Water — page 15 of 31

3,083 terms

Water terms

  1. Gravity arch dam A dam designed to combine load resisting features of both a gravity and arch type dam.
  2. Gravity Dam A dam constructed of concrete and/or masonry which relies on its weight and internal strength for stability.
  3. Gravity irrigation Irrigation method that applies irrigation water to fields by letting it flow from a higher level supply canal through ditches or furrows to fields at a…
  4. Gray water Wastewater other than sewage, such as sink and bath drainage or washing machine discharge.
  5. Grid A common term referring to an electricity transmission and distribution system.
  6. Grid operator An entity that oversees the delivery of electricity over the grid to the customer, ensuring reliability and safety.
  7. Grizzly (grizzlie) A coarse screen used to remove oversize pieces from earth or blasted rock. A gate or closure on a chute.
  8. Groin The area where the thigh meets the abdomen.
  9. Gross crop value This value is the sum of annual receipts from sale of crops produced. Production of crops, such as pasture and hay which normally are consumed on the farm…
  10. Gross Generation The total amount of electricity produced by a power plant.
  11. Ground motion A general term including all aspects of ground motion, namely particle acceleration, velocity, or displacement, from an earthquake or other energy source.
  12. Ground motion parameters Numerical values representing vibratory ground motion, such as particle acceleration, velocity, and displacement, frequency content, predominant period…
  13. Ground receive sites A satellite dish and associated computer which receives signals from the GOES satellite, decodes the information, and transmits it to a another site for…
  14. Ground Water Water that flows or seeps downward and saturates soil or rock, supplying springs and wells.
  15. Ground Water Divide A line on a water table where on either side of which the water table slopes downward.
  16. Ground Water Flow Streamflow which results from precipitation that infiltrates into the soil and eventually moves through the soil to the stream channel.
  17. Ground Water Hydrology The branch of hydrology that specializes in ground water; its occurrence and movements; its replenishment and depletion; the properties of rocks that…
  18. Ground Water Mining Pumping ground water from a basin where the safe yield is very small, thereby extracting ground water which had accumulated over a long period of time.
  19. Ground water mining (overdraft) Pumping of ground water for irrigation or other uses, at rates faster than the rate at which the ground water is being recharged.
  20. Ground Water Outflow That part of the discharge from a drainage basin that occurs through the ground water.
  21. Ground Water Overdraft Pumpage of ground water in excess of safe yield.
  22. Ground water recharge The flow to ground water storage from precipitation, inflitration from streams, and other sources of water.
  23. Ground Water Runoff That part of the runoff which has passed into the ground, has become ground water, and has been discharged into a stream channel as spring, or seepage…
  24. Ground water table The upper boundary of ground water where water pressure is equal to atmospheric pressure, i.e.
  25. Ground-fault circuit interrupter (GFCI) An electrical device designed to protect people (not equipment) from electrical shock.
  26. Grounded ice Ice that has run aground or is contact with the ground underneath it.
  27. Grout A fluid mixture of cement and water or sand, cement, and water used to seal joints and cracks in a rock foundation.
  28. Grout Blanket An area of the foundation systematically grouted to a uniform shallow depth.
  29. Grout cap A concrete pad or wall constructed to facilitate subsequent pressure grouting of the grout curtain beneath the grout cap.
  30. Grout Curtain A barrier produced by injecting grout into a vertical zone, usually narrow (horizontally), and in the foundation to reduce seepage under a dam.
  31. Grout Curtain (Grout Cutoff) A vertical zone, usually thin, in the foundation into which grout is injected to reduce seepage beneath a dam.
  32. Grouting Filling cracks and crevices with a cement mixture.
  33. Growing Season The period, often the frost-free period, during which the climate is such that crops can be produced.
  34. Grubbing See Clearing and grubbing
  35. Guard gate (emergency) The first gate in a series of flow controls, remaining open while downstream gates or valves are operating.
  36. Gullying Small-scale stream erosion.
  37. Habitat The natural environment where people, animals and plants live. In an aquatic environment, it includes the water, topography, structure and cover present…
  38. Habitat Areas of Particular Concern (HAPC) (HAPC) A habitat area designated by a Fishery Management Council under the Magnuson-Stevens Fishery Conservation and Management Act of 1976 to help focus…
  39. Halophytic Salt-loving. Plants that thrive in soils that contain salt and/or sodium. A plant that grows in salty or alkaline soil.
  40. Hanger A support for pipe.
  41. Hanging (ice) dam A mass of ice composed mainly of frazil or broken ice deposited underneath an ice cover in a region of low flow velocity.
  42. Hard water Water may be considered hard if it has a hardness greater than the typical hardness of water from the region.
  43. Hardness A characteristic of water determined by the levels of calcium and magnesium. Water hardness is largely the result of geological formations of the water…
  44. Hardpan A dense, often impermeable soil horizon cemented with silica, iron oxides, calcium carbonate, or organic matter.
  45. Harrow An agricultural tool that loosens and works the ground surface.
  46. Harvest In a recreational fishery, refers to numbers of fish that are caught and kept. See catch.
  47. Hatchery A facility where fish and raised for stocking.
  48. Haul distance The distance measured along the center line or most direct practical route between the center of the mass of excavation and the center of mass of the fill…
