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- Encyclopaedia Of Groundwater Hydrology & Hydraulics...
Encyclopaedia Of Groundwater Hydrology & Hydraulics : Engineering , Planning & Management ( 4 Volumes Set )
The hydrologic cycle is a constant movement of water above, on, and below the earth’s surface. It is a cycle that replenishes ground water supplies. It begins as water vaporizes into the atmosphere from vegetation, soil, lakes, rivers, snowfields and oceans—a process called evapotranspiration. As the water vapour rises it condenses to form clouds that return water to the land through precipitation: rain, snow, or hail. Precipitation falls on the earth and either percolates into the soil or flows across the ground. Usually it does both. When precipitation percolates into the soil it is called infiltration; when it flows across the ground it is called surface runoff. The amount of precipitation that infiltrates, versus the amount that flows across the surface, varies depending on factors such as the amount of water already in the soil, soil composition, vegetation cover and degree of slope. Surface runoff eventually reaches a stream or other surface water body where it is again evaporated into the atmosphere. Infiltration, however, moves under the force of gravity through the soil. If soils are dry, water is absorbed by the soil until it is thoroughly wetted. Then excess infiltration begins to move slowly downward to the water table. Once it reaches the water table, it is called groundwater. Groundwater continues to move downward and laterally through the subsurface. Eventually it discharges through hillside springs or seeps into streams, lakes, and the ocean where it is again evaporated to perpetuate the cycle. The unsaturated zone is almost always underlain by a second zone in which all voids are full of water. This zone is defined as the saturated zone. Water in the saturated zone is referred to as groundwater and is the only subsurface water available to supply wells and springs. It is intended that the book will prove to be an essential reference guide that provides comprehensive knowledge to the students, researchers and professionals of civil and environmental engineering.
AUTOR: Dixon, Samuel
EDITORA: Auris Reference
DISPONIBILIDADE DO PRODUTO: Sob Encomenda - Até 40 dias ( Importação )