1. ------IND- 2011 0134 RO- EN- ------ 20110418 --- --- PROJET
GOVERNMENT OF ROMANIA
MINISTRY OF REGIONAL
DEVELOPMENT AND TOURISM
No………from the date of ………2011
for approval of the technical regulation
“Guide to equipping hydraulic retention structures with
measurement and control devices – MCD”, code GT 064:2011
In accordance with the provisions of Article 10 and Article 38(2) of Law No 10/1995 regarding
quality in construction, with its subsequent modifications, the provisions of Article 2(3) and (4) of the
Rules regarding the types of technical regulations and costs for regulatory activity in the field of
construction, town planning, landscaping and habitat, approved by Government Decision No 203/2003,
with its subsequent modifications and supplementation, and the provisions of Government Decision No
1016/2004 regarding measures for organising and carrying out the exchange of information in the field of
technical standards and regulations, as well as the rules regarding information society services between
Romania and the EU Member States, as well as the European Commission, with the subsequent
taking into consideration Approval report No 6/25.10.2010 of Specialist Technical Committee No
7-Hydrotechnical and Hydro-municipal Construction within the Ministry of Regional Development and
on the grounds of Article 5(II)(e) and Article 13(6) of Government Decision No 1631/2009
concerning the organisation and operation of the Ministry of Regional Development and Tourism, with its
subsequent modifications and supplementation,
the Ministry of Regional Development and Tourism hereby issues the following
Article 1 – The technical regulation “Guide to equipping hydraulic retention structures with
measurement and control devices -MCD, code GT 064:2011”, drawn up by the Technical University of
Civil Engineering of Bucharest and stipulated in the appendix*) which is an integrated part of the present
Order, is hereby approved.
Article 2 - The present Order shall be published in the Official Gazette of Romania, Part I, and
shall come into force 30 days after its date of publication.
The present order was adopted in accordance with the notification procedure stipulated by Directive
98/34/EC of the European Parliament and of the Council of 22 June 1998, laying down a procedure for the
exchange of information in the field of technical standards and regulations, published in the Official
Journal of the European Communities L 204 from 21 July 1998, amended by Directive 98/48/EC of the
European Parliament and the Council, published in the Official Journal of the European Communities L
217 from 05 August 1998.
Elena Gabriela UDREA
*) The Order and its appendix shall also be published in the Construction Journal edited by the National Institute for Research and
Development in Construction, Town Planning and Sustainable Regional Development "URBAN-INCERC", coordinated by the Ministry of
Regional Development and Tourism.
GUIDE TO EQUIPPING HYDRAULIC RETENTION
STRUCTURES WITH MEASUREMENT AND CONTROL
DEVICES – MCD,
code GT 064:2011
Prepared by: Technical University of Civil Engineering of Bucharest
Terminology and abbreviations
1. Principles for equipping with MCDs
1.1 The importance of monitoring the behaviour of hydro-technical retention constructions
1.2 Monitored parameters and specific equipment for dams made of concrete and filler materials
2. Enforceable requirements for the monitoring system
2.1 General aspects
2.2 Example of equipping a concrete dam
2.3 Example of equipping a dam made of filler materials
2.4 Primary operational processing of the measurements. Behaviour models for diagnosing the
safety of the construction.
3. Special tracking design
3.1 General data and content of the design
3.2 Frequency of measurements
3.3 Content of annual reports and summarising reports relating to the behaviour of the structure
4. Behaviour models
4.1 General aspects
4.2 Deterministic models
4.3 Statistical models
4.4 Models based on neural networks
4.5 Other models
5. Information flow
Appendix 1 - Reference documents
1. DAMAGE: any degradation (deterioration) or consequence of an event, which has a harmful
(unfavourable) effect on the physical state of a product or structure, or on a part or component of
In construction, there are two main categories of damage:
a) structural damage to the elements or joints of the supporting frame of a structure.
b) non-structural damage to the elements or parts of a structure which are not part of its
2. LOG BOOK OF THE STRUCTURE: The set of technical documents relating to the design,
execution, acceptance, operation and behaviour tracking of the structure during operation, which
includes all the data, documents and records needed in order to identify and determine the
technical (physical) condition of the structure and its development over time.
3. THE IMPORTANCE CATEGORY OF STRUCTURES: a category established based on a
group of factors and related criteria, which enables the people involved in the process of building
certain structures and their entire life cycle to perform a differentiated assessment for these
structures depending on their characteristics and relationship with the human, socio-economic and
1) Establishing the importance category of structures is required for the differentiated application
of the quality system and all of its components, especially the quality assurance and management
system, as well as other legal provisions.
2) The importance categories of structures are:
a) global importance categories, usually called “importance categories”, which refer to all
aspects of a structure.
b) specific importance categories, called “importance classes”, which only refer to certain
aspects of structures or some of their parts.
4. IMPORTANCE CLASS: a specific importance category which refers to certain defined aspects of a
structure or some of its parts.
5. OPERATIONAL BEHAVIOUR (behaviour over time): manifestation of the way a product
(structure) reacts (in all of its properties and characteristics) to the requirements with regard to its
operational ability, during its service life.
1) In the performance approach, the operational behaviour of a product shall be assessed by the extent
to which its performance meets the specified requirements.
2) The operational behaviour of a product reflects its durability, namely its ability to perform over
6. MEASURING EQUIPMENT: apparatus, device (instrument, means) intended to be used,
independently or in combination with other devices, in order to carry out measurements of a given
Measuring equipment (instrument, device) can be used individually or as part of complex systems
a) Measurement systems, consisting of complete measurement instruments and other devices,
used to carry out the specified measurement operations;Measuring and testing equipment,
designed to carry out testing and measurement operations in order to obtain information
about the characteristics of a product.
7. EXPERT: a person certified by a state authority to carry out an expert survey in a given domain
8. TECHNICAL SURVEY: a survey carried out by a certified technical expert or specialist institute
on a situation or problem related to the quality of a construction product, service, design or works,
as well as the technical condition of existing structures.
9. INSPECTION: the verification, inspection or supervision activities carried out as part of a given
10. EVENTS DIARY: a document that is part of the log book of a structure, in which all the events
(deeds, actions, activities, interventions, checks, expert surveys, inspections, etc.) that occur
throughout the lifespan of the respective structure are recorded in chronological order, along with
the results and effects that these events have on the structure.
11. MEASUREMENT METHOD: the set of theoretical and practical operations, in general terms,
applied in order to carry out measurements based on a given principle.
12. TESTING PROGRAMME: a technical document drawn up in order to define the object and set
of conditions and activities that must be met/carried out in order to comply with the specified
requirements of a given test.
In general, a testing programme must specify the following:
a) the characteristics that must be determined by testing;
b) the number or quantity of the products being tested;
c) the standardised testing methods that must be used or, in their absence, a short description
of the test;the order in which the operations must be carried out;the way in which the
results must be presented.
13 TEST REPORT: a document that presents the results of a test and other relevant information
relating to the test.
Other terms can be used to name this document, such as: report about testing or testing report.
14. MEASUREMENT SYSTEM: a complete set of measurement instruments and other devices used
to carry out the specified measuring operation (works).
15. TRACKING THE (OPERATIONAL) BEHAVIOUR OF STRUCTURES: a systematic
manner of tracking, examining and investigating the way structures behave (react) during
operation under the action of environmental agents, operating conditions and activities carried out
by their users.
MCD – Measurement and control devices
ICOLD – International Commission on Large Dams
MLPAT – Ministry of Public Works and Land Development
PV – Report
SGA – Water Management System
UCC – Tracking the behaviour of structures during operation/over time
UCCH – Tracking the behaviour of hydraulic structures
1. PRINCIPLES FOR EQUIPPING WITH MCDs
1.1. The importance of monitoring the behaviour of hydraulic retention structures
(1) Dams are structures with a very long lifespan, and building them requires significant investment.
Monitoring their behaviour during construction, when they are first set into operation and throughout their
entire operation guarantees their safety and prevents any accidents that could become catastrophes .
(2) The information obtained by monitoring dams helps determine the best times to carry out
regular maintenance works. It also helps identify any potential atypical behaviour phenomena from an
early stage so appropriate measures may be taken before such phenomena threaten the safety of the
(3) Monitoring the behaviour of dams shall be done by qualified personnel who carry out visual
inspections and interpret data obtained by monitoring the behaviour of the relevant parameters using
measurement devices. Currently, general opinion is that a monitoring system, however complete and
sophisticated it may be, cannot replace a direct visual inspection. Some of the most dangerous events, such
as local deformations, cracks, concentrated infiltrations or wet patches cannot be detected using
measurement instruments. However, once an anomaly has been detected during visual inspections through
the monitoring system, its development can be monitored and interpreted on the basis of the data provided
by the monitoring system.
(4) Dam safety has always been a concern for the specialised committees within ICOLD. Over
time, various statistics have been determined regarding dam incidents or failures, the investigation
concentrating on the causes of these incidents and the failure rate as a function of the type, age, height or
total number of dams.
(5) Such research, which aims to reduce the number of dam incidents and failures, is fully justified
if we take into account the fact that failure of a dam can cause damages that are tens of times more
expensive than the cost of the structure and, even worse, can claim many human lives. The progress made
in relation to design concepts, building technologies and operational behaviour monitoring have led to a
constant drop in the dam incident and failure rate over time. At the same time, hazard alarm systems were
developed for the population located downstream from any dams, which have proven useful on many
occasions, and dam safety assurance systems for unforeseen situations are currently being implemented
, , , , , , , .
(6) The ICOLD Committee for dam failure statistical analysis also redefined the terminology in the
field so that it can be uniformly applied in all ICOLD Member Countries.
(7) Dam failure is understood as the breaking or displacement of a part of a dam or its foundation,
so that the dam can no longer retain water. In general, a rupture leads to the discharge of large,
uncontrolled water quantities, which poses a risk to humans and property (assets) located downstream
from the dam.
(8) The occurrence of an event that caused the partial or complete destruction of a dam during
construction is considered to be a “failure” if a large volume of water was discharged involuntarily, after
the dam reached a height that enabled an upstream accumulation of water at least 15 m deep.
(9) The incident category includes all other situations that cause damage, including accidents that
caused deterioration, damage or operating malfunctions of the dam, but without causing it to rupture.
(10) Depending on the age of the dam, statistical processing has shown that 70 % of dam failures
occurred in dams younger than 10 years. Of these failures, more than 50 % occurred during building of the
dam, its first filling with water or immediately after the first filling.
(11) Analysis of dam failure as a function of dam height has shown that 60 % of all catastrophic
failures resulting in more than 100 human victims occurred in dams with heights H < 30 m. It appears that
the monitoring and maintenance of these large dams with a relatively small height are not carried out with
the same thoroughness as for taller dams.
(12) The dam failure rate (dam/number of years of operation) before 1990 was above 4 %. The
failure rate decreased over time, especially after the 1950s, and is currently below 0.5 %. The
technological progress registered during this period, improvement of the design, execution, monitoring
and maintenance methods, as well as experience accumulated by analysing all failures or incidents have
significantly contributed to the continuous decrease in the failure rate.
(13) Figure 1.1 shows the failure statistics as a function of the type and height of the dams. The
conclusion that can be drawn from this figure is that the failure rate of dams made of filler materials,
especially earthfill dams, is higher than the failure rate of concrete dams. In relation to the total number of
existing dams of a certain type, the lowest failure rate was registered for arched dams.
(14) The most frequent causes for the failure of dams made of filler materials are, in order of their
frequency: overflowing mainly due to underestimating design for flash floods, internal erosion, and
structural instability caused primarily by seismic action.
In concrete dams, the main causes of dam failure were excessive stress, or instability of the
foundation or shoulders of the dams
(15) Most incidents and failures that occurred during the building process were caused by one or
more of the following:
undersized temporary bypass or a flash flood that exceeded the design value;
unforeseen delays in building the structure.
TE – earthfill dams
ER – rockfill dams
PG – gravity dams
CB – buttress dams
VA – arched dams
MV – multi-arch dams
Number of cases
TCTA TE/ER PG CB VA MV special
Type of dam
h < 30m 30 < h < 60m 60 < h < 100m
Fig. 1.1. Number of failures per dam type and height (TE/ER – earthfill/rockfill, PG – gravity, CB –
buttress, VA – arched, MV – multiple-arch).
