Geomembrane sealing systems for dams: ICOLD … · TECHNICAL PAPER Geomembrane sealing systems for dams: ICOLD Bulletin 135 Alberto Scuero1 • Gabriella Vaschetti1 Received: 3 May

TECHNICAL PAPER

Geomembrane sealing systems for dams: ICOLD Bulletin 135

Alberto Scuero1 • Gabriella Vaschetti1

Received: 3 May 2017 / Accepted: 2 June 2017 / Published online: 20 June 2017

� Springer International Publishing AG 2017

Abstract The paper presents the contents of the latest

bulletin published by the International Commission on

Large Dams (ICOLD) on the subject of geomembranes as

sealing systems for dams. Bulletin 135, published in 2010,

is an updating and expansion of ICOLD Bulletins 38,

published in 1981, and 78, published in 1991. Bulletin 135

has been prepared, under the aegis of the ICOLD Com-

mittee on Materials for Fill Dams, by the ad-hoc European

Working Group for geomembranes and geosynthetics as

facing materials, composed by experts from nine European

countries, with external contribution from USA. Different

competences were covered by the group, which included

geomembrane scientists, dam designers, geomembrane

systems designers, dam owners, and geomembrane spe-

cialist contractors. The bulletin is composed of 9 chapters,

in total 464 pages for the English and the French versions.

The paper outlines the history of the constitution of the

working group, the preparation of the database on

geomembrane systems in dams all over the world, dis-

cusses the topics covered by each chapter, and gives some

statistics based on the database. Some case histories men-

tioned in the Bulletin, and recent developments, are also

presented.

Keywords Geomembrane � Waterproofing � Dams � PVC �ICOLD

Introduction and background

The use of geomembranes in hydraulic structures has more

than half-century history: geomembranes were first used in

canals immediately after the Second World War, in the

research and field experimentation carried out by the US

Bureau of Reclamation on various types of canal linings

since 1946. In dams the use of geomembranes started in

1959 at Contrada Sabetta fill dam in Italy. The first

applications were made in construction of new fill dams,

which being intrinsically pervious need a separate com-

ponent to provide imperviousness. The concept of using

synthetic impervious geomembranes instead than conven-

tional impervious materials such as clay, concrete or

asphalt concrete, certainly derived, among other consider-

ations, from the good performance of embedded polyvinyl

chloride (PVC) waterstops in the huge number of concrete

dams worldwide that rely on their use to stop water infil-

tration at joints. A geomembrane system on the upstream

face of a dam can be considered, from a conceptual point of

view, as one wide waterstop sealed at the abutments and

bottom.

In the early 1970s, the use of geomembranes was

extended to the rehabilitation of old concrete dams, and in

the early 1980s to the waterproofing of new Roller Com-

pacted Concrete (RCC) dams. At present geomembranes

are adopted all over the world to waterproof all types of old

and new dams (concrete gravity dams, buttress dams, arch

dams, multiple arch dams, rockfill dams with concrete

facing, rockfill dams with asphalt facing, earthfill dams,

tailings dams, RCC dams), and practically all types of

This paper was selected from GeoMEast 2017–Sustainable Civil

Infrastructures: Innovative Infrastructure Geotechnology.

& Gabriella Vaschetti

[email protected]

Alberto Scuero

[email protected]

1 Carpi Tech, Balerna, Switzerland

123

Innov. Infrastruct. Solut. (2017) 2:29

DOI 10.1007/s41062-017-0089-0

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hydraulic structures (canals, hydraulic tunnels, surge

shafts, pumped storage reservoirs, forebay reservoirs,

underground tanks, etc.). The issue of the use of

geomembranes on dams, which are among the most

demanding and critical hydraulic structures, has been

addressed by ICOLD, the International Commission on

Large Dams, in two theme bulletins.

Bulletin 38 (1981)

Bulletin 38, ‘‘Use of thin membranes in fill dams’’ [1], was

published in 1981. Bulletin 38 defined geomembranes as a

‘‘thin product with a thickness from one to a few mil-

limetres, constituted of a flexible watertight material…[that]… may be prefabricated at works and then trans-

ported to the site, or prepared and positioned directly on the

site (in situ)’’; it considered a cover layer mandatory for a

geomembrane system; and recommended a height of 30 m,

and a surface of modest dimensions. Increasing the limit

height to 40 m was deemed to be based on foreseen future

improvements in technique and materials.

Bulletin 78 (1991)

As the use of geomembranes increased and gradually

extended to the rehabilitation of all types of existing dams,

and to waterproofing of the new Roller Compacted Concrete

damswhich began being built in the early 1980s, the need for

an updating of the bulletin was felt. In 1991 ICOLD pub-

lished a new theme bulletin, Bulletin 78, ‘‘Watertight

geomembranes for dams—State of the art’’ [2]. Bulletin 78

considers geomembranes an established technique for new

construction and rehabilitation of fill dams, as an emerging

application for rehabilitation of concrete and masonry dams,

and as ‘‘Future prospects’’ in application to new RCC dams;

the cover layer is no more considered necessary; and con-

cerning the limit height ‘‘There is no reason to recommend a

specific height limitation on the use of geomembranes in

embankment dams’’.

After 1991, the use of geomembranes to waterproof new

dams and to restore imperviousness in old dams further

increased. Europe, where the majority of dams are old, was

one of the main users and developers of geomembrane

systems. In European countries the need for increased

information on current practice and trends was more deeply

felt. In 1993, during a symposium on dam rehabilitation

organised by the ICOLD French National Committee in

Chambery, a European Working Group for geomembranes

and geosynthetics as facing materials was established, with

the mission of investigating the behaviour of geomembrane

systems installed in previous times, and of ascertaining and

assessing the most recent developments in new projects.

The Group was formed by members of the ICOLD

National Committees of Austria, France, Germany, Italy,

Portugal, Switzerland, and the United Kingdom, and by

experts from the Czech Republic, France, Italy, and Spain.

All competences were covered: the group included

geomembrane scientists, dam designers, geomembrane

systems designers, dam owners, and geomembrane spe-

cialist contractors. The decision was taken to create a

database collecting the most relevant information on

geomembrane systems already in service on dams. The

next chapter details how the database was compiled. In the

years that followed, the database included[80 European

dams, and then it was gradually extended to include case

histories also from countries outside Europe.

