INSTRUMENTATION AND MONITORING OF DAMS & RESERVOIR

7/27/2019 INSTRUMENTATION AND MONITORING OF DAMS & RESERVOIR.

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NATIONAL INSTITUTE OFTECHNOLOGY, KARNATAKA

2013

Instrumentation and

Monitoring of Dams

& ReservoirSeminar Report

SUJAY RAGHAVENDRA. N

Reg no: 12WR10F2

ndsem M.Tech (WREM)

Department of Applied Mechanics and Hydraulics

NITK Surathkal.

S U R A T H K A L , M A N G A L O R E - 5 7 5 0 2 5


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Table of Contents

1. Introduction ...................................................................................................32. Purpose and Scope ........................................................................................ 33. Instrument: Types and Usage.........................................................................4

3.1 Movements ........................................................................................................................... 5

3.2 Pore Pressure and Uplift Pressure..................................................................................... 9

3.3 Water Level and Flow....................................................................................................... 11

3.4 Seepage & Leakage Flows ................................................................................................ 11

3.5 Water Quality.................................................................................................................... 15

3.6 Temperature ..................................................................................................................... 15

3.7 Crack and Joint Size .......................................................................................................... 16

3.8 Stress and Strain ............................................................................................................... 16

3.9 Seismic Loads ................................................................................................................... 17

3.10 Weather ............................................................................................................................ 17

4. Frequency of monitoring.............................................................................. 175. Adequacy of Instrumentation and Monitoring. ............................................ 186. Automated Data Acquisition ........................................................................ 187. CONCLUSIONS................................................................................................. 198. REFERENCES ................................................................................................... 19


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1. INTRODUCTION.At present, the dam safety monitoring information management system and the expert systemfunction become increasingly powerful. But India is still in the middle or even lower level

compared with developed countries, so the need for a dedicated automatically monitoring system

using the advanced network technology, database security technology, security monitoringtechnology theory, is urgent. The system will automatically monitor the dam safety, analyze thereal-time measured data and manually observed data, monitor the real-time dam operating status,

and make the accurate, efficient assessment and decision to ensure the dam safety.Instrumentation consists of the various electrical and mechanical instruments or systems used to

measure pressure, flow, movement, stress, strain, and temperature. Monitoringis the collection,reduction, presentation, and evaluation of the instrumentation data. Instrumentation and

monitoring are tools that must be used with a vigilant inspection program to continually evaluatethe safety of dams.

2. PURPOSE AND SCOPE.The purpose of instrumentation and monitoring is to maintain and improve dam safety byproviding information to

Evaluate whether a dam is performing as expected. Warn of changes that could endanger the safety of a dam.

The causes of dam failures and incidents have been catalogued (ASCE 1975 and 1988, Jansen

1980, National Research Council 1983, ICOLD 1992). The common causes of concrete damfailures and incidents are:

Overtopping from inadequate spillway capacity or spillway blockage resulting in erosionof the foundation at the toe of the dam or washout of an abutment or adjacent

embankment structure; Foundation leakage and piping in pervious strata, soluble lenses, and rock

discontinuities; and

Sliding along weak discontinuities in foundations.The principal causes of embankment dam failures and incidents are:

Overtopping from inadequate spillway capacity, spillway blockage, or excessivesettlement resulting in erosion of the embankment;

Erosion of embankments from failure of spillways, failure or deformation Of outletconduits causing leakage and piping, and failure of riprap;

Embankment leakage and piping along outlet conduits, abutment interfaces, contacts withconcrete structures, or concentrated piping in the embankment itself;

Foundation leakage and piping in pervious strata, soluble lenses, and rock discontinuities; Sliding of embankment slopes due to overly steep slopes, seepage forces, rapid

drawdown, or rainfall;

Sliding along clay seams in foundations; Cracking due to differential settlements; and Liquefaction.


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Instrumentation and monitoring, combined with vigilant visual observation, can provide earlywarning of many conditions that could contribute to dam failures and incidents. For example,

settlement of an embankment crest may increase the likelihood of overtopping; increasedseepage or turbidity could indicate piping; settlement of an embankment crest or bulging of

embankment slopes could indicate sliding or deformation; inelastic movement of concrete

structures could indicate sliding or alkali-aggregate reaction. Conversely, lack of normallyexpected natural phenomena may also indicate potential problems. For example, lack of seepagein a drainage system could indicate that seepage is occurring at a location where it was not

expected or contemplated by the designer.

