More recent attempts have focused on making a depression about 9” deep and about 9” wide. Those numbers were chosen as this would hold about 2 ½ gallons of water; enough for about 4 hours of irrigation with ½ gal emitter. Filling the depression largely with compost which is porous allows the water to descend to the bottom of the hole and fill from there. Various other amendments could be added for vine nutrition and water retention.