Triathlon / Adventure Race / Bike Race on National Park Service Land

Anyone able to help?  I have pre registered for the "Nations Triathlon" (http://www.thenationstriathlon.com/), an Olympic Distance race planned for downtown Washington DC.  The organizing group is currently working to get the necessary permits etc, and is looking for any examples to help their case around bike / triathlon races held within National Parks.  If anyone can provide examples including the date and type of event, that would be awesome! 

If this race is able to happen, it will be pretty cool to not only participate in the first running of the event, but also to swim, bike and run around the monuments of DC. 

THANKS!

Brandon