This article deals with flood events in Mediterranean ephemeral streams typical of the Valencia Ž region. The combination of the basin physical characteristics steep slopes, sparse vegetation, thin . soils and permeable rock and intense, heavy and irregularly distributed rain, generates flash floods. Runoff generation is sudden, giving rise to flash floods with sharp, narrow hydrographs with short time lags. The high amount of runoff is, nevertheless, only a small fraction of the total rainfall, since the characteristics of the river basins are such that infiltration of large amounts of water occurs. Using daily hydrological data from the Rambla de la Viuda basin and 5-min data from both the Barranc del Carraixet and the Rambla de Poyo basins, the rainfall-runoff processes have been analysed during flood events in these ephemeral streams. q

(2012). Six decades of changes in the riparian corridor of a Mediterranean river: A synthetic analysis based on historical data sources. Ecohydrology, 6 (4): 536¿553. doi:10.1002/eco.1330.1 This is a pre-copyedited, author-produced PDF version following peer review of the article: Garófano-Gómez, V., F. Martínez-Capel, W. Bertoldi, A. Gurnell, J. Estornell, F. Segura-Beltrán. 2013 ABSTRACTRiparian corridors in semi-arid Mediterranean environments are ecosystems of high biodiversity and complexity. However, they are threatened because of high levels of human intervention. River damming and related flow manipulation is considered as one of the most prominent human impacts on riparian corridors. This study combines historical time series information on river flows and their human manipulation, historical aerial images depicting changes in riparian land cover and ground observations of the species -age composition and morphology of the riparian corridor of a Mediterranean river (the Mijares River, Eastern Spain) over the last 60 years. In this sense, we explored how to integrate information from a wide variety of data sources, and we extracted a variety of indices and undertook analyses that identified and summarized spatio-temporal changes in riparian structure and in the driving flow processes.Results revealed an increase in the cover and density of woody vegetation and a decrease in bare sediment areas (essential for recruitment of riparian pioneer species), with a synchronous reduction in the complexity of the riparian corridor of the middle reaches of the Mijares River. These vegetation changes have accompanied a decrease in the magnitude and variability of river flows over the last six decades, with higher severity since dam closure. This study illustrates the effectiveness of combining disparate historical data sources and the effectiveness of processing these sources to extract informative metrics that can improve the understanding and management of riparian systems.

This paper analyses the River Girona (Spain) flash flood, occurred the 12th of October 2007, combining hydrological and hydraulic modeling with geomorphologic mapping and post-flood survey information. This research aims to reproduce the flood event in order to understand and decipher the flood processes and dynamics on a system of *Manuscript Click here to download Manuscript: JoH_Girona_Flashflood.docx Click here to view linked References overlapped prograding alluvial fans. The hydrological model TETIS was used to characterize the shape and dimension of the October 2007 River Girona hydrograph. Subsequently, the flood event was reproduced using the free surface flow module of the model RiverFlow2D. The combination of hydrological and hydraulic models was validated using post-flood surveys defining maximum flooded area and flood depths. Then, simulations with different peak discharges were carried out to estimate the hydrogeomorphologic response of the Girona River floodplain, through the identification of the activation thresholds in different geomorphic elements. Results showed that the unit peak discharge of the October 2007 flood event was among the largest ever recorded in the area, according to the existing literature. Likewise, the hydraulic model showed a good performance (Fit A = 76 %, RMSE = 0.65 m and NSE = 0.6), despite the complexity of the case, an ephemeral and ungauged river. The model simulation revealed the existence of a geo-chronological activation pattern of palaeochannels and alluvial fans, which was altered by the presence of a tectonic depression and bridges construction.This multidisciplinary approach proved to be a useful strategy for understanding flash flood processes in ungauged catchments. It allowed understanding the mechanisms governing floods in alluvial fans systems and it represented a solid contribution for early warning plans and risk mitigation policies.

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