(16) Most often, design errors arise from inadequate operation of calculation programmes by
inexperienced engineers or engineers lacking enough experience in using the respective calculation
(17) Serious errors could also occur due to insufficient on-site investigation or laboratory testing,
or due to the incorrect interpretation of test results. Design hypotheses based on incorrect estimations of
the properties of the materials used in the dam-foundation assembly can easily lead to severe
(18) Permanent communication between the building contractor and the design team is essential in
adapting the design to new conditions that may appear during execution and avoiding potentially severe
(19) The most frequent structural faults appear due to works of unsatisfactory quality being carried
out, which are improperly monitored. Building works specific to dams require that the building contractor
has certain experience in carrying out such works, which could be missing in countries where dam
building activities are just beginning.
(20) Flash floods occurring while building dams were the direct or indirect cause of numerous
incidents or failures. The issue of sizing temporary bypass works for flash flooding must be resolved on
technico-economical bases, comparing the additional costs required by a higher level of safety against
flooding of the structure to the potential damage caused by such flooding. The contractor’s strict
compliance with the calendar execution schedule, which takes into account the seasonal variations of
natural phenomena – drought periods, rainy periods, etc. – is of maximum importance in reducing the risk
of incidents or failure due to flash flooding.
(21) The first filling of the reservoir is an operation of vital importance. The level of water in the
reservoir should be increased gradually, at the lowest possible, controllable rate, using elevated planes at
certain levels and careful monitoring of its structural behaviour. Detailed inspections of the dam,
foundation and shoulders, as well as discharge-dissipation works must be carried out once each filling
stage is complete. Also, the banks of the reservoir must be inspected for any possible instability.
(22) Serious incidents and failure could occur during the first filling or in the period immediately
after the first filling. These are most likely caused by deficiencies in the investigations carried out in order
to provide the necessary data for the design or execution stage. In the past, however, these were
sometimes caused by unpredictable phenomena, such as major landslides or seismicity induced by the
(23) The slightest signs of deficiency or unforeseen behaviour must be carefully monitored and
interpreted so that any potentially dangerous phenomena can be discovered promptly and prevented.
Rigorous monitoring, as well as frequent visual inspections, must be carried out for at least one year – i.e.
throughout the duration of a full annual hydrological cycle – after the reservoir has reached its maximum
level for the first time.
(24) The drainage systems and the behaviour of the foundation and shoulders of the dam shall be
especially monitored. The occurrence of excessive or uncontrollable (especially concentrated) infiltrations
is always a serious sign of hazard, which could be caused by deficiencies below the retention level or the
dam body level. All types of dams made of filler materials are vulnerable to this hazard, but the stability of
gravity structures can also be severely affected by the occurrence of excessive underpressure.
(25) Instability of earthfill dam gradients can be the consequence of insufficient compaction but,
when such instability occurs during the first filling or first drainage, it is more likely to be the result of
incorrect design hypotheses. Differentiated settling or deformation of the foundation is the consequence of
inappropriate interpretation of compressibility tests carried out on the filler materials, or insufficient
investigations of the foundation. Major differentiated deformations during or immediately after the first
filling of the reservoir are a sign of structural weakness and will undoubtedly lead to cracking. Any pipes
that go through the dam body, as well as any drainage systems consisting of tubes, must be designed and
installed by paying particular attention to the risk of causing differentiated settling. Any exfiltration from
such pipes or drainage systems can severely affect the stability of the filling.
(26) Most of the incidents and failures occurring during dam operation are directly or indirectly
caused by human errors, including the absence or insufficiency of everyday precautionary measures, as
well as appropriate monitoring and maintenance. The same category includes any intentional or
unintentional changes to any constructive details on site, without the consent of the design engineer.
(27) Any deviation from the operating instructions, even if it is unintentional, can have extremely
serious consequences. For example, non-compliance with the operating instructions for overflow
spillways can easily compromise the safety of the dam and its related structures.
(28) Systematic monitoring and visual inspections represent the best protection against incidents or
failure. The primary information provided by the measurement and control devices must be immediately
sent to the persons responsible for the safety of the dam, so that it can be processed and interpreted.
(29) Approximately 65 % of dam failures occurring during operation were caused by insufficient
capacity of the spillways. These spillways were sized for flash floods assessed using inappropriate criteria
or methods, or their insufficient capacity was due to changes in the flow conditions present in the river
basin upstream from the dam. Dam overflowing can also be caused by the non-operability of the sluice
gates that enable access to the overflow fields (sluice gates blocked in the closed position, power cut-offs,
freezing, overflow fields blocked by floats, etc.). Clogging of the reservoirs can also reduce the storage
capacity of the reservoirs and their capacity to alleviate flash flooding.
(30) Gradual clogging of the drains can be particularly dangerous for the stability of the dam due
to an excessive increase of underpressure, or of the pore water pressure. An increase in infiltration can
especially affect the safety of earthfill dams by creating internal erosion phenomena. Continuous
infiltrations that go through or bypass an earthfill dam threaten to damage the foundation and shoulders of
the dam by reducing slip or shear resistance, even after many years of operation under apparently normal
(31) Finally, using the maximum installed capacity of the spillways can cause catastrophic flash
floods downstream from the dam, even larger than those occurring naturally. In the event of a large-scale
flash flood, the operating personnel must often solve the terrible dilemma of whether to cause flooding
downstream from the dam, with all its associated consequences (damage of goods and, potentially, loss of
human lives), or limit the volumes of water being discharged, which would endanger the safety of the
1.2 Monitored parameters and specific equipment for dams made of concrete and filler
(1) Monitored parameters can be grouped into two categories: environmental actions and physical
variables which describe the response of the dam-foundation system to environmental actions. The main
parameters from the first category are: the level of water inside the reservoir, air temperature, water
temperature at various depths of the reservoir, solar radiation, seismic movements. The monitored
physical parameters which describe the response of the dam-foundation system shall be differentiated
depending on the type of the dam. For concrete dams, the following parameters can be mentioned:
absolute displacements of the dam and foundation, relative displacements between the blocks, temperature
development within the dam body, the level of deformation and stress in the dam and foundation, the level
of cracking, interstitial pressures and under-pressures, infiltration rates. For dams made of filler materials,
the main response parameters being monitored are: displacements, especially settling of the dam-
foundation system during the building and operation stages, infiltrations and the position of the infiltration
curve, pore water pressure in the earth elements and sealing elements, the actual and total stresses,
infiltrations in the slopes, displacement of the slopes, the level of deformation and stress in the concrete
structures associated with a dam made of filler materials (surface spillways, bottom discharges, etc.).
(2) Table 1.1 gives a summary of the main parameters that need to be monitored, grouped for
concrete dams, dams made of filler materials, and dam foundation rock massifs. The monitoring
equipment must be sufficiently numerous and extended so that, in the event of abnormal behaviour, the
causes can be established based on recorded data and on-site inspections. In such situations, it may be
necessary to install additional monitoring devices.
Concrete dams Dams made of filler Foundations
Structural deformations Deformations of the dam Deformations
Special displacements body Displacement of the slopes
(cracks, joints) Special displacements during dam springing
Dam body temperature (connections to concrete Special displacements
Under-pressures (on the structures) (cracks, faults)
dam/foundation contact Detecting any infiltrations Detecting any infiltrations
surface and in the rock) by measuring the dam body by measuring the dam body
Infiltration and drainage temperature (possible) temperature (possible)
rates Pore pressure in the body of Pore pressure (in hard rock,
Chemical analysis of a dam made of filler the interstitial pressure)
infiltrated water materials, and the Piezometric level
Turbidity (possible) piezometric level. Underground water level
Infiltration and drainage Infiltration and drainage
rates. volumes, and their sources
Chemical analysis of Chemical analysis of
infiltrated water infiltrated water
(3) The instruments and systems used to measure the above mentioned parameters have evolved a
great deal over time. If mechanical or electrical devices for in situ measurement were used during the
period between the two world wars and in the first decades after the Second World War, automatic
monitoring systems are currently used on an increasingly wider scale, which can send data remotely to
data collection, processing and interpretation centres. Electronics and computer science have become
predominant, especially in the field of data transmission and processing. To send data between territorial
units and the central unit, transmissions via radio, fibre optic cables, mobile telephone networks and the
Internet are currently used instead of traditional telephone lines.
(4) Fibre optic sensors have numerous optical properties obtained from the light that goes through
the fibre optic, which can be modified by certain actions such as: pressure, stress or temperature that act
upon the fibre.
(5) The main advantages of fibre optic sensors are the following:
they are immune to electromagnetic interference: being ideal in microwave environments;they are
resistant to high temperatures and reactive chemical environments: being ideal for hostile and
severe environments;they have small, even miniscule dimensions: ideal for encapsulation or
installation on a surface;they can measure a wide range of physical and chemical parameters;
they have the potential for measurements with very good characteristics of precision, sensitivity
and range;they have full electrical insulation against high electrostatic potential (electric
discharges);they can be operated from very long distances that can be measured in km, without any
significant losses of the measured signal: they pose an advantage for measurements carried out
over large lengths (weirs, slopes) or hazardous environments;multiplexed sensors and distributed
sensors are unique since they supply measurements at a large number of points along the same
fibre optic cable: ideal for minimising the length or weight of a fibre optic cable, monitoring very
long dams or weirs, or buried water supply pipes.(6) Optic fibres are long fibres of very pure glass
with the diameter of a human hair. They are bunched together in bundles called optic cables and
are used to transmit luminous signals over long distances.
(7) The components of a fibre optic cable are as follows (fig. 1.2):
core – centre of the fibre, made of glass, that light circulates through;
cladding – optical material which covers the core and fully reflects light;
protective jacket – plastic coating made of acrylic material, which protects the fibre against
scratching and moisture;
jacket made of polyamide material (optional), used to increase protection of the fibre at
temperatures of up to 300 °C;
a buffer layer made of light plastic material;
Kevlar reinforcement fibres are added to increase the mechanical resistance of the cable to
approximately 200 kgf;
the last layer is a polyurethane outer jacket that provides protection against the outside
Core Cladding Protective Reinforcement Outer jacket
Optical Optical fibre
250 Micron 125 Micron cladding
4mm 2mm 1mm
Mechanical protection - Kevlar
Fig. 1.2. Structure of an optical fibre
(8) Figure 1.3 presents the typical diagram of an automatic monitoring system, in the form of a
chain. The parameters are measured using sensors (transducers). The main quality of the sensors is their
reliability, taking into account that, in many cases, they are impossible to replace since they are embedded
in the body or foundation of the dam. Instruments used to measure the deformations (stresses) based on
the vibrating chord principle, for example, have proved their reliability, since there are structures in which
they have been operational for more than 50 years. Sensors with electric transmission are used more and
more frequently because they can be easily adapted to an automatic monitoring system.
Amplifier Filter Computer
Parameter to Transducer Analogue – digital (data Analysis
be measured signal converter acquisition and
Fig. 1.3. Typical diagram of an automatic monitoring system in the form of a chain.
(9) Table 1.2 contains data about the measurement instruments and equipment, as well as the
methods used to measure various parameters that monitor the behaviour of retention structures, including
their surrounding environment.
(10) Column 1 in the table contains the measurement parameters that play a decisive role in the
behaviour of concrete dams and dams made of filler materials, grouped according to the nature of their
stresses and reactions.
(11) Column 2 contains the most appropriate and used monitoring instruments and equipment, as
well as the measurement methods used for the parameters mentioned in column 1.
(12) Column 3, “Requirements”, refers to the conditions that the measurement
instruments/methods used must meet, as follows:
F – Very high reliability, required for instruments that provide data that are indispensable in
characterising the behaviour of the dam and must be available at all times.
L – Longevity is important for those instruments that measure important data, and must be
associated with sufficient redundancies. The replacement of some parts of the equipment or the correlation
with previous measurements should not cause large delays or situations of difficulty.
M – The measurement range must be sufficiently wide to cover exceptional loads or unexpected
P – The precision required must embed all the errors of the instrument and measurement procedure
(inaccuracy of the instrument and its calibration, the influence of temperature, covering material, friction,
wear and tear, deviations from point 0, non-linearity, etc.).
