Search results for "flooding"

Flood frequency analysis for an urban watershed: comparison between several statistical methodologies simulating synthetic rainfall events

2016

To obtain the flooding frequency distribution for an urban watershed, different methods based on simulations of synthetic rainfall events were compared with an empirical analysis of the flooding data and with the results of long-term simulations. A copula-based multivariate statistical analysis of the main hydrological variables was proposed to generate synthetic hyetographs. Two different approaches were adopted to assess a temporal pattern to the synthetic rainfall: one analyses all available historical rainfall patterns, and another adopts the cluster analysis in three different variants to reduce the computational effort of the analysis. To test the methodology reliability, the analysis…

Geohazard assessment of the north-eastern Sicily continental margin (SW Mediterranean): coastal erosion, sea-level rise and retrogressive canyon head…

2022

Coastal dynamics are the result of several processes controlling the balance between sediment input and output over time. The beach system is not always able to maintain a neutral coastal balance due to natural and anthropogenic causes. We present an integrated marine geology, geomorphological and sea-level rise analysis in the coastal sector between Torre delle Ciavole and Capo Calavà (North-Eastern Sicily, Italy).This sector is characterized by high uplift rates and frequent seismicity (mainly generated by the very active Vulcano-Tindari Fault System), promoting the development of mass-wasting processes in the coastal and offshore sectors. A main erosive feature observed in the area is th…

Pluvial flooding in urban areas: the role of surface drainage efficiency

2018

Pluvial flooding in urban areas may derive from the limited or temporarily reduced efficiency of surface drainage, even when the underlying storm sewers are properly designed. This study focuses on the impact of uncertainties in the operational condition of the surface drainage system on pluvial flood hazard. The flood propagation model FLURB-2D is implemented on a selected study area in the town of Genoa (Italy). Synthetic hyetographs based on the Chicago and bivariate copula methods with suitable return periods are used as input. While simulating the design rainfall, inlet operational conditions are varied stochastically using a Monte Carlo approach. Results confirm that microtopography h…

Short-term emissions of CO 2 and N 2 O in response to periodic flood irrigation with waste water in the Mezquital Valley of Mexico

2015

Irrigation with waste water adds labile carbon and nitrogen compounds to the soil, and when applied by flooding it rapidly changes the soil's atmosphere and redox potential. In the Mezquital Valley more than 90 000 ha is irrigated with waste water from Mexico City, and enhanced emissions of CO2 and N2O follow each flooding. We measured the emissions of these two gases from a field irrigated periodically with waste water and under three crops, namely alfalfa, rye-grass and maize, using static chambers for 21 months. We also measured emissions from a field growing rain-fed maize before and shortly after two rain events. The data from repeated measurements from the same chambers are correlated…

Pluvial flooding in urban areas: the role of surface drainage efficiency

2016

Derivation of Rainfall Thresholds for Flash Flood Warning in a Sicilian Basin Using a Hydrological Model

2016

Abstract The damages caused by flash floods are among the most onerous in terms of loss of lives and damage to properties. Derivation of rainfall threshold is one of the approaches commonly used for the development of flash flood warning systems. Specifically, rainfall threshold is the rainfall amount that, for a given basin area and duration, is enough to cause flooding and, therefore, it indicates the maximal sustainable rainfall for a basin. The aim of this paper is deriving flash flood-rainfall thresholds for a Sicilian basin (Italy) throughout a deterministic approach. The conceptual hydrological model TOPDM was used to estimate the amount of rainfall that, for given duration, hydrolog…

Rainfall thresholds derivation for warning pluvial flooding risk in urbanised areas

2016

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…

Coarse-Grained Barrier Trees of Fitness Landscapes

2016

Recent literature suggests that local optima in fitness landscapes are clustered, which offers an explanation of why perturbation-based metaheuristics often fail to find the global optimum: they become trapped in a sub-optimal cluster. We introduce a method to extract and visualize the global organization of these clusters in form of a barrier tree. Barrier trees have been used to visualize the barriers between local optima basins in fitness landscapes. Our method computes a more coarsely grained tree to reveal the barriers between clusters of local optima. The core element is a new variant of the flooding algorithm, applicable to local optima networks, a compressed representation of fitnes…

Economic transitions in finis terra

2009

A gradualist approach has been taken in describing the evolution of the last foragers in the Iberian Mediterranean Region (IMR) up to their rapid collapse, brought about by the appearance of the first prehistoric farmers. This point of view assumes that the post-Last Glaical Maximum (LGM) climatic change brought about a certain restructuring of the mammal fauna and exerted a direct influence by flooding the changing coastal plain and submerging coastal sites related to marine resource use. This paper proposes that small prey was a constant and structural resource in the IMR that did not signal intensification, since human consumption of rabbits goes back to the Middle Palaeolithic. At the s…

Morphological observations on the co-occurring geophytes Isoetes duriei Bory (Lycophyta, Isoetaceae) and Romulea columnae Sebast. et Mauri (Anthophyt…

2003

Some preliminary observations on the morphoplogy and leaf anatomy of two geophytes, Isoetes duriei and Romulea columnae, co-occurring in a Mediterranean temporary pond, have been reported. The species examined possess characters favourable to the survival of both flooded and arid conditions. The adaptive traits to flooding appear plastic in R. columnae, while I. duriei is “structurally” an aquatic plant. Evolutionary and ecological aspects are briefly discussed.