Hydrology-From Measurement To Hydrological Information (8)



The WMO technology transfer system, the
Hydrological Operational Multipurpose System
(HOMS), in operation since 1981, offers a simple
but effective means of disseminating a wide range
of proven techniques for use by hydrologists.
Particular reference is made to section A00 of the
HOMS Reference Manual, which covers policy,
planning and organization. This chapter, on safety
considerations in hydrometry, complements
preceding chapters that provide an overview of the
hydrological instruments and methods of observation, by proposing safety measures needed to support the operating activities of hydrologists.

Hydrological measurements are made under an
extremely wide range of conditions, many of which
are potentially hazardous to the personnel making
them. Knowledge of the hazards and the means by
which they can be minimized are essential for
hydrological personnel. A number of agencies have
produced detailed and informative safety manuals.
Familiarization with this material is highly recommended to hydrologists and technicians.

Each State may have its own safety standards and
practices as well as laws and regulations governing
safety. Additionally, at particular sites, there may be
specific safety precautions which hydrological
personnel would be expected to observe. Many of
these are outlined in this chapter.

Each member of a hydrometric fi eld-team has the
responsibility for his or her own personal safety and
that of the other team members in carrying out his
or her work. Organizations have the responsibility
to promote an awareness of hazards and work practices needed to minimize risks, and to provide
appropriate safety equipment and training.

8.2.1 Access
Well-constructed footpaths, steps, ladders and the
like are essential for safety on steep riverbanks.
These need to be constructed for safe access in wet
weather and possibly in the dark. When construction
of a station begins, the access should be completed
8.2.2 Platforms
High platforms and catwalks should have a nonslip surface, such as fine wire mesh fastened over
timber planks. Handrails should also be fitted.
8.2.3 Wells
Some water-level recording stations have deep wells
that must be entered occasionally for maintenance.
Hazards exist owing to the possibility of falling and
the presence of gases. All wells should have at least a
simple rope, pulley and winch system installed so that
a person can be rescued from the bottom of the well.
Persons descending into wells that are deep or are
in any way suspected to contain gas must wear a
safety harness attached to a rescue system, with one
or more people in attendance at the top. A safety
helmet should also be worn.
A number of gases, including carbon dioxide, methane and hydrogen sulphide, may be present in a
well. They are produced from decomposing organic
material and may displace air, leading to an oxygen
deficiency as well as toxicity and flammability.
These dangers can occur with quite low concentrations, and reaction to the gases may be quite rapid,
with a person becoming unconscious after only one
or two inhalations of a toxic gas.
Precautions include proper ventilation in all wells
over 6 m in depth, opening wells for ventilation
prior to entry, forbidding flames or smoking, use of
gas monitoring equipment, and the routine use of
safety harnesses and rescue equipment. All efforts
should be made to exclude or remove organic matter
from wells. The hazards of slipping can be minimized
by having properly constructed ladders and by maintaining all equipment in good condition.

