luis eduardo magalhƒes - lajeado hydroelectric power

LUIS EDUARDO MAGALHÃES - LAJEADO HYDROELECTRICPOWER PLANT ON THE TOCANTINS RIVER

Author: Irene Hahner

Main Brazilian Dams III

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LUIS EDUARDO MAGALHÃES - LAJEADO HYDROELECTRICPOWER PLANT ON THE TOCANTINS RIVER

1. INTRODUCTION

1.1. GeneralThe Luis Eduardo Magalhães - Lajeado Hydroelectric

Power Plant, in the Tocantins River, State of Tocantins,has been in commercial operation since 2001 and hasthe objective of attending the increasing energy demanddefined by the markets of the Brazilian interconnectedsystem and, particularly, in the North-South axis, withpoles at the Federal District, the States of Tocantins andGoiás, and the Southeast region.

The installed power is 902.5 MW and the firm energyis 4,468,476 MWh/year. It is dedicated to the use of thecompanies, in proportion to the participation of eachcompany in the formation of the Concessionaire, atpresent:• REDE Lajeado Energia S.A 45.35%• EDP Lajeado Energia S.A 27.65%• CEB Lajeado Energia S.A 20.00%• Paulista Lajeado Energia S.A 7.00%

The Contract of the Concession establishes that 75%of the energy generated should be directed to the publicservice distribution utilities, and 25% of the energygenerated shall be marketed with the status of anindependent producer, a condition that pertains to theEDP Lajeado Energia S.A.

The power plant is situated in the Tocantins - Araguaiahydrographical basin, in the middle stretch of theTocantins River, in the Municipalities of Miracema doTocantins (ME) and Lajeado (MD), both in the State ofTocantins (see Figure 1).

In 1972 Eletrobrás commenced the inventory of the

Tocantins River with the objective of mapping thepossibilities for its hydroelectric development. Two yearslater, the responsibility for the project was passed on tothe newly created Eletronorte, which published the finalstudies of this inventory in 1987, already contemplatingthe Lajeado Hydroelectric Power Plant.

In 1988, the State of Tocantins was finally created,which increased the desire for the implementation ofprojects for the development of the region. The locationof the capital of the State, Palmas, was chosen to be onthe margins of a hydro power plant reservoir, and thus,with the technical studies already concluded, Palmaswas designed considering the water elevations of thefuture Lajeado Reservoir.

The contract for the concession was signed inDecember 1997 between the ANEEL - National ElectricEnergy Agency - and the companies integrating theConsórcio Usina Lajeado, which in turn delegated toINVESTCO S.A. (composed by the companiesparticipating in the Consortium) the responsibility forconducting the job of implanting the enterprise.

In October 1998, the first phase of the Tocantins Riverdiversion was concluded. The filling of the reservoir wasbegun in September of 2001 and in the following monththe first License of Operation of the power plant wasissued, to operate at El. 199 m, together with thecommencement of the tests for the entry into operationof the first generator unit with an installed power of180.5 MW. The Luís Eduardo Magalhães HydroelectricPower Plant was officially inaugurated on October 5 of2001 and entered commercial operation in December ofthat same year.

In March of 2002 the name of the plant was formallyaltered from Usina do Lajeado to Usina Luís EduardoMagalhães, in honour of the deceased president of thechamber of deputies.

The Tocantins River basin, upstream of the townMiracema do Tocantins, is situated between parallels9º and 17º South latitude and between meridians46º and 50º of West longitude. It corresponds to a drainagearea of around 184,000 km2, which is equivalent to 24%of the hydrographical basin of the Tocantins River withclose to 770,000 km2. The Tocantins River develops fromSouth to North, being formed by the confluence of thedas Almas and Maranhão Rivers, whose sources arelocated in the Plateau of Goiás, at elevations exceeding1,000 m.

The flows of the Tocantins River present greatvariability. The greatest flood on record was 28,588 m3/sand the minimum flow during the dry season was263 m3/s. In general terms, the amplitude of the flowFigure 1 - Location map of the Luís Eduardo Magalhães HPP


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regime at Porto Nacional varies from minimums around450 m3/s up to maximums of around 10,000 m3/s.

1.2. Suppliers of Goods and ServicesFor the implantation of the Luís Eduardo Magalhães

HPP it was decided to constitute a team of its own toundertake the general coordination, approval of thedesigns and supervision of the quality control, staffed byprofessionals with great previous experience.

The principal contracts for the implantation of thepower plant were signed with the following companies:

• Engineering Services, with Themag Engenharia eGerenciamento Ltda., with the scope of preparing theBasic design of the undertaking and the Final design ofthe Civil Works, in addition to verifying theElectromechanical Final design.

• Execution of the Civil Works with RCC - ConsórcioConstrutor da UHE Lajeado, constituted by the followingcompanies:

- Construtora Andrade Gutierrez S.A.- Construtora Norberto Odebrecht S.A.,entrusted with, in addition to the civil works of the

power plant and step-up substation, the provision andinstallation of the electromechanical elements embeddedin the first stage concrete.

• Electromechanical Equipment with the CELAJ -Consórcio Eletromecânico Lajeado, constituted by thecompanies:

- Voith Siemens Hydro Power Generation Ltda.- Bardella S.A.,

entrusted with the task of preparing the electromechanicalfinal design and the provision, erection andcommissioning of all the equipment and systems for thepower plant and the step-up substation and theconnection to the Basic Brazilian Network. For theerection of all the equipment and electromechanicalsystems. The CELAJ subcontracted the followingcompanies:

- ENESA Engenharia S.A.- ENERCAMP Engenharia e Comércio Ltda.The contracts were signed taking as a reference the

basic design of the power plant and establishing criteriafor awarding proportional bonuses for any reductionsobtained from optimizations introduced into the finaldesigns. The contracts also established incentives forthe commitment of the companies with the objectives ofthe investors, implanting an integrated planning and thusfacilitating the management of the interfaces in the workof the three companies.

2. DESCRIPTION OF THE LUÍSEDUARDO MAGALHÃES HPP

2.1. General Layout of the Power PlantAt the end of the technical-economic feasibility studies

the proposed general arrangement is the one indicatedin Figure 2, contemplating the installation of 6 generatorunits of 170 MW each, and a total installed power of1020 MW, of which 850 MW was in a first stage, andwith the spilling structures located separately from thewater intake / powerhouse complex. The term consideredat that time for the implantation of the enterprise was56 months between the beginning of the mobilization,the execution of the civil works and the beginning ofgeneration.

At the beginning of the development of the basicdesign, INVESTCO S.A., already in the phase ofpreliminary consultations with some constructioncontractors and erectors, began to evaluate, together withthe Themag, the possibility of reducing the terms for theconstruction with the purpose of anticipating thegeneration in relation to the time defined in the feasibilitystudies and taking as a base the date of July 1 of 1998for commencing the mobilization for the execution of thecivil works.

Figure 2 - General Layout - Feasibility Study


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Considering these parameters and the same designcriteria defined in the feasibility studies, a new alternativewas developed in which the assembly of the water intake/ powerhouse complex was located immediately adjacentto the spillway structures, in a layout designated as'compact' (see Figure 3). The elevation of the restitutionby the tailrace channel was maintained, with theconstruction of a large tailrace channel that guaranteedenergy and installed power similar to those of the valuesalready defined.

The same cross-sections were maintained for theprincipal concrete and earthen structures, including thecofferdams for the river diversion, and lower constructiontimes were obtained due to the simpler constructionlogistics, with a gain of six months in relation to the initialterm from initiation to generation, although with anincrease of the quantities that raised the cost of theimplantation by approximately US$ 16.7 millions.

The six months of anticipation in the start ofgeneration, when analysed in the scenario of the alreadygranted concession and with the fixed term of 35 years,on one hand represented an additional energy benefitwhile on the other it led to an acceleration of theinvestments which had to be completed six monthsearlier.

Taking as a reference for updating the energy benefitsthe beginning of generation of the first unit six months inadvance; an interval of three months for the installationof the subsequent units; the rate of R$ 35.95/MWh, inDecember 1997 (1US$ = R$ 1.1143) and the 10%discount rate, the following values result:

• Present value of the energy gain (2.15x106 MWh):US$ 72.1 millions.• Present value of the additional financial charges,resulting from the anticipation of the investments:US$ 24.1 millions.• Difference in favour of the anticipated generationalternative: US$ 48.0 millions, reduced toUS$ 31.3 millions upon considering the greater cost ofthe implantation.

In view of these studies, it was decided to adopt thecompact layout solution for the detailing of the basicdesign. In the final evolution of the studies, already atthe beginning of the final design, and without prospectsof the possibility of differentiated remuneration for peakenergy, it was decided to adopt the definite implantationof only five generator units, but with features that raisedthe total installed power to 902.5 MW, i.e., 180.5 MWper generator unit.

2.2. General Description of the Power PlantThe general layout of the power plant is basically the

same as that of the basic design and is constituted bythe following works:• Earth dam in the right bank, of homogeneous cross-section, vertical filters and horizontal sand blankets withtransition to mixed sections together with the futureconcrete structures of the navigation locks and theconcrete dam in the river channel, with crests atEl. 216.00 m, with a maximum height of close to 30 mand development of 560 m along the crest.• Dam of roller compacted concrete (RCC), gravity type

Figure 3 - General Layout - Basic design


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with a length of 587 m and a maximum height of43 m, crowned at El. 215.00 m.• Spillway in reinforced concrete, with a Creager profile,designed for a ten thousand year flow of49.870 m3/s, comprising fourteen bays with 17.00 m width,fitted with radial gates.• Spillway - water intake connecting dam of gravity type,in concrete, with a length at the crest of 37.50 m.• Water Intake/Powerhouse complex in a monolithicstructure of reinforced concrete, composed of five blockswith a length of 28.50 m each, housing five turbine-generator units with a per unit power of 180.5 MW.• Erection bay 54.4 m in length, in reinforced concrete,located in the left bank contiguous with the powerhouse,permitting, on the floor of the first generator unit, thesimultaneous erection of up to two generator units.• Earth dam in the left bank, of mixed earth/rockfill cross-section until the fish ladder and in homogeneous cross-section similar to that of the right bank up to the abutment,with a total length of 310 m and 26 m in height.• Fish ladder situated in the left abutment, for transpositionof migratory fishes.

