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<br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />GENERAL FIELD AND OFFleE PROCEDURES FOR INDIREeT DISCHARGE MEASUREMENTS 5 <br /> <br />/ " <br />Sia. A,im. Disr. Rod Eleot/. <br />""^.N O~OO' - - <br />RP2 202~3() 16 If.07 /4./5 0 <br />".... r H r. . 2 1<>.22 <br />0/ - 0 (5./4 20.08 0 <br />lBr.R. ?34-2 /80 5.47 jq.75 <br />HW/Vf 234-50 /85 5.QQ 19.23 <br /> 208.50 0 <br /> /9.06 <br />FP2 202] /6 //.06 /4./6 <br />D2 67-23 4060 P"~/. <br />7.85 ~ t:/~v. <br />~ 2 HI = 20.084 .65-21.7 = 2/.72 <br />17.37+ .34-'21.7 <br />Moo.N 0-01. <br />02 - 0 (".34- 17.38 <br />0/ 21-7-24 462 1.65 0 <br />HWM 249-4' 420 2.60 N. /2 <br />oj /24-2/ 2% 2.11 4-'1-/.1 pr.:{. <br />E/~v, <br /> 0 <br />7CJ HL= f7.:J8+6 62-2+. ~=24. 0 <br />1'1,6/+ .,.. 40=2;4-. <br />Man,N 0-0/ <br />0.3 - 0 (4.40) 19.60 0 <br />02 1?04c22 2QS 6.62 <br />'- / <br /> <br />Goose R/ver near M-anha Nan, 7efln. <br /> <br />o <br /> <br />/0 doF I. urve 2 . <br /> " , , 4" <br /> , <br /> .: n <br />" I, 06 , <br />a s <br />, 0 , I <br /> ch <br />t <br />s i e i <br /> <br />o <br /> <br />o <br /> <br />o <br /> <br />o <br /> <br />o <br /> <br />Figure 1.-Sample field notes illustrating system of horizontal and vertical control, with no instrument error. <br /> <br />1. Set up exactly halfway between A and B. <br />Take a rod reading a on stake A and a rod <br />reading b on stake B. The computed ele- <br />vation difference, a-b, is the true differ- <br />ence, regardless of instrument error. Set <br />up close enough to A so that a rod reading <br />can be obtained either by reading through <br />the telescope in reverse or by measuring up <br />to the horizontal axis of the telescope by <br />steel tape. Take ~ rod reading a on stake <br />A and a reading d on stake B. If the in- <br />strument is in adjustment, (a-d) will <br />equlll (a- b). If the instrument is out of <br />lIdjustment, compute wllitt the correct rod <br />rellding e on B should be (e=b+a-a) <br />and adjust the instrument to obtain that <br />reading. <br />2. Set up close to A on II line perpendieular to <br />line A-B, assume an elevation for A, take <br />bllcksight on A and foresight on B, and <br />compute elevation lit B. Set up close to <br />B on a line perpendicular to line A -B, take <br /> <br />backsight on Blind foresight on A. The <br />closure difference represents the instru- <br />ment error in twice the distance between <br />A and B. Compute the balanced elevlItion <br />at B and the required foresight lit A to ob- <br />tain the correct starting elevlltion. Adjust <br />the instrument to obtllin the required <br />foresight. <br /> <br />Adjustment of instrument <br /> <br />All surveying instruments should be main- <br />tained in good adjustment. Full testing and lId- <br />justment is best done before tllking the instru- <br />ment into the field. Some highly specialized or <br />delioote instruments mllY require II skilled tech- <br />nician for mlljor lIdjustment. Proper oore and <br />handling will reduce the need for adjustment <br />in the field. The transitman should know the <br />characteristics of the pllrtieular instrument he <br />uses and be familiar with the routine adjust- <br />ments thllt can be made in the field. Keep the <br />manufacturer's hllndbook or lIn lIdequllte sur- <br />