During the winter, Lake Tapps is Drained by a couple feet, exposing a good bit of clay-like mud with some sand that is a lot like tidal mud, it was about knee deep and had some solid material and rocks at the bottom, this spot is found here: 47°14'17"N 122°09'38"W, there’s also a floating grass-bog mat here: 47°14'19"N 122°09'40"W