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<br />OJ07GS <br /> <br />~~ti <br /> <br />~$ <br /> <br />Measurements of Water Table Position <br /> <br />The water table measurements were obtained with a chalked steel addtape to <br />the nearest 0.01 foot. The measurements were taken over the entire traverse at <br />a frequency dependent upon the expected I:ates of rise and fall of the mound. <br />Appendix table 1 gives the data in the form of each well's rise above a I:efer- <br />ence head determined as an avel:age of a number of readings taken prior to the <br />start of spreading and corrected for atmospheric pressure changes (2), for pond <br />No. 1 at the University of California Westside Field Station at Five Points. <br />Appendix table 2 contains data from each well at pond No.2, near Cantua Cl:eek, <br />10 miles west of Five Points. In Appendix table 2 (pond No.2) the wells desig- <br />nated with "A" (that is, 3A, SA, . . .) refer to shallow wells that were added <br />at locations 3, 5, . . . (fig. 2) after the neutron probe access tube P-l showed <br />that perching was occurring in the profile above the pre-existing water table. <br /> <br />Effect of Perching Upon Water Table Observations <br /> <br />A plot of the observed rise in head over the initial water table level for <br />comparing deep and shallow wells is shown in figure 3. This plot includes ob- <br />servations during both the rise and fall of the mound. The ratio of head rise <br />deep to head I:ise shallow is constant through the range. As seen in figure 4, <br />this slope approached a value of 1.00 outside the pond boundaries and 1.50 with- <br />in the pond. So the perching phenomenon waS confined to the area beneath the <br />pond where the direction of flow was closest to vertical. Drilling the central <br /> <br /> <br />9 <br /> <br />8 <br /> <br />+:: RISE <br />0" FALL <br /> <br />7 <br /> <br />VS 12A <br /> <br />I- <br />w <br />w 6 <br />~ <br /> <br />, <br />-' <br />-' <br />~ 5 <br />~ <br />o <br />-' <br />:;t 4 <br />~ <br />V> <br />;; <br />'" 3 <br />V> <br />" <br /> <br />vs 17A <br /> <br />2 <br /> <br />X:: RiSE <br />.:: FAl-L <br /> <br />I 2 3 4 <br />RISE IN DEEPER WELL - FEET <br /> <br />5 <br /> <br />6 <br /> <br />Figure 3.--0bsel:ved rise in the shallow well compared with that in the deep well <br />for two sites. <br /> <br />4 <br /> <br />~'-"ff~.iit~ <br />~~~tfl~ <br />i~~:_:''''q;,......J]f!& <br /> <br />- ',~. <br /> <br />'"0'.". _ <br /> <br />,!j;;j',,~~r.:;;.~ <br /> <br />.~~ .~.:-:-; ,:,-;- <br /> <br />,"'. .- -. ~. <br />,,-.-,"..-.. <br /> <br />:;;-_;._.... ,'J;' <br />~:~:-r~>.~..::.;.~:__. :.)''::- <br /> <br />h_<..;;_.;" __". .... <br /> <br />. ...... <br />.. <br /> <br />.-. '~'- .".- -.'- <br /> <br />"'~;I~~~~i_.~fi~lIIf~i~i~~~ <br />