Water terms starting with S

303 terms

Sacramento Soil Moisture Accounting Model (SACSMA) A hydrologic model which simulates the movement and occurrence of water in and on top of the ground.
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…
Saddle dam A subsidiary dam of any type constructed across a saddle or low point on the perimeter of a reservoir. See dike.
Safe Drinking Water Act (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…
Safe yield The amount of groundwater that can be withdrawn from a groundwater basin over a period of time without exceeding the long-term recharge of the basin or…
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…
Safety evaluation flood (SEF) The largest flood for which the safety of a dam and appurtenant structure(s) are to be evaluated.
Safety Evaluation of Existing Dams (SEED) examination The onsite examination performed initially and at predetermined intervals (approximately every 6 years).
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…
Saline A solution of salt and water.
Saline sodic land Soil that contains soluble salts in amounts that impair plant growth but not an excess of exchangeable sodium.
Saline water Water that contains more than 1,000 milligrams per liter of dissolved solids.
Salinity A measure of the amount of salt and other mineral substances dissolved in water.
Salmonids Family of fish that includes salmon and steelhead.
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…
Sample error Random variation reflecting the inherent variability within a population being counted.
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.
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.
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.
Sandstone Sedimentary rock composed of sand-sized grains (usually quartz) cemented together.
SARA Title III Superfund Amendments and Reauthorization Act of 1986 known as the Emergency Planning and Community Right-to-Know Act of 1986.
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.
Saturated unit weight The wet unit weight of soil when saturated. See unit weight.
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.
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…
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…
Scaling Prying loose pieces of rock off a face or roof to avoid danger of their falling unexpectedly.
Scatter When refering to photons and light, scattering describes the phenomenon of a source absorbing, and then emanating light in all directions.
Scheduled outage Shutdown of a generating unit, or other facility, for inspection or maintenance, in accordance with an advance schedule.
Schist A metamorphic rock formed from many types of rocks. Minerals in the rocks include micas, chlorite, talc, hornblende, and garnets.
Scour Erosion in a stream bed, particularly if caused or increased by channel changes.
Scrape A nest made from scratching in the ground.
screen A screen is a set of criteria against which you measure stocks or other investments to find those that meet your criteria.
Seam A layer of rock, coal, or ore.
Seashore The coastline of a sea or ocean, including the ground between the ordinary high water and low water marks.
Seasonal stream. See intermittent stream.
Secchi depth A measure of water clarity.
Second foot (sec-ft) Shortened term for cubic foot per second (cfs or ft3/s).
Second-Day Feet The volume of water represented by a flow of one cubic foot per second for 24 hours; equal to 84,000 cubic feet.
Secondary Embankment Embankment that blocks an area on a reservoiur rim that is lower than the top of the main dam. See also, "Levee".
section An area equal to 640 acres or 1 square mile.
Sediment Any finely divided organic and/or mineral matter deposited by air or water in nonturbulent areas.
Sediment concentration The quantity of sediment relative to the quantity of transporting fluid, or fluid-sediment misture. The concentration may be by weight or by volume.
Sediment discharge Rate at which sediment passes a stream cross-section in a given period of time, expressed in millions of tons per day (mtd).
Sediment load Mass of sediment passing through a stream cross section in a specified period of time, expressed in millions of tons (mt).
Sediment Storage Capacity The volume of a reservoir planned for the deposition of sediment.
Sediment yield Amount of mineral or organic soil material that is in suspension, is being transported, or has been moved from its site of origin.
Sediment yield rate The sediment yield per unit of drainage area.
Sedimentary Rock resulting from the consolidation of loose eroded sediment, remains of organisms, or crystals forming directly from water.
Sedimentation A process in which material carried in suspension by water flows into streams and rivers, increasing turbidity and eventually settling to the bottom.
Seep A spot where ground water oozes slowly to the surface, usually forming a pool.
Seepage The act or process involving the slow movement of water or other fluid through a porous material such as soil or rock.
Seepage collar A projecting collar of concrete built around the outside of a tunnel or conduit, within an embankment dam, to reduce seepage along the outer surface of…
Seepage force The force transmitted to the soil or rock grains by seepage.
Seepage loss Water loss by capillary action and slow percolation.
