---
title: "Decay Data Fields | Definitions"
slug: "decay-data-fields"
description: "Learn about the required data input and datafile format when using decay in the 1D water quality solver. "
tags: ["1D river modelling"]
updated: 2022-08-23T05:23:16Z
published: 2022-08-23T05:23:16Z
canonical: "help.floodmodeller.com/decay-data-fields"
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.

# Decay Data Fields

## Data Input

In order to input the required information for this pollutant into the Water Quality model, the user needs to make sure that the Tab Decaying Pollutant appears in the WQ General Tab (please follow the description on the page [Preparing a Water Quality Datafile](/v1/docs/preparing-a-water-quality-datafile) for this). Then the user needs to select the Tab Decaying Pollutant and type in the necessary information for this pollutant in the fields which are shown on this Tab. Alternatively the necessary information for this pollutant can be typed in the .con file opened in a Textpad editor in the datafile format mentioned below.

## Datafile format

Line 1 DECAY

Line 2 dcyday, dcynit

Where:

DECAY = Keyword

dcyday = Daytime decay rate (day-1),

dcynit = Night-time decay rate (day-1).

---

Overview [Decay](/v1/docs/decay)