Alright kiddo, so the Goldfields Water Supply Scheme is basically a really big system that brings water to a bunch of people who live in Western Australia. It's kind of like a super long straw that goes all the way from a place called Perth to a bunch of towns and cities in the eastern part of the state.
The reason they needed to make this system is because that part of the state is super dry, so there isn't a lot of water there naturally. But people still need water to drink and use for stuff like washing and growing plants, so they had to figure out a way to get it there.
So a long time ago, some really smart people decided that they would build a big canal to bring water from Perth to the Goldfields area. But that was a really hard thing to do, because the land is really rocky and there are a lot of hills and valleys to cross.
So they came up with a different plan: they built a huge pipeline instead! It's like a really long tube that goes all the way from Perth to the Goldfields towns, and it carries water inside of it.
The pipeline is really big and strong, and it's made out of a material called steel. It's buried underground for most of the way, so it's safe from things like animals and bad weather.
Nowadays, the Goldfields Water Supply Scheme is really important, because it helps a lot of people in those towns and cities get the water they need to live. And they're always working on making it better and more efficient, so that even more people can benefit from it in the future!