$\backslash [$

f$=7\mathrm{.}5+85\mathrm{.}5$ e$^\{-0\mathrm{.}0412$ t$\}$

$\backslash ]$

where $\backslash ($ t $\backslash )$ is in minutes and $\backslash ($ f $\backslash )$ is $\backslash (\backslash$mathrm$\{$mm$\}/\backslash$mathrm$\{$hr$\}\backslash ).$ Consider a storm of event of $120$ min in the same area with the following intensities:

Determine the following quantities:

a$)$ Effective precipitation depth

b$)\backslash (\backslash$Phi $\backslash )-$index

c$)$ Total infiltrated amount of water.

$[$Answers: a$)71\mathrm{.}1$ mm a$)39\mathrm{.}2$ mm b$)\backslash (21\mathrm{.}6\backslash$mathrm$\{$~mm$\}/\backslash$mathrm$\{$h$\}\backslash )]$

Problem $2$: Consider a watershed area in class B soil of $1000$ acres of which $400$ acres is forest with slope of $\backslash (5\backslash \%,500\backslash )$ acres is flat agricultural land, and $100$ acres is urban.

a$)$ Using the table given, compute the CN parameter for the watershed.

b$)$ For the same watershed above, use the Curve Number Method to calculate the flow rate $($Q$)$ at the discharge point for the rainfall data below. $($Hint: The table below shows the steps of calculations$).$