Question $4$:

$($a$)$ Draw a typical streamflow hydrograph and show and write down all of its components. $(5$ points$)$

$($b$)$ The ordinates at $1-$hr interval of a $1-$hr unit hydrograph are $0,200,600,500,300,100,$ and $0$ cfs$.$

$($i$)$ Determine the direct runoff hydrograph from a $3-$hr storm in which $0\mathrm{.}5"$ in of excess rainfall occurred in the first hour, ${1\mathrm{.}5}^{\text{'}\text{'}}$ in the second hour, and $2\mathrm{.}0"$ in the third hour.

$($ii$)$ What is the area of the watershed in $m{i}^2$ with at least three decimal places? For full points, show calculation steps with all columns and sample calculations clearly. $(20$ points$)$