Rottnest Island - Forbes Ridge

Between 12 and 14 January 1942, the 22 Australian Army Field Company began excavating Forbes Ridge, along with sites at Bickley and near Oliver’s Battery. These works were undertaken to establish reliable water storage across Rottnest Island at a time when fresh water was scarce and held significant strategic importance.

 

Each location was designed to accommodate 46 “squatter” water tanks, a low-profile style of galvanised steel tank commonly used in Australia during the early to mid-20th century, including throughout World War II. Rather than being tall and narrow, squatter tanks were wide and low in height, allowing them to sit directly on the ground or on a simple compacted base. This made them stable in high winds, easy to install and well suited to exposed or remote locations such as Rottnest Island.

 

Each tank had an individual capacity of 7,000 litres, giving a total storage capacity of 322,000 litres per site. Tanks of this type were typically supplied in sections, transported flat and assembled on site. Their low profile also reduced visual prominence, an advantage in a defensive landscape.

 

On Rottnest Island, where there are no permanent freshwater sources, these tanks played an essential role. They were used to collect and store rainwater, often fed from nearby huts, sheds or other military structures via simple guttering. The stored water was used for everyday purposes including washing, cooking and drinking, supplying all troops stationed on the island (AWM2020.71.2725).

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The site was later marked on maps as Forbes Ridge Fresh Water Storage.

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AWM2020.71.2725 - 22 Field Company RAE - December 1941 to December 1942.