Ferrar, H.T. 1929 The soils of irrigation areas in Otago Central. Wellington: Government Printer. New Zealand Geological Survey bulletin 33 42 p.
Abstract: Otago Central is a popular name applied to an indefinite area of the drier inland portions of Otago. It is situated near the middle of the southern and broadest portion of the South Island, and on the eastern side of the mountain divide in about 45 degrees south latitude. This inland region is characterized by steep-sided ranges separated by chains of intermontane depressions. It is one of the driest parts of New Zealand, having a mean annual rainfall of less than 20 in. The irrigation areas are situated on the intermontane basins and on the lower slopes of the mountain-ranges. The purpose of the soil survey of irrigation areas in Otago Central is to supply maps that indicate how irrigation water can best be distributed over the land, or removed if drainage is necessary, and at the same time supply information with regard to the special problems arising from irrigation. This survey is not a final investigation. It does not show what areas will best repay irrigation and what quantities of water will be required. It is known that such great quantities of water percolate into beds of gravel as to render stretches of land unsuitable for irrigation, but these cannot be recognized until water is led on to them. Since water-supply has a preponderating influence on production in Otago Central, the soil maps seek to portray the distribution of land differentiated according to irrigation and drainage facilities. (auth/DG)