What is DAM?
A dam is a barrier that impounds water or underground
streams. The reservoirs created by dams not only
suppress floods but provide water for various needs to
include irrigation, human consumption, industrial use,
aquaculture and navigability. Hydropower is often used
in conjunction with dams to generate electricity. A dam
can also be used to collect water or for storage of water
which can be evenly distributed between locations. Dams
generally serve the primary purpose of retaining water,
while other structures such as floodgates or levees (also
known as dikes) are used to manage or prevent water
flow into specific land regions.
Should SAFETY MANAGEMENT be implemented
during DAM CONSTRUCTION? OF COURSE
DURING THE HOOVER DAM CONSTRUCTION
There were 112 deaths associated with the construction of the dam.
The first was J. G. Tierney, a surveyor who drowned on December 20,
1922, while looking for an ideal spot for the dam. His son, Patrick W.
Tierney, was the last man to die working on the dam, 13 years to the day
later. Ninety-six of the deaths occurred during construction at the site.Of
the 112 fatalities, 91 were Six Companies employees, three were BOR
employees, and one was a visitor to the site, with the remainder
employees of various contractors not part of Six Companies.
Not included in the official fatalities number were deaths that were
recorded as pneumonia. Workers alleged that this diagnosis was a cover
for death from carbon monoxide poisoning, brought on by the use of
gasoline-fueled vehicles in the diversion tunnels, and a classification used
by Six Companies to avoid paying compensation claims. The site's
diversion tunnels frequently reached 140 °F (60 °C), enveloped in thick
plumes of vehicle exhaust gases. A total of 42 workers were recorded as
having died from pneumonia; none were listed as having died from
carbon monoxide poisoning. No deaths of non-workers from pneumonia
were recorded in Boulder City during the construction period.
Roles and Responsibilities
responsible for having a safety management plan in place
and for assuring safety on site, the safe and healthful
performance of their work, preventing accidents or damage to
adjacent public and private property, and safety training of
their employees. When a contractor is advised by the Agency
of a safety violation, the contractor should respond in writing
and immediately take corrective action as set out in their
safety management plan.
enforce safety by developing a Job Hazard Analysis for the
work to be undertaken and discussing actions needed to
provide safety at jobsite planning meetings. Supervisors draw
on their safety experience to direct the actions of those under
their direction. Contractor staff should include a safety
professional who undertakes surveillance of operations to
eliminate sources of potential accidents.
give newly employed, promoted, and/or transferred
personnel comprehensive safety indoctrination on topics such as:
workplace hazards, required protective equipment, procedures for
reporting unsafe job conditions, procedures for reporting
accidents, contractor job rules, location of first-aid and medical
facilities, and tool box safety meeting requirements. Safety should
be a standing item at site meetings. Foremen or shift supervisors
should also hold regular crew training (toolbox) meetings to cover
specific safety procedures pertinent to the crew’s on-going activity.
should display signs and posters at the job site to reinforce
Accidents should be investigated without delay by the
contractor and the investigation should generate
recommendations for corrective actions to prevent recurrence of
similar accidents. The contractor’s accident report, project
records, progress reports, and daily time reports may become
important evidential material in any ensuing legal action. The
contractor prepares monthly accident summary reports for
submission to the CM. These reports will allow the CM to assess
contractor safety performance as measured by recordable and lost
time accident frequency rates and the type and cause of accidents.
The federal and state regulations mandate reporting of certain
injury accidents to the authorities.
• PERMIT HOLDER
to ensure that the site which is chosen
for the dam is well clear of all easements,
rights of way, reserves, and for all purposes
such as access, pipelines, cables, power lines.
Where property of neighbors will be affected
by a dam, the permit holder will need to make
all necessary arrangements with the
to ensure that no utilities such as
electricity, natural gas, water and sewage
infrastructure can be damaged during the
construction of their dam. It can be a very
expensive exercise to have these repaired and
the permit holder is generally responsible.
• Best to have designer involved in
Present key aspects of the design, critical
issues. Helps to focus site staff on the key
Designer to have at least annual review of
performance – field inspection and review
• All personnel that will be in vicinity of
facility should be trained to identify
conditions that could lead to failure
• All personnel should know how to
report a potential problem
JOB SITE INSPECTIONS
1. Removing the hazard.
2. Guarding against the hazard as required.
3. Providing personal protective equipment and enforcing its
4. Training workers in safe work practices.
5. Coordinating protection of workers through other
Common Causes of Dam Construction Site Accidents
Fires and Explosions
Because of unfinished piping, leaking gases, and incomplete electrical systems,
fires and explosions are a common occurrence on construction sites.