The start and completion process of Bulletin 135

At the ICOLD Executive Meeting in Antalya in 1999, the

ICOLD Committee onMaterials for Fill Dams, under whose

aegis Bulletins 38 and 78 had been published, discussed the

data collected by the working group and decided to amplify

the information and make it available to the international

dam community. The Committee extended the working

group to include worldwide leading experts in the field of

geomembranes, and gave it an official mandate to prepare a

new bulletin on geomembranes, addressing design, manu-

facturing, installation, quality control and contractual

aspects, and to extend the database to the whole world.

Database

The database was implemented starting from some data

already included in Bulletins 38 and 78, and from the initial

database created by circulating through the members of the

working group among owners of dams the technical form

elaborated for this purpose. The technical form is a 6-pages

document consisting of:

• Section A:Main information, containing data on the dam

(characteristics and service conditions), type of geomem-

brane and characteristics of the geomembrane system,

and the owner’s comments on efficiency, durability,

technical and economical effectiveness of the system

• Section B: Additional information, mainly adding data

on features of geomembrane system, and on geomem-

brane installation, quality control and costs.

To implement incomplete forms, or to collect data of

dams for which forms were not available from the owner or

its consultants, data from international literature (Pro-

ceedings of ICOLD Congresses, Executive Meetings,

Conferences of National Committees, Conferences of

ASDSO, the US American Society of Dam Safety Offi-

cials, articles in specialised publications such as Reservoirs

29 Page 2 of 17 Innov. Infrastruct. Solut. (2017) 2:29

123

and Dam of the UK National Committee, Bulletin of the

Australian National Committee), and personal communi-

cations by designers and University professors, were used.

Work method

After the contents of the bulletin had been discussed and

agreed by all members in the first plenary meetings, smaller

groupswere created toprepare thevarious chapters in function

of their competence. Periodical meetings were used so that all

or most of the members of the group could peruse, make

comments and refine the parts prepared by the smaller groups.

The findings of the database served as permanent comparison

and also to evaluate evolutions of the geomembrane sealing

systems if any. Drafts of completed chapters were circulated

internally to gather comments from all members.

When the first complete draft in English was ready, it was

submitted to the Committee on Materials for Fill Dams,

during the Executive Meeting of 2001. The final version in

English was approved by the Committee in 2005.

The French National Committee requested that the 209

pages of the approved final English version be translated in

French and the bulletin published in both languages. The

final French version was completed in 2008. More than

1 year was required for final revision and approval. Bul-

letin 135 was published in 2010, with the title

‘‘Geomembrane Sealing Systems for Dams–Design prin-

ciples and review of experience’’. In total 464 pages,

inclusive of 17 pages of terminology and 14 pages of

bibliography and most common standards.

Bulletin 135

The foreword of the bulletin [3], written by Mr. Marulanda,

Chairman of the Committee on Materials for Fill Dams, is

well in the context of the history of geomembranes sealing

systems in dams.

Foreword of the bulletin

The first edition of this Bulletin was issued in 1981 as Bull.

38 (*). It was a precise, detailed technical guide with

comprehensive references: types of membranes along with

their features were reviewed as well as theoretical and

actual strains involved; procedures to be developed were

detailed with examples.

In 1991, the new Bulletin 78, ‘‘Watertight Geomem-

branes for Dams. State of The Art’’ (**) cited 70 dams

incorporating geomembranes and it focused on new and

improved materials which in the meanwhile became

available and on the experience gained which has resulted

in a better understanding of their use and in advanced

engineering skills in this field so that they have been used

in higher dams than before. The Bulletin 78 dealt with new

areas such as enhancing the water retaining performance of

other facings, repairing old gravity dams and the deterio-

rated upstream concrete facings of fill dams. Finally, Bul-

letin 78 reported new ideas regarding drainage, supporting

layer and protective covering and geomembranes which

were at that time (1990) under consideration for the

upstream facings to roller compacted concrete dams.

This new edition in 2010 cites 280 dams and updates the

data and recommendations of the first two 38 and 78

Bulletins. It reviews the new information and practices that

have appeared in the meantime, which include application

of geomembrane as the only watertight element in fill dams

(Bovilla, Albania, 91 m, 1996), in RCC dams (Miel 1,

Colombia, 188 m, 2002), as external joints on RCC dams

(Porce II, Colombia, 118 m, 2000), as underwater repair of

dams on gravity dams (Lost Creek, USA, 36 m,1997) and

on RCC dams (Platanovryssi, Greece, 95 m, 2002).

This new Bulletin also deals with application of

geomembranes for dams affected by AAR (Pracana, Por-

tugal, 65 m, 1992). The Bulletin reports about sealing of

defective joints and cracks in the upstream face of CFRDs

by strips of geomembranes mechanically fastened (Straw-

berry, USA, 101 m, 2002).

The 280 dams incorporating geomembranes cited in this

new Bulletin are 188 fill and 91 concrete ? RCC (?1 of

unknown type). Out of the 280 dams 48 are in USA, 47 in

China, 42 in France, 35 in Italy, 10 in Spain and inGermany, 9

inAustria, 6 in theCzechRepublic, 5 inPortugal, 4 inBulgaria

and in UK, 2 in Belgium, Cyprus, Romania, Slovakia and

Switzerland, 5 scattered in other European countries. Europe

and USA account for[67% of the total (188 dams). Because

of the large experience gained in Europe, this revision was

prepared by the EuropeanWorking Group onGeomembranes

as Facing Materials for dams, appointed by the International

Commission on Large Dams, with the assistance of some

experts from USA. This bulletin conveys to the reader a real

worldwide experience on use of geomembranes, with the

oldest now dating more than 45 years and still in service. The

authors deserve our warmest appreciation, and in particular

Alberto Scuero, co-ordinator of the Group, Gabriella

Vaschetti, Secretary, and some members of the Group, in

alphabetical order, Blanco, Cazzuffi, Girard, Koerner,

Lefranc, Millmore, Schewe, Sembenelli, Vale.

A.M. MARULANDA

Chairman,

Committee on Materials for Fill Dams

(*) Report prepared by R. Corda and H. Grassinger,

members of the Committee on Materials for Fill Dams,

with the assistance of K. Rienossl (Austrian National

Committee) and J. Combelles, J. Couprie, P. Huot, V. Lelu,

D. Loudiere and P. Paccard (French National Committee).

Innov. Infrastruct. Solut. (2017) 2:29 Page 3 of 17 29

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(**) Report prepared by R. Corda, member of the

Committee on Materials for Fill Dams, with the assistance

of G. Degoutte and C. Bernhard (CEMAGREF, France), L.

O. Timblin and W. R. Morrisson (USCOLD) and D. Caz-

zuffi (ENEL, Italy).

