Calculating downstream concentration

[Charles Ehlschlaeger]

David,

Here is a kludgy way to calculate downstream concentrations of chlorides:
You need a map of chloride discharge and a map of rainfall runoff and other
surface water inputs to the map.
Run r.watershed twice, using each of the above maps for the overland flow
option. Each run should give you a accumulation map: one for total streamflow
and one for concentration of chlorides. Use r.mapcalc to divide chloride conc.
by streamflow.

Chuck Ehlschlaeger