Calculate synthetic triangular unit hydrograph using SCD method for a $40$ acre development with $75\%$ as residential of $1/4$acrr properties and $25\%$ as commercial properties. Site has Type B soil throughout. Slope is $3\mathrm{.}5\%$ with a sustem length of $2000$ft$.$

I. Determine Curve Number

II$.$ Determine time base $($in hours$)$ of unit hydrograph

III. Determine peak unit discharge $($in cfs$/$in$)$