I would like to connect two demand sites, one upstream (1) of the other (2); deliveries from site 1 to 2 should be shorted if demands to site 1 are shorted.

What I am noticing with WEAP is that no matter how much the demands to site 1 are shorted, the deliveries to site 2 from site 1 are always complete and don’t reflect the shortage. Should this be the case or is there a way to work around it?

Yes, WEAP can model this situation. You can reuse wastewater directly by connecting the demand sites with a transmission link. When you do this, the downstream demand site should have a lower priority than the upstream demand site. Any water not consumed by the upstream demand site is available to supply the downstream demand site.

Jack