A update for those interested....
I was camping with the family up in the area last weekend and drove past the White Salmon river at the mouth where it joins the Columbia. The dam would have been a few miles upstream. The mouth of the river was always very pretty, a deep green color. Obviously not natural but nice to look at none the less. Probably at least 30-40 feet deep under the bridge....
Those are deer in the background, out in the middle of the river. The water there would have been at least 20' deep.
Hopefully all this sediment clears out quickly and the river gets back into shape as soon as possible. Ugly to look at now, but for the best in the long run.