The power plant is connected to the North-SouthInterconnected System through a 500 kV transmissionline that links the 230/500 kV Transformer Substation

beside the power plant to a connection bay in Miracemade Tocantins Substation. The purpose of this TL is thetransmission of the total energy generated by the powerplant.

It is also planned to install navigation locks in thepower plant, since the Tocantins River is an integral partof the Tocantins-Araguaia water highway, which in futureis to be extended to the city of Paranã.

Photo 2 - Powerhouse - Internal View

Photo 1 - General View of the Dam


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3. GEOLOGY, GEOTECHNOLOGY ANDFOUNDATIONS

3.1. Regional GeologyIn the area of the reservoir and its surroundings, there

are innumerable lithostratigraphical units, represented byvery ancient rocks from archean ages to recentsediments. The principal lithostratigraphical units presentin the flooded area and its surroundings are:

3.1.1. Cenozoic EraCapping large areas of the basin, principally in the

valley of the Tocantins River and of its tributaries, thereare alluvial deposits, dating from the most recent untilthe most ancient fluvial terraces, as well as colluvialcovers and talus deposits below the slopes. The cenozoicdeposits are represented by unconsolidated sediments,constituted predominantly by sandy soils associated withgravels, silts and clays, in good part laterized or containinglateritic fragments or granules.

3.1.2. Paleozoic EraThe paleozoic era is represented in the region by

following lithostratigraphical units:• Piauí Formation (Carboniferous) - reddish arcosesandstones with large-size crossed stratification• Longá Formation (Devonian) - shales with intercalationsof siltstones, well stratified, with levels of brownish yellowsandstones• Pimenteiras Formation (Devonian) - fine to coarsesandstones, siltstones and claystones, variegated.• Serra Grande Formation (Silurian - Devonian) - coarsesandstones, with levels of conglomerates, siltstones andgreyish claystones.

3.1.3. Proterozoic EraThe proterozoic era is represented by the following

units:• Estrondo Group (Middle Proterozoic) - quartzites withconglomeratic levels, mica-schists and amphibolites.• Natividade Group (Middle Proterozoic) -metaconglomerates, quartzites, phyllites and dolomites.• Lajeado Suite (Lower Proterozoic) - porphyroid granites

3.1.4. Archean EraIs represented by the following units: :

• Matança Suite (Lajeado Granite) - granitic rocks, coarsetexture, ash-green and roseate.• Morro de Aquiles Formation - mica-schists withintercalations of milonithic quartzites and schists.• Porto Nacional Complex - mafic and metabasicgranulites, milonitized enderbites and anortosite.

3.2. Local GeologyThe principal geological features present at the dam

site can be characterized as follows:

3.2.1. AlluviumsFrom the river banks in the direction of the abutments

there are extensive fluvial plateaux, represented by recentalluviums and more ancient terraces, the latter almostrestricted to the right bank. In the right bank there aremore recent alluviums, close to the cliff of the river bank,constituted by sandy silt, with little clay, cream and yellowcoloured. In the direction of the abutment there occursan alluvial terrace constituted by fine to coarse gravels ina matrix of clayey-siltose sand, micaceous, variegated.The thickness of the alluvial layer in the right bank variesfrom 1 to 6 m, resting upon altered granite soil and uponsandstone soil, it being absent at the end of the abutment.Water infiltration tests in the alluviums indicate generallylow permeabilities with a mean of around 1x10-4 cm/s.Tests of the resistance to penetration index indicate SPTvalues almost always superior to 10 blows.

In the left bank the alluvial layer possesses athickness of from 5 to 12 m, being constituted by finesilty-clayey sand, micaceous, yellowish, greyish andvariegated. In this bank the alluviums are seated directlyupon the sound granite, or in relatively thin layers of alteredsoil and granite saprolite. Close to the abutment thealluvium underlies a deposit of colluvium. .

Water infiltration tests in the alluviums of the left bankindicate very variable permeability values, ranging fromthe total pump flow (K>10-2 cm/s) to no flow at all, with amean of 5x10-5 cm/s. The resistance to penetrationindexes are also highly variable, with an average of8 blows, with several values below 4 blows, up to a depthof close to 5 m.

3.2.2. ColluviumsIn the area of the dam the colluvial deposits only occur

at the end of the abutments, with a maximum thicknessof around 1 m in the right bank and up to 10 m below theslope of the left bank. The colluvium is constituted byfine to coarse clayey sand, reddish brown, with lateriticgranules and fragments of quartz. In the right bank thepercussion soundings indicate high SPT values, with theaverage exceeding 10 blows. Water infiltration testsprovide permeability values below 1x10-5 cm/s, with totalflow from the pump occurring in two of the tests. In theleft bank the penetration resistance tests indicated thepresence of some layers of very spongy soil, with SPT =1 blow, and an average of around 5 blows.

The permeabilities are variable, in some cases withtotal pump flow and a mean of around 5x10-5 cm/s.

3.2.3. Sandstone from the Serra Grande FormationIn the axis of the dam, the occurrence of sandstone

was only verified in a fairly restricted area close to theright abutment, with a maximum thickness of around5 m.


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3.2.4. Matança Suite (Lajeado Granite)The most important lithology in the area of the dam is

represented by coarse granitoids pertaining to theMatança Suite, of the Archean era. This lithology wasdenominated Lajeado Granite, preserving thenomenclature proposed by Barbosa et al. (1966). TheLajeado Granite presents a coarse texture, showing wellformed crystals of feldspar, up to 3 cm in length, in analso coarse matrix of quartz, feldspar, pyroxene/amphibolite, biotite and chlorite. The grains presentgreyish, whitish, roseate and greenish colours.

There are dikes and veins of aplites, which intrudeinto the granites, of thicknesses in centimetres or inmetres. The aplites are fine grained, with light grey androseate colours, preferentially oriented between N-80ºand N-115º, with dips from the vertical to 40º toward NE.The aplite dikes form crossings in the riverbed, beingalmost always fused with the encasing granite, withoutconstituting discontinuities. The granites are alsoassociated with veins and dikes of pegmatite, withthicknesses up to several metres, constituted by quartzand feldspar, with crystals measuring centimetres, beigeand roseate. They are preferentially oriented in the N-15ºto N-80º strikes, with dips of 40º to the NE reaching thevertical, sometimes side-by-side with the aplites.

Along the axis, the Lajeado Granite constitutes theentire riverbed, in which it was possible to observeinnumerable outcroppings during the low water periods,with sporadic loose blocks upon the surface. In themargins the granites were capped with alluviums and toa small extent by colluviums and a restricted layer ofsandstone in the right abutment.

In the area of the dam there are various fault systems,some of a regional character, with a general North-Southstrike and vertical dip, along which, in a general manner,the valley of the Tocantins River is embedded. The mostdistinguished structural feature of the area is constitutedby faults that delimit the "Graben" of the Lajeado, whereslips of around 250 m are estimated, causing the loweringof the sandstones of the top of the Serra do Lajeadodown to the level of the Tocantins River. In theoutcroppings of the river bed the occurrence was verifiedof three systems of well defined alignments, constitutedby microfaults and extensive fractures, which must bereflections of the principal faults. These systems,designated F1, F2 and F3, develop approximately in theN-50 to 55º, E-W and N-160º to 170º strikes, with sub-vertical dips, sometimes constituting fault-boxes of upto 5 m in thickness, where the rock appears somewhataltered, very fractured, with the fractures generally sealedby clayey and/or granular material. The systems F1 andF2 are more extensive and of more unfavourablegeomechanical characteristics, although with fewoccurrences in the area of the jobsite. The F3 system ismore frequent, although the alignments are little extendedand the fractures present rock to rock contact.

In general the granitic bedrock presents fairly high

geomechanical characteristics, without totally preventingthe occurrence of some weak zones represented by thefaults. In addition to the faults, there are some fracturesystems, in general at the rock to rock contact or sealedby rigid material, sometimes with striation and with afilm of oxidation, oriented from the sub-horizontal to thesub-vertical.

Outside of the fault zones, the rotary drill soundingsindicate a sound rocky mass, little fractured, havingalmost always obtained a 100% degree of recovery ofthe core samples and a high RQD index. Tests of waterloss under pressure indicate a rock mass of low hydraulicconductivity, outside of the fault zones where some highwater losses occur, and even cases of total flow of thepump with a capacity of 140 l/min.

The altered soils and granite saprolites are littleextended on the left bank, where the alluviums rest almostdirectly upon the sound rock. In the right bank thethicknesses of the granite soil are more significant,reaching close to 15 m at the end of the abutment. Thegranite soils in general present high indexes of resistanceto penetration, with an SPT average greater than 15 blows.The water infiltration tests from the soundings indicategenerally low permeability values, with the average around1x10-4 cm/s.

The consolidation tests carried out in the laboratoryon undisturbed samples of granite soil determinedpermeability coefficients of 4 x 10-4 to 5 x 10-6 cm/s, whensubjected to loads of 100 to 400 kPa. The compressionindex obtained was 0.39. Slow triaxial tests on alteredgranite soil samples from the foundation in the left bank,indicated an angle of rest of 28º and 56 kPa for thecohesion intercept.

