Hi, I am new to FESWMS as well and am having the same error. I have set my upstream input boundary to ##, but it appears not to recognize any flow since my Zw is -999 for all nodes at the boundary. I have set the intial conditions to have a water surface elevation equal to the highest elevation in my model. !ERROR - Total conveyance is zero in boundary cross section "1". Cross section nodes: ======================================================= N NpID Bcode Zw Zb H ----- --------- --------- --------- --------- --------- 18 0 0 -