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acre-feet/month) and the demand has b een assigned a link cost of -17500, wh ich is equivalent to a State <br />Engineer's Administration Number of approxima tely 14000.00000. This priority would be slightly <br />senior to the water rights for the Redlands Power Canal. <br />Instream Flow for the Black Canyon of the Gunnison <br />The second scenario assumes implementation of a re served right for enhancing the flows through the <br />Black Canyon of the Gunnison. For this demonstrati on, the demand is assumed to be at a year round <br />rate of 600 cfs (approximately 36,000 acre-feet/month) ; it is also assumed that the demand would be <br />assigned a relatively senior priority with a State Engineer?s Adminis tration Number of 30450.0000 <br />(model link cost of -14872). This pr iority would be senior to many of the major upstream water rights, <br />including the water rights of the Aspinall Unit reservoirs and Taylor Park Reservoir. <br />Assessment of the Impacts of a New Instream Flow Right <br />The impact to existing water rights resulting from a dding a new instream flow right is assessed by <br />comparing the results of a model run for a baseline condition on the river system with the results of a <br />model run that incorporates the ne w instream flow demand. A utility ( simdiv ) was developed to create <br />an output file ( modsim OUT file name.msd ) that lists every demand in the network, its node number and <br />the diversion to those demands for each time step of the baseline, and the instream flow model runs. A <br />UNIX script ( difmsd ) is then run that compares the tw o output files and generates a report ( difmsd.out ) <br />showing the differences between the two output f iles. The difference file lists each demand that <br />received a different volume of water between the two simulations. The file lists the demand, the <br />corresponding *.msd file, and the di version amount for each time step for the entire selected study <br />period for each model data set. For this task memorandum, the baseline simulation is represented by <br />the file strict2. data set, which is the strict administra tion network model as of February 2, 1995. For <br />the Redlands Power Canal scenario, the simulation is represented by the file redfish data set. The Black <br />Canyon scenario is represented by the file blc60 0 data set. <br />Examples of the full divers ion output files produced by simdiv and the difference file produced by <br />difmsd for the two scenarios are att ached to this memorandum. These files can readily be used to <br />evaluate which water rights would be impacted by th e imposition of a new inst ream flow right and to <br />what extent they would be impacted. Man-pages describing the utilities simdiv and difmsd are included <br />in the on-line documentation. <br />3.0 CONCLUSIONS/RECOMMENDATIONS <br />The prototype WRPM is designed to enable the user to readily evaluate th e impacts of alternative <br />scenarios of water rights development upon existing water rights and reservoirs. Using the MODSIM <br />interface, the user can interactively generate new demands, such as an instream flow requirement, by <br />creating a new demand node with an associated rate of flow and priority date. Utilities have been <br />developed to enable the user to easily evaluate the magnitude of any resulting impacts on other water <br />rights in the stream system network. <br />Examples are provided of two s cenarios in which new instream flow demands are imposed upon the <br />stream system, one involvi ng an instream flow requirement at th e Redlands Power Canal and the other <br />a senior reserved water right fo r the Black Canyon of the Gunnison. <br />2 <br />A275 02.23.94 1.15-29 Fosha, Ritsch <br />