Collie River Valley Region and the Wellington Dam

As European setlement spread throughout WA in the 19th century, so did the demand for timber to build houses, shops and bridges, and to supply the rapidly expanding rail network with sleepers.

Jarrah was richly prized and became the first commercial export for the colony.
West Australian Jarrah was used to pave the streets of London.

Jarrah also proved ideal for construction and building work and it was used for bridges, railways, jetties, houses, furniture, underground mines and ships.
Jarrah and black-butt timber was cut for the buildings and formwork used during the construction of Wellington Dam.
Wellington Mills, just a few kilometres from where the dam would one day be built, was a timber settlement.
Steam trains carried timber and sleepers to the port of Bunbury.

Timber was a major export for Western Australia around the turn of the century.
However, soon after improved technology and a changing economic situation led to the demise of the big mill, which closed in 1919.
The Wellington Mills township and several smaller mills survived until 1950 when they were destroyed by fire.

However it wasn't long before more and more land was taken up for farms and agriculture.
The new settlers named the Collie River Valley region "Wellington", in honour of the Duke of Wellington.
The name was later adopted for the Wellington Dam and the once-thriving timber settlement of Wellington Mills.

Construction
Two dozen surveyors and construction workers made their way along the banks of the Collie River in 1931 searching for the best site to build a new dam.
After about three weeks they chose a site where the sides of the valley sloped down to a large, flat granite rock that formed the river bed.

Construction of the Wellington Dam began in November, 1931.
More than a hundred workers, many with their wives and children, made their way to live in the tiny settlement of tents pitched in a forest clearing.

The location was isolated deep within the forest and access was critical.
Penrith, small mill siding on the Brunswick to Collie railway, was upgraded to handle equipment and supplies to the dam.

The men working hard to establish a foundation on the river bed before the high annual winter flows.During the summer months the river flowed through two small channels.
By diverting the water through one channel the workers were able to dig a foundation and build the concrete wall in stages across the river.

The men laboured on the dam wall, in the rock quarry and at the sand pit nearby.
The base of the dam wall had to be excavated and formwork built to hold the concrete.
Other workers were busy clearing the valley where the water would gather, building an access road to the site, and digging irrigation channels further downstream.

An area on the northern slope was chosen as the best site for the construction plant.
A Babcock and Wilcox boiler, donated to the project by the Bunbury Town Council, provided steam power for the main engine room, concrete mixer and conveyor belts.
A Sentinel type air compressor supplied air for three forges, jackhammers and a shipping hammer.
Leads from the compressor were run more than 300 metres to the main works for excavation on the foundations, and 107 metres to the quarry for rock drilling.

The first rock crusher was always breaking down and production was poor.
In June 1932, when the crusher again broke down, it was decided to bring in a Jacques Jaw Crusher from Harvey, and output immediately doubled.

A conveyor belt carried the crushed stone into bins where it was mixed with sand cement.
The mix gravitated down chutes and into the concrete mixer.

The concrete was poured from a chute suspended on an overhead cable between two giant steel towers that where constructed on each side of the valley.
Chutes slung between the towers carried concrete to timber formwork that shaped large sections of the wall.
The concrete was poured in blocks 15 metres long by 7 metres wide and 2 metres deep.
Every few days the pouring chute was moved along to as a new section.
It was difficult and tedious operation for the men.

The wall was made up of two straight, 76-metre "wings" that stretched from each side of the valley, joined by an 80-metre curved section in the middle.
By diverting the river through two natural channels, the wall was gradually extended across the granite rock base that formed the river bed.
Most of the wall was built in this way with the final concrete sections poured from a wooden trestle framework.
The dam wall was finished in just two years.

At the time the main dam wall was being built, more construction work was going on downstream.
A road was cut through the bush to a site 11 kilometres away where a small diversion dam was built to raise the water level to feed into the main irrigation channels.

The project was a major success, and soon after the dam was finished in 1933, the demand for water was more than could be supplied.
The amount of water available to irrigation was increased in 1944 when another metre was onto the height of the main dam wall.
In 1955 work commenced to treble the storage capacity of the dam, by raising the wall another 15 metres.
Completed in 1960, this increased storage provided enough drinking water, carried by pipe, for the inland towns of the Great Southern.
The dam, as it is today, is 34 metres high and 366 metres long.
The dam stores about 186 million kilolitres of water when full.