The northern tourist town has a hidden lake without which Broome would struggle to survive.
Broome may seem to be something of a miracle: a lush oasis surviving between the desert and the ocean. With the Water Corporation expanding Broome’s water infrastructure, it highlights the elusiveness of how this town by the bay, with no lakes or rivers, survives in the hot and harsh climate of North Western Australia.
The secret is under the ground. The Broome sandstone outcrops along the coastline and is famously imprinted by the feet of the biggest dinosaurs known to have walked the Earth. But it’s where this ubiquitous layer of rock is hidden below the pindan scrub away from the coast that it serves a much more utilitarian service. Being porous and open to soaking downpours, the Broome sandstone acts like a massive underground rain tank. Each year, five gigalitres (that’s 5,000,000,000 litres!) are pumped out of bores sunk into the Broome aquifer to water the gardens, run the showers, fill the pools, quench industry; and people even drink a tiny amount.
An unconfined aquifer is like a secret lake. There’s a vast water body out there that grows with the rain and falls when we take from it. Hidden from view, it can be a bit harder to get a feel for this impressive water body. But like any surface water, Broome’s little know water source is able to be polluted. A 2001 Water and River’s Commission report describes Broome’s water supply as vulnerable to industrial contamination. Fuel from tanks and other industrial chemicals can make their way into the water if there is a leak or spill at the surface. The report identifies plans to eventually move the town’s airport to a site partially within the existing water reserve as “a potential source of significant groundwater contamination…”.
Drilling through the relatively shallow Broome aquifer into deeper confined reservoirs of saltwater or oil also poses a contamination risk. The level of this risk is one of the major contentious points of the international fracking issue.
The Broome aquifer makes the town of Broome possible. Large amounts of clean drinking water in a region that receives an average of just 600 millimetres a year is almost miraculous. That it naturally contains some of the dissolved fluoride needed to keep local teeth shining is nothing short of extraordinary. But there are limits to this font of life.
The Water Corporation have begun works to increase Broome’s water supply. Three new bores will be added to the bore field, and new water storage and pipelines are underway to keep water flowing to the ever-growing town. The Department of Water estimates that the Broome bore field could provide up to 10.6 gigalitres without destabilising the saline interface. This is where the fresh water held in the Broome sandstone under land meets the salt water within Broome sandstone under the sea. The risk is that if you take too much freshwater out of the aquifer, then the saltwater will be drawn under the land.
Controversy around the oil and gas industry in the Broome area has driven a focus on the amount of water used by industry. Woodside Petroleum have been investigating using the Broome aquifer as a water source for construction of a gas processing precinct they are considering building 60 kilometres north of Broome. During construction, up to 6 million litres will be used every day. Woodside says that approval to take this water from the Broome aquifer will only be granted by the Department of Water if it is deemed sustainable. The company says a temporary desalination plant will be used if they can’t use the aquifer.
During operation of the proposed facility, 5 million litres of water will be needed each day or 1.8 gigalitres each year. This is more than all the water currently used by industry in Broome. A Woodside factsheet on the issues says “It is anticipated that operational water requirements will be met by a permanent desalination facility, powered by electricity generated from natural gas and use water drawn from the ocean.”
Concerned residents have also asked questions about the supply of water to the resources industry via the Port of Broome. In 2010 water was barged out of Broome to supply the resources industries on Barrow Island. A desalination plant now supplies this need. But included in the Water Corporation’s current Broome upgrades is the replacement of the main pipeline supplying the Broome port.
The CEO of the Broome Port Authority, Captain Vic Justice acknowledges that there is expected to be increased demand for water “…over the next few years in line with offshore resource industry development.”
But there’s a long way to go before the water supplied to industry via the Broome port is a big part of the overall use. Of the five gigalitres currently used in Broome, 1.3 gigalitres of this is by industry and commercial consumption. Of these 1.3 gigalitres, the Broome Port Authority reports that the most they’ve provided to industry since 2008 is 58 megalitres in 2010/11. That is under four percent of the water used by industry in Broome.
Even when Broome grows to the point that it uses the full 10.6 gigalitres calculated to be the sustainable extractable volume from the current bore field, predicted to happen around 2035, it’s not the limit of the entire aquifer. While the Water Corporation encourages conservative water use as there is a cost to providing water and the associated energy consumption, there is potential to open new bore fields further north. It would seem that if Broome can avoid damaging its aquifer, water won’t be the limiting factor in the size of the town blessed with an oasis in the hot dry north.