[GRASSLIST:549] surface runoff distance

[wouter buytaert]

Hello,

I'm doing some hydrologic modelling and would like to extract from a DEM
the distance of all pixels to a river network downslope (which I have as
a raster map too). So it is not the shortest distance I need, but the
distance the water flows over the surface.

Is there anyone who nows the easiest way to do that?

thanks,

Wouter Buytaert