Contents of the bulletin

The bulletin has been structured in 9 chapters and 3

appendixes:

• Chapter 1: is an introduction to geosynthetics, to their

classification in several families according to their

function, and in general to their field of application

• Chapter 2: describes classification and characteristics of

the various types of geomembranes, and discusses

materials specifications and testing

• Chapter 3: discusses the loads and stresses to which

geomembranes are exposed, criteria and recommenda-

tions for design, construction and operation. The loads

and stresses relevant to a particular type of dam are

addressed in the relevant dedicated chapters.

• Chapter 4: discusses application of geomembranes in

construction of new fill dams, application of geomem-

branes to repair of asphalt-concrete sealing facings,

bituminous geomembrane facings, and concrete facings

in CFRD

• Chapter 5: discusses application of geomembranes to

repair of concrete, shotcrete and masonry facings of

gravity dams and arch dams. The chapter addresses

repair in the dry and underwater

• Chapter 6: discusses application of geomembranes to

RCC dams as watertight upstream facing in new

construction, and as repair of existing RCC dams

• Chapter 7: discusses special applications as watertight

element at joints and cracks, and as an underwater

repair measure

• Chapter 8: dedicated to quality control

• Chapter 9: gives recommendations for specification for

design, supply and construction, including guidance to

technical contents of contracts

• Appendix 1: the database, related to the ICOLD

definition of ‘‘large dam’’.

• Appendix 2: a list of geomembrane technology terms

and definitions (according to IGS–International

Geosynthetics Society)

• Appendix 3: bibliographic references and references on

testing standards.

The following paragraphs state, more formally, the

contents of the nine chapters and of the three Appendixes,

explaining the main issues for of each chapter.

Chapters 1 and 2: introduction and materials

The chapters address all geomembranes, i.e. materials

prefabricated in a factory, either in relatively thin contin-

uous polymeric sheets (polymeric geomembranes, with a

large predominance of PVC geomembranes), or by

impregnation of geotextiles with bituminous materials

(bituminous geomembranes). The geomembranes consid-

ered are factory-made polymeric and bituminous

geomembranes. In situ impregnated geotextiles and

sprayed liners based on polyurethane and polypropylene

resins, which are closer to the family of the resins and less

and less frequently used, are not subject of the bulletin. The

few existing examples have notwithstanding been included

in the database.

The chapters discuss materials’ composition, configu-

ration, supply, seaming, testing, durability and ageing, with

some statistics for each type of geomembrane (Table 1).

Overall, polymeric geomembranes account for[91% of

the total, out of which about 60% are PVC. Bituminous

geomembranes have been used only on 20 dams, of which

17 in covered position.

Chapter 3: loads acting on the GSS

This chapter describes the stresses and constraints to which

geomembranes are exposed when used as sealing element

in dams: mechanical, physical, chemical, biological and

other types of attacks. It offers criteria and recommenda-

tions to consider in the design, construction and operation

of dams with having a geomembrane as water barrier.

Identification and relevant and comprehensive characteri-

zation of all the stresses to which the geomembrane sealing

system will be submitted is essential to ensure the success

of the project.

Chapter 4: fill dams

This chapter deals with applications of geomembranes in

fill dams, where geomembranes have been used in 60% of

cases in new construction, in 40% as rehabilitation measure

of asphalt concrete facings and of concrete facings

(CFRDs). Approximately in 90% of dams, the geomem-

brane was installed in upstream position, to minimise

uplifts and uncontrolled water presence in the dam body,

improving stability and safety.

Generally speaking, the application of a PVC

geomembrane system in new fill dams has the significant

advantage that, being the geomembrane very deformable

(typically[230%), it can accommodate without breaking


123

the not negligible movements that are typical of this type of

dam, especially at the junctions between the deformable

dam body and the rigid concrete structures (e.g. spillways,

intakes, plinth), and the settlements that may still occur

after impoundment. New fill dams with geomembrane

systems are behaving quite well. In new construction, the

chapter discusses the various configurations: upstream

exposed, upstream partially or totally covered, and internal

position, including the cases of heightening of existing

dams, and giving examples for each configuration.

At publication of Bulletin 135, the most recent face

anchorage technique for upstream exposed geomembranes

was by seaming the PVC composite geomembrane liner to

PVC anchor strips embedded in porous concrete curbs

against which the fill was placed.

Sar Cheshmeh tailings dam raising was the first

embankment dam adopting this type of face anchorage

system. Sar Cheshmeh existing tailings storage in Iran,

owned by National Copper Industries Co., included a 75 m

high main embankment consisting of an inclined clay core

as impervious element, and of outer colluvial gravel shells.

The production escalation required a set up comprising a

39.5 m high and 1000 m long downstream raise to the

main embankment, in four separate stages, of which IIB

and IIC have been completed so far. Stability analysis

showed that the seismic stability of a raised clay core was

not sufficient, due to the geometry of the raising. Further-

more, no suitable clay based materials were available at

site. ATC Williams, designers of the dam raising, consid-

ered as alternative solutions an asphaltic core, an upstream

bituminous membrane, and polymeric geomembranes. An

upstream exposed PVC Geomembrane Facing Rockfill

Dam (GFRD) was selected because of superior safety in

respect to earthquakes. ATC Williams deemed the GFRD

system would be the most stable, efficient and buildable

arrangement.

The finishing layer of the dam is made with extruded

porous concrete curbs illustrated in the schemes of Fig. 1.

The face anchorage for the waterproofing liner is the

patented method with PVC anchor strips discussed above.

As the embankment and curbs were being raised, the PVC

strips were nailed to the curbs and then permanently

anchored by the fill compacted against the curbs. Over-

lapping PCV strips were joined by heat-seaming. The

procedure is shown in Fig. 3. The PVC geocomposite used

for the anchor strips and for the liner is SIBELON� CNT

4400, consisting of a 3 mm thick PVC geomembrane, heat-

bonded during manufacturing to a 500 g/m2 non-woven

polypropylene geotextile (Fig. 2).

The PVC strips heat-welded at the overlap, form con-

tinuous anchor lines. The SIBELON� geocomposite liner

sheets were then deployed from the crest, after having been

secured at top by a stainless steel batten strip on a con-

ventional concrete curb. After cleaning the PVC anchor

lines, the PVC geocomposite sheets were temporarily

anchored at the crest of the first stage, stage IIB, and then

unrolled down the slope (Fig. 4 on left). The PVC geo-

composite sheets were heat-welded to the PVC anchor

strips (Fig. 4 on right). Adjoining PVC geocomposite

sheets were watertight heat-welded at overlapping, as

shown in Fig. 4 at bottom.