R – Redundancy means both doubling (independently) of a measurement instrument, as well as the
possibility to check or repeat a measurement using another measurement device (instrument).
(13) Column 5, “Comments”, includes important details or instructions, or the characteristics of
the parameter being measured or instrument being used.
Parameter measured Equipment Requirements
Measurement system F – durability
Measurement method (reliability)
L – longevity Comments
M – measurement
P – precision
R – redundancy
1 2 3 4
1. LOADS AND ACTIONS OF THE ENVIRONMENT
Hydraulic and sediment loads
Water level Communicating F: very high Important measurement.
vessels L: low The measurement range
Floats M: above the ridge must include the levels in
Limnimeter (parapet level) the event of flash
Pressure gauges P: ± 10 cm flooding
Pneumatic probes R: indispensable Possibilities for automatic
Acoustic (sound) measurement and data
probes recording for most of the
Pressure probes instruments
Cable with sound and
Level of sedimentary Water depth F: moderate The depth of erosions is
deposits measurements L: no also measured
M: throughout the
(Deposits in the reservoir entire depth
and in front of the inlets; P: ± 0.2 - 0.5 m
Sediment loads) R: not required
Air and water Thermographs F: moderate These instruments can be
temperature L: moderate easily replaced.
Continuous recording M: -30 C to +40 C With the possibility of
External thermal loads of air temperature P: ± 1°C carrying out automatic
Influence on snow variations R: necessary measurements and data
Normal thermometers F: moderate These instruments can be
L: moderate easily replaced
Minimum, maximum M: -300C to +400C
and instantaneous P: ± 1°C
values R: recommended
Electric thermometers F: moderate These instruments can be
L: moderate easily replaced
M: -300C to +400C With the possibility of
P: ± 1°C carrying out automatic
R: recommended measurements and data
1 2 3 4
Temperature inside the Normal thermometers F: very high A measurement range up to
concrete L: very high +60°C is only necessary
Inside holes made in M: -100C to + 600C during the building period.
the concrete P: ± 0.50C For measurements during
R: necessary, sufficient operation, a measurement
instruments must be range up to +30°C is
Electric thermometers F: very high A measurement range up
L: very high to +60°C is only
M: -100C to + 600C necessary during the
P: ± 0.50C building period.
R: necessary, sufficient For measurements during
instruments must be operation, a measurement
provided range up to +30°C is
With the possibility of
carrying out automatic
measurements and data
Temperature of the Fibre optic F: very high A measurement range up to
concrete temperature sensors L: very high +60°C is only necessary
M: -10 0C to + 60 0C while building a concrete
Circulation of water P: ± 0.5 0C dam.
through the filler R: necessary For measurements during
materials. operation, a measurement
Changes in temperature range up to +30°C is
due to infiltration sufficient.
Filler materials: a
measurement range up to
+30 °C is sufficient; on the
surface of tracks up to
Relatively easy to install.
With the possibility of
carrying out automatic
measurements and data
Rainfall within the dam Rain sensors F: moderate These measurements are
area L: low absolutely necessary in the
Accumulators M: total precipitation vicinity of the dam.
Influence of effluents during the With the possibility of
Pluviometers measurement period carrying out automatic
P: ± 10 % measurements and data
R: not required recordings
1 2 3 4
Contractions in the Earth pressure cells F: moderate Rarely used.
filler materials and the L: high The deformation modulus
concrete M: total coverage (0 - must be adapted for filler
300 kN/m2) materials.
P: ± 5 % of M Problems in interpreting the
R: not required results.
With the possibility of
carrying out automatic
measurements and data
Tele-pressure cells F: moderate Very rarely used.
L: high Interpretation and results
M: total coverage (0 - can be problematic.
10000 kN/m2) With the possibility of
P: ± 5 % of M carrying out automatic
R: not required measurements and data
2. DEFORMATIONS AND DISPLACEMENTS (DAMS AND ADJACENT AREAS)
Spatial measurements Triangulation. F: very high The geodetic monitoring
Punctual displacements, Depending on the L: very high network must cover a large
including the influence situation, combined P: needs to be area and enable long-term
of adjacent areas with: established observation of the
Levelling depending on the deformations of the dam
Electro-optical distance situation and its adjacent areas, as
measurements R: absolutely well as control of the
Optical pendulums, necessary, through possible displacement of
pendulums measures such as: the reference point using
Alignments - numerous other measurement devices
Extensometers measurement points (redundancy).
- combination with Precision measurements
other measurement that can only be performed
methods at large intervals of time.
Require the stipulation of
limited measurements for a
quick assessment of
All data and indications
relating to assessment
measurements and methods
must be filed (included in a
1 2 3 4
Satellite-assisted F, L, P : need to be The precision depends on
(GPS) measurements established the length of the
In relation with depending on the measurements (distances
terrestrial situation; between the measurement
measurements R: necessary; with points) and the height of the
(triangulation network repeated satellite (distance between
consolidation) and on- measurements or the satellite and Earth).
side inspections. other measurement Automatic measurement
methods. and recording possibilities
Photogrammetry F, L : need to be In general, aerial photos;
For displacements of established terrestrial photos are also
the ground and glaciers depending on the possible.
situation Long-term quality of the
P: ± 0.20 m photos is required.
R: not important Photogrammetry can also
be used to monitor
taking place in the
Laser scanners F: very high Modern measurement
Full scanning of the L: very high methods that can easily
surface of an object P: needs to be replace photogrammetry
depending on the
R: not important
Deformations from Levelling F: very high Widely-used and simple
horizontal or vertical L: very high method when modern
lines P: needs to be instruments are used
Expansion during established Groups of reference points
springing and valley depending on the must be raised on both
slopes situation banks
R: depending on the
Simple angular F: very high Well-tested but delicate
measurements and L: very high measurement method It is
electro-optical distance P: needs to be recommended to be used
measurements established only where pendulums
depending on the cannot be installed.
situation The measurements require
R: possible by repeated favourable weather
measurements or conditions.
triangulation The precision depends on
the distance and refraction.
Optical alignment F, L, M, P : need to be Well-tested and simple
established measurement method.
depending on the The measurements require
situation favourable weather
R: absolutely necessary conditions.
in combination with The precision depends on
triangulation and the distance and refraction.
1 2 3 4
Polygons F, L, M, P : need to be Very accurate
depending on the Combination with
situation triangulation and
R: absolutely necessary pendulums is absolutely
in combination with necessary.
Deformations from Pendulum F: very high Widely used measurement
horizontal and vertical Inverted pendulum L: very high and precision device.
lines. Two-directional M: calculated Short measurement time.
Expansion during measurement device, maximum Instrument control station
springing and valley with optical view of the deformation + Tele-transmission is
slopes pendulum string. The 50 % possible; the measurement
string serves as a P: ± 0.2 mm device must not influence
vertical reference axis R: absolutely the position of the
necessary, through pendulum.
means such as:
- combination with
String alignment F: very high Equivalent to pendulums.
Uni-directional L: very high The precision depends on
measurement device M: calculated the length of the string.
with optical view, maximum Applicable to rectilinear
which marks a vertical deformation + structures only.
reference plane. 50 % Maximum length limited by
P: ± 0.2 mm the quality and weight of
R: absolutely the string.
necessary, through Instrument control station
means such as: Tele-transmission is
- additional possible
- combination with
Settlement (vertical F: very high Piping elements < 6 m.
displacement) L: very high Verticality during
sensor M: 50 to 100 m installation must be
P: ±5 cm (during the carefully checked.
building stage) Difficulties with inclined
±1 cm (during systems.
operation, after re- Possible combination with
R: required, together
1 2 3 4
Hydraulic levelling F: high Communicating tubes with
system L: high direct reading through a
M: a few metres glass tube (three tubes for
P: ± 1 cm one measurement point)
R: necessary, together Very accurate; sometimes
with a settlement and delicate; sensitive to
levelling sensor freezing.
It is necessary to discharge
the gases from the
Length variations Distometer/Distinvar F: high Accurate measurement of
L: high distance in galleries or on
M: 10 cm for site.
distometer The distometer has the
5 cm for distinvar ability of measuring along a
P: ± 0.2 mm given distance; the distinvar
R: necessary, by can only measure
measurements or If the readings are outside
metric tape the measurement scale, the
measurements string itself can extend or
Length variations and Rod or string F: high Placing the anchors and
deformations along the extensometers L: high injecting the protective
bore hole. With one or several M: 10 to 50 mm sheath are critical
Global measurements rods (strings) P: ± 0.2 mm operations.
over long intervals or R: not always Automatic measurement
differential necessary; and recording possibilities.
measurements along a can be made by:
chain of short intervals. - installing an
- dividing the total
length into several
- combination with an
inverted pendulum or
Rod extensometers for F: high Placement of the anchors
dams made of filler L: high and injection of the
materials. M: 10 to 30 cm protective sheath are
With one or several P: ± 1 mm critical operations.
rods. R: not always Automatic measurement
necessary; and recording possibilities.
can be made by:
- dividing the total
length into several
1 2 3 4
Length variations and Fibre optic F: very high Relatively easy to install
deformations along the extensometers L: very high Automatic measurement
bore holes. With one or several M: 1 to 2 % of the and recording possibilities.
Global measurements rods section measured
over long intervals or P: ± 0.2 mm
differential R: - not always
measurements along a necessary;
chain of short intervals. - can be made by
Bore micrometers F: high High accuracy, which
Differential length L: high depends on the instrument
variations M: expected guiding system
Bore micrometers deformation + Some instruments provide
with inclinometers. 100 % very accurate and reliable
Differential P: ± 0.2 mm for length results.
deformations combined variations; Placing and injecting the
with bore micrometers. ±0.02 mm/m for guide sheaths is a critical
Inclinometers rock deformations; operation.
Differential ±0.2 mm/m for Recommended in
deformations in the weak ground identifying discontinuities
bore hole deformations (cracks and/or joints) and
R: In accordance with drift surfaces and observing
the purpose their movements.
The measurements and
interpretation take a long
Variations of local Clinometers F: high Near cavities, the results
rotations With hydraulic settling L: high are usually influenced by
marker and electronic M :20 mm/m concentrations of stresses
In the vertical plane display micrometer P: 0.02 mm/m and transfer effects.
Tiltmeter R: this measurement is The results can be
with electronic display recommended only improved by short chains of
in combination with measurement intervals.
other measurement Automatic measurement
systems such as a and recording possibilities
pendulum or for the tiltmeter.
Crack and joint Micrometer F: moderate Usually, the measurements
movements Deformeter L: high carried out inside the walls
Dilatometer M :10 mm of a gallery or in a recess
On the surface, Deflectometer P: ± 0.05 mm are not representative for
extensions and tangent R: In accordance with the behaviour of the entire
movements the purpose assembly.
and recording possibilities.
1 2 3 4
Specific deformations Concrete-embedded F: high Frequent failure
electronic deformeter L: high (malfunctions) of the
For checking stresses Combined with M: specific instruments.
inside the concrete temperature deformations 2 The behaviour is usually
measurements mm/m influenced by the local
temperature -100C to material conditions present
+500C at the location of the
P: elongations 0.02 instrument.
mm/m Analysis of the data
Temperature ±0.20C recorded is problematic.
R: necessary, through Automatic measurement
means such as: and recording possibilities.
- very numerous
- other types of
Infiltration flow rates (quantity of water)
Quantity of water Volumetric F: moderate Method is limited to
infiltrated and drained measurements using L: moderate moderate flow rates of up
calibrated recipients M: maximum expected to 10 l/s
Per area or in total and timers, or by flow rate + 100 % The recipient refill time
volume deviations (e.g. P: ± 5 % of M must be at least 20 seconds.
using a calibrated rod R: repeated
in bore holes tilting measurements
Spillway F: high Any sediments must be
Measurement channel L: high periodically removed
With scale, ultrasonic M: maximum expected Not recommended for flow
sensor, pneumatic flow rate + 100 % rates <0.05 l/s
scale, pressure probes. P: ± 5 % of M A recorder and alarm
R by volumetric device (alarm signal) must
measurements be installed in all collection
points for the total dam
and recording possibilities.
