How can I obtain drinking water in a saline area such as the Northern Great Plains?

Question

If the topographic map is to be believed, there are plenty of streams in Grasslands National Park, but apparently they are saline. Last and Ginn report that there is no other area in the world that can match the concentration and diversity of saline lake environments exhibited in the prairie region of Canada and northern United States and saline springs are common in the Pasquia Hills region of east-central Saskatchewan, in southern and southeastern Alberta, in the Turtle Mountain area of southern Manitoba, and in the Lake Winnipegosis area of west-central Manitoba. The Grasslands National Park websites notes that, in both East and West block:

All surface water in the area is unfit for human consumption. Treating water by boiling, filtering or adding iodine may remove some bacteria, but will not help with the salinity.

Is there any practical way to treat this water still? We already have a Ultra-Violet (UV)-based water filter and a particle pre-filter, but that will indeed not help with salinity. Realistically, can I treat surface water in the Northern Great Plains in a way to make it fit for human consumption? The Katadyn Survivor claims to be the smallest hand-operated emergency desalinator in the world. It sells for €995 and masses 1.13 kg. €995 is out of budget for our water treatment, and I'm not sure if a device intended for emergency use at sea is suitable for operational use on land. Short of carrying all water for the entire hike, are there any other approaches that we can use to make surface water in Grasslands National Park drinkable?

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Last, WM., Ginn, F.M., Saline systems of the Great Plains of western Canada: an overview of the limnogeology and paleolimnology. Aquat. Biosyst. 1, 10 (2005). https://doi.org/10.1186/1746-1448-1-10

Answer 1

I've been to the Northwestern part near Val Marie in April 2004.

Carry a Supply of Water

... probably the only realistic option.

Val Marie drinks reverse osmosis water and I took the advice of the rangers and took a supply of such reverse-osmosis water with me. I took a large supply in the car, making sure to start well hydrated in general: a generous drink right before leaving the car plus a realistically large supply on my hike - April isn't that hot out there, but the generally dry air together with the wind means that one does need more drinking water than, say, hiking Vancouver Island in the fog.

The water in Val Marie that is not intended for drinking is not de-salted. It doesn't taste good (I tried), but it can be used directly e.g. for showering and it will not leave you with a salt crust like say, swimming in the Mediterranean and then letting yourself dry.

Rain water

I have a strong suspicion that the topographic map should show most of the little creeks (probably pretty much everything but Frenchman river) as seasonal creeks. At least, I didn't even find puddles in the side coulees where I was (but then that region doesn't get that much snow - I know the preceding winter had uncommonly large amounts of snow in Winnipeg, but I don't know whether that snow extended so far west).
The soil is basically gravel with hardly any topsoil: coulees form easily due to water/wind (and nowadays foot) erosion, but water will drain practically immediately.

Environment Canada has historical weather data for Val Marie.
Over the last 22 years, the chance to hit a day with > 3mm precipitation was >10% for end of April - August/September, with the maximum approaching 20 % in early June (7 day x 22 year averages). But that's still only 1 out of 5 - 6 days in June and you'd probably need to keep in mind that thunderstorms are not necessarily very good for collecting water via tarp. And it is also hard to plan collecting thunderstorm water, because the precipitation tends to be local.

Possibly with the exception of right after a thunderstorm, even if there's water in the small creeks, it will have gone through the salty soil. IIRC I was told that Frenchman river isn't that salty (because it carries water from the Rockies), and that freshwater crabs live there though they have a muddy taste.

However, when I was there, there were still some of the dams of the former farms intact. These dams were built to collect rain water for the farm use (human + cattle) and contain fresh water. Whether they are still functional 15 years later, and how they look after the reintroduction of bison I have no idea. But back then they were marked in the map (like each single tree) that was available at the ranger station in Val Marie. Some had a tree and were thus easy to find, and at least towards the end of April they were looking fine in terms of water supply (I didn't try though, because I brought sufficient water and did not bring a water filter).

Further considerations:

• When I was there, the park was just under construction (if you want to call it construction) and it was anyways out of season, so everything was very relaxed (I don't know whether there was any other visitor while I was there). I can well imagine that even if the dams are still functional, park regulations may ask you to not touch that water unless in an emergency.

