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<br />8 <br /> <br />TECHNIQUES OF WATER-RESOURCES INVESTIGATIONS <br /> <br />/ " <br /> x-5e t. 4 <br /> n -0.0 80 n' 0+5 0 <br /> Pr:i'hl""'$1J n. o.04f> J-P' <br /> Coo !Jers <br /> 0 <br /> X-Se t.3 <br /> n'O.OSO n,D. <5 <br /> "'?~6r::;- n. ao+~ !J,lt 0 <br /> c<>6b/~r m<l/f bov clerS <br /> X-Se "2 <br /> n,O.08 <br /> "'9'Ii"6r" n. 0.045 k~ <br /> ,,6bf~ C m"" Do" d~r$ <br /> x- Se To I 0 <br /> ~~ n. 0.045 fl' <br /> C bblels ,,7rboul .'5 0 <br /> Plnin . < Sm 'fh of r:::ecr. I <br /> Phofc,# ~ Sm "fh at- ';ecf: 4- 0 <br />~% / <br /> <br />SnaKe Creek near Connell. Wash. <br /> <br />. <br /> <br />o <br /> <br />Flood 01' 2 21 S6 Surve .3 20 '5~ <br /> . <br /> , <br /> , <br /> , R <br /> ~ <br /> , <br /> '" . <br /> , , <br /> * <br /> 0 <br /> , ., <br /> , <br /> . - 3 <br /> , , <br /> , - - <br /> < <br /> , , <br /> ~ <br /> 0 <br /> , , <br /> , <br /> , <br /> , 0 <br /> I <br /> <br />. <br /> <br />o <br /> <br />o <br /> <br />o <br /> <br />o <br /> <br />o <br /> <br />Figure 4.-Sample: Reid notes illustrating sketches of reach and C:I'O$$ sections. <br /> <br />Ik, <br /> <br />2. Measure distance from hub 2 to tele- <br />scope horizontal axis as 4.34 (record on line 15) . <br />Sight on station 1, read back azimuth, stadia <br />distance, and rod (line 16). <br />3. Compute elevation of HJ. (1) by <br />adding previously determined elevation of hub <br />1 (20.08) and backsighton hub 1 (1.65) j (2) by <br />adding previously determined elevation of hub <br />2 (17.37) and distance above hub 2 (4.34). <br />Average of 2 computed HJ.'s is 21.71 feet <br />(line 13), which is balanced elevation. Com- <br />pute balanced elevation of hub 2 from H.I. of <br />21.72 as 17.38 (line 15). <br />4. Take readings on all side shots, then <br />on next setup location, transit station 3. <br />Tighten upper clamp on azimuth to station 3, <br />loosen lower clamp, move to station 3. <br /> <br />Surveying equipment <br /> <br />Standard types of surveying equipment are <br />most commonly used. For most work, the usual <br /> <br />engineer's transit, with a telescope of 18-24 <br />magnification, is satisfactory. Light mountain <br />transits have been used extensively for this <br />work. On large-scale surveys, involving long <br />traverses, it may save time and expense to obtain <br />the use of a high-powered instrument which <br />allows much longer sight distances. The Zeiss <br />Opton level is being used in regulation indirect- <br />measurement work. This is a high-powered <br />rugged compact level with an automatic self- <br />leveling feature which speeds up leveling work; <br />it also has a horizontal circle which is read <br />through an auxiliary eyepiece. The enclosed <br />optical system does not fog up when working <br />in the rain. The one major disadvantage is the <br />inability to turn the telescope vertically, as in <br />using the "stepping method," or in orienting on <br />a distant point. Another disadvantage is lack <br />of a compass. <br />Standard level rods of either the Philadel- <br />phia or Chicago types are usually used. A 16- <br />foot rod has been found advantageous. A <br /> <br />.. <br />