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In SewerGEMS or Civilstorm, why do I see 0 (zero) overflow for a manholeduring a timestep in which the HGL at that manhole is above the rim?Problem Number 32696Version: 08.09.025.00 and 08.09.26.17
First, make sure you do not have a bolted cover. If you do not, thenthis is likely caused by tailwater. In version 08.11.00.08 and below,SewerGEMS and CivilStorm cannot calculate overflow from backed up waterdue to tailwater. It can only calculate overflow from upstream water.If you have version 08.11.01.21 of SewerGEMS, you can overcome thisissue by increasing the LPI coefficient in the advanced calculationoptions. For example, try a value of 12.0. This allows the calculationengine to have more dynamic effects and account for the overflow frombackwater. Note that this will only work for circular conduits.