Pipe flow F: high Simple means for periodic
measurements, for L: high inspection of the readings
example in the water M: maximum expected provided by the pressure
drainage pump pipes flow rate + 100 % gauge, spillways,
- Venturi meter (to P: ± 5 % of M measurement channels, free
measure pressure R by volumetric level flows.
differences) measurements in Automatic measurement
Ultrasonic sensors or different locations and recording possibilities.
1 2 3 4
Flow measurements in F: high Simple means for periodic
partially-filled pipes L: high inspection of the readings
Ultrasonic sensors or M: maximum expected provided by pressure
magneto-inductive flow rate + 100 % gauges, spillways,
measurements (flow P: ± 5 % of M measurement channels with
speed measurements) R: by volumetric free level flow.
measurements in Automatic measurement
different locations and recording possibilities.
Measurements of hydraulic pressure in rocks and weak ground
Water pressure in Piezometers: open F: moderate The bore hole (bore hole
rocks systems L: high lining) must be leak-tight
Pressure of the water Water level M: total length of the up to the pressure
that circulates through measurements using a bore hole measurement area;
the foundation (under- cable with luminous or P: ± 0.05 m protecting the bore hole
pressure, interstitial acoustic signals R: necessary: head against the penetration
water pressure inside the installation of of surface water, mud,
rock cracks) piezometric groups stones, etc.
Permanent airing must be
Piezometers: closed F: high Widely used method.
systems L: high The pipes and connections
M: Total elevation to the pressure gauges must
Pressure readings by level difference be leak-tight.
means of pressure between the Avoid causing artificial
gauges or electric pressure gauge and pressure discharges to be
sensors the dam ridge able to measure the
P: ±0.5 m, or 1 % of M, maximum pressure, even if
respectively it takes a long time.
R: necessary; Periodic airing of the pipes
installation of is necessary
piezometric groups Periodic inspection of the
pressure gauges is
and recording possibilities.
Piezometers: F: high Centralised reading of the
(pneumatic or L: high pressures inside cells
electric) pressure cells M: Total elevation spread throughout the
Installed inside the bore level difference depth.
hole: one or more cells between the Careful selection of the
per level pressure gauge and type of filter to be used, in
the dam ridge order to avoid its early
P: ±0.5 m, or 1 % of M, clogging
respectively Accurate placing of the
R necessary; installing cells (elevation level), even
a large number of cells, if several of them must be
or installing them as installed in the same bore
and recording possibilities.
1 2 3 4
Water pressure in Piezometers - open F: moderate The bore hole (bore hole
weak ground systems L: high lining) must be leak-tight
Water level M: total length up to the pressure
measurements using a P: ±0.05 % m measurement area;
cable with luminous or R: necessary; protection of the bore hole
acoustic signals installation of head against the penetration
piezometer sets of surface water, mud,
Permanent airing must be
Checking the good
operation of the equipment
by flushing (repeated
Piezometers – closed F: high Widely used method.
systems L: high The pipes and connections
M: Total elevation to the pressure gauges must
Pressure readings by level difference be leak-tight.
means of pressure between the Avoid causing artificial
gauges or electric pressure gauge and pressure discharges to be
sensors. the dam ridge able to measure the
P: ±0.5 m, or 1 % of M maximum pressure, even if
R: necessary: it takes a long time.
installation of Periodic airing of the pipes
piezometer sets is necessary
Periodic inspection of the
pressure gauges is
and recording possibilities.
Piezometers: F: high Centralised reading of the
(pneumatic, electric or L: high pressures inside cells
hydraulic) pressure M: Total elevation spread along the depth.
cells level difference Hydraulic measurements
Installed in the between the are only possible if the
embankment, in the pressure gauge and measurement station is
bore holes, one or the dam ridge located below the minimum
several cells per level P: ±0.5 m, or 1 % of M, pressure level.
respectively Careful selection of the
R: necessary: installing type of filter to be used, in
a large number of cells, order to avoid its early
or installing them in clogging
sets Accurate placing of the
cells (elevation level), even
if several of them must be
installed in the same bore
and recording possibilities.
1 2 3 4
Physical and chemical properties of water
Recordings of physical Turbidimeter F: high Determining the suspension
and chemical L: high or dissolved materials
modifications M: 0 to 500 ppm It is important to provide a
P: ± 1 ppm local cabin (shelter).
R: necessary: by Calibration after laboratory
analysing water analysing of infiltration
samples in a laboratory water.
and recording possibilities.
Chemical analysis F: high To be carried out at long
L: no periods of time
M: depends on the The main characteristics
values expected must be determined by
P: depends on the specialists.
R: not required
4. GLOBAL INVESTIGATIONS AND MEASUREMENTS
Geophysical methods Seismic reflections F, L, M, P – need to be Application and
Seismic refractions set depending on the interpretation of the results
Geophysical Geo-electrical situation must be carried out by
determinations of the Electromagnetic specialists.
dam and foundation Geo-radar R: necessary; depends
ground characteristics Geomagnetic on the situation, by
Gravimeters drilling, samples,
Seismic tomography tests, other
Infrared land surveys methods
Video inspections Underwater robot F, L, M, P – need to be Good underwater visibility
For points that are with video camera set depending on the It is necessary to ensure the
difficult or impossible to situation location of the robot.
access R: not required
Drill hole video F, L, M, P – need to be The current/water flow can
set depending on the worsen the visibility
R: not required
Characteristics of Sclerometer R: moderate Measurements using test
concrete (Schmidt hammer) L: no specimens in situ.
M: probable compression The results are only valid
Test without damaging resistance +100 % for the surface area.
the concrete surface P: ± 20 % of M
R: necessary; laboratory
Laboratory tests F, L, M, P – need to be Test specimens are small
using test specimens set depending on the compared to the size of the
R: necessary; large
number of tests
1 2 3 4
Detecting water Measurements of F: very high New method
circulation temperature L: very high The optical fibre has the
variations caused by M: from -100C to ability to identify
Locating the infiltration + 300C temperature changes
concentrated infiltration Measurements of P: ±0.50C occurring along a pipe
points temperature changes R: necessary; sufficient due to water circulation.
due to water instruments must be
Inspection of anchors Anchoring force F: high The load measurement
measurements L: high cell must be controllable
For ground anchors In the (electric or M: Anchoring force and replaceable.
hydraulic) anchor head +25 % Automatic measurement
P: ± 1 % of M and recording
R: necessary possibilities.
Recordings of seismic Seismometer F: high Devices equipped with 3
activities (records the movements L: moderate measurement components
of the support over time M :± 1 g (amax) must be provided.
(speed and P: a 0.03 mg At least 3 devices must be
acceleration) ( 16 Bits) installed (at ridge level, at
t 0.005 sec. foundation level and in
Seismograph the free field).
R: necessary Application and
accelerations over time) interpretation of the
results must be carried
out by specialists.
2. COMPULSORY REQUIREMENTS FOR THE MONITORING SYSTEM
2.1. General elements
(1) There is no technical regulation that establishes the number of monitoring instruments that
must be installed. The number varies depending on the type of dam and its dimensions, the way in which
it is built, its age and specific site conditions, especially those related to the foundation ground. The
concept of the monitoring system must take into account the fact that the structure and its foundation form
a unitary system, but the equipment must record the behaviour of each sub-system on an individual basis.
(2) The dam behaviour assessment is largely based on interpreting the data provided by the
monitoring system. The UCC operator is obliged to make sure that the readings provided by the
monitoring equipment are accurate and plausible, and then validate them. The UCC engineer is the first
person who has the obligation to interpret the readings, “online” if possible, and check whether the
behaviour of the dam is within the normal limits. Otherwise, depending on the severity of the situation,
specific procedures must be activated in order to identify the causes, potentially with help from experts.
(3) Figure 2.1  depicts a monitoring system organisational diagram structured on levels of
activity and competence that is used in most countries having a tradition in building and operating dams.
Level IV Public authority authorisations or licences
for safe operation
Safety assessments at
Level III (employed by the intervals (5-7 years)
Analysis and interpretation of
Experienced specialists measurements
Annual technical inspections
Annual safety reports
Local ECC team Equipment manoeuvers
Level I (owner) +
Processing and primary
Fig. 2.1 Organisation of the dam behaviour monitoring system in countries having a tradition
(according to Biedermann ).
(4) The activity is structured on four levels. The first two levels involve a timely safety check and
prompt identification of all situations that pose an increased risk. The owner’s local team collect data
(visual inspections, MCD measurements, equipment manoeuvring) and performs their primary
interpretation (in real time). Level II consists of a group of experienced specialists who interpret the data
collected and measured by the local team. The level II specialist team also carries out periodic technical
inspections and draw up annual reports about the behaviour of the structure.
(5) Levels III and IV are organised in accordance with the specific technical regulations in force in the
field of dam safety and hydrotechnical facilities. The safety assessment carried out by certified technical
experts represents a basic inspection of all factors that have significant effects on dam safety: the
condition of the structure, its behaviour during operation, developments inside the reservoir, the response
of the structure to extreme stresses, operating instructions, level of personnel training, etc.
(6) If the conclusions of the expert survey report are positive, they shall represent the technical
justification for issuing an authorisation (permit) for the safe operation of the structure. The authorisations
are issued by the central or local public authority, depending on the importance of the structure, on the
basis of the permit issued by a national commission set up in accordance with the law.
(7) In accordance with the provisions of Government Emergency Ordinance No 244/2000 on dam
safety, UCC activities in Romania shall be organised on three levels, based on a diagram similar to the one
given in Figure 2.1:
level I takes place at the dam and consists of visual inspections, measurements using the
measurement devices, processing and primary interpretation of the results exceeding the criteria
for checking the warning, all of which shall be carried out by operating personnel who are assigned
level II includes the periodic summarising of the visual observations and measurements carried out
at level I, as well as the annual inspections, interpreting them from a dam safety point of view; this
summary is prepared by specialists who draw up annual summary reports, through the care of the
level III consists of analysing and approving the annual summary reports, which is done by a
committee in charge of tracking the behaviour of dams over time.
(8) Monitoring efficacy within the dam safety management system is mainly achieved through the
activities carried out at level I of organisation. The analysis carried out at this level must be accurate, quick
and easy to apply by any personnel with high-school level of education. Therefore, the solution usually
adopted involves a direct comparison of the results of measurements carried out using critical values. The risk
posed by accumulation works is multiple (hydrologic, seismic, structural, etc.), and the values of the
parameters tracked by means of measurements as part of the monitoring activity depend on several external
factors (water level in the reservoir, temperatures, etc.). As a result, the normal range for a response parameter
that is very important for safety can only be characterised by values which depend on external factors
themselves. For this reason, the notion of warning criteria was introduced, which better matches the complex
nature of the phenomena that increase the risk.
(9) Operating dams can operate in a normal situation or an exceptional situation. A normal situation is
characterised by normal values of the external stresses (reservoir levels, affluent or defluent discharges,
temperatures, etc.), the correct operation of the components of the facility and the stress response of the
structure in line with the one forecast. Failure to comply with any of these requirements shall lead to the
normal situation changing into an exceptional situation (in accordance with the technical regulations in force
on tracking the operating behaviour of hydraulic structures).
(10) For an exceptional situation, there are several states depending on the gravity of the deviation
from the normal situation and the degree of risk posed by this:
the state of caution represents a mere deviation from the normal operating parameters, without
posing a threat to the safety of the structure;the state of alert is triggered when phenomena whose
development could pose a threat for the area located downstream from the reservoir are observed;
the state of alarm is triggered by the need to discharge certain volumes of water, which floods
downstream areas and/or poses an imminent threat of damage or even rupture of the dam.
(11) The warning criteria which delimit the operating situations and states of a dam and have a direct
effect on the way in which the monitoring activity is carried out, are established so that they can be
applied immediately, without having to wait for the results of any additional analysis. These are stipulated
in the Structure Behaviour Tracking (UCC) Design, which is an integrated part of the operating rules.
(12) The warning criteria shall be established when designing the structure, as part of the monitoring
design. They shall be updated with each structure behaviour analysis documentation (periodic documentation
or special analyses determined by unusual events), but also whenever the operating conditions change.
2.2. Example of equipping a concrete dam
(1) The parameters that are normally monitored for concrete dams were presented in Chapter
(2) The number of monitoring instruments installed in the body, foundation and slopes of dams is
very different from one structure to another, and can vary from a few hundreds to 2 000-2 500. It varies
depending on the importance of the structure and the quantity of information that the design engineer
deems necessary in order to ensure dam safety.
