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---
title: Document Info
reportDate: March 2026
reportType: Computer Program Document
reportTitle: LifeSim
reportSubTitle: Applications Guide
reportAuthors: ['Susie Byrd, Risk Management Center']
reportAbstract:
reportAcknowledgments: xx
reportSubjectTerms:
responsiblePersonName: xx
responsiblePersonNumber: ###-###-####
---

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# Document Information

<DocumentMetadata metadata={frontMatter} />
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---
title: Version History
---

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# Version History

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dates={['March 2026']}
descriptions={["Initial release of LifeSim Applications Guide"]}
modifiedBy={['Susie Byrd']}
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approvedBy={['xx']}
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---
title: "Preface"
---

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# Preface

LifeSim is the life loss and direct damage estimation software used by the U.S. Army Corps of Engineers. LifeSim is designed to simulate the entire
warning and evacuation process for estimating potential life loss and direct economic damages resulting from floods. The following is a description of
the major capabilities of LifeSim:

Graphical User Interface

Agent Based Modeling

Evacuation Simulation

Uncertainty

Graphics and Reporting

The user interacts with LifeSim through a graphical user interface (GUI). The interface is designed to make it easy to use the software, while still
maintaining a high level of efficiency for the user.

LifeSim uses an agent-based approach to track individuals throughout the warning and evacuation process. During an evacuation, agents are interacting
with the roads, other vehicles, and the incoming hazard. After the warning and evacuation process has been simulated, LifeSim calculates lethality for
those people who are exposed to the hazard and the associated direct damages. By tracking individual people and their movements, LifeSim can help
identify where people are most at risk of losing their lives, whether it is on roads or in structures.

Three modes of evacuation are included in LifeSim: cars, sports utility vehicles (SUVs), and pedestrians. For vehicular evacuation, a dual regime
modified Greenshields model (USDOT) in conjunction with spillback enforcement is used for traffic propagation to represent the effects of traffic
density and road capacity on vehicle speed. Each road is assigned default values for the number of lanes, free flow speed, traffic jam densities, and
minimum stop-and-go speeds based on the Highway Capacity Manual (HCM) (TRB 2000).

To define the routes people use to evacuate, a road network is provided where each segment of the network contains information such as road category,
directionality, ground offset (for bridges), and interconnectivity. The road network can be imported from an existing GIS polyline shapefile or from
OpenStreetMap. OpenStreetMap is a collaborative project to create a free editable map of the world. During each timestep at the user defined interval
Δt, evacuating groups (PAR evacuating from a structure in a single vehicle) move as far as the model allows until the group reaches a destination
point, gets caught, or becomes stranded. More information on the evacuation simulation can be found in the (RMC 2021).

LifeSim applies both natural variability and knowledge uncertainty through Monte Carlo analysis. Multiple parameters can be entered with uncertainty
including those that influence the warning and evacuation timeline. Each iteration in a simulation represents a scenario that could occur given the
data uncertainties in the model. The results of the analysis provide a distribution of estimated consequences from a given hazard.

<CitationFootnote />
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---
title: "Introduction"
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# Introduction

Welcome to the U.S. Army Corps of Engineers LifeSim Applications Guide. LifeSim uses an agent-based methodology for estimating life loss with the
fundamental intent to simulate population redistribution during an evacuation. Direct life loss, direct economic damages, and direct agriculture
damages are then determined by the hazard (e.g., flooding). Direct consequences, the primary focus of LifeSim, are those incurred when people,
structures, or agricultural resources interact with the hazard.

