Melbourne's Pink Lake

Sitting directly below the Westgate Bridge, Westgate Park is a pleasant stretch of undulating grassland wedged between Port Melbourne and Fisherman's Bend, a short walk form the city.

The site has an interesting history.

In the 1930s it was owned by the Federal Government, and was home to the Department of Aircraft Production. The extensive facilities were used to design and build new aircraft designs, which were then tested on the site's own runway.

An aerial photo of the Westgate runway.

But the development of jet aircraft after World War II meant the runway became inadequate, and the department was moved to a larger property near Lara.

The vacant site was then used for a variety of public and private activities, including; motor racing, sand mining and waste disposal. The nature of these activities had a negative impact on the land, which became environmentally degraded.

The park under construction.

In the 1980s, the State Government decided to clean up the site, and set aside 54 hectares as a public park. It was opened in 1984, and dedicated as part of Victoria's 150th anniversary celebrations.

And the park is a welcome addition to a largely industrial part of the city. It sports a number of gentle walks, is home to a variety of bird life and even has a pedestrian punt, that crosses the Yarra on the weekends.

It also has three man made lakes, one of which turns bright pink in the summer time.

The striking colour is caused by a simple, but still quite rare, chemical reaction.

This is the park's salt water lake (the other major one is filled with fresh water) and the higher temperatures in summer cause some of the lake's water to evaporate, increasing the salt concentration. This then reacts with a single cell alga that exists in the lake, which produces the red pigment.

This interaction is only found in a small number of lakes around the world.