Water terms starting with F

203 terms

  1. Flood Loss Reduction Measures The strategy for reducing flood losses. There are four basic strategies. They are prevention, property protection, emergency services, and structural…
  2. Flood of Record The highest observed river stage or discharge at a given location during the period of record keeping. (Not necessarily the highest known stage.)
  3. Flood Plain A strip of relatively flat and normally dry land alongside a stream, river, or lake that is covered by water during a flood.
  4. Flood Plain Information Studies Reports usually prepared by the U.S. Army Corps of Engineers (USACE) following a survey of a flood-impacted community.
  5. Flood pool index Computed as the ratio of the flood control pool depth to the depth below the pool, multiplied by the percent of time the reservoir water surface will be…
  6. Flood Potential Outlook (ESF on AFOS) (FPO) An NWS outlook that is issued to alert the public of potentially heavy rainfall that could send area rivers and streams into flood or aggravate an…
  7. Flood Prevention Measures that are taken in order to keep flood problems from getting worse. Planning, land acquisition, river channel maintenance, wetlands protection…
  8. Flood Problems Problems and damages that occur during a flood as a result of human development and actions.
  9. Flood Profile A graph of elevation of the water surface of a river in flood, plotted as ordinate, against distance, measured in the downstream direction, plotted as…
  10. Flood Routing A process of determining progressively over time the amplitude of a flood wave as it moves past a dam or downstream to successive points along a river or…
  11. Flood severity Qualitative description of how severe a possible flood could be (High, Medium, Low) depending on failure modes (including rate of failure), flood…
  12. Flood severity understanding Understanding as to what degree flooding might affect the downstream population.
  13. Flood Stage An established gage height within a given river reach above which a rise in water surface level is defined as a flood.
  14. Flood Statement (FLS) A statement issued by the NWS to inform the public of flooding along major streams in which there is not a serious threat to life or property.
  15. Flood Warning (FLW) A release by the NWS to inform the public of flooding along larger streams in which there is a serious threat to life or property.
  16. Flood Wave A rise in streamflow to a crest and its subsequent recession caused by precipitation, snow melt, dam failure, or reservoir releases.
  17. Flooded Ice Ice which has been flooded by melt water or river water and is heavily loaded by water and wet snow.
  18. Floodproofing The process of protecting a building from flood damage on site. Floodproofing can be divided into wet and dry floodproofing.
  19. Floodwall A long, narrow concrete, or masonry embankment usually built to protect land from flooding.
  20. Floodway (1) A part of the flood plain, otherwise leveed, reserved for emergency diversion of water during floods.
  21. Flora Plants, especially those of a specific region, considered as a group.
  22. Flow Volume of water that passes a given point within a given period of time. See base flow, discharge, enhancement flow, instream flow requirements…
  23. Flow augmentation The release of water stored in a reservoir or other impoundment to increase the natural flow of a stream.
  24. Flow channel The portion of a flow net bounded by two adjacent flow lines.
  25. Flow curve The locus of points obtained from a standard liquid limit test and plotted on a graph representing moisture content as ordinate on an arithmetic scale and…
  26. Flow Duration Curve A cumulative frequency curve that shows the percentage of time that specified discharges are equaled or exceeded.
  27. Flow failure Failure in which a soil mass moves over relatively long distances in a fluidlike manner.
  28. Flow line The path that a particle of water follows in its course of seepage under laminar flow conditions.
  29. Flow net A graphical representation of flow lines and equipotential (piezometric) lines used in the study of seepage phenomena.
  30. Flow slide The failure of a sloped bank of soil in which the movement of the soil mass does not take place along a well-defined surface of sliding.
  31. Flowage Water that floods onto adjacent land.
  32. Flowage easement The right or easement to overflow, submerge, or flood certain lands; a right to prohibit building on certain floodways.
  33. Flowing Artesian Well A well drilled into a confined aquifer with enough hydraulic pressure for the water to flow to the surface without pumping.
  34. Fluctuating flows Water released from a dam that varies in volume with time.
  35. Fluctuating zone Area of a sandbar or vegetation zone that is within the range of fluctuating flow.
  36. Flume Shaped, open-channel flow sections that force flow to accelerate. Acceleration is produced by converging the sidewalls, raising the bottom, or a…
  37. Flushing A method used to clean water distribution lines by passing a large amount of water through the system.
  38. Fluvial Pertaining to a river. Fluvial sediments are deposited by rivers.
  39. Fly ash The fine particulate matter entrained in the flue gases of a combustion power plant.
  40. FONSI - finding of no significant impact.
  41. Food chain The chain of organisms in a community that produce food and consume it.
  42. Foot Twelve inches. One of a number of projections on a cylindrical drum of a tamping roller.
  43. Foot Pound The amount of work done in raising one pound one foot.
  44. Footing A sill under a foundation. Ground, in relation to its load bearing and friction qualities.
  45. Forage Small baitfish, crayfish and other creatures that bass or other predator fish eat.
  46. Forage fish Generally, small fish that produce prolifically and are consumed by predators.
  47. Forb A weed or a broad-leafed plant.
  48. Forced outage Unscheduled shut down of a generating unit or other facility for emergency or other unforeseen reasons.