3.3. Investigations Carried OutFor the preparation of the basic design, including the

data surveyed in the feasibility studies phase, thefollowing geological-geotechnical investigations weredeveloped:• Geological mapping, to the scale of 1:5,000, at the siteof the selected axis;• Geological survey along the Tocantins River and itsbanks, up to 20 km upstream and 20 km downstream ofthe axis, for mapping the sand and gravel deposits, withcollection of samples for laboratory tests and estimatesof volumes.• Research and tests for defining the foundations and• Research and tests for selecting the natural constructionmaterials.

Table 1 indicates the investigations and testsexecuted:


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3.4. Characteristics of the Foundation Rocks andConstruction Materials

The investigations and tests executed for researchingthe foundations indicated fairly favourable geological andgeotechnical characteristics for the support of thestructures, which was proven during the construction.The principal geological and geotechnical conditioningfactors of the foundations can be summarized as follows:

3.4.1. Foundations of the Earth WorksIn the right bank the dam is constituted by a

homogeneous cross-section of compacted soil. Thealluviums, colluviums and sandstones that cap the alteredgranite soils, present layers with gravels of highpermeability in some stretches and thus condition theexecution of a sealing trench with a penetration of closeto 1 m in granite soil. The covering soils and the alteredgranite soils present a medium to high compactness,with an angle of rest of around 28º. The stretch of theenfolding connection with the concrete structure restedupon the granite bedrock, with the total removal of theoverburden soils and is constituted by a mixed sectionof earth/rockfill.

Table 1 - Investigations and Tests Carried Out

In the left bank the earthworks rested upon alluviumsand colluviums, with the principal conditioning factor ofthese materials being the high compressibility, withpredominance of low SPT values until close to 4 m indepth. Since the high compressibility was demonstratedby oedometric tests and having, furthermore, observedthe collapse of test samples in the flooding, the alluvialand colluvial soils were partially removed, and a sealingtrench was implanted until penetrating 1 m into thealtered/saprolite granite soil or until reaching the top ofthe sound rock, where the alluvium rests directly uponthe bedrock. From the sealing trench, exploratoryinjections of cement grout were practiced to prevent therisks of transportation of soil particles through fracturesin the bedrock. From the water intake to the fish ladderthe dam was constructed with a mixed section of earth/rockfill and from the fish ladder to the abutment the cross-section is homogeneous compacted soil.

3.4.2. Foundations for the Concrete StructuresAll the concrete structures rest upon granite bedrock

of high geomechanical characteristics, in which theprincipal conditioning factors were represented by some


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faults, predominantly sub-vertical. Due to the sub-verticalcharacter of the principal weak zones, no sliding problemscaused by the presence of stresses were encounteredin the foundations. The foundation treatments wereconventional consisting of the removal of the most alteredand fractured materials, and execution of grout anddrainage curtains.

3.4.3. Natural Construction MaterialsThe investigations in the area of the dam and of its

surroundings indicated the great potential of the naturalconstruction materials, with adequate geotechnicalcharacteristics and short distances from the job. Theearthen materials are abundant in both margins, withdistances of less than 2.5 km from the site of theirapplication, as well as the materials from the obligatoryexcavations.

The borrow areas in the right bank showed theoccurrence of a single superficial layer of transportedsoil, with thickness less than 2 m, covering the originalgranite soils represented by residual soils of reducedthicknesses and of alteration with more significantthicknesses.

The residual and altered soils present homogeneouscharacteristics, principally for particles retained on the200 (0,074 mm) screen. In the smaller diameters theresidual soils present a major content of clay and less of

silt than the less mature soils (saprolitical). These soilspresent a grain size distribution varying from silty-clayeysand to sandy-clayey silt. The altered soils incorporatemicaceous granules and fragments of quartz and feldsparwhich become more present as the depth increases.

Samples moulded in the laboratory under conditionsof embankment compaction (optimum moisture contentand 98% compaction) and subjected to tests revealedpermeability coefficients varying from 10-5 to 10-6 cm/s.Triaxial compression tests determined, in effective terms,angles of rest of 31º and 32 kPa of cohesion intercept.

Figure 4 presents a synthesis of the geotechnicalcharacteristics of the materials from the right bank,determined in the laboratory.

In the left bank, the areas investigated wereconstituted predominantly by alluvial materials and areascomposed of colluviums and granite decomposition soils,with small occurrences of siltites/claystones from thePimenteiras Formation. The alluviums are predominantlyconstituted by fine clayey sand, with minor occurrencesof clayey-sandy silts. The colluviums are fundamentallycomposed of fine sand and coarse clay. Coefficients ofpermeability of around 3x10-6 cm/s were determined.Triaxial compression tests executed in the laboratorypresented, in effective terms, angles of repose of31º and cohesion of 24 kPa.

Figure 4 - Geotechnical Characteristics of the Materials from the Right Bank


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Colluvial soils of variable thickness cover the residualor altered granite soils, observing in a few places, alteredsiltite/claystones from the Pimenteiras Formation.

The constitution of the colluvial soils presents fractionsof clay and silt that are very similar to the samplescollected in the right bank, although with small differencesin the percentages of fine and medium sand. Thedecomposed granite soils present characteristics thatare analogous to those observed in the right bank. Theoccurrences of altered soils of claystones and siltitespreserve the placoidal aspect of the original rock, resultingin clayey siltites when tested in the laboratory. Thelaboratory tests on samples of colluvial soil gavecoefficients of permeability of around 2x10-5 cm/s andangle of repose 28º and cohesion intercept of 4.7 kPa.Samples of altered granite soil presented meanpermeabilities of around 10-5 cm/s and, respectively,32 kPa and 31º for cohesion and angle of repose.Triaxialtests on samples of altered siltite soil determinedcohesion of 19 kPa and angle of repose of 27º.

Figure 5 presents a synthesis of the geotechnicalcharacteristics of the materials from the left bankdetermined in the laboratory.

Rock for rockfill, rip-rap, transitions and aggregate forconcrete were obtained from the granites, whose volumesof obligatory excavation surpassed by far the needs ofthe job. The excavated granites present high strength.Accelerated cycling tests (wetting and drying) indicatedthat the granites are very little susceptible to

disaggregation. Core samples exposed to environmentalconditions for more than 2 years remained practicallyunaltered.

Petrographic thin sections and six samples of graniteindicated weak undulating extinction, with a mean anglelower than 25º. The granite possesses a density ofaround 2.7 and absorption of 0.13%. The greater part ofthe sand utilized for the job is artificial sand since thenatural beds are distant from the site of the power plant.

3.5. Foundation Treatments

3.5.1. Earthen and Rockfill DamsAs a deep treatment, an inclined cement grout curtain

was executed, starting from the base of the trench, witha depth in rock of 15 m.

3.5.2. Concrete StructuresSince, in general, the foundation rock surface was

already sound and little fractured in the region of the RCCdam in the river bed, the concrete was poured after theroutine execution of the preparation and of the surfacetreatment. In only a few localized zones was necessaryto somewhat deepen the excavations due to unfavourablegeomechanical characteristics.

For the remaining structures, such as thepowerhouse, erection bay, spillway and connecting wall,the excavations were made down to the elevationsindicated in the project drawings.

Figure 5 - Geotechnical Characteristics of the Materials from the Left Bank


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The deep treatment consisted of inclined grout curtainand drainage holes, executed from the galleries thatsurround the structures. The curtain was executed withdepths that varied between 20 and 25 m in the spillway,20 and 36 m in the powerhouse and 23 m in the erectionbay. The drains were executed with 3 m spacing betweenthem and similar depths to those of the grout holes.

The foundation treatment of the slab of the dissipationpool consisted of a mesh of anchors of 2.4 x 2.2 m, witha depth of 5 m, and of drains. The drainage was realizedby seating half-round channels directly on the bedrock,in modules of 7 x 5 m, complemented by inclineddrainage holes 8 m in depth, executed at the intersectionof the half-round channels.

4. HYDROLOGY, HYDRAULICS ANDENERGY STUDIES

4.1. ClimateThe climate of the project region can be characterized

as tropical continental, alternating from humid to dry.The annual temperatures in the region tend to diminish

with an increase in latitude, varying from 26º in the Northto 21ºC at the limits with the State of Goiás. In the areaof the power plant, the maximum mean temperature variesbetween 30ºC to 33ºC, while the minimum mean isaround 17ºC to 21ºC. These thermal minimums areoriginated by the cold fronts coming from the polar region.The continental location of the area makes the night-time temperatures pleasant in comparison with the diurnaltemperatures.

The sunshine of the region varies around 2,400 hours/year corresponding to a daily mean of 6.6 hours ofsunshine. The maximum sunshine period occurs in Julywith mean of 10.3 hours per day and the minimum with4.8 hours/day occurs in the month of January, which isthe period of intense rainfall.

In the period from January to March, the relativehumidity of the air reaches mean values of around 83%in the North part of the basin and 77% in the Southernpart. During the drought period from June to Septemberthese values are 55% and 45%, respectively.

The rainy period is well defined, going from Octoberto March while the driest period runs from June to August.The annual mean rainfall varies from 1500 mm and2000 mm, concentrating close to 85% of the total annualprecipitation in the rainy period.

