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					1. ------IND- 2011 0134 RO- EN- ------ 20110418 --- --- PROJET



  GOVERNMENT OF ROMANIA
                                                                              MINISTRY OF REGIONAL
                                                                          DEVELOPMENT AND TOURISM
                                                                                              www.mdrt.ro



                                         ORDER
                              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
modifications,
        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
Tourism,
        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

                                                       ORDER:
        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.


                                                                                                            1
                                                         MINISTER
                                                   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




                                                                                                                                      2
Prepared by: Technical University of Civil Engineering of Bucharest

                                             March 2011
                                             CONTENTS



        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




                                                                                                         3
                                           TERMINOLOGY


   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
      its structure.
      Explanatory note:
      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
           supporting frame.

   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
       natural environment.
       Explanatory notes
       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.
   Explanatory notes:
   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
   time.

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
   measure.



                                                                                                         4
     Explanatory notes:
     Measuring equipment (instrument, device) can be used individually or as part of complex systems
     such as:
        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
     assignment.

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.
    Explanatory note:
    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.
    Explanatory note
    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.

                                         ABBREVIATIONS


                                                                                                      5
       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 [1].

       (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


                                                                                                           6
early stage so appropriate measures may be taken before such phenomena threaten the safety of the
structure.

        (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
[2], [3], [4], [5], [6], [7], [8], [9].

        (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.


                                                                                                           7
        (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:
       design errors;
       structural faults;
       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).




                                                                                                                   8
       (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
methods.

       (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
consequences.

       (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
consequences.

       (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
reservoir.

        (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.


                                                                                                              9
         (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
conditions.

        (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
dam.

       1.2 Monitored parameters and specific equipment for dams made of concrete and filler
       materials



                                                                                                           10
         (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.
                                                                                          Table 1.1
       Concrete dams                Dams made of filler               Foundations
                                           materials
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
                                Turbidity                    Turbidity.

        (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.


                                                                                                            11
        (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
           environment.




                                   Core   Cladding Protective   Reinforcement   Outer jacket
                                                   jacket       fibres




                                                                                                        12
                                                                                             Core
                                                                                                        
                                                                                             Optical        Optical fibre
                                     250 Micron   125 Micron                                 cladding   
                4mm    2mm   1mm
                                                                                        Acrylic jacket
                                                                                       Buffer
                                                                                       Mechanical protection - Kevlar
                                                                                      Polyurethane outer
                                                                                      jacket
                                         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
                                                                                  unit)                     reporting



           Fig. 1.3. Typical diagram of an automatic monitoring system in the form of a chain.
       I

        (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.



                                                                                                                             13
        M – The measurement range must be sufficiently wide to cover exceptional loads or unexpected
behaviours.
        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.


                                                                                                   Table 1.2
 Parameter measured       Equipment                Requirements
                          Measurement system       F – durability
                          Measurement method            (reliability)
                                                   L – longevity                Comments
                                                   M – measurement
                                                        range
                                                   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
                              light indicators
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
Temperatures
Air and water                 Thermographs         F: moderate          These instruments can be
temperature                                        L: moderate          easily replaced.
                                                           0          0
                              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
melting                                                                 recordings
                              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


                                                                                                          14
                         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
                                                                            recordings.




         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
                                                    provided                sufficient
                         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
                                                                            sufficient.
                                                                            With the possibility of
                                                                            carrying out automatic
                                                                            measurements and data
                                                                            recordings.
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
                                                                            +60 °C
                                                                            Relatively easy to install.
                                                                            With the possibility of
                                                                            carrying out automatic
                                                                            measurements and data
                                                                            recordings.
Precipitation




                                                                                                           15
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
Pressures
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
                                                                           recordings.
                           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
                                                                           recordings

        2. DEFORMATIONS AND DISPLACEMENTS (DAMS AND ADJACENT AREAS)
Geodetic measurements




                                                                                                          16
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
                                                                             deformations.
                                                                             All data and indications
                                                                             relating to assessment
                                                                             measurements and methods
                                                                             must be filed (included in a
                                                                             database)




           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
                                                                             sedimentation phenomena
                                                                             taking place in the
                                                                             reservoir.