Seepage velocity The rate of discharge of seepage water through a porous medium per unit area of void space perpendicular to the direction of the flow.
Seiche wave A wave generated by either a landslide into a reservoir or by a sudden displacement or deformation of a fault line in a reservoir floor during a major…
Seismic Pertaining to any earth vibration, especially that of an earthquake.
Seismic evaluation criteria A guideline for determining which faults or seismic sources need to be assigned MCE's.
Seismic intensity Subjective measurement of the degree of shaking at a specified place by an experienced observer using a descriptive scale. See intensity scale.
Seismic parameters Descriptors of earthquake loading or earthquake size, such as magnitude, peak acceleration, location (distance and focal depth), spectrum intensity, or…
Seismo- Pertains to earthquakes.
Seismotectonic Of, relating to, or designating structural features of the earth which are associated with or revealed by earthquakes.
Seismotectonic Province A geographic area characterized by a combination of geology and seismic history.
Seize To bind wire rope with soft wire, to prevent it from ravelling when cut.
Select material Backfill materials specially selected and segregated from excavated materials.
Semipervious zone. See transition zone.
Sensitive species See Threatened, endangered, and sensitive species.
Separation deposit Sand deposit located at the upstream end of a recirculation zone, where downstream flow becomes separated from the channel bank.
Service Hydrologist The designated expert of the hydrology program at a WFO.
Service spillway (primary spillway) A structure located on or adjacent to a storage or detention dam over or through which surplus or floodwaters which cannot be contained in the allotted…
Settlement After negotiating, the amount you agree to accept from the insurance company as full payment for your loss.
Setup This referes to various adjustments that are made to the race car's suspension for handling at a specific racetrack.
Sewer tile Glazed waterproof clay pipe with bell joints.
Shaft The vertical segment of a column or pilaster between the base and the capital.
Shaft house House at top of the access shaft to gate chamber, which secures access to the gates.
Shaft or Morning Glory Spillway A vertical or inclined shaft into which flood water spills and then is conducted through, under, or around a dam by means of a conduit or tunnel.
Shaft spillway A vertical or inclined shaft into which water spills and then is conveyed through, under, or around a dam by means of a conduit or tunnel.
Shale A rock formed of consolidated mud. Fine-grained sedimentary rock formed from hardened clay and silt that typically splits into thin layers.
Shear Literally the sliding of one layer across another, with deformation and fracturing in the direction parallel to the movement.
Shear strength Internal resistance to stress (or movement) that comes from friction and cohesion of the sediment.
Shear wall A vertical lateral-force-resisting element in a structure assigned to resist wind or earthquake generated lateral forces.
Shear zone An area where the rock mass has moved along the plane of contact which often becomes a channel for ground water.
Sheepsfoot roller A tamping roller having lugs with feet extending at their outer tips.
Sheet Flow Flow that occurs overland in places where there are no defined channels, the flood water spreads out over a large area at a uniform depth.
Sheet piling Steel strips shaped to interlock with each other when driven into the ground.
Sheet wash A flow of rainwater that covers the entire ground surface with a thin film and is not concentrated into streams.
SHEFPARS A software decoder for SHEF Data.
shell See shoulder.
Shelterbelt A natural or planned barrier of trees or shrubs to reduce erosion and provide shelter from winds or storms.
Sheltering (in-place) A protective action that involves taking cover in upper levels of a building that is able to withstand high flood levels.
Shore ice An ice sheet in the form of a long border attached to the bank or shore; border ice.
Shoring Temporary bracing to hold the sides of an excavation from caving.
Short-throated flumes Short-throated flumes are considered short because they control flow in a region that produces curvilinear flow.
Shoulder (shell) The upstream and downstream parts of the cross section of an embankment dam on each side of the core or core wall.
Shrinkage Loss of bulk of soil when compacted in a fill.
Shrinkage index (SI) The numerical difference between the plastic and shrinkage limits.
Shrinkage limit (SL) The maximum water content at which a reduction in water content will not cause a decrease in volume of the soil mass.
Shrinkage ratio (R) The ratio of a given volume change, expressed as a percentage of the dry volume, to the corresponding change in moisture content above the shrinkage…
Side Channel Spillway A spillway whose crest is roughly parallel to the channel immediately downstream of the spillway.