"Failure, caused by a variety of mechanisms, is common to drainage systems of all kinds. Leachate collection and cap drainage systems, which remove excess liquid from hazardous waste land disposal facilities, are no exception. Failure of these systems, however, may be a greater cause for concern than failure, for example, of agricultural drainage systems. This is especially true for leachate collection systems at hazardous waste disposal facilities. Undetected failures may cause leachate to build up on top of the liner. This can lead to failure of the liner system and contamination of groundwater. Furthermore, failures which are detected may be difficult to repair, and replacement is no longer a simple last resort since excavation of hazardous wastes would be required. Information is presented on those mechanisms which may cause leachate collection' and cap drainage systems failure. Furthermore, information on design, construction, inspection, and maintenance for these systems is presented in order to minimize the potential of failure. Techniques to repair a failed system are also described."