The main hazards in carrying out measurements or
sampling from bridges are getting struck by passing traffi c or being tipped over the side of the bridge by
undue force or weight on the suspended equipment.
8.3.1 Traffic hazards
Bridges with a pedestrian lane may provide a good
margin of safety. In other circumstances, it is imperative to warn motorists with adequate signs and, if
practical, flashing lights. Personnel should wear
fluorescent or brightly coloured clothing, and portable traffic markers may be deployed to shift traffic
flow away from the work area. If it is necessary to
interface with traffic, arrangements should be made
with the local authorities. In areas where there are
FM radio stations, it is important to announce the
schedules of the hydrological activities, so that the
public may be made aware.
8.3.2 Hazards from suspended
The potential leverage on equipment, such as
gauging frames, indicates that they are prone to
being tipped over the side of the bridge if the
suspended equipment should become caught on
river-borne debris or on boats passing below. Extra
care should be taken against these dangers during
Gauging cranes or frames need to be suitably counterbalanced or tied down. The overturning moment
of vehicle-mounted cranes should be calculated
and shear pins incorporated in the equipment, if
necessary, to prevent capsizing. Over navigable
water, the presence of all cables should be indicated
by the attachment of marker fl ags.
8.4.1 General
Where it is possible to wade streams, hydrological
measurements may be made more simply and
directly than by other means. However, it becomes
hazardous when the depth or velocity, or both, are
excessive. Personnel must not be obligated to wade
streams in situations where they feel unsafe.
Experience and confidence are important factors,
but must be tempered with sensible caution.
8.4.2 Assessing the situation
Personnel need to exercise caution and be experienced enough to decide whether wading should be
carried out in a particular situation. As a general
guide, if the product of the depth in metres and the
velocity in metres per second exceed 1.0, the stream
is unlikely to be safe to wade. A person’s build and
attire will influence this decision. Waders have
more drag than bare legs or wetsuits.
8.4.3 Wearing of life jackets
Correctly fastened life jackets of an appropriate size
and design should generally be worn in flowing
water above crotch level, where there is need to
enter such water or where conditions could become
8.4.4 Safety lines and taglines
When making discharge measurements, a rope or
line strung across the river can be useful as a support.
It can also serve as a line for measuring distance
and should be securely anchored at both ends to
sustain the weight and drag of a person against the
fl ow of the river.
8.4.5 Wading technique
One should select a crossing with negotiable depths,
velocities and bed material, plan a route diagonally
downstream, and walk across with short steps,
facing the opposite bank, and side-on to the current.
It can be helpful to use a wading rod (without
current meter) on the upstream side to probe the
depth and provide support. It is preferable to brace
against the current, remain calm and not hurry. If
the crossing becomes too difficult, one should
retreat, possibly by stepping backward until it is
possible to turn around, and perhaps try an easier
8.4.6 In case of mishap
If one begins to be swept downstream, one should
go with the current and head towards the bank,
propelling oneself with the arms outstretched and
pushing with the feet. If the bed is rocky, the natural reaction to put the feet down should be avoided
as they may be caught between the rocks. If this
occurs, a person can easily be pushed underwater
by the current with fatal results.
If the water is deep and it is necessary to swim some
distance, waders may need to be removed. The best
way is to work them down to the hips and pull the
feet out one at a time. One should avoid turning
them inside out and should refrain from this operation where the water is shallow and the waders are
likely to become snagged. Wader straps should be fastened in such a manner that they can readily be undone.

It is possible to trap air in waders so that they
aid buoyancy, either by wearing a belt tightly
fastened around the waist or by quickly assuming a floating position on one’s back with the
knees drawn up.

8.5.1 General
Many types of boats are used for hydrological
purposes, each having their own safety requirements. These must always be observed, as boating
is inherently dangerous
. The boat operator must
be familiar with all operating and emergency
procedures, and all regulations governing the
intended operations. These may include testing
the lights of the boat, watching the weather and
equipping the boat with appropriate clothing for
variable weather conditions, a radio and emergency supplies. Alcohol or drugs should never be
consumed during boat operations. Craft must be
in good repair, adequate for the conditions that
could be encountered, and must not be
8.5.2 Life jackets and safety equipment
Life jackets must be worn at all times in small craft.
In larger craft, there must be a sufficient number of
life jackets on board for all passengers and crew.
Each boat must carry a full inventory of safety
equipment that is appropriate to the type of craft
and the conditions that could be encountered.
These items may include all or some of the following: life raft, flares, lifebelts, bailer, bilge pumps,
safety harnesses and survival equipment. Suitable
radio communication equipment should be
installed whenever practical. Each boat must have
a rope attached to the bow for mooring and
handling, as well as an adequate anchor and suffi –
cient rope for the bottom conditions and depths
expected to be encountered. Auxiliary motive
power and fuel should be on board if at all
8.5.3 Use of taglines
Measuring lines or taglines are frequently used for
measuring the distance across a river. These need to
be of an adequate size and type of material to
prevent stretch and hold the necessary flags.
However, the lighter the cable, the less tension is
necessary in its rigging, and thus handling will be
easier and safer.
Other lines may be rigged to moor the boat at the
desired measurement points, and the same factors
apply. Depending on the current, these may need
to be rather more substantial. All lines must be
fl agged with suffi cient large, brightly-coloured
markers across navigable waters at intervals that
make the line very evident to river users. Colour
itself must not be relied upon, as many people are
colour-blind. Where possible, boats working with
such lines should be equipped with a bright flashing light. Appropriate local authorities and all
likely river users should be notified of the
Such lines may not be left unattended, and
on-site personnel should be equipped with wire
cutters to be used, if necessary, to prevent an
8.5.4 Use of dinghies
In rivers, one should row using the ferry-glide technique, heading diagonally upstream into the
current. The rower is then facing in the direction of
travel downstream, and steerage around any obstacle can be accomplished.
Personnel should be competent at rowing, oars
should be of a suitable length (approximately 1.5
times the width between rowlocks), and secure
rowlocks of the closed type are recommended.
Infl atable dinghies are relatively safe with their
built-in buoyancy. In the event of overturning,
they can be righted by threading the bow rope
around one rowlock, standing on the opposite side
and pulling hard on the rope to overturn it again.
Aluminium dinghies are light and durable. Their
lightness makes them easy to row, but prone to
being blown with the wind, which may make
them unsuitable for windy conditions. If they
become swamped, two people can remove most of
the water by depressing the stern until the bow is
well out of the water and then, quickly raising the
stern, it can then be bailed out by a person alongside. When partly bailed out, boarding can be
accomplished over the stern with a second person
holding the bow down; then the remaining water
can be bailed out. Wooden and fi breglass dinghies
are often too heavy for this technique, but may
fl oat higher when swamped, thus allowing the use
of a bailer.

