Recently, I had a chance to visit the construction site of the new Utah Museum of Natural History. The museum sits on a beautiful, hillside location, but more impressive is the 60,000 sq ft pervious concrete parking lot.
Having a site on a hill with a 30% slope and limited space for conventional stormwater retention, the landscape architect, Design Workshop, had to incorporate LID stormwater management techniques to fit everything on the site, while still preserving half of the real estate as open space.
On my tour of the site, I'd heard rumor that the subbase to the pervious was up to 18 feet thick in some areas. However, in speaking with Project Manager Troy Cook, with Design Workshop, he set the story straight -- the subbase for the pervious is only 2-2.5 feet thick. There is, however, a large underground infiltration system on site that handles the stormwater for the rest of the site. The pervious concrete acts as a passive system, draining only itself, but overflows in heavy storm events to the underground system.
Maybe one of the best uses of technology, the website for the project shows a time lapse video of the construction on the site. If you look in the lower right hand corner, you can see the footage of the construction of some of the pervious concrete -- from the earthwork, to subbase, to construction and curing and then watch it weather its first winter. I don't want to understate how cool this video is, but would love to see it with frames from every day.