Wairau River

The Wairau is Marlborough's largest river, with more than 140 km of fishing water. It starts as a remote headwater in the Spenser Mountains along Rainbow Road, swings east past St Arnaud, and braids its way down the long Wairau valley to the sea near Blenheim. Brown trout carry it from top to bottom. The middle river's browns average about 1.4 to 1.8 kg (3 to 4 lb), and the headwaters hold fewer but trophy-sized fish. Below Renwick the lower river adds sea-run browns from February and a run of quinnat salmon from late January to April. The upper river and its tributaries above Six Mile Creek, the Rainbow River among them, are a Designated Water, so you need an extra licence there.

The water is usually tinged turquoise with fine silt from the mountains, and spring snowmelt colours it heavily early in the season. After that it can stay discoloured for long spells, so watch the gauges before a long drive. About 80 km of the middle river runs across a wide, open valley as a web of channels. It is mostly wadeable, but the stones shift underfoot. Fish a Hare and Copper, a stonefly or a Pheasant Tail nymph in size 14 to 16, and a Royal Wulff or a Coachman in size 10 to 12 when fish rise. In the headwaters, weight the nymphs heavily for the deep pools. The lower river is wide and slow with fewer defined runs. During the whitebait season, from about September to December, a Grey Ghost works there by day and a dark lure at night. Flows are read at Dip Flat on the upper river and at Barnetts Bank, near Tuamarina, for the whole lower river. As a rough guide, the lower river wades at about 15 to 60 m³/s at Barnetts Bank and is blown out past about 150.

The upper river is reached on Rainbow Road, a toll road across Rainbow Station that leaves SH63 near St Arnaud. It needs a high-clearance 4WD, has unbridged streams that rise in rain, and can close without notice for snow, slips or fire risk. The middle river is reached by signposted side roads off SH63, and the lower river by side roads off SH6, about 15 minutes from Blenheim. Above Wash Bridge the river is fly and spin only, open 1 October to 30 April. Below it, the river is open all year to fly, spin and bait, with a bag of 2 trout and 1 salmon. When the Wairau runs dirty, the Goulter, a bush-lined tributary that joins near Argyle, is generally clear, but you may keep only one trout from it.