Questa baseline and pre-mining ground-water quality investigation. 3. Historical ground-water quality for the Red River Valley, New Mexico

Historical ground-water quality data for 100 wells in the Red River Valley between the
U.S. Geological Survey streamflow-gaging station (08265000), near Questa, and Placer Creek
east of the town of Red River, New Mexico, were compiled and reviewed. The tabulation
included 608 water-quality records from 23 sources entered into an electronic database. Groundwater
quality data were first collected at the Red River wastewater-treatment facility in 1982.
Most analyses, however, were obtained between 1994 and 2002, even though the first wells were
developed in 1962.
The data were evaluated by considering (a) temporal consistency, (b) quality of sampling
methods, (c) charge imbalance, and (d) replicate analyses. Analyses that qualified on the basis
of these criteria were modeled to obtain saturation indices for gypsum, calcite, fluorite, gibbsite,
manganite, and rhodocrosite. Plots created from the data illustrate that water chemistry in the
Red River Valley is predominantly controlled by calcite dissolution, congruent gypsum
dissolution, and pyrite oxidation.