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Volume III - Comments and Responses FENS - Navajo Reservoir Operations suggested that contaminants would not limit the recovery of the two endangered fish species." Studies continue on the San Juan River to monitor water quality conditions and their relationship to the health of the endangered fish. - Reduced releases from Navajo Reservoir will not "add" pollution, but will cause an increase in the concentration of some water quality parameters due to the reduction of good quality water released from the reservoir. The area of most concern, identified in San Juan River low flow tests, is the reach of river between Navajo Dam and Farmington. As seen in the low flow tests, this reach had changing concentrations of several parameters, like temperature, dissolved oxygen, and salinity, which are directly related to changes in flow. Several other parameters also exceeded New Mexico's water quality standards, but the majority of parameters remained within the standards. Historic data indicate some - parameters occasionally exceeded State standards in this reach. The reach of the San Juan River below Farmington-the reach occupied by the endangered • fish-should not experience a decrease in minimum flows, but an increase in base - (minimum) flows through most of the year due to the requirement for a base flow between 500 and 1,000 cfs for the endangered fish. Based on historic water quality data, these flows will keep most water quality parameters above the States' and Tribes' water quality - standards. Historic data indicate some water quality standards have been exceeded in the - past, and this trend will likely occur in the future, but it is not anticipated to be significantly greater than the historic records. - For additional water quality issue responses, see General Comment No. 23. General Comment 21: Several comments were received on the validity of the baseline (existing depletion estimations) used in the DEIS analysis. - (a) The RiverWare Hydrology Model contains a number of errors. The RiverWare model is currently under review by the SJRBRIP and others; Reclamation should respond to model improvements through adaptive management, etc. - Response: RiverWare was the simulation model selected for use in this analysis. It has been implemented in the Basin since 1998 in support of assessing the relationship between flow recommendations for endangered fish in the San Juan River and water development. - The model, in its present configuration, represents the best science available to assess the - impacts of water development on the ability to meet Flow Recommendations for the endangered fish and to test operating rules designed for that purpose. The presently defined operating rules and model configuration do not indicate availability for substantial - additional depletions in the Basin with the present Flow Recommendations. Future water - development is addressed in chapter II, "VII. Preferred Alternative," of the FEIS.