ABSTRACT
Water reforms in Australia recognise the environment as a legitimate user of a groundwater resource. This presented a challenge for scientists to determine the environmental dependency on groundwater from a Tertiary basalt aquifer in northern New South Wales (NSW) as part of an aquifer management plan. The Alstonville Plateau fractured rock basalt aquifer is characterised by a high degree of surface water connectivity and a shallow dynamic watertable. Three fundamental types of groundwater dependent ecosystems (GDEs) were recognised as existing on the plateau, being (1) groundwater-fed wetlands such as seepages and springs; (2) riparian and aquatic ecosystems (including the hyporheic zone) within or adjacent to streams fed by groundwater baseflow and (3) terrestrial vegetation communities that have seasonal groundwater dependency, such as rainforest remnants that access the shallow groundwater. Hydrogeological assessment of the basalt aquifer was combined with detailed mapping of springs and seepages and associated floral and faunal dependencies. This GDE mapping was incorporated into the gazetted water sharing plan for the aquifer (DLWC, 2003) and formed the basis for management rules defined for buffer zones around high-priority ecosystems.
