GUI

Hydra’s desktop application lets you load, run, and explore water network simulations without using the command line.

Download and Install

Download the installer for your platform from the releases page.

macOS — “Hydra is damaged and can’t be opened”

macOS Gatekeeper blocks apps that are not code-signed. After dragging Hydra to Applications, run this once in Terminal:

xattr -cr /Applications/Hydra.app

Then open the app normally.

Basic Workflow

Hydra organises work into projects. Each project holds a network model and one or more scenarios — independent parameter sets you can run and compare.

1. Create a project — on the Projects screen, click New Project. Choose Import INP file to bring in an existing EPANET .inp file, or start from a blank network.
2. Configure and run — press ⌘R (macOS) or Ctrl+R (Windows/Linux), or click the Simulate button in the scenario strip at the bottom of the screen. Select which scenarios to run and confirm.
3. Explore results — after the simulation completes, the network map updates with colour-coded results. Click any node or link to inspect its time-series values (pressure, head, flow, velocity, water age, etc.). Use the timeline scrubber to step through reporting periods.

Accessing Output Files

Hydra saves output files inside the project folder on disk. To open the folder for a scenario, go to the Scenarios panel and click the Open in Finder (macOS) / Open in Explorer (Windows) icon next to the scenario name. The folder contains:

• results.out — EPANET-compatible binary output, readable by post-processing tools
• results.rpt — plain-text report in EPANET report style

Supported Networks

Any EPANET 2.3 .inp file works directly — no conversion needed. See INP Format Support for the full coverage list.

Troubleshooting

See the Troubleshooting page for common issues including the macOS Gatekeeper error and Windows Defender prompts.