Before using any cableway, personnel should check
the condition, looking for signs of anchorage movement, changed sag, vandalism or other damage to
the cable, backstays, anchorages, cable hardware
and cable car. Manned cableways normally require
regular inspections and the issuance of a fitness
certificate. The certificate should be current.
Personnel should never board the cable car without
the on-site operator.

When using cable cars, whether moving or stopped,
all personnel must be instructed never to touch the
cable with the hands, because of the danger of being
run over by the cable car wheels. The appropriate
pulling device must be used instead. The maximum
design load of the cableway must not be exceeded,
and wire cutters should be carried to cut the suspension wire if it becomes entangled in the river. The
wire should be cut close to the reel, and personnel
should hold on tightly to the cable car during the
Unmanned cableways generally have powered
or manual winches on the bank, and these
need ratchets and brakes that lock firmly. As
with the use of all winches, long hair and loose
clothing must be fastened back to avoid being
All cables and wires should be installed and used
with due regard for the safety of river traffi c and
aircraft, particularly helicopters. Where appropriate, they must be marked with suitably durable and
visible markers to indicate their presence to operators and pilots.

8.7.1 Surveying
Overhead electrical wires are a hazard when using
survey staves, particularly metal ones. Signs warning of this hazard should be affixed to the back of
staves, at eye level.
8.7.2 Chainsaws
Operators of chainsaws should wear suitable closely
fi tting clothing and safety equipment, including
hard hat, ear protection, eye protection and strong
work boots with steel toe-caps.
The saw should be started while being held on the
ground. Cutting should be carried out in a position
with fi rm footing, clear of obstructions and other
people, and with a safe exit from falling timber or
rolling branches.
Kickback can occur when the chain recoils
upward from striking an obstacle. It can recoil
far faster than a person’s reaction time and may
cause the operator to lose his or her grip.
Lacerated left hands are common in this situation. In order to reduce the likelihood of this
occurring, operators should maintain a firm grip
with a straight wrist and good footing, cut at
peak revolutions, and keep the nose of the bar
away from obstructions.
8.7.3 Electrical equipment
All electrical equipment used outdoors or in damp
conditions must be powered from an isolating
transformer or an earth-leakage current-tripping
device. All electrical leads should be routed to
prevent damage from abrasion and contact with
water. Leads must be kept in good repair, and any
frayed or damaged connections should be properly
Circuits should not be overloaded, and repairs that
should be done by a qualified electrician should not
be attempted.
8.7.4 Power tools
Power tools should be used for their intended
purposes only and always in accordance with
the manufacturer’s specifications. Personnel
should be properly instructed in the use of these
items. The use of some air- or power-operated
tools may require authorization by government
agencies. Safety goggles should always be used
with all cutting, grinding or drilling
8.7.5 Protective clothing and safety
Personnel must be supplied with all safety and
protective items required for the working conditions and equipment being used.
8.7.6 Radioactive equipment
Some items, such as soil-moisture meters and
geophysical instruments, incorporate radioactive
sources. These instruments will be appropriately
marked and must be handled and stored with special care in accordance with the relevant regulations. Radiation emitted by the source can be
hazardous to health. The radioactive material will
usually be sealed within a stainless steel pellet. As
part of the equipment, this pellet will normally be
surrounded by a material such as plastic, steel or
lead, which absorbs radiation. It must be ensured
that the source is within this absorber when the
equipment is not in operation. The pellet must not
be handled under any circumstance. If it needs to
be moved, long-handled tongs or similar equipment must be used.
Keeping a good distance is normally adequate
protection. With some sources, significant exposure
only occurs closer than 10 cm. Others require
considerably more than this. It is imperative that
the personnel determine the type and other details
of the radioactive source being used and that they
acquaint themselves with the recommended procedures and instructions for that source. Where
possible, employers should provide protective gear
to those personnel operating equipment with radioactive devices.
All instructions, procedures and regulations
must be rigorously followed, and the equipment
should be handled with the utmost care at all

