomy and Ecology. Four major issues dealing with the role of physical factors in phytoplankton ecology were addressed in the articles of this special volume: global change and its likely impacts on phytoplankton, the role of physical factors in the autecology of particular species, impacts on the inocula for the following years, and the role of light in shaping phytoplankton dynamics. Case studies from different types of aquatic environments (rivers, deep and shallow lakes, floodplain lakes, wetlands, oxbows, and even the deep ocean) and from diverse geographical locations (not o…
The discovery of a Mycenaean-type tholos tomb in the Bronze Age necropolis of the Gazzi buried floodplain (Messina, Southern Italy): new geological a…
2019
This paper deals with a monument that is, up to this date, unique in Sicily and in the Italian peninsula: the Mycenaean-type tholos tomb of the Gazzi necropolis in Messina. A recent excavation in the alluvial deposits revealed extensive traces of a funerary area with a tholos tomb and several enchytrismos tombs with skeletal remains, presumably dated back to the end of the Early or the initial stage of the Middle(?) Bronze Age. The present multi-disciplinary investigation has been developed to analyse new data related to sediments, building stones and skeletal remains of this funerary area. The stratigraphic succession hosting the necropolis was formed by overbank sediments deposited on the…