$(15$points$)$ Find the resultant force and the center of pressure$($measured from the river bottom$)$ for the $85$ foot wide $($measured perpendicular to the cross$-$section, i$.$e$.,$ in an out of the paper$)$ sheet pile cofferdam illustrated in the section below. Assume the specific weight of seawater is $64\mathrm{.}00l\frac{b}{f}{t}^3.$

FBD $(3)$

Resultant Force $=F_r=$

kips $(7)$

Center of pressure above river bottom $=y_x=ft(5)$