Christchurch is the largest city in New Zealand’s South Island, and the chief city of the Canterbury region. It has a population of 380,000.
Christchurch city itself is generally flat. It lies on the coastal fringe of a broad alluvial plain. Three physical features however make it an attractive city for locals and visitors: the Port Hills; the coastline; and the city’s rivers.
Extinct volcanoes on the doorstep
The Port Hills are on the south side of Christchurch. They mark the start of the hill country of Banks Peninsula. The peninsula is the prominent thumb protruding into the Pacific Ocean halfway down the eastern side of the South Island.
Banks Peninsula is the eroded remnant of several basaltic ‘Hawaiian’-type volcanoes, active 12 to 6 million years ago, but now long extinct.
Lyttelton and Akaroa harbours are fine examples of erosion craters, now invaded by the sea. The peninsula is a picturesque blend of high craggy hills, deep valleys running down into long bays, pastureland and patches of forest.
Rivers in Christchurch
Two small spring-fed rivers thread through the city: the Heathcote and the Avon. The latter meanders very prettily through the city centre.
The two rivers flow into the Avon-Heathcote Estuary on the city’s eastern side. This is a feeding ground for a range of wetland and wading birds, including some of the world’s great long-distance migrators.
Within easy reach of the mountains
If you travel in a north-westerly direction from Christchurch across the plains, you will encounter the first ‘foothills’ after 50 kilometres (30 miles). However you need to travel a further 100 kilometres (60 miles) through the mountainous Canterbury high country before you reach Arthur’s Pass, one of the few road and rail passages through the main range (or ‘Main Divide’) of the Southern Alps.
The Southern Alps are the dramatic result of a collision between the Australian and Pacific tectonic plates. Some of the most rapid tectonic uplift in the world is cancelled out by equally rapid, massive erosion in the mountains. There is plenty of evidence of erosion in the form of long scree slopes off the peaks, and wide gravel-chocked ‘braided’ river beds.
From the Southern Alps, a further 100 kilometres or so north-west will bring you to the wild Tasman Sea on the South Island’s West Coast. This is a far cry from the manicured gardens and gentle streams of Christchurch.