I want to input, into BC head-constant nodes a max. flow-rate constraint = 0 m3/d and a min. flow-rate = -5 m3/d. So I select the nodes where the constraints are to be applied and the I go to the Data Panel, and in the Hydraulic heads BC I open the menu and click on ad parameter,&#160; I then click in min. flow-rate constraint and, as in your documentation files on this issue, I double click on the value in the editor toolbar. No change happens in the units (which should be by them m3/d) once we are applying a constraint to a constant head BC. If I click on the green checkmark, what happens is that the value in the editor toolbar enter as my BC and when I do the Inspection it comes as unconstrained.&#160;<br> How, then can I enter constraints? Must I define on the Problem settings that the model is constrained?<br> <br> <br> By the way, as soon as I click on the green checkmark, the option of the constraint I selected previously, simply disappears from the BC menu Add parameter. This means that if I try to apply it to an area of my river network and then go to a completely different area of the model, and select a new set of nodes, if I go to the Add parameter, that type of constraint is no longer available. How can I overcome this?