The council approved the $14.7million project at its meeting yesterday.
The project is designed to "future-proof" the water supply and ensure the town’s drinking water meets New Zealand’s safety standards.
The Cromwell Water Treatment Plant, located on Alpha St Reserve near Lake Dunstan, serves the local communities of Bannockburn, Lowburn, Ripponvale, and the southern part of Pisa Moorings.
However, as population growth and employment opportunities surge, the plant has become insufficient to meet the growing demand. More concerningly, the plant does not meet the New Zealand Drinking Water Quality Assurance Rules, particularly in terms of protozoa treatment, which can lead to serious health risks, such as gastrointestinal illness.
To address these challenges, the council has developed a $15.3m water upgrade programme, included in the CODC 2021-2031 Long Term Plan.
The comprehensive upgrade will introduce ultraviolet (UV) treatment alongside the existing chlorination process, effectively protecting against harmful bacteria and protozoa while maintaining the quality and taste of the water.
One of the notable design changes since planning the project began is the relocation of the water treatment facility from its lakefront location to a site on McNab Rd site.
If approved by council, procurement and construction of a new treatment plant at the reservoir site in McNab Rd and upgrade of the bores between Lake Dunstan and the Alpha St will begin with a publicly notified tender process.
The project is viewed as a major step in securing Cromwell’s water future as the region experiences rapid growth.
The water upgrade includes the construction of a new water treatment plant, an upgraded borefield, and the completion of a newly installed raw water pipeline.
With these essential components, the plant will be able to meet the needs of a projected population surge over the next 30 years.
The total cost for design, construction, project management, and commissioning of the treatment upgrade is estimated at $14.7m, with the budget set at $15.3m for the water treatment and borefield improvements as outlined in the 2024 Annual Plan and the 2025 Long Term Plan.
Decommissioning the existing treatment plant at Alpha St Reserve, including removal of pumps, tanks, and associated infrastructure, is estimated to cost around $160,000.
This will involve filling subsurface cavities with topsoil and grass and reusing certain components, such as safety showers and dosing pumps, for future use.
The census forecast Cromwell’s population to nearly double in the next three decades and peak day water use to rise significantly.
The high-growth scenario, used for infrastructure planning, estimates that the population will rise from 17,685 on peak days in 2024 to 37,002 by 2054.
The new borefield will play a critical role in meeting this demand, while consolidating the water supply for Pisa Village with Cromwell’s system, improving operational efficiency and security as well as reducing costs.
In his report Mr Keenan said the move would improve both security and operational efficiency and help protect the scenic values of the area.
The upgrade is designed to meet Cromwell’s needs for the next 30 years and additional upgrades are planned for the next 18-24 years to ensure scalability.