The bottom seal of stage IIB was made by embedding

the PVC geocomposite in a trench excavated in the clay

core of the existing dam, and then backfilled with clay

(Fig. 5 on left). The bottom perimeter seal at the concrete

plinth of the abutments is mechanical, referred to as the tie-

down type. In tie-down seals, watertightness against water

in pressure is attained by compressing the PVC geocom-

posite unto the concrete with flat stainless steel batten strips

secured by stainless steel anchor rods embedded using

chemical glass anchoring capsules at regular spacing.

Smoothing epoxy resin, rubber gaskets, stainless steel bat

Table 1 (Table 3 in Bulletin

135)-Synthetic materials more

frequently employed as

geomembranes

Type Basic material Abbreviation

Thermoplastic Chlorinated polyethylene

Ethylene–vinyl acetate copolymer

Polyethylene

Polypropylene

Polyvinyl chloride

CPE

EVA/C

PEa

PP

PVC

Thermoplastic rubbers Chlorosulfonated polyethylene

Ethylene–propylene copolymer

CSPE

E/P

Thermo-set Polyisobutylene

Chloroprene rubber

Ethylene-propylene diene monomer

Butyl rubber

Nytrile rubber

PIB

CR

EPDM

IIR

NBR

a Within the group shown, polyethylene and polypropylene are collectively called polyolefins


123

ten strips and splice plates achieve even adequate com-

pression necessary for watertightness, as extensively

described in international literature (Fig. 5 on right).

The intermediate seal between stage IIB and stage IIC is

made by watertight welding the geocomposite of the upper

stage on the geocomposite lower stage, and covering the

Fig. 1 Upstream exposed geomembrane with PVC anchor strips (Carpi patent)

Fig. 2 Deployment of

waterproofing geocomposite

sheets on the PVC anchor strips

Fig. 3 PVC anchor strips embedded in curbs


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weld with a PVC geomembrane strip. The seal top of stage

IIC is made by embedding the geocomposite in a trench

then ballasted with conventional concrete as shown in

Fig. 6.

Stage IIB and staged IIC raisings reached 20 m of

height. Total surface was 38,500 m2. Installation of the

waterproofing system took 14 weeks in total (Fig. 7).

Fig. 4 Deployment and heat-welding of geocomposite sheets on PVC anchor lines, and heat-welding of adjacent sheets

Fig. 5 Bottom perimeter seal-embedded type (left) and the tie-down type (right)

Fig. 6 Intermediate seal between stage IIB and stage IIC (left) and top perimeter seal at stage IIC (right)


123

More dams have now been constructed with the same

system. A recent (2015/2016) example is Nam Ou VI 88 m

high rockfill dam, which is part of the Nam Ou VI

Hydropower Project in Lao PDR, and the highest GFRD in

Laos. The PVC geocomposite selected to ensure long-term

watertightness in exposed position is SIBELON� CNT

5250, consisting of a 3.5 mm thick PVC geomembrane,

heat-bonded during manufacturing to a 700 g/m2 non-wo-

ven polypropylene geotextile. The system was the same of

Sar Cheshmeh. The dam body and its waterproofing system

were constructed in three separate stages: stage 1 from the

bottom of the excavation at El. 427 m to El. 472.1 m, stage

2 to from El. 472.1 m to El. 512.1 m, and stage 3, com-

prising a 3 m high parapet wall, to reach El. 515.0 m.

Installation of the geomembrane system of stage 1 was

completed in 24 days for 13,700 m2 of upstream water

barrier; installation of the geomembrane system of stage 2

was completed in 28 days, for about 23,000 m2 of

upstream water barrier. In total, 52 days to construct a

watertight upstream facing of almost 37,000 m2, a fraction

of what a concrete facing would have required (Fig. 8).

An outstanding application of the same technology is

ongoing at Las Bambas copper mine currently developed in

Peru. Tailings from the mine processing plant are pumped

to a Tailings Storage Dam (TD) located within a broad

valley and formed by a large Tailings Retaining Embank-

ment on the southern and eastern sides. The TD will con-

tain all tailings generated from processing operations, all

bleed water released from the deposited tailings, and all

water runoff from the TD catchment. For mine start-up

purposes, the TD will be the primary water storage for the

commissioning of the concentrator plant. The TD will

continue to be utilized as water storage throughout the

operating life of the mine. The Tailings Retaining

Embankment, therefore, needs to be a water retaining

embankment, and is being built from rockfill and water-

proofed with an exposed PVC geocomposite, to construct a

GFRD.

The Tailings Retaining Embankment is being raised in

stages, and when completed will be 230 m high. Stage 1A

has an approximate height of 58 m, and total surface lined

is 39,767 m2; stage 1B has raised the embankment to a

maximum height of 88 m, and total surface lined is

138,129 m2. After completion of stage 1B the Carpi crews

were placed in standby until construction of the embank-

ment embedding the anchor strips in the curbs from

Fig. 7 Upstream exposed geomembrane at Sar Cheshmeh tailings dam in Iran

Fig. 8 Stage 1: stage 1 ? stage 2 waterproofing system completed in 52 days


123

elevation 4020 m to elevation 4050 m was completed,

around middle of November. Carpi started to install the

geocomposite system of this stage on 19 November 2016.

Installation is at present ongoing. Total surface to be lined

in this stage is 172,512 m2. The installation of the

geomembrane has already reached a height of 118 m from

the foundation (Fig. 9).

New patented technologies are recently being used for

upstream geomembrane systems in new fill dams, which

were not available at the time of publication of the bulletin.

Such technologies include face anchorage of the

geocomposite by deep grouted anchors, such as adopted at

Filiatrinos hardfill dam, and face anchorage by PVC anchor

strips embedded in trenches, such as adopted at Bulga

earthfill dam. The same systems were adopted at some of

the 18 Waters Saving Basins of the Panama Canal

Expansion. See Fig. 10.

Design aspects such as the characteristics and stability of

the various layers, the anchorage at boundaries, the

anchorage over the dam face, and installation techniques, are

analysed. Specific aspects for rehabilitation are the anchor-

age systems, designed depending on the type and strength of

Fig. 9 Stage 1: Las Bambas tailings dam at stage 1, and the dam pictured in November 2016

Fig. 10 Upstream exposed geomembrane anchored by deep grouted anchors (Filiatrinos hardfill dam, Greece 2015, left) and by trenches (Bulga

earth dam, Australia 2016, right, Panama Canal Expansion Water Saving Basins, bottom)


123

the existing facing (asphalt concrete or concrete). The var-

ious aspects to consider when deciding if to place a cover

layer on the geomembrane in a new fill dam are discussed, as

the possibility of damaging the geomembrane when placing

the cover was well known. The chapter discusses also

available alternatives for geomembranes in central position,

of which no photos were available at that time. See Fig. 11.

