Effects of rain on backcountry water source

[bikehikeskifish]

What effects will all the rain have on the backcountry water sources? I suspect the bacteria counts will be up, and other nasties too, as whatever has been multiplying will get washed down to the streams. Presumably a pump+filter is still a safe method?

Tim

 

[DougPaul]

What effects will all the rain have on the backcountry water sources?

There will be lots of water...

I suspect the bacteria counts will be up, and other nasties too, as whatever has been multiplying will get washed down to the streams.

That would certainly be the case if heavy rains followed a dry spell. However, given that it has been one sustained "flush", it might not be so bad.

Presumably a pump+filter is still a safe method?

Of course*. Same nasties as usual.

* This gets everything except chemicals and viruses. Neither are an issue in the NE mountains.

Doug

 

[DrewKnight]

Heavy rains definitely raise the bacteria counts... in Waterville Valley, it was so bad a couple Octobers back that we ended up with bacteria issues in the town wells, and were on a "boil water" order for a long weekend. The town beach typically closes after periods of heavy rain -- and it's entirely stream-fed.

The usual precautions (filtering or other treatment) are even more important -- but should work just fine.

 

[MadRiver]

I’ve been following a few thru-hikers journals and several have contracted giardiasis as they passed through the Whites.

 

[Dr. Dasypodidae]

I’ve been following a few thru-hikers journals and several have contracted giardiasis as they passed through the Whites.

If the thru-hikers were not treating their drinking water the whole way, I am surprised that they did not get sick a lot sooner, long before they reached the Whites. I know a lot of hikers who still drink untreated stream flow in the Whites, but they probably have cast-iron GI tracts as they never seem to get sick. I, on the other hand, got so sick with Giardiasis from untreated water about three decades ago that I have treated all of my drinking water ever since.

 

[Lawn Sale]

A filter and disinfectant is always safe, unless your filter is so old it's the cause. A filter alone is not enough.

Today's filters cannot have breakthrough due to their design, if they get clogged, they just stop pumping. It doesn't matter if you're pumping from a mud puddle or clear stream, the only difference is how often the filter element must be cleaned or replaced.

Yes, the bacteria counts go up, but there is typically no flushing action because when the increased volume subsides, the levels go back to normal.

 

[bikehikeskifish]

A filter and disinfectant is always safe, unless your filter is so old it's the cause. A filter alone is not enough.

Are you saying this in the general case, or specifically because of high water? I only ever use just a filter and it sounds like levels go up, but no additional risks are suddenly present.

Tim

 

[DrewKnight]

I think that's the right way to think of it, Tim. Filters don't care if there is a sudden influx of nasty stuff... if your filter is designed for backcountry use, it should be fine for any conditions. I would guess the only real issue is that all the run-off also raised turbidity, so you have more schmutz in the water to filter out (and that can shorten the life of your filter... if you have time, let the source water settle out first).

About half a lifetime ago Nancy (MrsDrewKnight) and I spent a year in Asia with a first-generation FirstNeed filter. It was a daily chore to pump a couple litres of water, wherever we were, every morning to support drinking, tooth-brushing, etc. We drank water in some very dubious places and never had an issue (though we did have a few food-borne lower-GI parties). The only thing we ever encountered that the filter just couldn't deal with was "glacial flour" from the Everest valley... glacial till ground so fine and suspended in the water, the filter didn't take it out, and it wouldn't participate over the course of a day. The nurse we were with at the time said it was not an issue, though, and we survived unscathed.

 

[Lawn Sale]

Are you saying this in the general case, or specifically because of high water? I only ever use just a filter and it sounds like levels go up, but no additional risks are suddenly present.

Tim

Just using a filter misses some of the contaminants, unless you're using a First Need Purifier. Specifically these are some of the bacteria and all of the viruses, which are too small to be caught by the filter, so an external disinfectant (like chlorine, chlorine dioxide, iodine, etc) is needed for complete inactivation (destruction) to make the water safe.

Once water has been filtered, even a drop of regular household chlorine bleach will do the job for a Nalgene. I recommend people add two drops, just in case the water is cold, pH high, etc.

I never push the issue though, people are always free to drink organic if they want.