For a design storm specified for an urban area in Tennessee, the depth of rainfall is 2.5 inches (6.35 cm). Initial abstraction in depressions on the pervious and impervious areas was estimated at 0.5 inches (1.27 cm). Infiltration was estimated as 1.0 inch (2.54 cm) using the double-ring infiltrometer. Determine a)the rainfall excess in cm? b) the volume of runoff for a 10.0 acre (4.05 hectare) area in cubic meters?