SWMM 5 St Venant Solution - 3 Depths, 4 Cross Sectional Areas in a Link but one Mid Point Flow · March 26, 2015 SWMM 5 St Venant Solution - 3 Depths, 4 Cross Sectional Areas in a Link but one Mid Point Flow from Robert Dickinson on Vimeo. SWMM 5 St Venant Solution - 3 Hydraulic Radius's, 5 Terms in the St Venant Equation from Robert Dickinson on Vimeo.