Water — page 25 of 31

3,083 terms

Water terms

  1. Riffle A stretch of choppy water caused by an underlying rock shoal or sandbar. A run is a long riffle.
  2. Riffle and pool complex A water habitat composed of riffles (characterized by water flowing rapidly over a coarse substrate) and pools (deeper areas of water associated with…
  3. Right Abutment See abutment.
  4. Right of way The right of a party to pass over the land of another.
  5. Right. A temporary privilege granted to existing common shareholders to purchase additional shares directly from the company at a stated price.
  6. Rigid pipe Pipe designed to transmit the backfill load to the foundation beneath the pipe. Rigid pipe must be supported on the bottom portion of the pipe.
  7. Rill A small and shallow incision into topsoil layers resulting from erosion by overland flow or surface runoff that is common on slopes of unvegetated ground…
  8. Ring gate A ring- or annular-shaped steel drum operating in a recess or gate chamber in a spillway crest and controlled in a manner similar to a drum gate. See gate.
  9. Ring seal gate Similar to a paradox gate, however sealing is by a moveable seal, which is extended by water pressure when the gate is closed.
  10. Ring-follower gate A gate consisting of a rectangular leaf and an opening equal in diameter to that of the conduit that forms an unobstructed passageway when the leaf is in…
  11. Rip Rap A layer of stones, broken rock or precast blocks placed in random fashion on the upstream slope of an embankment dam, on a reservoir shore or on the sides…
  12. Riparian Relating to, living in, or located on the bank of a river, lake, or tidewater.
  13. Riparian Zone The transition zone between the water and the upland zone. Can be identified by specific types of plants and soils.
  14. Ripple In a streambed, a ripple is a small triangle-shaped elements having gentle upstream slopes and steep downstream slopes.
  15. Riprap A man-made stretch of rocks or material of a hard composition that usually extends above and below the shoreline, often found near dams of big…
  16. Risk The possibility of loss; the uncertainty of future returns.
  17. risk assessment a scientifically based process consisting of the following steps: i) hazard identification; ii) hazard characterization; iii) exposure assessment; and iv)…
  18. River Basin The land area surrounding one river from its headwaters to its mouth. The area drained by a river and its tributaries.
  19. River corridor A river and the strips of land adjacent to it, including the talus slopes at the bases of cliffs, but not the cliffs themselves.
  20. River Flooding The rise of a river to an elevation such that the river overflows its natural banks causing or threatening damage.
  21. River Forecast (RVF) (RVF) An internal product issued by RFCs to other NWS offices. An RVF contains stage and/or flow forecasts for specific locations based on existing, and…
  22. River Forecast Center (RFC) (RFC) Centers that serve groups of Weather Forecast Offices, in providing hydrologic guidance and is the first echelon office for the preparation of river and…
  23. River Gage A device for measuring the river stage.
  24. River Gage Datum The arbitrary zero datum elevation which all stage measurements are made from.
  25. River Ice Statement (RVI) (RVI) A public product issued by the RFC's containing narrative and numeric information on river ice conditions.
  26. River mile (RM) A unit of measurement (in miles) used on rivers.
  27. River Observing Station An established location along a river designated for observing and measuring properties of the river.
  28. River outlet works (row) See outlet works.
  29. River Recreation Statement (RVR) (RVR) A statement released by the NWS to inform river users of current and forecast river and lake conditions.
  30. River Statement (RVS) (RVS) A product issued to communicate notable hydrologic conditions which do not involve flooding, i.e., within river bank rises, minor ice jams, etc.
  31. River Summary (RVA) (RVA) A NWS summary of river and/ or crest stages for selected forecast points along the river.
  32. River System All of the streams and channels draining a river basin.
  33. River trash wall Walls constructed to deflect heavy floating debris away from the upper ends of a fishway.
  34. Riverine Riparian; pertaining to a riverbank.
  35. Rock A player who plays very tight, not very creatively. He raises only with the best hands.
  36. Rock anchor A steel rod or cable placed in a hole drilled in rock, held in position by grout, mechanical means, or both.
  37. Rock bolt A steel rod placed in a hole drilled in rock, held in position by grout, mechanical means, or both. A rock bolt can be pretensioned.
  38. Rock excavation Hard and firm parts of the earth's crust which is dug out and removed from a particular site or area, see rock.
  39. Rock Fill Dam An embankment dam in which more than 50% fo the total volume comprises compacted or dumped pervious natural or crushed rock.
  40. Rock fragment Detached pieces of rock which generally are not rounded.
  41. Rockfill Dam An embankment dam in which more than 50 percent of the total volume is comprised of compacted or dumped cobbles, boulders, rock fragments, or quarried…
  42. ROD A graduated staff used in determining the difference in elevation between two points.
  43. Rolled Earth Dam See "Embankment Dam".
  44. Rolled Earth Dam (Earth Fill or Earth Dam) An embankment dam in which more than 50% of the total volume is formed of compacted fine-grained material obtained from a borrow area.
  45. Rolled fill dam An embankment dam of earth or rock in which the material is placed in layers and compacted by the use of rollers or rolling equipment.
  46. Rolled Filled Dam An embankment dam of earth or rock in which the material is placed in layers and compacted by using rollers or rolling equipment. Same as Rockfill dam.
  47. Roller compacted concrete (RCC) A mixture of cement, water, and aggregate compacted by rolling.
  48. Roller drum gate. See drum gate.
  49. Roller gate A gate rolled up or down inclined supporting rails by a hoist through sprocket chains around the ends of a cylinder.
  50. Roller-compacted concrete dam A concrete gravity dam constructed by the use of a dry mix concrete transported by conventional construction equipment and compacted by rolling, usually…
