---
title: "Setting up a 1D river simulation - how to configure the Times tab"
slug: "how-to-configure-the-times-tab"
description: "Learn how to set up a 1D river simulation and how to configure the Times tab. "
tags: ["1D river modelling", "running simulations", "boundary conditions"]
updated: 2022-11-06T12:29:50Z
published: 2022-11-06T12:29:50Z
canonical: "help.floodmodeller.com/how-to-configure-the-times-tab"
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.

# Setting up a 1D river simulation - how to configure the Times tab

NoteTo follow this guide, a 1D river simulation must be loaded and active. You must therefore initially [Start a new 1D river simulation](/v1/docs/how-to-start-a-new-1d-river-simulation) or [Load a 1D river simulation](/v1/docs/how-to-load-a-1d-river-simulation).

In the **Times** tab of the **1D Simulation** window, the simulation type and timing details must be provided.

![1DRiverimages1dsimtimestab.PNG](https://cdn.document360.io/5074bc26-a9ef-4bf4-b1de-a5c6ce628aca/Images/Documentation/1DRiverimages1dsimtimestab.PNG)

The **Simulation Type** must be selected. By default, new simulations will be set to **Steady (Direct)** - this is particularly useful for creating [Initial Conditions](/v1/docs/initial-conditions-overview)

We also recall these initial conditions could be used in, for example, an **Unsteady (Fixed Timestep)** simulation.

Select the simulation type required using the radio buttons provided. Further details on the options available here can be found in the Technical Reference section.

The **Timing Details** for the simulation also must be provided. In each case, click in the relevant field and type the value required. Don't forget to save any changes made. Fields available for the timing details are dependent on the simulation type selected, click a simulation type for further details.

#### Steady (Direct)

The **Start Time** must be provided, as an absolute value (time/date) or a relative time in hours. An absolute value (time/date) for **Time Zero** can be optionally specified. All other fields are disabled.

---

#### Steady (Timestepping)

The **Start Time** must be provided, as an absolute value (time/date) or a relative time in hours. The **Timestep** also must be provided, in seconds. An absolute value (time/date) for **Time Zero** can be optionally specified. All other fields are disabled.

---

#### Unsteady (Fixed Timestep)

The **Start Time** and **Finish Time** must be provided, as an absolute value (time/date) or a relative time in hours. The **Timestep** also must be provided, in seconds. The **Save Interval** can be adjusted - this is the frequency at which results are saved. An absolute value (time/date) for **Time Zero** can also be optionally specified.

---

#### Unsteady (Adaptive Timestep)

This simulation type provides identical options to Unsteady (Fixed Timestep) described above, with the addition of two fields specifying a Minimum Timestep and Maximum Timestep, in seconds.

---

#### Boundary Mode

The **Start Time** and **Finish Time** must be provided, as an absolute value (time/date) or a relative time in hours. The **Timestep** also must be provided, in seconds. An absolute value (time/date) for **Time Zero** can also be optionally specified.

---

For more advanced users, a **Warm Up Time** can also be provided if you have selected to **Perform Warm Up Start** (on the **Options** tab).

The .mmm file will be created when your simulation runs, and will contain the maxima, minima and mean values of all the main output variables. By default, these values are calculated from time zero to the the simulation finish time, however different **Timing for mmm calculations** can be specified. Further details can be found in the [Specify mmm Times](/v1/docs/the-max-min-mean-file) section.

The **Toolbar** provides functionality to **Save** the details provided so far to the simulation file, and to **Close** the simulation window. You can also **Run**your simulation from here - recall you will want to also [Configure the Files tab](/v1/docs/how-to-configure-the-files-tab) prior to running a simulation.