The report covers the initial phases of investigation into the use of underground methods of water disposal employed in the Waikerie Irrigation Area. The detailed geology of the area was established from surface exposures and by means of several stratigraphic boreholes. Later, more intensive drilling was carried out to delineate areas of Pleistocene clay believed to be responsible for poor sub-surface drainage in some areas. Changes in the groundwater regime resulting from the drainage underground of large volumes of water were established by means of a network of observation boreholes. Drainage and/or pump testing was carried out at 10 locations and in some cases attempts were made to improve the capacity of boreholes by acidising.