WSP09250

• File Number: 8278.400
• Description: Title I - Mexican Treaty and Minute 242
• Basin: Colorado Mainstem
• Date: 1/1/1970
• Author: IBWC
• Title: Minute 242 Annual Report
• Water Supply Pro - Doc Type: Annual Report

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3. Salinity of Colorado River Waters Delivered to Mexico from Imperial Dam

Colorado River waters above Imperial Dam delivered to Mexico had an average
annual salinity of about 852 ppm in the 5th year of operation, an increase of
22 ppm over that in the previous year. The average annual salinities of waters
from above Imperial Dam delivered to Mexico in 1965 and for the past five years
of operations under Minute No. 218 are tabulated bel.ow:

SALINITY OF COLORADO RIVER WATERS DELIVERED
TO MEXICO FROM IMPERIAL DAM

Operation
Vear

Average Sol inity
ppm

Previous year to
Agreement Operations

1965

910

1966
1967
1968
1969
1970

894
799
809
830
852

4. Solinity of Return Flows to Colorado River Below Imperial Dam

The return waters below Imperial Dam, including those at San Luis, had an average
salinity of 2120 ppm during the 5th year, excluding all return flows to the river
below Morelos Dam by means of the by-pass channel. The principal sources of
returns are as follows:

a) The Well ton-Mohawk Drainage Waters. The largest source of
return flows below Imperial Dam comprise the drainage waters
from the Wellton-Mohawk Project. These, in the 5th year of
operation, amounted to 219,300 acre-feet, slightly more than
in 1969. Total salts discharged are estimated to amount to
1,129,000 tons, a reduction from the 4th year of about 98,000
tons due to the decrease in salinity of the pumped waters. The
average sol ini ty of the Well ton-Mohawk drainage waters in the
5th year in the conveyance channel above Morelos Dam averaged
about 3790 ppm, a reduction of about 340 ppm from that in 1969.
Comparative data are tabulated on the foil owing page, and shown
graphically in Exhibit 5.