Harris River Dam

Statement of Significance

Harris River Dam, Harris River Road, Collie, an earth and concrete structure constructed in 1990, has cultural heritage significance as an alternative to Wellington Dam as a potable water source via the Great Southern Towns Water Supply Scheme.

Physical Description

The Harris Dam was constructed in 1990. Construction materials and description is described above, as per The EPA report.

History

Located on the Harris River, north of the Collie townsite, the Harris Dam has a catchment area of about 325 square kilometres

Prior to construction of the Harris Dam, the Wellington Reservoir supplied potable water supply to the Great Southern Towns Water Supply, the Collie District and the Swan Coastal Plain. It was expected that salinity levels would rise such that the water could no longer be used as drinking water.

After consideration of a number of options, including reforestation of the Wellington catchment, the Water Authority of WA determined that the construction of a dam on the Harris River ‘to be the most effective option which would provide adequate high quality water to the GSTWS in the short term, and have the least environmental impact’.

The EPA report describes the project (p5-6):

The dam would involve the construction of the following components:
• Main dam embankment
• Spillway
• Intake tower
• Outlet culvert
• Pump station and raising main
• Public viewing areas, recreation facilities and amenities.

The embankment would be of homogenous earth fill obtained from local sources, protected with a rip rap layer of rockfill material. Foundation stripping would remove organic material, and deep excavation of the river bed would be necessary to remove alluvium.

The spillway would be an open lined concrete chute founded on rock excavation, and have the capacity to pass all floods up to the Probable Maximum Flood (PMF) level. A terminal structure and Stirling basin would be located where the spillway flows re-enter the river.

The intake tower would consist of a reinforced concrete stem and a sheet steel clad hoist house, with access from the embankment via a bridge. The tower would have multiple intake posts to enable water to be dawn over a range of water levels. A concrete outlet culvert, housing two 900mm nominal diameter pipelines would extend from the intake tower to a pump station located immediately downstream of the embankment. Construction will be carried out early in the development programme so that the culvert could divert river flows.

A rising main would be constructed from the pump station to link with the GSTWS pipeline from Wellington Dam approximately 3km east of Collie Pumping Station. The power supply to the pump station is expected to be via a power line from the existing SECWA grid, and is proposed to be located adjacent to the main access road, Tallanalla Road.

Other permanent facilities would include sealed access roads linking all the major facilities, public vantage points (and associated parking facilities) and public recreation area downstream of the embankment. Site access would be gained via the relocated Tallanalla-Collie Road, which will facilitate heavy vehicle access to the site.

Earthfill material would be obtained from borrow pits within the reservoir area. Fine filter materials would be from a new sand pit located near Griffin. Coarse filter material, aggregate from concrete shelters and rip rap material would be obtained from established local quarries.

The Harris Dam was commissioned in 1990 and officially opened on 14 December by the Minister for Water, Mr Ernie Bridge, MLA.

The Harris Dam, with a supply capacity of up to 15 million kilolitres, supplies water to over 35 towns in the Great Southern via the Great Southern Towns Water Supply Scheme.

Integrity/Authenticity

High/ High

Condition

Good

Uses

Historic Themes

Creation Date

Publish place record online (inHerit):

Last Update

Disclaimer

This information is provided voluntarily as a public service. The information provided is made available in good faith and is derived from sources believed to be reliable and accurate. However, the information is provided solely on the basis that readers will be responsible for making their own assessment of the matters discussed herein and are advised to verify all relevant representations, statements and information.