Run Your First Model

Your project now has everything a simulation needs: elevation, boundaries, and rainfall. In this step you will gather those inputs into a Scenario, build it, and run it.

Note

A Scenario is the editable model configuration: which inputs to use, at what resolution, for how long. A Run is one compute attempt at a built Scenario. You can change a Scenario and run it again as many times as you like.

Create a Scenario

1. Click Scenarios in the left toolbar to open the Scenarios panel
2. Click New Scenario
3. Enter a name in the Name field (e.g. Existing)

Select your inputs

The Required tab lists the inputs every Scenario needs: Terrain (your elevation/DEM input), Boundary, Inflow, and Rainfall. Hydrata pre-selects the first available layer for each, so with the single set of layers you created in this tutorial there is nothing to change.

The Optional tab (Friction, Structures, Mesh) can be left empty for now: sensible defaults apply. See Selecting Inputs for what each input does and what happens when it is omitted.

Set resolution and duration

Open the Run tab and set the two required parameters:

• Resolution: the target mesh triangle edge length in metres. 10 works well for the tutorial model.
• Duration: how long to simulate, entered as hours and minutes. Try 01:00 for a one hour event.

See Configuring Runs for the full list of settings.

Build, then run

1. Click Build. Hydrata generates the triangular mesh and assembles your inputs into a scenario package. The status moves from Created through Building... to Built.
2. When the status shows Built, click Run.

Watch the status

The status updates automatically as the Run progresses:

Status	What is happening
Created	The Scenario exists but has not been built
Building...	The mesh is being generated and the scenario package assembled
Built	The scenario package is ready to run
Queued	The Run is waiting for cloud compute
Computing	ANUGA is simulating. A progress bar shows percent complete and an estimated time remaining
Processing results...	Result rasters are being generated and published to the map
Complete	Results are ready to view

How long it takes

The tutorial model should build in under a minute and run within a few minutes. Run time scales with mesh size (domain area divided by triangle size) and simulated duration: a detailed catchment model with a million or more triangles typically takes somewhere between 20 minutes and a few hours.

Tip

You don't need to keep the page open. The Run continues on cloud compute, and the status catches up whenever you return to the project.

Warning

If the status shows Error, scroll down to the run log at the bottom of the Run tab to see what went wrong, then click Retry.

Next steps

When the status reaches Complete, your result layers are already on the map. Next: view your results.