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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />, <br /> <br />date of February 10 when Well ton-Mohawk drainage appeared, The second and <br />higher one is 1613 ppm which is the average of the 81 readings representing 174 <br />days taken from June 1 to December 31. It seems that it took 258 days from <br />" <br />February 10 to October 25, before someone .started taking even a~electric <br />conductivity test daily. Hence, the 1961. number of 1613 ppm may be questionable <br />but it is the best information available, You will note that the highest annual <br />average is 1739 ppm in 1962 and according to Mexican figures it was only 1493 ppm. <br />Your attention is called to the highest daily reading of each year and <br />we have three readings of more than 3000 ppm, the maximum being 3100 in 1964. <br />And I will show you on Figure 14 that salinities greater than 3000 occurred only <br />on 10 days during the 1961-71 period unless some of them fell during the period <br />February 10 to June I, 1961 and, judging from Table l3b, that is not likely. <br />There is another interesting feature on this graph. That is the salinity <br />of the effluent on the downstream or Mexico side of the Boundary Pumping Plant, <br />The East Main Canal (Figure 15), with a spill of about 4,000 acre feet per year, <br />and the Yuma .Valley Main Drain (Figure 16, a pumping plant), about 130,000 acre <br />feet per year, empty into the San Luis Valley. This salinity here averages <br />approximately 1700 ppm, (again by use of my factor of 0,674), yet Mexico is <br />apparently happy to have it, she pays $B,OOO per year for it and has for a long <br />time. It is used as is for the cultivated area immediately adjacent to the city <br />of San Luis but is mixed with river water when it reaches the canal coming from <br />the San Luis siphon. <br />It would be interesting to know if it were mixed with river water during <br /> <br /> <br />the period between February 10, 1961 (arrival of Well ton-Mohawk drainage) and <br /> <br /> <br />June 28, 1963 (first use of the siphon under the Colorado at San Luis). I assume <br /> <br /> <br />that it was and that the San Luis Valley got along alright under this staggering <br /> <br /> <br />salt load. <br /> <br />-8- <br />