Transcription of Estimating Water Flow From Pipes
1 Cooperative Extension ServiceCollege of Agriculture and Home EconomicsNEWMEXICOSTAEUNIVERSITYTE stimating WaterFlow From PipesGuide Hohn, Extension Agricultural EngineerThis publication is scheduled to be updated and reissued 10 recent years, there have been increased demandsupon our limited Water supply by industry, cities andtowns, recreation, and agriculture. So irrigators should usethe available Water supply more wisely than ever management takes the guesswork out of the ap-plication of irrigation Water to the land. Times andamounts of Water applied are just as important as the timesand amounts of seed and fertilizer management involves measuring Water at de-livery points to determine exact amounts going to the standard term for rate of flow of irrigation Water iscubic feet per second (cfs). A cubic foot per second of wa-ter is flowing when a cubic foot volume of Water (equal toone foot wide, one foot long, and one foot high) passes agiven point every cubic foot of Water equals: Approximately 405 gallons per minute (gpm).
2 Approximately 1 acre-inch per hour. Approximately 1 acre-foot per 12 hours. Approximately 2 acre-feet per 24 acre-inch is the volume of Water required to coveran acre of land one inch deep. An acre-foot is the volumeof Water required to cover an acre one foot following tables will be helpful to the irrigator indetermining the amount of Water being applied to the landwith nothing more than a carpenter s rule: pipe sizeHorizontal distance X InsideAreadiameter(Sq. In.)12"14"16" 18"20"22"24"26"28"30"32"34"36"2" " " " " " " " " " " " AX Where: A = Cross-sectional area of discharge pipe in square inches X = Horizontal distances in inches Y = Vertical distances in inchesQ=DISCHARGE FROM Pipes FLOWING FULLIn Gallons Per MinutewithVertical Drop Y = 13 Inches Guide A-104 Page 2AN APPROXIMATE METHOD OF ESTIMATINGDISCHARGE FROM Pipes FLOWINGPARTIALLY FULLRate of flow in gallons per minuteYInside diameter of pipe - D in FLOW FROMVERTICAL pipe OR CASINGThe approximate flow from vertical Pipes or casings canbe determined by measuring the maximum height(h) ininches to which the Water jet rises above the pipe , and in-side diameter of the pipe (d) in flow in gallons per minute is given in the followingtable for different sizes of standard pipe and for differentheights of the Water A-104 Page 3 NOMINAL DIAMETER (D) OF STANDARD pipe (INCHES)(Inches) (H)
3 For other pipe sizes and heights of jets. Use the formulae:Gal. per min. = CD2 HCu. ft. per sec. = CD2 HWhereD = inside pipe diameter in = jet height in = a constant varying from to for Pipes of 2 to 6 inches in diameter and heights of 6 to 224 A-104 Page 4 Reprinted October 1997 Las Cruces, NM5 CNew Mexico State University is an equal opportunity/affirmative action employer and educator. NMSU and the Department of Agriculturecooperating.
