Half Dome – Yosemite Musing
. . . and not a drop to drink.” That is from the Rhyme of the Ancient Mariner by the English poet Samuel Taylor Coleridge. But on the Half Dome hike there is plenty of water – at the Merced and the Little Spring. But you cannot drink a drop without worrying about getting sick. Did you know that your mouth produces a pint and a half of water every day? Gee, maybe you just can drink that! Seriously, it’s estimated that 80% of all travel diseases are connected to contaminated drinking water. Further, The EPA says that 90% of the world’s fresh water supply is contaminated. Wow, see what 7 billion people and 1.5 billion cows can do?
In the Sierra, the main concern is with the bigger critters – Amoeobiasis, Giardia lamblia, Cryptosporidium. They tend to be in the 1 to 15 micron range. Diarrhea and intestinal issues can arise. E-coli from feces is the main culprit. There are a lot of bear, dear, mt lions, marmuts, and people tramping around the Half Dome trail. So a good filter must be able to stop them. Viruses are really small….in the order of .02 to .2 microns. But there are no documented cases of viral acquired illnesses traced to drinking water from Sierra streams or lakes. The freezing cold where the water originates is not conducive to viruses. So our main focus is in the .2 micron and greater range. Most good mechanical filter devices will protect you. Read their literature to determine the filter size.
I have been using Katadyn for eons. Pictured below is my current inventory. Their backcountry series products will indeed stop the bacteria and protozoa I might encounter. Another Christmas gift idea for you?? The one at the top is a PUR Guide. They were bought by Katadyn. I’ve had that workhorse since the ‘90’s – last century! It’s a rare virus rated filter. Sorry but the Guide has been discontinued. Click to Enlarge.
Unrelated thought worth quoting: “You do not need a parachute to skydive. You only need a parachute to skydive twice.”
*MrHalfDome – Rick Deutsch – www.HikeHalfDome.com