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. .' . calculated based on water use and assuming full project development; however, since the Dolores Project is not yet fully developed, the total calculated return flow to the San Juan River has not been realized. Also, total water demand from the Project is not what was originally projected. For example, the City of Cortez has not used their full allocation of Project water and has indicated it would not need their full allotment in the future. As described above under alternatives 1,2 &3, Reclamation would acquire additional water rights allowing for this water to remain in the Dolores River basin. Since the water that would be acquired has not yet been provided to whom it had been allocated, once acquired, there would be no actual loss of flow to the San Juan River. The acquisition of this water by Reclamation would reduce the amount of return flow that might enter the San Juan River if it were to' be diverted to the San Juan River basin. The effect, if any, would occur to amount of potential return flow that could one day enter the San Juan River. Described below is the estimated effect the proposed action could have on flow in the San Juan River and federally protected fish species inhabiting it. Simply changing to pool management in lieu of providing three varying base flows (USBR, 1977), described above under the No Action Alternative, would not affect the long-term average annual volume of water released into the San Juan River_ However, the acquisition of additional water to increase the managed pool volume would decrease the projected volume of water entering the San Juan River. The water entering the San Juan River, mostly from irrigation return flow, would occur at the confluence of McElmo Creek near Aneth, Utah. Currently, Reclamation is negotiating with several entities for the acquisition of additional water to increase the yearly volume of water available to benefit fish and wildlife resources downstream of McPhee Dam. Since Reclamation has not firmly identified the "type of waterll it would acquire, it is difficult to specifically address how much water would be depleted from the San Juan River. For example, for M&I water, a 50% consumptive rate is assumed; with irrigation water it's estimated water is consumed at a 80% rate. Therefore, depending on the source of. additional water acquired for the Dolores River fish and wildlife pool, the associated effect on return. flow to the San Juan River could vary. Currently, the water that would be acquired is not being used from the project; therefore, acquiring this water would not have an actual direct effect. During Formal Consultation with the Service as required under the Act, this water was assumed to eventually reach the San Juan River and is included in the San Juan River baseline. Since the closure of McPhee Darn, this undeveloped project water has been released downstream during spills from McPhee Darn. SPECIES ASSESSMENT The Colorado squawfish and the razorback sucker are known to exist in portions of the San Juan River downstream of where Dolores Project irrigation return flows enter the river (Platania, 1990). The majority of these return flows enter the San Juan River at the McElmo Creek confluence. In addition; a relatively large population of flannelmouth suckers (Platania, 1990) and possibly a small population of roundtail chubs also exist in the San Juan River downstream of McElmo Creek (pers. comrn. Tom Beck, CDOW, 1988). It is possible that all of these species may attempt spawning in this section of the San Juan River. While sexually ripe razorback suckers' have been collected from the San Juan River and the San Juan arm of Lake Powell in recent years, no young-of-the-year or juvenile razorbacks have been sampled from the system; therefore, recruitment by this species may not be occurring (Platania, 1990). IS