The Tomago Sandbeds lie parallel to the coast between Newcastle and Port Stephens, beginning at Tomago and extending north-east for 25 kilometres to Lemon Tree Passage. Below the Sandbeds is an aquifer (or underground water source) consisting of clay and rock layer underneath fine sand. The sand is on average 20 metres deep, but reaches a depth of 50 metres in places.
Rain water lands directly on the sand surface to replenish the aquifer, with some of the water being lost to plants and evaporation. The water table is approximately 4.8 metres above sea level when full and 1.8 metres above sea level when empty.
Extraction of water from the aquifer
There is a network of more than 500 individual bores covering 100km2 from Lemon Tree Passage west to Tomago. After treatment at Grahamstown Water Treatment Plant, water from the western Tomago Sandbeds is piped to consumers in Newcastle and the lower Hunter regions.
To the east of Lemon Tree Passage, a smaller volume of water is extracted and treated by the Lemon Tree Passage Water Treatment Plant and piped to Karuah, Lemon Tree Passage and Tanilba Bay.
The importance of the Sandbeds to the supply system
The Sandbeds are strategically important for both ongoing and backup water supply. The ongoing supply from the sandbeds reduces the load on surface water sources and thereby allows greater overall yield from the total water supply system. The large storage volume can be used as a reserve supply during drought and is available as a backup supply in the event of water quality issues in the dams.
Water quality and catchment health
Water from the Tomago aquifer good quality. Sand itself is a good filter of contaminants and therefore pollutants do not travel quickly and are normally inactivated. In addition, most of land in the catchment areas is a protected area which preserves drinking water quality.
Hunter Water works with land use planners and industry in this area to protect the Sandbeds as a natural resource.