IDF and PDF curves

For a given proposed project development in Puerto Rico, the annual maxima IDF curves are available as shown in the figure. To control the project runoff, you will design a retention pond at the current runoff exit of a $10-$acre project development area. The proposed maximum surface area of the pond is $1\mathrm{.}25$ acre and you need to determine if the pond water depth is less than the maximum allowable depth of $2ft.$ A simplified water budget analysis will be used to estimate the probable watershed runoff produced for storm durations presented in the table.

a$.$ For the recurrence $($frequency$)$ indicated in the table, use the IDF curve to obtain the rainfall intensity for each storm duration to then estimate precipitation depth.

b$.$ From these estimated precipitation depth values with the initial abstractions $($including the interception, evaporation and depression storage$)$ and the infiltration, estimate the runoff depth and its total volume of the simplified water cycle model.

c$.$ Then estimate the probable pond water depth if the surface area $=1\mathrm{.}25$ acre. $($You must complete the missing values of the table showing your equations and full computations$).$

$\backslash$table$[[100$ year,$],[$Time $($hr$),0\mathrm{.}5,1,1\mathrm{.}5,2,6],[$Time $($min$),30,60,90,120,360],[$Max Intensity $($in$./$hr$),,,,,],[\backslash$table$[[$Max Precipitation$],[$Depth $($in$)]],,,,,],[\backslash$table$[[$Interception and$],[$Depression Storage $($in$)]],0\mathrm{.}25,0\mathrm{.}25,0\mathrm{.}25,0\mathrm{.}25,0\mathrm{.}25],[$Infiltration depth $($in$.),0\mathrm{.}25,0\mathrm{.}45,0\mathrm{.}55,0\mathrm{.}6,0\mathrm{.}8],[$Surface runoff $($in$.),,,,,]]$

Runoff Volume $($acre$-$ft$)$

Required pond volume

for zero discharge $($ac$-$ft$)$

Required Pond Depth

$($surface area $=1\mathrm{.}25$ acre$)($ft$)$