Model Change Bulletin

                                   MCB#4

                           TSCREEN (dated 91303)


     The TSCREEN model code available from this bulletin board is the
upgraded version of the TSCREEN model.  The TSCREEN model has been
completely recoded in a data base language and revised to include the
following:


     1)  incorporation of terrain features that are a part of the SCREEN
         model;

     2)  a new scenario for air stripper at Superfund sites;

     3)  a number of miscellaneous editoral changes and corrections.


     Because the program has been entirely recoded, it is impractical to
update the older version by making line-by-line changes.

     This model will henceforth be identified by its name and a julian date
(i.e., TSCREEN (dated 91303)).  The model is available for downloading from
the file transfer section of the SCRAM BBS.