Two-Dimensional Hydraulic Modeling and Analysis of Morphological Changes in the Palancia River (Spain) During a Severe Flood Event on October 2000

This paper analyzes the possibilities that mathematical models offer to reconstruct flood events, and to predict their erosional and sedimentary effects. To that end, the severe flood event of October 2000 of the Palancia River (Valencia, Spain) is assessed. The hydraulic reconstruction was performed with the software GUAD 2D, a two-dimensional mathematical simulation model for shallow water conditions. The results obtained from the mathematical model and the hydraulic-sedimentological analysis were compared with the flood-related features mapped by means of geomorphologic photo-interpretation and field observations. This comparative study illustrates that these models constitute a powerful…

Cambio tecnológico, privatización y recuperación de la autogestión comunitaria del riego. El caso de Senyera (València)

[ES] Los procesos de cambio de tecnología del riego están facilitando la penetración silenciosa de la empresa privada en los sistemas de gestión colectiva del riego en numerosos lugares de España y otros países mediterráneos. Este artículo analiza este fenómeno a partir del caso de estudio de Senyera (València), siguiendo la privatización, la disputa y la posterior recolectivización de la gestión por parte de los usuarios del riego. El trabajo muestra como la privatización menoscaba la autonomía de los agricultores y eleva los costes de gestión en un contexto de escasa transparencia. También revela la capacidad de los regantes para reelaborar su pasada acción colectiva, dando lugar a una nu…

Variabilidad espacial de los cambios de cauce en una rambla mediterránea en las seis últimas décadas (1946-2006)

An analysis of morphological changes during the last six decades is presented for the Rambla de Cervera, a Mediterranean ephemeral stream located in the eastern sector of the Iberian Mountain Range. The studied channel (16.5 km) has two contrasted sectors: a horst confined sector (5.5 km) and a graben sector (11 km). Channel changes were analysed through the analysis of aerial photographs, with geographical information systems (GIS) and comparison of topographic surveys made with a GPS-RTK. Between 1946 and 2006 the Rambla de Cervera, underwent channel adjustments comparable to those observed in other Mediterranean rivers. The gravel channel markedly narrowed, losing width (68.5%) and chann…

Channel forms and vegetation adjustment to damming in a Mediterranean gravel‐bed river (Serpis River, Spain)

Assessment of channel changes in a Mediterranean ephemeral stream since the early twentieth century. The Rambla de Cervera, eastern Spain

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

La laguna opaca. Gestión y gobernanza del agua en l’Albufera de València (España)

International audience; The Albufera de Valencia is a complex anthropogenic waterscape, constructed by different social groups over centuries. Today water management in the protected wetland remains opaque, much like the water in the eutrophic lagoon. Four major organiza-tions manage this natural heritage, which remains torn between nature conservation and rice growing, in a jigsaw of overlap-ping jurisdictions and crisscrossed visions. Water management in this socioecological-system is complex and contested, and takes place within a changing scenario due to recent variations in the water quality and quantity budgets. This paper analyses this changing socio-ecological system based on interv…

Flood processes and morphological changes in aggradational ephemeral rivers. Reconstruction of the October 1957 flood in the Rambla Castellarda (Spain)

During the latter half of the twentieth century, Mediterranean ephemeral rivers underwent a profound metamorphosis. Fluvial adjustment processes narrowed the channels, simplified their planform pattern and notably reduced sediment availability. Today, this makes it extremely difficult to analyse the behaviour of this type of river in former aggradational contexts, such as those seen at the middle part of the twentieth century. For this reason, this paper addresses a reconstruction and analysis of the 1957 flood that occurred in the Rambla Castellarda, a tributary of the Turia river. The research is based, among other sources, on a series of extraordinary, high-precision aerial photographs c…

Channel forms recovery in an ephemeral river after gravel mining (Palancia River, Eastern Spain)

[EN] During the 1970s, the Palancia River was intensively affected by gravel mining instream. This activity completely destroyed the fluvial forms, devastating the original wandering pattern. At the end of the 1980s, gravel mining ceased and the river started a process of recovery, only altered by several clearing operations. The aim of this work is to describe these processes of change, analyzing the river's morphosedimentary conditions through a GIS analysis of aerial photographs previous to, simultaneous with, and subsequent to the intense gravel mining activity. Results explain the current difficulties of some ephemeral rivers to recover their original forms, because of the sediment and…