Précontraint 1215 seals Europe’s highest mountain storage reservoir at Alpe d’Huez!

  • Chantier de la retenue d'altitude de l'Herpie
  • Mise en oeuvre de la géomembrane Précontraint 1215 sur le géocomposite drainant
  • Mise en oeuvre de la géomembrane Précontraint 1215 sur le géocomposite drainant
  • Assemblage par soudure à air chaud de la géomembrane Précontraint 1215

Project data

• Client: SATA
• Consulting engineer: Alpes Ingé
• Earthworks Contractor: Socco

  • • Waterproofing Group: N.M.G. Étanchéité - main contractor and Polen’
    • Serge Ferrari composite material: Précontraint 1215 geomembrane

  • The Serge Ferrari Group invites you to an outstanding construction project at an altitude of 3000 metres: installation of 32,500 m² of Précontraint 1215 composite membrane at the heart of the Herpie high-altitude storage reservoir, the highest in Europe! This gigantic artificial lake with a capacity of 165,000 m3 will be used to supply water for artificial snow production and coverage of the famous Sarenne ski run (Europe’s longest) in the Alpe d’Huez skiing area.

    An outstanding construction project

    “The Sarenne ski run – with its exceptional length and gradient – is unique but is a victim of its own success! As records over the last 15 years or so show, snow falls have been reducing and making the situation a little critical in terms of the snow cover expected by lovers of nature and real thrills” declares Christian Reverbel, SATA’s (Société d’Aménagement Touristique de l’Alpe d’Huez et des Grandes Rousses) ski run manager for Alpe d’Huez.
    The idea of the Herpie high-altitude storage reservoir goes back a decade! This was therefore a well thought out, long-term process involving conservation of the entire ski run length and gradient, while maintaining the full unity of this project comprising 3 distinct yet complementary components:

    • The artificial lake
    • A technical building
    • A pipe network installed over the entire length of the ski run.

    “We will spray water for 10 hours every night, based on the knowledge that a snow canon consumes 40 to 50 m3 of water/hour, and we will have 72 snow canons positioned to cover 70% of the ski run area. We therefore borrow this water and crystallise it during a winter to give pleasure to skiing and snowboarding lovers, before returning it to the natural system from which it came by either melting or evaporation at the end of each spring” explains the Alpe d’Huez ski run manager.
    “This lake integrates perfectly into the surrounding environment. It is the outcome of 11 years of studies, during which we performed specific inventories of not only the flora and fauna, but also the fish stocks in the lower part of the ski run. The ski run was developed in partnership with ecologists and full re-vegetation will be performed throughout the development coverage. Our aim is to meet artificial snow production requirements in an environmentally reasonable and reasoned manner” concludes Christian Reverbel.

    Why was Précontraint 1215 selected?

    The strength of this 100% recyclable Serge Ferrari geomembrane guarantees the installation’s absolute watertightness. Its breaking strength is 550 daN/5cm compared with conventional geomembranes only offer approximately 100 daN. Its capacity for absorbing high-altitude temperature variations and constraints, such as avalanches, stone falls, etc., is optimal.
    The specific nature of its formulation ensures high tolerance under extreme temperatures and temperature variations, which can range from -50 °C to +50 °C.
    Other advantages: Its dimensional stability, flexibility and resistance to UV radiation (comparable with Saharan levels at 2,500 – 3,000 metres).

    Geomembrane transport and installation

    61 rolls (200 lm each) of Précontraint 1215 composite membrane were deposited on site by helicopter.
    Roll width assembly by hot air welding was performed on site by contracting group N.M.G. Etanchéité and Polen’. “This project is very unusual in terms of its size since storage reservoir capacity is conventionally 70 – 100,000 m3. In this case, the 165,000 m3 obviously create greater constraints – in particular structural – even though we are in favourable geological conditions. We have rock in virtually the entire site area, which guarantees natural ground stability” explains Franck Machet, Alpes Ingé’s geotechnical and environmental design manager.
    “This project therefore doesn’t raise any specific problems, but rock blasting always represents a delicate stage”. Concerning Herpie, this operation enabled us to build the downstream embankment, to produce the materials used for reservoir bottom drainage and the fine materials used to cover its internal slopes prior to laying the Serge Ferrari geomembrane” explained Franck Machet.
    Waterproofing system

    • A drainage geocomposite specifically designed and laid beneath the Précontraint geomembrane to ensure its protection allows all minor water infiltrations from the reservoir slopes to be collected
    • The 1.25 mm thick Précontraint 1215 geomembrane ensures watertightness
    • A soil retaining geocomposite guarantees stability of confinement material (30 cm of stone) protecting the Serge Ferrari geomembrane.