8.7.7 Safety aspects of groundwater
In all instances, permission must be sought from
the owners of wells. Pumps and airlift equipment
for sampling, testing or developing wells should be
in accordance with safety procedures for those types
of equipment. Safe practices around drilling rigs are
essential, and manuals of drilling practice should
be consulted.
Entry into large-diameter wells for sampling should
be avoided because of the potential presence of
gases, as described in 8.2.3. Safety harnesses should
be worn when working above large-diameter
8.7.8 Dust menace
Dust results from the inadequate cohesion of
soil particles during a dry period. Dust can
cause excessive wear and tear of equipment,
especially on calibration marks on gauging
instruments. Personnel must ensure that dust is
completely removed from the packing boxes of
these instruments before packing them away
after use.

All chemicals, such as those used for the preservation
of water samples, cleaning fl uids and tracers, must
be stored and handled with care. Inhalation of
vapours or direct contact with skin, eyes and
clothing should be avoided. Any spills must be
cleaned up immediately by dilution with large
quantities of water, neutralization or mopping up
of the chemical followed by disposal of the material.
Gloves, aprons and suitable clean-up materials
should be made available for this purpose.
No pipetting should be done orally, except when
potable waters are the only substance being used.
Skin that has been in contact with acids, bases or
other corrosive substances should be washed
immediately with plenty of water. A neutralizing
solution may be applied if appropriate, to be
followed by a second washing with soap. If any
chemicals enter the eyes, they should be rinsed
immediately with plenty of water. Rinsing around
the eyes should be done as well. It may be necessary to hold the eyelids open during the washing
procedure. Rinsing should continue for several
minutes. All eye injuries must be treated
Precautions must be taken as water may contain a
variety of toxic or bacterial hazardous substances.
These may be derived from a wide range of sources,
such as wastewater or effl uent discharges, leachate
from landfi lls, leakages from storage tanks, washing
of agricultural spray tanks, and chemical or oil
Any unusual appearance, colour, fi lm, frothing,
odours or vapours must be treated as suspicious and
adequate precautions must be taken. Many toxic
substances can enter the body through the skin
and, in the case of vapours, through the lungs.
They can cause eye irritation, skin irritation, pruritus, rashes, nausea, stomach pain, decreased
appetite, headaches, fatigue, coughing, wheezing
and shortness of breath.
Precautions may include gloves, waterproof overalls, aprons, hats and eye protection. Where toxic
vapours might be present, work should only be
carried out in well-ventilated areas or with the use
of self-contained breathing apparatus. Food should
be kept away from samples and sampling locations. Personnel should always wash hands
thoroughly before handling food. Smoking while
sampling or near samples should be prohibited. If flammable compounds are expected to be present,
personnel should keep sparks and heat sources
away, store samples in special explosion-proof
refrigerators and maintain the application temperature of the chemicals.
When measuring or sampling waters with high
concentrations of toxic substances, such as leachate from landfills, or with suspected radioactivity,
special considerations are required and the appropriate specialist should be consulted.

