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<br />. <br /> <br />~..... <br />-.J <br />w <br />O'..l <br /> <br />. <br /> <br />. <br /> <br />Maximum depth at time of measurement and the nature and <br /> <br /> <br />distribution of various substrate are determined by <br /> <br /> <br />wading, floating, or boating across the stream along the <br /> <br /> <br />line of the cross.section. <br /> <br />5' <br /> <br />Calculation of Coordinates <br /> <br />Once the cross-section line has been established, measure- <br />ments are taken for cal cul at i ng the coordi nates. The <br />observor selects a point (P) either upstream or downstream <br />from the cross-section. This point, as long as it is at a <br />distance from the cross-section 1 ine greater than the <br />mi nimum range of the rangefi nder, may be located wherever <br />convenient for sighting in on the stakes. The following <br />measurements are made and recorded: <br /> <br />a' azimuth, using hand compass, <br /> <br />b' distance, using rangefinder, and <br /> <br />c' elevation in degrees + or -, using Abney clinometer. <br /> <br />Incidentally, as a check against subsequent calculations, <br /> <br /> <br />the distance AD is also read using rangefinder. The <br /> <br /> <br />location of the point of maximum dpeth is generally <br /> <br /> <br />measured directly as distance out from nearest water' 5 <br /> <br />edge. <br /> <br />26 <br />