Erosion and sediment control

Water treatment plant at Mt Eden site

In order to protect surrounding waterways, systems to manage erosion and sediment have been established on all CRL construction sites. This includes soil characteristic assessments, and establishing flocculation and sediment control systems.

Water treatment at Link Alliance

Six water treatment plants were installed and commissioned across all Link Alliance sites in 2020. Water treatment plants (WTPs) ensure that site rainwater and ground water are free of sediments and any other potential pollutants, before being discharged into the stormwater network.

The major difference between Link Alliance's WTPs and those on other projects, is that they have been set up so that water, once treated, can be reused on-site. This helps ease the pressure on Auckland's water infrastructure.

Recycled water from the Mt Eden and NAL sites is used for general activities such as soil mixing, cleaning and dust control. To date, no water has been discharged from the NAL site, and in recent months recycled water makes up approximately 20 per cent of Mt Eden's entire water use. At Aotea, the team has now started collecting rainwater from roof areas for reuse. The Link Alliance will continue to ramp up water recycling across all its sites as WTPs are established.

The systems that control WTPs are also being updated to include online monitoring to automatically adjust pH, measure flows and allow remote access and control. Left: Influent - Site water prior to entering WTP Centre: Flocculated - Introducing flocculants Right: Discharged water leaving the WTP