Instrumentation and monitoring must be carefully planned and executed to meet definedobjectives. Every instrument in a dam should have a specific purpose. If it does not have a

specific purpose, it should not be installed or it should be abandoned. Instrumentation for long-term monitoring should be rugged and easy to maintain and should be capable of being verified

or calibrated. Instrumentation typically provides data to:

Characterize site conditions before construction;

Verify design and analysis assumptions; Evaluate behaviour during construction, first filling, and operation of the structure; Evaluate performance of specific design features; Observe performance of known geological and structural anomalies; and Evaluate performance with respect to potential site-specific failure modes.

Installation of instruments or accumulation of instrument data by itself does not improve dam

safety or protect the public. Instruments must be carefully selected, located, and installed. Datamust be conscientiously collected, meticulously reduced, tabulated, and plotted, and must be

judiciously evaluated with respect to the safety of the dam in a timely manner. A poorly plannedprogram will produce unnecessary data that the dam owner will waste time and money collecting

and interpreting, often resulting in disillusionment and abandonment of the program.

3. INSTRUMENT: TYPES AND USAGE.A wide variety of devices and procedures are used to monitor dams. The features of dams and

dam sites most often monitored by instruments include:

Movements (horizontal, vertical, rotational and lateral) Pre pressure and uplift pressures Water level and flow Seepage flow Water quality Temperature Crack and joint size seismic activity weather and precipitation stress and strain


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3.1. Movements.

Movements occur in every dam. They are caused by stresses induced by reservoir water pressure,unstable slopes (low shearing strength), low foundation shearing strength, settlement

(compressibility of foundation and dam materials), thrust due to arching, expansion resulting

from temperature change, and heave resulting from hydrostatic uplift pressures.

They can be categorized by direction:

a) Horizontal or translational movement commonly occurs in an upstream downstreamdirection in both embankment and concrete dams. It involves the movement of an entire dammass relative to its abutments or foundation. In an embankment dam, instruments commonly

used for monitoring such movement include:o Extensometers, including multi-point extensometerso Inclinometerso Embankment measuring pointso Shear stripso Structural measuring pointso Time-domain reflectometry (TDR)

Installation of simple measuring points is illustrated in Figure 3.1.1, a and b, a simple crackmonitoring system is shown in Figure 3.1.2, a, and inclinometer systems and plots are shown in

Figures 3.1.3ac

Fig 3.1.1 a


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Fig 3.1.1, b

Fig. 3.1.2, a


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Fig 3.1.2, b Fig 3.1.3, a

Fig 3.1.3, c

Fig 3.1.3, b

For a concrete dam or concrete spillway, instruments for monitoring horizontal movements mayinclude:

Crack measuring devices

Extensometers, including multi-point extensometers Inclinometers Structural measuring points Tape gauges Strain meters Plumb lines Foundation-deformation gauges Tilt meters


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b) Vertical movement is commonly a result of consolidation of embankment or foundationmaterials resulting in settlement of the dam. Another cause is heave (particularly at the toe of

a dam) caused by hydrostatic uplift pressures.

In an embankment dam, vertical movements may be monitored by:

Settlement plates and sensors Extensometers Embankment survey monuments

Structural measuring points Inclinometer casing measurements

In a concrete dam or concrete spillway, vertical movement monitoring devices may include: Settlement sensors

Extensometers A GPS monitoring system

Structural measuring points Foundation-deformation gauge

c) Rotational movementis commonly a result of high reservoir water pressure in combinationwith low shearing strength in an embankment or foundation; it may occur in eithercomponent of a dam.

This kind of movement may be measured in either embankment or concrete dams byinstruments such as:

Extensometers Inclinometers

Tilt meters Surface measurement points

Crack-measurement devices Electro-level beam sensors

Foundation-deformation gauges Plumb lines (concrete only)

d) Lateral movement(parallel with the crest of a dam) is common in concrete arch and gravitydams. The structure of an arch dam causes reservoir water pressure to be translated into ahorizontal thrust against each abutment. Gravity dams also exhibit some lateral movement

because of expansion and contraction due to temperature changes. These movements may bedetected by:

Structural measurement points Tilt meters

Extensometers Crack-measurement devices

Plumb lines Strain meters

Stress meters Inclinometers

Joint meters Load cells


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3.2 Pore Pressure and Uplift Pressure.

