---
title: "Macrophytes Data Fields | Definitions"
slug: "macrophytes-data-fieldshtm"
description: "Learn about data input and the appropriate datafile format for macrophytes in the water quality solver. "
tags: ["1D river modelling"]
updated: 2022-09-22T12:20:20Z
published: 2022-09-22T12:20:21Z
canonical: "help.floodmodeller.com/macrophytes-data-fieldshtm"
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.

# Macrophytes 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 Macrophytes 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 Macrophytes 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 MACROPHYTES

Line 2 stmacn, stmacp, stmacs, rmacn, rmacp, rmacs

Line 3 rmac20, q10mac, slmxmc, plea1, pexu1

Line 4 seedmc, dethmc

Where:

MACROPHYTES = keyword

stmacn = h alf saturation constant for nitrate uptake (mg/l)

stmacp = half saturation constant for phosphate uptake (mg/l)

stmacs = half saturation constant for silicate uptake (mg/l)

rmacn = nitrogen to carbon ratio

rmacp = phosphorus to carbon ratio

rmacs = silicon to carbon ratio.

rmac20 = Productivity rate at 20C (day)

q10mac = Qvalue for macrophyte growth

slmxmc = solar radiation required for maximum productivity (J/cm/hour)

plea1 = proportion of dead material that is lost by leaching of nutrients

pexu1 = proportion of macrophyte production that is lost by exudation of nutrients

seedmc = Seed concentration (g/m)

dethmc = mortality rate constant (M) for macrophytes (day).

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Overview [Macrophytes](/v1/docs/macrophytes)