Securing the Waitarakao Washdyke outlet pipes

In early April we start work on securing the pipes at  Waitarakao Washdyke. This will provide protection for the pipes and reduce the flooding risk.

The Waitarakao Washdyke is one of the few remaining coastal lagoons in Waitaha Canterbury and is an area of significant value.

We manage the pipes at Waitarakao Washdyke, which provide outlets for land drainage, some lagoon water, land and underground water. With an increase in severe weather events and rising sea levels due to climate change, the pipes are at risk of being damaged.

Remediation works

The physical works require temporarily blocking water from the pipes, removing the water from the works area by pump, and pouring concrete around the pipes. The pipes will be concealed by the concrete, as they are at the seaward end.

To maintain fish passage while the works are underway, a path will be cut from the sea to the lagoon.

This much-needed work is co-funded through the COVID-19 shovel-ready projects from the Ministry of Business, Innovation and Employment’s Kānoa Regional Economic Development and Investment Unit (64%) and the remainder by us through a combination of partner contributions and operational funding/rates.

Map description: Lozenge - works area. Orange line - access track. Thin red line - the cut that will be made to maintain fish passage. Thick red line - where the drain will be temporarily dammed.

Values of Waitarakao

The structure is located on a reef that is of high mahinga kai value for mana whenua, homing īnanga and tuna. It also hosts an impressive array of native manu including kuaka/bar-tailed godwit, karoro/black-billed gull, and tūturiwhatu/dotterel.

As a native ecological habitat, the lagoon’s importance has been colonially recognised since at least 1907, when it was gazetted as a ‘wildlife sanctuary refuge’.

Today the area continues to be used by the wider community for fishing and recreational purposes.

Five years ago, we extended the pipes inland and now, with the reinforcement of the structure, we will be helping to protect these values well into the future.

Read this feature article on Waitarakao Washdyke Lagoon - the past 80 years.

Investing in flood protection

Significant flood protection, biodiversity and community projects like this have been made possible due to the Government’s one-off COVID-19 response shovel-ready funding.

The Waitarakao lagoon is threatened by coastal erosion from rising sea levels due to climate change, and events across the country have highlighted the urgent need to remediate outdated flood protection infrastructure.

Each year, regional and unitary councils invest about $200 million in flood protection schemes. With aging structures unable to meet the levels of service expected by communities against the challenge of climate change, this is expected to fall short of what’s needed by $150 million per annum.

Read the call from Te Uru Kahika to Central Government for long-term co-investment.
What is increasingly clear is that a shared investment today means lower overall recovery costs, better protection for the environment, and for current and future generations.