A certain amount of water seeps through, under, and around the ends of all dams. The water

moves through pores in the soil, rock, or concrete as well as through cracks, joints, etc. Thepressure of the water as it moves acts uniformly in all planes and is termedpore pressure. The

upward force (called uplift pressure) has the effect of reducing the effective weight of thedownstream portion of a dam and can materially reduce dam stability. Pore pressure in an

Embankment dam, a dam foundation, or an abutment reduces that components shear strength. Inaddition, excess water, if not effectively channelled by drains or filters, can result in progressive

internal erosion (piping) and failure.

Pore pressures can be monitored with the following equipment

Piezometerso Electricalo Open wello Pneumatico Hydraulico Porous tubeo Slotted pipe

Pressure meters and gauges Load cells.

Pore-pressure measurements and monitoring can supply critical information regarding the overallstability of an embankment dam following a major earthquake.

Simple Piezometers may resemble the illustration in Figure 3.2.1.a&b ; basic observation well isshown in Figure 3.2.2.

Fig 3.2.1, a Fig 3.2.1, b


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Fig 3.2.2

Observation wells are usually vertical pipes with a slotted section at the bottom or a tube with a

porous tip at the bottom. They are typically installed in boreholes with a seal at the surface toprevent surface water from entering the borehole. The depth to the water level is measured bylowering an electronic probe or weighted tape into the pipe.

Observation wells are appropriate only in a uniform, pervious material. In a stratified material,

observation wells create a hydraulic connection between strata. As a result, the water level in thewell is an ambiguous combination of the water pressure and permeability in all strata intersected

by the borehole. Observation well data may lead to erroneous conclusions regarding actual waterpressures within the dam and foundation.

Open Standpipe Piezometers.Open standpipe piezometers are observation wells with subsurface seals that isolate the strata to

be measured. Open standpipe piezometers are also known as Casagrande-type piezometers and,in concrete dams, as pore pressure cells. The seals are usually made of bentonite clay or cement

grout and care must be taken during installation to develop a good seal. Riser pipe joints shouldbe watertight to prevent leakage into or out of the pipe, which could change the water level in the

pipe. The top of the standpipe should bevented and the inside diameter should be greater than about 8 mm (0.3 inch) to be self deairing.

A common version of the open standpipe piezometer is a wellpoint, which is a prefabricatedscreened section and riser pipe that is pushed into place. If the screened section is not adequately

sealed, it will act like an observation well rather than a piezometer.The sensing zone (screened length or porous tip) of observation wells and open standpipe

piezometers is susceptible to clogging, which can increase lag time or result in failure of theinstrument. This susceptibility can be diminished by a properly designed filter pack that meets

filter criteria with the surrounding soil and properly sized perforations that are compatible withthe filter pack. Open standpipe piezometers are the standard against which all other piezometers

are judged. They are simple, reliable, inexpensive, and easy to monitor.


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3.3Water Level and Flow.Flows are often computed from knowledge of the dimensions of the outlet works and the depth

of flow in the outlet channel or pipe.For most dams, it is important to monitor the water level in the reservoir and the downstream

pool regularly to determine the quantity of water in the reservoir and its level relative to theregular outlet works and the emergency spillway.

The water level is also used to compute water pressure and pore pressure; the volume of seepageis usually directly related to the reservoir level. It is also important to establish the normal or

typical flow through the outlet works for legal purposes.Water levels may be measured by simple elevation gaugeseither staff gauges or numbers

painted on permanent, fixed structures in the reservoiror by complex devices that sense waterlevels.

Staff gages are the simplest method for measuring reservoir and tailwater levels. Staff gages are

reliable and durable. For automated monitoring, a float and recorder, ultrasonic sensor, bubbler,

or one of the other instruments discussed below is necessary.Water level gages can be used to measure flow in rivers (e.g. minimum instream flow), when therelationship between river flow and river stage is known. Stream bed erosion or sedimentation

can change the calibration and cause inaccurate measurements. Water level gages used for flowmeasurements in channels with moveable beds should be periodically re-calibrated.

3.4Seepage & Leakage Flows.Seepage must be monitored on a regular basis to determine if it is increasing, decreasing, orremaining constant as the reservoir level fluctuates. A flow rate changing relative to a reservoir

water level can be an indication of a clogged drain, piping or internal cracking of theembankment.


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Seepage may be measured using the following devices and methods:

Weirs (any shape such as V-notch, rectangular, trapezoidal, etc.) Flumes (such as a Parshall flume) Pipe methods Timed-bucket methods Flow metersExamples of weirs, flumes, and bucket measuring installations are illustrated in Figures3.4.1a&b, 3.4.2, and 3.4.3.

