In a normal temperate environment a person requires 3-5 litres a day, increasing with temperature and levels of exertions. If not enough water is consumed dehydration will set in. Symptoms include thirst, headaches, dizziness, tingling in the limbs, reduced saliva and urine output and dark urine. At best dehydration will result in reduced concentration, at worst death. Tip, remember coffee and tea (not as bad) are diuretics so can not be considered as part of your fluid intake, when you have a chance to refill your water bottles take this opportunity to drink as much as possible, better in than out. A good list of water don’ts is given by Hildreth, a summarised list is given below:
The easiest means of collecting water are from rivers, lakes and ponds as shown in figure 3.1.0. Rivers are normally best, as the chance of contaminates accumulating are reduced. Tip, obvious signs of pollution include foaming, oil, areas of dead vegetation and dead fish. If possible collect clear, fast, free following water, upstream of any animal activity or human habitation, as shown in figure 3.1.0.1. Another good water source is rain water and snow. Apart from heavily industrialized areas, contamination from water passing through the atmosphere is minimal. The main source of contamination comes from the surface used to collect the water. Effective rain traps can be made from a tarp angled to fill a suitable container. Remember contaminated water may not have any warning odour or flavour, if in doubt boil. Other techniques I haven’t needed at this time include:
Figure 3.1.0 : Water sources : Ponds
Figure 3.1.0.1 : Water sources : Streams
Figure 3.1.0.2 : A simple well
Figure 3.1.0.3 : Ground water seepage from the base of a cliff
Drinking untreated water at best may result in diarrhoea, at worst serious illness or death. The main source of containments are:
The standard method of purifying water is boiling. First filter the water through a Millbank bag to remove any suspended particles (figure 3.1.1). This is to avoid the burnt banger affect i.e. when barbequing sausages its easy to burn the outside whilst the inside is still raw. The same is true for suspended particles in the water, which protect any viruses and bacteria within from the external heat. When using a Millbank filter ensure the bag is well soaked before filling it to the top with water (can be soaked in the billy as this can be boiled dry, or used to boiled the water later). Discard the initial water from the bag until the water level reaches the marked line, as this water is used to clean the outside of the bag (can be poured back into the bag if water scarce). Water normally takes 10-15 minute to drain through the bag, however, this is dependent on the turbidity of the water, large amounts of suspended matter tends to clog the bag increasing this time (if possible allow the water to settle before filtering). Tip, convenient trees to hang the millbank bag from near your water source are rare, therefore, cut three branches to form a tripod, makes life a lot simpler. The collected water should be bought to the boil i.e. the point at which the water bubbles furiously. Although not always required, to be safe, continue boiling at a rolling boil for a couple of minutes, some texts I’ve read say to boil for 20 minutes. I was told that scientifically speaking this was not required because as soon as the water reaches boiling point (100 degrees) all common harmfully bacteria and viruses will be killed, most are destroyed at 75 – 85 degrees. The reason for this discrepancy is probably to avoid confusion, people mistaking the early stages of boiling i.e. the pot starting to sing, small bubbles forming, with a true rolling boil. Another reason may be due to the amount of suspended material in the water i.e. non-filter water. These can provide refuge for bacteria etc, preventing them from being exposed to the full water temperature i.e. the barbequed sausage affect, burnt on the outside, raw in the middle. Note, boiling only kills living contaminants i.e. parasites, bacteria and viruses, chemical contaminants e.g. heavy metals, toxins produced by rotting material, sewage etc, will not be affected. Tips, its better to spend a little bit of time finding a ‘clean’ water source (running water) than trying to purify a ‘dirty’ one (stagnant water), do not re-boil water as this concentrates any chemical pollution, to speed up boiling keep the lid on the billy.