• Idea: if you plan to cook pasta, boiling in the salty water may be OK (or not - depending on what salts there are; in particular Mg²⁺ and SO4²⁻ both bind large amounts of water and cause diarrhea if not vomiting - so taste a drop first).

Answer 2

Distill by fuel (doesn't work well on the go)

Technically you could distill the water, but this takes a long time and uses a lot of fuel. I'm not sure how many ounces of water you can distil with an ounce of some fuel, but I am willing to bet the conversion rate would be too terrible to be practical. And even if you used scavenged wood, you would have to clear enough wood from the area that your impact on the location would be very noticeable.

Adapt emergency survival ideas

What you could do is look at emergency survival information for procuring drinking water at ocean, and similar information for getting water in a desert, and see if you are willing to do anything similar to those.

A lot of "water in desert" guides talk about solar stills where you set something up to collect water condensing on a tarp or plastic sheet. This does not work well for a hike, but you have several thing in your favor: you have a lot of water unlike the desert solar still, and you are planning ahead on carrying gear for this so you can use better resources.

Solar distilling portable devices

I have a solar oven that weighs 2 pounds, as much as 1 liter of water. I haven't tested to see how fast it can evaporate water (I really should), but as long as it can provide more than a liter over your trip it's worth carrying 1 liter less and taking this instead. And as an added bonus it cooks food too!

If you don't care about using it for cooking, you can buy or make a device specifically just for solar-distilling water. The first device I looked into on amazon is no longer available (it had bad reviews about how fragile it was), but it said it was 2 pounds and could distill between a ping to a half gallon per day. One review reported a pint per day, another reported getting a liter per day, so they back up the item's claim. Since the 2 pound item was still too fragile for repeated use, a good reliable one might be prohibitively heavy if you are hiking solo.

Rain

Most people plan ahead to avoid the rain when they go for a hike. However, if you are properly prepared the rain is usually not so bad. If you planned ahead specifically to go when you expect rain, you could bring resources for catching the rain.

If I just worked the math out right in my head, I think a tarp that is at least 10ft by 10ft should be able to collect a gallon of water with less than a millimeter of rain. You should both double-check my math and practice this if you wanted to attempt it on a hike.

Take time out for supply runs (they can still be naturally sourced)

@cbeleites comments:

Wrt safe distance to water, at least in the Northwestern section of the NP, I don't think any point is further than maybe 8 km from the Frenchman river.

This is an excellent point. Since you're hiking you have access to more options than to simply heading back to the trailhead.

You could chart the distance to all the nearest sources of freshwater and make periodic side-trips to them as needed. It shouldn't take too long to make an 8km detour every 2-4 days.

Or you could even plan your hiking path to intersect these water sources every few days. You would just need to plan a hike ahead of time that snakes around a bit more, but that might be fun.

This is another good "take lots vs get out" compromise. You still need to plan ahead and gather extra water, but not for the entire trip.

Safety

If you choose to rely partially on water acquired on the hike, just remember to always make sure you have enough water to last long enough that you can get to a safe location. If you don't have enough water to return to a safe place, don't go any further.

This means you might have to change your plans if you can't acquire enough water while out.

Be careful of considering natural freshwater sources as one of these safe places to return to: some water sources aren't available year-round, and you wouldn't want to retreat to one to find it dried up and die of dehydration.

Reverse Osmosis

I think there are reverse osmosis devices that are portable. I looked into it a long time ago. I think I came to the conclusion that it was not worth it, similar to your $1000 find.

If you want to see if that answer has changed in recent years you can try to do a search for something like "portable reverse osmosis". I won't bother to do that search and produce the result here, as specific price fluctuations and their current values are off topic in general.

Summary

I suppose what I'm getting at is that you should not look at trying to acquire all your water out, and you don't have to haul it all either. For an extended duration you can bring some and try to acquire some. And have a plan B short trip in case acquiring doesn't work as well as you'd hoped.

Whatever you use, you would likely need to practice it some before heading deep into a hike relying on it.

Just remember that for acquiring water out to work well, the methods of procuring water that you carry have to be lighter than the total amount of water they can provide over the entire duration of the trip, otherwise you might as well have just carried it all.