How much water?

[ErichFromm]

I'm sure there must already be a thread on this but couldn't find one....

I've recently realised I carry too much water when hiking (I'm the same with petrol - always go to fill up as soon as the tank drops below half). But my knees are increasingly becoming an issue and it's made me pause to consider how much water I take each hike.

As an example, on a recent walk (Macallister Springs to Mt Speculation, down into valley and then up Zeta track) I took a good 7 litres of water. And yes, I know there is water at the Mt Speculation car park. This is a lot of water to carry and clearly I need to reduce it - but the question is to how much? And yes - next I'll ask how long a piece of string is... On the other side of the equation I ran into some other hikers on top of Mt Buggery who ran out of water (I gave them a litre) - and saw them again atop Mt Speculation as they were desperately trying to locate the spring there to get some.

So where do you find the balance of having a bit of a buffer in case of emergencies and taking so much you are a walking water dispenser? It becomes even more difficult when you are not familiar with the route - how can you be sure you'll find the water source others talk about?

[GPSGuided]

What's your fear in not having carried enough? Absence of water source? Quality of water found? Fear of drinking water in the wild?

[ErichFromm]

Not fussed about quality or anything like that (carry puritabs). More absence of water source....don't want to get stuck 2 days out from my car with only a few ml of water left....

[Empty]

I hate carrying water so if there is water to be found on route then that is what I'll be drinking. Recently bought a Sawyer Mini and it is a game changer - simple, effective, fast, light and cheap.

The problem I have had of late in central Vic is that we have not had decent rain for a good six months ormore. Had a little last week but still not enough to create reliable surface water. That being the case I have only being carrying food that does not require water to cook or reconstitute and, try as I may I can never get by on less than 3 litres per day. So that is 6 kilos I cannot avoid carrying.

[GPSGuided]

Ration, reduce usage (waste). What's been your daily consumption?

[ErichFromm]

Depends on temp and how much I'm exerting myself etc of course: can range from practically nothing to 3 litres in a day....which is why I carry so much "just in case"...

An American site I looked up recommended 2 litres a day - but they can find water all over the place so quite a different scenario....

[nq111]

I feel your pain.

Up here, I do overnighters up here on mountains with no water up or down. I take 10-12 litres - and can be pretty dry by the time I get back to the car. You can only absorb 700-1000 ml an hour, but can sweat more than this when really working hard and it is hot.

In Tassie I reckon 2-3 litres per day (excluding camp) is what I use, but because I rarely need to carry much (so many water sources) I don't really track what I drink.

Having once run out of water at the top of a mountain when I was younger, and then having to spend the night and all the next day coming down without a drink, I am pretty paranoid about running out of water too. Not a good feeling.

[GPSGuided]

Sounds like you are a bit stuck unless you can cut the consumption. Or cut down to shorter walks or walks that have known water supply.

[ErichFromm]

10-12 litres?!! How much does your pack weigh? Damn - you must be skipping on the way back once it's all gone...

One obvious thing that I did to reduce consumption was to only use a bladder and force myself to sip - after gasping from a particularly bad uphill section the temptation is to gulp the water down... I even use gastrolyte tabs to help get maximum bang for my buck...

[cajun]

You can only absorb 700-1000 ml an hour

Hi NQ,

That is an interesting fact. Do yo know if there are factors that affect the absorption rate?

Cheers,
Ken

[nq111]

10-12 litres?!! How much does your pack weigh? Damn - you must be skipping on the way back once it's all gone...

To answer your question - too much! The only good thing is the tropical gear list is pretty light. But my starting weights for an overnighter up here and a 7 day walk in Tassie are about the same. End weights are much less for the tropics however.

One obvious thing that I did to reduce consumption was to only use a bladder and force myself to sip - after gasping from a particularly bad uphill section the temptation is to gulp the water down... I even use gastrolyte tabs to help get maximum bang for my buck...

I believe the current guidelines are there is no benefit to rationing water. However you don't want to force yourself to drink more than you can absorb.

[Moondog55]

For myself 3 to 5 litres a day unless it's really hot in which case it can double depending on my work load, but I sweat a lot.
About 1 litre of that is for cooking and about 200ml for hygiene the rest is drinking water

[nq111]

Hi NQ,

That is an interesting fact. Do yo know if there are factors that affect the absorption rate?

Cheers,
Ken

Not with any qualification. There is a fair bit of information about on the net - i found this site very useful but haven't read through it in a while http://www.badwater.com/training/index.html. Some marketing fluff but also obsessive, highly qualified writers (e.g. general physicians who like to run marathons). I would expect normal variation in people plus conditioning to exercise and hydration would be significant?

