---
title: "Preparing a Water Quality Datafile | Water Quality"
slug: "preparing-a-water-quality-datafile"
description: "Learn how to prepare a water quality datafile and which datafiles are needed. "
tags: ["1D river modelling", "running simulations"]
updated: 2022-08-04T12:20:25Z
published: 2022-08-04T12:20:25Z
canonical: "help.floodmodeller.com/preparing-a-water-quality-datafile"
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.

# Preparing a Water Quality Datafile

Two datafiles are required as input for the 1D Water Quality simulation:

- **File with file extension '.dat':** This file is needed for the 1D hydraulic simulation and contains all the information needed to describe the channel to be modelled, together with data relating to the boundary conditions.
- **File with file extension '.con':** This file contains details of pollutants to be modelled.

You may either get these files and you may want to edit the data, or enter the data into a new file yourself. For the first one you can use the Flood Modeller Interface to create the ' *filename.dat'* file, as explained in the Flood Modeller manual. To create the ' *filename.con'* file you can use text editor (see [Datafile Layout](/v1/docs/data-file-layout) section)

If the resulting datafile is to be viewed in a text editor then it would look like the file shown on the right column on Figure 1. In this case only one variable is being used: Conservative Pollutant.

Detailed explanation of the various entries can be found in [Datafile Layout](/v1/docs/data-file-layout).

![WaterQualityimagesimage061.jpg](https://cdn.document360.io/5074bc26-a9ef-4bf4-b1de-a5c6ce628aca/Images/Documentation/WaterQualityimagesimage061.jpg) *Figure 1. Water Quality Data viewed in a text editor.*

Datafiles such as the one above can be produced as follows:

- The other method of datafile preparation is to use a standard text editor such as Notepad or WordPad. If you choose to use an editor, it must be remembered that the data must be entered in a particular format, usually in fields of 10 characters for real numbers and 8 characters for node labels. If you inadvertently enter numbers in the wrong column, you may obtain erroneous results. Care must also be taken to avoid saving files containing ’hidden’ characters such as tabs.