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<br />.' <br /> <br />. <br /> <br />Page 5 <br /> <br />Task 7 - Develop basin network and hydrology files <br /> <br />In this task, Boyle will execute the makenet and tstools DMls to create new river <br />system files for the Yampa model. These include the river network ('.net) file, the <br />historical streamflow file ('.rih) file, river station ('.ris) file, and base streamflow ('.rib) <br />file. The task involves these steps: <br /> <br />1. Review availability of gage information and determine which gages should be <br />included in the model. <br /> <br />2. Develop a new '.net file that includes Battle Creek, Muddy Creek, and the North, <br />Middle and South Forks of the Little Snake River. The new network file will <br />contain nodes for the Pothook Reservoir site on Savery Creek, High Savery Dam <br />on Savery Creek, and up to three additional reservoir sites that CWCB identifies. <br />The Green River Basin Plan will be reviewed to determine which diversion <br />structures should be included. At a minimum, the Cheyenne diversions, Town of <br />Baggs, and five irrigation structures that were included in the diversion memo <br />task for the Green River Basin Plan will be added to the model. Other diversions <br />may be left in the gage or represented in aggregations, and this task will <br />determine what approach will be taken based on amount of use represented by <br />small structures, and availability of information on permits, actual irrigated acres, <br />and return flow locations. <br /> <br />Boyle will develop area and precipitation factors for baseflow inflow points that <br />will be subject to change depending on calibration results. The factors will be <br />based on USGS mapping and average annual isohyetal mapping if CWCB can <br />provide it as a GIS coverage. Alternatively, factors can be developed based on <br />drainage area alone and/or runoff ratios between gages that are included in the <br />model and short-term gages that have not been included in the model. <br /> <br />3. Boyle will execute makenet to create new Yampa basin model input files. <br /> <br />4. Boyle will assemble an '.rih file based on gage data collected and filled during <br />the Green River basin plan. <br /> <br />5. Boyle will review the information available from the Green River Basin Plan <br />related to consumptive use, diversions, permitted acreage, and actual irrigated <br />acreage under specific diversion structures. Irrigation efficiencies for two <br />structures, First Mesa and West Side Canals, were determined under the Plan <br />for Average, Wet, and Dry years. These may be used to develop diversion <br />demands at other structures; alternatively, consumptive use may be used as a <br />diversion demand. An approach to modeling irrigation demand will be <br />determined. <br /> <br />Deliverables: <br />. Model input files, and DMI files that created them <br /> <br />Exhibits_new <br /> <br />3/5/2003 <br />