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<br />TYPES OF WATER.QUALlTY DATA
<br />
<br />The types of water -quality data mea~ured and
<br />analyzed at each surface-water station are listed in
<br />table I. The surface-water stations are presentcd in
<br />downstream order. Special samples at some stations
<br />indicatc the irregular collection and analysis of addi-
<br />tional water-quality constituents that were appended
<br />to routine samples normally collected during station
<br />visits. Continuous water-quality and discharge data
<br />have been collected at some of the stations, but are not
<br />published in this report. Howcver, these data are pub-
<br />lished in the annual Colorado Water-Data Report series
<br />and are available upon request. The types of water-
<br />quality data presented in this report are:
<br />
<br />I. Onsite measurements, including instantaneous
<br />discharge and field detemtination of specific
<br />conductance. pH, water temperature, and
<br />dissolved-oxygen concentration. .
<br />
<br />2. Bacteriological field analyses, including total
<br />coliform, fecal coliform, and fecal strepto-
<br />cocci.
<br />
<br />3. Dissolved solid~, including alkalinity, dissolved
<br />calcium, dissolved magnesium, dissolved
<br />sodium, dissolved sulfate, dissolved chloride,
<br />and dissolved-solids residue at 180oC.
<br />
<br />4. Major nutrients, including total nitrite plus nitrate
<br />a~ nitrogen and total arnmonia as nitrogen for
<br />1990 through 1992; dissolved nitrite plus
<br />nitrate as nitrogen and dissolved ammonia as
<br />nitrogen for 1993; and total phosphorus for
<br />1990 through 1993.
<br />
<br />5. Trace elements, including total and dissolved
<br />arsenic, cadmium, chromium, copper. iron,
<br />lead, manganese, mercury, nickel, selenium,
<br />silver, and zinc.
<br />
<br />6. Pcsticides, including organochlorine and organo-
<br />phosphorus insecticides and thc chlorinated
<br />phenoxy-acid herbicides.
<br />
<br />7. Radiochemical constituents, including total and
<br />dissolved gross alpha and gross beta constitu-
<br />ents and dissolved natural uranium.
<br />
<br />8. Suspended sediment, including suspended-
<br />sediment concentration and thc percentage
<br />of the suspended scdiment fincr than sand
<br />(less than 0.062 rnm).
<br />
<br />Methods of Data Collection and Analysis
<br />
<br />Before each field trip, a standard cleaning and
<br />rinsing procedure wa~ used to prepare the equipment
<br />for water-quality sampling. Sampling equipment was
<br />completely disassembled and washed thoroughly using
<br />a solution of nonphosphate laboratory detergent, fol-
<br />lowed by three thorough rinses using public-supplied
<br />tap water. Sampling equipment then was rinsed using
<br />a I-percent hydrochloric acid solution and triple-rinsed
<br />using deionized water.
<br />Upon arriving at each surface-water station,
<br />prior to a sample collection, the sampling equipmcnt
<br />was rinsed once with deionized water, followed by
<br />a rinse with dilute hydrochloric acid, followed by a
<br />triple-rinse with deionized water. Finally, the sampling
<br />equipment was triple-rinsed thoroughly with native
<br />streamwater before the collection ofa watcr-quality
<br />sample. At all stations sampled downstream from the
<br />Arkansas River near Avondale, station 07\ 09500
<br />(table I), east of Pueblo to the Colorado-Kansa~ State
<br />line (pI. I), the dilute hydrochloric acid rinse was omit-
<br />ted because trace-level contamination ofsanlples was
<br />not a concern in sampling the lower basin.
<br />Onsite mea~urements were made during each
<br />site visit at surface-water stations using standardized
<br />procedures and techniques (U.S. Geological Survey,
<br />1977). Stream discharge continuously was monitored
<br />at some stations or a discharge measurement was made
<br />at the time of sampling at other stations. Field water-
<br />quality analyses were made for specific conductance,
<br />pH, watertemperature, and dissolved oxygen (Fishman
<br />and Friedman, 1989). Water samples for bacteriologi-
<br />cal analyses were collected onsite at 17 surface-
<br />water stations (table I) with clean sterilized glass
<br />bottles using a multivertical sampling procedure
<br />(Patrick Edelmann, U.S. Geological Survey, oral
<br />common., 1990). Bacteriological samples were filtered
<br />and analyzed in the field using methods described in
<br />Britton and Greeson (1987).
<br />Water samples for chemical analyses were col-
<br />lected using standardized U.S. Geological Survey
<br />guidelines (Sylvester and others, 1990). Except for
<br />extreme flow situations, surface-water samples from
<br />the stream were depth-integrated using the equal-
<br />width-increment method (Sylvester and others, 1990)
<br />and were transferred into a chum splitter for a compos-
<br />ite sample. The churn splitter allowed different sub-
<br />sample volumes to be obtained from the sample while
<br />still maintaining the ba~ic chemical and physical
<br />properties of the original samplc. Numerous aliquots
<br />were taken from the churn splitter. processed, and
<br />preserved onsite using methods described in Ward
<br />and Harr(l990). Water-quality samples were shipped
<br />on a regular basis to the laboratory for analysis of the
<br />chemical constituents.
<br />
<br />4 Water-Quality Data for the Arkansa.!1 River Basin, Southeastern Colorado, 1990-83
<br />
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