LifeSim is designed to simulate the entire warning and evacuation process for estimating potential life loss and direct economic damages resulting from
catastrophic floods (e.g., riverine flooding, coastal flooding, dam breach, and levee breach). LifeSim applies both natural variability and knowledge
uncertainty (i.e., naturally occurring change in models’ parameters and outputs and gaps in what can be known by the modelers at the time) through
Monte Carlo simulation. Many parameters can be entered with uncertainty including those that influence the warning and evacuation timeline (see the ,
Warning and Evacuation Timeline Section for a more detailed overview). LifeSim is a multifaceted consequence estimation tool that can be utilized for various
types of studies and analyses, including dam safety, levee safety, coastal storm risk management, flood risk management, risk communication, and
more.

## Overview of this Guide

The LifeSim Applications Guide contains written descriptions of seven examples that demonstrate the main features of the LifeSim software. The
discussions in this manual contain detailed descriptions for the data inputs and analysis of the output for each example. The examples show and
describe various input and output screens used to enter the data and view the output. The examples are intended as a guide for performing similar
analyses in LifeSim. The manual is organized as follows:

<strong>Summary of LifeSim Inputs</strong>, details the required inputs for all LifeSim studies. This section also defines and explains the inputs.
Finally, some recommended data pre-processing is discussed. Reference back to this section for additional information on Hydraulic Data, emergency
planning zones, Structure Inventories, Alternatives, and Simulations.

<strong>Example 1, Estimating Consequence for Levees and Floodwalls</strong>,<strong> </strong>demonstrates the data required to estimate consequences
(life loss and direct economic damages) for a levee or floodwall breach. The example details required inputs, ways to acquire emergency preparedness
information for populations at risk (PAR) and emergency management agencies (EMAs), how to simulate evacuation, and how to analyze your modeling
results.

<strong>Example 2, Estimating Consequences for Dams</strong>, demonstrates the data required to estimate consequences for a dam breach model. The
example details potential Geospatial Information System (GIS) pre-processing needed for data inputs, editing your structure inventory for accuracy,
and inputting warning and evacuation data specific to dams.

<strong>Example 3, Estimating Consequences for Cascading Dam Breaches</strong>, demonstrates various ways to model cascading dam breaches. The example
highlights the modeling differences if there is a downstream dam that breaches due to an upstream dam breaching. This example primarily focuses on
differences in (1) selecting the hazard occurrence time (i.e., the date and time breach or overtopping occurs in the study area) and (2) the
delineation and parameter selection of the emergency planning zones (i.e., zones in LifeSim that can uniquely sample uncertainty parameters).

<strong>Example 4, Estimating Consequences for Coastal Infrastructure</strong>,<strong> </strong>illustrates how LifeSim modeling differs for coastal
structures (e.g., floodwalls, seawalls, dunes, and levees) compared to riverine infrastructure (e.g., floodwalls and levees), including differences in
hydraulic data, warning times, and other consequence nuances specific to coastal infrastructure.

<strong>Example 5, Estimating Life Loss in Flood Risk Management Planning</strong>, details how to compare life loss across an array of Planning
alternatives in LifeSim. This example shows how to use typical Planning hydraulic outputs (e.g., eight flow-frequency events typically used in
Hydrologic Engineering Center’s Flood Damage Reduction Analysis [ HEC-FDA]) in LifeSim to estimate expected annual life loss and how to utilize these
results in the Planning process.

<strong>Example 6, Estimating Direct Economic Damages for Flood Risk Management Planning</strong>, focuses solely on generating accurate direct
economic damages with more uncertainty than the default parameters. The chapter details how to edit and create structure occupancy types, adjust
stage-damage curve uncertainty, adjust foundation height uncertainty, and adjust structure value uncertainty.

<strong>Example 7, Estimating Consequences Using Summary Grids</strong>,<strong> </strong>demonstrates how to estimate life loss and economic damages
using summary grid output which differs from using Hierarchical Data Format (HDF) files from Hydrologic Engineering Center’s River Analysis System
(HEC-RAS). This example will be helpful for individuals attempting to estimate consequences for a smaller Planning study, a study that did not utilize
unsteady flow in HEC-RAS, or a study with limited output or information from the hydraulic model.

<CitationFootnote />
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