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<br />42 <br /> <br />Chapter V <br />CONCLUSIONS AND RECOMMENDATIONS <br /> <br />Applicability of the Program to the Problem <br />The objective of this study was to provide a computer-oriented <br /> <br />method of backwater curve computation for streams whose flows are <br /> <br />near critical. In seeking the solution, programs developed by three <br /> <br />governmental agencies were found to be germane to the water surface <br /> <br />profile problem. Of the three agencies, USGS, USBR and USeE, two <br /> <br />had programs which Were possible to apply toward solution of the <br /> <br />problem with available computer equipment. The USCE program proved <br />too large (in excess of 65,000 address core storage) and complex for <br />convenient handling on the available CDC 6400 computer. The USGS <br />program worked well for flows well below-critical, but failed to carry <br /> <br />on calculations when the Froude number exceeded about 0.7. The USBR <br /> <br />program worked satisfactorily on flows in the critical range, but was <br /> <br />not able to continue computation for reachea of large energy changes <br /> <br />(greater than 32 feet of head). Each of the three programs had <br />certain desirable aspects in methods of calculation and data handling, <br /> <br />so they contributed substantially to the development of program PR~FILE. <br /> <br />Program PR~FILE uses a conventional method of computing water <br /> <br />surface profiles, which is based upon a computerized version of the <br /> <br />Standard Step Method. Because the Standard Step Method may not be <br /> <br />able to calculate an energy balance at flows near critical, a special <br /> <br />computation routine is included in the program which will continue <br /> <br />calculations for such flows. If flow is sufficiently close to critical <br /> <br />that an energy relationship with an adjacent section cannot be <br />