                                                                                                             17
                         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
                                                        established
                                                        depending on the
                                                        situation
                                                    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
                                                      circumstances;
                                                      necessary in
                                                      combination with
                                                      triangulation
                         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.
                                                       pendulums
           1                         2                           3                           4
                         Polygons                   F, L, M, P : need to be    Very accurate
                                                         established           measurements.
                                                         depending on the      Combination with
                                                         situation             triangulation and
                                                    R: absolutely necessary    pendulums is absolutely
                                                         in combination with   necessary.
                                                         triangulation and
                                                         pendulums
Instruments




                                                                                                              18
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:
                                                     - additional
                                                       measurement
                                                       equipment;
                                                     - combination with
                                                       triangulation,
                                                       polygons, alignments,
                                                       extensometers
                          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
                                                     measurement
                                                     equipment;
                                                     - combination with
                                                     triangulation, polygons,
                                                     extensometers
                          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
                                                         installation)          inclinometer-pipe
                                                     R: required, together
                                                         with levelling




            1                        2                          3                            4




                                                                                                             19
                            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
                                                                              measuring fluid.
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
                                                       geodetic               horizontally.
                                                       measurements or        If the readings are outside
                                                       metric tape            the measurement scale, the
                                                       measurements           string itself can extend or
                                                                              contract.
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
                                                      extensometer in
                                                      several comparable
                                                      locations;
                                                    - dividing the total
                                                      length into several
                                                      sections;
                                                    - combination with an
                                                      inverted pendulum or
                                                      levelling
                            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:
                                                    - installing
                                                      extensometers in
                                                      several comparable
                                                      locations;
                                                    - dividing the total
                                                      length into several
                                                      sections



                                                                                                              20
             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
                                                      installing
                                                      extensometers in
                                                      several comparable
                                                      locations.
                            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
                                                                               time.
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.
                                                         levelling

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.
                                                                               Automatic measurement
                                                                               and recording possibilities.
            1                          2                        3                            4




                                                                                                              21
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
                                                     instruments
                                                   - other types of
                                                     instruments, for
                                                     comparison
                                          3. INFILTRATION
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
                           downstream).
                           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
                                                                               infiltrations.
                                                                               Automatic measurement
                                                                               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.
                           magneto-inductive
                           measurements (flow
                           speed measurements)
           1                          2                         3                            4




                                                                                                                22
                         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
                                                                                ensured
                         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
                                                                                absolutely necessary.
                                                                                Automatic measurement
                                                                                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
                                                     groups                     hole.
                                                                                Automatic measurement
                                                                                and recording possibilities.



                                                                                                                23
          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,
                                                                         stones, etc.
                                                                         Permanent airing must be
                                                                         ensured.
                                                                         Checking the good
                                                                         operation of the equipment
                                                                         by flushing (repeated
                                                                         washing).
                    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
                                                                         absolutely necessary.
                                                                         Automatic measurement
                                                                         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
                                                                         hole.
                                                                         Automatic measurement
                                                                         and recording possibilities.

          1                    2                         3                            4


                                                                                                         24
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.
                                                                                Automatic measurement
                                                                                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.
                                                      values expected
                                                 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
                           Ultrasounds               geophysical
                           Infrared land surveys     methods
                           Diagraphy

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
                                                     situation                  conditions.
                                                     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
                                                     tests
                             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
                                                     situation                  dam
                                                     R: necessary; large
                                                     number of tests



            1                           2                       3                            4



                                                                                                                25
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
                            circulation.                provided
                                             5. MISCELLANEA
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
                            (records the
                            accelerations over time)                            interpretation of the
                                                                                results must be carried
                                                                                out by specialists.




      2. COMPULSORY REQUIREMENTS FOR THE MONITORING SYSTEM

        2.1. General elements


                                                                                                                26
        (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 [8] 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.

                                                                                      Approvals,
                             Level IV               Public authority          authorisations or licences
                                                                                  for safe operation



                                                                               Safety assessments at
                                                        Experts                    pre-established
                             Level III              (employed by the            intervals (5-7 years)
                                                        owners)

                                                                               Analysis and interpretation of
                                                  Experienced specialists             measurements
                                                                               Annual technical inspections
                              Level II
                                                                                  Annual safety reports

                                                                                Visual inspections
                                                                               MCD measurements
                                                     Local ECC team           Equipment manoeuvers
                              Level I                   (owner)                          +
                                                                              Processing and primary
                                                                                  interpretation




         Fig. 2.1 Organisation of the dam behaviour monitoring system in countries having a tradition
                                        (according to Biedermann [8]).
    (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.


                                                                                                                27
    (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
       specific tasks;
      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
       owner;
      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.




                                                                                                               28
    (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
1(1.2).

       (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.




                                                                                                         29
                                                     Direct pendulum            Rockmeter
                                                     Inverted pendulum          Interstitial pressure cells
                                                     Extensometer               Total pressure cells
                                                     Telethermometer            Telelimnimeter
                                                     Fault spillway             Topographic and geodetic
                                                     Clinometer             markers
                                                                                Accelerographs
                                                     Deformetric bolts




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.




