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<br />I <br />002554 <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />21 <br /> <br />reservoir operators. Each water user has a list of <br />potential water sources that includes: direct <br />diversions, groundwater pumpage, imports, or reservoir <br />releases. <br /> <br />All direct diversions are simulated to conform to the <br />basin-wide priorities according to the prior- <br />appropriation doctrine. stream depletion from <br />groundwater pumpage and return flow from excess <br />irrigation applications and canal leakage are simulated <br />by using groundwater response functions. Model outputs <br />can be obtained in the form of printed reports or <br />graphical displays. Comparisons can be made to previous <br />model runs. <br /> <br />2. ses Revisions to the USGS Model <br /> <br />Access to the USGS model, which was located on the USGS <br />mainframe computer system, was not readily available to <br />the SCS planning staff. It was decided to move this <br />model to a SCS computer system. The systems available <br />included an AT&T 3B2-400 system operating under UNIX or <br />an AT&T 6386 system operating under DOS. <br /> <br />A listing of the FORTRAN source code and input data <br />files were obtained from the USGS. This FORTRAN code <br />had been compiled on a mainframe computer system. The <br />FORTRAN code was loaded on the AT&T 3B2-400. This <br />system did not have sufficient memory to compile and run <br />the program. <br /> <br />The AT&T 6386 system had the memory capacity to run the <br />program if the available extended memory could be <br />accessed. The original FORTRAN code would not compile <br />on the AT&T 6386 system because the extended memory <br />could not be accessed. A review of the existing FORTRAN <br />compilers indicated that LAHEY 77 FORTRAN using anOS386 <br />memory manager program could access the extended memory <br />in the DOS system. <br /> <br />The USGS FORTRAN source code was rewritten using LAHEY <br />77 FORTRAN. The graphical output feature of the <br />original program was not converted. The revised model <br />will display the results in tabular form on the computer <br />monitor or the output files can be printed. No <br />provision in the program has been made to compare the <br />model outputs with previous runs. Printed results from <br />model runs of the revised program were compared to runs <br />of the USGS model using the same data file. Differences <br />in the two programs were not significant. <br />