1,720,994 research outputs found
Derivation of flood frequency curves in poorly gauged Mediterranean catchments using a simple stochastic hydrological rainfall-runoff model
No full textIn this paper a Monte Carlo procedure for deriving frequency distributions of peak flows using a semi-distributed stochastic rainfall-runoff model is presented. The rainfall-runoff model here used is very simple one, with a limited number of parameters and practically does not require any calibration, resulting in a robust tool for those catchments which are partially or poorly gauged.The procedure is based on three modules: a stochastic rainfall generator module, a hydrologic loss module and a flood routing module. In the rainfall generator module the rainfall storm, i.e. the maximum rainfall depth for a fixed duration, is assumed to follow the two components extreme value (TCEV) distribution whose parameters have been estimated at regional scale for Sicily. The catchment response has been modelled by using the Soil Conservation Service-Curve Number (SCS-CN) method, in a semi-distributed form, for the transformation of total rainfall to effective rainfall and simple form of IUH for the flood routing. Here, SCS-CN method is implemented in probabilistic form with respect to prior-to-storm conditions, allowing to relax the classical iso-frequency assumption between rainfall and peak flow. The procedure is tested on six practical case studies where synthetic FFC (flood frequency curve) were obtained starting from model variables distributions by simulating 5000 flood events combining 5000 values of total rainfall depth for the storm duration and AMC (antecedent moisture conditions) conditions. The application of this procedure showed how Monte Carlo simulation technique can reproduce the observed flood frequency curves with reasonable accuracy over a wide range of return periods using a simple and parsimonious approach, limited data input and without any calibration of the rainfall-runoff model
A Regional Methodology for Deriving Flood Frequency Curves (FFC) in Partially Gauged Catchments with Uncertain Knowledge of Soil Moisture Conditions
No full textMappatura probabilistica della pericolosità idraulica: analisi dell’incertezza legata all’utilizzo di un approccio bivariato per l’analisi di frequenza delle portate di piena
No full textUncertain Characterization of Flood Hazard Using Bivariate Analysis Based on Copulas
Full text linkThis study presents a methodology to derive probabilistic flood hazard map in flood prone areas taking into account uncertainties in the definition of design-hydrographs. Particularly, we present an innovative approach to obtain probabilistic inundation and flood hazard maps where hydrological input (synthetic flood design event) to a 2D hydraulic model has been defined by generating flood peak discharges and volumes from a bivariate statistical analysis, through the use of copulas. This study also aims to quantify the contribution of boundary conditions
uncertainty in order to explore the impact of this uncertainty on probabilistic flood hazard mapping. The uncertainty of extreme flood events is considered in terms of different possible combinations of peak discharge and flood volume given by the copula. Further, we analyzed the role of a multivariate probability hydrological analysis on inundation and flood hazard maps highlighting the differences between deterministic and probabilistic approaches. The methodology has been applied to a study area located in Sicily that was subject to several flooding events in
the past
Analisi di incertezza nella risposta quali-quantitativa a scala giornaliera di un bacino naturale
No full textWATER RESOURCES ASSESSMENT UNDER WATER SCARCITY SCENARIOS
No full textcuratela del testo "WATER RESOURCES ASSESSMENT UNDER WATER SCARCITY SCENARIOS
Specific calibration and predictive uncertainty evaluation strategies for flood propagation models
No full textHydraulic models are an essential tool in many fields, e.g. civil engineering, flood hazard and risk assessments, evaluation of flood control measures, etc. Nowadays there are many models of different complexity regarding the mathematical foundation and spatial dimensions available, and most of them are comparatively easy to operate due to sophisticated tools for model setup and control. However, the calibration of these models is still underdeveloped in contrast to other models like e.g. hydrological models or models used in ecosystem analysis. This has basically two reasons: First, the lack of relevant data against the models can be calibrated, because flood events are very rarely monitored due to the disturbances inflicted by them and the lack of appropriate measuring equipment. Secondly, especially the two-dimensional models are computationally very demanding and therefore the use of available sophisticated automatic calibration procedures is restricted in many cases. This study takes a well documented flood event in August 2002 at the Mulde river in Germany as an example and investigates the most appropriate calibration strategy for a full 2D hyperbolic finite element model. The model independent optimiser PEST, that gives the possibility of automatic calibrations, is used. The aim is to minimize computational calibration time in relation to the required output of the model. Thus the assessment of the influence of the number and spatial distribution of observed maximum inundation depths on the calibration results and the predictive uncertainty of different optimisations are carried out
Applicability of hydrological similarities measures based on linkage between rain and flood regime for regional flood frequency analysis in Mediterranean catchment.
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