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»»>RATIONAL METHOD INITIAL SUBAREA ANALYSIS««< <br />»USE TIME -OF -CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< <br />INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00 <br />ELEVATION DATA: UPSTREAM(FEET) = 156.50 DOWNSTREAM(FEET) = <br />154.50 <br />Tc - K*[(LENGTH" 3.00)/(ELEVATION CHANGE)]"0.20 <br />SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.000 <br />* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 6.187 <br />SUBAREA Tc AND LOSS RATE DATA(AMC II): <br />DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap <br />SCS Tc <br />LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) <br />CN (MIN.) <br />COMMERCIAL B 0.77 0.30 0.100 <br />56 5.00 <br />SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.30 <br />SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100 <br />SUBAREA RUNOFF(CFS) = 4.27 <br />TOTAL AREA(ACRES) = 0.77 PEAK FLOW RATE(CFS) = 4.27 <br />a aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa <br />FLOW PROCESS FROM NODE 301.00 TO NODE 302.00 IS CODE = <br />91 <br />»»>COMPUTE PIPE -FLOW TRAVEL TIME THRU SUBAREA««< <br />»»>USING USER -SPECIFIED PIPESIZE (EXISTING ELEMENT) ««< <br />---------------------------------------------------------------------------- <br />ELEVATION DATA: UPSTREAM(FEET) = 148.00 DOWNSTREAM(FEET) = <br />147.00 <br />FLOW LENGTH(FEET) = 251.00 MANNING'S N = 0.013 <br />ASSUME FULL -FLOWING PIPELINE <br />PIPE -FLOW VELOCITY(FEET/SEC.) - 5.43 <br />PIPE FLOW VELOCITY = (TOTAL FLOW)/(PIPE CROSS SECTION AREA) <br />GIVEN PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1 <br />PIPE-FLOW(CFS) = 4.27 <br />PIPE TRAVEL TIME(MIN.) = 0.77 Tc(MIN.) = 5.77 <br />LONGEST FLOWPATH FROM NODE 300.00 TO NODE 302.00 = 351.00 FEET. <br />+ <br />+ <br />DA-C2 <br />---------------------------------------------------------------------------- <br />a aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa <br />FLOW PROCESS FROM NODE 310.00 TO NODE 310.00 IS CODE = <br />82 <br />»»>ADD SUBAREA RUNOFF TO MAINLINE, AT MAINLINE Tc, ««< <br />»»>(AND COMPUTE INITIAL SUBAREA RUNOFF) ««< <br />---------------------------------------------------------------------------- <br />INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00 <br />ELEVATION DATA: UPSTREAM(FEET) = 156.50 DOWNSTREAM(FEET) = <br />154.50 <br />Tc - K*[(LENGTH" 3.00)/(ELEVATION CHANGE)]"0.20 <br />SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.000 <br />* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 6.187 <br />SUBAREA Tc AND LOSS RATE DATA(AMC II): <br />DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap <br />SCS Tc <br />LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) <br />CN (MIN.) <br />COMMERCIAL B 2.09 0.30 0.100 <br />56 5.00 <br />SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.30 <br />SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100 <br />SUBAREA AREA(ACRES) = 2.09 INITIAL SUBAREA RUNOFF(CFS) = <br />11.58 <br />" ADD SUBAREA RUNOFF TO MAINLINE AT MAINLINE Tc: <br />MAINLINE Tc(MIN.) - 5.77 <br />* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.700 <br />SUBAREA AREA(ACRES) = 2.09 SUBAREA RUNOFF(CFS) = 10.66 <br />EFFECTIVE AREA(ACRES) = 2.86 AREA -AVERAGED Fm(INCH/HR) <br />= 0.03 <br />AREA -AVERAGED Fp(INCH/HR) = 0.30 AREA -AVERAGED Ap = 0.10 <br />TOTAL AREA(ACRES) = 2.9 PEAK FLOW RATE(CFS) = <br />14.59 <br />a aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa <br />FLOW PROCESS FROM NODE 310.00 TO NODE 320.00 IS CODE = <br />91 <br />»»>COMPUTE PIPE -FLOW TRAVEL TIME THRU SUBAREA««< <br />2 <br />