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IAW FM 90-3
Desert Operations, Chapter 1
Section I. The Environment
Successful desert operations require adaptation to the environment and to the limitations its terrain and climate impose.
Equipment and tactics must be modified and adapted to a dusty and rugged landscape where temperatures vary from extreme highs down to freezing and where visibility may change from 30 miles to 30 feet in a matter of minutes.
Deserts are arid, barren regions of the earth incapable of supporting normal life due to lack of water.
Some species of animal and plant life have adapted successfully to desert conditions where annual rainfall may vary from 0 to 10 inches.
Figure 1-1. Deserts of the world.
Desert terrain also varies considerably from place to place, the sole common denominator being lack of water with its consequent environmental effects, such as sparse, if any, vegetation.
The basic land forms are similar to those in other parts of the world, but the topsoil has been eroded due to a combination of lack of water, heat, and wind to give deserts their characteristic barren appearance.
The bedrock may be covered by a flat layer of sand, or gravel, or may have been exposed by erosion.
Other common features are sand dunes, escarpments, wadis, and depressions, thus making it difficult for military operations.
Figure 1-2. Desert locations of the world.
Key terrain in the desert is largely dependent on the restrictions to movement that are present.
If the desert floor will not support wheeled vehicle traffic, the few roads and desert tracks become key terrain.
Crossroads are vital as they control military operations in a large area. Control of these passes are vital.
Desert warfare is often a battle for control of the lines of communication (LOC).
Types of Desert Terrain
There are three types of desert terrain:
Sandy or dune terrain
Mountain deserts are characterized by scattered ranges or areas of barren hills or mountains, separated by dry, flat basins.
High ground may rise gradually or abruptly from flat areas, to a height of several thousand feet above sea level.
Most of the infrequent rainfall occurs on high ground and runs off in the form of flash floods, eroding deep gullies and ravines and depositing sand and gravel around the edges of the basins.
Figure 1-3. Example of desert terrain
Rocky Plateau Deserts
Rocky plateau deserts are extensive flat areas with quantities of solid or broken rock at or near the surface.
They may be wet or dry, steep-walled eroded valleys, known as wadis, gulches, or canyons.
The National Training Center and the Golan Heights are examples of rocky plateau deserts.
Figure 1-4. Example of rocky plateau desert terrain
Sandy or Dune Deserts
Sandy or dune deserts are extensive flat areas covered with sand or gravel, the product of ancient deposits or modern wind erosion.
"Flat" is relative in this case, as some areas may contain sand dunes that are over 1,000 feet high and 10-15 miles long; trafficability on this type of terrain will depend on windward/leeward gradients of the dunes and the texture of the sand.
Other areas, however, may be totally flat for distances of 3,000 meters and beyond.
Figure 1-5. Example of sandy desert terrain
Figure 1-6. Example of dune desert terrain.
Roads and trails are rare in the open desert. Complex road systems beyond simple commercial links are not needed.
Rudimentary trails are used by minor caravans and nomadic tribesmen, with wells or oases approximately every 20 to 40 miles; although there are some waterless stretches which extend over 100 miles.
Vehicle travel in mountainous desert country may be severely restricted.
The following terrain features require special considerations regarding trafficability:
Wadis or dried water courses, vary from wide, but barely perceptible depressions of soft sand, dotted with bushes, to deep, steep-sided ravines.
Wadis can provide cover from ground observation and camouflage from visual air reconnaissance.
The threat of flash floods after heavy rains poses a significant danger to troops and equipment downstream.
Figure 1-7. Example of a wadi.
The ruins of earlier civilizations, scattered across the deserts of the world, often are sited along important avenues of approach and frequently dominate the only available passes in difficult terrain.
of these positions maybe imperative for any force intending to dominate the immediate area.
Currently occupied dwellings have little impact on trafficability except that they are normally located near roads and trails.
Figure 1-8. Example of desert nomads.
Figure 1-9. Command man-made desert structures.
The highest known ambient temperature recorded in a desert was 136 degrees Fahrenheit (58 degrees Celsius).
