water calculations?- desert trip

[Mike M]

Hitting the desert (w/ a couple of forum members :)) at the end of the month and am trying to get my arms around on how much water I’m going to need to carry.

It’s going to be a roughly 60 mile, three day/two night trip.  No reliable water sources that can be counted on.  We’ll have two water stashes- at the end of day one and at the end of day two.

Roughly 20 miles/day, temps likely 70’s high, 40’s low.

I’m going to have a 20 oz bottle on my shoulder strap to drink from and need to decide what additional water to carry.  Here’s what I’ve come up with- a 20 oz bottle normally lasts roughly two hours for me in moderate temps.  I figure roughly 10+/-  hours of hiking/day- it’s a little slower than most of the hiking I’m doing, but a fair amount is off trail and a fair amount is sand (learned a valuable lesson about running in sand a few years back- it’s slower AND harder :)).  So five 20 oz bottles and will round up to six on the safe side.  Bottle is already full at the start, so an additional 100 oz- roughly 3 liters.

At camp there will be an evening meal- boil in the bag 10-16 oz depending on the meal, call it 16 oz (0.5 liters), drinking at camp in the evening- another 16 oz, maybe more?  Breakfast- hot cereal and coffee ~ 16 oz, drinking another 16 oz of water possibly before starting off.  2 more liters.

So a 20 oz bottle and 5 liters.  Is that in the ballpark?  Too high, too low?

I can also see that if we make it to the first water stash day one (and day two as well), I can eliminate supper/breakfast water on that day; but also wondering if it wouldn’t be prudent to factor in, not making it???

Obviously it would be nice to have a lighter water load vs heavy, but I don’t want to be that Montana mountain guy that dies in the desert either! :)

Any insight welcome.

[Alex H]

Dead on, at least for me.  I do a fair amount of desert hiking and over the years, unless it is really cool, I consistently use 5 liters a day.  The way I calculate is 1 liter at breakfast, 1 during the morning, 1 at lunch, 1 during the afternoon and 1 for dinner.  So very similar to your thought process.  If it is cool (below 60) then I can easily get by with 4 liters.

I will sometimes carry an extra liter for safety purposes mostly around not knowing for sure if a water source is reliable.

[Ralph Burgess]

New route including off trail?  The biggest question to me is your contingency plan if you can’t find the route or can’t find a cache, especially the second cache – where you’d be faced with either 40 miles back or 20 miles into unknown terrain?   I think you need to work out exactly what your contingency plans are in order to know how much water to carry.   If you’re paralleling a road or something that’s obviously a totally different risk profile from middle of nowhere.

That and clarifying the temperature forecast.   A high of 70 gives you plenty of margin for error.   A forecast high of 79 that turns out to be 85 is much more challenging.

[W I S N E R !]

I think your breakdown is solid Mike.  Personally, I’ll be doing 6 liters.  I expect it will be slightly high vs. actual use (temps are looking relatively mild).  I also plan on leaving a bit extra at the cache points so I can tank up before heading out again.

Good point about contingency Ralph.  In this case, I know the area.  Even if route finding becomes an issue at a certain point, locations of trails/jeep roads/paved roads are pretty straightforward to find and within safe range of XC sections.

[BlackHatGuy]

Don’t forget to take into account any need for hygiene/bathroom breaks.

I was in Joshua Tree in February, daytime temps were in the 50s I think (IIRC, which is always suspect…). I carried four liters per day, with caches near or at the end of each day, and had plenty left over at the cache each afternoon. But I tend to drink less (sometimes a lot less) water than a lot of people (I’m of the ‘drink when you’re thirsty, not on some arbitrary schedule’ school). My dinner meals also don’t take a lot of water (less than a cup usually), and I most often eat a dry breakfast, so that’s certainly part of the reason I was maybe going through 3 liters, or a bit less, per day.

I’d say make sure there’s plenty of cache water (you can always give whatever isn’t used away), especially at the first cache, so that if you undershoot your needs you’ll be able to adjust during the trip.

[David Thomas]

Mike: You’re not a small guy but (last time I saw you) in excellent shape.  As northerners in winter, we aren’t acclimatized to heat so our bodies don’t cool as efficiently as they would a week or two later.  Personally, I do okay showing in hot climes from Alaska, but like going quickly to high elevation, it’s an individual thing unrelated to other measures of physical fitness.

Your water quantities look right to me.  I’d add my 8 ounce Chrome Dome Sunbrella and subtract 1-2 pints of water.  I feel 15F cooler under it in the mid-day full sun.

I find big water bladders hard to pack in my pack.  I like my weight high and near my back so I don’t have to lean forward as much.  That’s easier to do with rigid water bottles (20-oz, 1-liter, and 2-liter soda bottles from the recycling center).

Bring an extra cap for each type of water bottle.  If you have any narrow-mouth water bottles, leave a cheap kitchen funnel at your cache (or 20% more water).

There’s some more flexibility in a group – no one will want exactly as much water as they planned on but some will be over while others are under.

If the weather is hotter than forecast, start early, take a mid-day siesta using a tent/tarp for solid shade, and hike again in the evening.

If you pee dark urine or you don’t remember when you last peed, camel-up with at least a liter and step up your intake.

[Mike M]

thanks everyone!

sounds like Craig has us covered if we screw up Doug :)

leaving a liter behind is 2.2 lbs off my back, leaving two- 4.4 lbs- fairly substantial

last time I was there it was a small miracle that Adan and I found a liter of water stashed under a juniper- probably there several years, the lid cracked when I touched it; we cut it much too close w/ water mostly due to underestimating our pace from the halfway point (both cramping badly!)

like I said, don’t want to be that dead guy from Montana who died in the desert!

