1,720,990 research outputs found
Stima delle prestazioni di una vasca di laminazione: confronto tra simulazioni continue e metodi analitico-probabilistici
Full text linkI criteri di dimensionamento delle vasche di laminazione elaborati secondo
l’approccio dell’evento critico presentano alcuni limiti. Il più rilevante di essi
risiede nella difficoltà di tenere in considerazione la naturale variabilità delle piene
e la loro successione temporale. Le simulazioni di lungo periodo ed i metodi
analitico-probabilistici invece possono ovviare efficacemente a questo
inconveniente, pervenendo così a stime dei tempi di ritorno delle portate al colmo
concettualmente corrette. In riferimento ad un caso di studio, rappresentato da un
dispositivo d’invaso progettato per proteggere la città di Brescia dalle piene del
torrente Garza, sono state ricavate mediante questi due diversi approcci le
distribuzioni di frequenza delle portate di picco prodotte dal bacino naturale e
quelle laminate. Il loro confronto ha evidenziato alcuni limiti del secondo metodo,
che tuttavia sembra meritevole di ulteriore approfondimento
Analisi dei criteri di gestione delle vasche di prima pioggia mediante metodi innovativi
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Multivariate statistical analysis of flood variables by copulas: two italian case studies
No full textMultivariate statistics are important to determine the flood hydrograph for the design of hydraulic structures and for the hydraulic risk assessment. In the last decade, the copula approach has been investigated in hydrological practice to assess the design flood hydrograph in terms of flood peak, volume and duration. In this paper, the copula approach is exploited to perform pair analyses of these three random variables for two Italian watersheds, in the Apennine and the Alps respectively. The criterion to separate continuous flow series into independent events is discussed along with its implications on the dependence structure. The goodness-of-fits of the proposed copulas are then assessed by non-parametric tests. Marginal distributions to derive joint distributions are briefly suggested. The possibility of generating flood events according to the proposed model and potential applications to hydraulic structure design and flood management are finally examined
Deriving a practical analytical-probabilistic method to size flood routing reservoirs
No full textIn the engineering practice routing reservoir sizing is commonly performed by using the design storm method, although its effectiveness has been debated for a long time. Conversely, continuous simulations and direct statistical analyses of recorded hydrographs are considered more reliable and comprehensive, but are indeed complex or seldom practicable. In this paper a handier tool is provided by the analytical-probabilistic approach to construct probability functions of peak discharges issuing from natural watersheds or routed through on-line and off-line reservoirs. A simplified routing scheme and a rainfall-runoff model based on a few essential hydrological parameters were implemented. To validate the proposed design methodology, on-line and off-line routing reservoirs were firstly sized by means of a conventional design storm method for a test watershed located in northern Italy. Their routing efficiencies were then estimated by both analytical-probabilistic models and benchmarking continuous simulations. Bearing in mind practical design purposes, adopted models evidenced a satisfactory consistency
Assessment of the long term efficiency of CSO capture tanks by semiprobabilistic methods
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Proposal of a semi-probabilistic approach for storage facility design
No full textStorage facilities are key devices in mitigating the urban drainage impact on receiving water bodies, but their design is
still affected by high uncertainty. The analytical-probabilistic approach has recently raised interest, because the
facility performances are directly related to probability. Starting from statistically independent storm events,
distributions of the meteorological variables must be fitted. Rainfall series, recorded in three Italian raingauges,
were examined for appraising two main concerns: the choice of proper probability distributions for rainfall volume
and the sample sensitivity with respect to the analysis criterion. The analytical derivation of the model is then finally
discussed
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