The Willunga Basin Pipeline is a large reclaimed water scheme which is owned and operated by its water users. Despite being funded without government assistance, it continues to expand, providing a catalyst for economic growth, replacing stressed groundwater and reducing nutrient discharge to the sea.
Like the fine wines of the region, it seems this scheme gets better with age.
HydroPlan has been instrumental in this scheme which has grown from 17 commercial users to over 190. Much of the success is attributed to the simple and smart engineering concepts developed from HydroPlan's knowledge of water user requirements.
Water is given greatest value when it is delivered with minimum fuss and maximum reliability. Growers can irrigate by just turning on their tap. There is no need to 'order water', and there is no need for storage, pumps or power on-farm.
The first water users formed a Joint Venture and company (Willunga Basin Water) to build Stage 1 of the pipeline so that they could pursue their core business of irrigated horticulture (mostly viticulture). Over the following 15 years, the scheme expanded every year so that their neighbours could access water as well. In 2013 WBW was purchased by Water Utilities Group.
The primary water source is the Christies Beach Wastewater Treatment Plant which is 10 km north of the Willunga Basin, and is one of 4 metropolitan treatment works. From late 2004, treated effluent from the local towns of McLaren Flat, McLaren Vale and Willunga has also been injected into the scheme. From 2008, treated water from the Aldinga WWTP was added as well.
In the absence of significant "winter" storage, small quantites of groundwater and mains water were used in peak periods. WBW continues to seek opportunities for winter storage and was a key participant in Waterproofing the South and Aldinga Managed Aquifer Recharge (ASR). These above and below-ground storages made it possible to expand the summer supplies by several gigalitres.
But more is planned. There is sufficient 'waste' water flowing to sea from CBWWTP to replace the annual abstraction of groundwater for irrigation in the Willunga Basin.
The Willunga Basin Pipeline is a triple-bottom-line role model. It made no draw on public funds, it delivers high value to the community, and it reduces nutrient discharge to the ocean whilst replacing water consumption from aquifers and the Murray.