---
title: "The Urban Outfall Node | Technical Reference"
slug: "the-urban-outfall-node"
description: "Learn about the urban outfall node: downstream boundaries for the network in the case of dynamic wave routing. "
tags: ["1D urban modelling", "junction"]
updated: 2022-08-26T13:48:48Z
published: 2022-08-26T13:48:48Z
canonical: "help.floodmodeller.com/the-urban-outfall-node"
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.

# The  Urban Outfall Node

**Outfall** nodes are downstream boundaries for the network in the case of Dynamic Wave routing. For the other versions of the solver, Outfall nodes will behave in the same way to [Urban Junction Nodes.](/v1/docs/the-urban-junction-node)

External [Urban Inflow](/v1/docs/1d-urban-flow) can enter the system at Outfalls. Outflow from an Outfall can either be lost from the system, or routed onto an [Urban Subcatchment Node.](/v1/docs/the-urban-subcatchement-node)

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

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#### Rules of Outfall nodes

Only a single inflow [Conduit Link](/v1/docs/the-urban-conduit-link) can be connected to an Outfall node. No outflow pipes (links) can be connected to an Outfall node.

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#### Outfall label/name

The Outfall node name by default will be provided by parameters setup in the [Urban Model Defaults](/docs/Urban_Model_Defaults.htm) menu.

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#### Coordinates

The x and y coordinates of the Outfall node are shown in these fields. These values are automatically populated based on the node location on the map.

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#### Optional descriptors

**Description**

This field allows for an optional text description. The field will be blank by default.

**Tag**

This field allows for an optional text tag, to allow you to categorise units. The field will be blank by default.

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#### Inflows

External inflows can be optionally specified for Outfall nodes.

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#### Treatment

Addition of pollutants is not currently available within the software. If your model already contains defined pollutants, these will be unaffected, however you will not be able to access the pollutant editor form.

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#### General node parameters

**Invert elevation**

The invert elevation of the Outfall is provided in this field. By default this value will be provided by parameter setup in the [Urban Model Defaults](/docs/Urban_Model_Defaults.htm) menu.

**Tide Gate**

This will incorporate a flapped gate on the outfall, preventing backflow. The option is set to NO by default.

**Route To**

This option allows for the outfall to discharge onto a subcatchment (i.e. a specified [Urban Subcatchment Node](/v1/docs/the-urban-subcatchement-node)). The field is blank by default.

**Type**

This specifies the boundary condition (specifically, the stage) in the Outfall node:

FREE - the stage will be determined by the minimum of the critical and normal flow depths in the connecting conduit. This is the default and requires no further parameters to be specified.

NORMAL - the stage will be determined by the normal flow depth in the connecting conduit. This option requires no further parameters to be specified.

FIXED - sets the outfall stage to a fixed value, in which case the value must be provided in the **Fixed Outfall : Fixed Stage** field.

TIDAL - sets the outfall stage to a table of tide elevation (against time of day) data, in which case this data must be provided in the **Tidal Outfall : Curve Name** field.

TIMESERIES - sets the outfall stage to a timeseries of stage data, in which case this data must be provided in the **Time Series Outfall : Series Name** field.