There are quite a few canalised streams in my area and I was watching one riparian owner's contractor rebuilding his stream retaining walls. The top 2 metres of these walls were being constructed in 225 (9") dense concrete blockwork, three leaves thick making a total wall thickness of 675 width of wall. Watching the work I said to the owner "Is there going to be any cross bonding between the leaves?" I didn't see any, nor did I see any ties being installed. Comments by budding Civil Engineers?