ABSTRACT
The classic problems of large-scale irrigation projects are those presented by rising water-tables and soil salinity—problems created by disturbances of the natural hydrological balance.
Development of shallow water-tables and soil salinity and means of controlling or minimizing their ill effects are discussed generally and in relation to the Australian landscape, particularly that of the riverine plain of southeastern Australia where major irrigation development has so far been concentrated.
The peculiar features of the Australian landscape—resulting from comparative lack of recent orogenic activity—are responsible for the peculiar character of the Australian irrigation scene, as compared with the rest of the world, and peculiar methods of control of soil salinity without general (subsurface) drainage.
The conclusion is advanced that the potential for further major project development lies in schemes of a similar character in similar situations—low intensity irrigation without general drainage, on areas of flood-plain deposition in semi-arid regions. The importance of high quality irrigation water— another peculiar feature of the Australian landscape—and especially of rain in the control of soil salinity under shallow, saline water-table conditions is emphasized: under arid conditions drainage is essential.
Water-table and salinity problems are to a large degree disabilities of scale; to this degree isolated small or individual irrigation projects are free of them.
