Discrepancy in the water age results for models with short pipes and short travel times.

  Applies To 
  Product(s): WaterCAD, WaterGEMS
  Version(s): 08.11.xx.xx, 10.xx.xx.xx  
  Area:  Calculations
  Original Author: Scott Kampa, Bentley Technical Support Group

Problem

There is a discrepancy in the water age results for models with short pipes and short travel times. For instance, water age may be rounded up. For instance in a pipe next to a reservoir with a flow travel time of 3 minutes, the water age may display an age of 6 minutes.

Solution

In cases where the travel time is shorter than one tenth of a hydraulic time step (typically about 6 minutes, if the hydraulic timestep is set to one hour), you may need to adjust the water quality time step option, under Analysis > Calculation Options. Generally speaking the most accurate results will be obtained from using a water quality time step that's less than or equal to the shortest pipe flow time.

See Also

Understanding the Water Quality Time Step

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