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Springs,city, now part of EkurhuleniEkurhuleni,
metropolitan municipality (2011 pop. 3,178,470), Gauteng prov., NE South Africa. Ekurhuleni largely encompasses the East Rand region of Gauteng. Germiston is the municipal seat; other communities include Katlehong, Tembisa, Boksburg, Vosloorus, Tsakane, Daveyton,
..... Click the link for more information. metropolitan municipality, Gauteng prov., NE South Africa. It is an industrial center of the WitwatersrandWitwatersrand
[Afrik.,=white water ridge] or the Rand,
region, Gauteng prov. (formerly a part of Transvaal), South Africa. The area, which forms the watershed between the Vaal and Olifants rivers, is c.
..... Click the link for more information. , a gold- and uranium-mining region. Manufacturing has replaced mining in economic importance and includes processed metals, chemicals, paper, and foodstuffs. Springs began to develop after the start (1885) of coal mining nearby.
(sources of underground water), natural outlets of underground water to the surface (on land or under water). Factors that may cause springs to form include the intersection of water-bearing horizons by negative formations of present-day relief (for example, river valleys, ravines, gullies, and lake basins), geological-structure characteristics of the terrain (the presence of cracks, zones of tectonic dislocations, contacts between igneous and sedimentary rocks), and different filtration capacities of water-bearing rocks.
Springs may be classified in several different ways. According to the classification proposed by the Soviet hydrogeologist A. M. Ovchinnikov, three groups of springs are identified, depending on whether they are fed by vadose water, groundwater, or artesian water. Springs in the first group, which are usually in the aeration zone, have sharp variations in flow (sometimes completely drying up) and in the chemical composition and temperature of the water. Springs fed by groundwater show great constancy over time but are also subject to seasonal variations in flow, composition, and temperature. Groundwater springs are subdivided into depression springs (which appear as the result of deepening of river drainage and tapping of underground reservoirs), contact springs (confined to contacts between rocks of different water-permeability), and overflow springs (usually ascending, related to facies variability in strata or to tectonic dislocations). Artesian springs are distinguished by great constancy in regime and are confined to discharge areas of artesian basins.
In terms of regime all springs may be subdivided into those that function perennially, seasonally, or rhythmically. The study of the regime of springs is very important if they are to be used for drinking water or therapeutic water supply. In terms of hydrodynamic properties, springs may be divided into gravity springs, fed by unpressured water, and ascension springs, fed by artesian water. Springs that are confined to porous rocks are distributed more or less evenly in places where a water-bearing horizon comes out on the surface; springs in fissured rocks are located in places where the cracks intersect the earth’s surface. Springs in karst regions typically have great variations in regime, related to the amount of atmospheric precipitation. The temperature of water in springs depends on the depth of the underground water, the nature of the incurrent canals, the geographic and hypsometric position of the springs, and the temperature regime of the underground water. In permafrost regions, springs with water temperatures near 0°C are found; hot springs, often with intermittent regimes, occur in areas of young volcanic activity.
The chemical and gas composition of spring water is extremely varied and is determined primarily by the composition of the underground water being discharged and by the overall hydrogeological conditions of the region. Adapting the natural outlets of water from various springs to man’s use is called capping.
REFERENCESAl’tovskii, M. E. “Klassifikatsiia rodnikov.” In the collection Voprosy gidrogeologii i inzhenernoi geologii, no. 19. Moscow, 1961.
Klimentov, P. P. Obshchaia gidrogeologiia, 3rd ed. Moscow, 1971.
Ovchinnikov, A. M. Obshchaia gidrogeologiia, 2nd ed. Moscow, 1954.
I. S. ZEKTSER
a city in the Republic of South Africa, in Transvaal Province. Population, 104,000 (1970, excluding suburbs). Railroad junction. Springs is a gold-mining center in the Witwatersrand region. Industries include metalworking and the production of sheet glass, mining and printing equipment, and electric motors.