A North Otago irrigation company is spending $750,000 to build a new intake and piping after its old intake was destroyed by the Waitaki River flooding this year.
Shareholders in the Maerewhenua District Water Resources Company, which irrigates about 900ha around Duntroon, are footing the cost but also future-proofing the scheme by increasing its capacity to meet demand.
The new works are on farmer Geoff Keeling's land. Mr Keeling has lost about 3.5ha of river frontage land to flooding.
The old intake was destroyed when the Waitaki River reached 800 to 1100cumecs in January and February. The average flow is about 360cumecs.
Company chairman Kelvin Weir said the river broke through a side stream and washed away the headrace, by-wash area and several hectares of land.
"We tried to tie willows into the bank to protect it, but the flood waters were too strong. The scheme and landowner contracted a bulldozer to divert water towards the main flow of the river," he said.
About half the flow, with Environment Canterbury assistance, was later diverted.
The intake was previously an open race controlled by relatively new Rubicon gates, but is being replaced by 750m of piping, with new Rubicon gates within the pipes. The new intake is about 200m upstream and and changed to reduce the chance of flood damage. It includes a fish screen.
The pipes are 1350mm in diameter, with a carrying capacity of 1600 litres per second, an increase on the 1200 litres per second of the old race.
Mr Weir said what happened illustrated how big the Waitaki River was, and how prolonged high flows led to losses of productive land and infrastructure.
Mr Keeling had lost about 3.5ha of productive land, with irrigation and production to a further 15ha interrupted until the race was replaced. He bought the land shortly before the flooding and, although trees were planted to stabilise the bank, they were not established enough to provide protection.
Work is due to be completed in about three weeks.
