Introduction¶

The HEC-RAS adapter allows use of HEC-RAS model setups in MIKE WORKBENCH. The adapter supports unsteady 1D-flow models.

Limitations¶

Only HEC-RAS 5.0.3 is supported.
The user is required to provide the projection. Without it, model objects can only be created without GIS information.
Model objects are only enabled if the model setup can be parsed by the adaptor. If the setup contains details not supported, some or all model objects will be ignored. The input and output time series will still be configured, but without the geographical information (schema layout) and model variables as described by model objects.
Because MIKE OPERATIONS only supports the updating of input timeseries (as opposed to constant value), steady flow models can be imported by the boundary conditions might not be able to edited.
Initial conditions should be defined both as output and input in HEC-RAS for MIKE OPERATIONS to be able to reuse them from one simulation to another.
Because HEC-RAS does not support Data Assimilation module, no automatic correction of water level or discharge is enable with the adaptor.
2D models can be imported but 2D outputs cannot be visualized within MIKE OPERATIONS.

Model objects¶

The below list of model objects can be derived from a HEC-RAS setup.

Reach
- Location (GIS layer)
- Name
Cross section
- Location (GIS layer)
- River
- Chainage
- Output timeseries (H/Q)
Bridge/culvert
- Name
Inline structure
- River
- Chainage
- Name
- Weirs list
- Gates list
Lateral structures
- Name
- Culvert list
- Timeseries
Junction
- Name
Storage area
- Location (GIS layer)
- Name
- Timeseries
Storage area connection
- Location (GIS layer)
Boundary
- Location (GIS layer)
- Name
- Timeseries
2D flow area
- Location (GIS layer)

Configuration¶

How to set up Initial conditions in HEC-RAS¶

If you want to include your HEC-RAS model in a real time system, it is important to configure the hydraulic model so that it generates and uses hot starts. This is a key aspect of ensure consistency from one simulation to another, increasing the quality of the output.

HEC-RAS can create an “rst” hotstart files in the folder where the project file is stored (prj). The following steps will explain how to set up your model to create and use such a file.

Once the model is updated, it is important to run your model once before registering it in MIKE Workbench. |Description|Illustration| |-|-| | Open the HEC-RAS model | ./HECRAS/image1.png | | Open the Unsteady Flow analysis options | ./HECRAS/image2.png | | Click Options

Select “Output Options…” | ./HECRAS/image3.png | | Select either:
Write Initial Conditions file(s) during simulation
or
Write Initial Conditions file at the end of the simulation

This will ensure the hotstart file is generated by each simulation | ./HECRAS/image4.png | | Now we should be indicate the engine that it should use rst file as initial condition.

This is done in the main editor.

Click Edit.

Select Unsteady Flow Data… | ./HECRAS/image5.png | | Point to an rst file in the folder where the project file is located.

The adaptor will make sure this path is updated before each run. | ./HECRAS/image6.png |

How to run HEC-RAS in Jobs and as background process¶

HEC-RAS requires users to accept the terms and conditions before being able to use the software. This is done when HEC-RAS is opened for the first time by a given user on a given computer.

$C:\DHI\Untitled.png$

When running a model from MIKE Workbench as Foreground process (i.e. the user interface directly runs the model and freezes), the account of the user that opened the MIKE Workbench is used to open HEC-RAS. If this user has already opened HEC-RAS and accepted the HEC-RAS term and conditions, the model will run.

In the case the scenario is run as background, it is sent to the Job Manager Service. This Service is usually logged in with another account.

This account typically did not accept the HEC-RAS terms and conditions. It will not be able to run an HEC-RAS model. In order to fix this, it is either possible to change the “Log on As” to another user account (that has accepted the conditions) or it is possible for the Job Service user (e.g. Local System) to accept the HEC-RAS terms and conditions, as explained below.

Description	Illustration
Download “Sysinternals PsTools” from http://technet.microsoft.com/en-us/sysinternals/bb896649
Unzip
Start a command prompt as administrator
Run the following command from the folder where PsTools was unzipped to “psexec -hsi cmd”
Agree to License Agreement
An new command prompt opens (as localsystem)
Write the following command cd C:\Program Files (x86)\HEC\HEC-RAS\5.0.3 And then ras.exe
If you receive the following error message Go to Regions and copy current settings to system account (assuming the current user can open HEC-RAS) Run again ras.exe in command prompt
Accept Terms and conditons