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<br />30 <br /> <br />Table 14. Direct comparison of the R-2 Cross and IFG4 methods <br />for best accuracy in predicting field velocity measure- <br />ments. <br /> <br /> Model Number Percentage <br />R-2 Cross Error < lFG4 Error 37 47.4 <br />IFG4 Error < R-2 Cross Error 41 52.6 <br />TOTALS 78 100.0 <br /> <br />A fourth comparison involved the magnitude of error between <br />predicted and measured velocities determined at high and low dis- <br />charge calibration flows (Table 15). High (>lOQcfs) and low <br />(<10' cfs) calibration flows (Qs) refer to the highest and lowest <br />discharges measured on an individual stream during the 1978 field <br />season. In this comparison, the percentage of error between pre- <br />dicted and measured average velocities was the same at high and <br />low calibration flows with the R-2 Cross Method. Fifty percent <br />of the time the error in predicted average velocities was greater <br />at a high rather than low discharge flow and vice versa. This <br />could be interpreted to mean that the R-2 Cross Method worked <br />equally well (or bad) at high and low discharges. <br /> <br />Table 15. Comparison of the R-2 Cross and IFG4 methods for the <br />magnitude of error between average predicted velocities <br />and field measured average velocities determined at <br />high and low calibration flows. <br /> <br /> High Q error<low Q error High 0 error>low Q error <br />Method N percent N percent <br />R-2 Cross 15 50.0 15 50.0 <br />lFG4 26 72.2 10 27.8 <br />