Update and Availability of the Two-dimensional Method-of-Characteristics Solute Transport Model Program for Prime Computers. UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY RESTON, VA. 22092 In Reply Refer To: November 28, 1983 EGS-Mail Stop 411 GROUND WATER BRANCH TECHNICAL MEMORANDUM NO. 84.01 Subject: GROUND WATER--Update and Availability of the Two- dimensional Method-of-Characteristics Solute Transport Model Program for Prime Computers. The attached set of "update notes" documents a number of revisions that have been made recently to the two-dimensional solute- transport model documented in Techniques of Water-Resources Investigations, Book 7, Chapter C2. The modified code will generally yield more accurate results, and it is recommended that all users of this model modify their source code accordingly. The updated source code of the subject model runs successfully on Prime if it is compiled with the F77 compiler using no options. The -F option only slightly increases the accuracy, but also increases the CPU time by over 5 percent, so it is probably not necessary or desirable for most problems. Our initial experience in using this program on the Reston Prime indicates that if the decimal point is omitted from a G-format input data field, as is used for much of the input data, then the Prime will not fill in trailing blanks as trailing zeros; consequently, it will place the decimal at a point other than anticipated. Until the Prime telecommunication network becomes operational, copies of the updated source code card images can be obtained by running the following job on the USGS Re-1 Amdahl computer in Reston, Virginia: //----JOB---- /*JOBPARM CARDS=800, LINES=5 /*ROUTE PUNCH RMTxxx //PROCLIB DD DISP=SHR, DSN=SWB.PROCLIB // EXEC CARDPCH, UDS='VG46ANN.MOCP.FORT/', LIST=1 // The xxx should be replaced by the Amdahl remote-terminal number of the Prime site at your respective Districts. This job sends punched-card images to the Prime RJE facility at the specific site. Installation-specific procedures should be followed to receive the card images and move them to an appropriate user directory (refer to DIS Newsletter, Vol. 1, No. 6, November 1983) or consult your system administrator. The source code also could be sent by means of TSO or WYLBUR. If you have any trouble moving the source code or compiling, loading or running the computer program, please contact Ren Jen Sun of the Ground Water Branch, on FTS: 928-6904. (s) Eugene P. Patten Chief, Ground Water Branch Attachment