External area (Water Overlay)

Icon	Key	Unit	Range	Description	Default value
	EXTERNAL_AREA	m²		The surface area of the external water body behind the breach. The larger the external water body, the more water can flow from it (or into it), and the smaller the effect of the inflow or outflow of water on the external water level. When provided with a second value, this key will also define a bottom area for the external water body, transforming its cross-section from a rectangle to a trapezoid.	n/a

External water body as a trapezoid

Notes

• If two values are provided, they represent the surface area and bottom area of the external water body, respectively. The water body will be interpreted as a trapezoidal prism, with a length set to the square root of the surface area. This will cause the water level of the external water body to change at a non linear rate.
• When a breach input area is defined, an external water body will not be created. Subsequently, the EXTERNAL_SURFACE_LEVEL, EXTERNAL_WATER_LEVEL and EXTERNAL_AREA attributes will be ignored.

How-to's

• How to add a breach with external area manually

See also

• Breach growth formula (Water Overlay)
• Breach flow formula (Water Overlay)
• Weir formula (Water Overlay)

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Water Module

Water Module

Tutorials

Overview

Theory

Benchmarks

Group

Hydrological features

Water area

Water level • Water relative

Sewer area

Sewer storage • Sewer pump speed

Inundation area

Inundation level

Aquifer

Aquifer kd • Aquifer datum

Breach

Breach height • Breach width • Breach angle • Breach coefficient • Breach speed • Breach input area • Breach level area • External surface level • External water level • External area

Rain area

Rain m

Limitation area

Limit area

Output

Object flow output • Object height output • Object datum output a • Object datum output b • Object water area output • Object width output

Related

Building attributes • Hydraulic structures •  Terrain attributes • Model attributes • Prequels • Results • Simulation data