  Kinetic self-avoiding trails are introduced and used to generate a substrate
of randomly quenched flow vectors. Sandpile model is studied on such a
substrate with asymmetric toppling matrices where the precise balance between
the net outflow of grains from a toppling site and the total inflow of grains
to the same site when all its neighbors topple once is maintained at all sites.
Within numerical accuracy this model behaves in the same way as the
multiscaling BTW model.