  49. Haunches (haunch) The outside areas between the springline and the bottom of a pipe. In pipe, the sides of the lower third of the circumference.
  50. Hazard Something (e.g., a dam) that creates the potential for adverse consequences such as loss of life (LOL), property damage, and adverse social and…
  51. Hazard classification The rating for a dam based on the potential consequences of failure. The rating is based on potential for loss of life and damage to property that failure…
  52. Hazardous materials Materials that pose the potential for grave, immediate, future, and genetic injury and illness when handled without proper equipment and precautions.
  53. Hazardous substances Element or compound other than oil which when discharged into the environment, in any quantity, presents an imminent or substantial threat to public…
  54. Hazardous Waste Indicators Indicators that may signal the presence of hazardous materials include stressed vegetation or unusual lack of vegetation; dead or sick domestic stock…
  55. Hazardous waste sites Any spill, authorized or unauthorized dumping, abandoned, or inactive waste disposal sites containing or suspected of containing hazardous materials.
  56. HDRAIN An Hourly Digital Rainfall Product of the WSR-88D.
  57. Head The upper horizontal part of a window frame or window opening.
  58. Head Loss The energy lost from a flowing fluid due to friction, transitions, bends, etc.
  59. Head Race A channel which directs water to a water wheel; a forebay.
  60. Header A masonry wall unit of brick which is laid so that its short end is exposed.
  61. Heading In a tunnel, a digging face and its work area.
  62. Headrace. See forebay.
  63. Headwall An upstream wall.
  64. Headward Erosion Erosion which occurs in the upstream end of the valley of a stream, causing it to lengthen its course in such a direction.
  65. Headwater (1) The source and upper reaches of a stream; also the upper reaches of a reservoir; (2) the water upstream from a structure or point on a stream; (3) the…
  66. Headwater Advisory Program (ADVIS) (ADVIS) A Program which uses the Antecedent Precipitation Index (API) method of estimating runoff, unit hydrograph theory and stage-discharge ratings to produce…
  67. Headwater Advisory Table A table developed by a River Forecast Center for a Headwater Guidance Point; a pre-computed matrix of values allows a forecaster to ascertain an…
  68. Headwater Basin A basin at the headwaters of a river. All discharge of the river at this point is developed within the basin.
  69. Headwaters Streams at the source of a river.
  70. Heap The soil carried above the sides of a body or bucket.
  71. Heave The upward movement of land surfaces or structures due to subsurface expansion of soil or rock, or vertical faulting of rock.
  72. Hectare An area equal to 2.47 acres. There are 100 hectares in 1 square kilometer.
  73. Heel of Dam The junction of the upstream face of a concrete gravity dam or arch dam with the ground surface.
  74. Height of dam. See hydraulic height or structural height.
  75. Helical Spiral.
  76. Herbicide A chemical that kills plants.
  77. Herbivore Animal that feeds on plants.
  78. Herpetofauna Amphibian and reptile species including frogs, toads, salamanders, turtles, lizards, and snakes.
  79. Hertz (Hz) (Hz) The unit of measurement of frequency, equivalent to one cycle per second.
  80. High dam A dam over 300 feet high. See low dam and medium-height dam.
  81. High hazard A downstream hazard classification for dams in which more than 6 lives would be in jeopardy and excessive economic loss (urban area including extensive…
  82. High-pressure gate A gate consisting of a rectangular leaf encased in a body and bonnet and equipped with a hydraulic hoist for moving the gate leaf.
  83. Hinge Crack Crack caused by significant changes in water level.
  84. HOE A shovel that digs by pulling a broom-and-stick-mounted bucket toward itself.
  85. Hogback Ridge formed by erosion of resistant, steeply inclined sedimentary layers.
  86. Hoist The mechanism by which a bucket or blade is lifted, or the process of lifting it.
  87. Hollow gravity dam (cellular gravity dam) A dam which has the outward appearance of a gravity dam but is of hollow construction.
  88. Hollow-jet valve A valve having a closing member that moves upstream to shut off the flow. The hollow-jet valve discharges a hollow or annular jet dispersed over a wide…
  89. Homogeneous earthfill dam An embankment dam construction throughout of more or less uniform earth materials, except for possible inclusion of internal drains or blanket drains.
  90. Homogeneous Rolled Earth Dam An embankment dam constructed of similar earth material throughout, except for possible inclusion of internal drains or drainage blankets; distinguished…
  91. Hopper A storage bin or a funnel that is loaded from the top, and discharges through a door or chute in the bottom.
  92. Hornblende Black blade-like mineral common in igneous and metamorphic rocks.
  93. Hornfels Fine-grained, gray-green metamorphic rock produced by "baking" of sedimentary rocks by an igneous intrusion in which sedimentary features may still be…
  94. Horsehead (false set) A temporary support for forepoles used in tunneling soft ground.
  95. Horsepower (hp) (hp) A unit of rate of operation. Electrical hp: a measure of time rate of mechanical energy output; usually applied to electric motors as the maximum output…
  96. Horst An elongated crustal block that is relatively raised between two parallel normal faults or grabens. See also Half-graben
  97. Howell Bunger valve. See fixed cone valve.
  98. Hub A network device that connects multiple computers/peripherals together and allows them to share data.
  99. Human environment Natural and physical environment and the relationship of people with that environment, including all combinations of physical, biological, cultural…
  100. Hummock A hillock of broken ice which has been forced upward by pressure.

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