For the past month, a 460 horsepower bulldozer has been repairing some of the damage caused by April and May floods on the Rangitata River. The Rooney Contracting 56 tonne machine completed most of the important repairs to flood protection works at the end of last week.
The May flood was the largest in the river for 14 years.
The work is being managed by Environment Canterbury’s Timaru staff, who co-ordinate flood protection work on behalf of landowners living along the river. These people pay a targeted rate for river protection works.
They have agreed to spend an extra $110,000 to carry out repairs on the Rangitata River following the floods on April 29 and May 17.
“The required money will come out of the Reserves funds of the river rating district that landowners contribute to,” said Environment Canterbury chair of hazards portfolio committee Cr Jane Demeter.
“The April flood had a peak flow of 1200 cubic metres of water per second (cumecs),” said ECan senior engineering officer Bruce Scarlett. “The May flood was the biggest since December 1995, peaking at around 1650 cumecs. The normal flow is around 60 - 70 cumecs.
“A lot of the damage resulted from the two large floods occurring in quick succession. The first flood loosened up and shifted around a lot of the bed material in the river and the second flood, two weeks later, was deflected into and over the river bank protection works.
“As a result there was serious damage in about six places from above state highway 79, at Arundel, to the sea - a distance of about 29km.”
Bruce Scarlett said that $45,000 has been spent already, mainly in the vicinity of the main breakout about two km downstream of SH 79.
“The repair work is mostly in-stream works to redirect flows away from weak points, and new gravel banks to block off breakout points. Erosion protection plantings will follow this stage, but the in-stream works will be on-going for many years while the new trees establish and become big enough to provide protection from future floods,” said Mr Scarlett.
For further information: Bruce Scarlett, ECan Senior Engineering Officer 03 687 7800. Cr Jane Demeter, Chair Hazards Portfolio Committee, 03 365 2399.