I found some video on YouTube of County Road 1492 and the Blanco River by the 7A Resort/Pioneer Town area. The first video was filmed on Sunday, May 17, 2015 which was one week before the major flooding in Wimberley. The second was filmed on Thursday, May 28, 2015 from the same location. I also included a shot from Google Images of the same location where you can see what a "normal" day would be considered with a passable bridge. The power of rushing water is an amazing thing, and it's absolutely necessary to have proper warning systems in place to alert citizens when this sort of event occurs.
May 17, 2015 from YouTube video by Shannon Marlow du Plessis:
May 28, 2015 from YouTube video by Joanne Hall:
VIDEO: Shannon Marlow du Plessis: Blanco River Flood May 17, 2015
VIDEO: Joanne Hall: County Road 1492 at Blanco River