Initial flows in conduits may be input by the user using the conduit dialog. For each conduit, EXTRAN then computes the normal depth corresponding to the initial flow. Junction heads are then approximated as the average of the heads of adjacent conduits for purposes of beginning the computation sequence.
The initial volume of water computed in this manner is included in the continuity check. A more accurate initial condition for any desired set of flows may be established by letting EXTRAN "warm up" with the initial inflows and restarted using the "hot start" feature explained earlier in the manual.
Initial heads at junctions may be input by the user with the conduit dialogs. The model does not estimate the initial conduit flow if the conduit flow is entered as zero. Initial heads at junctions with a sump orifice are increased by 0.96 times the equivalent pipe diameter of the orifice at the start of the simulation.