Water — page 13 of 31

3,083 terms

Water terms

  1. Flash Flood Statement (FFS) (FFS) A statement by the NWS which provides follow-up information on flash flood watches and warnings.
  2. Flash Flood Table A table of pre-computed forecast crest stage values for small streams for a variety of antecedent moisture conditions and rain amounts.
  3. Flash Flood Warning Flash flooding has been reported or is imminent.
  4. Flash Flood Warning (FFW) (FFW) A warning by the NWS issued to warn of flash flooding that is imminent or occurring.
  5. Flash Flood Watch Flash flooding is possible within the designated watch area.
  6. Flash Flood Watch (FFA) (FFA) A statement by the NWS that alerts communities to the possibility of flash flooding in specified areas.
  7. Flashboards Temporary barriers, consisting of either timber, concrete or steel, anchored to the crest of a spillway as a means of increasing the reservoir storage.
  8. Flat slab or slab and buttress dam A buttress dam with buttresses which support the flat slab of reinforced concrete which forms the upstream face.
  9. Flatirons Triangular-shaped landforms along mountain ranges formed by erosion of steeply inclined rock layers or hogbacks.
  10. Fleet angle The angle between the position of a rope or cable at the extreme end wrap on a drum and a line drawn perpendicular to the axis of the drum.
  11. Flexible pipe Pipe designed to transmit the backfill load to the soil at the sides of the pipe.
  12. Fling Refers to a near field long period pulse from a strong ground motion resulting in a unidirectional ground heave after rupture.
  13. Flip bucket An energy dissipator located at the downstream end of a spillway and shaped so that water flowing at a high velocity is deflected upwards in a trajectory…
  14. Float Recording Precipitation gage A rain gage where the rise of a float within the instrument with increasing rainfall is recorded.
  15. Floatable days The number of days during the recreation season on which it is safe to allow floating activities on recreation facilities.
  16. Floatable flows River flows which make rafting and other floating recreation possible.
  17. Floc Loose, open-structured mass formed in a suspension by the aggregation of minute particles.
  18. Flocculation The process of forming flocs. A step in water filtration in which alum is added to cause particles to clump together.
  19. Floe An accumulation of frazil flocs (also known as a "pan") or a single piece of broken ice.
  20. Flood A general and temporary condition of partial or complete inundation of two or more acres of normally dry land area or of two or more properties (at least…
  21. Flood boundary Line drawn or outer edge of colored (inundation) area on an inundation map to show the limit of flooding.
  22. Flood control capacity Reservoir capacity assigned to the sole purpose of regulating flood inflows to reduce flood damage downstream. See exclusive flood control capacity.
  23. Flood control pool (flood pool) Reservoir volume above active conservation capacity and joint use capacity that is reserved for flood runoff and then evacuated as soon as possible to…
  24. Flood Control Storage Storage of water in reservoirs to abate flood damage.
  25. Flood Crest The maximum height of a flood wave as it passes a location.
  26. Flood frequency Refers to the probability (in percent) that a flood will occur in a given year.
  27. Flood Frequency Curve (1) A graph showing the number of times per year on the average, plotted as abscissa, that floods of magnitude, indicated by the ordinate, are equaled or…
  28. Flood Gate A gate to control flood releases from a reservoir.
  29. Flood hydrograph A graph showing, for a given point on a stream, the discharge, height, or other characteristic of a flood with respect to time.
  30. Flood irrigation Water is pumped or brought to the fields and is allowed to flow along the ground among the crops.
  31. Flood Loss Reduction Measures The strategy for reducing flood losses. There are four basic strategies. They are prevention, property protection, emergency services, and structural…
  32. 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.)
  33. 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.
  34. Flood Plain Information Studies Reports usually prepared by the U.S. Army Corps of Engineers (USACE) following a survey of a flood-impacted community.
  35. 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…
  36. 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…
  37. Flood Prevention Measures that are taken in order to keep flood problems from getting worse. Planning, land acquisition, river channel maintenance, wetlands protection…
  38. Flood Problems Problems and damages that occur during a flood as a result of human development and actions.
  39. 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…
  40. 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…
  41. Flood severity Qualitative description of how severe a possible flood could be (High, Medium, Low) depending on failure modes (including rate of failure), flood…
  42. Flood severity understanding Understanding as to what degree flooding might affect the downstream population.
  43. Flood Stage An established gage height within a given river reach above which a rise in water surface level is defined as a flood.
  44. Flood Statement (FLS) (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.
  45. Flood Warning (FLW) (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.