    The reservoir water intake is located on the Sarenne mountain stream. Water is only extracted when the glacier snow, which supplies the mountain stream, is melting between May and July.


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    Serge Ferrari range for the industry & the environment

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    Essentials represent Serge Ferrari’s traditional mid-range of quality materials developed since the company was founded in partnership with textile solution makers and installers.
    Their Précontraint technological qualities ensure these classic materials meet functional demand for technical performance and make Serge Ferrari a reference on its many markets.

    Specialities are product ranges that meet the standards, usages and required specific performance characteristics of certain professional sectors: agriculture, building, communities, industry, safety, etc. To accompany professionals in their day-to-day operations, Serge Ferrari offers a range of specific accessories: pre-cut strips, cord for boltropes, Silcord, adhesive, bobbin trolleys, etc.

    Manufacturing expertise

    The exclusive advantages of Précontraint technology

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    • a woven base cloth of high tenacity polyester threads,
    • a coating with the membrane under constant tension in both the warp and weft directions throughout the entire manufacturing process
    • a high performance polymer surface layer with a constant and greater thickness over the top of the yarns,
    • a dirt-resistance surface treatment.
    • un traitement de surface anti-salissure

    Controlled dimensional stability
    Précontraint Serge Ferrari technology guarantees the material’s exceptional dimensional stability, which is almost identical in warp and weft directions. Deformation resistance in the weft direction exceeds that of conventional coated fabrics. This exclusive advantage is very important during textile tensioning.


    Précontraint Serge Ferrari composite materials offer high resistance to stretching due to their very low absorbency.

    In addition, due to the dual advantage exceptional stability and straight threads, Précontraint Serge Ferrari composite materials stretch three times less with the weft than conventional coated fabrics.


    Longation in the weft direction under a 200 daN/m load over a period of 100 hours.
    Then residual elongation without load.

    Totally controlled uniformity
    The bi-axial tension central to Précontraint Serge Ferrari technology ensures rigorous control of weft threads and absolute running thread compliance throughout all production batches.


    Précontraint Serge Ferrari® membranes ensure total compliance along the thread, (identical throughout all production batches).

    The weft threads of conventional coated fabrics deform significantly and variably depending on the production batches.




    Enhanced durability
    Material lightness during handling is an important criteria in facilitating making up and installation. Précontraint Serge Ferrari technology ensures this lightness, whilst guaranteeing a thicker coating layer at the top of the yarns. The polyester base cloth is therefore better protected against climatic conditions.




    Thicker coating on the thread crests ensures that the physical properties of Précontraint Serge Ferrari membranes are preserved over time – a key factor in the durability of your projects.

    Manufacturing expertise

    Swiss made expertise

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    swiss-madeSerge Ferrari’s Swiss production unit expertise is long-time recognised in the field of speciality products requiring “Swiss Made” top-of-the range quality, innovation and technology.

    A multi-technical and multi-material approach

    Serge Ferrari AG masters all the coating techniques :

    • direct,
    • by cylinder,
    • by transfer,
    • foam...

    and has experience in different types of base cloth:

    • non-woven fabrics,
    • woven fabrics,
    • knitted,
    • glass material...

    Original specialities

    • Environmentally-friendly membranes: the benchmark in a fi eld where the quality and compliance with standards is irreproachable.
    • Silicone membranes: an innovation, the fi rst applications of which concern textile architecture but also marine applications, a field in which Serge Ferrari textiles are increasingly successful.
    • Transfer coating: a technology that enables the group to develop a full range of synthetic leather designed for commercial furniture applications.
    • Infrared: expertise in anti-radar and protection techniques for security fabrics.
    • Repositionable adhesive fabrics: a technology developed for the digital printing market.

    Environment & agriculture


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    High-performance High Tech membranes




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