The rehabilitation of fill dams with concrete facing

(CFRD) and with asphalt concrete facing (ACFRD) is also

addressed. The exposed system (conceptually the same

described in ‘‘Chapter 5: concrete and masonry dams’’),

and the covered system are described.

Chapter 5: concrete and masonry dams

In concrete and masonry dams, geomembranes have been

used for rehabilitation. Only in one case of partial appli-

cation at heel, the geomembrane was used since new

construction. Almost all concrete and masonry dams that

have used geomembranes for rehabilitation have been

waterproofed with the systems patented by Carpi. Perfor-

mance history of this system is at present approaching

40 years, and field results have proven its capability of

extracting and discharging water already permeating the

concrete, for example at Pracana dam, where the exposed

PVC geomembrane has helped slowing the alkali-aggre-

gate reaction. Both the cases that follow are reported in

Bulletin 135.

Pracana is a 65 m high buttress dam in a seismic and hot

region of Portugal, built between 1948 and 1951. Ano-

malies in the behaviour of the dam were evident since first

impoundment: cracks appeared at the upstream and

downstream faces, significant seepage and carbonation at

the downstream face were observed. Unsatisfactory per-

formance of local repairs required lowering the reservoir

level. In 1997 EDP, Electricidade de Portugal, became the

owner of the dam, and put the dam out of operation to

thoroughly investigate its behaviour, its conditions, the

causes of deterioration, and to develop a rehabilitation

plan. Investigations ascertained that among concurrent

causes of cracking (deficiency in construction techniques,

thermal variations of concrete during construction, differ-

ential settlements of not-consolidated foundations) were

also expansive phenomena of concrete. A major concern

was related to the critical scenario relevant to sliding

conditions along horizontal cracks, especially considering

the uplifts. Expansion of concrete was further investigated

and ascertained the presence of alkali-aggregate reactions,

which further activated by infiltration of water from the

reservoir. Restoring and granting long-term imperviousness

to the upstream face, and reducing the uplifts, were

mandatory.

The large rehabilitation and refurbishment works at the

dam included an upstream drained waterproofing

geomembrane, to stop water infiltration, to avoid that water

in pressure could act on the horizontal cracks, and to

deprive the dam of its water content; construction of a new

grouting plinth and of two sets of struts between buttresses

at the downstream face, to improve stability; treatment of

foundations, including execution of a new grout curtain;

construction of a new auxiliary spillway, to improve

behaviour and safety in respect to extreme floods, and of a

new water intake, and concrete treatment, consisting of

individual cement grouting for larger cracks and mass

grouting with epoxy resin for smaller cracks.

The exposed drained PVC geomembrane system was

installed in the dry season of 1992, concurrent with the

huge civil works. To enhance drainage capability a drai-

nage geonet was placed on the entire surface then covered

by the waterproofing geocomposite (Fig. 12 on left). The

drainage system was divided in 10 separate compartments

Fig. 11 Upstream covered geomembrane (Bovilla gravel dam, Albania 1996, left) and central zigzag geomembrane (Gibe III cofferdam,

Ethiopia 2009, right)


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for the water drained from the upstream face of the dam,

and a separate compartment for the water coming from

foundations.

At bottom, the perimeter seal was installed on the new

foundation plinth, achieving connection of the liner with

the new grout curtain, so that the water barrier is contin-

uous from crest down to deep impermeable foundations.

Watertight perimeter seals were placed also around intake

and outlets, and at the rails for operation of the gates.

The PVC geocomposite SIBELON� CNT 3750, con-

sisting of a 2.5 mm thick PVC geomembrane, heat-bonded

during manufacturing to a 500 g/m2 non-woven geotextile,

is anchored by Carpi patented tensioning profiles (Fig. 12

on right, an excerpt of ICOLD Bulletin 135), placed at

1.8 m spacing, and by a watertight perimeter seal of the tie-

down type already discussed. The regularising resin, rubber

gaskets and stainless steel splice plates allow achieving the

even compression that grants the watertightness.

The tensioning system is designed to maintain the liner

in a stable position, to tension it, avoiding formation of

slack areas and folds, and to keep it independent from the

dam face, allowing and facilitating drainage of water

between the dam and the geocomposite by creating an air

space between the upstream face of the dam and the

geocomposite.

The waterproofing system was installed in 5 months, for

a total of 7900 m2. Reported total leaks, from upstream

face and from foundations, are less than 0.34 l/s. Since

1992, in addition to monitoring the performance of the

geocomposite system and its effectiveness in respect to

leakage control, EDP has been monitoring the behaviour of

the dam, to ascertain the capability of the system to

dehydrate the dam body, reducing the water content feed-

ing the AAR. LNEC, the National Laboratory for Civil

Engineering, is in charge of studying the swelling reactions

through various measuring systems. The details of the

monitoring systems and of the findings of the study can be

found in the exhaustive paper presented by EDP at the 21st

Congress of ICOLD in Montreal (Liberal et al. [5]. In the

final conclusions of the paper, EDP reports that ‘‘A sig-

nificant gradual reduction of the swelling rate was observed

[omissis] and the concrete dam waterproofing may be

assumed to contribute for the reduction of the swelling

process’’ (Fig. 13).

In 2017, during the oral presentation made by EDP (S.

Domingo Matos) at CFBR (French Committee for Dams

and Reservoirs) it was announced that the installation of the

geomembrane has definitely almost stopped the reaction.

In masonry dams, the waterproofing system is similar to

the one adopted on concrete dams; the roughness of the

masonry generally requires installing a thick anti-puncture

geotextile under the geocomposite, and regularising with

mortar the surface where the perimeter seals are placed.

Kadamparai dam, owned by the Tamil Nadu Electricity

Board (TNEB), is an example. The dam is 67 m high and

478 m long, was completed in 1983, and is used as a forebay

reservoir to the 400 MW Kadamparai pumped-storage

scheme. From around 1995, seepage gradually began to

increase. Main seepage sources were deteriorated joints

between the stones of the masonry, cavities that had formed

in the masonry, joints between monoliths, and seepage

through the foundation rock. Over time seepage rates

increased dramatically, with a peak seepage of 38,000 l/min.

