New Approaches for Allocation Reductions and Groundwater Salinity Management in South Australia

Abstract

The Tintinara area is located in the Upper South East of SA and lies 200 km southeast of the capital city of Adelaide. An unconfined Quaternary Limestone aquifer lies at a shallow depth (< 5 m), provides high well yields (< 200 L/sec) and is extensively used for the irrigation of lucerne (alfalfa). In 2003, the first management plan introduced licences, a volumetric entitlement and required metering of extractions. The size of each entitlement was determined by the theoretical crop irrigation requirements (TCR) for the existing area of the range of crops irrigated by a variety of systems (flood, sprinkler, drip). A review the management plan in 2008 found that metered extractions had been reasonably consistent at about 15,000 ML/yr which is only about half of the volume that had been allocated to irrigate the same area of land. This large gap between usage and allocation will make future management responses difficult and ineffective. After extensive consultation with the affected irrigators, an allocation reduction program was initiated that minimised impacts on existing users and would be staged over several years so that irrigators had time to adjust their operations. This program included a review of the TCRs using more recent information.