Winter temperatures in Siberian deserts and in the Gobi reach minus 50 degrees Fahrenheit (minus 45 degrees Celsius).
Low temperatures are aggravated by very strong winds producing high wind-chill factors.
The cloudless sky of the desert permits the earth to heat during sunlit hours, yet cool to near freezing at night.
Desert winds can achieve velocities of near hurricane force; dust and sand suspended within them make life intolerable, maintenance very difficult, and restrict visibility to a few meters.
Although there is no danger of a man being buried alive by a sandstorm, individuals can become separated from their units.
In all deserts, rapid temperature changes invariably follow strong winds. Even without wind, the telltale clouds raised by wheels, tracks, and marching troops give away movement.
Wind aggravates the problem. As the day gets warmer the wind increases and the dust signatures of vehicles may drift downwind for several hundred meters.
In many deserts a prevailing wind blows steadily from one cardinal direction for most of the year, and eventually switches to another direction for the remaining months.
The equinoctial gales raise huge sandstorms that rise to several thousand feet and may last for several days. Gales and sandstorms in the winter months can be bitterly cold.
The lack of water is the most important single characteristic of the desert. The population, if any, varies directly with local water supply. A Sahara oasis may, for its size, be one of the most densely occupied places on earth (see Figure 1-12 for a typical oasis).
Figure 1-12. Typical oasis.
Desert rainfall varies from one day in the year to intermittent showers throughout the winter.
Severe thunderstorms bring heavy rain, and usually far too much rain falls far too quickly to organize collection on a systematic basis. The water soon soaks into the ground and may result in flash floods.
Whenever possible, as storms approach, vehicles should move to rocky areas or high ground to avoid flash floods and becoming mired.
Subsurface water may be so far below the surface, or so limited, that wells are normally inadequate to support any great number of people. Because potable water is absolutely vital, a large natural supply may be both tactically and strategically important. Destruction of a water supply system may become a political rather than military decision, because of its lasting effects on the resident civilian population.
When there is no surface water, tap into the earth's water table for ground water. Access to this table and its supply of generally pure water depends on the contour of the land and the type of soil.
Figure 1-13. Water Tables.
Finding water from Rocky Soil
Look for springs and seepages. Limestone has more and larger springs than any other type rock. Because limestone is easily dissolved, caverns are readily etched in it by ground water. Look in these caverns for springs.
Lava rock is a good source of seeping ground water because it is porous.
Finding water from Rocky Soil cont.
Watch for water indicators in desert environments. Some signs to look for are the direction in which certain birds fly, the location of plants, and the convergence of game trails.
Look for these signs and dig. If you do not have a bayonet or entrenching tool, dig with a flat rock or sharp stick.
Desert natives often know of lingering surface pools in low places. They cover their surface pools, so look under brush heaps or in sheltered nooks, especially in semiarid and brush country.
Finding water from Rocky Soil cont.
Places that are visibly damp, where animals have scratched, or where flies hover, indicate recent surface water. Dig in such places for water.
Collect dew on clear nights by sponging it up with a handkerchief. During a heavy dew you should be able to collect about a pint an hour.
Dig in dry stream beds because water may be found under the gravel. When in snow fields, put in a water container and place it in the sun out of the wind.
Water from plants.
If unsuccessful in your search for ground or runoff water, or if you do not have time to purify the questionable water, a water-yielding plant may be the best source. Clear sap from many plants is easily obtained. This sap is pure and is mostly water.
Water from plants cont.
Plant tissues. Many plants with fleshy leaves or stems store drinkable water. Try them wherever you find them.
The barrel cactus of the southwestern United States is a possible source of water.
Use it only as a last resort and only if you have the energy to cut through the tough, spine-studded outer rind.
Figure 1-14. Barrel cactus as a possible source of water.
Water from plants cont.
Roots of desert plants. Desert plants often have their roots near the surface. The Australian water tree, desert oak, and blood wood are some examples. Pry these roots out of the ground, cut them into 24-36 inch lengths, remove the bark, and suck the water.
Water from plants cont.
