| Product(s): | SewerGEMS, CivilStorm |
| Version(s): | 10.02.01.04 and earlier |
| Area: | Calculations |
Problem
When using the Explicit (SWMM) solver and changing the calculation options Start Time, a graph of flow or sanitary load becomes shifted and does not match up with the start time of the pattern itself (assigned to the sanitary loads).
You may also notice different behavior depending on whether or not you are using daily / monthly multipliers in the pattern, and whether there is only a single pattern load or multiple pattern loads. For example one for weekdays and another for weekends.
Example with pattern start time set to 12 AM but calculation options start time set to 4 AM:
Solution
This is a known issue (reference #1028077) that has been resolved in a patch to version 10.02.01.04. The fix was to change the program so that it exports the start date and times to the Date and Time fields of the SWMM time series that the program uses to define the flow patterns. In other words, it makes them absolute patterns, so that the calculated results match the expected pattern and start time.
An additional fix was made in a patch to version 10.02.03.03 which addressed other related issues with using daily/monthly multipliers and using multiple pattern loads per manhole.
To get the fix, either upgrade to a newer version when available, or contact Technical Support for the latest cumulative patch set.