Canning Dam is a water supply dam located in the Darling Range, approximately 30 kilometres southeast of Perth, Western Australia. The dam impounds the Canning River and forms the Canning Reservoir, which provides a portion of the potable water supply for the Perth metropolitan area. It is owned and operated by the Water Corporation of Western Australia.
Location and Catchment
- Geographic setting: Situated near the locality of Pickering Brook in the Shire of Kalamunda.
- Catchment area: Approximately 133 km² of the Canning River catchment, comprising forested hills and tributary streams.
- Coordinates: 31°58′S 116°13′E (approximate).
History
- Naming: The dam is named after the Canning River, itself named in honour of British statesman George Canning.
- Construction: Work on the dam commenced in the late 1930s and was completed in 1940. The reservoir was first filled in 1942, providing an additional source of water for the expanding city of Perth.
- Upgrades: Since its initial construction, the dam has undergone periodic maintenance and safety upgrades, including spillway modifications and instrumentation enhancements. Specific dates and details of later upgrades are not comprehensively documented in publicly available sources.
Design and Structure
- Dam type: Earthfill embankment with a concrete gravity spillway.
- Dimensions: Approximately 44 m in height and 400 m in crest length.
- Spillway: Ungated overflow spillway designed to pass design flood events safely.
- Materials: Primarily locally sourced earth and rockfill, with concrete components for the spillway and outlet works.
Reservoir Characteristics
- Total storage capacity: About 4.9 gigalitres (GL) (≈ 4,900 ML).
- Surface area: Roughly 2.6 km² at full supply level.
- Maximum depth: Approximately 35 m near the dam wall.
Operation and Water Supply Role
- The reservoir is integrated into Perth’s broader water supply system, which includes other dams such as Mundaring Weir and Serpentine Dam.
- Water from Canning Reservoir is treated at the nearby Canning Dam Water Treatment Plant before distribution.
- The dam contributes to the overall reliability of water supply, particularly during periods of low rainfall.
Environmental and Recreational Aspects
- Canning Dam Regional Park: The surrounding catchment is designated as a regional park, offering protected forest, native flora and fauna, and recreational opportunities such as bushwalking, picnicking, and birdwatching.
- Ecological significance: The area supports a variety of endemic species and forms part of the larger Jarrah forest ecosystem. Management practices aim to balance water resource needs with conservation objectives.
Governance and Safety
- The Water Corporation conducts regular inspections, monitoring, and maintenance in accordance with the Australian National Committee on Large Dams (ANCOLD) guidelines.
- Emergency action plans are in place to address potential overtopping or structural concerns, though no major safety incidents have been recorded in recent decades.
See Also
- Canning River (Western Australia) – the river impounded by the dam.
- Water supply in Western Australia – overview of the state’s water resource infrastructure.
Note: Information presented reflects the most reliable and publicly available sources as of the date of this entry. Where specific technical details are not publicly disclosed, the entry notes the limitation accordingly.