Certainly you have to work pretty hard to sweat more than a litre an hour but it is possible (a maximum recorded figure of about 2.5l/hr sticks in my memory?). Indeed, there are some interesting scientific articles about on how humans are supremely adapted to deal with exercise in hot conditions - something that goes back to a concept we may have evolved to chase down game through sheer stamina in hot African savannah country - like some bushmen still do today. However it is clear humans need to adapt to exercising in heat - going straight from Tassie to NQ in summer is a killer - you feel weak just walking to the shops.

[walkon]

I feel your pain.

Up here, I do overnighters up here on mountains with no water up or down. I take 10-12 litres - and can be pretty dry by the time I get back to the car.

I reckon that I would drink half of that just carrying all that weight around

[Moondog55]

When we were running in summer in The Alice it was normal practice to weigh ourselves before and after our usual run [ 10 to 12k / 2 Hrs ] and quite normal to be 3 or 4 kilos lighter at the end.
I can remember running home from work one warm summers day and going into the shop at the end of my street to buy vegies for dinner and after 10 minute be standing in a pool of unevaporated sweat that had run down my body and pooled on the concrete floor, I am super heat adapted after 30+ years in commercial kitchens and I easilly sweat 2 or more litres an hour in hot conditions

[GPSGuided]

Bottom line, you need as much water as you need for the condition. If it's too much to carry, then better cut down on the walk. No alternative. Otherwise, learn to save as much as possible and replenish when possible. Trial and error is the only way to go at an individual level.

[perfectlydark]

I wince at having to bring 3l for an overnight (no water for cooking and on a good walk ill find a source at some point to replenish). If the water source was garunteed I would go to 2l

[stry]

My walking is almost entirely in the cooler months in Victoria, and from time to time in Tas and NZ.

I know I can get through a camp (one evening meal and one breakfast) comfortably on 2.5/2.75 litres. If I know camp will be dry, that's what I carry for camp.

Daily drinking intake while walking is an additional .5 to .75 litres per day. I am not a heavy sweater. Wherever possible all I carry is .25 to .5 as a whistle wetter.

In the conditions described above, I have never carried more than 3.5litres total. I am quite happy to use, with appropriate care, water from natural sources. All these figure were arrived at by personal trial and error as GPS has recommended.

My experience in hotter places is limited, but Feb in northern Qld a couple of years ago is the first time I have ever wished I had a hydration (hate that word) bladder. I didn't check, but daily consumption while walking was at least two to three litres a day. Camp consumption was higher also, but only because of more (water) drinking.

[clarence]

I rode a bicycle around Australia some years ago. There are a few stretches in the NW and Nullarbour where it is nearly 300km between water. This equates to 2 to 3 days of riding. I got very good a calculating exactly how much water would be needed.

Even in hot conditions (30-38 degrees C), and riding 120km (6hr) per day, with enough for drinking, cooking and a very basic wash/wipe up each night, 8L per day was spot on every time. So, for a two and half days of riding and two nights of camping I'd carry 20 litres (easier on a bike than in a backpack). This assumes one is aclimatised to activity in those conditions.

A very important part of water usage is controlling how much is sweated out. For the above scenarios I'd sit under a tree (or in a culvert under the road) from midday until 4pm, as this was the hottest part of the day, when rates of sweat would be at their highest. By doing the heavy exertion in the cooler parts of the day makes a very substantial difference.

As noted by others, the body can only absorb about 1L per hour, and can sweat in excess of 2L per hour.

For general walking in more mild climates (Blue Mtns, Tas, Snowy Mtns) 3 to 5 litres per day (drinking, cooking, washing properly at camp) would be my typical water usage.

In 20+ years of walking I've only genuinely ran out of water once. We managed to survive on a 700mL bottle for the night (no cooking or breakfast) and found water in an hour the next morning.

Clarence

[andrewa]

Wow, what a topic....

Most humans at normal activity require about 2l per day. Water is lost through urine, faeces , sweat, and to a degree exhalation, the latter of which is prob minimal. A hot day, you'll lose 2-3 l, maybe more, in sweat.

My backcountry trips are largely limited to ski touring on Bogong, and occasional trips like the Razorback/Crosscut saw etc, and mostly with 2-3 people. Personally I'd aim for 2l per day per person on Bogong in winter (knowing that I can melt snow if needed ), and 3-4 l per day per person for areas without obvious water supply, which also allows a "just in case" scenario. This is for drinking/cooking/washing up.

