This refers to an open channel that has the same cross-section and bed slope throughout. This may have a rectangular, trapezoidal, semi-circular or other cross-sectional shape. Note that rectangular and triangular shapes are special cases of the trapezoidal shape.

In DRAINS the term is used to define man-made trapezoidal channels. Strictly speaking, however, a natural channel with an irregular shape is prismatic, as long as the cross-section and bed slope are constant along its length.

Details of prismatic channels are specified in a property sheet.

Following a run, flowrates through a channel and water levels at its ends can be viewed in the Main Window display. Options for displaying more detailed results are given in the Pop-Up (right mouse button) menu.  View Cross Sections provides a display showing the channel cross section and the peak water levels at each cross section entered.

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