In this paper e propertfes comparison between the ooniposite-geoniembrane -and single geomembrarie–both having same thickness of impervious ieomembrane has been elucidated. Finaally, two engi-. neering cases of different embankments and dams with the· composite geomembraneas impervfous layer have been enumerated in ordef to expound those required engineering charactenstics and effectsof the composite geomembrane.