**V-Notch Weir flow** is calculated using the following formula:

where

*C _{d}* = Coefficient of Discharge

*vang* = internal angle of the V (degrees)

g = acceleration due to gravity (9.81 m²/s)

*H* = height of water above weir invert

When the downstream level is above the crest level the software will use the Villemonte equation to simulate the submerged nature of the flow:

where:

Qs = Submerged Flow Rate

Q = Free-flow rate at H

Yd = Depth downstream

H = Water Depth at point of measurement

Note: Discharge exponent of 2.5 (5/2) used for V-Notch weirs.

## V-Notch Weir: Specifications

**Angle of V **- Enter the angle of the V in degrees.

**Coefficient of Discharge** - Enter the discharge coefficient of the weir. A default value of 0.59 is given.

**Invert Level **- The invert level of the Weir.