Message-ID: <1914695289.10326.1597450979769.JavaMail.HILLINCONF\$@HILLINCONF> Subject: Exported From Confluence MIME-Version: 1.0 Content-Type: multipart/related; boundary="----=_Part_10325_204857958.1597450979768" ------=_Part_10325_204857958.1597450979768 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Content-Location: file:///C:/exported.html Runoff Weir Diversions

# Runoff Weir Diversions

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In Runoff, a weir is a control structure at the bottom of a conduit which affects = the outflow characteristics of the conduit. Data must be entered for both t= he weir and the conduit.

Runoff mode supports two d= ifferent types of weir diversions: Rectangular, and V-notched weirs.

## Rectangular Weir

This option uses a broad-c= rested weir control structure at the bottom of the conduit. A weir equation= is used to control the outflow from the conduit instead of Manning's equat= ion. =

The weir is defined in ter= ms of its:

Weir Length (G2 - SPILL).&nbs= p;Length of rectangular broad-crested weir (eg. width of spil= lway), ft [m].

Weir Height (G2 - WELEV).  Height of weir crest from bottom of conduit, ft [m]. = The weir height may be used to store water in a conduit.

Weir Discharge Coefficient (G= 2 - WDIS). Discharge coefficient of the weir. Note that = this parameter is shared for both rectangular and triangular weir options.<= /p>

Conduit Data must also be entered.

Q =3D = C . L . (H - Hc)^1.5

where:

Q =3D = outflow, cfs [cms]

C =3D = weir coefficient, ft^0.5/sec [m^0.5/sec]

L =3D = weir length, ft [m]

H =3D = hydraulic head, ft [m]

Hc =3D= weir crest depth, ft [m]

## V-notched Weir

This option uses a V-notch weir control structure at the = bottom of the conduit. A weir equation is used to control the outflow from = the conduit instead of Manning's equation. The triangular opening of a V-no= tch weir is assumed to have no upper limit. The weir is defined in ter= ms of its:

Angle (G2 - SPILL). V-notch angle, in degrees, of the notch opening in a V-notch weir= .

Height. We= ir Crest height of the weir before flow over the weir, ft [m].

Weir D= ischarge Coefficient (G2 - WDIS). Discharge coe= fficient of the weir. Note that this parameter is shared for both rectangul= ar and triangular weir options.

Conduit= Data must also be entered.

The equation used for V-no= tch weirs is:

Q =3D = C . TAN(A/2) . (H - Hc)^2.5

where

Q =3D = outflow, cfs [cms]

C =3D = weir coefficient, ft^0.5/sec [m^0.5/sec]

A =3D = angle of notch (angle of opening), degrees

H =3D = hydraulic head, ft [m]

Hc =3D= weir crest depth, ft [m]

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