Laserfiche WebLink
<br />'i (1:~.., <br />.Uu{ <br />.. <br /> <br />WATER QUALITY <br /> <br />During the 1980 Calendar Year, the average flow-weighted <br />salinity of the waters delivered to Mexico above Morelos Dam was <br />740 ppm and the salinity of the Colorado River waters which arrived <br />at Imperial Dam was 755 ppm. Thus, the differential between the <br />average salinities at Morelos Dam and Imperial Dam was -15 ppm. <br />This value not only falls within the requirement of Minute No. 242 <br />of the International Boundary and Water Commission that the differen- <br />tial be no greather than 115 + 30 ppm, it is also the second year <br />since Minute No. 242 commencea that salinity at Morel os. Dam has been <br />lower than at Imperial Dam. This unusual situation occurred because <br />of the large quantities of Gila River flood waters of low salinity <br />that entered the Colorado River below Imperial Dam and above Morelos <br />Dam. <br /> <br />During the same period, all of the drainage return flows from <br />the Wellton-Mohawk Irrigation and Drainage District, 154,600 acre- <br />feet, were bypassed via the Wellton-Mohawk bypass drain. Of this <br />amount, 21,400 acre-feet were replaced by ground water from the <br />Yuma Mesa well field and the balance, 133,200 acre-feet, would have <br />had to be released from storage, except that the releases from the <br />Lower Basin flood control dams and the anticipatory floqd releases <br />from Lake Mead provided more than enough water to replace the by- <br />passed quantities. <br /> <br />Table 11 summarizes operations under Minutes Nos. 218, 241, <br />and 242 for the period 1971 through 1980. <br /> <br />-12- <br />