4.2. HydrologyThe fluvial regime of the basin accompanies, in general

lines, the dominant pluviometric regime in the region,presenting a period of high flows between November andApril and a drought period between May and October.A general appreciation of the surface hydric potential,based on the mean flows observed in the principal stationsof the regions, warrants the conclusion that:

• In the High Tocantins basin, upstream of the mouth ofthe Paranã River, the specific flows gradually decreasefrom upstream to downstream. The mean specific flowsevaluated at the stations of Uruanã, Porto Uruaçu andCana Brava I were respectively 19.91, 18.13 and17.64 l/s/km2. In seasonal terms, the mean values of themean monthly flows vary from 30 to 40 l/s/km2, in thethree months from January to March, and to valuesbetween 5 and 10 l/s/km2, in the three months from Julyto October.• Along the Paranã River in the Southeast portion of theTocantins basin, the specific flows are relatively reduced.In this case, the mean flows at the stations of PonteParanã and Paranã were only 11.80 and12.27 l/s/km2, respectively. In seasonal terms, the meansof the monthly mean flows vary from 20 to 30 l/s/km2, inthe three months from January to March, to values slightlybelow the 5 l/s/km2, in the three months from July toSeptember.• In the Middle Tocantins basin, upstream of the Lajeadopower plant site, in the area represented by the FazendaLobeira Station on Manual Alves River, the mean flowsattain intermediate values, 15.97 l/s/km2, although witha strong seasonality between years. In this case theaverages of the mean monthly flows vary from 30 to40 l/s/km2 in the three months of January - March, withvalues of around 3 l/s/km2 in the three months from Julyto September.• The integration of these three portions of the basin iswell characterized by the Porto Nacional station in theTocantins River, which has been in operation since 1949.The mean flow at the station is 15.08 l/s/km2, with theaverages of the monthly means of the flows varyingbetween 25 to 35 l/s/km2, in the three months of Januaryto March and values of around 5 l/s/km2 in the four monthsof July to October.

The greatest flood flow recorded in the Tocantins River,at Porto Nacional, occurred on February 24, 1980, withan estimated discharge of 28,558 m3/s. At the same site,the lowest flow of the historical period occurred on October19, 1954, with a flow of 263 m3/s. In normal years, theamplitude of the flow regime at Porto Nacional goes fromminimums around 450 m3/s to maximums around10,000 m3/s. With the impounding of the Serra da Mesareservoir in the middle of the 1980s decade, there occurredan appreciable regulation in this flow regime, with theelevation of the minimums to values frequently surpassing800 m3/s.

For the definition of the monthly mean design flows,covering the period from 1931 to 1994, an analysis wasmade of two long-period series available from thefluviometric station of Porto Nacional, situated upstreamof Lajeado and the only one with a long series of data:• Series of monthly mean flows provided by the DNAEE,covering the period from 1949 to 1994.• Series of monthly mean flows covering the period 1931to 1984, defined through the deterministic model of


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hydrological simulation called LIMAY. This series wasgenerated during the development of the Inventory Studiesfor the Middle Tocantins: "Estudos de Geração de VazõesMédias Mensais na Bacia do Alto e Médio Tocantins" -Eletronorte - TOC-02-698-RE-02/1987.

From the comparative analysis of the two series(common period from 1949 to 1984), it was observedthat the years 1959, 1960, 1961, 1966 and 1981 werethe only ones to present discrepancies in the wet period,with the model series being systematically drier thanthe DNAEE series, probably due to alterations in thevalues of the water levels observed.

For greater data reliability and consistency, it wasdecided to utilize, in the period from January/1931 toDecember/1984 the series of mean monthly flows of theLIMAY, with the period of January/1985 to December/1994 complemented with the DNAEE series. The gapsexisting in the years of 1989, 1990, 1992, 1993 and 1994,were filled-in by correlations of mean monthly flows withthe data from the Peixe and Tupiratins stations.

With the series of mean monthly flows defined for thePorto Nacional station covering the period 1931 to 1994,the flows were transferred to the power plant site, utilizingthe coefficient obtained from the ratio between drainageareas.

To obtain the conditions for the dimensioning of thewater discharge structures of the diversion works and todetermine the maximum natural water levels associatedwith the periods of recurrence at the site of the powerplant, a statistical study of the maximum flows wasundertaken. The research on the maximum flows wasdeveloped based on a series mean daily flows at thePorto Nacional fluviometric station (1949-1994). It shouldbe pointed out that the maximum of the 1990/1991 floodwas not used due to the total absence of data on the1991 flood. A statistical study was made initially of theannual series of daily maximums at Porto Nacional,adjusting the distributions of Log-Normal, Gumbel-Chow,Exponential, Pearson III and Log- Pearson III.

The distribution with the best adjustment was theGumbel-Chow, which was utilized to define flows fordifferent periods of recurrence at Porto Nacional. Totransfer the flood flows from the Porto Nacional stationto the power plant site, a curve of regionalization wasused between the flood flow "versus" drainage area fordifferent stations in the basin, defining a coefficient forthe increase of K= 1.02447.

By means of these studies it was possible to definethe values of the flood flows for the project:

Period of Recurrence Flood FlowTR (years) Q (m3/s)

25 23,01950 26,161

1,000 39,58010,000 49,870

With a view to confirming the values thus defined,studies were also developed to determine the Probable

Maximum Precipitation (PMP) and of the ProbableMaximum Flood (PMF), corresponding to the TocantinsRiver basin down to the Luís Eduardo Magalhães HPP,with a drainage area of around 184,000 km2, consideringthe basin both under natural conditions and underconditions of a developed river with the incorporation ofthe planned upstream developments. The resultsobtained confirmed the above values, since the differencesobtained were of the order of 1%.

Wind studies were also developed in order to definethe freeboard values, resulting in 3.0 m for the concretestructures and in 4.0 m for the earth works and rockfill.For the backwater studies in the reservoir, 15 sectionswere analyzed, embracing a 200 km stretch. The waterline profiles were obtained by mathematical simulation,through a model of the "Standard Step Method", withManning coefficients adjusted for each of the marginsand for the river bed, in the diverse instantaneous profilesmeasured in the limnimetric stations existing in thestretch. Once the model was calibrated for the profilesobserved, the verifications were made of the behaviour ofthe river under natural conditions and with the reservoir,for flows corresponding to the mean annual, five hundredyear, one thousand year and ten thousand year floods.

The studies on silting of the reservoir and the definitionof the useful life of the enterprise were carried out asrecommended by Newton de O. Carvalho, obtaining auseful life of approximately 100 years, without consideringthe influence of the Serra da Mesa reservoir, which issubstantially reducing the transportation of sediments inthe high and middle reaches of the Tocantins River.

4.3. Hydraulics StudiesThe hydraulic conception of the power plant was based

on the tests with a three-dimensional small scale model(scale 1:120) carried out by Fundação Centro Tecnológicode Hidráulica - FCTH of the University of São Paulo -USP.

The following tests were developed with the aim ofsubsidizing the final design of the power plant:

1. Tests on the small scale model relative to the1st phase of the river diversion, comprising:• Placement of the pre-cofferdam - 1,700 m3/s• Water-proofing of the pre-cofferdam: 1,700 m3/s• Stability of the cofferdam 23,019 and 26,160 m3/s• Placement of the auxiliary cofferdam in the right bank:1,700 and 2,500 m3/s• Characterization of the discharge for the 1st phase ofthe river diversion: 2,500, 5,000, 10,000, 15,000, 20,000,23,019 and 26,160 m3/s• Water-proofing of the auxiliary cofferdam in the rightbank: 1,700 and 2,500 m3/s

2. Tests relative to the 2nd phase of the river diversion,aiming to define the number of lowered bays in thespillway, as well as the elevation of the lowering. Thelowered bays were initially executed with the sill at theelevation 177.50 m , being subsequently raised to the


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elevations 178.50 m and 179.50 m. In order to simulatethe different number of lowered bays, flat wooden gateswere prepared which, inserted into the guides of thestoplogs, permitted the closure of 1 or 2 lowered bayson the left side of the spillway.

3. Tests relative to the 2nd phase of the river diversionwere conducted with the aim of characterizing thedischarge during the works of raising the lowered baysof the spillway, as well as to define the sequence of theraising operation. To carry out the campaign of the tests,a model was implanted with a configuration of the generallayout of the structures, comprising the spillway with8 complete bays and 6 bays lowered to theEl. 177.50 m, dissipation pool at the El. 173.00 m andwith the length reduced by 20 m in relation to the originaldesign, the RCC dam complete and the with the remnantsof the upstream and downstream stretches of the1st phase cofferdam.

4. Tests relative to the general layout of the structures,conducted with the aim of evaluating the oscillationcharacteristics of the water level downstream of thestructures. These tests employed the AQUI System dataacquisition with the assistance of two Capacitive Points.

For the joint operation of the spillway and of thepowerhouse the test involved a total flow of 23,068 m3/s,of which 19,768 m3/s was through the spillway and3,300 m3/s through the powerhouse; for this total flowthe downstream water level, at the axis of the job is equalto 192.30 m; a value that corresponds to the maximumdownstream water level for the operation of thepowerhouse. Another test comprised the maximum flowwith the isolated operation of the spillway - 50,925 m3/s.The layout of the model was the same as in the previoustest, with the 14 openings complete. The powerhousewas implanted with 5 units and the headrace and tailracechannels were built in accordance with the final design.

The tests consisted in measuring the oscillations ofthe water levels downstream of the earth dam of the rightbank, in its enfolding connection with the RCC dam andthe tailrace channel, downstream of the unit 1 draft tubeof the powerhouse. These tests were repeated for thesmaller flows that are more frequent in the Tocantins River.

5. The tests relative to the operation of the powerhouseaimed at evaluating the formation of vortexes at the waterintakes and to propose measures to eliminate them.