Fig. 3.4.1, b

Fig. 3.4.1, a

Fig.3.4.2


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Fig 3.4.3

WeirsWeirs are usually metal or plastic plates with a notch in the top edge. They are installed in a

ditch, gutter, pipe, or in manholes in the relief well collection system. The quantity of waterflowing through the notch is calculated by measuring the depth of water from the invert of the

notch to the upstream water surface and using the measurement in the appropriate hydraulicequation.

The notch can be triangular, rectangular, or trapezoidal. Triangular notches are appropriate for

low flows (less than about 0.05 m3/s [10 cfs]). Rectangular or trapezoidal weirs are appropriatefor larger flows. The crest of the weir should be thin enough that the nappe springs clear.

Parshall FlumesParshall flumes are specially shaped open channel sections. They consist of a converging

upstream section, a downward sloping throat, and an upward sloping and diverging downstreamsection. They are usually permanent installations made of reinforced concrete, metal, or

prefabricated fibreglass and can be sized to measure a wide range of flows. Throat widths from25 mm (1 inch) to 10 m (33 feet) are common. Standard flume dimensions are in USBR (1984).

The quantity of water flowing through the throat is calculated by measuring the depth of waterupstream and using the measurement in the appropriate hydraulic equation. Parshall flumes

should be installed level and ideally at a site free of downstream submergence.


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Parshall flumes are simple, reliable, and require little maintenance. They cause minimalrestriction to the flow channel and low head loss. The primary limitation is the relatively

expensive installation.

Calibrated Containers (Timed-bucket methods)Containers of known volume can be used to measure low flows that are concentrated and free-

falling. The flow rate is computed as the volume of the container divided by the time required tofill the container. Extremely low flow rates can be measured accurately. The maximum flow rate

is limited by the size of the container that can be manoeuvred quickly into and out of the flow orinto which flow can readily be diverted. Typically, calibrated containers are appropriate for

flows less than about 0.003 m3/S (50 gpm).Calibrated containers are reliable for low flows and are inexpensive. They have limited

application because of the requirement for a free-falling flow, they are not accurate for large

flows, and are labour intensive.

Importance of Seepage & Leakage.

The difference in water levels between the upstream and downstream sides of a dam causes

seepage and leakage. The amount of seepage or leakage is directly proportional to permeabilityand pressure. It is possible to have large flow with high pressure, large flow with low pressure,

low flow with high pressure, or low flow with low pressure.

Most of the factors that influence the amount of seepage or leakage do not change during the lifeof a project. Usually the main variable is the reservoir level, and typically seepage and leakage

volume are directly related to the reservoir level. Any change in seepage or leakage volume notrelated to reservoir level must be evaluated immediately. Significant or rapid changes in seepage

or leakage related to the reservoir level should also be investigated. An increase in seepage orleakage may be an indication of piping.

A decrease in seepage or leakage may indicate clogged drains. A decrease in seepage may also

indicate that seepage is increasing at a location other than that being measured, which could leadto piping. Cloudy or turbid seepage may indicate piping. New seeps or leaks may also be

indications of developing problems.

Another variable that affects the amount of seepage or leakage is the development of the steady-state phreatic surface in a newly constructed project. The steady-state phreatic surface can take

years, during which, a gradual increase in seepage or leakage may occur.

For dams on soluble rock foundations (e.g. gypsum or halite), seepage may increase with timedue to dissolution of the rock. In these cases a slow steady increase in seepage may indicate

developing problems.


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Water quality measurements can provide data to evaluate the dissolution of the foundation rock,the source of seepage, or piping. Common water quality measurements include field

measurements of Ph, temperature, and conductivity, and laboratory measurements of totaldissolved solids, total suspended solids, and a variety of minerals

(e.g. sodium, potassium, carbonate, bicarbonate, sulphate, and chloride).

3.5Water Quality.Seepage comes into contact with various minerals in the soil and rock in and around the dam,which can cause two problems: the chemical dissolution of a natural rock such as limestone and

the internal erosion of soil.

Dissolution of minerals can often be detected by comparing chemical analyses of reservoir waterand seepage water. Such tests are site specific; for example, in a limestone area, one would look

for calcium and carbonates; in a gypsum area, calcium and sulphates.

Other tests, such as pH, can also sometimes provide useful information on chemical dissolution.Internal erosion can be detected by comparing turbidity of reservoir water with that of seepage

water. A large increase in turbidity indicates erosion.

