Search results for "flood"

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…

Estudio sedimentológico de los depósitos de inundación en la Ribera del Xúqer (Valencia), en octubre de1982

2013

As a result of the sedimentological study of a series of deposits corresponding to the exceptional flood in the Xuquer River in October 1982, we analyze the behaviour of fluvial dynamics. The sedimentary response enables us lo perceive certain differences between the deposits analyzed, bUI these do not completely adjust to the genetic patterns considered in the classic Geomorphology as the producers ofthe traits ofvertical growth generated during floods.

Flash-flooding of Ephemeral Streams in the Context of Climate Change

2021

Ephemeral streams, which are more extended than expected, entail a significant flood risk. Historically they have been underestimated due to their intermittent flow and the lack of knowledge on their hydro-geomorphology. Currently, European legislation recognizes their associated risk and supports research into them, adapting the scale and methodology to their characteristics. Based on the compilation of various works carried out in four Valencian catchments (Eastern Spain), this paper approaches the key questions of rainfall-runoff conversion and flood generation in ephemeral streams, taking into account their hydro-geomorphological specificity. Moreover, the consequences which derive from…

Repercusiones de un fenómeno extraordinario en la Rambla de Chiva

2013

In this paper we have tried fo show that floods only become catastrophic when man acts on them. In order lo confirm such hypotesis causes and consequences of a flood occurred al the Rambla de Chiva ha ve been analysed. The first pan of the article studies the consequences of such phenomenon on the rambla by means of the sedimentology. From this study it can be concluded that floods are a normal phenomenon for river action. The second part is centered in human intervention on the Rambla, which is shown to have had catastrophic effects on it.

Adaptation to Floods in Riga, Latvia: Historical Experience and Change of Approaches

2013

How do the 1982/83 and 1997/98 El Niños rank in a geological record from Peru?

2007

Two very strong El Nino events during the years 1982/83 and 1997/98 caused dramatic economical and social damages worldwide. However, it is quite uncertain how these events rank in a long-term perspective and how frequent events of similar magnitude were in the past. Very-high-resolution proxy data for flood events in the El Nino key region of Peru are presented. Strong flood events in the hyper-arid northern and northern central Peru coastal desert occur during El Nino events. The flood data are derived from a laminated marine sediment core. The proxy data reveal that both modern events were recorded as the strongest sediment discharges in the 106KL flood record over the last millennium. S…

Sorption of polycyclic aromatic hydrocarbons (PAHs) to carbonaceous materials in a river floodplain soil

2007

We report on sorption isotherm of phenanthrene (Phe) for river floodplain soil associated with carbonaceous materials, with particular attention being devoted to the natural loading of Phe. Our sorption experiments with original soil samples, size, and density sub-fractions showed that the light fraction had the highest sorption capacity comparable to low rank coals. In addition, the light fraction contributed most for the sorption of Phe in total soil samples. K(oc) values for all fractions were in the same range, thus indicating that coal and coal-derived particles in all samples are responsible for the enhanced sorption for Phe. Sorption was strongly nonlinear and the combined partitioni…

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…

A major Holocene ENSO anomaly during the Medieval period

2004

[1] Here, we present a high resolution marine El Nino flood record from Peru. A period of extreme drought without strong flooding occurred from A.D. 800–1250. Anomalous precipitation patterns characterized the entire Indo-Pacific ENSO domain, with dry events in the northern Arabian Sea and the mid-latitudes of both Americas, coinciding with wet periods in the Atlantic Cariaco Basin. The occurrence of contemporaneous moisture anomalies in other archives in the ENSO region highlights the role of El Nino strength in global climate evolution during the late Medieval period when temperature reconstructions show a rather heterogeneous pattern.

Constraints on the Cretaceous thermal event in the Transantarctic Mountains from alteration processes in Ferrar flood basalts

1999

Abstract K–Ar and 40 Ar/ 39 Ar incremental-heating analyses on apophyllite formed during hydrothermal alteration of volcanic rocks from the Ferrar Supergroup in North Victoria Land, Antarctica, provide strong evidence for hydrothermal events during mid-Cretaceous time. A last event has been dated at 96.7±0.6 Ma. Variable older ages between 112 and 125 Ma are interpreted as mixed ages of hydrothermal events or may be caused by disturbances of the Ar–Ar system. The Rb–Sr isotope system of the apophyllites is not applicable to dating because a large portion of the Sr is radiogenic and because of Rb-mobility in the crystal structure. Secondary mineralogy suggests a temperature for alteration be…