Thanks for the help everyone. It turned out to be an issue with main diameter and cross-connections. With some line upsizing and valving, pump seems to be working fine. @bimr and @jonr12, thanks for the tips, I'll keep them in mind as we progress.
To clarify, I was thinking the pump TDH would equal target HGL, minus ground elevation at the highest point in the low pressure zone, minus static contribution.
I'm working with a small town who is under consent order from the state DEQ for low system pressures. They have a 72' tall ground storage tank, and must keep it at a minimum level of 63' to have even serviceable pressures in the vicinity - when hydrants are opened for fire protection or...
You can just select the reservoir tool and click on the junction you want to replace. WaterCAD will prompt you to confirm if you want to morph the junction to a reservoir, so just hit "Yes".
