Use the NRCS $($SCS$)$ Method to estimate the direct runoff from a $6-$hr rainfall event

with $5in.$ of total precipitation over a $100$ acre watershed. The Area is subdivided by soil

type and land use conditions as presented in the table. Consider that the antecedent moisture

condition of the watershed soil before the event is saturated.

Determine $($show your computations$)$:

A$)$ Curve numbers

Curve number for each area for average AMC and the corresponding

composite curve number for average AMC conditions on the total

watershed area.

Corresponding composite curve number for the total watershed area under

saturated conditions for the AMC.

B$)$ Estimate the following terms in your total $6-$bretorm rainfall event:

Estimated potential maximum retention of the total watershed $($in$.).$

Initial abstractions estimated by this method for the total watershed $($in$.).$

Total Surface Runoff of the total watershed $($in$.).$

C$)$ If the storm event is divided in three periods of $2$ hours increments as shown in the

following table, compute the direct runoff $=$ rainfall excess during each period$(in.){?}_{(})$