1,440 research outputs found

    Rainfall thresholds derivation for warning pluvial flooding risk in urbanised areas

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    Aim of this work is the development of an operational tool for pluvial flooding warning in an urban area based on off-line rainfall thresholds derived by coupling a rainfall-runoff modelling and a hydraulic routing. The critical conditions considered for issue flood warnings were not only based on the water stage, but also on the extension of the flooded area. Further, a risk assessment framework for quantifying the reliability of the rainfall thresholds has been included; rainfall thresholds used in pluvial flooding warning should be influenced by the uncertainties in the rainfall characteristics (i.e. rainfall duration, depth and storm pattern). This risk assessment framework incorporates the correlated multivariate Monte Carlo simulation method, an hydraulic model for the simulation of rainfall excess propagation over surface urban drainage structures, i.e. streets and pathways. Thresholds rainfall are defined using a number of inundation criteria, to analyze the change in the rainfall threshold due to various definitions of inundation. Starting from estimated water stages and flooded area from inundation simulation rainfall thresholds can be obtained according a specific inundation criterion, including, together, a critical water depth and a critical flooding area. Finally, the second phase concerns the imminence of a possible hydrological risk by comparing the time when cumulative rainfall and rainfall thresholds meet to each other. The developed procedure has been applied to the real case study of Mondello catchment in Palermo (Italy)

    Estimation of synthetic flood design hydrographs using a distributed rainfall–runoff model coupled with a copula-based single storm rainfall generator

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    In this paper a procedure to derive synthetic flood design hydrographs (SFDH) using a bivariate representation of rainfall forcing (rainfall duration and intensity) via copulas, which describes and models the correlation between two variables independently of the marginal laws involved, coupled with a distributed rainfall–runoff model, is presented. Rainfall–runoff modelling (R–R modelling) for estimating the hydrological response at the outlet of a catchment was performed by using a conceptual fully distributed procedure based on the Soil Conservation Service – Curve Number method as an excess rainfall model and on a distributed unit hydrograph with climatic dependencies for the flow routing. Travel time computation, based on the distributed unit hydrograph definition, was performed by implementing a procedure based on flow paths, determined from a digital elevation model (DEM) and roughness parameters obtained from distributed geographical information. In order to estimate the primary return period of the SFDH, which provides the probability of occurrence of a hydrograph flood, peaks and flow volumes obtained through R–R modelling were treated statistically using copulas. Finally, the shapes of hydrographs have been generated on the basis of historically significant flood events, via cluster analysis. <br><br> An application of the procedure described above has been carried out and results presented for the case study of the Imera catchment in Sicily, Italy

    Analysis of the Effects of Reservoir Operating Scenarios on Downstream Flood Damage Risk Using an Integrated Monte Carlo Modelling Approach

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    The aim of this study is to analyse the effects of reservoir operating scenarios, for flood damage evaluation downstream of a dam, using a Monte Carlo bivariate modelling chain. The proposed methodology involves a stochastic procedure to calculate flood hydrographs and the evaluation of the consequent flood inundation area by applying a 2D hydraulic model. These results are used to estimate the inundation risk and, as consequence, the relative damage evaluation under different water level conditions in an upstream reservoir. The modelling chain can be summarized as follows: single synthetic stochastic rainfall event generation by using a Monte Carlo procedure through a bivariate copulas analysis; synthetic bivariate stochastic inflow hydrograph derivation by using a conceptual fully distributed model starting from synthetic hyetographs above the derived; flood hydrographs routing through the reservoir taking in an account of the initial level in the reservoir; flood inundation mapping by applying a 2D hydraulic simulation and damage evaluation through the use of appropriate depth-damage curves. This allowed for the evaluation of the influence of initial water level on flood risk scenarios. The procedure was applied to the case study of the floodplain downstream from the Castello reservoir, within the Magazzolo river catchment, located in the southwestern part of Sicily (Italy)

    Efecto de la fertilización sobre la producción de un fruto forestal comestible: el piñón de pino piñonero (Pinus pinea L.) en Andalucía Occidental