Since the conventional methods already adopted had failed

Fig. 12 Pracana buttress dam, Portugal 1992. The upstream face during rehabilitation and refurbishment works: from left to right, the new

intake, the black geonet covering the face, and the PVC geocomposite installed over the geonet. At right, the tensioning profiles


123

at Kadamparai, the final decision was to adopt an upstream

geomembrane; an international tender was floated, and the

waterproofing works started at site on January 17 2005.

The Carpi system at Kadamparai consists of an imper-

meable PVC geocomposite liner, mechanically fastened to

the dam body, tensioned and drained, according to the

patented solution with tensioning profiles. To mitigate the

roughness of the masonry, a 2000 g/m2 needle-punched

nonwoven anti-puncture geotextile was placed over the

masonry. The waterproofing liner is the same geocom-

posite installed at Pracana. As at Pracana, adjoining sheets

were vertically joined by heat welding. A double

mechanical seal at bottom, and separate drainage com-

partments for various areas of the upstream face and for the

area between the two bottom seals, provide accurate

monitoring of the efficiency of the system, implemented by

piezometers detecting if water is standing behind the geo-

composite, and by an optical fibre cable system that allows

locating the area of a leak if any (Fig. 14).

The whole system covering more than 17,300 m2

including the monitoring system was completed in

4 months, 6 weeks ahead of schedule. Total seepage has

been reduced from 38,000 l/m to about 100 l/m. It is more

than 10 years now still the measured leakage rate stands

around 100 l/m.

Rehabilitation in this type of dams is generally made on

the entire upstream face, but partial sealing systems have

been used to seal specific joints at heel or cut off wall

(Kolnbrein 200 m high arch dam and Schlegeis 131 m high

arch dam, both in Austria), or joints with failed joint sea-

lant (Vale do Rossim, Portugal). In recent times rehabili-

tation limited to most leaking areas, to meet budget

constraints or to stage construction according to available

funding, is also experienced.

Among the various design and installation aspects

addressed, the possibility of reducing uplift with a drained

system, and recent developments allowing underwater

repair of the entire upstream face.

Fig. 13 At left waterproofing works completed at Pracana dam. At right, the dam pictured in 2003, when the owner reports: ‘‘waterproofing may

be assumed to contribute for the reduction of the swelling process’’

Fig. 14 Kadamparai masonry dam, India 2005, pumped storage. The

installation of[17,000 m2 geomembrane system involved the use of

thick geotextile to cover the rough masonry face. Prior to installation,

the dam was leaking more than 38,000 l/m, after Carpi completed the

geomembrane installation leakage dropped to 100 l/m


123

Chapter 6: RCC dams

Extensive construction of RCC dams started at the begin-

ning of the 1980s. The use of geomembranes in RCC dams

followed closely, in 1984. Since 2000, the use of

geomembranes has been extended from new construction

also to rehabilitation of RCC dams (entire face, leaking

sections, cracks, holes). Rehabilitation has been carried out

also underwater and is described in ‘‘Chapter 7: special

cases’’.

In RCC dams, geomembranes are used to waterproof the

entire upstream face, or as external waterstop for contrac-

tion joints or repair of cracks. Basically all dams have been

waterproofed with one of two available options: exposed

geomembrane or covered geomembrane, both patented.

The exposed system is an evolution of the system used

for rehabilitation, and it was first adopted at Riou France, in

1990. Outstanding examples reported in Bulletin 135 were

Miel I (Colombia 2002), at 188 m then the highest RCC

dam in the world, and Olivenhain, 97 m high,

1,036,736 m3, and highest RCC dam in USA, 2003.

Miel I is a straight gravity dam constructed in a narrow

gorge in Colombia. To meet contractual schedule, the

original design of an upstream face made of slip formed

reinforced concrete was changed to a drained exposed PVC

geomembrane system, placed on a 0.4 m thick zone of

grout enriched vibrated RCC. This double water shield was

considered necessary due to the height of the dam. The use

of grout enriched RCC allowed good compaction at the

dam face, assuring a good finishing of the upstream con-

crete surface.

The waterproofing liner is a geocomposite, consisting of

a PVC geomembrane laminated to a 500 g/m2 non-woven

polypropylene geotextile. In the lowest part of the dam,

from elevation 268 m to elevation 330 m, the PVC

geomembrane is 3 mm thick, from elevation 330 m to

elevation 450 m it is 2.5 mm thick. The entire upstream

face is 31,500 m2.

The geocomposite face anchorage is made by parallel

vertical tensioning profiles, placed at 3.70 m spacing.

Where the water head is higher, i.e. from elevation 268 to

358 m, the stainless steel profiles have a central rein-

forcement. The configuration was slightly different from

the one shown in Fig. 12 because, according to the state-of-

the-art at the beginning of the 2000s, the U-shaped com-

ponent of the tensioning profile assembly was attached to

the formwork and embedded in the 0.3 m high RCC lifts,

while in current projects this component is placed after the

RCC is completed, like in rehabilitation of concrete dams.

The second component of the tensioning profile assembly,

placed over the installed PVC geocomposite and connected

to the first component, secures and tensions the PVC liner

on the upstream face. The profiles are then waterproofed

with PVC cover strips, as shown at right in Fig. 15.

The integrated face drainage system behind the geo-

composite consists of the gap between the liner and the

dam face, of the geotextile laminated to the PVC

geomembrane, of the vertical conduits formed by the ten-

sioning profiles, of a peripheral collector embedded in the

RCC, of the transverse discharge pipes discharging into the

gallery, and of ventilation pipes assuring water flow at

ambient pressure. The drainage system is divided into 4

horizontal sections (compartments), each discharging in the

gallery located at its lower point. Each horizontal com-

partment is in turn divided into vertical compartments with

separate discharge. In total there are 45 separate compart-

ments that allow accurate monitoring of the behaviour of

the waterproofing system.

Construction of the grouting plinth was made following

placement of the RCC. A PVC geocomposite, placed over

the completed RCC lifts and over the natural excavation

rock, waterproofs the plinth. The liner waterproofing the

Fig. 15 Miel I RCC dam. Left: U-shaped profiles and drainage

collector attached to the formworks are embedded in the RCC.

Middle: U-shaped profiles after embedment appear as vertical

drainage grooves in the face of the dam. Right: tensioning profiles

are waterproofed with PVC cover strips


123

plinth is watertight connected to the liner waterproofing the

upstream face by a tie-down seal. This type of seal, tested

at 2.4 MPa, is placed also at crest, to resist water

overtopping.

