Operating as a backup to Grahamstown Dam, Tomago Sandbeds can provide about 20 per cent of the Lower Hunter’s drinking water.
This underground water source runs parallel to the coast between Newcastle and Port Stephens, starting at Tomago and stretching north-east for 25 kilometres towards Lemon Tree Passage.
|Accessible aquifer volume||60,000ML|
|Areas supplied||Lower Hunter, up to approximately 20% of volume|
|Land use breakdown of catchment||44% State Conservation Area, 21% Hunter Water freehold, 21% industrial, 8% Defence (RAAF Base), 3% Bombing Range, 3% rural residential|
Our current storage levels
Our water levels drop faster than most other major Australian urban centres during hot, dry periods because we have shallow water storages and high evaporation rates.
Below Tomago 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.
Rainwater 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 is of a good quality. Sand itself is an efficient filter of contaminants and therefore pollutants do not travel quickly and are normally inactivated. In addition, most of the land within the catchments falls under protected areas, 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.
How it works
- An extensive system of underground bores and vacuum stations draws raw water from the sandbeds and pumps it to Grahamstown Water Treatment Plant.
- Once treated, 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 Tomago Sandbeds fall under Hunter Water owned land and the Tilligerry State Conservation Area (SCA), which is known as a ‘Special Area’ in the Hunter Water Act. The reserve is jointly managed by NSW National Parks and Wildlife Service and Hunter Water, and is closed to the public in order to protect groundwater quality and water extraction infrastructure.
The penalties for non-compliance and further information can be found on the Public access to dams and catchments page.