8.9.1 Hypothermia (exposure)
Hypothermia is a condition of lowered body
temperature caused by exposure to cold and results
in rapidly progressing mental and physical collapse.
Its onset is caused by cold temperatures aggravated
by wet clothes, wind, hunger and exhaustion. It
often occurs in conditions where its early symptoms may not be recognized.
Early symptoms of exposure may include signs of
tiredness, cold and exhaustion, lack of interest,
lethargy, clumsiness and stumbling, slurred speech
and irrational behaviour. These signs constitute a
medical emergency and require immediate action
to prevent further heat loss and to effect rewarming. The victim may not complain and possibly
deny that there is a problem. Later symptoms indicating a very serious emergency include obvious
distress, a cessation of shivering despite the cold,
collapse and unconsciousness.
Rewarming must be started immediately when
symptoms become evident. The victim’s body will
probably be incapable of generating sufficient
warmth to accomplish this, and warmth must be
applied gradually to the torso, but not to the limbs
and extremities. Warming the extremities will
increase blood circulation to these cooler parts of
the body and reduce the temperature of the body’s
core still further.
The requirements for rewarming are shelter, dry
clothes, insulation (such as a sleeping bag), and
warmth applied to the vital organs of the body. The
latter can be done through close body contact, for
example, by sharing a sleeping bag. The person
should not be rubbed nor should direct heat be
applied. Warm, sweet drinks, but never alcohol, are
helpful to a person who is conscious.
With warmth and shelter, patients often appear to
recover quickly, but a resumption of cold conditions can bring on collapse. Full recovery can take
up to two days.
Hypothermia can be prevented by providing
adequate shelter and insulated and windproof
clothing. One should avoid prolonged wet conditions and have food and shelter available, such as a
tent or bivouac. Employers and contractors can also
provide warm-up shelters at the workplace where
workers can fi nd refuge from the cold and drink hot
beverages. Warm, sweet drinks and soups are better
than coffee, as coffee increases heat loss from the
When work involves riding on an open vehicle or
some activity that generates wind, the number of
stops should be increased appropriately.
8.9.2 Frostbite
Exposure to extreme cold causes freezing of the
outer parts of exposed tissues, such as toes, ears,
fi ngers and nose. Affected parts become numb, dull
white in colour and waxy in appearance. Superfi cial
frostbite can be treated by applying a hand or
another part of the body to the affected area, without rubbing. Rewarming should not be done by
direct heat or rubbing, or with alcohol. More serious frostbite requires medical treatment.
Prevention involves wearing adequate foot, hand,
face and ear protection, avoiding tight-fi tting clothing or boots, keeping hands and feet dry, and
constantly monitoring for signs of numbness.
Constant movement or wriggling of toes and fi ngers
to stimulate circulation is a short-term remedy that
should be followed to reduce the effect of exposure
to cold.
8.9.3 Working on ice-cold lakes and
Travel and work on ice should be done with great
caution, keeping weight to a minimum. If one falls
through ice, outstretch arms onto solid ice, kick to
keep the body level, crawl forward on the stomach
until hips reach the ice, then make a quick fulllength roll onto the ice. Keep rolling until safe. If
the ice is too thin for support, one should make
one’s way to shore by breaking the ice with one
hand while supporting oneself with the other.
Rescuers should try to reach the victim with a pole,
board or rope. Going out to the ice edge
should only be done as a last resort. If it becomes

necessary, rescuers should carry a long pole or slide
along in a prone position. If there is a rope available, it should be secured to an object on shore. A
person who has fallen through ice must be dried
and rewarmed as soon as possible to prevent
Considerable risk may be involved in taking measurements through ice. Drilling or breaking a hole
may signifi cantly reduce the strength of the ice.
Ice in a stream is likely to be of variable thickness,
and its strength cannot be estimated from its
apparent thickness near the edge. Areas with rapids
or fl ow disturbances, such as bridge piers, are likely
to have thinner ice owing to the water movement.
In advancing across an ice-covered stream, it is
advisable to test the ice with an ice chisel every
few steps. Hard ice will give a resounding ring, and
soft ice will give a dull thud. A safety rope should
be employed when there is any doubt, and a
companion equipped with suitable rescue equipment should be on the bank.
8.9.4 Working in mountainous areas
The weather in mountainous areas can change
rapidly, causing problems for the unwary or illequipped. The colder the climate, the greater the
potential problems and the more clothing, supplies
and safety equipment are required.
Personnel need to be experienced or be with someone who is, and the party’s travel plans should be
known to an appropriate person who could initiate
assistance should this become necessary. Adequate
waterproof, windproof and warm clothing should
be worn and carried, as well as suffi cient food and
survival equipment for the weather extremes.
Ensure that all persons arriving at the site by helicopter have this equipment with them even if they
have been dropped off only for a short time, as
cloud or other weather conditions may prevent the
helicopter’s return.
Venturing out on hard snow is not recommended
without an ice axe, climbing rope and crampons,
and knowledge of their use. It is important to be
wary of avalanches, particularly just after snowfall
or rain, to be aware of the various causes of unstable snow, and to seek advice from experienced
persons. Whatever the snow conditions, travel on
or below steep slopes should be avoided. If caught
in an avalanche, one should make every effort to
stay on top to avoid being buried, cover the nose
and mouth to prevent suffocation and, if buried,
try to make an air space in front of the face and
8.9.5 Cold-water survival
Hypothermia will result very rapidly from immersion in cold water. Its onset can be delayed by
remaining still and having suffi cient coverage of
clothing to reduce water movement against the
body with its accompanying heat loss. It usually
helps to keep as much of the body as possible out
of the water, as the body loses heat much more
quickly to water than to air of the same
It is preferable to keep the head above water and
to draw the legs up in contact with the groin area
to reduce heat loss. A life jacket is invaluable in
assisting with this, and will also provide insulation to the core parts of the body. A number of
people should huddle together, holding on to
each other facing inwards with the sides of the
chest pressed together to reduce heat loss.
Children should be held in the centre of such a
Treatment involves rewarming of the vital organs
of the body prior to warming the limbs and extremities, as described in 8.9.1.

