The Southern Alps are wet. Water is rarely the limiting factor on a tahr hunt the way it is in the American West or in southern Africa. But "rarely" is not "never," and the wrong assumption can dehydrate a hunter in twenty-four hours.
How much you need.
A reasonable working figure is 3 to 6 litres per day. The bottom of the range is for an easy day in cool weather sitting on a glassing knob. The top is for a long stalk in the sun on a southern face in May. Add a litre if you are sleeping at altitude — you lose more water through respiration than you expect in dry alpine air.
Where it comes from.
In most tahr country there is a stream or a tarn within a few hundred metres of camp. The big braided rivers in the lower valleys are reliable. In the high basins, snowmelt and small spring-fed creeks are everywhere.
The exceptions matter. Ridge camps without running water below them require water to be carried up. Some glassing positions are an hour's walk from the nearest reliable source. In a dry autumn, eastern catchments — the Rangitata head, the Godley, the Macaulay — can have surprisingly little flowing water at high elevation.
A simple habit: when you find good water, drink some, top up, and only then carry on. Don't walk past water with empty bottles.
Quality.
NZ alpine water is generally clean by global standards. Snow melt and fast-running streams in the upper catchments are typically safe. But "safe" assumes no sheep, no hut downstream, no dead animal in the source basin, and no upstream camp. None of these can be confirmed at a glance.
The default for a tahr hunter is to treat all drinking water. The methods, in order of common use:
Chlorine dioxide tablets (Aquatabs, MicroPur). Light, cheap, reliable, kill viruses and bacteria. Effective against giardia in 30–60 minutes; against cryptosporidium in four hours. Bring twice as many tablets as you think you need.
Hollow-fibre filter (Sawyer Squeeze, Katadyn BeFree). Fast, no chemical taste, removes bacteria and protozoa. Cheap. Will not remove viruses (rarely an issue in NZ alpine water) and will fail if frozen — keep them in your jacket pocket on cold nights.
Gravity filter (Platypus GravityWorks and similar). Slower setup but excellent at camp for a multi-litre fill while you cook.
UV pen (SteriPEN). Effective and tasteless but adds batteries and complexity. Less popular in alpine work than tablets or fibre filters.
Boiling. Always works. One minute at a rolling boil is sufficient. Costs fuel.
The right answer for most tahr hunters is a Sawyer Squeeze on the body for in-the-day refills and a small pack of Aquatabs as a frozen-filter backup.
Carriage.
A single 3-litre bladder sounds great until it freezes overnight. A 1.5 to 2-litre bottle paired with a 1-litre flexible flask is more flexible: bottle on body for cold nights, flask in pack for daytime. Tritan or HDPE bottles tolerate the cold; bladders' drink-tubes freeze first.
In genuinely cold conditions (sub-zero nights, sub-five daytimes) carry the bottle inside your jacket between drinks. Keep the cap loose on the way down so you can sip without taking off gloves.
Snow as water.
Snow can become water but at substantial fuel cost. A litre of melted snow takes four times the fuel of warming a litre from a stream. As a rule, walk the half kilometre to running water rather than melting snow at camp. The exception is a high storm camp where running water is genuinely inaccessible — in which case carry an extra canister of fuel and plan to spend forty minutes a day melting.
Hydration as a hunting tactic.
Subtle dehydration is the most common reason a fit hunter runs out of legs on day three. The first signs — minor headache, thicker urine, slight irritability — are easy to miss in the cold. By the time you feel thirsty you are already a litre and a half down.
A few habits that work:
- Drink half a litre when you wake up, before anything else.
- Drink with every snack break on the hill.
- Drink a full half-litre on arrival back at camp, before you take off your boots.
- Watch the colour of your morning urine. Pale straw is the target. Dark amber is a problem.
- If the day has been hard or salty, add an electrolyte tab to one bottle in the morning and one in the evening.
Last note.
Boil all camp water that will be used for cooking dehydrated meals or hot drinks anyway. Reserve filtered or treated water for your bottles. Do not drink from any water source within 200 metres of a camp, including your own from yesterday. Be the person upstream.