page_title: Tainter gate
hierarchical_section_title: Tainter gate
caption_attribution_description: English: Tainter gate at McAlpine Dam (one of 9 such gates which regulate flow of water through dam), Louisville, Kentucky
context_page_description: The Tainter gate is a type of radial arm floodgate used in dams and canal locks to control water flow. It is named for Wisconsin structural engineer Jeremiah Burnham Tainter.
  A side view of a Tainter gate resembles a slice of pie with the curved part of the piece facing the source or upper pool of water and the tip pointing toward the destination or lower pool. The curved face or skinplate of the gate takes the form of a wedge section of cylinder. The straight sides of the pie shape, the trunnion arms, extend back from each end of the cylinder section and meet at a trunnion which serves as a pivot point when the gate rotates.
  Pressure forces on a submerged body act perpendicular to the body's surface. The design of the Tainter gate results in every pressure force acting through the centre of the imaginary circle of which the gate is a section, so that all resulting pressure force acts through the pivot point of the gate, making construction and design easier.
  When a Tainter gate is closed, water bears on the convex side. When the gate is rotated, the rush of water passing under the gate helps to open and close the gate.
context_section_description: The Tainter gate is a type of radial arm floodgate used in dams and canal locks to control water flow.  It is named for Wisconsin structural engineer Jeremiah Burnham Tainter. 
  A side view of a Tainter gate resembles a slice of pie with the curved part of the piece facing the source or upper pool of water and the tip pointing toward the destination or lower pool. The curved face or skinplate of the gate takes the form of a wedge section of cylinder.  The straight sides of the pie shape, the trunnion arms, extend back from each end of the cylinder section and meet at a trunnion which serves as a pivot point when the gate rotates.
  Pressure forces on a submerged body act perpendicular to the body's surface.  The design of the Tainter gate results in every pressure force acting through the centre of the imaginary circle of which the gate is a section, so that all resulting pressure force acts through the pivot point of the gate, making construction and design easier.
  When a Tainter gate is closed, water bears on the convex (upstream) side. When the gate is rotated, the rush of water passing under the gate helps to open and close the gate. The rounded face, long radial arms and trunnion bearings allow it to close with less effort than a flat gate. Tainter gates are usually controlled from above with a chain/gearbox/electric motor assembly.
  A critical factor in Tainter gate design is the amount of stress transferred from the skinplate through the radial arms and to the trunnion, with calculations pertaining to the resulting friction encountered when raising or lowering the gate. Some older systems have had to be modified to allow for frictional forces which the original design did not anticipate.
  The Tainter gate is used in water control dams and locks worldwide.  The Upper Mississippi River basin alone has 321 Tainter gates, and the Columbia River basin has 195. A Tainter gate is also used to divert the flow of water to San Fernando Power Plant on the Los Angeles Aqueduct. 
  The Tainter gate was invented in 1886 by Tainter, an employee of the giant lumber firm, Knapp, Stout and Co. Company, for use on the company's dam on the Red Cedar River forming Lake Menomin in Menomonie, Wisconsin.
caption: Tainter gate at McAlpine Dam, Ohio River, Louisville, Kentucky
exif: {"Image ImageDescription": "Looking SE from Falls of the Ohio:\r\nMiddle gate of 5 upper gates at McAlpine Dam.\r\nThese gates are called Tainter gates after their designer, Jeremiah Burnham Tainter (1836-1920).\r\nEach gate is 100 feet wide and 22 feet high.\r\nWhen water is released from the upstream pool, the gate is raised by cables connected to electric motors (not visible here) at the top of the structure. The \r\r\ngate pivots on the arms on either side, allowing the water to flow underneath. As seen here, a small amount of water flows under the gates even when they are \r\r\nclosed.\r\nIf a gate fails or needs work, maintenance bulkheads, one of which can be seen near top of image, can be lowered to block the water flow.\r\n\r\nThis section of dam is parallel to and just upstream from the Conrail (Fourteenth Street) Bridge.\r\n\r\nOhio River mile 605\r\nLouisville, Kentucky\r\n[Although this area is reached via Clarksville, Indiana, it is part of Kentucky, which owns the river to the low water line of the Indiana bank.]\r\n14-Nov-1998\r\nFile # 98k058\r\n_____________\r\n\r\nscanned from 6x9 cm Kodak PRN-2 (Pro 100) color negative\r\n\r\nEpson V500 scanner; Vuescan software\r\nscanned at 3200 dpi and reduced to 1600 dpi on output\r\n48-bit color; sRGB color profile\r\n\"restore fading\" filter\r\nmedium ICE\r\n\"white balance\" setting\r\nBlack point 0%\r\nWhite point 0.1%\r\ncurve low 0.25\r\ncurve high 0.75\r\nbrightness 1\r\n___________________\r\n\r\nIncreased HSL saturation 5%\r\nFilter: remove some red\r\nColor-correct: remove some blue\r\nFull range\r\nIncreased midtone contrast via brightness curve\r\nIncreased saturation 7%\r\nReduce to 2400 pixels high\r\nUSM 1, 3, 35%\r\nJPEG quality 95", "Image Make": "Epson", "Image Model": "PerfectionV500", "Image Software": "Picture Window Pro 64  v6.0.10", "Image Artist": "William Alden III", "Image Copyright": "William Alden III"}