A study has been carried out to determine the cause of declining water levels in wells for irrigation, stock and domestic supplies. The study commenced in 19/1 and has involved field surveys, the establishment of a network of observation wells and the drilling of five exploration wells. It is concluded that the long term decline in the water table, noticed by local landowners since the turn of the century, is due to the change in land use from pasture to intensive lucerne production. Water levels in the observation wells show only seasonal fluctuations since 1971, and the long-term decline appears to have stopped. Groundwater pumped for irrigation forms a significant part of the water budget, but there is no direct evidence that irrigation abstraction is causing significant groundwater depletion in the area. No controls on the use of groundwater have been recommended at this stage, but monitoring of water levels will continue. Further largescale exploitation of groundwater by irrigation may alter the situation and controls may be necessary in the future.