(3) Figure 2.2 presents typical diagrams of the UCC equipment used for an arched dam and a
gravity dam, respectively.
Direct pendulum Rockmeter
Inverted pendulum Interstitial pressure cells
Extensometer Total pressure cells
Fault spillway Topographic and geodetic
Fig. 2.2 Typical diagrams of the UCC equipment used for an arched dam and a gravity dam, respectively
(4) An actual description of the UCC equipment used for a concrete dam is given below, using the
Gura Raului dam as an example (a buttress dam, H=72 m). Table 2.1 presents the parameters monitored in
the body of the dam, as well as the types of instruments used. The parameters monitored in the foundation
and slopes are presented in Table 2.2.
(5) The number of instruments installed at the Gura Raului buttress dam during its building period
(1970-1978) and those who were still operational in 2006 can be found in table 2.3. From these, we can
note the very good reliability of the MCD equipment installed in the body and foundation ground of the
dam, except for drainage bore holes made in the slopes and pressure telemeters.
Parameters monitored inside the Types of instruments
Horizontal displacements Direct and inverted pendulums
Settling Fixed-point monitoring network
Deformations and stresses in the Concrete-embedded deformation
Temperature of the concrete after Concrete-embedded thermometers
pouring Bolts to the adjacent blocks
Relative displacements of the Thermometers
blocks on the joints Regulating spillways. Flow meters.
Temperature of the environment Staffs. Limnigraphs. Tele-
(air, water) limnigraphs
Infiltrations Accelerometers. Seismometers
Water level in the reservoir Pressure transducers
Vibrations. Seismic events
Parameters monitored in the Types of instruments
foundation and slopes
Interstitial pressure (rocks) Pressure transducers
Pore pressure (soils) Piezometers
Displacements (horizontal, vertical) Rockmeters. Clinometers
Inverted pendulums (horizontal
Regulating spillways. Flow meters
Crit Type of instrument Installed In operation
eria (1970-1978) in 2006
1 Direct pendulums 4 4
2 Inverted pendulums 2 2
3 Three-rod Rockmeters 7 7
4 Deformetric bolts (positions) 28 27
5 Hydrometers 22 22
6 Drainage bore holes between 75 75
7 the blocks 6 3
8 Drainage bore holes in the 26 11
9 slopes 87 85
10 Pressure telemeters 4 4
11 Concrete telethermometer 4 4
12 Air telethermometer 14 14
Clinometric bolts (positions)
Figures 2.3 and 2.4 show the location of the monitoring geodetic network and the main
measurement devices installed at Gura Raului dam.
Fixed stationary pilaster
Reservoir Fundamental levelling
bypass road marker
R.E.D. Fixed spatial marker
Fig. 2.3. Gura Raului dam – Layout with the geodetic network.
Rs4 Pendulum Pendulum Pendulum Rs21
BLOCK 7 BLOCK 18
BLOCK 11 BLOCK 14
Fig. 2.4. Gura Raului dam – Location of the measurement devices.
(6) The data obtained from monitoring concrete dams (monitoring + visual inspections) are mainly
used for the following purposes: general verification of the stability and stress levels of the structure;
assessment of the operation of the sealing and drainage system; detection of any fissures (cracks) and
identification of their generating causes. The data relating to the foundation and slopes of the dam are used
for the following purposes: to assess the stability of the foundation and slopes in the dam and reservoir
area, identify any potential outflow points in the dam and reservoir area, and assess the efficacy of the
sealing (grout curtains, sealing screens) and drainage systems.
2.3. Example of equipping a dam made of filler materials
(1) The parameters that are normally monitored for dams made of filler materials were presented in
(2) Figure 2.5 presents typical diagrams of the UCC equipment used in a dam made of filler materials
with a core of clay and a dam made of filler materials with a concrete mask, respectively.
Dam made of filler materials
with a core of clay
Accelerograph Dam made of filler
Topographic and geodetic markers
materials with a reinforced
Interstitial pressure cells
Total pressure cells
Inclinometer and vertical settling
Fig. 2.5 Typical diagrams of the MCD equipment used in dams made of filler materials
(3) Table 2.4 presents the types of instruments according to the parameters measured.
Parameters monitored at Types of instruments
dams made of filler materials
Displacements (settling) Topographic and geodetic
instruments and methods
Pore water pressure in earth and Clinometers
sealing elements Pressure transducers
Infiltrations (position of the Piezometric tubes
infiltration curve) Piezometer with controlled flow
Total stresses. Pressures
Slope displacements Pressure telemeters
Deformation state (stresses) in Rockmeters
concrete structures associated with a Teleformeters. Electro-acoustic
dam made of filler materials extensometers
(4) The number of monitoring instruments installed in the dam-foundation system of dams made of
filler materials differs from one structure to another and can reach a maximum of 1 500- 2000. Compared
to concrete dams, the number of monitoring instruments installed in dams made of filler materials is
(5) Table 2.5 presents the main parameters being monitored, as well as the types of instruments
used at Siriu dam ( H 122 m, an earthfill dam with a core of clay).
Parameters monitored Types of instruments Number of items
A External factors
Water level in the reservoir hydrometer 1
Air temperature thermometers 2
Precipitation pluviometer 1
B. Response of the structure
Displacements – settling Geodetic network for
and accurate levelling
Relative displacements of the inclinometer columns
dam body made by SINCO
dilatometric clips in 15
Relative displacements of gallery 611
auxiliary concrete structures
drainage bore holes
63 items with 10
Infiltrations piezometric bore collection points
holes 23 items (10 in
Piezometric levels (prism operation)
and foot downstream of the
dam, slopes) electro-acoustic 69 total pressure cells
transducers made by (38 in operation)
Total pressures and pore TELEMAC (France) 99 pore water cells (48
pressures in the core in operation)
Response to seismic actions
(6) Figures 2.6 and 2.7 present the location of the microtriangulation and accurate levelling
markers, as well as the drainage bore holes at Siriu dam. In the period of over 20 years since the partial
commissioning of Siriu reservoir, the monitoring system has supplied sufficient information to enable
assessment of the current level of safety of the dam and prevent the occurrence of atypical situations.
Boundary stone with spatial study marker
Boundary stone with bolt (level study)
Supporting level marker
Transport level marker
Fig. 2.6. Siriu dam – Location of the geodetic equipment.
Right bank Left bank
Gallery G10 Gallery G5
Fig. 2.7. Siriu dam – Longitudinal profile with the distribution of drainage bore holes in galleries G11 , G3
and G4; 1 – dam body; 2 – limit of the watertight diaphragm; 3 – high water spillway.
2.4. Primary operational processing of the measurements. Behaviour models for diagnosing
the safety of the structure.
(1) The dam behaviour tracking activity is carried out in several successive or simultaneous stages,
which are briefly presented below:
a)- Carrying out observations and measurements – collecting information via periodic inspection
of the structure.
b)- Primary processing – turning the variables measured into variables used in UCC. This
operation can be carried out before or after introducing the data into the computer.
c)- Introducing the data into the database used both to preserve the information over time and to
transmit it to the next processing and interpreting levels.
d)- Checking the “normality” of the behaviour by comparing the measurement results with the
results obtained by calculation using a behaviour model, for the external stresses present at the time of
measurement. The operation can be carried out manually (using models processed in a graphic format) or
on the computer (using an analytical relationship as a model). If entering an extraordinary situation, the
measurements can be performed with increased frequency and, if applicable, special analyses are carried
out to explain the phenomena observed.
e)- The analysis of atypical phenomena involves, in the first instance, a separation of the external
stresses from the time factor, to see whether the phenomenon is developmental or not, and how it reacts to
any potential operating measures taken to keep it under control.
(2) The above mentioned operations are, in general, characteristic for the local analysis level.
a)- Re-analysing the data obtained in the previous analysis stages in the graphic format of
development over time of the measured variables and, potentially, eliminating those points for which there
is evidence of gross error.
b)- Selecting the characteristic values for the variations recorded during the period being analysed:
average, minimum, maximum, variations etc. and comparing them with the values characteristic to the
previous operating periods.
c)- Determining the essential parameters for defining the behaviour of the dam, taking into account
the type of structure, the site problems and the previous behaviour.
d)- Establishing the behaviour models for the essential parameters that characterise the behaviour
of the dam, by statistical processing of the measurements carried out.
(3) Figure 2.8 presents the diagram of the dam safety assessment stages based on the data obtained
from the monitoring system.
- auxiliary structures (spillways, drains, hydroelectric power plant, etc.);
- dam, foundation, reservoir and its slopes;
- behaviour tracking system;
- warning-alarm system.
Items being monitored:
Preliminary Preliminary Preliminary Preliminary
analysis analysis analysis analysis
GLOBAL DAM SAFETY ASSESSMENT
Figure 2.8. Diagram of the dam safety assessment stages based on the data obtained from the monitoring
3. SPECIAL TRACKING DESIGN
3.1. General data and content of the design
(1) The special tracking design shall be drawn up in accordance with the applicable normative
documents regarding quality in construction, as well as the specific technical regulations in force
regarding the behaviour of structures over time and the behaviour of hydraulic structures.
(2) The special tracking design shall be drawn up as follows:
- for new hydraulic structures, by the design engineer of these structures, during the initial design
- for existing, operational hydraulic structures which belong to importance categories A and B, or
for which special tracking was instituted by the initial design engineer or specialised design
companies with the approval of a certified technical expert, where applicable, following technical
(3) The person appointed by the owner to be responsible for the special tracking of the dam
behaviour shall be authorised for this activity in accordance with Law No 10/1995 regarding quality in
construction, with its subsequent modifications.
(4) The personnel appointed to carry out the special tracking of the behaviour of structures shall
present the results of this activity by means of reports, on the dates set in special tracking design which
shall be included in the log book of the structure through the care of the person responsible for the special
tracking of the respective structure.
(5) The special tracking design shall be periodically updated by means of comments relating to the
behavioural development of the hydraulic structure, the condition of the MCDs and any changes in the
(6)The special tracking design shall primarily have the following content:
- name and location of the facility;
- reasons for instituting the special tracking;
- a description of the structure (type of structure, general characteristics, materials used,
dimensions, characteristics of the foundation and environment, etc.);
- special tracking objectives (parameters, phenomena, assessment criteria, building quality
- determining the critical points of the structure and locating the MCDs;
- requirements for acceptance, inspection and storage of the equipment;
- establishing the methods used to collect, record and transmit the data measured by the MCDs and
those obtained by direct visual observations;
- establishing the method used to archive and keep the data;
- establishing the method used for primary processing and comparison with the control values
(normal, caution, alert, alarm), as well as the responsibilities for making decisions in various situations;
- establishing the limit behaviour and safety situations;
- the frequency of measurements.
3.2 Frequency of measurements
(1) The frequency of direct visual observations and measurements using the equipment installed in
the dam-foundation system is part of the special tracking design and is initially established by the designer
of the facility and can subsequently be adapted depending on the behaviour of the structure and at the
proposal of its owner.
(2) The frequency of direct visual observations and measurements using the equipment installed in
the dam-foundation system shall be established for each stage in the life of the structure: execution, first
setting into operation, current operation and, potentially, special situations which could occur during any
of the above mentioned stages.
(3) The frequency of the direct visual observations and MCD measurements shall be established as
a function of the speed of variation of the parameter or phenomenon being tracked, their effects on the
structure, as well as the condition of the structure (normal/atypical behaviour, degree of aging, etc.).
