16 Oct Creekbed Reconstruction After a Wildfire

In 2012, the Waldo Canyon fire burned 18,000 acres outside of Colorado Springs, CO.  After the fire, flooding risks increase drastically.  The Castle at Glen Eyrie, a historic structure built between 1871 and 1903 was at risk of flooding.  In order to handle the additional runoff during heavy rains, the creek next to The Castle was reconstructed with bed dimensions enlarged by 50%.

How much more additional runoff will the creek be able to handle?  Assume that the before and after creek beds are similar figures.