SWRRB Hydrolological Model & GRASS & ARC/INFO

[C.E.Stocks]

Dear All,
   I am doing some research on integrating hydrological models
into raster based GIS. I was wandering whether any GRASS users have 
had  experiences with using the SWRRB model (Simulator for Water
Resources in Rural Basins) and whether any body knows of a source 
from which this model and its supporting documentation may be 
acquired. 
 
   Since I last wrote to this list I have programmed TOPMODEL and 
AGNPS into the cell based modelling language (map algebra) of 
ARC/INFO. I may do the same with GRASS using r.mapcalc and shell 
scripts in order to provide a basis for comparison. However, I think 
that ARC/INFO is easier to use.  

   I am actually trying to find out whether standard general purpose 
GIS are any good for hydrologically oriented modelling and if so, 
how best they may be applied. My ARC/INFO AGNPS and TOPMODEL
emulate the FORTRAN versions of these models quite well, but are very 
slow to execute because their simulation algorithms are in command macros and 
not complied.  

   The ARC/INFO TOPMODEL predicts spatially distributed 
saturation excess overland flow and lumped base flow, I am also 
working on an infiltration excess overland flow algorithm. I have 
developed spatially distributed hill slope runoff hydrographs to 
predict flow entering river channel segments and incorporated a 
constant velocity kinematic wave channel routing method. The ARC/INFO 
AGNPS just does more or less what the FORTRAN version does.

   I would like to have ago at implementing the SWRRB model next and 
also the ANSWERS model as well. If any body would like to  comment on 
what I have been up to, or have any similar experiences they may wish 
to share with me  please let me know. 

Cheers,

Chris Stocks

p.s.  If you know anything about the SWRRB model please pass the 
information on, I also apologise to those GRASS users who don't like 
hydrological modelling / ARC/INFO messages cluttering up their e_mail 
list.