(4) Table 3.1 presents the frequency of measurements using the MCDs installed at the Driru dam
on the Ialomita river, in accordance with the special tracking design, both for normal and exceptional
Parameters being Type of device M.U. Frequency
m normal exceptional
1 Reservoir level Hydrometer mdM 1/day 1/day
2 Precipitation Pluviometer mm/da 1/day 1/day
3 Infiltrated volumes Drainage bore holes l/min 1/week 1/day
4 Under-pressures Drainage bore holes mdM 1/week 1/day
5 Piezometric levels Piezometric bore mdM 1/week 1/day
6 Total pressures TPT bar 1/week 1/day
7 Interstitial pressures TPI bar 1/week 1/day
8 Relative Dilatometric clips mm 1/week 1/day
9 Absolute Geodetic network mm 2/year
10 Reservoir clogging Bathymetric profiles mdM 3-5 years After flash
11 Downstream river bed Bathymetric profiles mdM 3-5 years After flash
12 Visual observations daily Special
Direct visual observations can be classified in one of the following situations:
- periodic, according to a well-established calendar schedule, in accordance with table 3.2:
Frequency Who carries them out Who checks Where they are recorded
A Daily The entire personnel Foremen Shift register
B Weekly Foremen UCCH manager Shift register
C Monthly UCCH manager Operating Events register
D Yearly A committee appointed by the The PV
- during extraordinary stresses;
- following extraordinary stresses;
- when identifying the presence of atypical phenomena: occurrence of wetting, outflows, signs of
displacement, cracking, etc.;
- when re-assessing the level of safety, following a longer period of operation.
(5) To ensure that the direct visual inspection activities are carried out in good conditions, the
obligations that the personnel have with regard to periodic observations (the route that needs to be
followed, the points and phenomena being tracked, frequency, etc.) must be stipulated in their job
(6) It is extremely important to check that the inspection schedule is complied with. This can be
done in different ways, going so far as to record certain events in the system and track the moment when
they are reported by the personnel.
(7) All inspections, apart from periodic inspections, shall be carried out by teams which should
include specialists from various fields: constructors, geologists, mechanics, etc.
(8) The content of the visual inspection carried out in order to re-assess the level of safety is
stipulated in special recommendations.
(9) The head of the structure behaviour monitoring department or that person’s deputy must be a
member of the committees responsible for carrying out all inspections apart from periodic ones. Any
findings shall be recorded in a report signed by the inspection committee and endorsed by the
3.3. Content of annual reports and summarising reports relating to the behaviour of the
(1) The analysis documentation relating to the behaviour of the structures contain summaries of the
data referring to the condition and behaviour of the structures over a given period of time.
(2) The purpose of this documentation, which are usually drawn up on an annual basis, is to
establish whether any phenomena that could affect the safety of the structures occurred during the
reference operating period, guide any decisions towards potential remedy works or amendment of the
operating rules (restricted operation), and propose measures for improving the UCC activity. The
summarising documentation shall usually be drawn up once every 5 years.
(3) The framework content of the analysis documentation relating to the behaviour of hydraulic
structures in accordance with the provisions of the technical regulation on tracking the behaviour of
hydraulic structures must primarily contain the following chapters and points:
1. General data
Name, type of structure, location
Functions of the structure, importance class and importance category
Component structures of the facility
Characteristic data (geology, hydrogeology, hydrology, levels, volumes)
Short history and unusual events registered
Drawings (layout, characteristic sections, etc.)
2. Monitoring system
Objectives of the monitoring system
MCDs for external stresses
MCDs for monitoring the structures and their foundations
Changes to the monitoring system
3. Organisation of the monitoring activities
Frequency of the direct visual observations and measurements
Warning - alarm criteria
Signal that certain warning – alarm criteria have been reached
Comments on the operation of the MCDs
4. Stresses on the structure during the period being analysed
Air (water) temperature
Flash flooding registered
Changes caused by clogging, erosion
Operation of spillways
Characterisation of the stresses compared to those applied during the previous period and design
Tables and drawings (development diagrams for the entire period, and detailed diagrams for the
period being analysed)
5. Summary of visual observations
Integrity of the structure, including its foundation and slopes
Reservoir and slopes (banks)
Situation of the upstream and downstream channels
Condition of the access routes
6. Hydro-mechanical equipment in the retention field
Main technical characteristics
Condition of the structure, activating systems, seals, anti-corrosion protection, position tracking and
Condition of the access and lighting systems
Tests carried out in accordance with the operating rules
Performance of the equipment during everyday operation and during prophylactic manoeuvres
Maintenance works carried out
Application of the recommendations proposed in the previous documentation
7. Processing and interpretation of measurements
Objective and purpose of processing
Development of the measured parameters
Correlations between actions and the response parameters
Representation of the characteristic diagrams (diagram of measured variables, spatial distributions of
the measured parameters, diagrams of the normal variation range, etc.)
Interpretation of the results
- the way in which the results are classified within the predicted range
- explanation for classifying certain values
- maintaining dependencies or correlations over time
- assessment of the irreversible effects
8. Unusual events registered and measures adopted
This chapter underlines the relevant aspects resulting from the analysis carried out with regard to
the general state of the structures and MCDs, the measurement schedules, etc.
10. Recommendations for the UCC activity
The recommendations can refer to amending the special tracking design, supplementing the UCC
equipment, the measurement schedules, the caution-warning values and criteria including complementary
4. BEHAVIOUR MODELS
4.1. General elements
(1) Dams are designed based on models built on the basis of engineering practice at that time,
established based on the casuistry (works performed, incidents and accidents, observations and
measurements) registered and assimilated up until that point.
(2) The construction of conceptual models for the dam domain poses difficulties mainly due to the
fact that a dam, which has large dimensions anyway, works with a large surface of the foundation ground,
which creates very complex boundary conditions and material properties.
(3) Tracking of the behaviour over time shall be carried out by comparison with the established
model and, therefore, has a double role: to check the correspondence of the model with reality, and check
that the structure behaves normally, without any additional risks.
(4) There is a big difference between the design model and the behaviour model. The design model
analyses the situation for maximum stresses. In this case, simplifications can be admitted providing that
the result covers the safety of the structure.
The behaviour model makes it possible to obtain the response of the structure for various associations and
levels of stress.
(5) Interpretation of the data collected through the monitoring system and by direct inspection is
necessary in order to assess the level of safety of the respective structure. At present, there are several
types of basic models used to interpret the data obtained by monitoring the dams: deterministic, statistical,
based on neural networks, hybrid, etc.
4.2. Deterministic models
(1) Deterministic models are mathematical models usually based on numerical procedures (finite
elements, finite differences, border elements) capable of simulating the response of the dam-foundation
system to environmental actions. These models shall be drawn up as early as the structure design stage
and are then calibrated when the dam is activated or during the first years of operation. Calibration of the
mathematical models means correcting the physical parameters that characterise the system (mechanical,
hydraulic characteristics, etc.) so that the calculated response is as close as possible to the result of on-site
measurements. During the lifespan of the structure, alongside scientific progress, new, perfected
mathematical models, which simulate the response of the system more accurately, are frequently
(2) For example, Figures 4.1 and 4.2 show the finite element digitisation diagram of the Gordon
arched dam ( H 140 m, Australia) and one of the calculation model validation tests. The calculations were
made using the MSC/NASTRAN programme for Windows. The body of the dam was digitised using
2425 BRICK elements with 8 nodes positioned in three rows along the thickness of the dam, whilst the
foundation ground was digitised using 6325 BRICK elements. Very thin membrane elements were
attached onto the upstream and downstream face of the dam. Figure 4.2 compares the radial displacements
that occurred during the first filling in the central console at the elevation level 232 mdM (approximately
50 m above the foundation), calculated using the finite element method and measured by the pendulums
(cumulated displacements measured by the direct pendulum and inverted pendulum located in the central
console), respectively. The correspondence between the values forecast using the mathematical model and
the values registered was reasonably good. Therefore, the mathematical model was validated. The
calculations were carried out in the linear elastic range using isotropic materials with the following
characteristics: concrete Eb 24,1 GPa, 0,20 , b 2400 Kg/m3 , 11,7 10 6 0C; foundation rock
E r 16 GPa, 0,20 .
Span of valley to the edges = 170 m 50m
Dam height = 140 m
Fig. 4.1. Gordon dam ( H 140 m,
Australia) – Finite element
In the central el.console 232 mdM
(approx. 50 m above the foundation)
Mar-74 Sep-74 Apr-75 Nov-75 May-75
Fig. 4.2. Gordon dam – Validation of the calculation model by comparing the radial
displacements in the central console – elevation 232 mdM, during the first filling; 1 -
calculated using the finite element method, 2 – measured with the pendulums (direct +
4.3 Statistical models
(1) Statistical models are mathematical models based on processing the previous measurements
relating to the behaviour of the system. In the field of dams, in order to draw up a statistical model,
measurement results from the monitoring equipment must be available for a sufficiently long period of the
service life of the structure. These data are used to determine statistical correlations between certain
measured variables (displacements, infiltrations, etc.) and the external factors that cause their variation
(hydrostatic level in the reservoir, temperature, age of the dam, etc.). The values subsequently measured
are compared to those resulting from correlation based on the previous measurements, which helps assess
if the phenomenon being tracked develops according to the same law, or whether new elements or
behaviour anomalies that require analysis have occurred.
(2) Statistical models can be grouped into probabilistic models and time series. Probabilistic
methods assume that there are no cause and effects connections between the various elements of a
phenomenon, but the effect is a random variable whose probability distribution function depends on the
causes. The time series models create a correlation between the effect and its cause, together with the
statistical parameters of the series being measured. Time series modelling can be carried out by
assimilating the time series to signals that pass into the frequency range and are filtered, through the
(3) From the category of statistical models, EdF and its perfected variant, CONDOR, shall be
presented below, these models being frequently applied in dam behaviour monitoring activities.
(4) The EdF model considers that the response of the dam (X) is mainly influenced by three
external factors (hydrostatic level in the reservoir, temperature, age of the dam), whose effects add up.
X f1 (hydrostatic level) + f 2 (temperature) + f 3 (dam age) + , (4.1)
where is the approximated error of the model, due to neglected factors of little importance and
(5) Experience has shown that, on the same date of every year, the thermal state of a dam is
practically the same due to the thermal inertia of the structure. Therefore, in relationship (8.2), the
temperature function can be replaced with a seasonal function with the period of one year:
X f1 (hydrostatic level) + f 2 (season) + f 3 (dam age) + (4.2)
(6) The wide variety of the forms required for the hydrostatic law can be obtained via a 4 th degree
polynomial function of the relative depth Z in relation to the normal retention level (NNR), according to
f1 Z a1 Z a2 Z 2 a3 Z 3 a4 Z 4 , (4.3)
where Z , NNR being the elevation level of the normal retention level, NH – the level
of the reservoir on the day of the measurement, and H b – the height of the dam (depth of the reservoir).
(7) In the above form, variable Z has values between 0 and 1, regardless of the altitude and depth
of the reservoir. It particularly allows for good accuracy in numerically resolving the algebraic system of
equations. It also requires the situation of a full reservoir at NNR as the reference hydrostatic state:
f1 Z 0 when Z 0 , and NNR NH respectively. (4.4)
(8) For most phenomena, the seasonal law is correctly represented by a sinusoidal function S
associated with an unknown phase (lag) . Useful asymmetries can be introduced by completing the
expression with a harmonic of double frequency and unknown phase , resulting in:
f 2 S cos S cos 2S (4.5)
Relationship (8.6) is processed as a function of the phases and the following is obtained:
f 2 S a5 cos S a6 sin S a7 sin 2 S a8 sin S cos S , (4.6)
a7 2 cos
a8 2 sin
Di D0 Di D0
S 2 (rad) or: S 360 (degrees sexg).
The variable (S) has the value 0 on 1January and 2 (or 360 °) on 31 December.
(9) The law that takes into consideration the age of the structure (T) has a negative exponential
term which represents the dampened development, and a positive exponential term which represents the
accelerated development. Time flows from the moment the structure is activated, and considers one year
to be the time unit. The relationship has the following form:
f 3 T a9 eT a10 e T , (4.7)
where T (years); D0 - reference date of the model (dam is first activated); Di - measurement
(10) The law taken into consideration cannot represent certain atypical variations or discontinuities
which sometimes occur. However, it does generally represent a good approximation of the influence that
the age of the dam has on its response.
In the end, the complete expression of the EdF statistical model has the following format:
X a0 a1 Z a2 Z 2 a3 Z 3 a4 Z 4 a5 cos S a6 sin S
a7 sin 2 S a8 sin S cos S a 9 eT a10 e T .
(11) In relationship (4.8), coefficients (constants) a0 ...a10 are the unknown factors which are
determined on the basis of the data provided by measurements. a 0 is a constant that takes into account
the arbitrariness of the measurement state of the parameter X . For this purpose, 11 sets of measurements
shall be successively selected to form systems of 11 equations with 11 unknown factors. Each system shall
provide a set of values for the coefficients a0 ...a10 with a certain error i . The final values of the
coefficients a0 ...a10 shall be determined by minimising the errors using the least mean square algorithm.
