Laserfiche WebLink
<br />I <br /> <br />I <br /> <br />~~~8 <br /> <br />HYDROGRAPHY <br /> <br />67 <br /> <br />Use of the lower gates then continued, except for a few weeks in <br />July and August 1950, until about the middle of June 1952. Such <br />discharge from the lowe,' gates is desirable and necessary. of <br />course, whenever the depth of water in Lake Mead makes such <br />operation practicable. in order to prevent so far as possible the <br />accumulation (due to its relatively greater specific gravity) of <br />more-saline water in the bottom strata of the reservoil'. But the <br />effect is promptly noticed downstream in changes in water quality, <br />Based 011 monthly water samples at the aqueduct intake, as <br />analyzed at the District laboratory at La Verne, a summary of <br />recent water quality data and signifIcant changes therein is tabu- <br />lated for comparison. <br /> <br />COLORADO RIVER (LAKE HAVASU) AT AQUEDUCT INTAKt; <br />Anal}"~{,1il in Paris Iler Million <br /> <br />8.12 <br />37 <br /> <br />FISCAL YEARS <br />19.50.;;1 19.51.52 <br />6,12 6.5.1 <br />3],1) .322 <br />129 127 <br />186 ]9" <br />269 230 <br />73 77 <br /> <br />999 1027 <br />38 39 <br /> <br />8.3 8..1 <br /> <br />C.URR[,NT <br />1\f,UIMuM l\hNIMUI'rI <br />6-17-52 B-9.52 <br /> <br />677 6]2 <br />338 299 <br />l.32 Hi <br />206 182 <br />290 266 <br />81 70 <br /> <br />CON;,TITUF.NT <br />Tolal !'.olids. ............ <br />T(.tal hardness.. <br />Carhonate hanJnes~ ... <br />Nnncarbtlnate hardness.. . <br />Sulfate SOt .......... <br />Chloride 0.. ..... <br />Electrical conductivity. <br />K X ]O~ .............. .. <br />"Percenl sodium" .. .18 <br />Hydrogen (on C{lllr~n- <br />tratiol1 pH ........... III <br /> <br />REC<Hm <br />1\IAXJ:'olUM j\JINI~fU:o.t <br />'1.8.41 ]2.14-49 <br /> <br />8~" 5.11 <br />420 273 <br />Fi4 118 <br />266 1"5 <br />381 224 <br />89 56 <br /> <br />8..1 <br /> <br />1070 9"9 <br />38 ,19 <br />8.4 8.4 <br /> <br />Compared with the previous fiscal year, the change in water <br />quality at the aqueduct intake for 1951-52 was from 3 to 5 pel' cent <br />~ _ _ ____wOrSeJOLthe. .\'arious. items-of. -chief--imllortilnce;-€ompared;-how--- <br />ever, with the December 1949 quality, 1951-52 was 20 to 30 per <br />cent worse for the several items, but 18 to 26 per cent better than <br />~ the 1941 worst conditions of the record period. <br />During the July to September 1952 lleriod, fortunately. water <br />quality conditions at the aqueduct intake improved greatly. as a <br />I result of the above normal runoff into Lake Mead and the mentioned <br />change in June to use of the upper outlet gates. The effect of the <br />gate change was delayed about one month in reaching the aqueduct <br />intake, as compared with previous similar event., due to the pres- <br />ent operation of Davi, Dam and the substantial storage contents <br />(1,600.000 acre-feet) of its reservoir, Lake Mohave. The immediate <br />improvement as shown by the difference between the last two <br />columns of the above tabulation dated June 17 and August 9, 1952, <br />