step drawdown test . A type of aquifer test in which the water level in a pumped well is measured while the well is pumped at a constant rate for a given period of time; the pumping rate is successively increased for each of several time intervals, the water level is measured during each interval, and drawdown is calculated for each pumping rate. The derived relationship between drawdown and pumping rate can be used to estimate aquifer properties, the practical yield of the pumping well, and the appropriate depth setting of the pump in a production well.
GeoWord of the Day
The GeoWord of the Day is a free service of the American Geosciences Institute. All of the terms and definitions are from the Glossary of Geology, 5th Edition Revised.
medenbachite . A yellow to brownish-yellow triclinic mineral: Bi2Fe3+(Cu,Fe2+)O(AsO4)2(OH)3.
hurricane (hur'-ri-cane). A tropical cyclone, esp. in the North Atlantic and eastern North Pacific basins, in which the sustained near-surface wind speed equals or exceeds 64 knots (73 mph). See also: typhoon.
wodanite (wo'-da-nite). A variety of biotite containing titanium.
minipermeametry . Measurement of permeability of flat rock faces at the millimeter scale (Goggin, 1993).
auto-biotope . The total of all environments which one and the same taxonomic unit characteristically inhabits (van Morkhoven, 1966, p.306).
upper plane bed . A bed configuration under a unidirectional current that is characterized by a flat, almost featureless surface over which sediment transport is intense, both in suspension and on the bed. Some authors report very low, downstream migrating bed forms as being characteristic of this bed configuration (e.g., Best and Bridge, 1992). Current lineations are common on upper plane bed surfaces. Syn: upper flow regime plane bed; upper stage plane bed.
Tuttle lamellae (Tut'-tle). Planes of inclusions in quartz, oriented randomly rather than with reference to the enclosing crystal. Cf: Boehm lamellae.
strontianite (stron'-ti-an-ite''). A pale green, white, gray, or yellowish orthorhombic mineral of the aragonite group: SrCO3 .
catenary ripple . "A ripple is described as catenary if the trace of its crestline has the pattern of a chain of catenary waves, such that the more pointed segments of the crestline face downcurrent" (Allen, 1968, p.62-63). It differs from a lunate ripple in having lesser curvature of the crestline. Catenary ripples may be in or out of phase with the ripples immediately upstream or downstream.
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