Vines. Not all vines yield palatable water, but try any vine found. Use the following method for tapping a vine--it will work on any species:
Step 1. Cut a deep notch in the vine as high up as you can reach.
Step 2. Cut the vine off close to the ground and let the water drip into your mouth or into a container.
Step 3. When the water ceases to drip, cut another section off the top. Repeat this until the supply of fluid is exhausted.
Water from plants cont.
Palms. Burl, coconut, sugar and nipa palms contain a drinkable sugary fluid. To start the flow in coconut palm, bend the flower stalk downward and cut off the top. If a thin slice is cut off the stalk every 12 hours, you can renew the flow and collect up to a quart a day.
Water from plants cont.
Coconut. Select green coconuts. They can be opened easily with a knife and they have more milk than ripe coconuts. The juice of a ripe coconut is extremely laxative; therefore, do not drink more than three or four cups a day.
The milk of a coconut can be obtained by piercing two eyes of the coconut with a sharp object such as a stick or a nail. To break off the outer fibrous covering of the coconut without a knife, slam the coconut forcefully on the point of a rock or protruding stump.
Invertebrates such as ground-dwelling spiders, scorpions, and centipedes, together with insects of almost every type, are in the desert.
Drawn to man as a source of moisture or food, lice, mites, and flies can be extremely unpleasant and carry diseases such as scrub typhus and dysentery.
Scorpions are prevalent in desert regions. particularly active at night.
Scorpions hide in clothing, boots, or bedding, so troops should routinely shake these items before using. Although scorpion stings are rarely fatal, they can be painful.
Scorpions are They prefer damp locations and are easily recognizable by their crab-like appearance, and by their long tail which ends in a sharp stinger.
Flies are abundant throughout desert environments. Filth-borne disease is a major health problem posed by flies. Dirt or insects in the desert can cause infection in minor cuts and scratches.
Avoid all dogs and rats which are the major carriers of fleas. Fleas are the primary carriers of plague and murine typhus.
Reptiles are perhaps the most characteristic group of desert animals. Lizards and snakes occur in quantity, and crocodiles are common in some desert rivers. Lizards are normally harmless and can be ignored; although exceptions occur in North America and Saudi Arabia.
Snakes, ranging from the totally harmless to the lethal, abound in the desert. A bite from a poisonous snake under two feet long can easily become infected. Snakes seek shade (cool areas) under bushes, rocks, trees, and shrubs.
These areas should be checked before sitting or resting. Troops should always check clothing and boots before putting them on.
Vehicle operators should look for snakes when initially conducting before-operations maintenance. Look for snakes in and around suspension components and engine compartments as snakes may seek the warm areas on recently parked vehicles to avoid the cool night temperatures.
Sand vipers have two long and distinctive fangs that may be covered with a curtain of flesh or folded back into the mouth. Sand vipers usually are aggressive and dangerous in spite of their size.
A sand viper usually buries itself in the sand and may strike at a passing man; its presence is alerted by a characteristic coiling pattern left on the sand.
The Egyptian cobra can be identified by its characteristic cobra combative posture. In this posture, the upper portion of the body is raised vertically and the head tilted sharply forward. The neck is usually flattened to form a hood.
The Egyptian cobra is often found around rocky places and ruins and is fairly common. The distance the cobra can strike in a forward direction is equal to the distance the head is raised above the ground.
Poking around in holes and rock piles is particularly dangerous because of the likelihood of encountering a cobra.
Figure 1-16. Sand viper and cobra
Camels: The urine of the camel is very concentrated to reduce water loss, allowing it to lose 30 percent of its body weight without undue distress.
A proportionate loss would be fatal to man. The camel regains this weight by drinking up to 27 gallons (120 liters) of water at a time. It cannot, however, live indefinitely without water and will die of dehydration as readily as man in equivalent circumstances.
Desert mammals cont.
Dogs: are often found near mess facilities and tend to be in packs of 8 or 10. Dogs are carriers of rabies and should be avoided. Commanders must decide how to deal with packs of dogs; extermination and avoidance are two options.
Dogs also carry fleas which may be transferred upon bodily contact. Rabies is present in most desert mammal populations. Do not take any chances of contracting fleas or rabies from any animal by adopting pets.
