Landowners served by flood-protection and drainage works on the Taieri Plain and Clutha delta may soon face costs in the millions of dollars to replace ageing and failing equipment.
A report identifying necessary renewal and replacement requirements over the next 10 years has been presented to the Otago Regional Council's engineering and hazards committee this week.
Environmental engineering and natural hazards director Dr Gavin Palmer told the committee the suggested works would only maintain the status quo to a satisfactory level of reliability, not enhance the schemes.
Much of the pumping and drainage infrastructure was old and either at the end of its useful life or near this point.
Some equipment was obsolete and very difficult to maintain.
"It's a proactive approach.
''We want to pre-empt failure rather than react."
The Taieri was served by seven pumping stations aged from 12 to 80 years old and the Clutha delta by five, aged between 11 and 60 years old.
Investment would be required, particularly in the next five years in the West Taieri area, where typically only about $20,000 a year was spent on maintenance, Dr Palmer said.
However, soon the area could be looking at needing $2 million in capital expenditure, although the cost of the work had yet to be calculated.
Flood protection and drainage works were covered by special rating areas, which meant those who benefited from the schemes met the costs.
Corporate services director Wayne Scott said large capital costs were likely to be funded by borrowing and paid off over time through rates.
The funding implications were being prepared for consideration as part of next year's Long Term Council Community Plan and annual plan.
The idea was to achieve a degree of standardisation across flood protection schemes so equipment was interchangeable with that in other systems.
Cr David Shepherd said it highlighted the need for an ongoing capital maintenance programme.
"There is a significant cost involved and I know from speaking to farmers it causes some concern."
Cr Stephen Woodhead said it was good to see the new Waipori D1 pump operating, at a cost of about $395,000, but he now wondered about the area's second pump.
Mr Scott said the West Taieri Drainage Scheme Liaison Group had decided not to fund depreciation, preferring to wait until the work needed to be done.
"Now the day has come."
The report will go to the Lower Clutha Scheme Liaison Group and the West Taieri group for consideration.
