Hydrogeological report on water well monitoring in Aboriginal lands to May 2002

Abstract

Water well monitoring data from wells on Aboriginal lands (Pitjantjatjara, Yalata, Nepabunna and Oak Valley) are summarised for the period April 2001 to May 2002. This report also shows plots and analysis of all data for each well since monitoring began. In the Pitjantjatjara lands aquifers at all communities except Kalka, Mimili and Fregon showed significant recharge and water levels have recovered to, or are above, the levels recorded at the time of drilling. The three exceptions are probably extensive aquifers that have generally been free from signs of depletion. The only community for which there is any short term (5-10 years) concern is Indulkana. Whilst there was recharge to the older wells, the community now relies on the Indulkana Range wells for a larger portion of its water supply. The aquifer in which these wells is completed was not recharged and water levels are declining. At Nepabunna supplies are still marginal and the heavy pumping regime has made monitoring insensitive to small but possibly significant changes. Modification of the monitoring is required, preferably with separate monitoring wells. The Yalata aquifer is unaffected by pumping, but the groundwater level appears to be declining by natural drainage. No recharge is observed. Oak Valley supplies have held up remarkably well, but are still regarded as fragile. Stringent water management is essential if the additional costs of importing water are to be avoided.