Cet article analyse les relations conceptuelles (imprecises) de la vulnerabilite, de la resilience et de la capacite d’adaptation aux changements climatiques selon le systeme socio-ecologique (socio-ecologigal systems – SES) afin de comprendre et anticiper le comportement des composantes sociales et ecologiques du systeme. Une serie de questions est proposee par l’auteur sur la specification de ces termes afin de developper une structure conceptuelle qui inclut les dimensions naturelles et so...

Linkages between vulnerability, resilience, and adaptive capacity

Computer Aided Civil and Infrastructure Engineering

In many parts of the world, groundwater resources are under increasing threat from growing demands, wasteful use, and contamination. To face the challenge, good planning and management practices are needed. A key to the management of groundwater is the ability to model the movement of fluids and contaminants. The purpose of this book is to construct conceptual and mathematical models that can provide the information required for making decisions associated with the management of groundwater resources, and the remediation of contaminated aquifers. The basic approach of this book is to accurately describe the underlying physics of groundwater flow and solute transport in heterogeneous porous media, starting at the microscopic level, and to rigorously derive their mathematical representations at the macroscopic levels.

Modeling groundwater flow and contaminant transport

The stepped spillway has increasingly become and effective energy dissipator. When the hydraulic performance of the overflow is clearly known, the energy dissipation could be increased. However, the study of stepped spillway overflow has been based only on model tests until now. In this paper, the \ik-ϵ turbulence model is used to simulate the complex turbulence overflow. The unstructured grid is used to fit the irregular boundaries and the volume of fluid method is introduced to solve the complex free-surface problem. The free surface, velocities, and pressures on the stepped spillway are obtained by the turbulence numerical simulation. Furthermore, the simulation results compare well with measured data. The study indicates that the turbulence numerical simulation is an efficient and useful method for the complex stepped spillway overflow.

Volume of Fluid Model for Turbulence Numerical Simulation of Stepped Spillway Overflow

Stepped chutes have become recently a popular method for discharging flood waters. The steps increase significantly the rate of energy dissipation taking place on the spillway face and reduce the size of the required downstream energy dissipation basin. This paper reviews the hydraulic characteristics of skimming flows. The onset of skimming flows is discussed. New results are presented to estimate the flow resistance along stepped chutes. The study indicates some major difference between the flow patterns on steep and flat stepped chutes. An analogy with flow over large roughness is developed. Then the calculations of the start of air entrainment are detailed. The results indicate that free surface aeration occurs much more upstream than on smooth spillways. The effects of flow aeration are later discussed.

https://espace.library.uq.edu.au/view/UQ:9384/jhr94_3.pdf

Hydraulics of skimming flows over stepped channels and spillways

Gabions are a common construction material in the African Sahel and elsewhere, especially for spillways. Stepped gabion spillways are structurally stable, resistant to water loads, and efficient energy dissipators, but there are no clear design rules to date. One‐fifth‐scale model tests representing 3–5 m high standard prototypes discharging up to 3m3⋅s-1⋅m-1 enabled us to establish quantified energy‐dissipation criteria and efficient stilling‐basin design rules, saving 10–30% on basin length as compared with current methods. The different types of flow over the stepped face are also described and analyzed: isolated nappe flow, partial nappe flow, and skimming flow. From a technical point of view, stepped gabion spillways can withstand flows up to 3m3⋅s-1⋅m-1 without great damage, if setting of gabions complies faithfully with the code of practice. Some advice is given on preventing gabion deformation.

Flow and Energy Dissipation Over Stepped Gabion Weirs

Reliability analysis of embankment dam sliding stability using the sparse polynomial chaos expansion

Probabilistic stability analysis of an earth dam by Stochastic Finite Element Method based on field data

Diagnosis and risk analysis are essential to ensure the safety of dams. Dam specialist engineers have useful methods available to help them in their task: physical modelling for assessing dam stabi...

Dam ageing diagnosis and risk analysis: Development of methods to support expert judgment

(1991) Flows and dissipation of energy on gabion weirs La Houille Blanche: Vol 77, No 1, pp 37-47

/pdf/ecoulement-et-dissipation-sur-les-deversoirs-en-gradins-de-5434tjpucc.pdf

Laurent Peyras

Papers

Flow and Energy Dissipation Over Stepped Gabion Weirs

Reliability analysis of embankment dam sliding stability using the sparse polynomial chaos expansion

Probabilistic stability analysis of an earth dam by Stochastic Finite Element Method based on field data

Dam ageing diagnosis and risk analysis: Development of methods to support expert judgment

Ecoulement et dissipation sur les déversoirs en gradins de gabions