Lessons learned from case histories of reservoirs lined with geomembranes

Three case histories (in Europe, the Middle East and North America) are used to address some important aspects of the design and performance of geomembrane-lined reservoirs constructed on, or in, soil and rock. After a brief introduction to geomembranes and related geosynthetics, a first case history presents the failure of the liner of a reservoir located on karstic ground. The following lesson was learned: a defective construction detail, combined with an inadequate design (due in part to ignorance of the geological and geotechnical conditions), can cause a catastrophic failure. This case history led to the development of the double liner concept. The second case history is about a double liner. It illustrates the important role played by the mechanical properties of the geomembrane. Geotechnical engineers, who are accustomed to deal with complex materials such as soils and rocks, are well prepared to understand the properties of geomembranes. A third case history shows that a “zero-leakage guarantee” offered by irresponsible suppliers of geomembranes, and believed by uninformed owners and engineers, can lead to a catastrophic failure. This case history illustrates the importance of a design that addresses the potential consequences of leakage through liners. The conclusion of this paper is that only a rigorous engineering approach, including both geotechnical and geosynthetics aspects, can ensure the successful performance of geomembrane-lined reservoirs and other liquid containment structures such as dams and canals. Examples presented at the end of the paper show that large reservoirs, canals and dams have been successfully constructed with a geomembrane liner as the sole waterproof component.