In 1970,use geotextile as a filter in a dam in Frence.
The dam has been in service ever since 1970,and the performance has been satisfactory till now,as follow,
1.Constant trickle of clean water
2.Flow rate consistent with the hydraulic conductivity of the embankment soil
3.No seepage of water ever observed through the downstream slope
4.Geotextile filter in good condition and clogging absolutely negligible (0.2% of the pore volume of the geotextile)