Leaving the environment in better shape

Environmental

Nov 17, 2016

Constructing an 18km, four-lane expressway in an archaeologically and ecologically sensitive area is no small feat. But add in 25 separate waterways and seven contaminated sites and you have a project that demands some serious environmental smarts.
Faced with this challenge, the alliance delivering the $630m MacKays to Peka Peka Expressway on  Wellington’s Kapiti Coast set a goal to not only construct the project with minimal disruption, but to leave the natural environment in better shape than when they started.
Through videos, inductions, site report cards, toolboxes and job safety and environmental analysis, the M2PP Alliance has instilled a strong environmental culture on site, where all staff are encouraged to take ownership of protecting the environment.

The project’s legacy will be over nine hectares of wetland habitat and 140 hectares of new planting, including 1.5 million locally eco-sourced plants. For every acre of wetland reclaimed for the expressway five acres will be constructed to replace the lost wetland.

Key environmental initiatives included:
•    Relocation of skinks and geckos to new, natural habitats prior to construction 
•    Relocation of thousands of native fish and eels prior to working in waterways, and designing bridges and crossings so that fish and other species can move freely 
•    Consistently high scores in weekly environmental inspections undertaken by GWRC
•    Extensive use of erosion and sediment control measures
•    The project was hit by two severe flood events which tested the resilience of the erosion and sediment control measures. 100 M2PP staff worked through the day and night to help Kāpiti Coast District Council (KCDC) and police place sandbags, re-route traffic, assist with road closures, monitor phone lines and protect people’s homes from rising flood waters
•    A section of the site was a former uncontrolled landfill, containing approximately 6,000 m3 of material contaminated with varying levels of arsenic, asbestos and hydrocarbons. The team installed Geotextile clay liners (GCL) to prevent further contaminants being eroded into the environment.
•    Archaeological investigations and monitoring
•    Installation of a CO2 dosing system to manage the highly alkaline water from the precast yard – without the need for harsh chemicals.