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<br />001761 <br /> <br />Copper diss (uglL) 1.2 <br />Lead diss (uglL) <1.0 <br />Manganese diss 8 <br />(uglL) <br />Nickel diss (uglL) ND <br />Silver diss (uglL) ND <br />Zinc diss (uglL) 2,6 <br />Aluminum diss (uglL) <10 <br />Selenium diss (uglL) ND <br />Selenium total (uglL) ND <br />Hardness (mglL) 184 <br />Nitrate diss N03 0.3 1.6 (n=3) 3,1/0.4 <br />(mg/L) <br />Mercury diss (uglL) ND <br />Iron diss (uglL) ND 15 (n=7) 60 (n=5) 210/10 <br /> <br />Notes: For data that was below detection levels, the value used to calculate the average value was Y2 the detection <br />limit. ND is not detected as reported by the laboratory doing the analysis. n is the number of samples analyzed, <br />diss is dissolved. Historical data taken from EPA STORET retrieval for this sample site. Data for 250 cfs flow from <br />after construction of Navajo Dam in 1960's and 1970's, mostly late summer, but also several May and June sample <br />dates. Majority of data for 500 cfs period dated during or after construction of Navajo Dam, Most data from 1970's. <br /> <br />As Table E illustrates, very little data (blank cells) has been collected at the sample site <br />historically. It also illustrates that temperature, conductivity, and bicarbonate ion continue to be <br />above the 500 cfs average, but within the historical range of data. <br /> <br />Both tables (D and E) confirm analysis that show TDS and associated ions are expected to <br />increase with a decrease in flow and metal trace elements show no correlation to flow. The same <br />relationship was found by the San Juan River Basin Recovery Implementation Program in their <br />water quality analysis of the San Juan River. <br /> <br />The standards for water uses like irrigation, livestock, and wildlife habitat would most likely not <br />be exceeded during long term low flows. Data from the low flow test shows parameters well <br />below the standards, <br /> <br />The warmwater fishery standards (water temperature, dissolved oxygen, pH, and total ammonia) <br />would most likely not be exceeded based on the data from the low flow test sampling. The total <br />ammonia parameter is closest to the standard and additional monitoring may be necessary during <br />low flows periods, <br /> <br />The water temperature standard (25oe) for marginal coldwater fishery within segment 20.6.4.401 <br />would be exceeded during the summer. The parameter would probably have to be added to the <br /> <br />Page 13 of 15 <br />