Geotextiles in Embankment Dams - Association of State Dam Safety ...

Chapter 1—Current Policy on the Use of Geotextiles in Embankment Damsare Federal agencies which have a regulatory role with respect to dam safety forfacilities that are privately owned and operated. These regulatory agencies includethe Corps of Engineers, Federal Energy Regulatory Commission, Office of SurfaceMining, and Mine Safety and Health Administration. The policies of a few of theseFederal agencies were investigated for this study as follows:1.2.1 Bureau of ReclamationThe Bureau of Reclamation (Reclamation) has constructed more than 600 dams andreservoirs in 17 western states. The current agency policy is that geotextiles can beused in embankment dams, but not as a sole element in a critical application. Forcritical applications there must be a redundant system that will protect the damshould the geotextile fail to perform its design function.The use of geotextiles in embankment dams is established by a written DesignStandard (Bureau of Reclamation, 1992). The document states “If a geotextile is tobe placed within an embankment where future access is extremely difficult, a backupsystem should be included in the design similar to conventional design methodswithout a geotextile. Thus if the geotextile failed to perform, the backup systemwould maintain the integrity of the dam while a permanent solution is sought.”1.2.2 Corps of EngineersThe Corps of Engineers began experimenting with use of geotextiles as filters belowerosion control materials in conjunction with Bob Barrett of Carthage Mills in thelate 1950’s. By the 1970’s, plastic filter cloth was being used extensively for erosioncontrol applications. In some cases, problems were encountered which resulted inrestrictions on use of these products. The current policy that has resulted from over40 years of experience is summarized in Table 1Table 1.1.—Corps of Engineers Policy Documents Related to Use of Geotextiles in DamsYear Reference Title Notes1984 ETL 1110-2-286 Use of GeotextilesUnder Riprap1986 EM 1110-2-1901 Seepage Analysis &Control for Dams,Appendix D - FilterDesignLessons learned from Tennessee-Tombigbee Waterway.Use in inaccessible areas must beconsidered carefully.Fabrics should not be used asfilters on upstream face or withinembankment.1992 EM 1110-2-1914 Relief Wells Well filters should consist of7