                                                                                  Table 2.1
                Parameters monitored inside the      Types of instruments
                            dam body
               Horizontal displacements              Direct and inverted pendulums


                                                                                                              30
             Settling                               Fixed-point monitoring network
             Deformations and stresses in the       Concrete-embedded        deformation
             concrete                               transducers
             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
             Under-pressure

                                                                               Table 2.2
                 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
             Infiltration                           displacements)
                                                    Regulating spillways. Flow meters

                                                                             Table 2.3
                Crit        Type of instrument            Installed     In operation
                eria                                    (1970-1978)       in 2006
                no.
                  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
                       Water telethermometer
                       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.




                                                                                           31
                                                   Bypass
                                                   gallery
                                                                                     R.F.S.
                                                                            Rs 21


                                                    Water
                         Cofferdam                  inlet




                                                                        DIsSIPATOR
                                     Bottom drain

                                     C.H.E.inlet
                                                                                                 Tail race

                                                                        C.H.E.
                                                                                                                          KEY
                                                                                                                          Fixed stationary pilaster
                                                                                                                          Stationary pilaster
                                                                                                                          Study marker
                                                                                                 Reservoir                Fundamental levelling
                                                              Rs 4
                                                                                                 bypass road              marker
                                                                 R.E.D.                                                   Fixed spatial marker




                       Fig. 2.3. Gura Raului dam – Layout with the geodetic network.

                                                                                     LONGITUDINAL SECTION
                                                                                         DOWNSTREAM VIEW
                                              Rs4            Pendulum                         Pendulum                    Pendulum          Rs21
                                                                                                             Pendulum




                   BLOCK 7                                                     BLOCK 18



                                                                                                                            HYDROMETERS

                                                                                                                        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



                                                                                                                                                        32
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
Chapter 1(1.2).

   (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




                 Inclinometric joint

                           Rockmeter
                        Dilatometers
                           Clinometer
                     Telethermometer
                       Accelerograph                                   Dam made of filler
     Topographic and geodetic markers
                                                                       materials with a reinforced
            Interstitial pressure cells
               Total pressure cells
                                                                       concrete mask
               Filling extensometrer
       Inclinometer and vertical settling
                               device

                           Piezometer
                      Telelimnimeter




           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.




                                                                                    Table 2.4
                            Parameters monitored at          Types of instruments
                          dams made of filler materials



                                                                                                      33
               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
generally smaller.

        (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).

                                                                                    Table 2.5
                 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
                                           microtriangulation
                                           and accurate levelling
             Relative displacements of the inclinometer columns
             dam body                      made by SINCO
                                           (USA)
                                           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


                                                                                                    34
                                      transducers made by (38 in operation)
             Total pressures and pore TELEMAC (France) 99 pore water cells (48
             pressures in the core                        in operation)

                                             Accelerometers                          5
                                             Seismograph                             1

             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.




                                                                           Key:
                                                                           Rock pilaster
                                                                           Berm pilaster
                                                                           Boundary stone with spatial study marker
                                                                           Boundary stone with bolt (level study)
                                                                           Orientation marker
                                                                           Supporting level marker
                                                                           Transport level marker




                        Fig. 2.6. Siriu dam – Location of the geodetic equipment.
                       Right bank                                       Left bank




                                                         Gallery G10           Gallery G5

                                                     Gallery G11

                                                                                    Gallery G3
                                                                        Gallery G4




                                                                                                                      35
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.




                                                                                                          36
        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.


                                                                    MONITORING




                                                                                        OBSERVATIONS




                                                                                                                   INSPECTIONS AND
                                             MONITORING




                                                                                                                                     - auxiliary structures (spillways, drains, hydroelectric power plant, etc.);
                                                                                           VISUAL




                                                                                                                   TESTS
                                                                              Reports




                                                                                                         Reports
                                      Data




                                                                                                                                     - dam, foundation, reservoir and its slopes;
                      Manual                                    Automated




                                                                                                                                     - behaviour tracking system;
                                                                                                                                     - warning-alarm system.
                                                                                                                                     Items being monitored:
                        Acquisition                           Acquisition

                      Transmission                          Transmission

                       Processing                           Processing

                       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
                                               system.

                                        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
       stage;
   -   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
       surveys.


                                                                                                                                                                                                                    37
       (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
extreme values.

       (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
requirements, etc.);
       - 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.).




