A $1.8 million budget blowout to build a new link into Tauriko's fast growing industrial area will end up costing city ratepayers about $600,000.
The new rates-funded debt was caused by a shortfall in development fees needed to cover the full cost of bridging the Kopurererua stream.
It increases the amount of development debt transferred to ratepayers last week to $3.1 million.
Council's last big meeting before the elections also saw ratepayers lumbered with an additional $2.5 million of debt to meet a shortfall in revenue from development fees, once some of the current urban growth areas were fully developed.
The $600,000 bridge portion of new rates-funded debt stemmed from a 50 per cent blowout in the $3.4 million estimate to build the bridge near the southern end of The Lakes.
Council project management team leader Steve Wiggill said the bridge had been fast-tracked to meet developer deadlines. However, awarding the contract had been "curtailed" after tenders exceeded the budget approved last year.
He said the original budget was drawn up before detailed hydraulic studies were done and before details of land developments in the area were known.
"Final detailed modelling required a bridge roughly twice the size of the outline design," he said.
Factors which contributed to the extra $1.8 million were the tendered price, costs to date, the regional council's request for more hydraulic modelling, and professional services for monitoring, surveillance and quality assurance.
Mr Wiggill said rapid growth meant complex projects were being brought forward without sufficient time and resources to plan and cost them properly. The council was now looking at ways to improve the depth and quality of the planning of its capital projects.
"Additional resources are currently being recruited and a number of initiatives are being implemented."
The bridge was originally to be funded by development fees but because some of the growth in the catchment had already occurred, some costs would need to be recovered from rate-funded debt.
Neighbouring developers were anxious that the work be completed to allow adjoining lots to be sold. Approval of the consent was imminent, he said.
Council's strategic finance and growth manager Frazer Smith said the $600,000 was in addition to the council's other decision to transfer $2.5 million from development fee-funded debt to rates-funded debt in the 2017-18 Annual plan
He said the $2.5 million backlog was calculated to June 30 this year, before he became aware of the bridge increase.
However, the $600,000 was unlikely to have much impact on the $2.5 million of rates funding recommended for the 2017/18 budget. This was because the amount may change depending on the speed of growth at Tauriko.
Mr Smith said the council tended to fund shortfalls once a growth area was predominantly full, but Tauriko was still only about a third full.
''We are recovering the backlog over time, so the impact would be spread over a number of years.''