View source for Watershed Overlay

[[File:Watershed_Overlay.png|thumb|420px|right|Example of the Watershed overlay]]
The watershed overlay calculates where surface rainfall water will end up based on the [[Terrain height|DTM]] or a [[Water Overlay|water overlay's]] [[surface direction result type (Water Overlay)|direction result]]. Users can influence the created watersheds by providing indicative [[Discharge area (Watershed Overlay)|discharge areas]], which will expanded into watersheds. Furthermore, a [[Rainfall (Overlay)|rainfall overlay's]] [[Surface average direction result type (Water Overlay|surface average direction result]] can be used to calculate more realistic [[Watershed result type (Watershed Overlay)|watersheds]].
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==Usage==
The watershed overlay results can be use to:
* Debug a water system; Are the water areas used to initialize my [[water overlay]] correct or do they need adjustments
* Determine which waterways are the most important waterways in my water system, based on the size of the calculated discharge areas. 
* Help solve disputes with land owners: Does rain fall on the land of a land owner end up in water ways or does it remain on land.
* Using discharge areas as input for water simulation tools outside the Tygron engine, by combining the size of the area with the amount of rainfall it receives. 

==Considerations==
The watershed overlay calculates watershed areas based on:
* A heavy rainfall;
* Sewer is not taken into account;
* Large Forests often do not have proper discharge when not close to water ways;
* Certain computed watershed areas might not be connected to the original water system used as input, in the form as discharge areas. This in turn can help find flaws in your water system;
* Culverts are important for the connectivity of discharge areas, but often not all culverts are initially know or defined. The water connection generator tool has been added to generated culverts on a large scale based on defined input parameters;

==Modules==
A Watershed Overlay can be configured by opening the Watershed Overlay Wizard.

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==How-to's==
* [[FAQ (Watershed Overlay)|FAQ for Watershed Overlay]]
* [[How-to add and remove an overlay|Add and remove an overlay]]
* [[How-to edit an overlay legend|Edit an overlay legend]]

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