In correspondence of the contraction joints, two layers

of sacrificial geocomposite provide support to the liner on

the joint. The PVC geocomposite was installed in 6 hori-

zontal sections. A movable railing system was used to

install the PVC waterproofing system concurrent and

independent of RCC activities. The railing system was

attached to the dam face at first at approximately 90 m

above foundation, and then moved to some 140 m above

foundation. The travelling platforms, from which all

activities were carried out, were suspended at the railing

system. Installation of the PVC geocomposite could thus be

carried out from the platforms while RCC placement was

ongoing above the railing system. Staged installation

allowed early impounding while the dam was still under

construction (Fig. 16).

Construction of the dam started in April 2000 and ended

in June 2002, in total 26 months. The change in design

allowed meeting the schedule, and saving several 10 mil-

lions US dollars, because of reduced content of cement,

faster completion, earlier power generation.

Olivenhain RCC dam in California is a conventional

gravity dam 788 m long and 97 m high. The dam, the

highest RCC dam in USA and first RCC dam built in the

highly seismic state of California, is a key element of the

Emergency Storage Project (ESP) of the San Diego County

Water Authority, owner of the dam. About 90% of water is

brought to San Diego from hundreds of miles away, and the

aqueducts cross several large active faults, including the

San Andreas Fault. The ESP will provide water to the San

Diego region in case of an interruption in water delivery

deriving from an earthquake or drought.

Evaluation of the alternatives for the upstream face,

considering the magnitude of design earthquake and the

critical function of the dam to provide water during an

emergency, placed emphasis on seismic stability and

seepage control. In a range of 1–3, these features were

assigned the maximum weighting factor of 3 (Kline et al.

[4]). Special consideration was also given to construction

sequence because the dam had to be fully operational

within a certain date.

In the stability analysis, the exposed geomembrane liner

and its face drainage system were considered two features

that would tend to reduce the uplift pressure. Furthermore,

if this uplift reduction features were to be damaged and

rendered inoperable during a large earthquake which would

damage the geomembrane, the effects of uplift pressures

would not be as critical, because it would take some time

for the pore pressure to increase, and by then the water

level would have been lowered according to the rules of the

California Division of Safety of Dams. The external

geomembrane system received the highest score among the

11 considered alternatives.

Shaping blocks and plinth are waterproofed with the

same geocomposite used for the upstream face, watertight

connected to the geocomposite of the upstream face with

the same seal used at Miel I. Also the face drainage system

is similar to the one adopted at Miel I, with the addition of

a drainage geonet installed on the RCC (Fig. 17 on left), to

enhance discharge capabilities should accidental damage

occur to the impervious geomembrane. Under the pressure

of the hydrostatic load the geonet will maintain high

transmissivity, no water will be able to migrate through lift

joints in the body of the dam, thus saturation levels and

pore pressures in the dam will be lowered, with beneficial

effects on the stability safety factors, and on the appearance

at the downstream face.

The PVC geocomposite, the same adopted in the higher

part of Miel I dam, is fastened by vertical tensioning pro-

files at 3.70 m spacing. The embedded profiles have been

designed larger than standard, to create larger vertical

Fig. 16 Left: installing the geocomposite in horizontal phases

concurrent with RCC placement reduced times for completion at

Miel I. Right: the geocomposite already installed in the lower sections

allowed impounding the reservoir and testing the machinery while

construction was still ongoing


123

conduits and further enhance drainage transmission.

Stainless steel plates, 60 9 6 mm, placed every 40 cm

inside the profiles, avoid that the profiles deform under the

hydrostatic load. Each line of profiles discharges separately

into the gallery, and can be individually monitored. The-

oretically there is one compartment for each line, in prac-

tice since the area of influence of the vertical lines is not

watertight confined, some water of pertinence of one line

may still travel to the adjacent lines. The upstream face

has, therefore, been divided into 12 compartments, sepa-

rated by a vertical watertight seal, to allow defining the

area of the leak in case of damage.

The peripheral seals are made by compressing the

geocomposite with 80 9 8 mm flat stainless steel batten

strips. The seal is of the same type adopted at Miel I.

Waterproofing works were completed in 5 months. The

reservoir started filling on August 7, 2003. Concerning

resistance to seismic events: Olivenhain on June 16, 2004,

experienced a magnitude 5.2 earthquake, with reservoir

almost at full supply level. The event was centred about

60 miles SW of the dam site. Inspection was performed,

seepage rates were compared to those of the previous

inspection of June 1, 2004, and seepage was found to be

about the same, or smaller (Fig. 18).

RCC dams lined with PVC geomembranes typically

show insignificant seepage as compared to RCC dams

with conventional concrete facing. At Miel I, total leakage

at fully impounded reservoir is 2.0 l/s, mostly from abut-

ments [5]; Balambano 95 m high RCC dam, Indonesia,

exposed PVC system installed in 1999, has a total water

flow for all 6 box drains of the 15,490 m2 upstream face

varying from 0.012 l/s to a maximum of 0.965 l/s at full

supply level.

The covered PVC system was developed in USA, and

the first installation was made in 1984. The bulletin anal-

yses pros and cons of the two solutions, and critical aspects

of design and of installation techniques.

Chapter 7: special cases

Special applications are basically related to an external

waterstop system that can be installed since construction

(on contraction joints of RCC dams, or to allow partial

application at crucial locations). The system can also be

used to rehabilitate failing joints and cracks in concrete

facings (CFRDs, concrete and RCC dams), in the dry and

underwater.

Fig. 17 Olivenhain RCC dam, USA 2003. At left, drainage geonet is placed on the RCC to enhance drainage collection and discharge; at middle,

the PVC geocomposite is placed over the geonet; at right, the tensioning profile is connected to the profile embedded in the RCC

Fig. 18 The exposed PVC geocomposite system completed at Olivenhain RCC dam, USA 2003. At right, in 2004 Olivenhain, 97 m high,

sustained a magnitude 5.2 earthquake


123

The external waterstop system shown in Fig. 19, which

is patented, consists of:

• A support layer, installed over the completed RCC lifts,

which impedes the waterproofing liner from intruding

in the active joint at maximum opening of the joint

under the maximum water head. This component is

generally composed of one or more independent layers,

in function of the water head and anticipated move-

ments of the joints

• The waterproofing liner, a PVC geocomposite water-

tight anchored along the perimeter.

