N. B. Melnikova

Flood early warning system: design, implementation and computational modules

We present a prototype of the flood early warning system (EWS) developed within the UrbanFlood FP7 project. The system monitors sensor networks installed in flood defenses (dikes, dams, embankments, etc.), detects sensor signal abnormalities, calculates dike failure probability, and simulates possible scenarios of dike breaching and flood propagation. All the relevant information and simulation results are fed into an interactive decision support system that helps dike managers and city authorities to make informed decisions in case of emergency and in routine dike quality assessment. In addition to that, a Virtual Dike computational module has been developed for advanced research into dike stability and failure mechanisms, and for training the artificial intelligence module on signal parameters induced by dike instabilities. This paper describes the UrbanFlood EWS generic design and functionality, the computational workflow, the individual modules, their integration via the Common Information Space middleware, and the first results of EWS monitoring and performance benchmarks.

Distributed simulation of city inundation by coupled surface and subsurface porous flow for urban flood decision support system

We present a decision support system for flood early warning and disaster management. It includes the models for data- driven meteorological predictions, for simulation of atmospheric pressure, wind, long sea waves and seiches; a module for optimization of flood barrier gates operation; models for stability assessment of levees and embankments, for simulation of city inundation dynamics and citizens evacuation scenarios. The novelty of this paper is a coupled distributed simulation of surface and subsurface flows that can predict inundation of low-lying inland zones far away from the edge of the flooded area, as observed in St. Petersburg city during the floods. All the models are wrapped as software services in the CLAVIRE platform for urgent computing, which provides workflow management and resource orchestration.

Virtual Dike: multiscale simulation of dike stability

We present a Virtual Dike simulation module developed as a part of a flood Early Warning System (EWS) for the UrbanFlood project. The UrbanFlood EWS is a distributed system that analyzes sensor data received in real-time from flood defenses (dikes, dams, etc.) and simulates dike stability, breaching and flood propagation. The aim of the Virtual Dike module is to develop an advanced multiscale multiphysics simulation laboratory for expert users and numerical model developers. This lab is used to validate simulation models, to plan experiments and to investigate physical processes influencing dike stability and failure. In the first stage of the project, we have studied the structural stability of the Live Dike, a dike protecting a seaport in Groningen, the Netherlands. The four cross-sections of the dike are equipped with sensors of pore pressure and inclination. For each section, 2D simulations of flow through porous media and dike deformations have been performed under tidal water load. Simulation results have been compared with the sensors data in order to calibrate soil properties. Pore pressure, stress dynamics and structural stability of the dike have been analyzed.

Artificial intelligence and finite element modelling for monitoring flood defence structures

We present a hybrid approach to monitoring the stability of flood defence structures equipped with sensors. This approach combines the finite element modelling with the artificial intelligence for real-time signal processing and anomaly detection. This combined method has been developed for the UrbanFlood early warning system and successfully tested on a large-scale sea dike during a simulated strong storm with very high water level. The artificial intelligence module detects the onset of dike instability after being trained on the data from the Virtual Dike finite element simulation.

Modeling earthen dikes using real-time sensor data

The paper describes concept and implementation details of integrating a finite element module for dike stability analysis “Virtual Dike” into an early warning system for flood protection. The module operates in real-time mode and includes fluid and structural submodels for simulation of porous flow through the dike and for dike stability analysis. Realtime measurements obtained from pore pressure sensors are fed into the simulation module, to be compared with simulated pore pressure dynamics. Implementation of the module has been performed for a real-world test case – an earthen levee protecting a sea-port in Groningen, the Netherlands. Sensitivity analysis and calibration of diffusivities have been performed for tidal fluctuations. An algorithm for automatic diffusivities calibration for a heterogeneous dike is proposed and studied. Analytical solutions describing tidal propagation in one-dimensional saturated aquifer are employed in the algorithm to generate initial estimates of diffusivities.

Corrigendum to “Experience of using FEM for real-time flood early warning systems: Monitoring and modelling Boston levee instability”

here ∇ = e-x ∂ ∂x + e-y ∂ ∂y + e-z ∂ ∂z is gradient operator; s is soil density; is gravity vector; -and -eff are total and effective stress tensors, espectively (compressive stresses are negative); = eff − pI in saturated zones, = eff in vadose zones, E is Young’s modulus; is oisson’s ratio; eff = I1 = x eff + y eff + z eff is the first effective stress invariant; I is unit tensor; ε is total strain tensor; q is plastic multiplier; is describes the plastic potential function and the plastic yield function (the associated plastic flow rule has been adopted here).