A normal flow channel defined by its length, bed resistance and hydraulic properties. The channel can wet and dry, however, for overbank areas (eg. tidal flats or floodplains) gradient (G) channels should be used. For steep channels that may experience supercritical flow, use S channels.
Note: leave Channel_Type blank to specify a normal channel.
Bridge
B
A bridge structure. See Section 3.14.4.2.
Circular Culvert
C
A pipe or circular culvert. See Section 3.14.4.2.
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F
Reserved (do not use).
Gradient
G
Similar to a normal channel, except when the water level at one end of the channel falls below the channel bed, the channel invokes a free-overfall algorithm that keeps water flowing without using negative depths. The algorithm takes into account both the channel’s bed resistance and upstream controlled weir flow at the downstream end.
Gradient channels are designed for overbank areas such as tidal flats and floodplains. The upstream and downstream bed invert attributes must be specified to define the slope of the channel.
Rectangular Culvert
R
A box or rectangular culvert. See Section 3.14.4.2.
Similar to a normal channel, except switches into upstream controlled, friction only mode (ie. no inertia terms) for higher Froude numbers (see Froude Check). This allows steep flow regimes such as super-critical flow to be represented. See also Froude Depth Adjustment.
Upstream and downstream bed invert attributes must be specified to define the slope of the channel.
Note: This feature was introduced in Build 2002-08-AC and has been tested and trialled on a number of models at the time of writing (also see discussion for 2D domains in Section 3.14.3).
Weir
W
A broad-crested weir structure. See Section 3.14.4.4.
