WSP11356 - Laserfiche WebLink

Home Browse Search

r ~ (", 'i ~,~ "" t 4.6 METROPOLITAN WATER DISTRICT a very uniform quality of finished water. In table 9 are given the data on operation of the cation exchange softener units. Chemical control of the quality of water maintained through- out the softening process required the analysis of approximately 13.000 samples taken at various stages in the process. In addition, 1,444 samples were taken at the plant for bacteriological examina- tions. From points in the distribution system, 753 samples were taken for chemical analysis and 7,979 samples were collected for sanitary control. The observation and control of plankton growths in the various District reservoirs required the microscopical exam- ination of 1,572 samples. The practice of spot treatment with copper sulfate to control scattered growths was continued with successful results. No general treatment of Lake Mathews was required during the fiscal year. The results of bacteriological examinations of Colorado River water are given in table 10. From natural Colorado River water 10.9 per cent of the 10-ml. tubes planted showed positive in the completed test, representing a decrease from the corresponding figure for the preceding fiscal year. From the 1,805 tubes planted from the softened water samples taken at the plant, no positive completed tests were obtained. Thirty-four completed tests were obtained from the distribution system samples collected, represent- ing less than 1/10 of one per cent of the 39,895 tubes planted, lhliL'cry of C(,[orar!n Hir('r wolf''' Sales of softened Colorado River water to constituent areas of the District, as given in table 11, were considerably greater than in the previous year, showing an increase of 33 per cent. All constit- uents, vv"ith the'exception of Pasadena, showed increases in varying amounts, ten incl~easing their purchases to record annual totals. San Marino used no District water and Compton only a small amount. The daily sale of softened water for the fiscal year averaged 237.2 acre-feet, equivalent to 119.6 cubic feet per second or 77 million gal- lons per day. The maximum monthly delivery of softened water to constituent areas was 15,188 acre-feet in August 1951, and the min- imum 3,319 in January 1952. In February 1952, delivery of surplus water was begun to five Monk Hill water companies in the Altadena-La Canada area under agreements which provided for the sale by the District of surplus softened water to be transported by the City of Pasadena through its system. A delivery of 420 acre-feet of softened water was made to the City of Los Angeles for the account of Southern California