Q: We are trying to design and construct an aquiclude with a geosynthetic clay liner (GCL). Do you have any experience with this application where a GCL has been used as the impervious barrier between a flowing stream and the underlain geologic formation?
A: I have not heard of a GCL being used alone in this application. I have heard of a geomembrane-GCL-GM sandwich being used in such a case. It was over a relatively small area, about 8 acres (3.2 ha), in Maryland near the Pennsylvania border just off I-95. Maryland Department of Transportation used it to assist with problems from artesian water near an on-ramp with shallow foundations with success.