  49. Ford A place where a road crosses a stream under water.
  50. Forebay The water behind (upstream) of the dam.
  51. Forebay (headrace) Impoundment immediately upstream from a dam or hydroelectric plant intake structure.
  52. Forecast Crest The highest elevation of river level, or stage, expected during a specified storm event.
  53. Forecast Point A location that represents an area (reach of a river), where a forecast is made available to the public.
  54. Forepole A plank driven ahead of a tunnel face to support the roof or wall during excavation. See horsehead.
  55. Foreshore That part of the shore between the ordinary high-and low-watermarks and generally crossed by the tide each day.
  56. Foresight A sighting on a point of unknown elevation from an instrument of known elevation.
  57. Forest Service (FS) The mission of the USDA Forest Service is to sustain the health, diversity, and productivity of the Nation's forests and grasslands to meet the needs of…
  58. Formation Any sedimentary, igneous, or metamorphic material represented as a unit in geology; generally called rock, but not necessarily meeting the definition of…
  59. Formulation process First phase performed by the Early Warning System design team, which includes an Early Warning System reliability, local capabilities assessment, and…
  60. Fossorial insects Insects that live in the soil.
  61. Foundation The supportive structure of a building.
  62. Foundation drains Tile or pipe for collecting seepage within a foundation.
  63. Foundation material (foundation soil) The upper part of the earth mass carrying the load of the structure.
  64. Foundation of Dam The material on which the dam structure is placed. Often modified to provide more favorable hydraulic characteristics. See "Cutoff".
  65. Foundation surface The surface of the upper part of the earth mass carrying the load of the structure.
  66. Foundation trench A trench built at and into the foundation of a dam and filled with clay or other impermeable substances to prevent water from seeping beneath the dam.
  67. Fountainhead The upper end of a confined-aquifer conduit, where it intersects the land surface.
  68. Fracture (frack'chur)a broken bone.
  69. Fracture (joint) Crack or break in rocks along which no movement has occurred.
  70. Fracture Zone An area which has a great number of fractures.
  71. Fracturing Deformation process whereby ice is permanently deformed, and fracture occurs.
  72. Frazil Ice Fine spicules, plates, or discoids of ice suspended in water. In rivers and lakes, frazil is formed in supercooled, turbulent water.
  73. Frazil Slush An agglomerate of loosely packed frazil which floats or accumulates under the ice cover.
  74. Free Ground Water Unconfined ground water whose upper boundary is a free water table.
  75. Freeboard Portion of the dam above spillway level to protect the dam against washout.
  76. Freeze-thaw damage Damage to concrete caused by extreme temperature variations as noted by random pattern cracking.
  77. Freezeout Deeply frozen over for long periods of time.
  78. Freezeup date Date on which the water body was first observed to be completely frozen over.
  79. Freezup jam Ice jam formed as frazil ice accumulates and thickens.
  80. French Drain A covered ditch containing a layer of fitted or loose stone or other pervious material.
  81. Frequency Curve A curve that expresses the relation between the frequency distribution plot, with the magnitude of the variables as abscissas and the number of…
  82. Frequency demand scheduling Method of irrigation scheduling similar to demand scheduling, but typically involves a fixed duration of the delivery, such as 24 hours.
  83. freshwater A term referring to bodies of water that do not have salt.
  84. Friction Resistance to motion when one body is sliding or tending to slide over another.
  85. Friction Head The energy lost from the movement of a fluid in a conduit (pipe) due to the disturbances created by the contact of the moving fluid with the surfaces of…
  86. FRO Fresno Office (Fresno, CA).
  87. Front end loader A tractor loader that both digs and dumps in front.
  88. Frost action Freezing and thawing of moisture in materials and the resultant effects on these materials and on structures of which they are a part of with which they…
  89. Frost heave The raising of a surface due to the accumulation of ice in the underlying soil or rock.
  90. Frost line The greatest depth to which ground may be expected to freeze.
  91. Froude number The ratio of inertial forces to gravitational forces in flow. It is also the ratio of the flow velocity to the velocity of a small gravity wave in the…
  92. Fry Immature fish from the time they hatch to the time they become fingerlings.
  93. FS - U.S. Forest Service, feasibility study, factor of safety.
  94. Fuel replacement energy Electric energy generated at a hydroelectric plant as a substitute for energy which would have been generated by a thermal electric plant.
  95. Fulcrum A pivot for a lever.
  96. Full gate Maximum gate position of a turbine for a particular head.
  97. Full hydraulic capacity The designed capacity of a pipe or conduit.
  98. Full irrigation service land Irrigable land now receiving, or to receive, its sole and generally adequate water supply through facilities which have been or are to be constructed by…
  99. Full pool Volume of water in a reservoir at normal water surface. The reservoir level that would be attained when the reservoir is fully utilized for all project…
  100. Furrow A natural or man-made narrow depression in the earth's surface. A narrow trenchlike plowed depression in the earth surface to keep surface water away from…