---
title: "Setting up a 1D river simulation - how to configure the Hydrology tab"
slug: "how-to-configure-the-hydrology-tab"
description: "Learn how to configure the Hydrology tab when setting up a 1D river simulation."
tags: ["1D river modelling", "running simulations", "hydrology", "rainfall-runoff", "ReFH", "FSR"]
updated: 2022-08-03T06:03:41Z
published: 2022-08-03T06:03:41Z
canonical: "help.floodmodeller.com/how-to-configure-the-hydrology-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 Hydrology  tab

Note: to 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 **Hydrology** tab of the **1D Simulation** window, adjustments to your river hydrology can be optionally specified.

Options defined on this tab will override options specified within relevant upstream boundaries in your river network  at simulation runtime. The underlying boundary nodes within your network will be unaffected - the override only applies for this simulation. The options will apply to all boundaries that  [Allow Hydrology overrides](/v1/docs/how-to-allow-hydrology-parameter-overrides-to-a-river-network-at-simulation-runtime).


The Hydrology tab is not shown by default. In the 1D simulation window, click **View** > **Tabs** > **Hydrology** to access this tab.  

![1DRiverimages1dsimhydrologytab.PNG](https://cdn.document360.io/5074bc26-a9ef-4bf4-b1de-a5c6ce628aca/Images/Documentation/1DRiverimages1dsimhydrologytab.PNG)

In the upper part of the Hydrology tab, you can choose an alternative storm duration and/or flood return period. These values will override those provided within all  **FSSR**, **FEH**, **ReFH** and **ReFH2** boundaries present within the river network. As mentioned above, the underlying data provided within the boundary node property forms  will be unaffected - the override only applies for this simulation. By default, all  FSSR, FEH, ReFH and ReFH2  boundaries will  [Allow Hydrology overrides](/v1/docs/how-to-allow-hydrology-parameter-overrides-to-a-river-network-at-simulation-runtime).

To apply a new parameter, tick the appropriate box and enter the required value to be used by the simulation.

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

In the lower part of the Hydrology tab, you can choose scaling factors to apply to the rainfall and/or total flow specified in your inflow nodes. This scaling  can be selected to apply to **Rainfall/Runoff**	  boundaries (**FSSR**, **FEH**, **ReFH**,  **ReFH2** and  **Generic  Rainfall-Runoff**	  boundaries) and to  **Flow-Time** boundaries, or  **Rainfall-Evaporation**	  boundaries, as relevant.  By default, all of these  boundaries will  [Allow Hydrology overrides](/v1/docs/how-to-allow-hydrology-parameter-overrides-to-a-river-network-at-simulation-runtime).

To apply a scaling factor, tick the boxes to specify which node types to apply factors to and enter the required value in the associated box, as shown below.

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

Don't forget to **Save** any changes made to your simulation!

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