Last Modified: 2023-06-23 10:32:50.052

Software Version

HEC-WAT Version 1.1.0 was used to create this example. You can open the example WAT study with HEC-WAT Version 1.1.0 or a newer version.  RAS version 6.1.0 is expected to be installed.

Download Project Files: Setting_Up_FRA_Simulation.7z

Introduction

This model has been trimmed to be more efficient. HEC-RAS has been removed from the program order, and the Hydrologic Sampler (HS) has been added along with an HS alternative.

Purpose

This workshop will guide you through creating a HEC-WAT model with a Flood Risk Analysis (FRA) compute. This workshop will build on the training and understanding of the previous workshops and show the steps necessary to set up the necessary WAT components for computing an FRA simulation.

The files in the watershed folder include a Hydrologic Sampler alternative. We decided to work through the mechanics of the WAT settings before introducing the Hydrologic Sampler to help with the language associated with the FRA compute such as Realizations, Lifecycles, and Events.

  • For the intents of this workshop the Event is a period of continuous simulation that is less than 1 year of duration.
  • Realizations represent a large number of computes all using the same parameters for the knowledge uncertainty parameters. The output of a Realization should represent our best expectation for a given output variable in light of random natural variability.
  • Lifecycles represent a series of events that are collected together, typically lifecycles are 30, 50, or 100 years depending on the project type under consideration. The duration of a lifecycle is defined by the Analysis Period in HEC-WAT.