Potable (over 1000 mg/l) groundwater occurs in 5 lenses. Annual yield totals 14 000 to 19 000 ML. Between 400 and 2 500 ML / year (seasonally dependent) is abstracted for reticulation. Diffuse, unquantified extraction for stock and domestic purposes accounts for the balance of groundwater usage. Constraints to the present and future management practices and data collection and processing requirements are identified.