Bart Schultz
Australia comprises the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. Surrounded by the Indian and Pacific Oceans, Australia is separated from Asia by the Arafura Sea and the Timor Sea, and from New Zealand by the Tasman Sea. The country has a surface area of 769 million hectares with a population of approximately 25 million, or 0.033 persons per hectare.
New Zealand consists of two large landmasses – the North Island and the South Island – and approximately 600 smaller islands. The country has a surface area of 26.8 million hectares, with a population of approximately 5.2 million, or 0.19 persons per hectare.
Australia's climate is significantly influenced by ocean currents, including the Indian Ocean Dipole and the El Niño-Southern Oscillation, which is associated with periodic droughts, and the seasonal tropical low-pressure system that produces cyclones in Northern Australia. These factors cause rainfall to vary considerably from year to year. A large part of the northern region of the country experiences tropical, predominantly summer rainfall (monsoon). The southwestern corner has a Mediterranean climate. The southeast varies from oceanic (Tasmania and the coast of Victoria) to humid subtropical (upper half of New South Wales).
In much of the continent, major floods regularly follow prolonged periods of drought, causing inland river systems to be washed away, dams to overflow, and large inland river plains to become submerged, as occurred throughout eastern Australia in 2010, 2011, and 2012 following the Australian drought of the 2000s.
The climate in New Zealand is predominantly temperate maritime, with average annual temperatures ranging from 10 °C in the South to 16 °C in the North. Conditions vary significantly from region to region, from extremely wet on the west coast of the South Island to nearly semi-arid in Central Otago and the Mackenzie Basin in interior Canterbury, and subtropical in Northland. The southern and southwestern parts of the South Island have a cooler and cloudier climate. The general snow season runs from early June to early October, although cold spells can occur outside this season as well. Snowfall is common in the eastern and southern parts of the South Island and in mountainous regions throughout the country.
The size of Australia has resulted in a wide variety of landscapes, with tropical rainforests in the Northeast, mountain ranges in the Southeast, Southwest, and East, and a desert in the Centre. Eastern Australia is characterized by the Great Dividing Range, which runs parallel to the coast of Queensland, New South Wales, and a large part of Victoria.
Schrale and Desmier (1983) describe that Charles Sturt recognized the potential of the river plains for agricultural development in 1829. About fifty years later, the first attempts of land reclamation were undertaken using relatively ineffective dikes that prevented minor floods and allowed for temporary grazing.
By the beginning of the 20th century, land reclamation began in earnest, and by 1929 all suitable wetlands along the downstream sections of the Murray-Darling river system had been reclaimed. In 1940, dams at the estuary were completed to prevent tidal intrusion. Since then, the river level between the last two weirs has been kept approximately one metre higher by controlled discharges from reservoirs in the upper part of the river basin area.
The Polder Development Group of Delft University of Technology (1982) mentions two polder areas in Australia. The first is an agricultural polder of 5,000 ha at the mouth of the River Ord. The other concerns a group of twenty polders with a total area of 5,200 ha along the Murray-Darling river system, which were primarily developed for dairy farming.
New Zealand's varied topography and sharp mountain peaks are largely due to the country's tectonic uplift and volcanic eruptions. New Zealand is long and narrow. The country owes its varied topography, and perhaps even its rise above the sea, to the dynamic boundary extending between the Pacific Ocean and the Indo-Australian Plate.
In New Zealand, one polder area has been identified. It also concerns an agricultural polder in the Eastern Waimea Mudflats with an area of 3,200 ha.
In 2006, my wife and I visited the South Island during our holidays and made a stop in Nelson on the east side of the Waimea Estuary. There, we discovered a large statue of Abel Tasman from Lutjegast in Groningen. According to the text beneath the statue, he stayed in the area between December 13, 1642, and January 6, 1643, and on December 19, 1642, he and his crew became the first Europeans to meet the Maori. The encounter must have been pleasant, as next to the statue there is the Abel Tasman National Park, Tasman Bay, the Abel Tasman Coast Track, and Tasman River Tracks. It is truly astonishing that someone from a small rural village in the Netherlands, along with his crew, managed to reach the other side of the world by sea even back then.
