Bitumen was ;n use 5000 ago for irrigation works that are still in good condition. Today, bituminous geomembranes are providing efficient, durable waterproof linings to irrigation canals, ponds and reservoirs throughout the world. A survey of twenty irrigation dams around 10m high built between 1973 and_ 1983 in France with unprotected geomembrane facings found them performing well after 10-20 years service. Linings to a reservoir at Goude! in Niger and canals cut in laterite near Niamey have demonstrated their suitability in tropical climates. In North Africa, the gulf states, Singapore, India and New Zealand, Sm-wide bituminous geomembranes have been in use on irrigation canals for some ten years and are still performing satisfactorily. In the USA, leaky areas on a large concrete-lined canal were stopped with an SBS bitumen-based geomembranes available in 4m widths in France