Melbourne’s biggest sewage plant is also one of the best places to watch birds in Australia. Close to 300 species turn up there, and some of them fly in all the way from Siberia.

Back in the 1880s Melbourne had a problem it could no longer ignore. Open sewers drained into the Yarra River and Hobsons Bay, and cholera and typhoid moved through the city with grim regularity. A Royal Commission in 1888 looked at the mess and pointed to a fix that sounds crude now and was, in its way, bold then: send the sewage out of town and let the land handle it. The Melbourne and Metropolitan Board of Works began buying land at Werribee, west of the city, and in 1897 the Werribee Farm opened as Melbourne’s first sewage treatment plant.

The 1897 fix: why paddocks, and why Werribee

The choice of Werribee wasn’t random. The board wanted low rainfall and soils that would soak up a lot of water without turning to swamp, and the flat country west of the city fit the bill.

The early method was land filtration, which is exactly what it sounds like. Sewage flowed downhill along a big sewer to the farm, where the ground had been graded into paddocks and flooded on a repeating cycle, so the soil and grass could do the filtering. Cattle and sheep then grazed the pasture that came up afterward.

It used a lot of land to avoid using much technology, and for its era it worked. The city stopped tipping its waste straight into the river. That one decision, to spread the problem thinly across a huge flat expanse rather than pile it up in one place, is where everything else here traces back to.

How the plant works now

The old flooding method has largely gone. Today the sewage is cleaned in modern ponds rather than by flooding paddocks, but the sheer size of the place remains the headline. The site covers about 10,500 hectares, which Melbourne Water compares to Phillip Island. It takes in around half of everything Melbourne flushes and drains, usually put at roughly 500 megaliters a day.

A plant this large doesn’t just process water. It keeps a permanent, reliable network of shallow ponds, lagoons, and damp margins going across thousands of hectares. In a dry country, in a dry part of a dry state, that is rare and steady. The birds noticed long before most people did.

How a sewage farm became a great bird site

Many bird species have been recorded here. Melbourne Water’s own figure is more than 300 species. For a single site, that’s a large tally, and a good chunk of the birds arrive from a very long way off.

The standout is the red-necked stint, Australia’s smallest and most abundant migratory shorebird, a bird that weighs about as much as a few coins. Up to 8,000 of them turn up in September, having flown down from breeding grounds in north-eastern Siberia.

William Steele, a principal biodiversity scientist at Melbourne Water, put the trip plainly: “Some of the migratory species, like the red-necked stint, sharp-tailed sandpiper and curlew sandpiper, fly around 12,000 kilometres from their breeding grounds up in Siberia”.

What that bird needs at the end of such a flight isn’t a pretty view. It needs shallow water, exposed mud, and a steady supply of the tiny creatures that live in both. A large sewage plant, running year-round, delivers exactly that, in quantity, on a schedule. The stint isn’t putting up with the plant. It’s using it the way it would use an ideal natural estuary, and there aren’t many of those left intact along this coast.

The permit puzzle: a working plant that is also a protected wetland

The site was named a Ramsar-listed wetland of international importance in 1983. Ramsar is a global treaty that flags wetlands worth protecting. The result is a genuine oddity: a live piece of city infrastructure, also protected by an international treaty for its birds, run by the same organization, on the same ground, at the same time.

That double identity is why you can’t just wander in. You need a permit or a licensed guided tour, with a single-visit permit costing around $20. It’s a working plant, with the safety and disease-control concerns that come with that. Even so, Melbourne Water wants people to come when they can. Steele has said the migration is “quite remarkable and we encourage the public to take any opportunity to visit the site with birdwatching groups”. That’s the organization talking up its own site, but the enthusiasm is easy to understand once you know what turns up.

What we take from an accident that turned into habitat

The people who picked Werribee in the 1890s probably weren’t thinking about migratory shorebirds. They were thinking about typhoid, and about getting sewage out of the Yarra. The birdlife is a side effect, an accident of scale and water and steady management that no one set out to build.

We keep coming back to how often good habitat now sits inside working infrastructure rather than out in the wild. As natural wetlands along the coast have been drained and built over, a sewage plant has held on to the shallow water and mud that a tiny bird from Siberia needs to survive a flight across the world. Habitat doesn’t always look like wilderness. Some of the best of it turns up in the places we built to handle our own mess.