Embankment Dams - Granular Filters and Drains

The importance of filters and drains within the body of an earth, earth-rock, or rockfill dams must be uppermost in the mind of the embankment dam designer. Indeed, many incidents of failure or near failure can be attributed to the absence of filters and/or drains or to filter/drain protection which was not appropriate to the application. The literature within the various ICOLD Congress proceedings and other sources provides ample case histories of such incidents. Depending on the data cited, 30 to 50 percent of accidents to embankment dams have involved piping or inadequate drainage: the safety of embankment dams depends to a large degree on the proper design and construction of filter and filter/drain systems.

This bulletin is not meant to be a design manual but rather a summary of the current state of the practice.