3.6Temperature.No temperature measurements are recommended for embankment dams. Proposed concrete

gravity and arch dams should have an array of instruments to measure internal and surfacetemperatures along a transverse plane through the maximum section. In addition, concrete arch

dams should have a string of instruments to measure reservoir temperature along the height ofthe maximum section. The data should be collected until the dam has been in satisfactory service

for several years and the temperatures stabilize and fluctuate between predictable values.

The internal temperature of concrete dams is commonly measured both during and afterconstruction. During construction, the heat of hydration of freshly placed concrete can create

high stresses which can result in cracking later. After construction is completed and a dam is inoperation, very significant temperature differentials are not uncommon, depending on the season.

For example, during winter, the upstream face of a dam remains relatively warm because ofreservoir-water temperature, while the downstream face of the dam is reduced to a cold ambient

air temperature. The reverse is true in summer.

Temperature measurements are important both to determine causes of movement due toexpansion or contraction and to compute actual movement. Temperature may be measured using

any of several different kinds of embedded thermometers or by simultaneous temperaturereadings on devices such as stress and strain meters, which allow for indirect measurement of the

temperature of the mass.


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3.7Crack and Joint Size.Movement of one side of a crack or joint in a concrete structure relative to the other side of the

joint or crack is commonly measured with reference points or crack meters. Grout or plasterpatches can be used to evaluate whether or not movement is occurring. Many variations are used.

Reference points can be scratch marks in the concrete, metal pins, or metal plates on opposite

sides of a joint or crack. The distance between the scratch marks is measured with a micrometeror dial gage to determine movement. Sometimes three points are used in a triangle to measure

both horizontal and vertical movement.

Crack meters are commercially available devices that allow movement in two directions to bemeasured. A common device consists of two plastic plates. One plate is opaque and contains a

grid. The other plate is translucent and contains a set of cross hairs. One plate is fixed on eachside of the crack or joint with the cross hairs set over the centre of the grid. Movement is

measured by noting the location of the cross hairs with respect to the grid. A variety of other

crack meters including Carlson and vibrating-wire sensors, dial gages, and mechanics feelergages may be used to measure movement of cracks.

3.8Stress and Strain.Measurements to determine stress and strain are common in concrete dams and, to a lesserextent, in embankment dams. The monitoring devices previously listed for measuring dam

movements, crack and joint size, and temperature are also appropriate for measuring stress andstrain. Monitoring for stress and strain permits very early detection of movement.

Earth pressures within fill and against concrete structures are commonly measured with earth

pressure cells. These are also known as total pressure cells. They consist of two flexiblediaphragms sealed around the periphery, with a fluid in the annular space between the

diaphragms. Pressure is determined by measuring the increase in fluid pressure behind thediaphragm with pneumatic or vibrating-wire sensors. Earth pressure cells should have similar

stiffness as the surrounding soil to avoid inaccurate measurements of in-situ stress caused byarching.

Soil pressures against structures can also be measured with a Carlson-type cell. It consists of a

chamber with a diaphragm on the end. Deflection of the diaphragm is measured by a Carlson-type transducer and is converted to stress. Stress in concrete structures can be measured with

total pressure cells or Carlson-type cells designed to have a stiffness similar to concrete. It can

also be measured by overcoring.

A variety of mechanical and electrical strain gages are used to measure strain in concrete

structures. Some of the instruments are designed to be embedded in the dam during constructionand others are surface mounted following construction. Strain gages are often installed in groups

so that the three-dimensional state of strain can be evaluated.


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3.9Seismic LoadsSeismic strong motion instrumentation records, acceleration from earthquake shaking are the

data that are used to evaluate the dynamic response of dams. Seismic acceleration and velocityare usually recorded with strong-motion accelerographs. These devices typically consist of three

mutually-perpendicular accelerometers, a recording system, and triggering mechanism. Toprevent accumulation of unwanted data, the instruments are usually set to be triggered at

accelerations generated by nearby small earthquakes or more distant, larger earthquakes. Theyare expensive, especially considering that multiple instruments are necessary to record dynamic

response at several locations on a structure, a foundation, or abutments. The devices must beproperly maintained, so that they operate if an earthquake occurs.

Seismic measuring devices record the intensity and duration of large-scale earth movements such

as earthquakes.. It may or may not be necessary for a private dam to contain seismic devicesdepending upon the areas seismic risk. Seismic instruments can also be used to monitor any

blasting conducted near a dam site.

3.10 Weather.Monitoring the weather at a dam site can provide valuable information about both day-to-day

performance and developing problems. A rain gauge, thermometer, and wind gauge can be easilypurchased, installed, maintained, and monitored at a dam site.

