Hydraflow Catchbasin Gutter Spread

[Anonymous]

Hi,

Anyone knows if the HGL in a catchbasin (grate inlet) affects its gutter spread?

Sometimes I found HGL is above the ground like this picture while its gutter spread is low (1.5m); sometimes I got higher gutter spread (4m) but HGL is below the pipe crown....

Thanks.

[Matt.Anderson]

No.

[Anonymous]

So the real gutter spread will be higher because the catch basin overflow is not considered in Hydraflow?

[Matt.Anderson]

Not exactly.   When an HGL value exceeds the RIM elevation, the calculations do not subtract flow from the underground pipe system.