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<br />38 <br /> <br />. <br /> <br />for streams such as the one surveyed. A comparison of profiles is <br /> <br />included in Appendix E. Profiles for flows near critical, computed <br />by the USBR program and program PR$FILE, are compared to the <br />measured profile. PointS at which the USBR program Was unable <br />to continue computation are also noted. Profiles for flows in the <br />subcritical zone (Fr ~ 0.1 - 0.6) were compared using the USGS, <br />USBR and PR~FILE programs. These arEi also shown in Appendilt E. <br />Adjustments in values of roughness were found to be necessary <br />for each of the programs in order to achieve comparable results. This <br />was undoubtedly caused by differences in the ways each of the programs <br />computes energy loSses. The largest values of roughness were used <br />in the USGS program, while roughness in the USBR and PR$FlLE <br />programs were essentially the same, since energy losses are computed <br />similarly in the latter two programs. All values used~for roughness <br />were generally higher than the original estimates. This is most <br /> <br />likely due to a need to account for bend losses. A comparison of <br /> <br />the roughness values used and those estimated is shown in Table 4-1. <br /> <br />. <br /> <br />. <br /> <br />~ <br /> <br />. <br /> <br />Table 4-1 <br />Comparison of Manning's "n" values used in each program <br /> <br />0.023 <br />0.030 <br />0.035 <br /> <br />USGS Program <br />0.028 <br />0.036 <br />0.041 <br /> <br />USBR Program <br />0.026 <br />0.034 <br />0.038 <br /> <br />~ <br />0.026 <br />0.033 <br />0.038 <br /> <br />Estimated <br /> <br />. <br /> <br />As indicated on the comparison plots in Appendix E, all of the <br /> <br />programs are capable of computing a reasonable approximation to the <br />