4. FREQUENCY OF MONITORING.The frequency of instrument readings or making observations at a dam depends on severalfactors including:

o The relative hazard to life and property it representso Its height or overall sizeo The relative quantity of water impoundedo The relative seismic risk at the siteo Its ageo the frequency and amount of water level fluctuation in the reservoir.

In general, as each of the above factors increases, the frequency of monitoring should increase.

For example, very frequent (even daily) readings should be taken during the first filling of areservoir, and more frequent readings should be taken when water levels are high and after

significant storms and earthquakes. As a rule of thumb, simple visual observations should bemade during each visit to the dam and not less than monthly. Daily or weekly readings should be

made during the first filling, immediate readings should be taken following a storm orearthquake, and significant seepage, movement, and stress-strain readings should probably be

made at least monthly.


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5. ADEQUACY OF INSTRUMENTATION AND MONITORING.The last step should be to assess whether the instrumentation and monitoring program is

sufficient to evaluate if a dam is performing as expected and warn of developments that could

endanger the safety of the dam. The evaluation should include answers to the following three

questions.1) Are the type, number, and location of instruments proper for the behaviour being

monitored?

2) Is the frequency of readings appropriate?3) Are the data being collected, processed, and evaluated in a timely and correct manner?

The licensee's responsible engineer should evaluate the adequacy of instrumentation and

monitoring for each set of data. Staff will evaluate the adequacy of instrumentation duringannual Operation Inspections.

If there is a discrepancy between the measured and expected behaviour of the dam, it may

indicate that data do not adequately represent the behaviour of the dam, or that conditions existthat were not accounted for in the expected behaviour. In either case it is often useful to performfield investigations and install additional instrumentation to evaluate the behaviour.

If trends or inter-relationships between data are not clear, it may be appropriate to take more

frequent measurements or collect additional complementary data.

If data are not being processed and evaluated in a timely and correct manner, personnel involvedin the instrumentation and monitoring program should be reminded, and further trained if

necessary, in the importance of each phase of the program and the potential impacts with respectto dam safety. A dam safety program is inadequate if the performance of a dam is not

understood. Instrumentation provides the means for that understanding.

6. AUTOMATED DATA ACQUISITIONAutomated data acquisition systems (ADAS) have evolved significantly over the last 10 Years. ADAS can range from the simple use of a datalogger to collect data from a few instruments tocomputer based systems that collect, reduce, present, and interpret data from a network of

hundreds of different instruments. Most types of water level, water pressure, seepage, leakage,stress, strain, and temperature instrumentation can be readily monitored. Some types of

instrumentation such as movement surveys and probe inclinometers cannot be automated.

Advantages of automated data acquisition include: reduced manpower costs for collecting data,remote collection of data, and data collection in electronic format suitable for computer

reduction, analysis, and printout. Rapid notification of potentially hazardous performance andincreased frequency of measurements can be taken on demand.


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Disadvantages include high initial costs and complex equipment. By far the greatestdisadvantage is that visual observations normally made during routine manual data collection

will not be made.

An ADAS usually consists of one or more solar-powered remote monitoring units (RMUs)

located on the dam connected to key instruments to be automated. The RMUs communicate viaradio, hardwire, or cell phone with a central network monitora conventional desktop PC withvendor-supplied interface and communication software to provide access to the on-site RMUs by

remote users. Typically, the monitor is located onsite; however, it can be located at a remotelocation (such as a district or administration building). Instrument readings are stored in memory

for either manual or automatic downloading for plotting and tabular reporting.

7. CONCLUSIONS. Instrumentation monitoring program established at one dam may not be appropriate at

another dam Each project be independently evaluated. Monitoring performance with instruments & measurements permits comparison of

constructed reality with design estimates & may help explain differences between them.

Credibility of instrumentation data is important if decision makers have to make costlydecisions on basis of instrument results.

A number of advantages of instrumentation have not been mentioned but focus was onpredicting performance during first filling- the most important time in life of dam.

8. REFERENCES. Dam safety Guidelines. Part 4: Investigations, monitoring & surveillance of dams.,

Auckland Regional Council.

Engineer manual: 1110-2-1908, Instrumentation of embankment dams and levees.,Department of the army. U.S. Army corps of engineers

Instrumentation and Monitoring Guidelines, Texas commission on environmental quality.

Documents

INSTRUMENTATION AND MONITORING OF DAMS & RESERVOIR