Its apparently switchback #23 according to the flicker photo description, which also refers to it as a "spring" but I won't argue about the definition, Salty. Its an intermittent "source" from snowmelt, filtered by decomposed granite (sand). That's about as pure as it gets.
Bob also filters beer through his teeth, so buy that man a cold one if you ever get the chance. The stories and wisdom will be worth far more.
