Groundwater virtual tours video transcript

[Background music]

[Voice over]: Like most parts of the world, climate change has impacted our state and changed how we source water and supply drinking water in WA. 

We have a number of water sources available.

Rainfall runoff into dams and catchments, desalination, groundwater and groundwater replenishment.

Although it keeps a low profile, groundwater is a very important source, and is responsible for around 40% of Perth's total drinking water supply.

But like all water sources that rely on rainfall, it is under pressure due to climate change and therefore needs to be managed wisely.

What exactly is groundwater?

You'd be excused for thinking there are large underground lakes in giant caves that we stick a pipe into and pump the water from. 

Well, that's not 100% accurate.

Whilst there are large amounts of water down there, they aren't exactly rivers or lakes.

They're called aquifers. 

They are defined as an underground layer of permeable rock or sediment, like sand, sandstone or limestone that hold groundwater.

Try to imagine filling a bucket of sand with water.

As you add the water, it doesn't sit on top of the sand and overflow, but fills all the little spaces between the grains of sand.

That's all groundwater is. 

Some soil and rocks have big holes, like sand and limestone. 

They're easy to get groundwater from. 

And lucky for us, that is exactly the type of soil and rocks that Perth has.

To access it, we need to pump the water out of the ground.

We use bores.

These are similar to wells which are small deep holes in the ground.

Often a bit of pipe is used to keep the sand from collapsing it.

Our bores are a lot like the garden bores you might have seen around, but they are usually deeper and have bigger pumps.

We operate around 700 bores across the state. 

These bores range in depth from about 20m deep to 1000m deep. 

So how does the water get there in the first place? 

Groundwater comes from rain, which trickles through from the surface.

Along the way, the water might collect contaminants from people, animals, roads, and all the things that are on the surface of the ground.

These can be unhealthy for us, which is the main reason we treat the water before it becomes drinking water.

Over hundreds and thousands of years, water can trickle down very deep.

Deeper water doesn't have the contaminants from humans as they have been naturally filtered out.

But it does pick up salt and other minerals from the soil it travels through.

Before we drink the water, we often treat it to remove some of those minerals and fine particles and make it taste and look better, too.

There are several aquifers around Western Australia, the oldest and most reliable being the Yarragadee, which stretches from up near Geraldton right through to the south coast.

It is estimated some water has been in the Yarragadee for over 30,000 years.

From these aquifers, the groundwater is pumped into one of our groundwater treatment plants, like this one at Neerabup.

The groundwater enters the plant through these pipes before undergoing the water treatment process.

The process used to prepare the water for drinking depends on the water quality.

The water quality is determined by the depth, soil and location of the bore field where it is extracted from.

Question, do you think this groundwater will be warm or cold?

It's actually quite warm.

Usually around 24°C, but can be up to 55°C.

This is because it is coming from deep under the Earth's surface.

Neerabup Groundwater Treatment Plant is designed to remove three minerals from the water.

Calcium, which is also known as the hardness of the water, iron and manganese.

These contribute to the brown color of the water and can cause stains on everything they contact, like your clothes.

Neerabup Groundwater Treatment Plant was upgraded in 2022.

This was to increase the treatment capacity from 100 megalitres to 150 megalitres per day, which accommodates the increasing population living north of Perth. 

This is equivalent to 60 Olympic swimming pools.

Initially, the incoming water undergoes an aeration process which sprays the water high into the air. 

This puts oxygen into the water, releasing any trapped gases and helping remove or precipitate the iron from the water.

After aeration, the water goes through a process to soften the water.

Remember calcium, which I mentioned earlier?

Hard water is water with high mineral content.

It's formed when water moves through deposits of limestone like our aquifers, which are largely made up of calcium and magnesium carbonate.

If the water is too hard, it can cause scaling to occur in the pipes and limescale build up in appliances like kettles.

The water is softened using these crystallactors.

This process enables a chemical reaction to occur that takes the calcium or hardness out of the water, forming calcium carbonate pellets.

These pellets are recycled in farmland to help plants grow, as they contain a lot of natural minerals.

After the water has been softened, it’s passed through these dual media gravity filters.

Neerabup has 11 filters in total.

These filters use a layer of sand and a layer of anthracite to remove any minute particles before the water is then pumped into the clear water tank on site.

There are so many interesting elements that make our groundwater treatment plants function smoothly.

One of my favourites are these surge vessels.

They protect our plant and water network assets by acting like shock absorbers for any water that may surge or flow rapidly in one direction.

Finally, the water is treated to Water Corporation guidelines, which exceed the Australian Drinking Water Guidelines to ensure it is safe and ready to drink.

From here, we pump the water through our pipe network to our customers and into one of our reservoirs, where it is stored until someone turns on a tap.

Our team constantly monitor water quality inside and outside of the plant.

We are regulated by the Department of Water and Environmental Regulation, and comply with their direction of where and how much groundwater we are able to extract.

These decisions are based on a number of inputs that help us determine the most responsible and sustainable way to use groundwater to meet our ongoing needs.

We are looking for innovative and sustainable ways to replenish our groundwater.

This will ensure we have a strong water future in the face of climate change.

One way we are securing a sustainable water supply for the future is through groundwater replenishment.

This involves treating wastewater beyond drinking water standards and pumping the purified, recycled water into our underground aquifers, which store and naturally filter the water until we need it, thus recharging our groundwater supply.

It doesn't rely on rainfall and has the potential to recycle large volumes of water naturally and sustainably.

This program is well underway at our Craigie Advanced Water Recycling Plant, and makes up around 5% of Perth’s water supply.

We all have a role to play in being waterwise to shape WA’s water future.

Together, we all need to protect this very important resource that is groundwater.

Through reduced water use and efficient water processes.

To find out more about our water world,visit our website.