A digger moving some of the debris that has come out of the Kaipatangata Stream. PHOTO/CHELSEA BOYLE
By Chelsea Boyle
The flash flooding that wiped out the water intake infrastructure on the Kaipatangata stream has been called a “once in 20 years” weather event, and its cost to the Carterton District Council is yet to be known.
Carterton has been relying on its supplementary bore system for almost three months after the February 18 downpour brought massive beech logs tearing down the stream.
The logs are thought to have caused a lot of the damage to the infrastructure.
Further downstream, the flooding closed Dalefield Rd.
Carterton District Council (CDC) operations manager Garry Baker said they should be able to return to the primary water supply soon.
He said a staff member who had been working “40 odd years” for the council had never seen anything like it.
Mr Baker said that they “could be looking at $10,000 to $20,000” for the cost of his staff’s wages and materials alone.
They had hoped to fix the problems with the Kaipatangata water supply within weeks, but Mother Nature had other plans with two metres of gravel refilling the dam bed in early April during heavy rain.
Mr Baker said the setback was disheartening as contractors had made good progress in clearing the area.
“We were a fair way done, and then it came through and put another two metres over the whole area again.
“It was quite frustrating.”
For Carterton people watering their gardens on alternate days due to water restrictions, it might be hard to imagine that there have been any lucky breaks.
But the first deluge happened before council staff were due to install four fish ladders, in a process that was estimated to cost $67,000.
The fish ladders were to be installed in accordance with the Greater Wellington Regional Council consent process.
The GWRC website states that artificial structures such as flood gates, weirs, and dams can prevent native fish from completing the migration phase of their life-cycle that allow fish to reproduce.
“Artificial barriers to fish movement have contributed to the decline of our native freshwater fish populations, and the quality of our freshwater ecosystems.”
Fish passages were needed to protect native freshwater fish.
Mr Baker said they would now re-evaluate the fish ladder strategy because they did not want to put in something that would crumble during extreme weather.
One silver lining has been the amount of “good fine metal” workers have collected while clearing the stream.
This material will be used later, laid over tracks around the wastewater plant and filling the area around a new pipe that will run around the plant.
“We are stockpiling it ready for a job we are doing there.
“It is cost-saving because we would have had to get the material from somewhere.”
Mr Baker remains optimistic the work now being done on the Kaipatangata Stream is almost at an end.
“It’s getting better and better all the time,” he said.
More flushes of freshwater have been coming down the river and have helped clear the silt, he said.
“It’s more or less operational now — we haven’t sent it off to town because of the odd bit of dirtiness in the water.”
“By next week we should be fully operational up there again.”
