The Wairau River originates high in the Spenser Mountains, part of the Southern Alps, and winds north between St Arnaud Range and Raglan Range, where it marks the eastern boundary of Nelson Lakes National Park. The river then heads northeast, along the Wairau Valley through inland Marlborough before emptying into Cook Strait at Te Koko o Kupe / Cloudy Bay on the northeast side of the South Island. It is approximately 170 km long, making it the second longest river in the upper South Island, after the Buller River at 177 km.
The river is fed by alpine meltwaters and tributaries, and as it enters the Wairau Valley, it becomes a significant braided river. In places, the exposed gravel beds are up to 2.5 km wide. Over millennia, the river has deposited massive gravel and silt terraces, creating the wide Wairau Plain at the northern end of the Wairau Valley and providing some of New Zealand's best viticultural soils. The river also shaped the Wairau Lagoons and the surrounding marshland around its mouth through sediment deposits.
The Wairau Bar on the west side of the river's mouth is archaeologically significant with some of the earliest known Māori settlements, dated at around 1280. European settlement along the river valley from the 1840s cleared scrub and forest and drained most of the marshland, allowing for pastoral farming. Over the last few decades, pasture has been progressively displaced by vineyards. The river was also important for transport for Māori and Europeans. The river mouth is negotiable in a boat at high tide, and the last commercial use of the river was as late as the 1960s by the Echo.
For today’s visitors, the Wairau River offers scenic walks, picnic spots and fishing. One popular spot is from the bridge behind Spring Creek (just north of Blenheim), where you can park and walk north on the Bothams Bend Track for about 1.5 km beside the river, with beautiful braided channels, birdlife, and open floodplain views. There is also the nearby Wairau Diversion, a substantial man-made channel with a public reserve, which directs water from the river during high-water events more directly to Cloudy Bay.
Further downstream, the parking area at Wairau Bar Road gives access to the coastal edge and mouth where the river meets Cloudy Bay. There is a large public reserve, and you can see the wreck of the SS Kennedy. On the other side of the river mouth are the lagoons and marshlands. These can be accessed on Harding's Road, with the Wairau Lagoon Walkway loop to the wreck of the Waverley.
From Blenheim, the drive southwest into the Wairau Valley along State Highway 63 runs parallel to the river in places, but access points and views are surprisingly limited, albeit the valley is very scenic. There are only two bridges on the way to St Arnaud: the one on State Highway 6, north of Renwick, and the Wash Bridge, 90 km to the southwest, where you will get the best views. A better option for river views is Northbank Road, accessed just north of the bridge on State Highway 6. This road provides close proximity to the river in several locations and access to numerous tracks in the Richmond Range, including the Enchanted Lookout, which provides high views of the river and valley, Lake Chalice, and Omanalutu Reserve.
For a more adventurous option, head to where State Highway 63 leaves the valley, and continue alongside the river and into the Wairau Gorge on Rainbow Road. This becomes a remote gravel road, then 4WD with a toll gate. It is a remote 4-hour drive to Hanmer Springs from here.
