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SUMMARY
The original WIRSOS model had many good features that allowed it to model water rights within the state of Wyoming. WIRSOS also had weaknesses, one of which was the modeling reservoirs. It was the purpose of this thesis to improve the operation of the WIRSOS model in several aspects including reservoir operations. To achieve this objective, reservoir storage, project rights handling, reservoir rights handling, and releases from a reservoir were modified in the model. These modifications are an improvement to the operation of WIRSOS where reservoirs are concerned. In addition to modifying WIRSOS, the program was separated into subroutines and the previous modifications were incorporated into the current model. An improved modular program for river system operation simulation was created which allows for ease of change where special problems arise in modeling a river system.After WIRSOS was separated into subroutines, previous modifications and additions to the model were incorporated into the program. These improvements affected every subroutine in the model to some degree. A few subroutines remained relatively unchanged; however, a few were altered significantly. In addition to altering existing subroutines, twenty additional subroutines were added to enhance WIRSOS. Eight of these subroutines were previous modifications that were partially or totally altered or expanded to handle more information and made into subroutines. The other twelve are totally new subroutines.
The first eight subroutines are: RRDIS which removes water, released from a reservoir, from the reservoir rights accounts; HEADER which controls the operations of the interactive user interface; INPUT which reads in the input data file names and locations; OUTPUT which reads in the output file names and locations; MDLRUN which reads in the model run information; HEAD which writes the header, the time, and the date for each run to the output files; EFFNCY which reads in the monthly efficiency tables; and TWELVE which sorts Tapes 12 and 13 by permit number, month, and year before writing the information to another output file. The last twelve are: PRICHK, RSVCHK, and IFRCHK which check the rights data files to determine if the rights were entered in the proper sequence; STACHK which checks the station data file to determine if the stations were entered in the proper order; JPRCHK which checks if any rights were entered that are not downstream from their associated reservoir; DIVCHK which checks and computes water exchanges; SCNDRESV which processes a project rights request for water from a second reservoir; RRBALNC which determines the percent of the total permitted reservoir volume that each reservoir right controls and the number of reservoir rights associated with a reservoir; RESMIN which determines the amount of water needed from a reservoir to satisfy the minimum release requirement from a reservoir; MINRSRL which releases the water needed to satisfy the minimum release from a reservoir; OVERSUP which stores an extreme supply of water in the river system in the reservoirs on that system; and TOR which reads the information written to temporary file Tape 23 by EOM and sorts that information by right, month, and year before writing the information to Tape 19. Finally, the last file added was WIRSOS5.FC which contains the variables declared and used in WIRSOS5.
Though the model runs well, there are a few items that should be kept in mind during its operation. First, each reservoir must have a station above and below the reservoir station, so that the minimum flow below a reservoir can be calculated. Second, any junior project right that calls on two reservoirs must be physically downstream from both reservoirs. Third, an integer value greater than zero must be entered for the first year of model operation. Finally, any existing model that is to be ran with the current version of the program must have an extra line added for each reservoir in the reservoir data file. This is because the program now tries to read an extra line of data for an off-channel reservoir. The model could have been set up to read this line only if a reservoir was an off-channel storage reservoir, but the data base manager for the input data base files would not support the format. Also, only ten of the fifty reservoirs allowed by the model can be off-channel storage reservoirs.
The model created when WIRSOS was modified is a very powerful tool for modelling water rights in the state of Wyoming. Furthermore, this tool should be capable of meeting the states needs into the future. As water becomes a more scarce commodity, each state needs the best tools possible to utilize their water to the best of their ability.
RECOMMENDATIONS
Two areas are possible candidates for future improvements to the WIRSOS model. These are 1) how area is calculated for the reservoir evaporation section of the model; and 2) equalization of water held in reservoirs.The area of a reservoir is currently calculated from the storage of the reservoir, and the area is calculated for the beginning and the end of each month. The two areas are then averaged to get an average area for the month for calculating evaporation. There are many ways in which this operation could be improved; however, most are too complicated for the simple nature of WIRSOS. Therefore, it was decided not to change this function at this time.
In the case of a project right being allowed to draw water from two reservoirs, the first reservoir must be empty before water is drawn from the second reservoir. In actual practice, water would be drawn evenly from both' reservoirs, and the program should reflect this actuality. However, such a change would require considerable restructuring of WIRSOS and its input files. Therefore, it was decided not to implement this function.
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