[Bob Shuff]

For Boy Scouts we say 6 liters or quarts per person per day.  Some drink less and it’s always a struggle to keep the younger ones hydrated.

Having 2 caches is great, especially if you will camp relatively close to them, or at least eat dinner there.  I would have at least 4 full when leaving camp and would camel-up before that with as much as you can drink.

I’m jealous when I read about others back east or in the mountains hiking with only a liter in their pack.  Being a SoCal, normally drought-land resident I will start a desert overnight with up to 2 gallons.  Luckily the weather is often predictably dry and mild this time of year, so you can reduce in other areas.

[Mike M]

Right now I’m thinking 4 liters and my 20 oz bottle should be pretty safe w/ our water caches relatively near our campsite/supper locations.

I most often go into the mountains w/ just a liter of water, pretty spoiled :)

[BlackHatGuy]

I think you’ll be fine, especially if our caches have plenty of water. You’re not going to die (or even injure yourself really) if you happen to run out of water later in the day before we hit the cache. You might be really thirsty, but that’s about it.

I bring a non-caloric electrolyte powder that I use twice a day in my water, which probably helps me avoid any cramping even when drinking less water than most.

[Alex H]

Nunn tablets are easy to use and I do think help extend your water “mileage”.

[Steofan M]

I normally figure on 4 liters and a 16 oz Nalgene  per day in the grasslands/badlands. With your planned backups, you should be fine.

Take the Chrome Dome, the cool, breezy shade is is so much nicer that a hat can ever provide. Suck on a small rock and breath through your nose – your mouth won’t dry out and sinuses will do their job regulating water loss. Take a larger-sized kerchief to keep soaked for your neck or head and use it over your mouth and nose if it gets windy.

[Diane “Piper” Soini]

I’ve done overnights where we stayed over for 2 nights and did brush clearing during the middle day and 5 liters was enough to get by knowing that there was a chance to take a drink from the spring or creek in the last 5 miles on the way back to the car. You should be fine with your planned 5 liters per day.

[Erica R]

i carry a bit of apple cider vinegar with me. if i underestimate how much water to carry, a sip of the vinegar puts away thirst and perks me up.

[Mike M]

thanks for all the tips :)

I do use an electrolyte, learned that lesson from running ultra’s; strenuous hiking/backpacking I found requires only about a 1/4th of what I would use for running, but definitely helps.

[Steve Thompson]

My experience desert hiking at >80 degrees is ONE LITER per hour of hiking.  Damn near impossible to carry so you’ll tank up in camp and dehydrate throughout the day.  That much water and I always supplement with electrolyte (nuun tablets).  Figure what you’ll comfortably be able to consume in camp one you reach you water caches and carry the rest.

When I can’t count on water and need to carry everything I “ration” myself to 1/2 that.  By the end of a long hiking day at that ration I am headachy and overly grumpy, on top of being overly fatigued.  Still on an expected 10 hour day your 20oz + 4 liters ought to get you by as long as you can knock back ~1 liter immediately after arriving in camp and can start off with 1-1.5 liters in the tank each morning.  Carrying another liter gives you some safety margin, but as long as you have the caches at camp you can quickly recover your headache/grumpiness.  Just have enough in your caches so you can always leave some water behind.

[Mike M]

^ good point; we definitely don’t want to be stingy with our caches- I’m figuring leaving three gallons at each cache, enough to drink some there, enough to cook supper and breakfast, enough to drink while at camp and a full 4 liters and 20 oz bottle heading out of camp

[DuncanA]

Death Valley at Christmas per day for two people: 1L breakfast, 4L during the day, 3L in the evening (we’re British and like 2 cups of tea :) ) = 8L/2people/day i.e. 4Lpppd.

It was cool. We did have pre-planned bail-out options for the off-trail sections which would get us either to our car or a road in <1 day.

[Miner]

I do a lot of hiking in the SoCal deserts, Fall through Spring. With the temperatures you describe, I’d put out a gallon each day, but I don’t normally cook when hiking in desert like conditions, so I don’t need water to rehydrate my meals. It would be purely for drinking. If it was going to be in the 90’s or higher, I’d put out more, or take a long siesta in any partial or full shade you can find during the heat of the day and start getting up before dawn each day and hiking later into the evening to compensate for the lost time. Instead of fighting the heat, just hike when it isn’t so hot and you won’t need as much water.

[Terry Sparks]

With thru-hiking Death Valley, Death Valley to J-Tree and the 750 miles of the CDT through NM and WY deserts and other hikes, I’ve found that wearing a hat cuts your water consumption by 5O%. I also recommend buying a Sham-Wow! From eBay or elsewhere to keep wet under your hat, it works.   For water caches, use cardboard 1/2 gallon milk containers buried for your water, mark your cache with a waypoint and flagging tape. Once you retrieve your cache and transfer the water to your carried containers, rip up the milk cartons put them in the hole you dug, burn them and cover the hole, nothing to hike out and no need to worry about starting a wild fire, if you’re in sparse vegetation.

I find that for me a gallon per day is the minimum and since you have the cache already, its only smart to have more.  I’ve also found that. buried food, even in the desert, stays cool.  Think about adding ziplocked un-canned peaches and the like to the cache. Put your food in quart freezer zip locks and then into a large Nylofume bag, which is buried with rocks covering the site.

[Mike M]

^ good tips- thanks :)

we ended caching 2 gallons/person and had water left over- which is certainly better than the alternative!

[Author]

Posts