8.10.1 Heatstroke (hyperthermia)
Heatstroke is caused by exposure to high temperature that causes the body temperature to rise
above 40°C. Adverse response to high heat varies
among people depending on their acclimatization, level of fi tness and, most importantly, body
hydration. With the onset of excessive heat, the
body loses heat primarily by the evaporation of
water through sweating and respiration. If this
loss of water is not replenished, the cooling
mechanisms are inhibited and heat builds up.
Symptoms include headache, chilling, nausea,
rapid pulse, muscle pains, loss of coordination
and, more severely, delirium and convulsions. If
not treated, death follows.
Treatment involves immediate cooling by placing
the victim in the shade, removing clothes and
spraying with cold water while fanning vigorously. The victim is given fluids when fully

Table I.8.1. Checklist for vehicle maintenance

Precautions include being physically fit, moderating exercise, drinking moderate amounts regularly and often, avoiding alcohol and
caffeine, avoiding working in the hottest part of
the day, wearing lightweight, light-coloured,
loose-weave clothing and a wide-brimmed hat,
and adding extra salt to meals. Employers can
also use some of the following measures if their
workplaces are very hot:
(a) Engineering controls include using isolation, redesign or substitution to remove heat
sources from work areas, air conditioning to
cool the entire workplace, spot cooling for
hot areas and worksites, local exhaust to
remove heat from workplaces, automation
of hot processes, as well as ensuring that the
maintenance programme quickly fixes problems that create hot conditions such as steam
(b) Fans can increase the airflow and reduce
humidity. Improving the airflow increases the
cooling effect of sweating. However, if the air
temperature is at or above body temperature,
fans will simply expose the body to more hot
air. This increases the heat load and the risk
of heat stress disorders;
(c) Administrative and other measures for
occasional hot indoor and outdoor work
situations include providing regular rest
breaks, providing adequate amounts of drinking water, proper salting of food, training
workers to recognize and treat heat stress
disorders, removing pregnant employees
from hot work areas, scheduling work for
cooler times of the day and providing lightcoloured, lightweight and loose-fi tting cotton
Note: Workers should be strongly encouraged to frequently
drink small amounts of water or other cool (but not cold) fl uids.
One cup of fl uid every 15–20 minutes can replace water lost in
sweat. If workers drink only when they are thirsty, they may not
get enough fl uids.
8.10.2 Sunburn
Excessive exposure to the sun can cause severe
sunburn, particularly to those with fair skin. It
will cause severe pain, damage to the skin and
possibly heatstroke. Prolonged exposure to the
sun’s ultraviolet rays can cause skin cancer, with
fair-skinned people at the greatest risks.
Precautions include wearing protective clothing,
with attention to head covering. Sunscreen
lotions should be applied to the exposed skin.
Exposure to the sun should be confi ned to short
periods each day, with gradual increases to build

