New Zealand Refining (Refining NZ) has received approval to dredge Whangarei Harbour in order to facilitate fully loaded Suezmax tankers. The refinery’s Marsden Point facility is at the entrance of Whangarei Harbour, which is situated on the east coast of North Island. The Northland Regional Council, which governs New Zealand’s northernmost area, has granted resource consent to the proposed Whangarei Harbour dredging project, which is budgeted at NZD57 million (USD38.2 million).
Refining NZ wants to dredge up to 4 m in parts of the outer and inner shipping channels and up to 8 m in targeted spots around the refinery jetties to allow for fully loaded Suezmaxes to berth at the port. Dredging is expected to commence in 2020, after contractors are appointed, and is estimated to take six months to complete. The company commissioned Royal HaskoningDHV to carry out a study to determine how the channel could be dredged and its potential environmental impact, chiefly the effect on the stability of nearby Mair Bank.
The assessment showed that the project is unlikely to have any significant adverse effects on the environment and is generally consistent with the relevant statutory planning documents and provisions.
Refining NZ said, “This critical project will improve freight economics and, hence, the company’s refining margin, by allowing larger crude cargoes of about 1 million barrels to be shipped to Marsden Point.”
Current draught limits mean that Suezmaxes can enter Whangarei Harbour only if the tankers are 90% loaded. Alternatively, fully loaded Aframaxes can also carry crude to Refining NZ, but these tankers carry a maximum of 700,000 barrels. The company was quick to point out the benefits of the project. “To keep Marsden Point running – and jobs in Northland – our fuel products need to be of the highest quality and cost competitive with imports. Bigger cargoes would reduce the cost of transporting crude oil to the refinery. The proposed changes will help us keep pace with imports from increasingly competitive Asian ‘mega-refineries’.”
Dredged material, mostly sand, will be relocated to sites where the seabed comprises similar sand. The expected dredge volume is 3.7 million m³ over 1.95 km².
Local hapu (Maori political leaders) had expressed concern about the effect of the dredging works on kaimoana beds and other harbour issues. They also cited worries about the potential for oil spills and accidents linked to larger Suezmax tankers, as well as the dredged material being disposed near Mair Bank, the Motukaroro Marine Reserve, and other sensitive ecosystems.
Independent commissioners who heard Refining NZ’s application concluded that any residual adverse effects that are unable to be avoided have been appropriately offset and compensated.