Ifc Pipe Segment Ifc Distribution Chamber, Ifc Distribution Flow Control, Ifc Flow Terminal and their Types, specialisations and Pre Defined Types cover the hard infrastructure already (Ifc2x3), including open channels and possibly weirs. The free water infrastructure is Ifc Water Stratum, the natural features are Ifc Solid Stratum and the artificial landscape are Ifc Course (Ifc4.3)