The test was carried out on the complete model andcomprised 7 stages:• 5 units in operation• 4 units in operation• 3 units in operation• 2 units in operation• 1 unit in operation• Joint operation of Spillway/Powerhouse• Operation of the Powerhouse with upstream water levelat El. 206.00 m,

The tests of the stages 1 to 6 were carried out withthe reservoir water levels varying between El. 211.00 m

(minimum exceptional water level) and El. 212.30 m(maximum normal water level). The flow from each unitfor all the tests was equal to 660 m3/s. For evaluating theintensity of the vortexes, the classification proposed byDurgin & Hecker (1978) was adopted. The isolatedoperation tests of the powerhouse showed a more intensevorticity in the unit 5, right opening. For the remainingunits the vorticity is less intense, not demanding specialmeasures. An anti-vortex device was designed for theunit 5, right opening.

6. Tests relative to the 2nd phase of the river diversionwere conducted with the aim of characterizing thedischarge, providing elements for defining the bestalternative for closing the river and to indicate the grainsize of the materials to be used in the placement of thepre-cofferdams. The tests on the 1st phase of the riverdiversion aimed at verifying the stability and the velocitymeasurements, waves and water levels along thecofferdam of the tailrace channel. The tests on the riverclosure were made by placing the rows of the pre-cofferdams, always in the direction from the left bank tothe right bank and for various alternatives lengths of theupstream and downstream first stage ridges in the rightbank. The test flows for the closure were of 2,000 and of4,000 m3/s. The test for the 4,000 m3/s flow wasconducted in an abbreviated manner (withoutmeasurements of velocity and water level), without anylarge loss of material being observed for the condition of7 openings lowered and which could not be closed withB8 type crushed rock. The test for verifying the stabilityof the tailrace channel cofferdam was run with a flow of26,160 m3/s.

7. Tests were run for obtaining the rating curve of thespillway, for total and partial openings of the gates. Thetest campaign consisted in measuring the water levelsupstream for diverse conditions of operation. The curvewas further checked by tests on a two-dimensional modelof the spillway.

8. Tests with the aim of establishing the operationalrules for the spillway gates. Tests were carried out forthe following conditions:• Normal operation that consists of the imposition of equalopenings for all of the 14 spans, or differentiated only bythe "operational pitch" (1 m) or the "final pitch" (of theopening of 12.5 m until the fully open position).Asymmetries of the "pitch" were verified, i.e.,combinations of openings with spans of 12.5 m and total,in addition to the manoeuvres for discharging reducedflows, with the opening of particular spans with 1 m andthe rest closed.• Unusual operations consisting of tests with manoeuvresresulting from the impossibility of opening1 or 2 spans (spans under maintenance) and gate testmanoeuvres, which involve the isolated opening of onlyone gate, starting from the closed condition and continuinguntil fully open. The procedure employed in the testsconsisted in stabilizing the discharge from the model for


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a particular manoeuvre and observing the dischargedownstream, verifying the occurrence of recirculation, flowseparation, turbulence and dragging of blocks of rockfrom downstream into the interior of the dissipation pool,as well as conditions of energy dissipation and dischargeof the flow downstream of the basin. According to thebehaviour, the manoeuvres were classified as"satisfactory", "acceptable", "emergency" or "forbidden".

4.4. Energy StudiesIn accordance with the energy studies, the principal

characteristics of the development were:• Maximum normal water level with run-of-the-riveroperation 212.00 m• Minimum installed power of 850 MW with 5 generatorunits• Firm energy, after the complete motorization4,468,476 MWh/year until the entry into operation of theTupiratins HPP when the assured energy becomes3,708,198 MWh/year.• Firm power, after the complete motorization701.50 MW

However, the owner decided not to limit the power ofthe acquired turbines, whose rated power is 183.48 MW,by the capacity of the generators. Therefore, as thecapacity of each generator is 190 MVA, equivalent to180.5 MW, the final installed power of the plant is902.5 MW.

The final evaluation of the energy parameters wasmade from simulations, at the monthly level, of areference system that encompasses an assemblage ofthe power plants in existence, or under study or beingplanned, that aims to represent the national generatorpark with a horizon of close to 10 years. This referencesystem includes the principal power plants of theinterconnected systems of the South/South-East/Centre-West and North/Northeast. The simulations were runprincipally during the critical period of the interconnectedsystems (June/1949 to November/1956) for someoperational scenarios of the Luís Eduardo MagalhãesHPP. The simulations were run imposing an "objectivemarket" for the system that resulted in zero failures,corresponding to the critical load of the simulated system.These simulations formed the basis for calculating thefirm energy values.

Firm energy values were calculated for the followingsituations of the development of the Tocantins Rivercascade:• First stage - the entire reference system and in theTocantins basin only the developments of Serra da Mesa,Cana Brava, Lajeado and Tucuruí I.• Second stage - the entire reference system and all thepower plants of the Tocantins, except the Tupiratinspower plant.• Final stage - the entire reference system and all thepower plants of the Tocantins including the TupiratinsHPP.

The data employed for the simulations was:• Turbine- Rated power per unit 183,483 kW- Rated net head 34 m- Net reference head 29 m- Efficiency 94.53%- Number of units 5• Generator- Rated power 190,000 kVA (180.5 MW)- Efficiency 98.69%• Loss of head in the hydraulic circuit 1.7%• Rate of unavailability/reserve 13%• Rating curve at the outlet of the draft tube. Thescenario of the final stage with the TupiratinsHPP included the backwater effect caused by Tupiratinsdam.• Series of monthly mean natural flows - available in theSIPOT/2000.• Period of the simulation 1931 to 1996

5. DESCRIPTION OF THE PRINCIPALSTRUCTURES

5.1. River DiversionIn accordance with Figure 6, the diversion of the

Tocantins River for the Lajeado plant was effected in twodistinct phases, of which the first was divided into twostages. In the first stage of the first phase, the river wasmaintained partially in its natural riverbed, and the areaof the principal concrete structures remained protectedby compacted soil cofferdams, protected by rockfillwhere necessary. Accompanying the descent of thenatural water levels, in the area outside the cofferdam,part of the tailrace channel was excavated and, duringthe following dry season, the second stage of the firstphase was implanted, and the excavations of the tailracechannel concluded.

The second phase was characterized by the riverdiversion through the spillway structure, in 6 bays withthe sills lowered, with the construction area of the damin the river bed protected by cofferdams constituted byplaced rockfill, and with external sealing. Thedetermination of the number and the elevation of theoverflow of the lowered sills was made considering thatthe placement of the second phase cofferdams, upstreamand downstream, was simultaneous, guaranteeing theparticipation of the difference in levels on both work fronts,so that the maximum difference in levels in the breaches,was less than 3.00 m, admitting, conservatively, aparticipation in the falls of a maximum of 20% of thedifference in levels of the least stressed breach. Withthe closure of the gates of the openings by lowered sills,in a planned and consistent manner, with the natural flowsof the river and the raising of the dam in the river bed, thesecond phase culminated with the beginning of reservoirimpoundment.


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Figure 6 - River Diversion Phases

5.2. DamThe dam is constituted by five different dam stretches:

• In the right bank an earthfill dam was built, ofhomogeneous section, and with vertical filters andhorizontal drainage filters of sand with transition to mixedsections at the future concrete structures of the locks,and at concrete dam of the river channel. The dam hasits crest at El. 216.00 m, with a maximum height of closeto 30. 00 m and a length along the crest of 560.00 m.• The dam in the principal channel of the Tocantins Riveris in roller compacted concrete (RCC), of gravity type,587.00 m in length, maximum height of 43.00 m, andwith its crest at El. 215.00 m.• Spillway, connection dam and water intake in typicalgravity section, in conventional concrete with a lengthalong its crest of 37.50 m.• A dam of mixed earth/rockfill section was built in the leftbank up to the fish ladder and an earth dam ofhomogeneous section, similar to that of the right bank,up to the abutment. The total length of this stretch of the

left bank dam is 310.00 m with a maximum height of26.00 m.

The dam is complemented by a fish ladder for thetransposition of migratory fishes. Its attraction point islocated in the most downstream stretch of the tailracechannel and facilitates the transposition of migratoryfishes to water levels of the reservoir varying between theelevations 211.50 m and 212.30 m and the minimumdownstream water level of El. 176.00 m. Its mean declivityis 5%, and it contains four resting tanks at intermediatelevels of around 8.00 m.

The fish ladder is depicted by Photo 3 and 4.

5.3. SpillwayThe spillway is constituted by 14 blocks with a total

length of 323.00 m. Its maximum capacity is49,870 m3/s. Its dimensions were exhaustively tested insmall scale model tests, as described under item 4.3.

Each one of the 14 blocks is equipped with a radialgate with a net width of 17.00 m and a height of 23.50 m,


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an oleo-dynamic centre for each two blocks and twoservomotors for the gate manoeuvres.

A stoplog gate composed of 10 elements can be usedfor closing a bay for any repairs to the gate or even thespilling profile.

The same rolling gantry crane as for the water intakeis used for moving and erecting the spillway equipment.

5.4. Water Intake - PowerhouseThe water intake - powerhouse complex is formed by

a monolithic structural system constituted by fiveindependent units with a width of 28.50 m and anupstream-downstream length of 85.50 m, separated fromeach other by expansion joints fitted with joint seals.

At the left abutment there is an erection bayconstituted by a 26.00 m block and by a 13.00 m blockfor unloading equipment.

The water intake of each unit is divided into threeparts, with free entrances 5.65 m in width and 27.00 m inheight provided with trash racks in nine removable panels.

The stoplog gates have a free span of 5.65 m and a freeheight of 16.82 m and can be installed immediately upstreamof the fixed wheel gate for draining the hydraulic circuit.

Photo 3 - Fish Ladder - General View

Photo 4 - Fish Ladder - Detail

The emergency fixed wheel gates have a free span of5.65 m and a free height of 15.50 m and are driven byservomotors with oleo-dynamic centres withswitchboards under local command. The rated flow of awater intake block is 660 m3/s.

