I thought I might seek the wisdom of those of you who know about land drainage.
I have a groundwater problem in the driveway and had a French drain leading from the problem area into a pipe inserted into the wall of an inspection chamber within the garden. Well, although there was a steady trickle of water through the pipe into the chamber, there were still significant damp patches in the drive.
I investigated last week and found the level of the perforated pipe under the drive is about 200mm below the discharge level into the inspection chamber. Water is therefore running uphill, presumably by a combination of capillary action and (resultant?) raising of the water table.
I'm wondering how the drainage guy might explain this situation, especially as the money he charged could have got me a new Blaser. (Not that I would, of course...)