Harvesting Fog for water

pict

pict

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Jan 7, 2003
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Here's the deal. I'm planning a camping trip with my daughter that will take us to the top of a high ridge for two nights. The ridge has no water at the top but there are several seeps visible with binoculars from an opposite hill where we usually camp.

We will be doing this trip in July, dry/cold season for Brazil so I don't want to depend on these seeps to replenish our water supply. The ridge is always covered in cloud in the morning and I'm betting there is a healthy dew on the ground up there.

I know we could soak up water with sponges but is there a more effective way to harvest water from heavy fog? I know our tent will get covered with hevy dew and will probably yeild a half liter in iteslf. I would like to pack in a days supply of water and harvest enough to stay another day if possible. Mac
 
If I recall correctly, in Olson's book on primitive survival skills he talks about soaking up water with a handkerchief (or sponge, in your case) and licking it directly off of leaves. I would also think that you could get some accumulation with a number of sheets of very light plastic. They would have to be positioned to collect the water in the center and avoid letting it drain off the sides.

It sounds like an interesting experiment, but I'd want to test it close to home (or with backup water) before relying on dew. I did a test of the desert still/condenser design found in survival manuals (under pretty ideal conditions) and was amazed how little they yielded. I was glad I wasn't depending on the two stills I constructed. I realize that you are relying on a different collection approach, but the safety issue is similar.
 
If you're going someplace where water is scarce, it's hazardous to purposely NOT bring water. These water collecting techniques are very handy to have when you're in a life threatening survival situation, but it's not smart to intentionally place oneself in a life threatening survival situation...

Go ahead and practice the techniques, but also bring enough water with you so that your experience remains a safe and comfortable one.
 
I have used dew collection in this area and at that time of year. I was able to collect about an liter in an hour but the water was pretty brown and unapetizing.

Our plan is to pack up enough water for 24 hours. I figure on six liters total for the two of us. The fog collection or finding seeps will allow us to spend anopther day if it is successful, return if it is not. I know I can get water about 1/3 of the way down the slope in several places where it is visible in binoculars from the opposite ridge. We always camp on the lower ridge and the temptation is getting too great. Up on top of the mountains here it is a tropical alpine ecosystem. It really is different up there. Mac
 
I have read somewhere that inkas used thin nets to collect dew/fog/cloud water, apparently specificially made for the purpose, they drained directly to jars from the vertical lines. Thin plastic might be effective also, the sheet should be edge on to the wind.

TLM
 
As has been said, bring water. Then again I err on the side of caution... when 2 friends and I went to the Nevada desert for four days, we brought 42 gallons ;)

As for harvesting dew or fog, it's not primitive, but plastic tarps or trash bags are good for gathering it. They have a lot of surface area when cut and spread open. If a lot collects on leaves, you can spread out the tarp under it, shake them, then lift the tarp by the corners so the water collects in the center and can be poured into a container. Be careful not to drink bugs and seed pods!
 
I would recommend a hand-pump/filter with a bacteria guard for purifying your water. They don't add much weight to your pack and you can harvest water from some questionable sources with one.

-- Dizos
 
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