Search results for "Geomorphology"

Parameter Uncertainty in Shallow Rainfall-triggered Landslide Modeling at Basin Scale: A Probabilistic Approach

2014

Abstract This study proposes a methodology to account for the uncertainty of hydrological and mechanical parameters in coupled distributed hydrological-stability models for shallow landslide assessment. A probabilistic approach was implemented in an existing eco-hydrological and landslide model by randomizing soil cohesion, friction angle and soil retention parameters. The model estimates the probability of failure through an assumed theoretical Factor of Safety (FS) distribution, conditioned on soil moisture content. The time-dependent and spatially distributed FS statistics are approximated by the First Order Second Moment (FOSM) method. The model was applied to the Rio Mameyes Basin, loc…

A coupled eco-hydro-geomorphic investigation of basin response to climate change: Examining the role of climate on internal basin dynamics

2009

Much attention has been devoted to assessing the relationship between changes in climate and landscape evolution. Given the complexity of dependence of geomorphic processes on hydrological and vegetation properties of the system, it is not surprising that different studies of fluvial response to climate change often appear contradictory, making difficult to generalize about how any given drainage basin will respond to changes in climate and/or land use. In this study, an integrated geomorphic component of the physically-based, spatially distributed hydrological model, tRIBS, the TIN-based Real-time Integrated Basin Simulator, is used to analyze the sensitivity of landscapes to climate chang…

Overland Flow Times of Concentration for Hillslopes of Complex Topography

2016

The time of concentration is an important parameter for predicting peak discharge at the basin outlet and for designing urban infrastructure facilities. In studying the hillslope response, employing hydraulic equations of flow, the shape of the hillslope geometry has often been assumed as rectangular and planar. However, natural hillslopes have complex topographies whose shapes are characterized by irregularly spaced contour lines. Recently, kinematic wave time of concentration has been derived for rectangular and curved parallel hillslopes. This paper extends this work to hillslopes of complex planform geometry, considering the degree of divergence or convergence of the hillslope. The exte…

Cross sectional flow in a meandering laboratory channel with vegetated bed

2016

As it is known, the outer-bank of a meander wave is considerably vulnerable to the erosion processes. Literature indicates that cross-stream circulation strongly affects the redistribution of the downstream velocity and boundary shear stress in curved channels. In steep outside bends, beside a central-region circulation cell, a counter-rotating circulation cell often forms in the upper part of the outer-bank region. Accurate understanding of the role of these circulation cells on velocity redistribution in bends is important to define protective measures of the outer-bank. Literature also shows that vegetation could modify flow velocity and turbulent structure. This work reports preliminary…

Procesos fluviales en lechos con materiales gruesos

2013

Fluvíal processes ingravel-bed rívers. The bedload transport processes ingravel-bed rívers are not very known. The two most frequent features that characterize these rívers are the presence of a scour layer and the pavement. The coarse surface layer causes a great resistance to flow in gravel-bed rívers. So, flow resítance equations for computing average velocity can be applíed.

Effect of Vegetation on Fluvial Erosion Processes: Experimental Analysis in a Laboratory Flume

2013

Abstract The plane evolution of a meander wave is determined by the erosion processes at the banks. Particularly, the outer- bank is considerably vulnerable to the erosion processes. Indirect techniques, which act upon the reduction of the effect of the cross-circulation motion, have been recently proposed to limit the outer-bank erosion. This paper shows preliminary results on the role played by vegetation on cross-circulation motion. The analysis is conducted on the basis of experimental data collected in a large amplitude meandering channel constructed at the hydraulic laboratory of DICAM. Maps describing the cross-stream flow, both over the no-vegetated bed and over the vegetated bed, a…

Extraordinary sediment delivery and rapid geomorphic response following the 2008-2009 eruption of Chaitén Volcano, Chile

2016

U.S. Geological Survey Volcano Science Center SERNAGEOMIN's Programa de Riesgos Volcanicos Conicyt Fondecyt grants 1110609 1141064 11130671 Conicyt Fondap 15090013 Vamos Research Centre

STOP 1: Lower Gauja spillway valley at Sigulda

2014

STOP 9: Upper Daugava spillway valley and associated gully network at Vasargelišķi

2014

tRIBS-Erosion: A parsimonious physically-based model for studying catchment hydro-geomorphic response

2012

Our goal is to develop a model capable to discern the response of a watershed to different erosion mechanisms. We propose a framework that integrates a geomorphic component into the physically-based and spatially distributed TIN-based Real-time Integrated Basin Simulator (tRIBS) model. The coupled model simulates main erosive processes of hillslopes (raindrop impact detachment, overland flow entrainment, and diffusive processes) and channel (erosion and deposition due to the action of water flow). In addition to the spatially distributed, dynamic hydrologic variables, the model computes the sediment transport discharge and changes in elevation, which feedback to hydrological dynamics throug…