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RUNOFF AND CHANNEL FLOW CALCULATIONS <br />• ~ PROGRAM NARRATIVE <br />ALL RUNOFF AND CHANNEL FLOW CALCULATIONS WERE PERFORMED BY A <br />PROGRAM DEVELOPED BY CF 6I FOR USE ON A HEWLETT-PACKARD 41-C <br />MICRO-COMPUTER. THE CALCULATION PRINT-Ol1TS ARE INCLUDED <br />WITH THIS REPORT. ALL FORMULAS FOR THE RUNOFF CALCULATIONS <br />CAME FROM fIYDROLOGY AND SFDIMENTOLOGY OF SURFACE MINED <br />AND BY C.T. HAAN AND 6.7. BARFIELD. (19TH). RAINFALL DATA <br />WAS FROM TECHNICAL PAPER NQ. 40. RAINFALL FREQUENCY ATLAS <br />OF THE UNITED STATES BY THE U.S. DEPARTMENT OF COMMERCE. <br />WEATHER BUREAU. (1961). <br /> IN DETERMINING PEAK RUNOFF FLOWS FOR THE VARIOUS DRAINAGES <br /> IT 41AS FIRST NECESSARY TO ESTIMATE RAINFALL INTENSITIES FOR <br /> THE RAINFALL DURATIONS WHICH 'dOULD EQUAL THE TIMES OF <br /> CONCENTRATION FOR THE DRAINAGE BAISNS TO BE EVALUATED. THAT <br /> IS TO SAY THAT EVERY DRAINAGE CHARACTERISTICALLY HAS A <br /> DEFINITE TIME IN WHICH THE ENTIRE SURFACE IS SATURATED ANO <br /> CONTRIBUTING RUNOFF TO THE COLLECTING DRAINAGE. THIS TIME <br /> IS DEPENDANT ON THE INTENSITY OF THE STORM. <br /> CHARACTERISTICALLY STORM EVENTS HAVE A HIGHER INTENSITY AS <br /> THEIR DURATION DECREASES. WITH THE TIME OF CONCENTRATION <br /> AND THE REQUIRED STORM INTENSITY BEING DEPENDANT OPI ONE <br /> ANOTHER, TRIAL TIMES OF CONCENTRATION WERE TESTED TO <br /> CALCULATE THE RAINFALL INTENSITY REQUIRED TO SATURATE THE <br />• AREA. THE TIME OF CONCENTRATION AND THE CALCULATED <br /> INTENSITY MOST NEARLY MATCHING THE RAINFALL DURATION- <br /> INTENSITY CUf•VE FOR STOf:MS IN THE WFSTON. COLORADO. AREA <br /> 29 <br />