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<br />. <br /> <br />. <br /> <br />The hydrologic method used to calculate the lOO-year flood <br /> <br />shall be the most appropriate technique, considering the <br />availability of streamflow records, and rainfall-runoff <br /> <br />parameters. <br /> <br />The hydrologic analysis and the lOO-year flood discharge <br /> <br />shall be reviewed with the CWCB staff prior to proceeding <br /> <br />with the hydraulic analysis. The hydrology technique, and <br /> <br />and the data used to calculate the lOO-year discharge <br /> <br />shall be well documented in the technical addendum. <br /> <br />Hydraulic Analysis <br /> <br />The 100-year flood profile shall be calculated and the 100- <br /> <br />year floodplain delineated on topographic maps. Flood profiles <br /> <br />shall be calculated by the standard step method employing the <br /> <br />Bernoulli energy equation with energy losses due to friction evalu- <br /> <br />ated with the Manning equation, and other losses evaluated by the <br /> <br />shock loss equation or other acceptable methods. <br /> <br />I} <br /> <br />~J-.rr-\ (' ,~-vJ <br /> <br />VVJ/VV\ ~_, 0 r ~ - S<' (' 6",_..,.~ 5 ~~--e2. ~ <br />) j -1 . <br />7:.;0 oj:le9vQ, "_'/, dy, ~ <br /> <br />f +-~ ~~U'-~'1 (r',..,.,-of-., <br /> <br /> <br />U.AQ.d \'^ +\~n \")-1,1/-,..P..:'" r.'-~--"c'j),.(S'I!' <br />--t,^". \..-."'1 rl. ~Oy.o.'" 0. ('--\"'<-ie" r l<.(.~~-f Ie:> 0 <br /> <br />consideration any alteration in the channel subsequent to the floods. <br /> <br />If there are stream gaging stations within the study reach the com- <br /> <br />puted water surface profiles shall be checked against the station <br /> <br />rating curve. <br /> <br />An acceptable method for computing the flood profiles includ- <br /> <br />lng bridge and culvert crossings is the "HEC-2, Water Surface <br /> <br />Profiles" Computer Program developed by the U. S. Army Corps of <br /> <br />-5- . <br />