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application of geographic knowledge and skills is incorporated is in the areas of town planning, Environmental Impact Statements, land use zoning, population studies, census analysis and in the large field of tourism aquaculture — the commercial growing of marine or freshwater animals and plants in water eg oyster growing and trout farming (see mariculture) aquatic — a term relating to water or living in a water environment. For example fish are aquatic animals (see terrestrial) aquiclude — an impermeable barrier that restricts the flow of groundwater in an aquifer. A rock type such as shale may restrict the flow of water from sandstone aquifer — a permeable rock formation that stores and transports groundwater and is often used for irrigation (eg the Great Artesian Basin in Eastern Australia). Different types of aquifers include: • Surficial Aquifers – occur in alluvial deposits in river valleys, deltas and some sand dunes. These large aquifers such as on Fraser Island (Qld) provide a permanent water source for many perennial rivers • Sedimentary Aquifers – occur in consolidated sediments such as sedimentary rocks as in the Great Artesian Basin covering much of the eastern half • Geologic Aquifers (or Fractured Rock Aquifer) – occur in some igneous rocks that have been modified by Earth movements and trapping some water. These are limited in extent and occur far less frequently than other types of aquifers arable — a term used to describe land that is able to grow and support crops. The land has characteristics such as gently sloping land, fertile soils and a temperate climate (one lacking extremes of temperature and rainfall)
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arboriculture — the cultivation of trees (see silviculture) arboreal — relating to trees arboretum — a collection of living plant species such as trees and ferns for both study and the display of their diversity of form archipelago — a large group of islands such as the Indonesian archipelago and Philippine archipelago Arctic Circle — an imaginary line 66½°N. North of the Arctic Circle there is one 24-hour period when the Sun does not set and one 24-hour period when the sun does not rise area reference — a four figure map reference used on a topographic map eg 2475 (see figure 40) arête — a very sharp, rocky mountain ridge in a once glaciated upland region arid environment — a dry environment. Arid environments such as deserts are characterised by low average annual precipitation and a sparse vegetation cover Aristarcus — Aristarcus of Samos (the Mediterranean) approximately 2200 years ago was the first person to suggest that the Sun rather than the Earth is at the centre of the planetary system and that all the planets revolve around the Sun rather than the Earth (see Copernicus) arithmetic mean — the average of a set of numerical data; eg scores of 5, 8, 9, 9, 10, 13 have a average or arithmetic mean of 9 – that is the sum of the scores (54) divided by the number of scores (6) arroyo — a dry river bed with steep sides in an arid or semi-arid environment. It typically flows after short intense bursts of rainfall; the term is used mostly in SW USA and Mexico (see wadi) arterial roads — the main roads transporting the bulk of vehicular traffic artesian well — a well that penetrates an aquiclude to reach the aquifer below that releases water to the
The New Geography Dictionary
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