Stage Discharge

When this button is selected, XPRafts expects level/discharge co-ordinates to define normal outflow discharge relationships. Level vs. Discharge data is only required if the 'Stage Discharge' option is selected. Click on the Coordinates button to open the data dialog window, below.

US Water Level. Basin Water Level (m). The first water level must also be the lowest level in the reservoir/basin. Values in this column are interpreted as ABSOLUTE levels if the first level equals the Basin Invert Datum Level. Otherwise, the first level MUST equal zero and values are interpreted as levels RELATIVE to the Basin Invert Datum Level.

Outlet Discharge. Discharge through normal conduit outlet or total discharge as defined. It is possible to use the level / discharge table to define the normal outlet discharge relationship then add a spillway discharge relationship by way of equations or rating table under spillway options. Discharges must be non-negative.

Stage/Discharge Factor

Fractional multiplier of stage/discharge values


When the culvert outlet radio button is selected, outflows calculated by appropriate equations.

Select the outlet geometry:

Pipe Diameter. Pipe diameter in meters (m).

Orifice Diameter. Orifice diameter in meters (m). Entrance loss, Slope, Length, and Mannings 'n' are ignored.

Box Culvert. Data required for box culverts: height and width in meters (m).

Entrance Loss (Ke) Coefficient

Culvert entrance loss coefficient default equal to 0.5.

Culvert Slope

Slope of normal outlet conduit under embankment (%).


Normal outlet pipe length under embankment (m).

Manning's Roughness

Manning's roughness of culvert conduit.

No. of Conduits

Number of conduit barrels or orifices. All barrels are assumed equal.