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000700 Steve Schmitzer's Comments Fork exchange was not being modeled correctly by StateMod. In order to more closely match P ACSIM results we split the Williams Fork exchange into two rights, a senior right for winter (Jan-March) and a junior right for summer (April-Dec), For some years in which run-off occurred in March, Williams Fork was operating with a senior exchange right. The important point is that this is not a fatal flaw for CFOPS. In comparison to P ACSIM, the yearly results are more accurate than for the individual months. Likewise, with the 110,000 af of future demands (50,000 af of which is increased demand on Dillon Reservoir), the substitution requirements of Denver's pool in Wolford will be greater, and the contents of Wolford Mountain Reservoir (Figure 36) should be much lower in 1977, not higher as shown in STATEMOD. Same story as WRF, Green Mountain does not fill in dry years with increased demand and so exchange can not take place. Other limitations include the modeled period of 1975-1991, which doesn't include the mid- 1950's critical drought periodo This time period was agreed to at the start of the study. The lack of daily routing of reservoir releases also minimizes the real-time problem of dealing with lag times and overestimates the efficiency of making the correct amount of reservoir release at the right timeo Monthly model, StateMod was chosen and agreed to by everyone at beginning of study. The modeling includes the operation of 5,412 af fish pool in Williams Fork (po 20). This is a temporary arrangement which should not have been assumed in the Baseline hydrology. We used Cl dataset as it was given to us by the State. Page 30 states that because the 20,000 af does not have to be supplied in dry years, the effects on reservoir firm yield are minimized or eliminated. While this is true for individual dry years, it is important to note in the report that reservoir operators usually don't know when a drought has beguno If water is released from a reservoir in an average year preceding a drought, and the reservoir doesn't subsequently fill, then firm yield has been lost. Another concern is a year such as 1978 that follows the severe dry year of 1977. In 1978, the 20,000 affor flows in the IS-Mile Reach are required even though reservoirs such as Williams Fork have not refilled. Until the reservoirs completely refill, the reservoir operators have no way of knowing when the critical drought period is over. The report incorrectly assumes that water would be released in a year such as 1978. It was not in the scope of work to define the operating rules for CFOPS, nor predict future flows. The study focuses on what was feasible historicallyo USFWS will have to ultimately define the operating/participation rules and hopefully include drought provisions to avoid the above described scenario, It needs to be decided if CFOPS will be mandatory or voluntary. II The goal of an additional 20,000 af is an average volume to enhance spring peak flows in the 15- Mile Reach. In some years more water is available, and in other years less is available. If the junior Green Mountain Reservoir refill right is aggressively used for CFOPS, it could preclude Douglas County from getting much water under a new junior water right at Dillon Reservoir. Being able to derive new yield from a junior water right at Dillon Reservoir is critical for success of a cooperative arrangement among Douglas County, the River District, and Denver Watero Success on this cooperative effort is important to harmony between the east and the west. It was P:\Data\GEN\CWCB\19665\Report Phase 2\Technical Memorandum No" 12\Appendix B"doc 8