I am probably going against the grain here but we wash Bear often too since he is stinky & feels yucky, probably because he is so drooly, messy at eating, and exposed to all the funk of downtown. He gets washed every 2 weeks or so and loves it; so do we. Due to his extreme allergies to shampoo though, he the only shampoo that works for his skin & doesn't give him hot spots o flaky skin is Head & Shoulders Dry Scalp formula.
As for the cold water, Newfies were made for the icy water so it is fine. Bear has gone swimming in partially frozen over lakes & loved every minute of it.
On a side note, our breeder, her handler, and other show dog handlers have all told us that due to the Newfy coat being prone to such wetness, it is perfectly ok to bathe Bear as often as we'd like without hurting him or his coat.