Clean Water Discharge, No Matter What the Tide is Doing: Seawall Renewal

Massey Road on Wellington's Miramar Peninsula is one of the city's most scenic coastal routes, connecting Shelly Bay and Scorching Bay along the harbour edge. It's also a road that relies entirely on a seawall to stay in place.

Three sections of that seawall, totalling 220 metres, needed replacing. Condor is on site supporting Downer to make sure the water coming off the job never becomes the problem.

The Project

Wellington City Council engaged Downer to renew three seawall sections along Massey Road, at Mahanga Bay and two locations in Kau Bay near Point Halswell Lighthouse. The work involves demolishing and removing the existing walls, earthworks, installing new concrete mass block walls, road reinstatement, a new safety barrier, drainage improvements, and habitat reinstatement.

Construction began on the first seawall in March 2026, with all three walls expected to be completed by October 2026. To allow the work to proceed efficiently, Massey Road has been closed to motorists between Shelly Bay and Scorching Bay from June through to October 2026.

The Challenge

Working right on the Wellington Harbour waterfront introduces a challenge that doesn't exist on a standard roading or civil job: the tide.

Tidal fluctuations mean water ingress on site is constant and unpredictable. The volume coming in changes with every tide cycle, and every litre of water that leaves the site has to meet discharge consent requirements before it reaches the harbour. Working 220 metres of seawall in that environment means the dewatering and treatment setup has to keep up, reliably, around the clock and regardless of conditions.

The Condor Solution

Condor deployed two pieces of equipment working together to manage water on site throughout the seawall construction programme.

6D AEON Dewatering + Sewer Pump handles water ingress on site, extracting water continuously as it enters the work area through tidal influence and groundwater movement. The 6D AEON is built for exactly this kind of demanding, high-continuity dewatering application, with reliable performance across variable flow conditions.

Condor XXL Water Treatment System receives the pumped water directly from the 6D AEON and treats it to a compliant discharge standard before it leaves site. The XXL's lamella clarifier technology settles suspended solids efficiently, ensuring the discharge meets environmental requirements regardless of what the tide is doing or how much sediment is moving through the site at any given time. 

The two units working in combination means the team can operate confidently through tidal fluctuations without stopping to assess discharge quality or risk a consent breach. The water is managed, treated, and gone, so the focus stays on the seawall.

Why It Matters

The renewed seawalls will protect a critical piece of Wellington's coastal transport network for decades to come. Getting the environmental management right during construction is just as important as getting the walls themselves right, particularly on a site this close to the harbour and in an area used by cyclists and pedestrians throughout the construction period.

Condor's role is to make sure the water side of the equation never becomes a reason to slow down or stop.

We're proud to be supporting Downer and Wellington City Council on a project that keeps one of the capital's most iconic coastal roads safe and resilient for the long term.