Question: When a node goes into surchage with the ponding flag on, is
head being calculated on the system based upon the ponding depth at the
node? Answer: When the HGL rises above the Spillcrest of a hydraulics
(Extran) node with ponding on in XP-SWMM the head on the system does
include the ponded depth.

Question: Junction Defaults in the Extran Job Control the ponding area
equation is defined as:

ponding area = (constant) e ^ (ponding depth)

where the ponding depth is entered as a constant. Please clarify this
for me, as the equation would seem to make more sense if the exponent
was a variable (variable depth).

Answer: The equation is actually: ponding area = coefficient times e ^
(exponent times ponded depth)

Therefore it is variable since the user can enter a value for exponent.
Only a value of zero would make the area constant for a given depth.
Basically the area increases as the depth on the surface increases.

Anthony Kuch