This scenario is meant to model a peak flow discharge situation that may have existed before human development impacted this drainage basin.  For this hypothetical scenario I have chosen to examine a completely forested watershed.  It is possible that the climax vegetation is not forest for the entire watershed but it is impossible to know exactly what the comosition would have been before human influence.  Based on the current extent of the forest cover, it is reasonable to assume that most of the region would have been forest.

Since there is only one land use category in this scenario, it was the simplest of the four scenarios to calculate.  The CROSSTAB module was used to identify all the unique combinations of soil and slope layer categories.  The resulting crosstab classes were entered into an Excel table.  After running the AREA module, the area values were then entered into the table as well.  Excel was used to perform the last steps:  calculating the proportional area of each class, calculating the weighted runoff coefficient of each class and then summing them to give the coefficient of runoff for the entire basin.
 
 

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