Surface-water-quality data for Oklahoma have been published by the U.S. Geological Survey in cooperation with various State agencies on an annual basis since 1949. The published data represents 2,733 station-years of data from 527 stations, ranging from one sample from a station once during the thirty--year period to a continuously operating daily station were more than one hundred samples were collected in a year. The last comprehensive index was published in 1963; since that time various unpublished indexes have been in use, none of which were complete.
Most of the water-quality data collected and published prior to 1970 was for the common inorganic constituents such as, calcium, magnesium, sodium, alkalinity, chloride and sulfate. Since 1970 other types of data such as the minor or trace metals, organic compounds including pesticides, nutrients, oxygen resources, and biologic information have been collected and published with ever increasing frequency.
This index was designed to provide the data user a means of rapid search for stations by downstream order (Table 2), county (Table 4), and alphabetically by stream or station name (Table 1). Table 1 also provides a breakdown of the data into 10 broad water-quality categories.