Slips and Trips on Scaffoldings
Construction workers may slip on a wet patch or trip over a cable . • Can lead
to many different injuries and ill health outcomes, from musculoskeletal
disorders (e.g. strained ankle) to puncture wounds (from falling on sharp
Fall from Height
According to OSHA, fall accidents are the number one cause of construction
site fatalities, causing 36 percent of all construction worksite deaths in 2012.
Falls are often the result of: • Failure to properly install scaffolding, • Failure
to use proper safety gear, • Inappropriate use of inappropriate ladders and
Falling Debris (e.g. rocks)
All accidents resulting in injury or property damage will be investigated. The purpose of
the investigation is NOT to find fault, but to find the cause of the accident so similar
incidents can be prevented in the future.
1. All accidents, no matter how minor must be reported to the Foreman immediately.
2. Foremen must report all accidents to the Safety Coordinator as soon as possible.
3. Foremen must complete an initial written accident investigation the day of the
accident, if possible.
4. All workers involved in the accident or who witnessed the accident must complete a
written statement describing the incident.
5. The Safety Coordinator will complete a thorough accident investigation to determine
root causes and corrective actions.
6. Near misses (situations where an accident almost happened) should be reported.
Corrective action must be taken to prevent the same situation from occurring again
with the potential for serious injury. Foremen should make a note of near misses and
the corrective actions taken and report them to the Safety Coordinator, so that the
same corrections may be made on all the company’s job sites.
Compliance with the design intent during the implementation of a scheme is essential for
dam safety and ongoing involvement of the designer in the construction, either as an
adviser, reviewer or resident staff is highly desirable and has not always occurred in the
past leading to dam safety incidents, failures or potential deficiencies where the designers
intent has not been fulfilled in the construction of the structure. There is always the
danger in believing that the design report, specifications and drawings can fully impart
the understanding and design intent of the designers, whose role is often curtailed at the
completion of these documents.
Construction is a critical phase in achieving a safe dam. Any project must be continuously
evaluated, and "re-engineered" as required, during construction to assure that the final
design is compatible with conditions encountered during construction. Quality of
construction is also critical to safety. Deficiencies in materials or construction practices
can occur during all stages of the construction, and constant vigilance is necessary to
prevent them. Sampling and testing at a completed project cannot be relied on as an
effective substitute for inspection and quality control during construction.
MAINTENANCE AND INSPECTIONS
Once the dam has been constructed, regular maintenance and
inspections are required to ensure it remains in a good
Dams over 10 meters in height and dams with hazard
categories of ‘Significant’ and higher require the following
regular inspections to be carried out:
• Weekly or more frequent inspection to be carried out by the
• Biennial or intermediate inspections and surveillance
reports carried out by a suitably qualified person (as
defined by the Water Management (Safety of Dams ) 2003
• Comprehensive surveillance reports carried out every 5
years by a suitably qualified person such as a Class A
competent Engineer as defined by the Water Management
(Safety of Dams ) 2003 Regulations.
The maintenance and inspection requirements detailed above do not always apply to
Lower hazard category dams. In such cases the dam owner should read their dam permit
to verify what maintenance and inspection requirements must be undertaken.
It is good practice for the dam owner to inspect their dam on a regular basis to ensure
that the dam is operating in a safe manner. Such inspections should include the
following as well as any other matters the dam owner thinks necessary to inspect:
• Inspection of the spillway to ensure it is not blocked by logs or trees growing in the
spillway or deliberately blocked to increase the capacity of the dam (section 3.16
provides information on spillways);
• Inspection to ensure that trees have not become established on or near a dam
embankment. Tree roots can cause the embankment to crack leading to dam stability
problems (section 3.15 provides information on vegetation). The highest plant growth
that should be allowed on a dam embankment is pasture grass to protect against
• Seepage from the dam should be monitored on a regular basis. Seepage is generally
normal in all dams and should not be a concern unless it increases over a time or the
water becomes turbid (dirty). An increase in turbid water is an indication that the
embankment may be eroding internally which may lead to piping failure. If concerned,
a suitably qualified and experienced person should be consulted.
It is suggested that the dam owner use a logbook to record observations from any dam
maintenance and inspections visits for future reference.