WSP01897

• File Number: 8270.100
• Description: Colorado River Basin Water Quality/Salinity -- Misc Water Quality
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1977
• Author: USDOI
• Title: Quality of Water - Colorado River Basin - Progress Report No. 8 - January 1977
• Water Supply Pro - Doc Type: Report/Study

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EVALUATIONS OF EXISTI~G SALINITY CO~~ITIONS

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on Colorado River at Yuma. All-American Canal near Imperial Dam, Gila
Gravity Main Canal at Imperial Dam, Yuma Main Canal at Laguna Dam. and
~orth Gila Valley Canal at Laguna Dam less that of Gila River near Dome,
Arizona. Records after September 1960 are based on the combined daily
discharge of Colorado River passing Imperial Dam and at gaging stations
on All-American Canal near Imperial Dam and Gila Gravity ~ain Canal at
Imperial Dam and the division to Mittre Lake.

Quality data from 1943 through October 1970 were obtained from
Geological Survey records and are based on data for the Yuma Main Canal
below the Colorado River Siphon. The water quality data for ~ovember
and December 1970 and for calendar years 1971-1974 were obtained from
the Geological Survey records for the water quality station at Imperial
Dam. The samples are presently being collected by the Geological
Survey and the Bureau of Reclamation above the trash racks at the di-
version to the All-American Canal. Salinity analyses are made by the
Geological Survey in cooperation with the Bureau of Reclamation. Field
analyses and bacteria determinations are made by the Geological Survey
in cooperation vith Environmental Protection Agency.

3. Other Qualitv of Water Stations

4It In addition to the key stations discussed above, there are many
more points at which water quality data are obtained. Most of these
sampling stations are operated by the Geological Survey; however, a number
are operated by the Bureau of Reclamation and other Federal, State, and
private agencies.

The type of data obtained and the purpose of the sampling vary with
each station. Many of the stations provide data for the Water Quality
Improvement Program in Part VIII and special studies described in Part X.

B. Methods of Chemical Analyses

Published quality of water records consist of a combination of
stream discharges with chemical analyses of stream water samples collected
at more or less regular intervals. The reliability of the records
depend on the accuracy of the streamflow records, the frequency of
collection and representativeness of the samples, the stability of the
samples during the storage periods prior to making of the analyses, and
the completeness and accuracy of the individual analyses.

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Most of the chemical analyses of water samples which provided the
water quality data were made in the laboratories of the Geological
Survey at Washington, D.C., Albuquerque, ~ew Mexico, and Salt Lake City,
Utah, using standard procedures by chemists specifically trained in
water analysis. During the 34-year period considered there were several
changes in laboratory techinques and procedures mostly due to introduction

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