We had a big rain on October 10, 2006, so when leaving the house we went by Walnut Creek where it splits Sandy Harbor. The only access to the west side of Sandy Harbor is across this low water bridge, which is normally dry. Here it's about 2 1/2 feet deep on the depth gauge, so there were a few hours when you couldn't cross.
Here's a short video of Walnut Creek 2 1/2 feet over the crossing. You may have to click the play button twice.
We went down to the Sandy Harbor boat ramp on Sandy Creek to see how much debris was going down the creek, and spied this Blue Heron about to fly across the creek
Here's another video of the Blue Heron on Nov 19, 2006 when Sandy Creek was back to normal.
Lake LBJ has several tributaries, the Llano and Colorado rivers and several creeks. Sandy Creek and Walnut Creek on the south side of the lake usually flow very little. But occasionally we get a hard rain like on October 10, 2006 and the rain can't soak in as fast as it's coming down. The Sandy Creek bed is usually a wide flat area of sand, mainly full of cattle hoof prints. This picture was taken that day on our way from Sandy Harbor to Kingsland at the Hwy. 71 bridge. Sandy rose about 9 feet that day, not the highest I've seen it by far, but the highest in over a year if I remember correctly.
On the way back from Kingsland about 2 hours later we stopped again, you can see the creek has risen almost enough to cover that island in the middle. The Sandy Creek watershed goes all the way to Enchanted Rock, so it can rise to 20,000 cubic feet per second or more.