Three crisscrossing threads run through Giroud's engineering work corresponding to the capacities of designer, innovator and performance investigator. Traveling in the world or with google maps, we may come across traces of the designer: a dam and a water reservoir in France, a landfill (closed now) in Delaware, USA, a canal in New Zealand.

About 30km west of Saint-Tropez, France, the 17-meter high Valcros Dam [1, 2] was constructed in 1970. The dam was designed entirely by Giroud, who was assisted by colleagues as needed. The design included site investigation, material selection, dam geometry, geotextile filter design, drainage system design, dam slope stability, upstream slope protection using stones on geotextile, and design details. For the first time, a geotextile was used as filter to replace (not readily available) sand in the downstream slope, and a geotextile was used in a dam to protect the upstream slope [3]. For these distinctions, Valcros Dam was on the cover of the Civil Engineering Magazine of ASCE in January 1989. Six years after construction, its performance (aging, downstream drainage function and upstream protection) was evaluated and found to be satisfactory for all buried geotextiles [3]. Testing was repeated with samples obtained 21 years after construction and similar results were obtained [4]. The dam is still in service today (2025).

About 8km south of Grenoble, France, the 10m-deep Pont-de-Claix water reservoir [5,6] was constructed in 1974. It is built on a terrace between two steep slopes, 50m above a chemical plant for which it serves as an emergency water supply. After conducting soil investigation and evaluating slope stability, which indicated the sensitivity of the steep slope to a massive leak from the reservoir, Giroud prescribed and tested a double liner system, the first with two geomembranes above and below the gravel leakage detection layer. The reservoir has been monitored by the plant personnel since the end of construction. Thirty years later a small amount of water was collected through the leakage removal pipes; the leak was found and repaired underwater [7]. During a site visit forty years after construction, the exposed part of butyl rubber geomembrane was found to be in good condition [7] or [8+9]. Fifty years later, the reservoir and the liner system are still in service.

The 17-hectare (approximately 295m by 580m) municipal waste landfill in Sussex County, Delaware, USA, received waste in its two cells between 1984 and 1997 and was covered by an exposed geomembrane constructed in 1997-1998 [10]. The exposed geomembrane cover system consisted of a 0.15 m grading soil layer underlying a 0.9mm reinforced polypropylene geomembrane. Designing against wind uplift, a significant risk facing exposed geomembranes, was made possible by recent at the time developments by Giroud and coworkers, as described in the “Researcher” Section. The exposed geomembrane cover system was conceived as a demonstration project and permitted as a long-term intermediate cover, with the requirement to conduct every ten years performance evaluations including geomembrane testing of samples. A few years after the first positive evaluation, the owner elected to replace the initial 0.9mm green reinforced polypropylene geomembrane with a 1.1mm off-white geomembrane of the same type and install sacrificial patches to minimize disturbance during sampling. In March 2024, a third positive evaluation recommended the continuation of the project for the next demonstration period [11].

At the foothills in central New Zealand, 23.5-km long Tekapo Canal connects two hydroelectric power stations, close to lakes Pukaki and Tekapo, transferring flows from the tailrace of one power station to the headpond of the other. The 35-m wide and 7-m deep canal was originally unlined. In 2013-2014, critical sections were lined with geomembrane [12]. The role of Giroud in this design included: site visits, evaluation of stresses in different types of geomembranes in case of seismic activity, geomembrane selection, evaluation of geomembrane liner stability considering the relatively high water velocity in the canal, design of geomembrane ballasting and anchorage to ensure geomembrane stability [13].

Lastly, by Lake Erie in the United States, an extraordinary structure, non visible to any traveler or google map surfer: a 20-m deep underground water reservoir built in 1981 to contain extra pure water for a Proton Decay Experiment mentioned in The New York Times [14]. The reservoir was excavated in a salt formation to be in a non-radioactive environment, and at a depth of 600 m to be protected from cosmic radiation [15]. As we will see later, it was not the first time Giroud had to deal with a reservoir foundation material that could be eroded by a leak. It is the first entirely geosynthetic double liner system with two geomembranes and a geonet leak detection system [16].

Apart from novel conceptual designs and uses of geosynthetic materials, Giroud’s innovations include procedures as well. In 1983, he prepared the first guide for the construction of geomembrane liners [17]. In 1983-1984, with Joe Fluet and Ray Steinle, and later Dan Schauer, of Geosyntec, he established a team of technicians providing construction quality assurance for geomembranes and other geosynthetics used in waste disposal landfills by leading waste management companies in the US [18].

An account of Giroud as engineer would be grossly incomplete without a sample from his involvement in more than seventy performance investigations, which gave opportunities for developing innovative rehabilitation concepts or new analytical techniques, and also distilling lessons learned in published case histories. He started soon after obtaining his civil engineering degree in 1961, when a major sheet-piling failure occurred in 1963, during the construction of the foundations of a 100 m tall high-rise building in Grenoble, France. Giroud was one of the three members of the team of experts appointed to determine the causes of the failure.