  51. Rolling A method of compacting soil using a sheepsfoot roller or a smooth drum roller.
  52. Root zone The volume of soil or growing medium containing the roots of a plant. In soil science, the depth of the soil profile in which roots are normally found.
  53. Rotten Ice Ice in an advanced stage of disintegration.
  54. Rough fish A nonsport fish.
  55. Route alerting A supplement to the public alert system; a method for alerting people in areas not covered by the primary system or if the primary system fails.
  56. Routing The methods of predicting the attenuation of a flood wave as it moves down the course of a river.
  57. Rubble dam A stone masonry dam in which the stones are unshaped or uncoursed. See dam.
  58. Run Seasonal upstream migration of anadromous fish. One or more lengths of pipe that continue in a straight line.
  59. Run-of-river plants The regulated inflow of one powerplant is equal to the outflow from a powerplant upstream.
  60. Running and quick-start capability The net capability of generating units that carry load or have quick-start capability.
  61. Runoff The water that flows off the surface of the land, ultimately into our streams and water bodies, without being absorbed into the soil.
  62. Runup The vertical distance above the setup that the rush of water reaches when a wave breaks on the dam embankment.
  63. Rural area Predominantly agricultural, prairie, forest, range, or undeveloped land where the population is small.
  64. Rural electric cooperative (cooperatively-owned electric utility) A customer-owned electric utility that was created to transmit and distribute power in rural areas.
  65. Sacramento Soil Moisture Accounting Model (SACSMA) (SACSMA) A hydrologic model which simulates the movement and occurrence of water in and on top of the ground.
  66. Sacred site Any specific, discrete, narrowly delineated location on federal land that is identified by an Indian tribe, or Indian individual determined to be an…
  67. Saddle dam A subsidiary dam of any type constructed across a saddle or low point on the perimeter of a reservoir. See dike.
  68. Safe Drinking Water Act (SDWA) (SDWA) The Safe Drinking Water Act (SDWA) ensures that our tap water is fit to drink. Passed in 1974, SDWA sets national drinking water standards for public…
  69. Safe yield The amount of groundwater that can be withdrawn from a groundwater basin over a period of time without exceeding the long-term recharge of the basin or…
  70. Safety Evaluation Earthquake (SEE) The earthquake expressed in terms of magnitude and closest distance from the damsite or in terms of the characteristics of the time history of free-field…
  71. Safety evaluation flood (SEF) The largest flood for which the safety of a dam and appurtenant structure(s) are to be evaluated.
  72. Safety Evaluation of Existing Dams (SEED) examination The onsite examination performed initially and at predetermined intervals (approximately every 6 years).
  73. Safety Evaluation of Existing Dams (SEED) report A compilation of independent technical reports that evaluate the design, construction, and performance of a dam for its structural and hydraulic integrity…
  74. Saline A solution of salt and water.
  75. Saline sodic land Soil that contains soluble salts in amounts that impair plant growth but not an excess of exchangeable sodium.
  76. Saline water Water that contains more than 1,000 milligrams per liter of dissolved solids.
  77. Salinity A measure of the amount of salt and other mineral substances dissolved in water.
  78. Salmonids Family of fish that includes salmon and steelhead.
  79. Saltation The movement of sand or fine sediment by short jumps above a streambed under the influence of a water current too weak to keep it permanently suspended in…
  80. Sample error Random variation reflecting the inherent variability within a population being counted.
  81. Sand A rock or mineral fragment of any composition that has a diameter ranging from 0.5 to 2.0 mm. Sand has a gritty feel.
  82. Sand backfill Material which has a particle size which varies from a No. 4 sieve to a No. 200 sieve and is used for refilling an excavation.
  83. Sand boil A sand boil is sand and water that come out onto the ground surface during an earthquake as a result of liquefaction at shallow depth.
  84. Sandstone Sedimentary rock composed of sand-sized grains (usually quartz) cemented together.
  85. SARA Title III Superfund Amendments and Reauthorization Act of 1986 known as the Emergency Planning and Community Right-to-Know Act of 1986.
  86. Satellite Hydrology Program A NOHRSC program that uses satellite data to generate areal extent of snow cover data over large areas of the western United States.
  87. Saturated unit weight The wet unit weight of soil when saturated. See unit weight.
  88. Saturated zone A zone in which all voids are filled with water. The area below the water table where all open spaces are filled with water. See ground water.
  89. Saturation (and internal vibration) A method of compacting soil using water added to soil and internal vibrators (such as a concrete vibrator) are worked down through the depth of soil…
  90. Scale Ratio of map distance to Earth distance. Thus, in a 1:24,000 scale map, one centimeter, inch, or foot equals 24,000 centimeters, inches, or feet on the…
  91. Scaling Prying loose pieces of rock off a face or roof to avoid danger of their falling unexpectedly.
  92. Scatter When refering to photons and light, scattering describes the phenomenon of a source absorbing, and then emanating light in all directions.
  93. Scheduled outage Shutdown of a generating unit, or other facility, for inspection or maintenance, in accordance with an advance schedule.
  94. Schist A metamorphic rock formed from many types of rocks. Minerals in the rocks include micas, chlorite, talc, hornblende, and garnets.
  95. Scour Erosion in a stream bed, particularly if caused or increased by channel changes.
  96. Scrape A nest made from scratching in the ground.
  97. screen A screen is a set of criteria against which you measure stocks or other investments to find those that meet your criteria.
  98. Seam A layer of rock, coal, or ore.
  99. Seashore The coastline of a sea or ocean, including the ground between the ordinary high water and low water marks.
  100. Seasonal stream. See intermittent stream.

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