grading of silt

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• irrigation and drainage — ▪ agriculture Introduction  artificial application of water to land and artificial removal of excess water from land, respectively. Some land requires irrigation or drainage before it is possible to use it for any agricultural production; other… …   Universalium

• dam — dam1 /dam/, n., v., dammed, damming. n. 1. a barrier to obstruct the flow of water, esp. one of earth, masonry, etc., built across a stream or river. 2. a body of water confined by a dam. 3. any barrier resembling a dam. v.t. 4. to furnish with a …   Universalium

• Dam — /dam, dahm/, n. (Carl Peter) Henrik /kahrl pee ter hen rik/; Dan. /kahrddl pay teuhrdd hen rddik/, 1895 1976, Danish biochemist: Nobel prize for medicine 1943. * * * I Barrier built across a stream, river, or estuary to conserve water for such… …   Universalium

• tobacco — tobaccoless, adj. /teuh bak oh/, n., pl. tobaccos, tobaccoes. 1. any of several plants belonging to the genus Nicotiana, of the nightshade family, esp. one of those species, as N. tabacum, whose leaves are prepared for smoking or chewing or as… …   Universalium

• agricultural technology — Introduction       application of techniques to control the growth and harvesting of animal and vegetable products. Soil preparation       Mechanical processing of soil so that it is in the proper physical condition for planting is usually… …   Universalium

• Gravel road — A gravel road, as often found in rural areas and lesser developed nations. A …   Wikipedia

• Big Eddy Site — The Big Eddy Site (23CE426) is an archaeological site located in the southwestern portion of the U.S. state of Missouri, which was first excavated in 1997 and is now threatened due to erosion from the Sac River. Location and General… …   Wikipedia

• permafrost — /perr meuh frawst , frost /, n. (in arctic or subarctic regions) perennially frozen subsoil. Also called pergelisol. [1943; PERMA(NENT) + FROST] * * * Perennially frozen earth, with a temperature below 32 °F (0 °C) continuously for two years or… …   Universalium

• rock — rock1 rockless, adj. rocklike, adj. /rok/, n. 1. a large mass of stone forming a hill, cliff, promontory, or the like. 2. Geol. a. mineral matter of variable composition, consolidated or unconsolidated, assembled in masses or considerable… …   Universalium

• Rock — /rok/, n. a male given name. * * * I In geology, a naturally occurring and coherent aggregate of minerals. The three major classes of rock igneous, sedimentary, and metamorphic are based on the processes that formed them. These three classes are… …   Universalium

• tunnels and underground excavations — ▪ engineering Introduction        Great tunnels of the world Great tunnels of the worldhorizontal underground passageway produced by excavation or occasionally by nature s action in dissolving a soluble rock, such as limestone. A vertical opening …   Universalium