Figure 3.1.1 : Millbank filter
Figure 3.1.1.1 : Boiling, improvised filters
1. Image : reference - Handbok Overlevnad
An alternative to boiling filtered water is chemical purification i.e. chlorine and iodine. Chlorine doesn’t work as well in alkaline water, requiring additional time to purify water. Temperature also affects the speed at which chemical purifiers work. In general iodine is safer and more effective. Always follow the directions carefully:
Although purifying water by boiling is reliable and relatively simple it requires a fire and a fireproof container. Constructing a fire may not always be easy but with some basic knowledge as described in the fire section should be possible. Fireproof containers on the other hand may not always be available, therefore, an alternative approach that can be used for boiling water and cooking is stone / rock boiling. Rocks are heated in a fire, then transferred into a container to bring the water to a boil, being replaced with new rocks to maintain a rapid boil or simmer. As the container does not come into contact with the fire a wide range of options are now available. The simplest solution is to construct a bowl by digging a shallow hole in the ground, capable of holding a couple of litres (or more) and lining it with a waterproof material e.g. plastic sheet, waterproof clothing etc (in the article below rawhide was used). A more elegant solution (a lot more work) is to make a wooden bowl. The easiest way to do this is to split a suitably sized log with an axe, remove the bark and clean up the split face so that its relatively flat. Cut out a bowl using the axe, cutting across the grain as not to split the log, as shown in figure 3.1.2. Bowl depth is limited by the size of the axe’s blade i.e. a long shallow bowl is easy to make than a short deep one. Areas that can not be reached using the axe can be burnt out by placing embers into the bowl. This process can also be used to clean out rough cut marks and enlarge the bowl. If no suitable cutting tools are available the bowl can also be burnt out from the start. In the examples shown in figure 3.1.2 charcoal is burnt in the bowl, to produce the required embers. Burning out wood isn’t as easy as it may sound. Simply placing embers on the wood will not cause them to burn down into it to any depth i.e. most of the heat will escape upwards. To burn down into the wood use a tube to blow air onto the base of the ember to direct and accelerate the burning process. The tube restricts and focuses the air allowing you to maintain the air flow for a longer duration (the tube doesn’t have to come into contact with the ember so can be a reed, plastic tube etc). Tip, have a good supply of embers as this process takes a long time to complete, be careful not to burn too close to the edge or too thin as this can split the wood. When a bowl has formed knock out the remaining charred wood using a round stone i.e. the charred wood is brittle and easily pounded off, then repeat. I’ve read that the best woods to use to produce a bowl quickly are soft woods e.g. pine etc, and wood that has turned slightly punky, as these burn quickly. Finally, remove excess wood from the sides and level the bottom. The top example shown in figure 3.1.2 uses only burning to remove wood, after about an hour of burning to produce the embers and another half an hour of blowing only a 2 cm bowl has been formed. Compared to the bottom example that only took 15 minutes to shape using an axe. Again burning out the rough wood takes about the same time. Therefore, remove as much wood as possible using a cutting tool, as burning out wood is possible, but you do need a good supply of embers and quite a bit of time. Note, as the bowl is not varnished it will absorb water, swelling the wood fibres until it is waterproof. Below are some useful documents on burning out bowls ive found on the web (due to possible copyright conflicts these are only accessible from the local machine) :
Figure 3.1.2 : Making a wooden bowl
The general consensus seems to be that the best rocks to use for rock boiling are igneous rocks as they are less likely to fracture from the heat unlike sedimentary rocks that may explode when heated due to trapped moisture i.e. steam causing a rapid increase in pressure. For this reason only heat dry stones, not ones sourced directly from a river. There are three categories of rock:
Igneous rocks can be identified by the colour index as shown in figure 3.1.3. Light colours, including white, light gray, tan and pink, indicate felsic, rich in silica (SiO2). Dark colours, black and dark browns, indicate mafic, low in silica, but rich in iron (Fe) and magnesium (Mg). Note, igneous rocks can contain a mixture of light and dark coloured minerals. The texture of igneous rock i.e. its crystal size can vary a lot from very large crystals, fine grained textures, crystals of two different sizes, glassy or bubbly. Sedimentary rock identification is primarily based on texture - clastic, chemical, and biologic. Clastic sedimentary rocks contain clasts, fragments or pieces of rock or minerals e.g. clay / silt, sand or gravel. Chemical sedimentary rocks are identified by the minerals they contain - quartz, halite, gypsum and calcite. Biologic sedimentary rocks result from the accumulation of organic material or biologic activity e.g. shell or fossil fragments. Therefore, as a general rule, dark, fine grained rocks such as basalt are the one to go for. Tip, I’ve read that sandstone, flint, obsidian and quartz should be avoided. When choosing rocks match them to the size the bowl being used, something around about the size of a chicken egg or apple are good. Place the stones in a good fire and leave until hot, at least half an hour, have read they should be left for 2 hours. Then using forked sticks or wooden tongs transfer the rocks to your container. If the container has sufficient volume they can be dropped directly into the container, otherwise they must be held in the water with the tongs. Holding the stone in the water is also advisable if you are using a hole lined with plastic, to prevent the rock melting this waterproof lining. Tip, remember to have a good supply of rocks to maintain the boil.
