Applies To
	Product(s):	SewerGEMS, CivilStorm
	Version(s):	08.11.XX.XX
	Area:	Other
	Original Author:	Dan Iannicelli, Bentley Technical Support Group

Problem

The following user notification appears after computing:

"The convolution time step is too large for the unit hydrograph resulting in 0 volume under the curve."

What does this mean? The catchment is using the SCS Unit Hydrograph for the Unit Hydrograph Method, with "Default curvilinear" as the SCS Unit Hydrograph Method.

Problem ID#: 80451

Solution

The reason for this Convolution Error is likely because there is no value set for Area in your Catchment Properties.

To remedy this:

1.) Go to the Catchment properties by double clicking on the catchment.

2.) Set the Area (User Defined) to some value. Or set 'Use Scaled Area?' to true.

3.) Make sure all values are set correctly in the Catchment Properties.

4.) Recalculate.

5.) This Error will no longer prompt as a User Notification.

If you have multiple Catchments without data set correctly, you can edit all of the Catchment properties at once. To do this go to View > Flextables > Catchment Flextable