Fortunately most of my trips these days are related to ski touring or fly fishing, so I have some source of water available readily!

a

[Moondog55]

Andrew I think that part of the problem here is that most "Normal" activity is sedentary or only marginally active and in controlled environments.
Certainly most normal people don't run on days of 37 to 40C and obviously my answers were at the extreme end of need, but the weather can change and if you know that in hot weather you may need more water then it is only prudent to make allowances [ that's why there is always ~ 20l in the back of the ute for example]

[wayno]

low humidity can add real issues to water consumption, you loose water faster through your skin in low humidity, you dont realise how much because the sweat evaporates so fast. so the body sweats as much as it can in the heat to keep trying to loose heat through evaporation, just the simple difference in moisture content between your body and the air means the moisture is literally also being sucked out of you because the air has so much ability to absorb moisture in warm conditions...
high humidity also has issues because the sweat doesnt evaporate well so your body again pours out sweat when its warm to try and cool itself.... and theres why you end up needing so much water... people adapted to the heat can sweat up to twice as much as those unadapted to it.

[GPSGuided]

The build up of crusting salt on your skin will give you an indication.

[nq111]

The build up of crusting salt on your skin will give you an indication.

Yeah, though one of the outcomes of heat adaptation is you greatly reduce the sweating of salts.

[Ellobuddha]

A little off specific topic i know but i find that chewing gum really cuts down my thirst whilst walking. I normally will drink a lot before setting out for several hours before and a good top up before I actually leave. I've found that really helps.

Sure I know that you still need to rehydrate once at camp but Ive found I'm only carrying about half what I used to need for actually walking.

[ErichFromm]

A little off specific topic i know but i find that chewing gum really cuts down my thirst whilst walking. I normally will drink a lot before setting out for several hours before and a good top up before I actually leave. I've found that really helps.

Sure I know that you still need to rehydrate once at camp but Ive found I'm only carrying about half what I used to need for actually walking.

Probably a very similar concept as that old desert trick of sucking on a stone (or at least according to the Biggles books I used to read as a kid)... Both the gum and stone make you produce saliva which takes the edge off your thirst...

[icefest]

I really hate carrying water and will often pick routes that enable this laziness of mine. I'd rather carry a good topo with which I can plan water points than have to carry water. 

[GPSGuided]

I really hate carrying water and will often pick routes that enable this laziness of mine. I'd rather carry a good topo with which I can plan water points than have to carry water. 

You would have been a good early day explorer if you were born 200 years earlier!

[Tortoise]

A little off specific topic i know but i find that chewing gum really cuts down my thirst whilst walking. I normally will drink a lot before setting out for several hours before and a good top up before I actually leave. I've found that really helps.

Sure I know that you still need to rehydrate once at camp but Ive found I'm only carrying about half what I used to need for actually walking.

Probably a very similar concept as that old desert trick of sucking on a stone (or at least according to the Biggles books I used to read as a kid)... Both the gum and stone make you produce saliva which takes the edge off your thirst...

Interesting topic! +1 for the hydrating well before I leave - same after a fill-up on route.

A big difference I've found has been since doing a Buteyko course - retraining breathing for improvement in a wide range of illnesses, due to increased oxygenation of the tissues through higher CO2 in the blood (the Bohr effect). Something in it, as I've never needed my ventolin in the 4 or so yrs since. I often needed it in the past when I started up a mountain - cold air and exercise and all that.

ANYHOO, it involves shallower breathing, always through the nose. If i need to suck in air through my mouth, I need to slow my pace till I can manage. A nice side effect is marked reduction in water loss through respiration, so I don't need to drink nearly as much as I used to. Also, nose breathing means my mouth stays more moist, so I'm not wanting to drink all the time.

I had an interesting walk through part of the AAWT including the Dry Barries etc in a dry year in the 1980s, where we had to severely ration water, despite carrying 6litres each whenever we could find it. We were pretty dehydrated considering the small urine outputs. Weren't far off going into survival mode, but we managed. Licked a lot of dew off leaves in the early mornings.

I would now NEVER drink my last drop EVER unless I was dying - amazing how long a mouthful of water can be made to last, and there is a huge psychological bonus in having a choice re drinking now or later.

It's taken me decades to get used to carrying less - now in Tassie I sometimes walk with people who only carry a cup! So it all depends. I'm all for 'Can anybody tell me what the flow is like at Mac Springs this week?' kind of question on this forum. Why carry 6 litres if 1 or 2 will do?!

Depends on temp and how much I'm exerting myself etc of course: can range from practically nothing to 3 litres in a day....which is why I carry so much "just in case"...

An American site I looked up recommended 2 litres a day - but they can find water all over the place so quite a different scenario....

So many variables, so different between people. I'd take a closer look at what variables are relevant when you do need the 3 litres/day, and when you don't. If I carry less, and find 'oh no, it's way hotter than I expected', I ration it in the first half of the day, knowing I can fill up later. But then I'm not walking in the desert.

[GPSGuided]

It's amazing to think how the early explorers prepared for their expeditions across the deserts? What's their basic water calculations? 1L/day?