Water quality/GIS models

[GRASS 4.0]

I see references to answers, and agnps
as well as topmodel - all of these are 
variations of hydrologic modals aimed
at water and sediment flow (agnps does
some other things as well) but I see no 
references to water quality/GIS models 
that deal with pesticide fate.

Are there any? 

Has anyone created some
modules for preexistent models that
model pesticide movement too?

I also heard at one time that someone
was trying to interface CREAMS with 
a GIS.  Are there ant references
to this out there?


thanks in advance.

Keith M Mitchell
University of Illinois
Dept. of Ag Engineering