The sand was coated with mud having been the bottom of the river for so long, so it stuck to her belly and legs and then the sand stuck to that. Before long she had dreadlocks! So funny. She couldn't work it out, kept looking at her tummy and legs and in the end, gave up and just enjoyed running around and around in it.
I simply gave her legs a quick hose down when we got home, then allowed her to dry off and brushed the rest out....no more dreadlocks! One very happy and tired 10 month old puppy. Ate well and slept well that night.
I took a small video of her as well, if you want to see that it's on my Facebook page.