Water Gap 



A narrow valley or gorge in a ridge of mountains or 

 hills, eroded by a stream, e.g., the Delaware Water Gap. 



Water-holding Capacity 



The amount of water, stated as the percentage of oven-dry 

 soil, that is retained by the soil after the gravitational water 

 has drained off. cf. Field capacity. 



Waterlogged 



The condition of a soil in which all the pore spaces are 

 filled with water. 



Water Requirement 



The ratio of the number of units of water absorbed by 

 a plant during the growing season to the number of units 

 of dry matter produced by the plant during the same time, 

 cf. Transpiration coefficient. 



Watershed 



(1) The total area of land above a given point on a 

 waterway that contributes run-off water to the flow at that 

 point. (2) A major subdivision of a drainage basin. 



Waterspout 



A tornado-like vortex and cloud occurring over a body 

 of water. 



Water Spreading 



The application by means of stream diversion or other- 

 wise of water over the land in order to increase the soil 

 moisture supply for the growth of plants or to store it under- 

 ground for subsequent withdrawal by pumping. 



Water Table 



The upper surface of the free ground water in a zone 

 of saturation, except where it is separated by an underlying 

 body of ground water by unsaturated material. 



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