Breach (Water Overlay)

A Breach area can be used to simulate a breach in a levee or dam. It is identified via the BREACH_HEIGHT attribute. Water flowing through the breach originates from a body of water. This body of water can be defined as an input area in the project or a conceptual external water body existing outside the project area. Water can flow through the breach from the input water body to the defined Breach area, and vice versa.

Attributes

Icon	Key	Unit	Range	Description	Default value
	BREACH_HEIGHT	m + datum		The new terrain height at the location of the breach.	n/a
	BREACH_WIDTH	m		The initial width of the breach.	10000
	BREACH_ANGLE	geo angle (0-360°)	-1.7976931348623157E308 to 1.7976931348623157E308	The angle at which water flows out through the breach.	n/a
	BREACH_COEFFICIENT	coefficient		The flow coefficient related to the shape of the breach.	1.37
	BREACH_SPEED	m/s		The critical speed factor in the breach width grow-formula (e.g. 0.2 for sand and 0.5 for clay).	n/a
	BREACH_INPUT_AREA	ID of an Area		The Area item representing the influx area for the breach.	none
	BREACH_LEVEL_AREA	ID of an Area		The Area item representing the downstream water level measurement area for the breach.	none
	EXTERNAL_SURFACE_LEVEL	m + datum		The height of the bottom of the external water body behind the breach. The lowest level the external water level can lower to.	0
	EXTERNAL_WATER_LEVEL	m + datum		The water level of the external water body behind the breach. The initial level the water level is set to.	0
	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

Overlay attributes

Icon	Attribute	Unit	Range	Description	Default value
	BREACH_MEASUREMENT_DISTANCE_M	m		Distance from the breach area to the automatically placed measurement point for the downstream water level of the breach, in the direction of the breach.	100

How-to's

• How to add a breach with external area manually
• How to add a breach with input area manually
• How to import a breach with input area
• How to set dynamic breach height
• How to visualize multiple sequential breaches (Water Overlay)
• How to inspect breach output attributes of an overlay using the measurement tool

Videos

Modeling breach growth

See also

• Breach model (Water Overlay)
• Elevation model (Water Overlay)
• Breach growth formula (Water Overlay)
• Breach flow formula (Water Overlay)
• Object width output (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 width output

Related

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