I have a customer who lives in a townhouse end unit. Hit back yard has about a 3' slope from left to right. He wants us to install a retaining wall between his property and his neighbors so that he can level is back yard and use it. I need a little help on how to do this properly with regards to re-enforcement. We have walys used geogrid on all of our walls but this requires us to dig anywhere from 3' to 6' behind the wall in order to install it. In this case we dont have that ability since that would mean diggin into the neighbors yard and tearing down the bushes she has installed along the property line. Since the yard is narrow to begin with, only 15' wide, by bringing the wall 3' in we essnetially eat up a good portion of the soon to be usable space. Is it possible, to secure the wall by another means?