The failure of Tancarville water reservoir in Normandie, France, in 1972, was due to leakage eroding away soil over a large karstic cavity, resulting in bursting of the geomembrane liner over the cavity [5, 6, 15]. The karstic limestone underlying the few meters of soil had not been factored in the initial design. After the failure, Giroud conducted a site investigation and recommended the use of a double liner. The double liner was implemented as follows (in the order of construction): bituminous concrete secondary liner, leakage detection layer made of gravel stabilized with bitumen, and butyl rubber geomembrane primary liner. This is the first double liner, the concept of which was presented in a lecture in Paris on March 13, 1973 [19].

Another case of adverse interaction of reservoir fluid – underlying soil, in Jordan: a geomembrane-lined reservoir of phosphoric acid (2 hectares, 6 m deep) on a soil with a high calcium carbonate content [6, 15]. Leaking acid through holes in the geomembrane attacked the calcium carbonate, thereby causing the formation of cavities in the soil supporting the geomembrane liner. The reservoir suddenly emptied in 1983, eleven months after the first filling, when the geomembrane liner burst over one of the cavities. As part of his investigation, Giroud showed that the pressure due to the depth of acid over the geomembrane and the diameter of the cavity were consistent with the geomembrane tension-strain curve. He prepared the conceptual design of the rehabilitation of the site, which consisted in replacing the existing reservoir by three reservoirs: a double lined storage reservoir and two single-lined evaporation ponds, as explained in Figure 12 of [6].

In 1988, a pioneering full-scale test of a textured geomembrane was conducted by Giroud on the sloping cover of the New Milford Landfill [20]. The field test and related laboratory tests were commissioned by a waste management company in the US prior to using textured geomembranes, then newly introduced on the market. Both the field and the laboratory tests showed the essential role of a nonwoven geotextile bonded to a geonet to ensure high interface shear strength with a textured geomembrane.

Finally a performance investigation that led to the development of an analytical description of geomembrane cracking pattern. During a very cold night of 1989, an exposed geomembrane liner in an empty water reservoir of a power plant in Utah developed extensive cracking [21]. Giroud and his colleague Ian Peggs were asked to investigate this failure. While Peggs conducted testing, Giroud developed a set of equations that reproduced the crack pattern, thereby demonstrating the failure mechanism [22, 23]. In particular, Giroud showed that the observed crack pattern was initiated by strain concentration inherent to the geomembrane seam geometry [22]. This finding was important because it indicated that the geomembrane failure was not due to a defective design or installation. Also, this finding initiated research on strain concentration generated due to seam geometry described in the “Researcher” Section and mentioned in the “Communicator” Section. For the rehabilitation of the liner system, Giroud and Peggs developed a system of compensation panels to alleviate tensile stresses in the geomembrane [21].

Valcros Dam (1970)

[1] Giroud, J.P., 2010, “Development of criteria for geotextiles and granular filters”, Prestigious Lecture, Proceedings of the 9th International Conference on Geosynthetics, Guarujá, Brazil, May 2010, Vol. 1, pp. 45-64, https://library.geosyntheticssociety.org/proceedings/prestigious-lecture-development-of-criteria-for-geotextile-and-granular-filters-pdf/

[2] Giroud, J.P. & Gross, B.A., 1993, “Geotextile Filters for Downstream Drain and Upstream Slope, Valcros Dam, France”, In: Geosynthetics Case Histories, Raymond, G.P. & Giroud, J.P., Eds., ISSMFE, pp. 2-3. [link]

[3] Giroud, J.P., Gourc, J.P., Bally, P. & Delmas, P., 1977, “Comportement d'un textile non tisse dans un barrage en terre”, Proceedings of the International Conference on the Use of Fabrics in Geotechnics, Session 6, Paris, April 1977, pp. 213-218. (in French)

[4] Delmas, P., Farkouh, B., Faure, Y. & Nancey, A., 1994, “Long term behaviour of a geotextile as a filter in a 24 year old dam: Valcros”, Proc. 5th Int. Conf. on Geotextiles Geomembranes and related products, Singapore, pp. 1199-1202, https://library.geosyntheticssociety.org/proceedings/long-term-behaviour-of-a-geotextile-as-a-filter-in-a-24-year-old-earth-dam-valcros/

Pont-de-Claix Reservoir (1974)

[5] Giroud, J.P., 2016, “Leakage Control using Geomembrane Liners”, The Victor de Mello Lecture [Presentation slides]

[6] Giroud, J.P., 2017, “Design and Performance of Reservoirs Lined with Geomembranes”, The Széchy Memorial Lecture [Paper]

[7] Giroud, J.P. & Gourc, J.P., 2014, “The first double geomembrane liner forty years later”, Proceedings of the 10th International Conference on Geosynthetics, Berlin, 8 p.