Upon the crest of the water intake at El. 215.00 mthere is a rolling gantry crane with an electrical windlassfor operating the stoplog gates, the fixed wheel gatesand the servomotors. This gantry crane also attends thecrest of the spillway. A rack cleaning machine wasinstalled for cleaning the racks.

Immediately downstream of the emergency gate,between elevations 185.00 m and 215.00 m, gallerieswere installed for the equipment and mechanicalsystems, as well as pits for raising the cables andventilation ducts.

The mechanical gallery at El 185.00 m is served alongits entire length by a mono-rail equipped with an electricalwindlass of 50 kN capacity.

The powerhouse infrastructure extends from thefoundation of the draft tubes, at El. 142.00 m, to the floorof the generator hall at El. 185.00 m. This infrastructureis composed by the draft tube in concrete with the steellining of the vertical portion and of the stretch upstreamof the septum of the turbine pit, and the spiral casing inconcrete, serving as the support base for the stator andintermediate guide bearing of the generator unit.

The access to the turbine pit is obtained through agallery situated at El. 174.40 m and the access to thedraft tube is through the gallery at El. 157.00 m.

The powerhouse superstructure is of the shelteredtype, extending from the floor of the generator hall atEl. 185.00 m to the cover at El. 216.50 m and comprisesthe machinery hall and the electromechanical galleries.

The erection of the powerhouse equipment is executedby two principal rolling bridge cranes of 2700/300 kN,supported by concrete beams.

Downstream of the powerhouse proper andinterconnected to it, are situated the electrical galleriesat the elevations 180,00 m, 185,00 m, 192,00 m, themechanical gallery at El. 174.40 m and the ventilationgallery at El. 198.00 m.

Upon the upper external downstream platform, locatedat El. 205.40 m, were installed 5 step-up transformers,as well as a roadway for vehicle circulation.

The system for closing the draft tubes was installeddownstream of the electrical galleries. This closure canbe made by 4 stoplog gates for the draft tubes of2 generator units of the powerhouse. During theconstruction phase, the remaining draft tubes wereprotected by concrete arches. A rolling gantry crane wasinstalled on the platform to handle the manoeuvres of thestoplogs.

The generator units are composed by 5 Kaplan-typeturbines with a rated power of 180.5 MW, at the netreference head of 29 m and 5 synchronous, three-phase,generators of 190 MVA, 100 rpm, 13,8 kV, 60 Hz, with a


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power factor of 0,95.The energy is conducted to the step-up transformers

through 5 sets of 13.8 kV, shielded three-phase isolatedbus-bars, with natural cooling.

Figure 7 presents a typical section of the Water Intake- Powerhouse complex.

The principal mechanical and electrical auxiliarysystems are:• Water Cooling and Service System• Draft Tube Draining and Filling System• Drainage System of the Powerhouse• Hydraulic Measurement System• Compressed Air Service System• Ventilation and Air Conditioning System• Potable Water System• Sewage Drainage System• Fire Protection System of Generators and Transformers• General Fire Protection System through PortableExtinguishers and Hydrants• Transformer Oil Drainage System• Lubricating and Insulating Oil Systems• Excitation and Voltage Regulator System• Command, Control and Supervision Systems• Electromechanical Workshop

Figure 7 - Water Intake - Powerhouse - Hydraulic Circuit

6. CONSTRUCTION

6.1. Jobsite Industrial YardThe jobsite industrial yard was implanted in the left

bank of the Tocantins River, downstream of the finalstretch of the powerhouse tailrace channel. As can beseen in Figure 8, the layout is fairly compact and in itsdownstream end were placed the lodgings, a commercialcentre, first aid station, dining halls and leisure areas.

6.2. Construction Planning - Construction ScheduleCommencing with the establishment of a basic

schedule and once it was associated with a list of basicdeadlines, all the contracted firms, by means of interactiveadjustments, committed themselves to observe thespecific schedules, which were compatible with eachother. Part of the basic deadlines was utilized to controlthe releases for the payment of the respective globalprices.

The strong coordination of INVESTCO S.A.,associated with well prepared contractual instrumentspermitted an optimal development of the actions directedtowards the materialization of the enterprise. Figure 9indicates the construction schedule, the principal goalsinitially established and the reality attained. In spite of


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having initially established a challenging schedule,providing for the beginning of operation in 43 months afterthe commencement of the civil works, the real termobtained was 41 months. This was an important advancein relation to the term of 56 months contemplated in theinitial phase of the basic design. The same Figureindicates the histogram of the concrete works. To obtainthese production figures, in addition to the intensive useof pre-assembling, the concrete:• Was poured in lifts 2.5 m in height and, in the waterintake pillars and spillway, the intensive use of slip-formspermitted the execution of continuous concrete poursup to 25 m in height.• It was refrigerated by the introduction of crushed ice inthe mix, permitting it being poured with a temperature of16ºC.

• It was dosed employing Portland cement withfly ash with the aim of reducing its reactivity, since theaggregates were potentially reactive with the cementalkalis.

Other highlights with reference to the executiveplanning:• Erection bay - simultaneous erection of 2 generatorrotors, permitting the conclusion of the generator unitswith a phase difference of 3 months.

• Powerhouse and water intake protected upstream anddownstream by temporary cofferdams.• Conclusion of the erection of the 2 first units before thereservoir filling in order to diminish the interval betweentheir initial generations.• Initial generation of the first unit with pre-filling of thereservoir before the final closure.

6,400 workers were mobilized in the industrial jobsiteduring the peak of the job.

6.3. Optimization of the Project and ConsequentCost Reduction

With the ample participation of all the contracted firms,INVESTCO S.A., promoted, in addition to the advancesalready attained since the feasibility studies, theintroduction of various improvements in the course of thefinal design, among which we should highlight:

• Concrete Works- Reduction in the length of the dissipation pool linedwith concrete, from 58.00 m to 38.00 m; a decisionresulting from the tests on the two-dimensional, hydraulicmodels with the scale of 1:60, and the general threedimensional model with a scale of 1:120, also reflectedin the lateral walls. The thickness of the slab was reducedform 2.00 m to 1.50 m.

Figure 8 - Jobsite Industrial Yard


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Figure 9 - Time Schedule - Concrete Histogram

- Optimization of the conduits in the water intakes and inthe draft tubes.- Reduction of the volumes of the erection bay.- Elimination of the intermediate platforms which lackedfunction in the upstream region of the water intake anderection bay structures.- Reduction of the volumes of the dam in the river bed,mainly resulting from the reduced length and alterationsto the elevations of the foundation.- General optimizations of the cross-sections of the typicalblocks.

• Earth / Rockfill Works- Optimization in the construction of the first phase - firststage cofferdam, when subject to low water levels duringthe construction period, which permitted the eliminationof the initially contemplated pre-cofferdam.- Raising the foundation elevation in the erection arearesulting in rock excavation economies.- Optimization of the excavation elevations in thegeometry of the tailrace channel.- General optimizations in the cross-sections of thecofferdams of the earth and/or rockfill.

The total of the optimizations led to importantreductions in the volumes executed, of which the principalones were:

Concrete 155,000 m3

Common excavation 175,000 m3

Open air rock excavation 614,000 m3

Compacted embankments, including rockfill 382,000 m3

Removal of cofferdams 304,000 m3

In financial terms, these optimizations led to areduction of US$ 29.4 Millions in the costs of the job. Inaccordance with contractual dispositions, this reductionwas shared with the contracting firms in the proportion of45% for the constructors and 10% for the consulting firm.These dispositions certainly contributed to the scope ofthe optimizations, with favourable results also reflectedin the terms for the execution.

7. ENVIRONMENTAL, SOCIAL ANDECONOMIC

7.1. Basic Environmental Programmes ImplementedThirty-three environmental programmes and around

400 million reais in environmental investments - neverbefore in Brazil was a hydroelectric power enterpriseinvolved in so many environmental actions.

During the construction of the plant and during thesubsequent years of operation, the following Basic


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Environmental Programmes - PBAs were implemented:1 - System for monitoring: local climate, water levels,seismology and, sedimentology;2 - Hydrogeological monitoring;3 - Monitoring and stabilization of slopes;4 - Research on alternative quarries;5 - Research and management: flora, wildlife, turtles anddolphins;6 - Implantation of Conservation Units;7 - Deforestation and cleaning of the reservoir area;8 - Reservoir protection belt: zoning and reforestation;9 - Limnological monitoring;10 - Research on the ichthyofauna;11 - Conservation of fish fauna;12 - Environmental education;13 - Prevention of accidents with poisonous species;14 - Acquisition of urban rural areas;15 - Reconstitution and improvement of the highway,electrical and sanitary infrastructure;16 - Reconstitution and improvement of the social andservice infrastructure affected by the reservoir;17 - Reurbanization of the coastal belt of PortoNacional;18 - Plan for the reurbanization of Lajeado and Miracemado Tocantins;19 - Adaptation of the public services during theconstruction;20 - Adaptation of economic services;21 - Reconstitution and enlargement of the areas fortourism and leisure;22 - Relocation and resettlement of the urbanpopulation;23 - Relocation and resettlement of the ruralpopulation;24 - Public health programme;25 - Monitoring of the population resettlements;26 - Archaeological rescue;27 - Programme for the Xerente native population;28 - Programme of dissemination and information;29 - Relocation of the Palmas sanitary dump;30 - Recuperation plan for degraded areas;31 - Resettlement of the population of Lajeadinho and ofthe rural population affected by the construction;32 - Medical and sanitation attention and health educationfor the population directly affected by the job;33 - Environmental specifications of the construction.

7.2. Relevant Aspects in the Environmental AreaSince obtaining the Installation Licence - LI, issued

by the Tocantins Nature Institute - NATURATINS in Juneof 1998, intense activities were developed with the aim ofmitigating and compensating the negative impacts andempowering the positive impacts resulting from theimplantation of the power plant.

