$206$ Chapter $7$ Infiltration

$7\mathrm{.}9$ Tabulated below are total rainfall intensities during each hour of a frontal storm $OVe{F}_a$ drainage basin.

a$.$ Plot the rainfall hyetograph $($intensity versus time$).$

b$.$ Determine the total storm precipitation amount in inches.

c$.$ If the net storm rain is $2\mathrm{.}00$ in$.,$ determine the exact $$ index $($in$./$hr$)$ for the drainage basin. $($Note that by definition the area under the hyetograph above the $$ index must be $2\mathrm{.}00$ in$.)$

d$.$ Determine the area of the drainage basin $($acres$)$ if the net rain is $2\mathrm{.}00$ in$.$ and the mea. sured volume of direct surface runoff is $2,015cfs-hr.$

e$.$ Using the $$ index calculated in part $c,$ determine the volume of direct surface runoff $($acre$-$ft$)$ that would result from the following:

$\backslash$table$[[$Hour$,1,2,3,4],[$Intensity $($in$./$hr$),0\mathrm{.}40,0\mathrm{.}05,0\mathrm{.}30,0\mathrm{.}20]]$

$\backslash$table$[[,$Rainfall intensity $($in$./$hr$),$Hour,Rainfall intensity $($in$./$hr$)],[$Hour$,$Rat,$0\mathrm{.}15,],[1,0\mathrm{.}41,13,0\mathrm{.}23],[2,0\mathrm{.}49,15,0\mathrm{.}28],[3,0\mathrm{.}22,16,0\mathrm{.}26],[4,0\mathrm{.}31,17,0\mathrm{.}21],[5,0\mathrm{.}22,18,0\mathrm{.}09],[6,0\mathrm{.}08,19,0\mathrm{.}07],[7,0\mathrm{.}07,20,0\mathrm{.}06],[8,0\mathrm{.}09,21,0\mathrm{.}03],[9,0\mathrm{.}08,22,0\mathrm{.}02],[10,0\mathrm{.}06,23,0\mathrm{.}01],[11,0\mathrm{.}11,24,0\mathrm{.}01],[12,0\mathrm{.}12,,]$Use the first table