                                                                                                           38
        (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
situations.
                                                                                     Table 3.1
          Parameters being          Type of device     M.U.              Frequency
  Ite          tracked
  m                                                               normal         exceptional
  No

 1        Reservoir level            Hydrometer            mdM       1/day            1/day
 2        Precipitation              Pluviometer           mm/da     1/day            1/day
                                                           y
 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
                                     holes
 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
          displacements
 9        Absolute                   Geodetic network       mm       2/year
          displacements
 10       Reservoir clogging         Bathymetric profiles   mdM      3-5 years        After     flash
                                                                                      flooding
 11       Downstream river bed Bathymetric profiles         mdM      3-5 years        After     flash
          modifications                                                               flooding
 12       Visual observations                                        daily            Special
                                                                                      programme

          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:

                                                                                 Table 3.2
           Frequency            Who carries them out         Who checks       Where they are recorded
                                                                them
     A       Daily              The entire personnel          Foremen                Shift register
     B      Weekly                   Foremen                UCCH manager             Shift register
     C      Monthly               UCCH manager                Operating             Events register



                                                                                                        39
                                                         manager
   D         Yearly    A committee appointed by the        The                      PV
                             management                 management

- 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
descriptions.

        (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
management.


           3.3. Content of annual reports and summarising reports relating to the behaviour of the
facility

        (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:



                                                                                                        40
      1. General data
    Name, type of structure, location
    Administrative affiliation
    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
   Organisational diagram
   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
    Water level
    Precipitation
    Air (water) temperature
    Flash flooding registered
    Seismic stresses
     Changes caused by clogging, erosion
     Operation of spillways
     Characterisation of the stresses compared to those applied during the previous period and design
stresses
     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)
   Spillways
   Situation of the upstream and downstream channels
   Condition of the access routes


        6. Hydro-mechanical equipment in the retention field
    Components
    Main technical characteristics
    Condition of the structure, activating systems, seals, anti-corrosion protection, position tracking and
signalling systems


                                                                                                        41
   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

       9. Conclusions
       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
studies, etc.




                                    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.




                                                                                                       42
        (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
developed.

          (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 .




                                                                                                              43
                                                                     Span of valley to the edges = 170 m       50m
                                                            50m




                                                                                                                     Dam height = 140 m
Fig. 4.1. Gordon dam ( H  140 m,
Australia)     –   Finite element
digitisation diagram
                            Radial displacements
                                    (mm)




                                                                   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 +
     inverted).


       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


                                                                                                                                          44
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
Fourier transform.

       (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
measurement errors.

        (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
the relationship:
                                              f1  Z   a1 Z  a2 Z 2  a3 Z 3  a4 Z 4 ,              (4.3)


            NNR  NH
where Z               ,      NNR being the elevation level of the normal retention level, NH – the level
               Hb
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:




                                                                                                            45
                                                     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)


where:
         a5   cos 
         a6    sin 
         a7   2  cos 
         a8   2  sin 
                  Di  D0                           Di  D0
         S  2           (rad) or:    S  360              (degrees sexg).
                  365,25                            365,25

         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)

              Di  D0
where T                (years); D0 - reference date of the model (dam is first activated); Di - measurement
              365,25
date.

        (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 
                                                                                                                      (4.8)
                                     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


                                                                                                                        46
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 
                                                                                                      (4.10)
                               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.




                                                                                                          47
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.




                                                                                                      48
                                                                                                                         External factors (Actions, Causes)




                            Level [mdM]

                                                                                                                                        Time [years]
                                                               Reservoir level
                                                                                                                                                                        ptan -1 = 0.1
                                                               Average daily air temperature


                                              UM = “mm”                                                                Chronological series of the modelled parameter
                                          Modelled parameter




                                                                                                                                          Time [years]
                                                                     Calculated
                                                                     Measured
                                                                     Smoothing with averaging of the closest values
                                                                     Irreversible component




 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
  Influences




                                                                                                               Time [years]
               Hydrostatic influence
               Influence of air temperature
               Irreversible influence
               Measured parameter




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.



                                                                                                                                                                                        49
                                                Statistical validity limit.

                                                                                           UM = “mm”




                           Measured parameter




                                                        Calculated parameter




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
noted.

        (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
behaviour limits.

       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
network
       (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.




                                                         Summation            Activation




                                                                                                         50
                                                     Network Design

                                                        Inputs




                                                      Outputs




 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.



                                                                                                               51
                                               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



                                                                                                                       52
branch, etc.), central division and national level. Each level of analysis has its specific importance and
responsibilities.


        (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
their management.


        (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
independent teams.


        (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.




                                                                                                           53
       (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
alarm system;
       - 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-
making bodies.

       (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.


                                                                                                           54
   - 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.;
                infiltration rates;
                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
worker.

          (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.


                                                                                                           55
        (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
reached.

        (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
  no.
 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




                                                                                                                    56
    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
                                  National Annex
    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
                                  National Annex
    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
                                  testing.
    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



                                                                                                           57
         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



      B. Standards

        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
No
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
      466/2001, republished
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.



                                                                                                               58
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
      NTLH 021-2002

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.




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