I am working on a groundwater model here in New Mexico. One important component is the southern and western boundaries of the model, where steep canyon walls seep water from the volcanic aquifer, substantially contributing to river flows. I intend to model the boundary condition at the river with STR2, such that recharge and discharge interactions between groundwater and the channel can be calibrated. However, I'm not sure how to handle the canyon walls. Adjacent flooded cells, while conceptually accurate, I believe to not deliver their discharge down (topographic) gradient. I'm interested in the seepage face package, but I am not seeing much documentation or discussion on it and many folks are referring to it as a boundary condition in itself. Can anyone clarify what scheme might work for this, and perhaps share a couple of links? Thank you!