Area of a Manhole in #SWMM5

The default area of a manhole is used if the inverts of the connecting links are all above the invert of the node:

1.     Invert of the node to the Invert of the lowest connecting link, the area of the manhole is 1.2 square meters or whatever the user defines,

2.     If the water surface is between the invert of the lowest connecting link and the soffit of the highest connecting link then the area of the node is ½ of the area of the connecting links

3.     If the water surface of the node is above the soffit of the highest connecting link then the area of the node is zero and the program tries to balance the flow into and out of the node so the total flow is zero