Worked Problems

$4.$ Given a watershed with a $4$ sq$.$ mile are in which $35\%$ is hydric soil group $C$ and the remainder is group B and in which $80\%$ of the area is forest and the rest is $\frac{1}{2}$ acre residential, and where the $80\%$ forest is evenly split between the two soil groups and the $\frac{1}{2}$ acre residential is all in group C $,$ compute the peak discharge for a $10-yr$ rainfall even with a total depth of $3\mathrm{.}9$ inches.

a$.$ Assume $150$ feet of sheet flow with a linear slope of $1\mathrm{.}5\%$

b$.$ Assume that the shallow concentrated flow is all in the forested area with a length of $2,700ft.$ and a linear slope of $2\%.$

c$.$ Assume that the channel is V shaped, grass lines, with $2$:$1$ side slopes and a top width of $4$ ft $,$ and a linear slope of$.1\%$ and a length of $1,500ft.$

d$.$ Assume zero ponding.

e$.$ Assume a Type II distribution

f$.$ Assume the $2-$yr rainfall is $1\mathrm{.}3$ inches.

$5.$ Create a center weighted storm hyetograph from the following precipitation intensity data.

$\backslash$table$[[$Time $(min),$Intensity $(i\frac{n}{h}r)$