  46. Flood Wave A rise in streamflow to a crest and its subsequent recession caused by precipitation, snow melt, dam failure, or reservoir releases.
  47. Flooded Ice Ice which has been flooded by melt water or river water and is heavily loaded by water and wet snow.
  48. Floodproofing The process of protecting a building from flood damage on site. Floodproofing can be divided into wet and dry floodproofing.
  49. Floodwall A long, narrow concrete, or masonry embankment usually built to protect land from flooding.
  50. Floodway (1) A part of the flood plain, otherwise leveed, reserved for emergency diversion of water during floods.
  51. Flora Plants, especially those of a specific region, considered as a group.
  52. Flow Volume of water that passes a given point within a given period of time. See base flow, discharge, enhancement flow, instream flow requirements…
  53. Flow augmentation The release of water stored in a reservoir or other impoundment to increase the natural flow of a stream.
  54. Flow channel The portion of a flow net bounded by two adjacent flow lines.
  55. 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…
  56. Flow Duration Curve A cumulative frequency curve that shows the percentage of time that specified discharges are equaled or exceeded.
  57. Flow failure Failure in which a soil mass moves over relatively long distances in a fluidlike manner.
  58. Flow line The path that a particle of water follows in its course of seepage under laminar flow conditions.
  59. Flow net A graphical representation of flow lines and equipotential (piezometric) lines used in the study of seepage phenomena.
  60. 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.
  61. Flowage Water that floods onto adjacent land.
  62. Flowage easement The right or easement to overflow, submerge, or flood certain lands; a right to prohibit building on certain floodways.
  63. Flowing Artesian Well A well drilled into a confined aquifer with enough hydraulic pressure for the water to flow to the surface without pumping.
  64. Fluctuating flows Water released from a dam that varies in volume with time.
  65. Fluctuating zone Area of a sandbar or vegetation zone that is within the range of fluctuating flow.
  66. Flume Shaped, open-channel flow sections that force flow to accelerate. Acceleration is produced by converging the sidewalls, raising the bottom, or a…
  67. Flushing A method used to clean water distribution lines by passing a large amount of water through the system.
  68. Fluvial Pertaining to a river. Fluvial sediments are deposited by rivers.
  69. Fly ash The fine particulate matter entrained in the flue gases of a combustion power plant.
  70. FONSI - finding of no significant impact.
  71. Food chain The chain of organisms in a community that produce food and consume it.
  72. Foot Twelve inches. One of a number of projections on a cylindrical drum of a tamping roller.
  73. Foot Pound The amount of work done in raising one pound one foot.
  74. Footing A sill under a foundation. Ground, in relation to its load bearing and friction qualities.
  75. Forage Small baitfish, crayfish and other creatures that bass or other predator fish eat.
  76. Forage fish Generally, small fish that produce prolifically and are consumed by predators.
  77. Forb A weed or a broad-leafed plant.
  78. Forced outage Unscheduled shut down of a generating unit or other facility for emergency or other unforeseen reasons.
  79. Ford A place where a road crosses a stream under water.
  80. Forebay The water behind (upstream) of the dam.
  81. Forebay (headrace) Impoundment immediately upstream from a dam or hydroelectric plant intake structure.
  82. Forecast Crest The highest elevation of river level, or stage, expected during a specified storm event.
  83. Forecast Point A location that represents an area (reach of a river), where a forecast is made available to the public.
  84. Forepole A plank driven ahead of a tunnel face to support the roof or wall during excavation. See horsehead.
  85. Foreshore That part of the shore between the ordinary high-and low-watermarks and generally crossed by the tide each day.
  86. Foresight A sighting on a point of unknown elevation from an instrument of known elevation.
  87. 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…
  88. Formation Any sedimentary, igneous, or metamorphic material represented as a unit in geology; generally called rock, but not necessarily meeting the definition of…
  89. Formulation process First phase performed by the Early Warning System design team, which includes an Early Warning System reliability, local capabilities assessment, and…
  90. Fossorial insects Insects that live in the soil.
  91. Foundation The supportive structure of a building.
  92. Foundation drains Tile or pipe for collecting seepage within a foundation.
  93. Foundation material (foundation soil) The upper part of the earth mass carrying the load of the structure.
  94. Foundation of Dam The material on which the dam structure is placed. Often modified to provide more favorable hydraulic characteristics. See "Cutoff".
  95. Foundation surface The surface of the upper part of the earth mass carrying the load of the structure.
  96. 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.
  97. Fountainhead The upper end of a confined-aquifer conduit, where it intersects the land surface.
  98. Fracture (frack'chur)a broken bone.
  99. Fracture (joint) Crack or break in rocks along which no movement has occurred.
  100. Fracture Zone An area which has a great number of fractures.

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