Food Post | 2 | Water

“Water is the driving force of all nature.”

— Leonardo da Vinci

Water. Critical to life.

Finding water on the trail is typically quite easy.  Streams, springs, spigots, and other places offer an abundance of almost clean water!

So, now you have water.  But where has it been?  Maybe a bear pooped in it upstream.  Maybe there's human waste from poor hiking practices.  There's just no way to know.  Waterborne disease on the trail is a quick way to misery and possibly ending or delaying a hike on the trail.

There are a few considerations when thinking about water filtration and what method works best:

1. Clarity/Turbidity: is there a lot of slit or particles in the water?  Is it visibly dirty?
2. Pollutants: Does the water have a funny smell?  Are there contamination sources around (roads, etc.)? 
3. Organisms: protozoa, bacteria, and viruses, oh my!

Perfect.  So now you want cleaner water.  There are a myriad of solutions when it comes to water treatment.  Water treatment falls under 4 general categories:

1. UV or Ultraviolet
   1. UV treatment can range from natural methods to using devices such as a Steri-pen.  Using the sun, while free and abundant, can require anywhere from hours to days to purify water.  Not very useful on the trail where water is constantly needed!  Steri-pens are small, pen shaped devices with a UV emitter on the end.  While decent at cleaning up water, the devices require batteries and are somewhat fragile. In addition, UV does poorly with heavily silted water and does nothing for pollutants and particles. Example: Steri-pen
2. Filters (Extensive-type)
   1. Extensive large-type filters are aimed at being harder working and more durable than those of the small-type.  While there are no distinct qualifiers between the two types, feature sets are the biggest difference between the two. Large-type filters generally contain active-carbon filters in addition to multiple other filters which remove some pollutants and improve taste.  In addition, these filters are able to process more water than smaller filters.  These filters cover clarity, pollutants, and most organisms except viruses.  The major downside of these filters is weight.  Example: Katadyn Hiker Pro
3. Filters (Lightweight-type)
   1. These filters are similar to their larger brethren, but are aimed at lightweight hiking and contain fewer features. Generally speaking, these filters contain a single filter, which excels at cleaning up clear water.  These filters work optimally with clear water which only requires microorganism removal.  Unfortunately due to their small size and single filter, these filters get easily clogged with heavily silted water and must be back flushed frequently with dirty water. Again, like their larger cousins, these filters are unable to filter viruses. Example: Sawyer Mini or Squeeze
4. Boiling
   1. Boiling is the simplest method to water disinfection.  Boiling requires nothing more than heat and time. Although boiling is free, creating heat in the backcountry requires fuel.  Boiling requires a minimum of 60 seconds, which means using critical fuel supplies, whether that is canisters, alcohol, or tabs.  Although wood is free and abundant, building fires can be time consuming and can leave permanent scarring on ground cover.  In addition, boiling requires 1 minute extra per 1,000 ft of elevation gained.  Boiling will kill microorganisms including viruses, remove some pollutants (depends on their boiling point), but won't clear up turbidity. 
5. Chemical
   1. Chemical disinfectants come in many shapes and sizes, but Chlorine Dioxide has become popular in recent years.
      1. Chlorine Dioxide: Chlorine Dioxide, is a powerful disinfectant that uses oxidation as its primary method of disinfection.  In addition, ClO2 leaves no taste.  The primary downside to ClO2 is that cold water and turbidity reduces the effectiveness of the chemical. Example: Aquamira
      2. Iodine: Old school halogen style disinfectant still widely used, but leaves a terrible aftertaste.  Still a popular choice, but maybe have gone away from it simply because of taste.  Example: Portable Aqua
      3. Chlorine: Simple chlorine bleach can be used in a pinch, but can leave bad aftertaste.  Two drops of 5% bleach can clean about a liter of water.

In the case of my hike, I will be using a combination of two methods, a small-type filter (Sawyer Squeeze) and Chlorine Dioxide (Aquamira).  I chose these two methods for two reasons.  First, the Squeeze can provide instant, nearly clean water and can be used like a straw to drink if necessary.  Second, sometimes Norovirus can appear on the trail, which the Squeeze cannot handle.  Aquamira can chemically treat and mitigate the virus.  Day to day I'll use the Squeeze, but may likely use the Aquamira when I don't want to sit around and filter water.  

There is a phenomenal article on wikipedia detailing water purification that can be found here: http://en.wikipedia.org/wiki/Portable_water_purification