Weir (Water Overlay)

Weirs are effectively small dams in the water, and allow water to flow from a water body with a higher water level to a lower water level. Any water exceeding the height of the weir can flow over it, increasing the throughput as the water level increases. Strictly, water can flow over the weir in either direction.

A weir is a line-based construction.

Icon	Key	Unit	Range	Description	Default value
	WEIR_HEIGHT	m + datum	-10000 to 10000	The height of the weir. Water can flow past the weir when the water level exceeds the weir's height.	n/a
	WEIR_WIDTH	m	0 to 10000	The width of the weir.	5
	WEIR_ANGLE	geo angle (0-360°)	-1.7976931348623157E308 to 1.7976931348623157E308	The top down orientation angle of the weir.	0
	WEIR_COEFFICIENT	coefficient	0 to 10000	The flow coefficient related to the shape of the weir.	1,1

Notes

• If a weir is placed in a waterway, and the waterway is not otherwise interrupted, water might be able to flow past the weir via the waterway itself. In order to obstruct the waterway, one of two options can be chosen:
  • Define the weir angle, in which case the Tygron Platform will automatically raise the DEM in the simulation based on the position, width and angle of the weir.
  • Manually raise the terrain height using the terrain height tool or applying a terrain height geotiff.
• Weirs can be read in as a point. The Tygron Platform will precompute how the weir should be modeled as a line.

How-to's

• How to correct multiple constructions on the same location
• How to correct weir, pump, or culvert drawn as point
• How to correct a construction in an uninterrupted waterway
• How to correct a construction at the edge of the project area

See also

• Weir formula (Water Overlay)

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Water Module

Water Module

Tutorials

Overview

Theory

Benchmarks

Group

Hydraulic structures

Inlet

Inlet q • Inlet area • Inlet capacity •  Lower threshold •  Upper threshold • Inlet underground

Pump

Pump q •  Lower threshold •  Upper threshold • Pump angle • Pump capacity • Pump area

Culvert

Culvert diameter • Culvert rectangular height • Culvert threshold • Culvert n

Weir

Weir height • Weir width • Weir angle • Weir coefficient • Weir target level

Sewer overflow

Sewer overflow • Sewer overflow speed

Drainage

Drainage q • Drainage datum • Drainage active • Drainage overflow threshold

Output

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

Related

Building attributes • Hydrological features •  Terrain attributes • Model attributes • Results • Simulation data