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    The pine nut from the stone pine (Pinus pinea L.) is the most important edible fruit in mediterranean forests. Despite this fact, there is a lack of knowledge regarding the application of agronomy techniques in stands of this species to increase pine nut production. Our study focuses on the effect of mineral fertilization on cone production and size, which in turn, are closely related to nut yield and quality. Cone production and quality was analysed in a randomized experiment installed in south west Spain, comparing the effect of different doses of lime superphosphate, dolomite and potassium. A significant short term increase in cone production and quality exists as a consequence of fertilization, especially in those treatments involving the addition of larger quantity of dolomite. Nevertheless, effect of mineral fertilization on cone yield and quality was lower than expected, so further increments might be achieved through nitrogenous and organic fertilizations to improve soil structure in these sandy soils.El pi&ntilde;&oacute;n de Pinus pinea L. es el fruto forestal comestible m&aacute;s importante en los bosques mediterr&aacute;neos. Pese a esto, existe una falta de conocimiento cient&iacute;fico acerca de la aplicaci&oacute;n de pr&aacute;cticas agron&oacute;micas sobre las masas forestales de la especie al objeto de mejorar la producci&oacute;n de pi&ntilde;&oacute;n. Nuestro trabajo se centra en el an&aacute;lisis del efecto de la fertilizaci&oacute;n mineral sobre la producci&oacute;n y el tama&ntilde;o de las pi&ntilde;as, variables muy relacionadas con la cantidad y calidad de pi&ntilde;&oacute;n. Entre 1993-1999 se realiz&oacute; el seguimiento de la producci&oacute;n y la calidad de la pi&ntilde;a en un experimente aleatorizado instalado en el SO de Espa&ntilde;a, donde se comparaban diferentes dosis de superfosfato de cal, dolomita y cloruro pot&aacute;sico. Se ha detectado una respuesta positiva a la fertilizaci&oacute;n en la cantidad y calidad de las pi&ntilde;as producidas, especialmente en los tratamientos que planteaban la incorporaci&oacute;n de una mayor cantidad de dolomita. El efecto de la fertilizaci&oacute;n mineral sobre la cantidad y calidad de pi&ntilde;a ha sido menor que el esperado, por lo que futuros trabajos deben plantear la necesidad de incorporar fertilizantes nitrogenados y materia org&aacute;nica para mejorar la estructura en estos suelos arenosos

    DERIVAZIONE DI IDROGRAMMI DI PIENA ATTRAVERSO L\u2019ACCOPPIAMENTO DI MODELLI STOCASTICI BIVARIATI DELLE PRECIPITAZIONI E E MODELLI AFFLUSSI - DEFLUSSI DISTRIBUTI

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    In questo studio viene presentata una procedura di tipo Monte Carlo per la derivazione delle curve di frequenza delle portate al colmo e dei volumi corrispondenti basata sull\u2019accoppiamento di un modello di generazione delle forzanti pluviometriche tramite copule e un modello di trasformazione afflussideflussi di tipo distribuito. Tale procedura \ue8 stata applicata ad un caso di studio siciliano; i risultati ottenuti hanno mostrato la bont\ue0 del modello a riprodurre le statistiche complesse delle grandezze idrologiche a fronte di un basso numero di parametri modellistici e di un ridotto sforzo computazionale

    DWT-based Method for Partial Discharge Pattern Recognition

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    The new proposed method of pattern recognition is based on the application of Multiresolution Signal Decomposition (MSD) technique of wavelet transform. This technique has shown interesting properties in capturing the embedded horizontal, vertical and diagonal variations within an image obtained from the PD pattern in a separable form. This feature has been exploited to identify in the PD patterns MSD, relative at various family of PD sources, some detail images typical of a single discharge phenomenon. The classification of a generic PD phenomenon is feasible through a comparison between its detail images and the detail images typical of a single discharge phenomenon. Tests have been performed on specimens having single defects. The obtained results prove that the proposed improved classification methods is quite efficient and accurate. [DOI: 10.1685 / CSC06133] About DO
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