Demands
Demands are nodes where water is supplied to end consumers. Each
demand is associated with a constant,q¯¯ki�¯��, that denotes the
demanded volumetric flow rate, where a positive value indicates
consumption. Without loss of generality, we also allow negative flows to
represent injections (e.g., from a well). When a demand is
"dispatchable," the variablesqki∈R���∈�,i∈D�∈�,k∈K�∈�,
denote the flow consumed or supplied by each demand node. When a
demand is constant,qki=q¯¯ki���=�¯��.