Tighter pricing on a $117 million waterworks proposal is expected to be available in six months, but the Tauranga City Council environment committee is endorsing the Waiari scheme because it is more cost effective than upgrading existing schemes.
The endorsement is the next step in reviving a water supply scheme that has twice been put on the back burner, first by the drop in demand following the introduction of water meters, and then by the global financial crisis.
Now the city's growth is again accelerating to the point where peak daily water demand will surpass the city's ability to provide it, in less than five years.
The option includes expanding the capacity of the Oropi water treatment plant, but while existing consents allow Oropi plant capacity to be expanded to 54 million litres per day, the consent expires in 2026. The government's National Policy Statement on fresh water management leads city council staff to believe 39 million litres per day is more realistic.
The short term development of Oropi and later development of Waiari is a cheaper option but developing Waiari now, is ranked higher because there is less environmental impact developing the Waiari stream than further stressing the Waiorohi Stream at Oropi.
Councillor Kelvin Clout says Waiari is not the cheapest option but it is the most effective.
Committee chair Steve Morris agrees it makes the city's water supply more resilient.
“Water is one of those things where we get no mercy from the public if we low-ball it and go for the cheapest option. People demand and expect water to be there when they turn on the tap,” says Steve.
The next key steps involve developing detailed designs for the access ways into the site, the intake and treatment plant, and the main pipeline to Poplar Lane reservoir.
The council is also being pushed by the consent for the proposed Waiari water treatment plant lapsing in 2021, if it is not given effect.
The council will then have to apply for a new consent. The staff report says it took more than two years and ‘significant' expense to obtain the existing consent. The existing consent is good, and there's a risk a new one might not be as good for the city.
The Waiari Kaitiaki Advisory Group which was formalised as a condition of the watertake resource consent, is being reactivated in coming months. Membership includes Tauranga City Council elected members and staff, Western Bay of plenty District Council elected members and staff, Bay of Plenty Regional Council staff, and tangata whenua representatives.
The Waiari Water Supply Scheme will supply the coastal strip, allowing the Joyce WTP to supply the Pyes Pa growth area.
Costs for the water intake, raw water pipeline, water treatment plant and treated water reservoir have been updated by Council's appointed consultant. These costs have also been subject to a detailed risk analysis, providing staff with confidence over the potential range of likely cost outturns.
Costs for the remaining pipelines have been assessed internally in relation to the above costings as well as unit rates on recently completed pipeline work for Council.
The recently adopted indicative bid for funds from the government's Housing Infrastructure Fund included total costs for the Waiari of $117m. This figure includes an allowance for construction cost escalations from the current ‘best available estimates' to account for post-2017 cashflows.