Before the beginning of the works, the environmentalspecifications to be observed by the Contractor weredefined, covering aspects such as drainage,

geotechnology and embankments, highways and accessroads, water supply, collection and disposal of wastes,traffic, operation of machinery and equipment, sign-posting, deforestation. Special attention was given to theaspects of labour mobilization and relations with theexisting native community immediately downstream ofthe power plant. In relation to the medical, sanitary andhealth education of the jobsite population, actions of healthprotection, promotion and recuperation were developedwith the aim of making early diagnoses, and providingadequate therapeutical treatment, maintaining it as theentrance door to the health system of the State ofTocantins.

A plan for the recuperation of degraded areas wasalso prepared, embracing the jobsite, the encampment,the borrow and spoil areas, and the sand extraction beds.In the first place, procedures were defined with the objectof minimizing impacts and, in the second place, a planwas developed for replanting the area, which, after approvalby the NATURATINS, was put into practice.

The following activities were developed for the bioticmedium:

• Research and Management of the Flora and Faunainvolving the following works:- Floral and phyto-sociological surveys in the area ofinfluence of the Luís Eduardo Magalhães HPP with thecollection of genetic material and epiphytes;- Monitoring and rescue of the wildlife during the phasesof deforestation and filling of the reservoir and, ascomplementation, monitoring was executed of theentomological fauna, entomo-malacological monitoring,monitoring of arachnids and centipedes, in addition to aprogramme for accompanying the re-colonization ofalligator and iguana lizard species, and a programme forpreserving the species of herpetological fauna.- Identification and protection of the egg-laying sites ofturtles, including a programme of environmental educationand the collection of turtle eggs and hatchlings.- Dolphin monitoring, comprising focal sampling, trackingsampling and instantaneous monitoring.

• Ichthyofauna research, involving standardisedcollections with the aim of studying the fish communitiesand surveying the spawning areas and natural nurseriesin the phases of the natural river, the filling and thereservoir.

• Conservation of the Fish Fauna, involving the savingof the fishes during the 2nd phase of the river diversionand during the shutdowns of the generator units. A fishladder was also installed with the aim of permitting thetransposition of the migratory species. At present, studiesare still underway to evaluate the efficiency of thetransposition mechanism.

• Deforestation and Cleaning of the Reservoir AreaAfter the demarcation in the field of the flooding level,

the Plan of Dissemination and the EnvironmentalEducation Programme and the teams surveying theaffected population issued information addressed to the


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proprietors of the areas neighbouring the reservoir and tothe local residents, concerning the possibility of exploitingthe existing lumber in the area to be flooded.43,000 hectares of vegetation were deforested, comprisingdegraded and anthropic lands, scrub and swampland.With the aim of promoting the repopulation of the fauna,the sequence of the cuts followed the direction fromdownstream towards the upstream and from the lowerelevations to the higher.

After filling the reservoir, NATURATINS recommendedcleaning the floating materials (trunks and branches thatcould not be burned) and the additional deforestation ofmore than 6,000 ha with a view to scenic landscaperestoration.

• Reservoir Protection Belt: Zoning and Reforestation INVESTCO prepared the "Plan of Conservation and

Multiple Uses of the Luís Eduardo Magalhães HPPReservoir and its Surroundings" contemplating a macrovision of its zoning. The reforestation is underway of anapproximate area of 325 ha on the border of the reservoir,involving production activities of seedlings, transplantsand plant maintenance.

The following programmes were developed for thesocial economical medium:

• Acquisition of Rural Areas larger than 80 haThe acquisition process of rural areas with extensions

greater than 80 ha was promoted in the municipalities ofMiracema do Tocantins, Lajeado, Palmas, PortoNacional, Brejinho de Nazaré and Ipueiras, embracing272 properties for a total of 96,755.6083 ha.

• Relocation of the Rural Population362 families, between proprietors and occupants were

relocated into 12 settlements located in the Municipalitiesof Ipueiras (1), Brejinho de Nazaré (1), Porto Nacional(6), Monte do Carmo (1), Porto Nacional and Palmas(1), Lajeado (1) and Miracema and Miranorte (1).

Residences were built in accordance with the familycomposition, equipped with hydraulic, sanitary andelectrical installations. Specific collective structures werealso implanted in each resettlement, covering accesses,recreation areas, community centres, etc. A Plan of RuralDevelopment was developed to guide the productionsystems of the settlements.

• Relocation of the Urban Population587 families were relocated to 12 collective

resettlement areas in the municipalities of Palmas, PortoNacional, Miracema, Ipueiras and other dispersedlocations, in the director plan of Palmas, Miracema,Brejinho de Nazaré, Lajeado and Porto Nacional.Residences and also institutional works, such aschurches, schools, first aid posts and police stations,when they existed in the urban areas affected by thereservoir, were duly relocated.

• Evaluation and Monitoring of Population RelocationsThis programme refers to the accompaniment of the

collective resettlement projects, in the urban and ruralareas, with a view to evaluating and implanting the

projects, their effects as well as their subsequentperformance, with the objective of correcting directionsin the process.

• Reconstitution and Improvement of the Highway,Electrical and Sanitary Infrastructure

The following services were executed with a view toimproving the infrastructure of the surroundings of thereservoir.- Relocation of 10 km of the TO-010 Palmas-Lajeadohighway.- Implantation of a ferry-boat in Palmas until theconclusion of the works of the reinforced concrete bridgeover the reservoir.- Seven raisings of the crossings over streams,3 protections of embankments beside the reservoir,relocation of 97 km of roads and 10 bridges for theimprovement of local roads, implantation of 1 catwalkand reinforcement of a bridge.- Relocation of the 138 kV TL between Palmas and theMiracema Substation.- Improvement of stretches of the 69 kV TL from PortoNacional to Paraíso- Relocation of stretches of the 34,5 kV TL from Lajeadoto Palmas- Implantation of 24 km of sewage collection networkand 7 pumping stations, up to the Sewage TreatmentStation in Porto Nacional- Preparation of the design for the new sanitary dump ofPalmas, for construction by the City Hall andimplementation of the activities necessary for theshutdown of the then existing dump.

• Reconstitution and Improvement of the Social andServices Infrastructure affected by the Reservoir

The following services were executed with the aim ofreconstituting the infrastructure affected by the reservoir- Replacement of 4 schools- Replacement of 5 religious temples- Replacement of 3 first aid stations- Relocation of 2 cemeteries- Replacement of 2 community halls- Replacement of 1 Military Police post

• Plans for the Reurbanization of Lajeado and Miracemado Tocantins

A covenant was signed with the UNITINS for theexecution of the Plans of Reurbanization of the cities ofLajeado and Miracema do Tocantins, with a view topreparing the plan of territorial organization ofmunicipalities, considering the location of the power plant,its accesses and the lodgings for the personnel involvedin the construction, taking into account the plan of thecity and the need for expanding the recreation area, theimprovement of the highway accesses and of the publictransport, security, illumination, etc.

• Improvement of the Economic ActivitiesThe works were executed covering the reconstitution

and/or indemnity of the commercial activities andproduction of ceramics and the improvement of the


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commercial, industrial and services activities. Urban andrural establishments directly or indirectly affected by thereservoir were registered, followed by the immediateevaluations of the goods involved in order to define thealternatives for indemnities, relocation and eventualformation of stocks. Then, negotiations were opened forthe indemnity and/or replacement of the commercialactivity. In compensation, alternative extraction beds wereinvestigated in the area of influence of the power plant.Nine economically viable extraction beds were selected.

• Archaeological RescueMore than 300 archaeological sites were registered,

comprising lithic, ceramic, shelters, historical, and cavepaintings sites. During 5 years, the rescue comprisedarchaeological artefacts found both in the directly affectedarea and in the area influenced by the reservoir.

• Programme for the Xerente Native CommunityAn ethnic-environmental diagnosis was prepared

covering the Xerente and Funil Native Reservations, withthe purpose of supporting the preparation and detailingof the actions over the short, medium and long term. TheINVESTCO furthermore financed the Emergency Projectof Alimentary Security - PESA, with a view to providingthe Xerente community with subsistence plantings,mechanised plantings and high density vegetablegardens, together with the planting of fruit trees. The publichealth structure was reinforced with the construction ofthree infirmaries in the aboriginal stations.

• Environmental EducationThe PEAL - Environmental Education Programme of

the Luís Eduardo Magalhães HPP developed anunprecedented feature in the State of Tocantins, basedon a coordination covering all the action strategies, thougha Coordination Group formed between private initiative,environmental NGOs, state and federal organs.

A further approach of the programme was to informthe communities, through the schools of the targetedmunicipalities, of the environmental changes that wouldtake place with the formation of the reservoir and todiscuss these changes, as well as to show the measuresadopted to minimize the various impacts and possibleactions that the communities can adopt in theirinteractions with the environment to produce benefits,by the use of non-destructive models.

• Plan of Dissemination and Information- The plan aimed at the dissemination of information

concerning the power plant, targeting the affectedpopulations of the rural and urban areas, communityassociations, non-governmental organizations and civilsociety defence entities. Presentations were made ofthe plans and of the principal information of collectiveinterest in all the City Halls of the affected municipalities,as well as in the urban centres Lajeadinho, Vila Canela,Vila Graciosa and Pinheirópolis

8. PERFORMANCE OF THE ENTERPRISE

8.1. Analysis of the Behaviour of the ConcreteStructures and their Foundations

For monitoring the concrete structures and theirrespective foundations, a set of instruments was installedcomprising tube piezometers, multiple shaftextensometers, tri-orthogonal jointmeters, pore pressuregauges, flowmeters and thermometers.

