Subject: Qfull in SWMM 5 for various levels of y/yFull in a Circular Pipe
Here is a table that shows the value of Q/Qfull for various levels of y/yFull or d/D in SWMM5. The full flow if you loop off the top of a circular pipe at the 0.83 level would be about 1.01 times Qfull for the whole pipe. Figure 1 shows how the flows are calculated at various values, Table 1 and Figure 2 show the values of a/aFull, r/rFull and q/qFull for various values of y/yFull.
Figure 1. How Qfull and Qmax are calculated in SWMM 5 based on the roughness, slope and a lookup table for area and hydraulic radius for a circular pipe.
Figure 2: A/Afull vs y/Yfull for a circular pipe
Table 1. Table of y/yFull and Q/Qfull based on a/aFull and r/rFull