For more than 20 years the NSW government has monitored groundwater conditions at keys sites across the Blue Mountains to address increased urbanisation and demands on groundwater use close to sensitive environments. The Blue Mountains sandstone aquifers located approximately 50 kilometres from the city form a plateau that rises up to over 1,000 m above the coastal plain. There are small urban areas which surrounded by National Park that occurs along a major transport route linking Sydney to western New South Wales.
There are dominant spectacular cliffs, canyons and waterfalls made up of Triassic aged Narrabeen Group and Hawkesbury Sandstone geology and geomorphology. These make up a series of multiple porous rock aquifers at different levels. The sandstones cover an area of about 3,238 km² of which 2,375 km² is National Park, and are part of the broader Blue Mountains World Heritage Area. The shallow and intermediate aquifers are considered critical to spring flow and to stream baseflow in the upper plateau rivers. Groundwater has been shown to support hanging valley communities particularly in the upper Blue Mountains near Katoomba.
The NSW government manages groundwater across the state of NSW under the Water Management Act 2000 and the gazetted Water Sharing Plan for the Greater Metropolitan Region Groundwater Sources 2011. In support of this management monitoring has been progressively established using automatic groundwater level loggers and a substantial period of record has now been obtained. Hydrogeological investigations in the past have shown that complex multi-layered sandstone aquifers occur within the Blue Mountains Sandstone and there is a high degree of connectivity with surface water systems.
Examples of long term hydrographs and geological cross sections will be presented specific to differing aquifer characteristics. This information is being used to monitor and assist in managing groundwater extraction currently and into the future.