Rats: Rats are carriers of various parasites and gastrointestinal diseases due to their presence in unsanitary locations.
Time for a break?
Section II. Environmental Effects on Personnel
There is no reason to fear the desert environment, and it should not adversely affect the morale of a soldier/marine who is prepared for it. Lack of natural concealment has been known to induce temporary agoraphobia (fear of open spaces) in some troops new to desert conditions, but this fear normally disappears with acclimatization.
Environmental Effects on Personnel cont.
Remember that there is nothing unique about either living or fighting in deserts; native tribesmen have lived in the Sahara for thousands of years.
The desert is neutral, and affects both sides equally; the side whose personnel are best prepared for desert operations has a distinct advantage.
Environmental Effects on Personnel cont.
The desert is fatiguing, both physically and mentally. A high standard of discipline is essential, as a single individual's lapse may cause serious damage to his unit or to himself. Commanders must exercise a high level of leadership and train their subordinate leaders to assume greater responsibilities required by the wide dispersion of units common in desert warfare.
Environmental Effects on Personnel cont.
Every soldier/marine must clearly understand why he is fighting in such harsh conditions and should be kept informed of the operational situation.
Welfare is an essential factor in the maintenance of morale in a harsh environment, especially to the inexperienced.
Troops must be kept healthy and physically fit; they must have adequate, palatable, regular food, and be allowed periods of rest and sleep.
The extreme heat of the desert can cause heat exhaustion and heatstroke and puts troops at risk of degraded performance. For optimum mental and physical performance, body temperatures must be maintained within narrow limits.
Thus, it is important that the body lose the heat it gains during work. The amount of heat accumulation in the human body depends upon the amount of physical activity, level of hydration, and the state of personal heat acclimatization.
Unit leaders must monitor their troops carefully for signs of heat distress and adjust schedules, work rates, rest, and water consumption according to conditions.
If the body fluid lost through sweating is not replaced, dehydration will follow. This will hamper heat dissipation and can lead to heat illness. When humidity is high, evaporation of sweat is inhibited and there is a greater risk of dehydration or heat stress. Consider the following to help prevent dehydration:
Heat, wind, and dry air combine to produce a higher individual water requirement, primarily through loss of body water as sweat. Sweat rates can be high even when the skin looks and feels dry.
Dehydration nullifies the benefits of heat acclimatization and physical fitness, it increases the susceptibility to heat injury, reduces the capacity to work, and decreases appetite and alertness. A lack of alertness can indicate early stages of dehydration.
Thirst is not an adequate indicator of dehydration. The soldier/marine will not sense when he is dehydrated and will fail to replace body water losses, even when drinking water is available. The universal experience in the desert is that troops exhibit "voluntary dehydration" that is, they maintain their hydration status at about 2 percent of body weight (1.5 quarts) below their ideal hydration status without any sense of thirst.
Chronic dehydration increases the incidence of several medical problems: constipation (already an issue in any field situation), piles (hemorrhoids), kidney stones, and urinary infections. The likelihood of these problems occurring can be reduced by enforcing mandatory drinking schedules.
Resting on hot sand will increase heat stress--the more a body surface is in contact with the sand, the greater the heat stress. Ground or sand in full sun is hot, usually 30-45 degrees hotter than the air, and may reach 150 degrees Fahrenheit when the air temperature is 120 degrees Fahrenheit. Cooler sand is just inches below the surface; a shaded trench will provide a cool resting spot.
At the first evidence of heat illness, have the troops stop work, get into shade, and rehydrate. Early intervention is important. Soldiers/ marines who are not taken care of can become more serious casualties.
Acclimatization to heat is necessary to permit the body to reach and maintain efficiency in its cooling process.
A period of approximately 2 weeks should be allowed for acclimatization, with progressive increases in heat exposure and physical exertion. Significant acclimatization can be attained in 4-5 days, but full acclimatization takes 7-14 days, with 2-3 hours per day of exercise in the heat
Climatic stress on the human body in hot deserts can be caused by any combination of air temperature, humidity, air movement, and radiant heat. The body is also adversely affected by such factors as lack of acclimatization, being overweight, dehydration, alcohol consumption, lack of sleep, old age, and poor health.
