---
title: "How to start a new 1D river simulation | Tutorials"
slug: "how-to-start-a-new-1d-river-simulation"
description: "Learn how to start a new 1D river simulation in Flood Modeller. "
tags: ["1D river modelling", "running simulations"]
updated: 2022-08-03T05:56:39Z
published: 2022-08-03T05:56:39Z
canonical: "help.floodmodeller.com/how-to-start-a-new-1d-river-simulation"
stale: true
---

> ## Documentation Index
> Fetch the complete documentation index at: https://help.floodmodeller.com/llms.txt
> Use this file to discover all available pages before exploring further.

# How to start a new 1D river simulation

A simulation is defined in a simulation file. For 1D river simulations  this is a text file that has a file extension “.ief”. 

The **Simulations** tab provides functionality to start new simulations and load  existing simulations. You can also  run simulations from here.

To start a new simulation, your [River Network](/v1/docs/1d-river-networks) should already be  defined. It is easiest if this is also  loaded into Flood Modeller, however this is not necessary (and so for larger networks, it is possible to save time by not loading the network itself).

In the **Project** panel, click on the section header **Simulations** to highlight it. In the **Simulations** tab,  click **New 1D Simulation**.  You will be prompted to provide a filename and save location for the new simulation file in a standard browser window.

![1DRiverimagesnewsimulation.PNG](https://cdn.document360.io/5074bc26-a9ef-4bf4-b1de-a5c6ce628aca/Images/Documentation/1DRiverimagesnewsimulation.PNG)

Note: You can also start a new 1D simulation by right-clicking on the **Simulations** section of the **Project** panel  and selecting **New 1D Simulation** from the displayed menu.

Your simulation name will be added to the **Simulations** section of the **Project** panel. You can right-click the simulation name for further options, including **Open** to view the simulation details.

![1DRiverimagesnewsimulation2.PNG](https://cdn.document360.io/5074bc26-a9ef-4bf4-b1de-a5c6ce628aca/Images/Documentation/1DRiverimagesnewsimulation2.PNG)

## Related topics
More about  [1D River Simulations](/v1/docs/1d-river-simulations)