In HEC-WAT, a simulation is created by combining an analysis period and an alternative to compute results across the models in the program order for a given time window. 

Note

At least one analysis period must exist before a simulation can be created within an alternative. 

Types of Simulations

HEC-WAT provides users with the ability to create two kinds of simulations:  Deterministic and Flood Risk Analysis.

The two different compute types provide flexibility for various use cases. Deterministic computes are used to evaluate a historical event, perform model calibration, or evaluate a hypothetical event. During a deterministic compute, HEC-WAT does not facilitate any uncertainty in the compute, and the results are therefore deterministic in nature. An exception to this definition may occur if a plugin implements its own uncertainty for a deterministic event. The Flood Risk Analysis (FRA) compute is a stochastic compute where HEC-WAT facilitates a nested loop Monte Carlo analysis which separates natural variability and knowledge uncertainty. The FRA compute provides the user the ability to evaluate various project performance metrics consistent with ER 1105-2-100 and ER 1105-2-101. Many users find creative uses of the two computes to achieve the goals of their project.

Both simulation types can be created and managed from the Study tab or from the Alternative and Simulation Manager.

Simulation Requirements and Management - General 

Depending on the type of simulation (deterministic or FRA), different program setup, tools, management and computing options exist. Therefore, information that applies to both types of simulations is described in the following sections:

  • Managing Simulations – provides instructions for using the individual simulation shortcut menu commands (i.e., view, edit, compute, delete, etc.).
  • Alternative and Simulation Manager – highlights the convenient capabilities of the Alternative and Simulation Manager for creating, deleting and accessing the individual simulation shortcut menu commands.
  • Program Order – describes how to create, edit, manage and delete a program order.
  • Time Window Adjustments – provides instructions for adjusting the simulation time window for specific model alternatives in the simulation.

Simulation Requirements and Management - Specific to Simulation Type

Information specific to each simulation type is described separately in the following sections:

Deterministic Simulation

The Deterministic Simulation section includes information on creating, editing, computing and viewing results for deterministic simulations;. The following sections contain deterministic specific information:

Flood Risk Analysis Simulation

The Flood Risk Analysis (FRA) Simulation section includes information on creating, editing, computing and viewing results for FRA simulations; in addition, this section describes FRA-specific tools and computing capabilities. The following sections contain FRA specific information: