Waimakariri River, waterway in east-focal South Island, New Zealand. It ascends in the Southern Alps and streams 100 miles (160 km) southeast to Pegasus Bay of the Pacific Ocean, 8 miles (13 km) north of Christchurch. Bolstered by its main tributaries—the Bealey, Poulter, and Esk—the waterway depletes a bowl of around 1,000 square miles (2,600 square km). The delta shaped at its mouth constitutes a noteworthy bit of Banks Peninsula and part of the Canterbury Plains. In its lower course, the stream streams in meshed channels, which avoid route and point of confinement port exercises to Kaiapoi, at its mouth. Amid the winter, the stream's upper scopes may run dry. The valley bolsters sheep brushing; grain is developed south of the stream amongst Aylesbury and West Melton. Waimakariri is a Maori expression signifying "icy water."