Figure 3.1.3 : Igneous rocks
1. Image : reference -
A compliment to boiling or chemical purifiers are ceramic filters as shown in figure 3.1.4. Modern variants are siphon or pump driven, feeding water through a ceramic element removing suspended material and bacteria. However, the pores within the ceramic filter are too large to remove viruses, so the water must still be purified by boiling or chemical purifiers. Modern filters can also contain a second filter element containing iodine resin beads. These are negatively charged attracting the positively charged micro-organisms in the water, reducing the required iodine concentration, improving water taste. Note, the water still needs to be left the specified time to allow the chemical purifiers to take effect. In an emergency situation an improvised column filter can be made from a suitable container e.g. cone of birch bark, an old bowl, plastic bottle or can, as shown in figures 3.1.1.1 and 3.1.4. This is then filled with layers of charcoal, sand, grass, gravel and other suitable filtering materials e.g. cloth, sphagnum moss etc. Note, I’ve read that sphagnum moss (figure 3.1.4.1, found in wet, boggy areas) has a slight antiseptic property making it particularly effective. The course filter materials e.g. gravel, grass, sphagnum moss etc are placed on top, trapping suspended organic materials. Whilst the lower sand, peat etc layers filter out the smaller particles before the charcoal layer help remove bacteria and other chemical impurities. I’ve read that the charcoal should be broken up into pieces approximately 5mm in diameter, I assume to increase its surface area, but not too small as to be washed out of the filter. Charcoal is produced by heating wood in a container (without air), driving out the volatile materials as gas. The resulting charcoal (carbon) is very light as the material removed produces millions of tiny pores between the carbon atoms. This large surface area provides numerous bounding sites allowing the carbon to absorb / trap chemicals and bacteria as they pass through it. Even so, from what I’ve read it does not perform that well at removing pathogens, most of the emphasis seems to be on clearing and improving taste. To maximise performance the charcoal should be frequently renewed (charcoal cannot be regenerated). If this is not done or the filter is left unused for some time, the charcoal can become a breeding ground for bacteria. In general the deeper the container the better as this will allow more and larger layers of filtering material. When packing these layers ensure that they are well packed at the edges to prevent the water bypassing the filtering layers. Tip, water may need to be passed through the filter more than once, its also a good idea to have a final layer of gravel or sphagnum moss in the bottom of the filter to prevent the output holes from becoming blocked. Figure 3.1.1.1 shows two types of filter, down flow and up flow. The advantage of up flow filters are that they can be easily cleaned out by reversing the water flow, flushing out any trapped material.
An alternative to charcoal filtering are clay or ceramic filters. These vary from modern pump to traditional gravity driven clay pot filters, as shown in figure 3.1.4. Clay pot filters are still used in developing countries as they are easy to make and use. These filters are made from clay that has been mixed with a fine organic material. The clay is then formed into a container and fired, burning out the organic material creating a porous structure capable of filtering out suspended material and bacteria from the water poured into it. Note, in normal situations boil or use chemical purification as charcoal and ceramic filters do not remove viruses from the water.
Figure 3.1.4 : Charcoal, clay and ceramic filters
1. Image : reference -
Figure 3.1.4.1 : Sphagnum moss
Below are some useful documents on water and food hygiene I’ve found on the web (due to possible copyright conflicts these are only accessible from the local machine) :
One of the trickiest decisions to make is how much water do you need to carry. Ideally you would carry just enough water to reach the next water source, but this can not always be calculated. In general I normally find you need more than you would expect, for a days walk I would carry a minimum of 2 litres, however, this is highly dependent on temperature and levels of exertions. Tips, carry only purified water in drinking bottles, flood bottle threads to ensure purification of the bottle, do not touch bottle threads with your hands as this can lead to contamination. I have two main water containers, a British army water bottle (1 litre, in belt pouch) and standard camping water bottle (1 litre, in rucksack). Tip, when buying a water bottle consider bottle size (handling) and neck size (filling). In an emergency a convenient water container (pre-packed) is a strong plastic bag, with a line drawn on it indicating the water level for 1 litre (for chemical purifiers).
