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<br />'<:1' <br />r-- <br />CD <br />o <br />,-. <br />-- <br /> <br />c\ <br /> <br />The seepage rates calculated from the inflow-outflow measurements <br /> <br />exhibited large variations from lateral to lateral without any apparent <br /> <br />spatial correlation. Commonly, the seepage rate of a specific lateral varied <br /> <br />greatly between the two measurements. <br /> <br />To investigate the effect of gross inaccuracies in flow measurement, <br /> <br />data from Test No. 1 (Table 3) were evaluated assuming that the higher value <br /> <br />of flow was 5 percent high and that the lower value ~f flow was 5 percent <br /> <br />low. This exercise yielded a mean seepage rate of 1.52 feet per day with a <br /> <br />standard deviation of 5.1 indicating that the accuracy of even the best <br /> <br />available flow measurement is insufficient for seepage tests. Inflow-outflow <br /> <br />tests do indicate whether a reach is gaining or 10sil1g water. <br /> <br />In April 1978, prior to diverting water into the Government Highline <br /> <br />system, 16 shallow well pump in tests were conducted at 4 sites on 3 laterals <br /> <br />in the Reed Wash area. The conductivity values obtained were weighted in <br /> <br />accordance with the geometry of the wetted perimeter as measured by a <br /> <br />cross-section survey made in conjunction with the ponding tests. Using the <br /> <br />equation, <br /> <br />K (B+2d) <br /> <br />q <br /> <br />= <br /> <br />, where: <br /> <br />3.5 <br /> <br /> q is the seepage in cubic feet per foot of channel per day, <br /> K is the hydraulic conductivity adjacent to the channe 1, <br /> d is the normal water depth in feet, <br /> B is normal top width in feet, <br />seepage rates of 1. 3 ft 1ft Iday, 0.33 ft 1ft Iday, and 1.82 ft 1ft Iday were <br /> <br />calculated for 44, 45, and 47 1/4, respectively. <br /> <br />13 <br />