I think the state has a lot to learn about dealing with excess water. Thanks Amanda for the comments and the link. Eco Tecture There are so many different ways to capture and use excess runoff as your site talks about. The Landscape Architecture magazine a couple of issues ago had a great article highlighting Portland's street solutions by Kevin Robert Perry, ASLA.
I have only lived in Central Oklahoma for about 6 years. However, it is not uncommon to get a deluge of rain that runs up over the top of the curbs. I know that it is the smaller and more regular rainstorm that creates the bulk of the runoff.
Brent sent me the Oklahoma Mesonet link that gives the actual monthly extremes. Oklahoma has some reasons for paying closer attention to water run off.