Users may assign a prescribed flux boundary condition along the polyline by selecting the ‘Prescribed Flux’ radio button and choosing one of the units of input: 1) ‘Per unit length’ – prescribed flux per unit length (square meters per day) along a polyline (e.g., in the case where stream thickness is negligible), which is the default setting; 2) ‘Total’ – total prescribed flux across the entire polyline-aquifer interface ; and 3) ‘Per unit area’ – the prescribed flux per unit area along the polyline. Note that all three options apply for steady conditions (i.e., no changes in flux with time) and spatially-constant flux along the polyline.
To assign time-dependent (total) prescribed flux boundary conditions, leave the ‘Prescribed Flux’ radio button selected, but also check the radio box next to ‘Transient’. Then click the ‘Transient’ button to open the sub-menu for editing transient flux data