[8] Giroud, J.P. & Gourc, J.P., 2015a, “The first double geomembrane liner forty years later – Part 1”, Geosynthetics Magazine, Vol. 33, No. 1, February-March 2015, pp. 14-22. [link]

[9] Giroud, J.P. & Gourc, J.P., 2015b, “The first double geomembrane liner forty years later – Part 2”, Geosynthetics Magazine, Vol. 33, No. 2, April-May 2015, pp. 20-26. [link]

Delaware Landfill Closure (1997-1998)

[10] Gleason, M.H., Germain, A.M., Vasuki, N.C., & Giroud, J.P., 1999, “Design and Construction of an Exposed Geomembrane Cover for a Solid Waste Landfill”, Proceedings of the 7th International Landfill Symposium, Sardinia, Italy, October 4-8, Vol. 3, pp. 335-342.

[11] Geosyntec Consultants, 2024, “Report on Evaluation of Exposed Geomembrane Cover System at Cells 1 and 2, Southern Solid Waste Management Center Jones Crossroads, Sussex County, Delaware” March 2024.

Tekapo Canal (2013-2014)

[12] Scuero, A., Vaschetti, G., Cowland, J., Eldridge, J.J. & Giroud, J.P., 2022, “Un canal étanché par géomembrane PVC: le canal de Tekapo en Nouvelle-Zélande”, 13èmes Rencontres Géosynthétiques, Saint-Malo, France, 9 p. (in French)

[13] Giroud, J.P., Jacka, N., Dann, C. & Eldridge, J., 2013, “Hydropower canal geomembrane liner analytical techniques”, Proceedings of The Conference on Multiple Uses of Dams and Reservoirs, NZSOLD/ANCOLD, Rotorua, New Zealand, 12 p.

Proton Decay Experiment (1981)

[14] Sullivan, W. 1979, Physicists to Test Theory on Atom’s Slow Decay Test in Lake Erie Mine, The New York Times, Dec. 17, https://www.nytimes.com/1979/12/17/archives/physicists-to-test-theory-on-atoms-slow-decay-test-in-lake-erie.html

[15] Giroud, J.P., 2019, “Lessons learned from case histories of reservoirs lined with geomembranes”, Revue Française de Géotechnique, Vol. 159, No. 2, 13 p., https://doi.org/10.1051/geotech/2019014

[16] Giroud, J.P. & Stone, J.L., 1984, “Design of Geomembrane Liner for the Proton Decay Experiment”, Proceedings of the International Conference on Geomembranes, Vol. 2, Denver, CO, USA, June 1984, pp. 469-474. [link]

Geomembrane Quality Assurance (1983)

[17] Giroud, J.P. & Kastman, K.H., 1983, “Guide Specifications for Construction of Flexible Membrane Liners for Hazardous Waste Disposal Facilities”, 32 p. published as part of Assessment of Technology for Constructing and Installing Cover and Bottom Liner Systems for Hazardous Waste Facilities”, by Ghassemi, M., Metzger, J., Powers, M., Quinlivan, S., Scinto, L. and White, H., EPA 68-02-3174, May 1983.

[18] Giroud, J.P. & Fluet, J.E., Jr., 1986, “Quality Assurance of Geosynthetic Lining Systems”, Geotextiles and Geomembranes, Vol. 3, No. 4, Elsevier, London, England, pp. 249-287, https://doi.org/10.1016/0266-1144(86)90026-9

Tancarville Reservoir Rehabilitation (1972)

[5, 6, 15]

[19] Giroud, J.P., 1973, “L'étanchéité des retenues d'eau par feuilles déroulées”, Annales de l'ITBTP, 312, TP 161, Décembre 1973, pp. 94-112. (in French)

Phosphoric Acid Reservoir Rehabilitation, Jordan (1983)

[6, 15]

New Milford Landfill Test (1988)

[20] Giroud, J.P., Swan, R.H., Jr., Richer, P.J., & Spooner, P.R., 1990, “Geosynthetic Landfill Cap: Laboratory and Field Tests, Design and Construction”, Proceedings of the Fourth International Conference on Geotextiles, Geomembranes and Related Products, Vol. 2, The Hague, The Netherlands, May 1990, pp. 493-498.

Utah Powerplant Reservoir (1989)

[21] Giroud, J.P., 2005, “Quantification of geosynthetic behavior”, Geosynthetics International, Vol. 12, No. 1, pp. 2-27, https://doi.org/10.1680/gein.2005.12.1.2

[22] Giroud, J.P., 1994a, “The Mechanics of Geomembrane Stress Cracking”, Computer Methods and Advances in Geomechanics, Siriwardane, H.J. & Zaman, M.M., Editors, Balkema, Proceedings of the Eighth International Conference on Computer Methods and Advances in Geomechanics, held in Morgantown, WV, USA, May 1994, Vol. 1, pp. 177-188.

[23] Giroud, J.P., 1994b, “Determination of Geomembrane Shattering Cracks”, Geosynthetics International, Vol. 1, No. 2, pp. 149-180, https://doi.org/10.1680/gein.1.0007