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<br />Comments on draft preliminary San Juan River Flow Recommendation <br />July 8, 1998 <br />Page 2 of5 <br /> <br />. <br /> <br />5.4.4 <br /> <br />Characterize the response of non-native fish species to varyingflow regimes <br />and recommendflows that minimize or eliminate interactions with native fish <br />species. <br /> <br />The Biology Committee has developed draft preliminary flow recommendations <br />along with proposed operating rules that relate operations of Navajo Dam to the draft <br />preliminary flow recommendations and an operating rule decision tree. The flow <br />recommendations are applicable to the mainstem of the San Juan River at the Shiprock <br />gaging station and on downstream. <br /> <br />Discussion <br /> <br />The draft preliminary flow recommendations were developed based on habitat as <br />defined by geomorphology and a statistical analysis of the historic hydrographs defining <br />how often flows occurred that provided the desired habitats and functions. The <br />recommendations subsequently are designed to maintain those same statistical parameters <br />in the long term. <br /> <br />Concerns <br /> <br />. <br /> <br />Based on our initial review of the draft preliminary flow recommendations, we <br />have a number of questions and concems. <br /> <br />. <br /> <br />I. How will the flow recommendations be implemented? Once flow recommendations <br />are adopted by the Coordination Committee, how will it be determined which <br />recommendations are to be given priority in a particular year? Will there be a public <br />process? The "Decision Tree" proposed for Navajo Reservoir offers a good start for <br />directing reservoir operations, but how is the "Decision Tree" integrated with the <br />actual flow recommendations? What opportunities exist for modification of the <br />"Decision Tree" should hydrologic conditions change dramatically? <br />2. How will the flow recommendations be used? It appears that a Section 7 Agreement <br />similar to that developed for the Upper Colorado River Basin Program is in order. <br />3. How will the flow recommendations be administered or enforced? While an <br />enforcement agreement is already in-place, attaching frequencies and conditions that <br />would require a certain condition to be met at least "once in every some many years" <br />is impossible to administer on a real time basis. <br />Colorado is concerned that frequencies can not be attached to the flow <br />recommendations in a meaningful manner on a real time basis. Frequencies can be <br />useful in deciding how you will operate Navajo Dam in any given year. Conditions <br />can be evaluated either by looking back in time or by projecting hydrologic <br />conditions forward in time. In either case, as a practical matter there has to be some <br />deference given to existing hydrologic conditions. From Colorado's perspective, the <br />flow recommendations should not include either frequencies or a "once in every some <br />may years" condition. Rather they should consider current hydrologic conditions and <br />seek to accomplish certain priorities under various hydrologic conditions. The <br />