Calculate the change in storm water runoff in cubic feet per second caused by building a house on the Noblesville, IN lot assuming the following conditions. Use these tables and type only the number in the field below. (43,560 ft2/acre)
Ø Pre-development
o a 100 year, 1 hour design storm. Rainfall intensity – 3.05 in/hr
o Assume that 90% of the 0.5 acre lot is concrete pavement and 10% is grass lawn (flat, well drained, sandy soil)
o Use average values for pre-development coefficients
Ø Post development
o Plans include a two story house with a 1500 sq. ft. foot print and about 500 sq. ft. of concrete driveway, deck, and sidewalk.
o The remainder of the lot will be planted with grass lawn (flat, well drained, sandy soil).
o Use worst case coefficients for impervious developed surfaces and average values for other surfaces.