Geomembranes, either on their own or in conjunction with an intermediate geosynthetic, can greatly increase the effectiveness of a canal lining system. A geosynthetic-lined canal prevents earth erosion, vegetation growth and provides improved flow rates and considerably less seepage. Geomembranes provide economical and technically superior canal linings, particularly where active, heaving soils may damage conventional concrete. Flexible lining systems can accept substantial movement without damage.

Geomembranes are well suited, not only for new construction, but also for lining over existing dysfunctional earthen or concrete lined canals that may be leaking or are cracked. Sub-soil drains can be installed below the geomembrane to manage advective leakage or subsoil water. Failed sections of concrete canals may be repaired with geomembranes.