Fast, full and brown

Many places in the area have received this months average rainfall in less than a week The river is flowing very quickly and carrying a lot of silt which will eventually fall out.
In some ways it reminds me of a very old Isle of Wight riddle.
What is brown and comes steaming and slip slopping out of Cow(e)s.
Answer : Paddle steamers. 
Told to me as a child very many years ago.