Watershed Overlay

Example of the Watershed overlay

The watershed overlay calculates where surface rainfall water will end up based on the elevation model or a Water Overlay's direction result. Users can influence the created watersheds by providing indicative discharge areas, which will expand into watersheds. Moreover, a direction prequel overlay, such as a rainfall overlay's surface avg direction result can be used to calculate more realistic watersheds.

Usage

The watershed overlay results can be used 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 rainfall 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 Platform, 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 they are 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 generate culverts on a large scale based on input parameters;

Module

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

Watershed Module

Tutorials

Overview

Theory

Benchmarks

Result types

The watershed overlay can provide the following result types:

Icon	Result type	Unit	Mode	Description
	WATERSHEDS	Integer		The integer ID of the calculated watershed. NO_DATA if no watershed area was calculated for that particular cell.
	DISCHARGE_AREAS	Integer		The initial Discharge Areas and propagated to water cells by neighbors and culvert-connections.
	DIRECTION	geo angle (0-360°)		The direction to which rain water would flow.
	BASE_TYPES	Nominal		Categorization of the individual cells based on how they are processed by the watershed model, displaying which cells are considered to be specific features.

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Demo projects

• The project Demo Watershed can be explored to see how a Watershed Overlay based on a Rainfall Overlay can contribute to debugging a watersystem.

How-to's

• FAQ for Watershed Overlay
• How to add and remove an Overlay
• Edit an overlay legend

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Watershed Module

Watershed Module

Tutorials

Overview

Theory

Benchmarks

Group

Result type

Result types

Base types • Direction • Discharge areas • Watersheds

Related

Result type • Model attributes

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Overlays

Categorization

Grid • Parent • Result Child • Result Parent • Result type

Default

City

Administrative

Ownership • Ownership Grid • Zipcodes • Zoning • Neighborhoods • Municipalities • Vacancy

Environmental

Heat Stress • Traffic Density • Traffic Noise • Traffic NO2 • Livability • Aerius

Water

Rainfall • Flooding • Groundwater • Subsidence • Watershed • Waterwijzer

Raster Calculation

Average • Combo • Distance • Sight Distance • Travel Distance

Geo Data

Area • Attribute • GeoTIFF • WCS • WMS • Image

Topography

Digital Surface Model • Digital Terrain Model • Underground • Function • Source

Network

Network Distance • Network Overview • Network Ownership