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THEY WILL HAVE HIGHER RUNOFF CHARACTERIATICS . SOME DRAINAGE <br /> AREAS CONTAIN AREAS THAT HAVE BEEN UNAFFECTED OR <br /> REVEGITATED. THE COEFFICIENTS FOR THESE AREAS REFLECT THE <br /> COMBINATION OF HIGH AND LOW RUNOFF CHARACTERISTICS . THE <br /> REFUSE PILES , THOUGH NOT PRESENTLY VEGITATED, ARE RELATIVELY <br /> PERMIABLE AND WILL YIELD LITTLE RUNOFF. THE RUNOFF <br /> COEFFICIENTS FOR THESE AREAS HAVE , HOWEVER, BEEN ESTIMATED <br /> FOR THEIR FINAL REVEGITATED STATE WHICH WILL HAVE A GREATER <br /> RUNOFF POTENTIAL . <br /> THE RATIONAL METHOD OF STORM RUNFF CALCULATION WAS USED <br /> THROUGHOUT. AS RUNOFF FROM DIFFERENT AREAS REPORTS TO A <br /> GIVEN CHANNEL , THE TOTAL OF THE PEAK RUNOFF FLOWS WAS USED <br /> AS THE DESIGN FLOW FOR THE CHANNEL . RATHER THAN <br /> RECALCULATING A NEW, LONGER , SATURATION PERIOD AND LESSER <br /> FLOW, THIS CALCULATION YIELDS A SIMPLER AND MORE <br /> CONSERVATIVE DESIGN. ALL FORMULAS AND COEFFICIENTS FOR <br /> CALCULATING SURFACE RUNOFF CAME FROM HAAN AND BARFIELD. <br /> OPEN CHANNEL FLOWS WERE CALCULATED WITH MANNINGS EQUATION. <br /> ALL CULVERTS WERE DESIDNED TO RUN OPEN SO NO ADDITIONAL <br /> STRUCTURES WOULD BE NECESSARY TO PROVIDE HEAD TO THE PIPES . <br /> CMP-4 DOES HOWEVER RUN FULL ; THE HEAD IS PROVIDED BY THE <br /> DROP IN THE PIPE AND ONLY ENOUGH WATER TO INUNDATE THE <br /> ENTRANCE IS REQUIRED. IN CALCULATING PEAK RUNOFFS FOR THE <br /> INDIVIDUAL AREAS THE RAINFALL INTENSITY FOR A STORM DURATION <br /> EQUAL TO THE TIME OF CONCENTRATION FOR THAT AREA AND HAVING <br /> A STORM OCCURANCE FREQUENCY OF TEN ( 10) YEARS WAS USED. <br /> 0 <br />