GLOSSARY OF IRRIGATION TKRMS. 489 



Siphon — A bent pipe or tube, or even a box, for drawing water 



by atmospheric pressure; also syphon. 

 Slope — The grade of a ditch. 

 Sluice — An artificial channel for carrying water, with gates or 



valves. 

 Spillway — A waste weir or overflow. 

 Standpipe — An elevated tap for draining water from a main ; 



a tower-like pipe at a reservoir into which water is pumped 



to give it a head. 

 Storm Water — That which falls in catchments during freshets. 

 Stmt — A compression brace in a framework, as a truss. 

 Subbing — Water percolating near the surface and utilized in 



subirrigation. 

 Subirrigation — Watering land through pipes or channels below 



the surface. 

 Subsidiary Canals — Those that are secondary. 

 Subsoiling — To break up ; to loosen the subsoil. 

 Sump — A shallow well or cistern. 

 Tail-Race — A wasteway from a canal. 

 Tamp — To pack with earth or other materials. 

 Target — An instrument used as a flag in directing surveyors. 

 Terreplein — The level fill or surface of earth made to connect 



with flumes, etc. 

 Tumbeam — A sort of treadmill device used in Oriental lands 



for raising water. 

 Tympanum — A large drum-wheel for raising water from a run- 

 ning stream. 

 Underflow — Currents of water below the earth's surface. 

 Warping — A method of retaining water by means of banks in 



overflows, as of tides along the ocean shore. 

 Waste Gate — An outlet for discharging water from a canal or 



storage pond. 

 Water Register — An instrument for measuring the flow of 



streams. 

 Water Right — A privilege ; the right to the possession and use 



of water for irrigating. 

 Water Witchery — Art of discovering the underground presence 



of water by aid of divining rods. 



