Does anyone have experience with water wicking on a larger scale? I am thinking of raised beds, 30' long by 4' wide (3' high) for each bed. 1' of water would be almost 900 gallons of water. That will leave 1.5' for the soil and supporting floor. Wicking would be done by cotton rope or old shirts fed down through PVC tubes to the water.
For ease of use, they would be 4' wide, but for efficient use of building materials they could be any width (18' in my case). In either case, the soil floor would be fully supported for the weight.
I am considering this method for the self watering aspect, but also for the issue of hard water clogging up irrigation lines/holes. This method would use underground feeder lines going into each bed, with either a sight tube to check level, or float switches to control a solenoid water valve for automatic level control. With the feed line placed at the bottom of an end wall, the water can be drained out before freezing sets in each year.