Search results for "Catchment"
showing 10 items of 75 documents
Influence of surface roughness in hydrological response of semiarid catchments
2005
Abstract Here, an investigation has been carried out in order to understand the influence of the surface roughness in the definition of the hydrological response of semiarid catchments. Following a previous study of one of the authors, a modified version of TOPMODEL is used, in which the convolution routing procedure has been extended to the hillslopes by specifying the routing velocity for each pixel of the watershed. These velocities have been linked to the watershed land use through the different surface roughness whose coefficients has been derived on the basis of Engman's table. In this paper, roughness coefficient distributions are expressed as function of a unique value treated as a …
Stream‐Discharge Surges Generated by Groundwater Flow
2019
International audience
Post-fire hydrological response and suspended sediment transport of a terraced Mediterranean catchment
2017
In July 2013, a wildfire severely affected the western part of the island of Mallorca (Spain). During the first three post-fire hydrological years, when the window of disturbance tends to be more open, the hydrological and sediment delivery processes and dynamics were assessed in a representative catchment intensively shaped by terracing that covered 37% of its surface area. A nested approach was applied with two gauging stations (covering 1.2 km2 and 4.8 km2) built in September 2013 that took continuous measurements of rainfall, water and sediment yield. Average Suspended Sediment Concentration (1,503 mg l-1) and the maximum peak (33,618 mg l-1) were two orders of magnitude higher than tho…
Exploring calibration strategies of the SEDD model in two olive orchard catchments
2017
To optimize soil conservation strategies in catchments, it is required an accurate diagnosis of the areas contributing to soil erosion by using models such as SEDD (Sediment Delivery Distributed model). In this study, different calibration strategies of the SEDD model were explored to adapt its use in two olive catchments with different environmental features and managements. A data series of rainfall–runoff–sediment load, collected in the catchments for 6 years was used: i) to evaluate calibration strategies for different management and flow conditions through the analysis of the C and R factors, and ii) to describe the temporal patterns of sediment delivery ratio (SDR) at the event and an…
Improving transferability strategies for debris flow susceptibility assessment: Application to the Saponara and Itala catchments (Messina, Italy)
2017
Abstract Debris flows can be described as rapid gravity-induced mass movements controlled by topography that are usually triggered as a consequence of storm rainfalls. One of the problems when dealing with debris flow recognition is that the eroded surface is usually very shallow and it can be masked by vegetation or fast weathering as early as one-two years after a landslide has occurred. For this reason, even areas that are highly susceptible to debris flow might suffer of a lack of reliable landslide inventories. However, these inventories are necessary for susceptibility assessment. Model transferability, which is based on calibrating a susceptibility model in a training area in order t…
Effects of agricultural drainage systems on sediment connectivity in a small Mediterranean lowland catchment
2018
Traditional drainage systems combining man-made channels and subsurface tile drains have been used since Roman times to control water excess in Mediterranean lowland regions, favouring adequate soil water regime for agriculture purposes. However, mechanization of agriculture, abandonment or land use changes lead to a progressive deterioration of these drains in the last decades. The effects of these structures on hydrological and sediment dynamics have been previously analyzed in a small Mediterranean lowland catchment (Can Revull, Mallorca, Spain, 1.4 km2) by establishing an integrated sediment budget with a multi-technique approach. Moreover, the recent advances in morphometric techniques…
Treated Incidence of Psychotic Disorders in the Multinational EU-GEI Study
2018
Importance: Psychotic disorders contribute significantly to the global disease burden, yet the latest international incidence study of psychotic disorders was conducted in the 1980s. Objectives: To estimate the incidence of psychotic disorders using comparable methods across 17 catchment areas in 6 countries and to examine the variance between catchment areas by putative environmental risk factors. Design, Setting, and Participants: An international multisite incidence study (the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions) was conducted from May 1, 2010, to April 1, 2015, among 2774 individuals from England (2 catchment areas), France (3 catch…
The point prevalence of otitis media with eVusion among primary school children in Western Sicily
2009
The objective of this study is to identify the prevalence of otitis media with effusion (OME) in primary school children and to value the possible predisposing factors focusing on relationship between allergy and OME in Western Sicily. 2,097 children attending primary school were screened from September 2006 to June 2007 in Sciacca. Children underwent pneumatic otoscopy, skin tests, tympanogram and acoustic reflex tests. Audiogram was performed if the child had a type B or a type C tympanogram. The criteria for diagnosis of OME were: documented persistent middle ear effusion by otoscopic examination for a minimum of 3 months, presence of B or C tympanogram, absence of ipsilateral acoustic r…
An epidemiological study of dental agenesis in a primary health area in Spain : estimated prevalence and associated factors
2010
Objectives: To evaluate the prevalence of dental agenesis and its possible association with other developmental dental anomalies and systemic entities. Setting and Sample Population: Descriptive transversal study, for which 1518 clinical records, of patients visited by the Odontological Service of the Primary Health Centre of Cassà de la Selva (Girona-Spain) between December 2002 and February 2006 were reviewed. The data were recorded in relation to the oral and dental anomalies and the associated systemic entities, between the ones referred as concomitant in literature. Results: Values of 9.48% (7.25% excluding the third molars) for dental agenesis and 0.39% for oligodontia were obtained. …
Co-occurrence of developmental delays in a screening study of 4-year-old Finnish children
2004
The aim of this population study was to examine the severity and prevalence of co-occurring developmental delays in 4-year-old children, the rate of overlapping problems, and sex differences. A sample of 434 children (196 males, 238 females; mean age 4 years 3 months, SD 1 month) were administered the 'Lene' test: a comprehensive neurodevelopmental screening test. Results suggest that co-occurrence of attention-behavioural, motor-perceptual, and language delays occurring in school-aged children could already be detected at the age of 4 years. Isolated delays were usually mild, but co-occurring difficulties were mostly moderate or severe. Overlap between developmental delays depended on the …