A cool tip to reduce the overall dry weather flow in InfoSWMM and H2OMAP SWMM without changing the mean dry weather flow is to do the following:
1. Make a Reduction or Increase Flow Pattern in the Operations tab of the Attribute Browser (2),
2. For example, if we want to have 85 percent of the flow use a value of 0.85
3. In the Node DWF DB Table (2) use the pattern just created (3)
4. All of the flows in the DWF table and during your simulation will be reduced by 15 percent.