The most important prerequisite of linings for controlling seepage losses from irrigation canals is their watertightness. In addition to being watertight, a lining must be relatively durable if it is to be economical. Rigid materials provide satisfactory linings for canals with well-drained and stable subgrades. Under other conditions, where expansive soils are encountered and ground water is a problem, a rigid lining such as concrete is not durable. Considering the many factors that govern the utility and durability of linings, the ideal lining would consist of a material with some flexibility, a material resistant to erosion and mechanical damage, and one with a smooth surface. The search for a material of this type led to a consideration of asphalt and rubber-coated materials. Natural rubber, while watertight, deteriorates rapidly. Some of the synthetic rubbers such as butyl, on the contrary, show high resistance to deterioration from weathering and biological activity.
Lauritzen, C. W. and Peterson, W. H., "Bulletin No. 363 - Butyl Fabrics as Canal Lining Materials" (1953). UAES Bulletins. Paper 320.