The body maintains its optimum temperature of 98.6 degrees Fahrenheit by conduction/convection, radiation, and evaporation (sweat). The most important of these in the daytime desert is evaporation, as air temperature alone is probably already above skin temperature.
Radiant light comes from all directions. The sun's rays, either direct or reflected off the ground, affect the skin and can also produce eyestrain and temporarily impaired vision. Not only does glare damage the eyes but it is very tiring; therefore, dark glasses or goggles should be worn.
Overexposure to the sun can cause sunburn. Persons with fair skin, freckled skin, ruddy complexions, or red hair are more susceptible to sunburn than others, but all personnel are susceptible to some degree.
Radiant Light cont.
Sunburn is characterized by painful reddened skin, and can result in blistering and lead to other forms of heat illness.
The sun is as dangerous on cloudy days as it is on sunny days.
Sunburn ointment is not designed to give complete protection against excessive exposure.
Sunbathing or dozing in the desert sun can be fatal.
The wind can be as physically demanding as the heat, burning the face, arms, and any exposed skin with blown sand. Sand gets into eyes, nose, mouth, throat, lungs, ears, and hair, and reaches every part of the body. Even speaking and listening can be difficult.
The combination of wind and dust or sand can cause extreme irritation to mucous membranes, chap the lips and other exposed skin surfaces, and can cause nosebleed. Cracked, chapped lips make eating difficult and cause communication problems.
When visibility is reduced by sandstorms to the extent that military operations are impossible, soldiers/marines should not be allowed to leave their group for any purpose unless secured by lines for recovery.
The following are special considerations when performing operations in dust or sand:
Contact lenses are very difficult to maintain in the dry dusty environment of the desert and should not be worn except by military personnel operating in air conditioned environments, under command guidance.
Mucous membranes can be protected by breathing through a wet face cloth, snuffing small amounts of water into nostrils (native water is not safe for this purpose) or coating the nostrils with a small amount of petroleum jelly. Lips should be protected by lip balm.
Moving vehicles create their own sandstorms and troops traveling in open vehicles should be protected.
Scarves and bandannas can be used to protect the head and face.
The face should be washed as often as possible. The eyelids should be cleaned daily.
Maintaining safe, clean, water supplies is critical. The best containers for small quantities of water (5 gallons) are plastic water cans or coolers. Water in plastic cans will be good for up to 72 hours; storage in metal containers is safe only for 24 hours.
Water trailers, if kept cool, will keep water fresh up to five days. If the air temperature exceeds 100 degrees Fahrenheit, the water temperature must be monitored. When the temperature exceeds 92 degrees Fahrenheit, the water should be changed, as bacteria will multiply.
WATER SUPPLY cont.
If the water is not changed the water can become a source of sickness, such as diarrhea. Ice in containers keeps water cool.
If ice is put in water trailers, the ice must be removed prior to moving the trailer to prevent damage to the inner lining of the trailer.
Potable drinking water is the single most important need in the desert. Ensure nonpotable water is never mistaken for drinking water.
Water that is not fit to drink but is not otherwise dangerous (it may be merely oversalinated) may be used to aid cooling. It can be used to wet clothing, for example, so the body does not use too much of its internal store of water.
WATER SUPPLY cont.
Use only government-issued water containers for drinking water. Carry enough water on a vehicle to last the crew until the next planned resupply. It is wise to provide a small reserve. Carry water containers in positions that-
Prevent vibration by clamping them firmly to the vehicle body.
Are in the shade and benefit from an air draft.
Are protected from puncture by shell splinters.
Are easily dismounted in case of vehicle evacuation.
WATER SUPPLY cont.
All unit leaders must understand the critical importance of maintaining the proper hydration status. Almost any contingency of military operations will act to interfere with the maintenance of hydration. Urine provides the best indicator of proper hydration. The following are considerations for proper hydration during desert operations:
WATER SUPPLY cont.
