WESTERN AUSTRALIA, the largest of the States, occupying 975,920 sq.m. The length is about 1,480 m. and the breadth about i,000 m. while over one-third of the total area (37.3% =364,000 sq.m.) lies north of the tropic of Capricorn. Its distance from the populous eastern parts of the continent is offset by its position with regard to the ocean routes leading to the homeland, to which it is the nearest, and from which it is,—in spite of the Panama Canal—the first Australian land of call.
Physiography.—The broken coast-line of the north-west, formed by the marginal submergence of a deeply dissected pla teau, contains several fine areas of enclosed waters which flank a main gateway between the Pacific and Indian oceans. Large tidal ranges—up to 38ft. in Hanover bay—and in some cases tidal cur rents (e.g., King Sound) are a disadvantage.
Moreover, southward from this the sandy Ninety Mile Beach, and further on, the low, straggling, and often shallow inlets, promontories and islands, fringed in places by coral reefs, form part of a relatively undistinguished and inhospitable coast where exposure and silting (due partly to recent coastal ele vations) present difficulties to harbour construction. The estu ary of the Swan River forms a notable exception, Fremantle being one of the best and most commodious of natural harbours, while Geographe Bay is also relatively protected. From Cape Natural iste onwards much of the south and south-west is flanked by high, rocky and exposed coasts in which such inlets as King George Sound form excellent harbours (Albany), while further east this passes over into the unbroken cliffs of the Nullarbor Plain area (q.v.). As a whole Western Australia is a closed land-mass and has no relatively large maritime indentations.
To water-supply, owing to the climate, peculiar importance attaches. Four main, besides parts of smaller, artesian basins lie wholly or in part within the State; the Eucla or South eastern (i.e., approximately the Western Australian portion of the Nullarbor Plain) ; the Coastal Plains basin in the south-west (Cape Leeuwin—Dongarra) ; the North-western or Carnarvon basin (Gantheaume bay—Onslow) ; and the Desert or Broome basin. The extent and capacity of the Eucla and Broome basins has not yet been fully tested though they are both, and par ticularly the latter, large, and, in general, apart from the Coastal Plains basin, the resources have as yet not been fully exploited (1926: 23o bores, yielding 66,760,000 gal.; depths from 3,325-39
feet).
In the Perth area some 5o bores supply water to the city, Fremantle and adjoining districts while the northern basins largely underlie coastal lowlands and enhance their natural pastoral value. The wells in the Perth area are notably fresh, but around Eucla and some in other parts they are saline. Fresh discoveries of artesian or sub-artesian supplies are from time to time reported e.g., in the Northern Goldfields pastoral area, and there are. in addition, considerable reserves of shallow-seated sub-surface waters (e.g., in the Perth and other coastal lowlands). In the interior large areas can be made available for the carrying and movement of stock (e.g., Murchison area and cf. the Wiluna-Hall's Creek route) by means of wells many of which are natural—solu tion pits in limestones, "native wells," "gnamma holes," etc. Un fortunately these shallow supplies are saline over considerable tracts (e.g., in the Wheat Belt and Kalgoorlie areas), while the vast number of "lakes" in the interior are little more than saline flats akin to the widespread clay-pans. The lack of adequate fresh water in the interior south-west has been met by a vig orous policy of surface (rainfall) storage and reticulation. Chief amongst such schemes is the Gold-Fields Water-supply Scheme by which water derived from a catchment in the Darling ranges behind Perth is stored in the Mundaring reservoir (76o ac.; 4,65o million gal.) and conducted thence by means of a pipe-line with 8 pumping stations to a service reservoir (12,000,000 gal.) at Bullabulling 307 miles distant. Thence the water is reticulated by gravity to Kalgoorlie (44 m.) ; it is also supplied to 3o towns "en route," to mines, and to agricultural areas ( 500 extensions). (Total area covered: 16,000 sq.m. ; total length of mains [1926] : miles; total consumption: 1,161,000,00o gal. per ann.—railways, c. 8%; mines, 22%; "other," 70%. Capital cost, £3,642,000; revenue, £179,400; expenditure, L218, 950.) There is an extensive system of water-supply to towns (1926: 23 towns, pop. c. 14,000; gal., including rail ways) and to agricultural areas.