In the late 1980’s, population and tourism growth in Hervey Bay had created the need for more sewage treatment facilities. The Environmental Protection Agency would not permit the extra treated sewage to be discharged to local creeks that flow into the bay - an ocean outfall was required. However, in a community where tourism relies on preserving the pristine waters of the region, any impact on the bay was considered unacceptable.

The challenge was to find an environmentally responsible solution that was both economically viable and acceptable to the residents of Hervey Bay. The result is a land-based effluent disposal system that has not only protected the waters of the region, but has also delivered dividends for local farmers, the Council and ratepayers.

How it works

The scheme consists of three parts - The Pulgul Irrigation Scheme, the Eli Creek Irrigation Scheme (both joined by a 12.5km pipeline) and a stormwater harvesting project.

Pulgul

The Pulgul Irrigation Scheme began as a trial in 1990. Wide Bay Water Corporation purchased a 485-hectare farm to demonstrate the feasibility of irrigating sugar cane, pasture, a eucalypt plantation and tea trees. All trials were successful, and the impact on the cane farm was particularly remarkable, moving from one of the poorest performers to become the area’s productivity winner.

Eli Creek

The success generated interest amongst other farmers, particularly in the sugar cane industry. The Corporation purchased a further 320-hectares and established a Water Board to develop and manage a similar irrigation scheme for the Eli Creek catchment. Within the first year, cane farms using wastewater irrigation showed significant improvements in yield and return (45% increase in tonnes of cane/ha, 62.5% increase in tonnes of sugar/ha and an 80% increase in $/ha). The scheme was expanded in 2002, and a pipeline was built to connect it to the Pulgul scheme. The integrated scheme handles 8 million litres of effluent a day and incorporates five storage facilities, including an 850 ML storage dam. A 26.5km system of pipes carries the wastewater to ten cane farms, two turf farms, two golf courses and a flower farm. In addition the treated water irrigates landscaping at the Hervey Bay airport, Wide Bay Water Corporation offices and a nearby cricket ground, and will also service 380 hectares of hardwood plantation, under development.

Stormwater harvesting

To manage the situation where demand might exceed supply, Wide Bay Water Corporation has incorporated a stormwater harvesting scheme to provide additional water for treatment if necessary - particularly during the peak cane growing period from November to April. Stormwater is stored in flood retardation basins around the city, then released into the sewer during lower night-time flows. This innovative engineering approach helps minimise odour and corrosion in the sewerage network, while preventing contaminants such as oil, animal waste, fertilisers and litter flowing into the bay through the stormwater system.

Wide Bay Water Corporation uses about 80% of its wastewater in the irrigation scheme. Its EPA licence stipulates 90% reuse by 2007 - but the Corporation’s goal is to continue expanding the scheme’s customer base to recycle 100% of effluent.