Water is the key to your health and survival. Drink before you become thirsty and drink often, When you become thirsty you will be about a "quart and a half low".
Carry as much water as possible when away from approved sources of drinking water. Man can live longer without food than without water.
Drink before you work; carry water in your belly, do not "save" it in your canteen. Learn to drink a quart or more of water at one time and drink frequently to replace sweat losses.
Ensure troops have at least one canteen of water in reserve, and know where and when water re-supply will be available.
WATER SUPPLY cont.
Carbohydrate/electrolyte beverages (e.g., Gatorade) are not required, and if used, should not be the only source of water. They are too concentrated to be used alone. Many athletes prefer to dilute these 1:1 with water. Gaseous drinks, sodas, beer, and milk are not good substitutes for water because of their dehydrating effects.
If urine is more colored than diluted lemonade, or the last urination cannot be remembered, there is probably insufficient water intake. Collect urine samples in field expedient containers and spot check the color as a guide to ensuring proper hydration. Very dark urine warns of dehydration. Soldiers/marines should observe their own urine, and use the buddy system to watch for signs of dehydration in others.
WATER SUPPLY cont.
Diseases, especially diarrheal diseases, will complicate and often prevent maintenance of proper hydration.
Salt, in correct proportions, is vital to the human body; however, the more a man sweats, the more salt he loses.
Unacclimatized troops need additional salt during their first few days of exposure and all soldiers/marines need additional salt when sweating heavily.
Water must be tested before adding salt as some sources are already saline, especially those close to the sea.
The desert can be combine to produce dangerously cold. The dry air, wind, and clear sky can bone-chilling discomfort and even injury. The ability of the body to maintain body temperature within a narrow range is as important in the cold as in the heat.
Hypothermia is the major threat from the cold in the desert, but frostbite also occurs.
Troops must have enough clothing and shelter to keep warm.
Troops maybe tempted to leave clothing and equipment behind that seems unnecessary (and burdensome) during the heat of the day.
Some guidelines to follow when operating in the cold are-
Anticipate an increased risk of cold-wet injuries if a proposed operation includes lowland or marshes. Prolonged exposure of the feet in cold water causes immersion foot injury, which is completely disabling.
Check the weather-know what conditions you will be confronting. The daytime temperature is no guide to the nighttime temperature; 90-degree-Fahrenheit days can turn into 30-degree-Fahrenheit nights.
The effects of the wind on the perception of cold is well known. Wind-chill charts contained in FM 21-10 allow estimation of the combined cooling power of air temperature and wind speed compared to the effects of an equally cooling still-air temperature.
Uniforms should be worn to protect against sunlight and wind. Wear the uniform loosely. Use hats, goggles, and sunscreen. Standard lightweight clothing is suitable for desert operations but should be camouflaged in desert colors, not green.
Wear a scarf or triangular bandanna loosely around the neck (as a sweat rag) to protect the face and neck during sandstorms against the sand and the sun. In extremely hot and dry conditions a wet sweat rag worn loosely around the neck will assist in body cooling.
Combat boots wear out quickly in desert terrain, especially if the terrain is rocky. The leather dries out and cracks unless a nongreasy mixture such as saddle soap is applied. Covering the ventilation holes on jungle boots with glue or epoxies prevents excessive sand from entering the boots.
Change socks when they become wet. Prolonged wear of wet socks can lead to foot injury. Although dry desert air promotes evaporation of water from exposed clothing and may actually promote cooling, sweat tends to accumulate in boots.
Compared to the desert battle dress uniform (DBDU) the relative impermeability of the battle dress over garment (BDO) reduces evaporative cooling capacity. Wearing underwear and the complete DBDU, with sleeves rolled down and under the chemical protective garment, provides additional protection against chemical poisoning. However, this also increases the likelihood of heat stress casualties.
HYGIENE AND SANITATION
Personal hygiene is absolutely critical to sustaining physical fitness. Take every opportunity to wash. Poor personal hygiene and lack of attention to sitting of latrines cause more casualties than actual combat.
Hygiene and sanitation are covered in detail in FM 21-10.
Diseases common to the desert include plague, typhus, malaria, dengue fever, dysentery, cholera, and typhoid. Diseases which adversely impact hydration, such as those which include nausea, vomiting, and diarrhea among their symptoms, can act to dramatically increase the risk of heat (and cold) illness or injury.
Infectious diseases can result in a fever; this may make it difficult to diagnose heat illness. Occurrences of heat illness in troops suffering from other diseases complicate recovery from both ailments.
DESERT SICKNESS cont.
The following are additional health-related considerations when operating in a desert environment:
The most common and significant diseases in deserts include diarrheal and insect borne febrile (i.e., fever causing) illnesses-both types of these diseases are preventable.
Most diarrheal diseases result from ingestion of water or food contaminated with feces. Flies, mosquitoes, and other insects carry fever-causing illnesses such as malaria, sand fly fever, dengue (fever with severe pain in the joints), typhus, and tick fevers.
There are no safe natural water sources in the desert. Standing water is usually infectious or too brackish to be safe for consumption. Units and troops must always know where and how to get safe drinking water.
DESERT SICKNESS cont.
Avoid brackish water (i.e., salty). It, like sea water, increases thirst; it also dehydrates the soldier/marine faster than were no water consumed. Brackish water is common even in public water supplies, Iodine tablets only kill germs, they do not reduce brackishness.
Water supplies with insufficient chlorine residuals, native food and drink, and ice from all sources are common sources of infective organisms.
Take a break.
Section III. Environmental Effects on Equipment
Environmental Effects on Equipment
Conditions in an arid environment can damage military equipment and facilities. Temperatures and dryness are major causes of equipment failure, and wind action lifts and spreads sand and dust, clogging and jamming anything that has moving parts.
Ten characteristics of the desert environment may adversely affect equipment used in the desert:
Environmental Effects on Equipment cont.
Dust and sand.
Optical path bending.
The relative importance of each characteristic varies from desert to desert. Humidity, for example, can be discounted in most deserts but is important in the Persian Gulf.
Terrain varies from nearly flat, with high trafficability, to lava beds and salt marshes with little or no trafficability. Drivers must be well trained in judging terrain over which they are driving so they can select the best method of overcoming the varying conditions they will encounter.
Wheel vehicles may be acceptable as they can go many places that track vehicles can go; however, their lower speed average in poor terrain maybe unacceptable during some operations.
Vehicles should be equipped with extra fan belts, tires, (and other items apt to malfunction), tow ropes (if not equipped with a winch), extra water cans, and desert camouflage nets. Air-recognition panels, signal mirrors, and a tarpaulin for crew sun protection are very useful.
Operators must be fully trained in operating and maintaining their equipment. Some types of terrain can have a severe effect on suspension and transmission systems, especially those of wheel vehicles.
Increase the unit PLL of tires and tracks as sand temperatures of 165 degrees Fahrenheit are extremely detrimental to rubber, and weaken resistance to sharp rocks and plant spines.
Vehicle coding and lubrication systems are interdependent. A malfunction by one will rapidly place the other system under severe strain. In temperature extremes, all types of engines are apt to operate above optimum temperatures, leading to excessive wear, or leaking oil seals in the power packs, and ultimately, engine failure. Commanders should be aware which types of vehicles are prone to excessive overheating, and ensure extra care is applied to their maintenance.
Ammunition must be out of direct heat and sunlight. Use camouflage nets and tarpaulins to provide cover. Ammunition cool enough to be held by bare hands is safe to fire.
Radiators require special attention. Proper cooling-system operation is critical in high-temperature environments. Check cooling systems for serviceability prior to deployment. Local water maybe high in mineral content which will calcify in cooling systems. Distilled water is better since tap water contains chemicals that will form a crusty coating inside the radiator and will ultimately clog it.
The major problem with radios in a desert environment is overheating. The following steps can help prevent overheating of radios:
Keep radios out of direct sunlight.
Place a piece of wood on top of the radio. Leaving space between the wood and the top of the radio will help cool the equipment. Operating on low power whenever possible will also help.
Place wet rags on top of radios to help keep them cool and operational. Do not cover the vents.
Desert winds, by their velocity alone, can be very destructive to large and relatively light materiel such as aircraft, tentage, and antenna systems. To minimize the possibility of wind damage, materiel should be sited to benefit from wind protection and should be firmly picketed to the ground.
DUST AND SAND
Keeping sand out of maintenance areas is critical due to the strong possibility of sand or dust entering the cylinders or other moving parts when the equipment is stripped. Baggies, cloth, or plastic can be used to protect open or disassembled components from blowing sand and dust.
Dust and sand can easily cause failure of such items as radio and signal distribution panels, and circuit breakers, and cause small electrical motors to burn out.
DUST AND SAND cont.
Radio is the primary means of communications in the desert. It can be employed effectively in desert climates and terrain to provide the reliable communications demanded by widely dispersed forces. However, desert terrain provides poor electrical ground, and a counterpoise (an artificial ground) is needed to improve the range of certain antennas.
Some receiver-transmitters have ventilating ports and channels that can get clogged with dust. These must be checked regularly and kept clean to prevent overheating.
Mobile subscriber equipment may require the deployment of additional radio access units (RAU) AN/VRC-191. These assemblages are the primary link for the mobile subscriber radio telephone terminal (MSRT) AN/VRC-97s which are located down to battalion level. The normal operating range of the receiver-transmitter used with these radios may only be 10 kilometers in the desert.
DUST AND SAND cont.
Dust and sand adversely affect the performance of weapons. Weapons may jam or missiles lock on launching rails due to sand and dust accumulation.
Sand- or dust-clogged barrels lead to in-bore detonations. Daily supervised cleaning of weapons is essential.
Particular attention should be given to magazines which are often clogged, interrupting the feeding of weapons.
Paintbrushes are among the most useful tools to bring to the desert; they are extremely effective in cleaning weapons and optics.
DUST AND SAND cont.
Take precautions to prevent exposure of floppy disks and computers to dust or sand. Covering them in plastic bags is a technique that has worked for several different units.
Compressed air cans, locally purchased from computer vendors, will facilitate the cleaning of keyboards and other components of computer systems.
Some deserts are humid. Where this is the case, humidity plus heat encourages rust on bare metal and mold in enclosed spaces such as optics. Bare metal surfaces on equipment not required for immediate use must be kept clean and very lightly lubricated.
In deserts with relatively high-dew levels and high humidity, overnight condensation can occur wherever surfaces (such as metal exposed to air) are cooler than the air temperature. Condensation can affect such items as optics, fuel lines, and air tanks. Drain fuel lines both at night and in the morning (whenever necessary). Clean optics and weapons frequently. Weapons, even if not lubricated, accumulate sand and dirt due to condensation.
Static electricity is prevalent and poses a danger in the desert. It is caused by atmospheric conditions coupled with an inability to ground out due to dryness of the terrain. It is particularly prevalent with aircraft or vehicles having no conductor contact with the soil.
The difference of electrical potential between separate materials may cause an electrical discharge between them when contact is made, and if flammable gases are present, they may explode and cause a fire. Poor grounding conditions aggravate the problem.
Be sure to tape all sharp edges (tips) of antennas to reduce wind-caused static electricity. If you are operating from a fixed position, ensure that equipment is properly grounded.
STATIC ELECTRICITY cont.
Establish a metal circuit between fuel tankers and vehicles before and during refueling. Ensure the fuel tankers and vehicles are grounded (for example, by a cable and picket or by a crowbar). Grounding of vehicles and equipment should be accomplished in accordance with appropriate operations manuals.
Static electricity will also ruin circuit boards and other electronic equipment.
Radiant light may be detrimental to plastics, lubricants, pressurized gases, some chemicals, and infrared tracking and guidance systems. Items like CO² fire extinguishers, M13 decontamination and reimpregnating kits, and Stinger missiles must be kept out of constant direct sunlight. Optics have been known to discolor under direct sunlight (although this is unusual), so it is wise to minimize their exposure to the sun's rays.
End of the presentation.