(12) The CONDOR statistical model is a perfected version of the EdF model. In the CONDOR
model, the functions that influence the hydrostatic and seasonal level remain the same as in the EdF
model, but the function that influences the age of the structure changes. Also, errors are divided into two
categories: FN (due to neglected phenomena) and E (the measurement error of the resulting parameter).
(13) The law that takes into consideration the age of the structure (T) has a polynomial part which
represents the accelerated development, and an exponential part which represents the dampened
development. It has the following expression:
f 3 T a9 T a10 T 2 a11 e T , (4.9)
Where the term a9 T represents the linear component of the trend (accelerated development) and a10 T 2
represents the square component of the trend (accelerated development).
(14) The complete expression of the CONDOR statistical model has the following format:
X a0 a1 Z a2 Z 2 a3 Z 3 a4 Z 4 a5 cos S a6 sin S
a7 sin 2 S a8 sin S cos S a9 T a10 T 2 FN E .
(15) The EdF and CONDOR statistical models have been used, with very good results, to
determine the displacement behaviour of concrete dams. Once the coefficients have been determined, it is
possible to assess the weighting that various factors (hydrostatic level, temperature, age of the structure)
have in the response.
(16) Figures 4.3 and 4.4 show two applications of the EdF and CONDOR models in the statistical
modelling of the displacements of a pendulum and Rockmeter, respectively, at the Gura Raului dam. In
Figure 4.3, it can be noted the very small percentage difference (<2 %) between the recorded values of the
pendulum displacements and the values calculated with the EdF model. As expected, separating the
influence of various external factors on the Rockmeter displacements (fig. 4.4.) reveals that the hydrostatic
level has the most significant influence on the displacement response of the Rockmeter.
Fig. 4.3. Gura Raului dam – Application of the EdF statistical model in the assessment of upstream-
downstream displacement, inverted pendulum, block 14(a) and percentage differences between
evaluations and measurements (b).
Fig. 4.4. Gura Raului dam – Application of the CONDOR model in separating the influences of the
hydrostatic level, air temperature and age of the dam on the displacements of a Rockmeter.
External factors (Actions, Causes)
ptan -1 = 0.1
Average daily air temperature
UM = “mm” Chronological series of the modelled parameter
Smoothing with averaging of the closest values
Figure 4.5 Chronological series of the environmental parameters (reservoir level, air temperatures) and
the upstream-downstream displacements recorded and calculated using the CONDOR statistical model at
the direct pendulum in block 10 of Bradisor dam.
UM = “mm” Chronological series of influences
Influence of air temperature
Figure 4.6 Influence of the reservoir level, air temperature and aging (irreversible displacements) on the
upstream-downstream displacements recorded and calculated using the CONDOR statistical model at the
direct pendulum in block 10 of Bradisor dam.
Statistical validity limit.
UM = “mm”
Figure 4.7 Statistically-accepted limits between the values of the upstream-downstream displacements at
the direct pendulum in block 10 of Bradisor dam, measured and calculated with the CONDOR model.
(17) Figures 4.5-4.7 illustrate statistical analyses of the upstream-downstream displacements
recorded at the direct pendulum in block 10 of the Bradisor dam using the CONDOR model. The very
good correlation between the calculated values and the corresponding values recorded (correlation
coefficient 0.90), as well as the large influence that air temperature has on the dam displacements, can be
(18) The statistical models are easy to use and enable quick detection of behavioural anomalies,
the alarm signals that require quick measurements to be taken in order to return the structure to its normal
4.4 Models based on neural networks
(1) In neural networks, the information is no longer memorised in well determined areas as with
standard algorithms, but is diffusely memorised in the entire network. The memorising operation is carried
out by establishing the corresponding weighted values of synaptic connections between the neurons of the
(2) Figure 4.8 shows the diagram of an artificial neuron and the neural network used to predict the
development of infiltrations in the terrace on the right slope of Motru dam.
Figure 4.8 Schematic representations of an artificial neuron and the neural network used to predict the
levels in piezometric bore holes and the infiltrations in the right slope of Motru dam.
(3) Another important element which is, most likely, the main element responsible for the success
of these models, is the capacity of neural networks to learn from examples. Traditionally, in order to solve
a problem, you must draw up a model (mathematical, logical, linguistic, etc.) of it. Then, starting from this
model, a succession of operations must be established, representing the problem solving algorithm. There
are, however, highly complex practical problems for which it is difficult or even impossible to establish an
algorithm, even an approximate one. In this case, the problem cannot be approached using a traditional
algorithm regardless of the memory resources and calculation time available.
(4) What characterises neural networks is the fact that, starting from a multitude of examples, they
are able to implicitly synthesise a certain model of the problem. In practice, a neural network builds its own
algorithm for solving a problem, providing that it is supplied with a representative set of individual cases
(training examples). The neural network extracts the information present in the training set (learns from the
examples given). In this situation, it is said that the network is taught (trained). In the working phase – or the
reference phase – the network shall use the information acquired during the training phase to treat situations of
the same nature as the information contained in the training set.
(5) Neural network models no longer require a deterministic algorithm to be provided in order to
solve a problem. The training only requires a consistent set of examples, together with a rule for modifying the
interneural weighting. For each example, the training rule compared the desired exit (given by the example) to
the real exit of the network and determined a modification of the weightings, in accordance with a given
strategy. Usually, weight determination is an iterative process.
(6) The capacity of neural networks to resolve complex practical problems by using a (sometimes
small) set of examples gives them an extremely wide range of applicability. Their spectrum of application
ranges from character recognition systems (used to sort out the post), signature recognition systems (used
in the banking system) and speech recognition systems, to automatic pilot and (real time) systems used to
control complex processes. This spectrum is being permanently extended and it is considered that, at least
in the near future, the connectionist paradigm will continue to raise the interest of researchers in the field
of artificial intelligence.
(7) An example of results obtained by training the network shown in Figure 4.8 can be seen in
Figure 4.9, which presents the influence of the reservoir levels and time on the water levels inside a
piezometric bore hole (F11) located on the right bank of Motru dam. It can be noted that, for the same
reservoir level, the water level inside the bore hole has dropped over time by approximately 0.50 m.
INPUT NODES OUTPUT NODE
NODE 1 – DATE NODE 1 – PIEZOMETRIC LEVEL
NODE 2 – UPSTREAM LEVEL Output 1
Input Node 2
May/1990 Jan/1993 Oct/1995 Jul/1998 Apr/2001
Input Node 1
Fig. 4.9 Diagram of influence of the reservoir levels and time on the water levels inside a piezometric
bore hole (F11) located on the right bank of Motru dam.
(8) In the monitoring of hydraulic structures, neural networks belong to the category of “black
box” models, since both the entries and the exits are known, but ignoring the intrinsic algorithm of the
neural network is generally preferred. This algorithm could be deducted from the mathematical
development of the network, but is ignored due to the low physical relevance of the mathematical formula.
4.5 Other models
(1) From amongst other statistical models that are described in the specialist literature, the
following can be mentioned: statistical lag model; statistical model with precipitation integration;
statistical model with air temperature integration; Gresz-Szalavari autoregressive statistical model;
statistical models of the discrete time series (AR, MA, ARMA, ARIMA).
(2) Hybrid models are combinations between two of the types of models described above - most
frequently between a deterministic model and a statistical model.
5. INFORMATION FLOW
(1) The dam behaviour monitoring activity must be organised in accordance with the normative
documents in force (Law No 10/1995 regarding quality in construction, Government Emergency
Ordinance No 244/2000 on dam safety, Government Decision No 766/1997 for the approval of certain
regulations regarding safety in construction), as well as the specific technical regulations in force
regarding the behaviour of structures over time and tracking the behaviour of hydraulic structures.
Analysis of the behaviour of hydraulic structures shall be carried out at several levels of competence:
(dam)- local level, territorial division-(hydrotechnical system, water branches, hydroelectric power plant
branch, etc.), central division and national level. Each level of analysis has its specific importance and
(2) In this information flow, fulfilling the UCC tasks at local level is essential for the good
operation of the entire system. Local UCC managers must immediately inform their direct supervisor
about any behavioural anomaly found, so that immediate measures can be taken to return the structure to
within acceptable risk limits, and so additional observations and measurements which are very important
in identifying the causes of the behavioural anomaly can be carried out, and, finally, in choosing the most
efficient remedy solutions.
(3) Normally, at local level (SGA – Water Management System), the following persons are involved
in decision making and the transmission of UCC information: the director of the division, hydrotechnical
system managers, independent team manages in charge of tracking the behaviour of the structures under
(4) The structure tracking department check and inspect the way in which the UCC tasks are carried
out at each hierarchical level, as well as by direct observation of the phenomena being reported. The
department shall notify the Water Directorate management, on a quarterly basis and whenever necessary,
about the activities carried out in order to monitor the behaviour of the structures under their management.
When necessary, the department members shall take the necessary measures to avoid or limit the negative
effects of the phenomena found, and report the results to their direct supervisor.
(5) The person responsible for tracking the behaviour of the structures shall directly monitor, by
means of on-site inspections, the behaviour of all facilities under their management once every quarter and
after every unusual event. The UCC manager shall draw up an “Annual report on the UCC activity on
SGA”, which shall include all the proposals issued by the managers of the hydrotechnical systems and
(6) The UCC manager shall also process and interpret the measurement data and the data included in
the reports submitted by the managers of the hydrotechnical systems and independent teams, and shall draw
up an annual "Report on the state of the structures being managed".
(7) The UCC manager is obliged to train the personnel taking part in structure behaviour tracking
activities in their required tasks.
(8) The system and independent team leaders shall instruct their subordinate personnel with regard to
the way their UCC responsibilities should be carried out (team leaders, people with specific responsibilities:
dam maintenance workers, hydraulic workers, mechanics).
(9) The monitoring department carry out their activity in collaboration with other departments such
as: the flood protection, water survey, production, control and facility operation departments.
(10) The protection department shall draw up the warning-alarm and local flood defence plans, and
shall make decisions and take measures they consider appropriate during high-water periods.
(11) The production department, at the proposal of the system managers and the person responsible
for monitoring the structures, shall include all remedy works carried out to ensure the good operation of
the structures in the technical plan.
(12) The water control department shall collect daily data, the water level in the reservoir,
upstream and downstream, the precipitation fallen and the temperature in the area of the structure.
(13) In accordance with the provisions of Government Decision No 638/1999 for the approval of
the Regulation on protection against flooding, hazardous meteorological phenomena and accidents
involving hydraulic structures and the Framework Standard for the provision of materials and means for
effective protection against flooding and ice, each retention structure must have an alarm-evacuation plan
and a system for informing the local authorities.
(14) The plan for warning/alarming the population and socio-economic facilities located
downstream from the reservoir in the event of an accident occurring at the hydraulic structures must be
drawn up by the owner of the facility and approved by the appropriate ministry.
This plan shall establish:
- the damage hypotheses taken into consideration when calculating the floodable areas;
- the information system, including the audible alarm system;
- the situations and decision to activate the alarm system, responsibilities relating to taking the
decision to trigger the alarm system, for the three levels of hazard;
- the routes used to communicate the decisions, responsibilities and the method for activating the
- measures to be taken when the critical thresholds are reached.
(15) The “Plan for warning/alarming the population and socio-economic facilities located
downstream from the reservoir in the event of an accident occurring at the hydraulic structures” must be
backed up by a “Plan for emergency evacuation of the population”, which falls under the responsibility of
the General Inspectorate for Emergency Situations, in accordance with the legislation in force.
(16) The passage of flash floods through the reservoir is regulated by the Reservoir Operating
Rules, which stipulate the manoeuvres to be carried out, as well as the responsibilities and decision-
(17) For atypical phenomena, there are several states depending on the gravity of the deviation
from the normal situation and the degree of risk that results from this:
- state of caution – represents a mere deviation from the normal parameters, without posing a threat to the
safety of the structures;
- state of alert– is triggered by the occurrence of discharges which cause the flooding of certain areas
and/or an imminent risk of damage or even rupture of the structure;
(18) Entering this exceptional situation triggers the action of alarming and evacuating the
population from the areas that could be affected.
