pervious materials meaning in Hindi

Examples

1. For example , after the collapse of ditong dam in idaho , may 5 , 1976 , it was found that it was not impervious very well , the impervious curtain was built poorly . when the seepage went through the impervious curtain , the exit water from the pervious material of the downstream or the right side of dam through the foundation or certain line between the foundation and the dam caused contact scour and piping