These instruments were strategically distributed inthe concrete of the structures and foundations, in amanner to fulfil the double purpose of verifying thebehaviour during the construction phase and the beginningof operation, and of controlling displacements and thedevelopment of hydraulic pressures and flows during theentire period of the service life of the power plant. Thegreat majority of the instruments, distributed as indicatedin the Table 2, were used for both cases.

During the construction phase, the analyses of thereadings were made practically continuously. After thereservoir filling and entry into operation of the power plant,the readings began being taken with variable frequencyaccording to the type of instrument and its performance.Initially made every three months, the analyses are noweffected once a year, always accompanied by localinspections of all the structures.

After almost seven years since the filling of thereservoir (which occurred in September of 2001), it canbe affirmed that the behaviour of the concrete structuresand their foundations is considered to be fully satisfactory.

The blocks of the concrete structures present goodconditions with regard to uplift pressures. Only someisolated occurrences have been recorded, since in onlyone case was it necessary to intervene with correctivemeasures. It was the specific case of the water intakeblock TA-01, in whose foundation, after a period of almostthree years of stability, a piezometer at the concrete-

Table 2 - Distribution of instrumentation in the diverse structures


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rock contact commenced to indicate an increase in upliftpressure, reaching values very close to the so-called"attention level".

The piezometric evolution in the foundation of thisblock, and the flow of the drainage system were keptunder stricter vigilance, observing that after close to ayear the uplift pressure again presented a new increase.In addition to this, another piezometer situated belowthe first also began indicating an increase in thepiezometric pressure.

In the last three months of 2005 it was decided tointervene in the process, promoting a general check ofthe conditions of cleanliness of the drainage system ofthis block. Since nothing abnormal was found, it wasdecided to execute some additional drains, oriented tocross the general direction of the drainage system of theproject. After opening only five holes, the uplift pressureabruptly fell in both piezometers, although the flow in thenew drains remained at almost insignificant levels. Figure10 illustrates the evolution of the uplift pressures in thisstructural block.

In the remaining structural blocks only a few isolatedinstruments presented piezometric values close to the"limits of attention", but with a stabilized behaviour, notconstituting a significant problem in the general schemeof the uplift pressure distributions in the block.

With regard to the displacements in the foundation,the values recorded during the period by the rodextensometers depict a situation of total stability in allthe instruments. At the same time, in absolute terms,the displacements can be considered very small in allthe instruments, indicating uniform behaviour and goodquality of the foundation, in general.

The Table 3 presents, in synthesis, the totalaccumulated displacements recorded up to November

of 2006. The graph of Figure 11 presents the typicalbehaviour recorded by the extensometer installed in thefoundation of the RCC dam.

The triorthogonal jointmeters also presented, in ageneral manner, block displacements compatible withthe expectations. The graphs show that some of theblocks have still not achieved equilibrium with the meanambient temperature and, for this reason, are stillrecording small increases in the openings of thecontraction joints, principally in the months of milderclimate. Figure 12 presents this type of behaviour. Nomore important occurrence was recorded.

With regard to the total flow measured by theflowmeters, it was well below the design maximum limitvalues and the instruments are functioning adequately,indicating the tendency to reduce the seepage flows (seeFigure 13). The absence of a corresponding increase inthe foundation uplift pressures is an indication of thereduction in the permeability of the foundations to the"entry" of infiltration water. In conclusion, theinstrumentation installed shows that the structures arebehaving as expected.

Table 3 - Variations recorded by the deepest rod (rod 1) of the multiple rod extensometers from the commencement of readings until28/11/2006.

Figure 10 - Uplift Pressure in the Foundation of Block TA-01 ofthe Intake


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Figure 11 - Displacements in the Foundation of Block B-25of the RCC Dam

Figure 12 - Displacements Recorded by the Triorthogonal Jointmeter between TwoBlocks of the Intake

Figure 13 - Seepage Flows in the Connecting Wall


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8.2. Analysis of the Behaviour of the Earthfill andRockfill Structures

Table 4 lists the types and the numbers of instrumentsinstalled for monitoring the foundations, embankmentsand interfaces of the clay cores with the concretestructures.

Immediately after the filling, greater attention wasdirected to the recordings of the piezometric levelsmeasured at both earth-concrete interfaces subjected tomonitoring. This verification led to the installation of otherpiezometers, with the objective of supporting theinterpretation of the behaviour of the percolation in thesecontact regions.

Close to the erection bay structure there is evidenceof an earth embankment with a more heterogeneoushydraulic conductivity, suggesting a more permeableearthfill zone at the mid-height of the dam. In the oppositebank the monitoring of the contact with the concrete damindicated a more favourable behaviour, despite there alsobeing evidence of deficiencies in the earth-concretecontact in the upstream end of the core. The most recentyears of monitoring these regions have presented a water

Table 4 - Instruments installed in the Earth and Rockfill Structures(*) Instruments installed after the filling of the reservoir

Figure 14 - Typical Monitored Section of the Earth Dam

flow with stable behaviours since the water level in thereservoir undergoes insignificant variations over time.

The clayey core monitored in the earth dam of the leftbank, conceived containing compacted soil in the centralzone and outer rockfill wedges, presents a gooddistribution of the equipotential lines, revealing hydraulicgradients that are more uniform and compatible with thoseof compacted embankments of good homogeneity.

The foundation piezometers continue indicatingpiezometric levels in agreement with those admitted inthe design assumptions and, as expected, the inferencesof the piezometers demonstrate a significant efficiencyof the sealing trench that intercepts the layer of alluvialsoil of the foundation.

Periodical inspection of the earth and rockfillstructures, as well as the analyses of the instrumentreadings reveal a stable behaviour without any anomaly,practically six years after the filling of the reservoir.

Figure 14 shows a typical monitored section of theright bank earth dam and Figure 15 shows the behaviourof the corresponding piezometric levels.


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9. TECHNICAL FEATURES

Location Municipalities of Miracema do Tocantins/Lajeado - State of Tocantins

Latitude 09º45’26”Longitude 48º22’17”

Year of start July of 1998

Entry into commercial operation01/12/2001 - 1st Unit01/03/2002 - 2nd Unit09/05/2002 - 3rd Unit30/07/2002 - 4th Unit07/11/2002 - 5th Unit

Proprietor INVESTCO S.A., constitutedby the firms:

REDE Lajeado Energia S.A. 45.35%EDP Lajeado Energia S.A. 27.65%CEB Lajeado Energia S.A. 20.00%Paulista Lajeado Energia S.A. 7.00%Designer Themag Engenharia e Gerenciamento Ltda.

Contractor CCL - Consórcio Construtor do UHELajeado constituted by the firms:

- CONSTRUTORA ANDRADE GUTIERREZ S.A. and- CONSTRUTURA NORBERTO ODEBRECHT S.A.

Manufacturers & Erectors CELAJ - ConsórcioEletromecânico

Lajeado constituted by the firms:- VOITH SIEMENS HYDRO

POWER GENERATION LTDA.- BARDELLA S.A., with subcontractors

for equipment erection the firms:ENESA Engenharia S.A.ENERCAMP Engenharia

Basic DataArea of the hydrographical basin 184,219 km2

Annual mean precipitation 1,800 mmAnnual mean temperature 25.9º C

ReservoirArea at maximum normal level 630 km2

Total volume 5.193 x 109 m3

Active volume 0.48 x 109 m3

Length 167.5 kmMaximum width 8.4 kmMean depth 8.00 mMaximum normal water level 212.30 mMaximum exceptional water level 212.60 mMinimum water level 211.50 m

Tailrace channelMaximum normal water level 187.20 mMaximum exceptional water level 201.50 mMinimum water level 173.20 m

FlowsMean incoming flow 2,523.00 m3/sMaximum recorded flow (24/02/1980) 28,558.00 m3/sMinimum daily flow recorded (19/10/1994) 263.00 m3/sMaximum diversion flow 23,019.00 / 26,161.00 m3/sTime of recurrence 25 / 50 YearsMaximum incoming flow - ten thousand year 49,870.00 m3/s

DamType Earth/rockfill/Roller C. ConcreteLength 2,034.43 mMaximum height 74.00 mCrest elevation 215.00 mWidth at the crest 10.00 m

SpillwayType surfaceLength 323.00 mDesign flow 49,870.00 m3/s

Spillway GatesType RadialNumber 14Dimensions:-Width 17.00 m- Height 23.50 mManufacturer BARDELLA

Water IntakeType Incorporated to powerhouseLength 142.50 mMaximum height 74.00 m

Figure 15 - Piezometric Levels in the Foundation of the Earth Dam


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Water Intake GatesType Fixed wheelNumber 5 X 3Dimensions:- Width 5.65 m- Height 15.50 mManufacturer BARDELLA

River DiversionType 6 Lowered Spillway Bays

PowerhouseType ShelteredWidth 50.52 mLength 142.50 mInstalled capacity 902.50 MW

TurbinesType Kaplan with vertical shaftNumber of units 5Rated power 180.50 MWRated head 29.00 mMaximum discharge per unit 660.00 m3/sRated speed 100 rpmManufacturer VOITH

GeneratorsType SynchronousRated power 190 MVAVoltage 13.8 kVFrequency 60 HzRotation 100 rpmManufacturer SIEMENS

Step-up TransformersNumber 5Type Three-phase - submerged in insulating oilRated power 190 MVAVoltage 13.8 - 230 kVManufacturer SIEMENS

QuantitiesExcavation in soil 3,213,750 m3

Excavation in rock 3,813,020 m3

Compacted clay and rockfill 790,400m3

Concrete (RCC & Conventional) 1,243,074m3

Reinforcing steel 61,000 t

luis eduardo magalhƒes - lajeado hydroelectric power

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