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<br />:-:> <br />:~ <br />" <br />.~ <br /> <br />DRAFT San Juan Flow Recommendation Comments <br />May 8, t998 <br />Page> of 5 <br /> <br />- <br />',' <br /> <br />otherwise allowed to go forward? Once a project is approved, there is no way of <br />assuring that any specified flow amounts will remain in the river in any given year <br />since the flows are provided for on a statistical basis that must be determined over a <br />period of years, What is the period of years that will be used to determine wbether or <br />not a project or projects have violated the flow recommendations? <br />5, How is the Service going to evaluate whether or not a new project significantly <br />affects the statistics incorporated into the flow recorrullendations? Will it run the <br />existing model with the proposed project inserted? If so, whose responsibility will it <br />be to make sure that the model is up to date? Given tbat the Riverware model is <br />proprietary and requires a license to use it, someone will need to be tasked with <br />keeping the configuration and databases current. <br />6, Operations ofNav~o Dam must be consistent with the authorizing legislation and <br />state water rights, It is not clear whether or not authorities and water rights for <br />Navajo Dam include storage releases for downstream fisheries and we are of the <br />opinion this issue is not being addressed, There is a distinction between bypasses and <br />storage releases. <br />7. The proposed operating rules for Navajo Dam provide for a determination of <br />available water. However, the proposed rules do not describe how that determination <br />is made. The runoff period should be defined. Suggest April 15 to July IS. Over <br />what period is the determination of available water for, April-July, annual or other? <br />How are existing uses factored into the determination? Is Reclamation's <br />"RiverWare" model the definitive tool for determining water availability? What risks <br />are allowable to the safe yield of Navajo Reservoir? <br />8, How do you justify attaching a frequency to the J 0,000 cfs peak flow of once every <br />10-years when such a condition even with minimal new development will not be <br />available for a IS-year period between 1958 and 1973 based on the current modeling. <br />9, What is the justification for the peak flow pattern suggested? What is the baseflow <br />from which we begin to ramp up? It appears to be 500 cfs out of Navajo Reservoir. It <br />appears that the ramp up rates and ramp down rates where considered to be constant <br />in the evaluations during any given year based on the volume of water available. In <br />other words, the rate at which ramping up or down occurs will vary from year to year <br />but not within the year, What is the basis for this? On other rivers the ramp up and <br />down rates have become fairly well defined based on species and habitat concerns, <br />why shouldn't it be a constant predefined pattern or patterns based on the research. It <br />seems to us that there should be some more specificity given to ramping rates and <br />patterns since the trout fishery below Navajo is likely to be most affected and inflows <br />from the Animas will provide a lot a variability anyway, <br />10. How are the flow recommendations justified when lower flows at 4-Comers appear to <br />indicate better and more habitat? <br />11, The operating rules state that the minimum baseflow is to be 500 cfs at the <br />Farmington, Shiprock, Four Comers and Bluff gages (the average minimum to be <br />determined by taking an average of the flows at any two gages), with a minimum <br />release from Navajo of250 cfs. Are you considering a mean daily average allowing <br />for lag times, or only the instantaneous flow at any gage at any time? <br />12. It needs to be clearly stated that satisfaction of the peak flow will be determined <br />based on the gaged flows at Shiprock. If the peaks at Four Corners and Bluff Me also <br /> <br />:, ;..:"..., <br /> <br />o <br />