I think the key to working this out would be extending current practices employed for large buildings with an eye to interconnection. Maybe the best strategy w

I think the key to working this out would be extending current practices employed for large buildings with an eye to interconnection. Maybe the best strategy would be to modularize the arcology so that it would be composed of many interconnected structures that are each more or less self sufficient. You could apply this to the Old Man River City by designing it as individual slices of a toroidal pie and then replicating this design until you have the full shape.