Figure 3.1.5 : Water containers
When backpacking the lack of water and clean cloths can lead to the temptation to go wild and not bother to have a proper wash. This is particularly true when you are first starting and haven’t found a daily routine and the correct equipment that suits your needs. Also of course it can be forced upon you when water is very limited. In normal situations the first thing to do in the morning is to have a good wash. The prospect of this can be a little daunting, requiring a bit of conviction to leave the warmth of your sleeping bag for the cold of the morning and the even colder wash. However, its worth doing, as this ritual wakes you up, re-adjusting your internal thermometer back to normality i.e. if you only have the warmth of your sleeping bag as a reference every morning will feel very cold, having a quick cold wash puts the mornings true temperature into prospective, meaning you don’t pile on extra layers of unnecessary clothing. Before washing take this opportunity to check for ticks, a folding mirror is a great help allowing you to check your back and those warm dark regions where they like to hide. Tip, deer ticks can be quite small so take your time. Don’t wash directly in your water source i.e. the river etc, wash on the land to allow the soap to disperse and break down in the ground. I don’t shave every day as I find that I cut up my face if there isn’t at least a bit of stubble to shave off (the joys of cold water shaving). It goes without saying, when brushing your teeth only use purified water. If water allows I do like to give my hair a quick wash and comb (give your hair a good comb every day anyway), otherwise I find my scalp starts to play up a bit after a few days of neglect (itchy, uncomfortable). Tip, before embarking on a trip have a hair cut, less hair to wash and dry. Although a towel is nice to have, they are bulky and never really dry (soon start to smell), so I don’t carry them. A small flannel does the job fine, making your water go further when washing, rung out can be used to dry with (well gets the worst off) and as its small dries quickly when tied to the back of the rucksack or a convenient tree. Tip, get a flannel with a loop or sew one on, to prevent it from being blown away when drying, also when your finished drying give the flannel a quick wash with soap and rise in water to keep it fresh. Washing and looking after your feet is another important task, to keep them in good condition i.e. prevent blisters and foot root, however, I tend to do this last thing at night before bed (as described in the medical and boot sections), no real reason, just seems the logical order.
To prevent tummy bugs soap and water are your best defence, always wash your hands before and after preparing food (take especial care when handling raw meat, game) and of course after the toilet. Tip, pour water for washing into a collapsible bowl, don’t wash your hands by pouring water over them from a drinking canteen as you could contaminate the container and you tend to waste more water this way. Tip, be very careful not to touch the inside or threads of a canteen to minimise the risk of water contamination. Another good idea is to chose an antibacterial soap / hand wash and to use a rub in hand sanitizer, as shown in figure 3.1.6. As with anything you put in your rucksack only carry enough for your needs, therefore, I decant the hand wash into a smaller container, an old plastic lemon juice bottle works well (screw top, inner top can be removed to allow it to be easily filled. An alternative to man made soaps are to use Horse chestnut (best), or Birch leaves, as these contain a natural soap like compound, as shown in figure 3.1.6.1 and 3.1.6.2. For Horse chestnut leaves strip off the thick central stems, then rub, crush a small handful of leaves between your hands. When the leaves have been bruised add a little water and squeeze out the liquid soap, this can be rubbed to produce a laver, not as thick as commercial soap but still an effective means of cleaning your hands etc. An alternative to, or emergency replacement for your toothbrush is to use an Alder (best) or Hazel stick. Select a suitably sized green stick and chew the end to form a brush, as shown in figure 3.1.6.3. Alder is easy to identify, likes wet soil, one of the few deciduous trees that has cones, figure 3.1.6.3 shows this years cones (green and closed) and the previous years (brown and open). The natural chemicals in Alder form a usable cleaning compound, this can be supplemented by using wood ash and salt (used salt, never had the desire to try ash).
Figure 3.1.6 : Soaps
Figure 3.1.6.1 : Horse chestnut leaves
Figure 3.1.6.2 : Birch leaves
Figure 3.1.6.3 : Alder trig toothbrush
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