As urban development encroaches on agricultural land, the management of water resources becomes increasingly critical for ensuring agricultural productivity and community well-being. In response to this challenge, the Bunyip Water Scheme emerges as a beacon of innovation, harnessing clever technology applications to increase crop yields and security via the reliable water supply, irrigate parks and open spaces for community benefit and reduce the impacts of flash flooding via stormwater diversion and harvesting.
With its second stage underway, this scheme promises to significantly expand with more water supply, a larger and more sustainable customer base and significantly increased community downstream safety and benefit. Its $15 million budget is jointly funded by the federal government, Light Regional Council and Bunyip Water Pty Ltd, and is due to be completed and commissioned in late 2024, ahead of the 24/25 irrigation season.
The original Bunyip Scheme (Stage 1), completed in 2016, was a significant step towards sustainability. It aimed to substitute at least 800ML/annum of Murray River water in the Barossa with urban stormwater harvested from the Gawler River during significant flood events. This has improved primary production for viticulture in the Barossa region and reduced flooding in the Gawler River, which had been exacerbated by urban development. The scheme, with approval to harvest up to 1,600ML/annum from Gawler River flows above an environmental threshold, primarily stores water in several dams, with a managed aquifer recharge trial for future expansion, thus highlighting its environmental benefits.
Stage 2 of the scheme builds new extraction infrastructure, including pumps and pipes, for up to 800ML/annum from new stormwater retention basins that capture stormwater runoff from the new Roseworthy town expansion development. The basins and offtakes will significantly reduce flooding in the Gawler River and downstream areas and have allowed for the sustainable expansion of the Roseworthy township. This runoff water is then treated in a new, ultramodern water treatment plant before being piped to existing storages, including the managed aquifer recharge constructed during Stage 1.
Treated water supply pipes have also been provided to supply irrigation water for the new Roseworthy town development, including open parks, gardens, schools and playing fields, together with the industrial areas to the north, as paying customers of Bunyip Water.
Pinion Advisory has been the project's lead consultant for both Stage 1 and Stage 2. It has provided an integrated suite of expert in-house services, including scheme feasibility, concept and detailed designs, project budget estimates, procurement of new infrastructure required and the management of a significant cohort of subcontract consultants. Pinion Advisory also has an ongoing role in the scheme's operation, including managing environmental reporting and flows, around the storage, via telemetered technology.
Managing the design and approvals of the managed aquifer recharge was particularly challenging. However, the significant benefits of underground storage, including reduced evaporative losses and less surface area usage, have given the scheme greater flexibility to store water during high rainfall periods.
As we look towards the future, the Bunyip scheme serves as a model for integrated water management, offering valuable lessons for balancing the needs of agriculture, urban development and environmental conservation.