How to install fence 200mm offset from retaining wall?

Hi,

We are building our retaining wall that is 200m offset from boundary as per approved DA. I’ve been thinking of ways on how the fence can be installed at the boundary.

My engineering design for the retaining wall specifies gravel up to -200mm from the top of the wall. The rest will be plugged by soil. From my understanding, fence post will be concrete piered to a suitable depth for support.

I am worried that these fence piers will compromise my drainage for the wall (gravel, geofabric and ag line). It might puncture the geofabric, concrete the gravel, soil gets to the ag line, etc. Is there any other way to do this? I haven’t found sleeper post brackets that are 200mm offset.

Thanks in advance.