GLOSSARY OF IRRIGATION TERMS. 305 



Catchment Extent of country that may be utilized in 



drawing water to a certain point, as a reservoir; also 



catchment area. 

 Check An impediment placed in a lateral to divert water 



out upon the land. 



Conduit An aqueduct for passing water ; a tube or pipe. 

 Contour The high level line describing the course of a 



canal. 

 Crown Arch An arched plate serving as a keystone in a 



masonry curved dam. 

 Cylinder An enlarged mechanism for a piston at the bottom 



of a pump in a well. 

 Dam A barrier to confine the flow of a stream to raise its 



level ; an embankment of a reservoir. 

 Detritus Disintegrated material of any kind flowing in a 



ditch ; silt or alluvial deposit. 

 Dike An embankment for holding water. 

 Ditch An artificial water course, one somewhat smaller than 



a canal. 

 Ditching Machine An implement for excavating canals, 



etc. 



Diversion Dam A structure in a natural stream for divert- 

 ing the water into a canal. 

 Division Box A contrivance for dividing or apportioning 



water to consumers. 



Drop Box An arrangement in a canal for lowering or re- 

 ducing the grade. 

 Duty of Water Service required of water in supplying 



land ; the tax to which water is put in irrigating. 

 Evaporation The loss of water by vaporizing. 

 Fellah An Egyptian laborer, cultivator or irrigator. 

 Filament The center course of a current in a stream 

 Fill-Bank Material used in constructing embankments. 

 Filtration Act of filtering, as water through soil. 

 Flights A continuous series of lifting buckets or plates in 



a water elevator. 

 Float An object thrown into a stream to calculate water 



velocity ; a water-wheel paddle. 

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