From the Proceedings of the 1976 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 29-May 1, 1976, Tucson, Arizona / To provide quantitative baseline information on water quality of streamflow from ponderosa pine watersheds on sedimentary soils, water samples were collected at the mouths of four watersheds at time of surface runoff and during extreme or unusual hydrological events. In each sample, calcium (Ca++), magnesium (Mg++) and sodium (Na+) were determined by using atomic absorption spectrophotometry; carbonate (CO=3) and bicarbonate (HCO-3) were measured by titrating with standard acid; fluoride (F-), sulfate (SO=4), 3 nitrate (NO-3), and chloride (Cl-) were determined by colorimetric methods using an Autoanalyzer; hydrogen ion concentration (pH) was measured by using a glass electrode; and suspended sediment concentrations were determined by filtration. The data obtained were compared with EPA water quality standards for aquatic life, irrigation, and public water supply. Although the EPA levels of acceptability have not been established for many of the chemical and physical water constituents, the parameters determined in this study, in general, fall within the EPA prescribed limits.