Water-Quality Data for Selected National Park Units, Southern and Central Arizona and West-Central New Mexico, Water Years 2003 and 2004

Brown, James

In 1992 the National Park Service began a Level 1 Water Quality Data Inventory program to make available to park managers the water-resource information with which to best manage each park and plan for the future. Scientists at the U.S. Geological Survey Arizona Water Science Center in Tucson, Arizona, collected water samples and other water-quality information at 30 sites in 9 park units in southern and central Arizona and west-central New Mexico in water years 2003 and 2004. Sites consisted of springs, seeps, mine adits, streams, and wells. The baseline water-quality data presented in this report were determined through field measurements and laboratory analyses of selected physical properties and chemical constituents. Field measurements made at each site were pH, specific conductance, water temperature, dissolved-oxygen concentration, and alkalinity. Water samples collected at each site were submitted to the U.S. Geological Survey National Water Quality Laboratory and analyzed for major-ion, trace-element, and nutrient concentrations. Analyses done at selected sites included turbidity, coliform counts, and concentrations of suspended sediment, turbidity, cyanide, and arsenic. Quality control for this study was maintained through the use of proper training, use of standard field and laboratory protocols, collection of sample blanks and replicates, and thorough review of the analytical results. Laboratory analyses were done using methods approved by the U.S. Geological Survey or the U.S. Environmental Protection Agency. Measured field pH values ranged from 6.4 to 9.2, within the normal range expected for springs and rivers. Dissolved-solids concentrations ranged from 49 to 1,570 milligrams per liter; most values were less than 700 milligrams per liter. Dissolved-solids concentrations of less than 100 milligrams per liter were almost always associated with springs at altitudes higher than 7,000 feet in the Rincon Mountain District of Saguaro National Park. Trace-metal concentrations at most sites were at or near laboratory reporting levels. The highest metals concentrations were at Blue Waterfall Seep below an unnamed mine in Coronado National Memorial where concentrations of dissolved copper were as high as 505 micrograms per liter. Concentrations of dissolved zinc at were as high as 3,650 micrograms per liter at Blue Waterfall Seep below an unnamed mine and 1,530 micrograms per liter at Barrel Springs windmill. Concentrations of dissolved arsenic were measured in water samples from the Middle and West Forks of the Gila River in the Gila Cliff Dwellings National Monument and ranged from 0.5 to 1.6 micrograms per liter. Not including sites in Coronado National Memorial, most concentrations of dissolved uranium were less than 10 micrograms per liter. At one site in Coronado National Memorial concentrations were as high as 122 micrograms per liter. Fecal coliform bacteria colony counts were made at 12 sites to indicate the possible presence of contamination from human or animal wastes. Samples were collected twice at nine sites and once and three sites. Colony counts ranged from 0 colonies per 100 milliliters at two sites to 660 colonies per 100 milliliters at Beaver Creek in Montezuma Castle National Monument. At sites where more than one analysis was done, colony counts varied significantly from visit to visit.

Water-Quality Data for Selected National Park Units, Southern and Central Arizona and West-Central New Mexico, Water Years 2003 and 2004

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