Work to start soon on Dudley Creek bypass

Contractors working on a scheme to reduce flooding in the Dudley Creek area have started taking delivery of the giant box-shaped concrete pipes that will be used to divert water from the creek to the Avon River during heavy rains.

The pre-cast concrete pipes - which measure four metres wide by two metres deep - will be laid end-to-end to form an 800 metre long underground piped bypass.

Nearly 500 sections of pipe - each weighing between four and five tonnes - will be needed to create the bypass, which is part of a $48 million remediation scheme aimed at reducing the risk of Dudley Creek flooding. When completed in mid 2017 the scheme will reduce the risk of flooding to more than 585 properties.

The piped bypass will run south of Petrie St and east along Randall and Medway streets to the Avon River.

Contracting company, Downer, will begin excavating the ground and laying the first sections of pipes in the next couple of weeks. They will be working from both ends of the bypass route in order to progress construction as quickly as possible.

The goal is to have the bypass completed by the start of next winter.

Christchurch City Council Land Drainage Manager Keith Davison said when completed the piped bypass would be one of the biggest in New Zealand. It would be dry most of the time as it was only designed to be used in heavy rainfall events when there was a risk of Dudley Creek overflowing.

In those circumstances it would divert water from the creek to the Avon River. Its size meant it would have the capacity to handle over eight cubic metres of flood water every second.

“The bypass is a key component of the land drainage work we are doing in the Dudley Creek area and will significantly lessen the risk of flooding for nearby properties,’’ Mr Davison said.

Find out more about the Land Drainage Recovery Programme.