With[230% tri-dimensional elongation at break of the

PVC geomembrane, the external waterstop is more efficient

than a conventional embedded waterstop, elongation is free

over a larger width, bridging movements in the order of

several cm. Installation does not interfere with RCC place-

ment. Examples of new construction are Platanovryssi RCC

dam, Greece 1998, at 95 m the highest RCC dam in Europe,

and Porce II 118 m high RCC dam, Colombia 2000.

An outstanding example of special application is the

installation of a PVC geomembrane on the horizontal joint

between phase 1 and phase 2 face slabs at Karahnjukar

198 m high CFRD, where the same PVC geomembrane

had been installed on the toe wall in 2005. The PVC

geomembrane has the objective of waterproofing the hor-

izontal joint in case of potential cracking (Fig. 20).

Examples of repair are Dona Francisca RCC dam (63 m

high, Brazil, 2000, failing joints and cracks), Platanovryssi

RCC dam (the same system installed on contraction joints

during construction was used in 2002 to repair underwater

a crack) and Strawberry CFRD (50 m high, USA, failing

joints). In the last few years, the same system has been

adopted for underwater repair of cracks and failing joints in

concrete and RCC dams.

Chapters 8 and 9: quality control and guidanceon technical contents of contracts

Chapter 8 includes recommendations on Quality Control

and Quality Assurance at manufacturing, transport, and

installation. It discusses items to be addressed, type and

frequency of controls, and testing procedures.

Chapter 9 on technical contents of contracts provides

some guidelines on how procurement of geomembrane

Fig. 19 Scheme and example of external PVC waterstop installed during construction: Porce II RCC dam, Colombia 2000, 118 m high

Fig. 20 Example of special application: Karahnjukar, Iceland. In 2005 PVC geomembrane to waterproof the toe wall (left), in 2006 PVC

geomembrane to waterproof the horizontal joint of the 198 m high CFRD in case of potential cracking


123

systems for dams shall be done. It recommends requiring

previous experience of the material and of the designer and

installer in similar applications. It suggests that the owner

develops the design or at least the guidelines for the design,

to assure that the outcome of the waterproofing project is in

line with the expectations and respectful of the criteria of

safety, durability, capital investment and cost of mainte-

nance. Providing a detailed design and fixed requirements,

the owner holds responsibility of the design, but has full

control of it. Providing only guidelines, the owner transfers

responsibility of design on the tenderer, but the design is

not under his control and there is no certainty that it will be

approved by the authorities.

Appendixes

Appendix 1 consists of the database of dams on which

geomembrane systems have been implemented. The con-

tent of this database is not in the Bulletin due to the size of

the data. The version submitted to ICOLD was ‘‘frozen’’ at

31 December 2006 and lists 264 dams; from the trans-

mission to ICOLD, the number of dams with geomem-

branes has kept expanding, and the latest updating of

September 2014 listed 316 dams. This relates exclusively

to dams for which technical forms are available, but there

are many other dams that to the knowledge of the authors

incorporate a geomembrane.

Appendix 2 contains a list of terms and technical defi-

nitions concerning geomembranes, as produced by IGS, the

International Geosynthetics Society.

Appendix 3 contains the main references of the testing

standards on the use of geomembranes and implementation

of various dams.

Conclusions

Geomembrane systems have reached a high degree of

sophistication and reliability, and are recognised as a long-

term waterproofing method, when adequately designed and

installed. The satisfaction on the technical and economic

efficiency of the installed systems, as expressed by the

owners, is very high.

The height of lined dams has dramatically increased

over the years. Successful dam projects using geomem-

branes show that there is no theoretical limit for any type of

dam: at present, geomembranes have been installed on

embankment dams up to 198 m high (Karahnjukar, Iceland

2005), on gravity dams up to 174 m high (Alpe Gera, Italy

1993/1994), on new RCC dams up to 188 m high (Miel 1,

Colombia 2002), on tailings dams up to 230 m (when

completed, Las Bambas, Peru, ongoing). Performance after

decades of service shows that the very low permeability of

geomembranes is maintained over time, and that

geomembranes left exposed on the upstream face are able

to resist very aggressive environments (UV rays, ice,

waves, impact of debris, etc.).

In 2016 it is estimated that there are at least 400 large

dams in the world lined with geomembranes, mainly made

of PVC and mainly exposed. Underwater installation of

geomembranes in dams has become a kind of routine, and

has opened the way to systems that allow installation in

hydraulic tunnels with up to 900 m of head, and under-

water placement in canals without stopping the water flow.

The new Water Saving Basins of the Panama Canal

Expansion (2016) have been lined with an exposed PVC

geocomposite with an expected durability exceeding

100 years.

Acknowledgements Bulletin 135 was prepared by the European

Working Group, consisting of the following members: E. Aguiar

Gonzalez (Balsas de Tenerife, Spain), P. Bartek (Swiss National

Committee), M. Blanco Fernandez (Laboratorio Central De Estruc-

turas Y Materials C.D.E.X., Spain), P. Brezina (Povodi Odry, Czech

Republic), H. Brunold (Austrian National Committee), D. Cazzuffi

(ENEL CESI, Italy), H. Girard (Cemagref, France), M. Lefranc

(French National Committee), J. L. Machado do Vale (Portuguese

National Committee), C. Massaro (Azienda Energetica Metropolitana

Torino), J. Millmore (British National Committee), L. Schewe

(German National Committee), A. Scuero (Italian National Com-

mittee), P. Sembenelli (Italian National Committee), G. Vaschetti

(Italian National Committee), with the assistance of R. M. Koerner

(Drexel University/GSI, USA).

References

1. CIGB–ICOLD (1981) Use of thin geomembranes on fill dams.

Bulletin 38

2. CIGB–ICOLD (1991) Watertight geomembranes for dams. Bul-

letin 78

3. CIGB–ICOLD (2010) Geomembrane sealing systems for dams—

design principles and review of experience. Bulletin 135

4. Kline RA et al. (2002) Design of roller-compacted concrete

features for Olivenhain dam. Dams, innovations for sustainable

water resources. In: Proceedings, 22nd USSD conference, S.

Diego, USA

5. Liberal O et al. (2003) Ageing process and rehabilitation of

Pracana dam. In: Proceedings, ICOLD 21st International Congress,

Montreal, Canada


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Documents

Geomembrane sealing systems for dams: ICOLD … · TECHNICAL PAPER Geomembrane sealing systems for dams: ICOLD Bulletin 135 Alberto Scuero1 • Gabriella Vaschetti1 Received: 3 May