Leakage through Geosynthetic Dam Lining Systems

An experimental testing program was conducted to quantify leakage through a geomembrane liner system when subjected to high hydraulic heads. Leakage through geomembranes is mainly due to the presence of defects, which may occur during installation and operation. Previous studies focused on leakage through landfill liners (i.e., low hydraulic heads) have led to analytical models and simplified equations to estimate and predict the leakage rate through a geomembrane lining system. However, available methods used to estimate leakage are limited to a range of head that is experienced in landfills. The results of the experimental program presented herein are compared to available analytical models. A simplified equation was developed using an analytical model to predict leakage rates for a range of conditions representative of dams, including representative hydraulic heads and soil hydraulic conductivity of the soil. The new equation is compared with data from the experimental program and also with existing models. This paper discusses the advantages of using a geomembrane in tandem with a compacted clay liner as a redundant lining system for earth dams.