The layman term for What is a French drain? (grate) is manhole cover. Say "manhole cover" and pictures of spies/heros making use of the underground sewage system popping out of manhole cover in Hollywood films appear.Historically since that time Man invented the sewage system since the Roman Times to drain water and urban waste away for sanitation purposes, manhole covers (drain covers or grates as we prefer to call What is a French drain? ) have already been invented out of the basic need to prevent people from falling into underground sewage and also prevent large objects from entering the drains which cause choking which eventually could lead to flooding.Fast forward to the modern day, the sewage system is still utilised under all cities worldwide. As opposed to the crude stone manhole covers the Romans use in the ancient days, nowadays we have special steel reinforced stone gratings that serve the thousand year old function of covering the inlets of our sewage system.More than simply Healthy Smart Gardening Methods for Each Season. , check out Jonite's range of drain covers (drain gratings) here: http://www.jonite.us/products/creative-grates