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<br />Memo to Colorado Water Conservation Board Members <br />From: Peter Evans and Gene Jencsok <br />Date: October 17, 1995 <br />SUBJECT: Agenda Item 2, October 20, 1995 Board Meeting <br />Endangered Fish Recovery ISF Water Right - Colorado River (Mainstem) <br /> <br />Page 8 <br /> <br />endangered fish. The total instteam flow appropriations suggested in Table 4 are no greater on average than will flow out of state under the <br />compacts. The more significant challenge witt be in arriving at monthly or daily distributions for these annual amounts which protect both <br />water development opportunities and the needs of the endangered fish given the variable hydrology which occurs both annually and seasonally. <br />Also, the structure and fannat of the water right application will be important. particularly in tight of the recent decision in the Aspen <br />Wilderness Workshop. Inc. v. The Colorado Water Conservation Board (Snowmass Creek Case). <br />"H. Our recommended approach does not foreclose any reasonable development opportunities within Colorado's compact <br />apportionment As suggested in the ewes's Statement of Policy and Procedure, it presumes that within the time it will take to fully develop <br />the recommended range of new consumptive uses, new infonnation about the endangered fiSh will become available such that the CWCB and <br />others will find it necessary to reevaluate the situation and the state's needs. The open process employed in assembling these <br />recommendations, facilitated through the support of the CWCB's staffand others, is helpful in promoting the use of the best information <br />available and enabling a diverse group of interested parties to participate in policy formulation. However, there are limits to what can be <br />expected from a group representing statewide interests, and the organization of similar groups within the principal subbasins should also be <br />pursued in order to fine tune the infonnation." <br />We have reviewed these observations and recommendations, and have taken them into <br /> <br />consideration in the development of our recommendation. <br /> <br />Physical Water Availability Studv. Before the CWCB can appropriate an instrearn flow <br />water right, it must determine that water is physically available for the appropriation within the <br />proposed instream flow segment. Water availability studies for the 15 Mile Reach have been <br />conducted using hydrologic and water rights administration records from the Cameo Gage, <br />which is located upstream of the proposed instrearn flow segment. Streamflow records for the <br />1970-1992 period were evaluated and adjusted to reflect current (1992) levels of depletion. <br />Daily and average monthly flows were analyzed statistically, and daily and monthly flow <br />duration curves were plotted, In addition, annual volumes and annual peak flows were tabulated, <br />statistical distributions were calculated, and flow duration curves for the annual volumes and <br />annual peak flows were plotted. <br />These curves can be used to determine what percentage of the time a given daily flow, <br />monthly flow, annual volume, or annual peak flow would occur during the adjusted 1970-1992 <br />period in the 15 Mile Reach. This information is documented in a report entitled Colorado River <br />_ 15 Mife Reach, Physical Water Availability Study and dated August 30, 1995, <br /> <br />Other Efforts to Restore and Protect Flows in the IS Mile Reach. It has become obvious <br />that restoration and protection of flows which "mimic" the natural flow regime for the IS Mile <br />Reach cannot be accomplished through the appropriation of junior water rights, Management of <br />water resources upstream from the 15 Mile Reach for consumptive and non-consumptive uses <br />have substantially altered the natural flow regime. Furthermore; there are many conditional <br />water rights (approximately 3.6 million acre-feet of storage rights and 90,500 cfs of direct flow <br />rights) which will be senior to the proposed 1995 fish recovery instream flow water rights. If <br />developed, these senior rights would take priority in the allocation of available water and could <br />significantly reduce the existing flows in the 15 Mile Reach. <br />Therefore, the Recovery Program has initiated several supplemental efforts to improve <br />flow conditions in the 15 Mile Reach. These supplemental efforts include agreements for the' <br /> <br />95C 1496 <br />