Search results for "flood"

Drastic innovation reduces firms’ incentives to create divisions

2020

I study a game in which two firms create independent divisions, then they choose whether to do R&D so as to reduce their divisions’ marginal costs, and then the divisions compete in the market. I provide necessary and sufficient conditions under which the game has an equilibrium in pure strategies, and I show that the game has an equilibrium only if each firm threatens that if the rival creates more divisions it will use R&D to foreclose the market. The case we find in the literature, in which firms flood the market with their divisions, should happen only in industries with low returns to R&D.

Probabilistic Flood Hazard Mapping Using Bivariate Analysis Based on Copulas

2017

This study presents a methodology to extract probabilistic flood hazard maps in an area subject to flood risk, taking into account uncertainties in the definition of design hydrographs. Particularly, the authors present a new method to produce probabilistic inundation and flood hazard maps in which the hydrological input (i.e., synthetic flood design event) to a 2D hydraulic model has been obtained by using a bivariate statistical analysis (copulas) to generate flood peak discharges and volumes. This study also aims to quantify the contribution of boundary conditions’ uncertainty in order to evaluate the effect of this uncertainty source on probabilistic flood hazard mapping. Different comb…

Effects of initialization on response of a fully-distributed hydrologic model

2008

Summary Knowledge of initial conditions is very important to correctly model the basin response at the storm event scale. Of particular interest is the influence of topography and soil type on the principal hydrologic variables and runoff generation mechanisms as a function of antecedent wetness conditions. This study addresses the influence of initial states on the short-term hydrologic response and characterizes the effects of topography and soils on the dissipation of the influence of the initialization conditions. Two case studies are considered: a synthetic two-dimensional planar hillslope with various assumed slope magnitudes and soil types; and a real basin (∼800 km2) with actual lan…

Flash floods in Mediterranean ephemeral streams in Valencia Region (Spain)

2016

Summary Ephemeral streams are typical Mediterranean fluvial systems with high risk of flash flooding, and few data are available about these systems in most locales. However, the SAIH network (Automatic Hydrological Information Systems) of the Jucar River Water Authority has been providing detailed information about ephemeral streams in Spain every 5 min since 1988. Using these data, we evaluated the processes of rainfall–runoff conversion and flood generation in five Mediterranean ephemeral streams ranging in size from 25 to 450 km 2 . To provide a general framework for hydrological analysis, the study included 142 flash flood events registered between 1989 and 2007. A more detailed analys…

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…

Drainage inlets efficiency and its impact on pluvial flooding hazard evaluation uncertainty

2014

Flooding events in urban areas occur quite frequently as a consequence of rain events of lower intensity than the design one, even in case of correct network dimensioning. Inlets are in those cases the critical nodes, and efficient drainage is only ensured when care is taken on their appropriate design and positioning within the pluvial flood-prone areas. Classical approach for design and position of these hydraulic structures can result in high level of uncertainty in defining properly risk levels in urban areas. Further, evaluation of flood hazard in urban areas is made even more difficult if one considers that pluvial flooding can be caused by storm events characterised by a low return t…

NOVEL APPROACHES FOR FLOOD RISK ASSESSMENT USING EXPOSURE-VULNERABILITY MATRICES

L’approccio “classico” di difesa dall’inondazione, basato sulla costruzione di opere strutturali in grado di contenere piene di tempo di ritorno sempre maggiore, è stato sostituito da un approccio gestionale del rischio da inondazione, nel quale prende piede sempre più il concetto di “convivere” con la piena accettando un certo livello di inondazione. In quest’ottica, la vulnerabilità diventa la variabile chiave nell’equazione del rischio e gli interventi non strutturali lo strumento principale per mitigarlo: nonostante si creda nella loro efficacia, i metodi per stimarla sono pochi, così come scarsi sono i dati sui loro effetti. Il 22 Novembre 20112, un evento meteorico eccezionale ha colp…

Runoff Generation in Badlands

2019

Capítulo 5.

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…

Flood pattern changes in the rivers of the Baltic countries

2015

Estimation of both the frequency and variation of spring floods is a key issue for the assessment and management of flood risks. Changes in river floods in Estonia, Latvia and Lithuania have been investigated in few national studies. However, there are no studies of the changes of flood patterns by using a common methodology for the rivers of this region. In this study flood pattern changes in the rivers of the Baltic countries were estimated applying trend and frequency analysis for the periods of 1922–2010, 1922–1960, 1961–2010 and 1991–2010, i.e. for the whole spring flood data sets, periods before and after 1960 (this year was considered as the beginning of the remarkable climate change…