NH14C-02 An Integrated Modeling Framework for Flood Risk in Coastal Urban Landscapes

Abstract

Major Coastal Urban centers face the risks of storm surge, inland estuarine flooding and urban pluvial flooding. Under climate change they face the added threat of sea-level rise, increases in storm surge, and increased precipitation.

These compound threats of climate change are cast within a world of great uncertainty about the changes in the magnitude and frequency of the separate threats as well as the spatial and temporal correlation. An enhanced risk assessment process is needed to address the risk of the compound events and assessing the cost-benefits of interventions

This research proposes a multi-hazard scalable time sensitive high resolution flood modeling approach to capture the “triple flood threat” (pluvial, fluvial and storm surge flooding) combined implications. The presentation will focus on the modeling and risk assessment of urban landscapes using of 2D hydrodynamic flood model tool as shown in Figure. The urban flooding is modeled using ICM, with detailed geo-specificity of the urban systems driven by scenarios of precipitation and coastal and riverine boundary conditions from the other models in the framework. The other models in the framework are : The Coupled TC Intensity Prediction System (CHIPS), producing wind and precipitation fields over the area of the project. Storm surges are simulated using the ADvanced CIRCulation model (ADCIRC), to compute flow and transport in rivers, estuarine, coastal, and oceanic systems. The inland catchment is modeled using LISFLOOD-FP and will be driven outputs from CHIPS and ADCIRC to produce water surface elevations in the riverine and estuarine reaches of the rivers as boundary conditions for the ICM model.

Integrated Flood Risk Analysis: Urban flooding risk will be estimated using a probabilistic analysis based on monte carlo simulation of tropical storms with the resulting monte carlo ensembles of wind and precipitation fields being cascaded into a final derived distribution of flood depth on the urban landscape.

This work will be presented within a case study of the metropolitan Boston urban region which faces threats from Boston Harbor, the Charles & Mystic Rivers and a highly impervious urban landscape. Interaction with policy makers and stakeholder on the presentation and usefulness of the modeling framework will be reported.
 

Plain-language Summary

This work reports on a framework for assessing compound flood risk to coastal urban landscapes from sea level rise, storm surge, estuarine flooding and rainfall over the urban landscape. A linked modeling system will be presented that provides for a cascading of probabilities so that appropriate level of joint probabilities can be estimated for risk assessments.