- state of alarm- is triggered when phenomena whose development could pose a threat for the areas
adjacent to hydraulic structures are observed.
(19) Depending on the state found during operation of the dam, the operating personnel have
specific responsibilities for each critical state.
(20) The dam maintenance worker shall notify the SGA control department about any changes in
the behaviour of the hydraulic structure:
relative deformations: cracks, collapsing of slopes, etc.;
levels in the piezometer wells;
blockages of hydro-mechanical equipment;
rapid increase of the water level inside the reservoir.
(21) The controller on duty shall immediately inform the SGA director, the hydrotechnical
system manager, the independent team leader in charge of operating the structure and the UCC manager
within SGA about any changes found in the behaviour of the hydraulic structure. Then the SGA control
department shall inform the water branch about the situation that has occurred at the reservoir.
(22) The team leader and the UCC manager (depending on the situation that has occurred at the
reservoir) must go to the reservoir in person to validate the information supplied by the dam maintenance
(23) If the “caution” threshold has been reached by one of the MCD devices, the following
procedure shall be followed:
The team leader and UCC manager shall repeat the set of measurements and compare them
with the previous measurements.
If the new measurements fit within the “caution” range (in accordance with the tables of
critical thresholds set), the data shall be immediately sent for processing and analysis to the
SGA control department who, after their validation by the SGA director, will forward them to
the water branch; the water branch shall inform the Water Directorate management about the
situation that has occurred at the reservoir;If the phenomenon progresses towards reaching the
“alert” threshold, the SGA director and intervention team shall be summoned to the reservoir and the stock
of flood protection materials shall be prepared.
(24) If the “alert” threshold is reached:
The measures stipulated for the previous “caution” threshold shall be applied;The
programme for intensive monitoring of the behaviour of the structure shall be applied;the
management of all structure behaviour tracking operations, as well as the preparation of all
dam protection actions shall fall under the responsibility of the SGA director. If he/she cannot
be present at the reservoir for objective reasons, all operations shall be managed by the team
leader;After analysing the data received from the reservoir, the water branch shall prepare the
decision to alarm the commission for protection against flooding, hazardous meteorological phenomena
and accidents in hydraulic structures located downstream from the reservoir.
(25) If the “alarm” threshold is reached:
The measures stipulated for the previous “alert” threshold shall be applied;The SGA director
shall be present at the dam and lead all operations for protecting the structure and alarming the population
located downstream from the reservoir.
(26) If the phenomenon progresses through the three thresholds: caution-danger-alarm at a slow
pace, the decision to trigger the alarm system shall be made by the Water Directorate management through
the water branch and the SGA control department when it is evident that the “alarm” threshold will be
(27) If the phenomenon progresses very quickly or if the alarm threshold is reached without going
through the caution and danger threshold, and the failure is evident and unavoidable, the person with the
highest rank amongst the dam personnel or, in that person’s absence, the dam maintenance worker, shall
immediately trigger the alarm without having to wait for a decision to be issued by the Water Directorate,
but after consulting with the management of the local water management system (SGA).
A. Appendix 1 Standards
Item Corresponding Romanian standard Title
1 SR EN 1990:2004 Eurocode: Basis of structural design
SR EN 1990:2004/NA:2006 National Annex
SR EN 1990:2004/A1:2006 Eurocode: Basis of structural design. Amendment 1
SR EN 1990:2004/A1:2006/AC:2010
SR EN 1990:2004/A1:2006/NA:2009 Annex A2: Application for bridges. National Annex
2 SR EN 1991-1-1:2004 Eurocode 1: Actions on structures. Part 1-1: General actions. Specific
SR EN 1991-1-1:2004/AC:2009 densities, self-weight, and imposed loads for buildings
SR EN 1991-1-1:2004/NA:2006 National Annex
SR EN 1991-1-2:2004 Eurocode 1: Actions on structures. Part 1-2: General actions. Actions
SR EN 1991-1-2:2004/AC:2009 on structures exposed to fire
SR EN 1991-1-2:2004/NA:2006 National Annex
SR EN 1991-1-3:2005 Eurocode 1: Actions on structures. Part 1-3: General actions. Snow
SR EN 1991-1-3:2005/AC:2009 loads
SR EN 1991-1-3:2005/NA:2006 National Annex
SR EN 1991-1-4:2006 Eurocode 1: Actions on structures. Part 1-4: General actions – Wind
SR EN 1991-1-4:2006/AC:2010 actions
SR EN 1991-1-4:2006/NB:2007 National Annex
SR EN 1991-1-5:2004 Eurocode 1: Actions on structures. Part 1-5: General actions – Thermal
SR EN 1991-1-5:2004/AC:2009 actions
SR EN 1991-1-5:2004/NA:2008 National Annex
SR EN 1991-1-6:2005 Eurocode 1: Actions on structures. Part 1-6: General actions. Actions
SR EN 1991-1-6:2005/AC:2008 during execution
SR EN 1991-1-6:2005/NB:2008 National Annex
SR EN 1991-1-7:2007 Eurocode 1: Actions on structures. Part 1-7: General actions.
SR EN 1991-1-7:2007/AC:2010 Accidental actions
SR EN 1991-2:2004 Eurocode 1: Actions on structures. Part 2: Traffic loads on bridges
SR EN 1991-2:2004/AC:2010 National Annex
SR EN 1991-2:2004/NB:2006
Eurocode 1: Actions on structures. Part 3: Actions induced by cranes
SR EN 1991-3:2007 and machinery
SR EN 1991-3:2007/NA:2009
Eurocode 1: Actions on structures. Part 4: Silos and tanks
SR EN 1991-4:2006 National Annex
SR EN 1991-4:2006/NB:2008
3 SR EN 1992-1-1:2004 Eurocode 2: Design of concrete structures. Part 1-1: General rules and
SR EN 1992-1-1:2004/AC:2008 rules for buildings
SR EN 1992-1-1:2004/NB:2008 National Annex
SR EN 1992-1-2:2006 Eurocode 2: Design of concrete structures. Part 1-2: General rules.
SR EN 1992-1-2:2006/AC:2008 Structural fire design
SR EN 1992-1-2:2006/NA:2009 National Annex
SR EN 1992-2:2006 Eurocode 2: Design of concrete structures. Part 2: Concrete bridges.
SR EN 1992-2:2006/AC:2008 Design and detailing rules
SR EN 1992-2:2006/NA:2009 National Annex
SR EN 1992-3:2006 Eurocode 2: Design of concrete structures. Part 3: Silos and tanks
SR EN 1992-3:2006/NA:2008
4 SR EN 1994-1-1:2004 Eurocode 4: Design of composite steel and concrete structures Part 1-
SR EN 1994-1-1:2004/AC:2009 1: General rules and rules for buildings
SR EN 1994-1-1:2004/NB:2008 National Annex
SR EN 1994-1-2:2006 Eurocode 4: Design of composite steel and concrete structures Part 1-
SR EN 1994-1-2:2006/AC:2008 2: General rules. Structural fire design
SR EN 1994-1-2:2006/NB:2008 National Annex
SR EN 1994-2:2006 Eurocode 4: Design of composite steel and concrete structures Part 2:
SR EN 1994-2:2006/AC:2008 General rules and rules for bridges
SR EN 1994-2:2006/NB:2009 National Annex
5 SR EN 1997-1:2004 Eurocode 7: Geotechnical design. Part 1: General rules
SR EN 1997-1:2004/AC:2009
SR EN 1997-1:2004/NB:2007 National Annex
SR EN 1997-2:2007 Eurocode 7: Geotechnical design. Part 2: Ground investigation and
SR EN 1997-2:2007/NB:2009 National Annex
6 SR EN 1998-1:2004 Eurocode 8: Design of structures for earthquake resistance. Part 1:
SR EN 1998-1:2004/AC:2010 General rules, seismic actions and rules for buildings.
SR EN 1998-1:2004/NA:2008 National Annex
SR EN 1998-2:2006 Eurocode 8: Design of structures for earthquake resistance. Part 2:
SR EN 1998-2:2006/AC:2010 Bridges
SR EN 1998-2:2006/A1:2009 Eurocode 8: Design of structures for earthquake resistance. Part 2:
Bridges. Amendment 1
SR EN 1998-2:2006/NA:2010 National Annex
SR EN 1998-3:2005 Eurocode 8: Design of structures for earthquake resistance. Part 3:
SR EN 1998-3:2005/AC:2010 Assessment and retrofitting of buildings
SR EN 1998-3:2005/NA:2010 National Annex
SR EN 1998-4:2007 Eurocode 8: Design of structures for earthquake resistance. Part 4:
Silos, tanks and pipelines
SR EN 1998-4:2007/NB:2008 National Annex
SR EN 1998-5:2004 Eurocode 8: Design of structures for earthquake resistance. Part 5:
Foundations, retaining structures and geotechnical aspects.
SR EN 1998-5:2004/NA:2007 National Annex
SR EN 1998-6:2005 Eurocode 8: Design of structures for earthquake resistance. Part 6:
Towers, masts and chimneys
SR EN 1998-6:2005/NB:2008 National Annex
STAS 8593 – 88 River bed regulation works. Ground studies and laboratory research.
STAS 4068/1-82 Maximum water discharges and volumes. Determination of the maximum
discharges and volumes of watercourses.
STAS 4068/2-87 Maximum water discharges and volumes. Annual probabilities of maximum
discharges and volumes under normal and special operating conditions.
STAS 4273 – 83 Hydrotechnical construction. Classification into importance classes.
STAS 9269 – 89 River bed regulation works. General design requirements.
C. Normative documents and technical regulations
Item Title of the normative document Publication
1. Law No 10/1995 regarding quality in construction, with its Published in the Official Gazette, Part
subsequent modifications. I(12) of 24 January 1995.
2. Law No 481/2004 regarding civilian protection, with its Published in the Official Gazette, Part
subsequent modifications and supplementation, republished, I(1094) of 24 November 2004
with the subsequent modifications and supplementation
3. Law No 107/1996 Water law, with its subsequent Published in the Official Gazette, Part
modifications and supplementation. I(224) of 08 October 1996.
4. Government Emergency Ordinance No 195/2005 Published in the Official Gazette, Part
regarding environmental protection, approved with I(1196) of 30 December 2005.
modifications and supplementation by Law No 265/2006,
with its subsequent modifications and supplementation.
5. Law No 319/2006 on health and safety at work. Published in the Official Gazette, Part
I(646) of 26 July 2006.
6. Government Emergency Ordinance No 244/2000 Published in the Official Gazette, Part
regarding the safety of dams, with its subsequent I(633) of 06 December 2000.
modifications and supplementation, approved by Law No
7. Government Emergency Ordinance No 138/2005 Published in the Official Gazette, Part
regarding the safe operation of water accumulations of fish- I(916) of 13 October 2005.
farming, leisure-related or local use belonging to importance
categories C and D, with its modifications and
supplementation, approved by Law No 13/2006.
8. Government Decision no 766/1997 for the approval of Published in the Official Gazette, Part
certain regulations concerning quality in construction, with I(352) of 10 December 1997.
its subsequent modifications and supplementation.
9. Government Decision no 638/1999 for the approval of the Published in the Official Gazette, Part
Regulation on protection against flooding, hazardous I(385)x of 13 August 1999.
meteorological phenomena and accidents involving
hydraulic structures and the Framework Standard for the
provision of materials and means for effective protection
against flooding and ice.
10. Order no 638/420/2005 of the Minister of Administration
and Internal Affairs and the Minister of the Environment
and Water Management to approve the Regulation on the Published in the Official Gazette, Part
management of emergency situations caused by flooding, I(455) of 30 May 2005.
hazardous meteorological phenomena, accidents involving
hydraulic structures and accidental pollution.
11. Order no 115/288/2002 of the Minister of Water and
Environmental Protection and the Minister of Public
Works, Transport and Housing to approve the Published in the Official Gazette, Part
Methodology for establishing dam importance categories I(427) of 19 June 2002
12. Order no 1259/2006 of the Minister of Administration
and Internal Affairs to approve the Standards for the
Published in the Official Gazette, Part
organisation and pursuit of notification, warning, pre-alert I(349) of 18 April 2006
and alert activities in civil defence situations.