I was on the Cow on Monday and experienced the gobs of unsightly wet toilet paper coming down the river. It definetly made for an unpleasant experience and resulted in alot of down time in having to clean off your hook every cast.
Cotton Seed...NOT.
This is definitely a biological growth. If you look at the river bottom every rock is covered with this snotty fibrous grayish white toilet paper slime. Undoubtedly the cause behind this is increased nutrient loading into the river (phosphorous & nitrogen). Probably someone's septic tank is leaching into the river upstream. I hope they locate the source and put a stop to it. In the mean time the Cowlitz may come to be know as the "River of Snot."