I am a student working with Hydrological models. Within these models we can route water across a DEM (within a delineated watershed or just within an un-delineated DEM) using many different flow routing algorithms: D8, MFD (sometimes FD8), Rho8, DEMON, D-Inf, and so on, with different variations within even the ones I listed possible (original MFD vs. MFD with a power term).
But, when working within a delineated watershed, a flow routing algorithm (primarily the D8) has already been applied to get the flow directions grid - typically the first step in a delineation.
Has there been any research looking at the difference between delineations performed on flow directions grids created using the other algorithms? I know since these other algorithms allow multiple flow directions, that it might be difficult to visualize this data (unless there is some compounding into one value) - and that that alone might make it impossible.
It doesn't seem like the delineations would be any different - if point y is in the watershed of pour point x, water will flow from point y to pour point x, whichever way it may get there. The flow may be split into an infinite number of paths (infinite dispersion), but they will still all end up at point x, right? So even though D8 might not be perfect for predicting actual flow paths, it should produce the same delineation as any other, right?