Table I.8.2. Checklist for personal protective

8.11.1 General
Modes of travel and transport for hydrological work
are many and varied in accordance with the wide
range of terrain, climate and routes to be covered.
Safety in terms of travel, taking into account all of
the variations of these factors, is a wide topic in
itself and is not confi ned only to hydrological work.
Accordingly, it is only covered briefl y here, and
hydrologists are urged to seek out manuals and
advice for particular local conditions and modes of
8.11.2 Helicopters
On the ground, the noise, wind and urgency
associated with helicopters tend to mask the
dangers presented by the main and tail rotors.
These have killed and maimed many people.
One must not approach or leave the helicopter
without the pilot’s knowledge and approval, and
this should be done within the pilot’s field of
vision. One should approach and leave the
aircraft on the downslope side for maximum
clearance from the main rotor. One should never
walk around the tail.
Personnel should keep away from the landing
pad or zone, and keep it clear of equipment. All
equipment and loose articles should be kept well
out of reach of the effects of rotor wash or they
should be heavily weighted down. Long objects,
such as survey staves, should be carried horizontally at waist level to avoid contact with rotors.
The aircraft should be loaded under the supervision of the pilot, whose attention should be
drawn to hazardous cargo, such as batteries and
Cableways and aerial wires are particularly hazardous to helicopter operations, and personnel should
make the pilot aware of any that are known and
assist in looking out for others.
8.11.3 Motor vehicles
In much hydrological work, frequent travel by
motor vehicle means potential for serious accidents.
Travel on remote, backcountry roads is common,
and this provides additional hazards to those that
can be encountered on highways.
The most common causes of accidents relate to
excessive speed. This is no less true of backcountry
roads, which are often narrow and winding and

have loose surfaces. The best drivers tend to accelerate smoothly, corner carefully and brake gently,
being considerate of their vehicle, their passengers
and other road users.
Keeping a vehicle in good working order
helps to maintain control in adverse driving conditions. Table I.8.1 provides a checklist for vehicle

Personnel in remote areas should carry emergency
survival kits. The components of these kits will vary
greatly depending on the climate, conditions and
mode of travel, but should include long-life emergency food, water, water purification tablets or
iodine, cooking and heating equipment, shelter,
such as a tent or bivouac, sleeping bags, lighting,
medical supplies, adequate clothing for the worst
possible conditions, toiletry items and signalling
equipment, such as a mirror, flares, walkie-talkies,
mobile phones and two-way radio. A checklist
for personal protective equipment is provided in
Table I.8.2.
First-aid training should be given to all field personnel, and each person should be supplied with an
adequate first-aid kit and manual. Topics to be
covered should include rescue breathing, cardiopulmonary resuscitation, unconsciousness,
bleeding, fractures, shock, eye injuries, poisoning
and burns.
Personnel should check their emergency preparedness planning at least once every six months.
This will enable them to update their survival

Field personnel should be familiar with, and always
be on the lookout for, other hazards posed by their
working environment. These include poisonous
plants, stinging or biting insects, dangerous animals,
quicksand and electrical storms. Also, bodily contact
with or ingestion of some waters may pose signifi –
cant health risks. In some localities, there may be
possibility of attack by other people, for example,
those who may be engaged in illegal activities.
Employers have a responsibility to ensure that their
employees are never unknowingly exposed to any
such risks.
In case of remote fi eld activities, personnel should
travel with at least one local person who is familiar
with most of the routes, people and the security
situation. Some effort should be devoted to informing local leaders about the activities to be carried
out in their area. This will increase community
participation and cooperation.
References and further reading
Brassington, R., 1998: Field Hydrogeology. Second edition,
Wiley, Chichester.
Corbett, P., 1986: Hydrographers fi eld safety manual
(draft). Report No. T.S. 89.002, Department of Water
Resources, New South Wales Government.
Curry, R.J. and J.K. Fenwick, 1984: Hydrologists’ Safety
Manual. Water and Soil Miscellaneous Publication
No. 64, National Water and Soil Conservation
Organisation, Wellington.
Environment Canada, 1983: Sampling for Water Quality.
Water Quality Branch, Inland Waters Directorate,
Environment Canada, Ottawa.
Herschy, R.W., 1998: Hydrometry: Principles and Practice.
Second edition, Wiley, Chichester.
Lane, S.L. and R.G. Fay, 1997: National Field Manual: Safety
in Field Activities. Book 9, Chapter A9, United States
Geological Survey, Reston, Virginia (http://water.usgs.
United States Geological Survey, 1989: Environmental
Compliance and Protection Handbook. 445-1-H,
Reston, Virginia (http://www.usgs.gov/usgs-manual/
United States Geological Survey, 2001: Occupational
Safety and Health Program Requirements Handbook.
445-2-H, Reston, Virginia (http://www.usgs.
Yobbi, D.K., T.H. Yorke and R.T. Mycyk, 1995: A Guide to
Safe Field Operations. United States Geological Survey
Open-File Report 95-777, Reston, Virginia (http://