Water terms starting with S

303 terms

Stage II Precipitation Processing The second level of precipitation processing, occurring within the WFO Advanced Weather Interactive Processing System (AWIPS) and performed on an hourly…
Stage III Precipitation Processing The third level of precipitation processing, performed interactively at RFCs. Stage II precipitation estimates from multiple radars are mosaiced into an…
Stage IV Precipitation Processing The fourth level of precipitation processing, performed automatically and/or interactively at NCEP.
Stair Stepping The process of continually updating river forecasts for the purpose of incorporating the effects rain that has fallen since the previous forecast was…
Stakeholder A person or group of people who are involved in a project and feel ownership.
Standard Hydrologic Exchange Format (SHEF) A documented set of rules for coding data for operational day-to-day use in a form for both visual and computer recognition.
Standby reserves Unused capacity in an electric system in machines that are not in operation but that are available for immediate use if required.
Standing Operating Procedures (SOP) A comprehensive single-source document covering all aspects of dam and reservoir operation and maintenance and emergency procedures.
Standpipe Pipe or tank connected to a closed conduit and extending to or above the hydraulic grade line of the conduit to afford relief from surges of pressure in…
State Emergency Response Commission (SERC) Appointed by the governor of each state for the designation of emergency planning districts, appoint LEPC's, supervise and coordinate their activities…
State organization The State government agency or office having the principal or lead role in emergency planning and preparedness.
Static head The difference in elevation between the pumping source and the point of delivery. The vertical distance between two points in a fluid.
Station Any one of a series of stakes or points indicating distance from a point of beginning or reference.
Station use Energy used in a generating plant as necessary in production of electricity. Includes energy consumed for plant light, power, and auxiliaries regardless…
Stationary white noise Random energy with statistical characteristics that do not vary with time.
Stator That portion of a machine which contains the stationary (non-moving) parts that surround the moving parts (rotor).
Stator windings The armature or stationary winding of a synchronous generator.
Steady flow Flow in an open channel is said to be steady if the depth of flow does not change over a given time interval. No change occurs with repect to time.
Steady state condition When model input values are nearly constant for a defined period of time.
Steam Water in vapor form; used as the working fluid in steam turbines and heating systems.
Stemming Crushed stone, soil, sand, or drill cuttings used to plug the unloaded portion of a drill hole.
Stewardship Careful and responsible management to ensure that goals and objectives are being achieved for the benefit of current and future generations.
Sticky limit The lowest moisture content at which a soil will stick to a metal blade drawn across the surface of the soil mass.
Stilling Basin Concrete portion downstream from conduit, tunnel, or control structure. A pool, usually lined with reinforced concrete, located below a spillway, gate, or…
Stilling pool A pool located below a spillway, gate, or valve into which the discharge dissipates energy to avoid downstream channel degradation.
Stockpile A storage pile of materials.
Stone A concretion of earthy or mineral matter; rock.
Stoney gate The fundamental difference between Stoney and fixed-wheel gates is that a moving train of rollers is substituted for the fixed wheels.
Stoping An upward erosion/piping action into an embankment or foundation (possibly leading to a breach).
Stoplogs Large logs, planks, cut timbers, steel or concrete beams placed on top of each other with their ends held in guides between walls or piers to close an…
Storage The retention of water or delay of runoff either by planned operation, as in a reservoir, or by temporary filling of overflow areas, as in the progression…
Storage Equation The equation for the conservation of mass.
Storm Hydrograph A hydrograph representing the total flow or discharge past a point.
Stormwater Discharge Precipitation that does not infiltrate into the ground or evaporate due to impervious land surfaces but instead flows onto adjacent land or water areas…
Strain A genetic variant within a species.
Strata (stratum) Distinct layers of stratified rock. A layer of sedimentary rock, visually separable from other layers above and below. Layers of rock.
Strategic plan A written plan outlining a government agency's framework for management.
Stratification Layering of a lake, by temperature, during warmer seasons.
Stratified reservoir A reservoir with several thermal layers of water.
Stratigraphy Geology that deals with the origin, composition, distribution, and succession of strata. Study or description of layered or stratified rocks.
stream A body of running water.
Stream capacity Total volume of water that a stream can carry within the normal high water channel.
Stream Gage A site along a stream where the stage (water level) is read either by eye or measured with recording equipment.
Stream line An imaginary line within the flow which is everywhere tangent to the velocity vector.
Stream Segment Refers to the surface waters of an approved planning area exhibiting common hydrological, natural, physical, biological, or chemical processes.
Streambed at the dam axis The lowest-point elevation in the streambed at the axis or centerline crest of the dam prior to construction.
Streamflow Discharge that occurs in a natural channel.
Stress The response of the body to physical, mental, or emotional pressure. This may make a person feel frustrated, angry, or anxious, and may cause unhealthy…
Striation Scratch or groove in bedrock caused by rocks within a glacier grinding the earth's surface as the glacier moves.
Strike Strike means a labor dispute wherein employees engage in a concerted stoppage of work (including stoppage by reason of the expiration of a collective…
Strip cropping A crop production system that involves planting alternating strips of row crops and close-growing forage crops; the forage strips intercept and slow…
Stripping Removal of a surface layer or deposit for the purpose of excavating other material beneath it.
Structural Height Distance between the lowest point in the excavated foundation (excluding narrow fault zones) and the top of dam.
Strut An inside brace.
Stud A popular term used for a length of wood or steel used in or for wall framing.
Sub-organization Any organization such as agencies, departments, offices, or local jurisdictions having a supportive role in emergency planning and preparedness.
Subbase A layer used in a pavement system between the subgrade and base course, or between the subgrade and portland cement concrete pavement.
Subcritical flow Those conditions of flow for which the depths are greater than critical and the velocities are less than critical.
Subdrilling Overdrilling or drilling below final grade. Sometimes necessary to assure that final grade is obtained when blasting.
Subgrade Soil prepared and compacted to support a structure or pavement system.
Subgrade surface The surface of the earth or rock prepared to support a structure or a pavement system.
Subirrigation Applying irrigation water below the ground surface either by raising the water table within or near the root zone, or by use of a buried perforated or…
Submerged aquatic vegetation (SAV) Aquatic vegetation, such as sea grasses, that cannot withstand excessive drying and therefore live with their leaves at or below the water surface.
Subsidence Sinking or settlement of the land surface, due to any of several processes. As commonly used, the term relates to the vertical downward movement of…
Substation An electrical installation containing power conversion (and sometimes generation) equipment, such as transformers, compensators, and circuit breakers.
Substation capacity The substation capacities are given in kVA (kilovolt-amperes). To determine the load in kilowatts, which could be served from the transformers, the…
Substrate 1. A compound that is altered by an enzyme. 2. Food source for growing cells or micro-organisms. 3. Material on which a sedentary organism lives and grows.
Subsurface irrigation system Irrigation by means of underground porous tile or its equivalent.
Subsurface Storm Flow The lateral motion of water through the upper layers until it enters a stream channel. This usually takes longer to reach stream channels than runoff.
Subtidal A marine or estuarine environment that lies below mean low water; always (or almost always) submerged in a tidally-influenced area.
Succession A series of dynamic changes by which one group of organisms succeeds another through stages leading to potential natural community or climax.
Sulfate attack Damage to concrete caused by the effects of a chemical reaction between sulfates in soils or ground water and hydrated lime and hydrated calcium aluminate…
Sump A pit or pool for draining, collecting, or storing water. A chamber located at the entrance to the pump which provides water to the pump.
Sump pump A pump used for removing collected water from a sump.
Supercritical flow Those conditions of flow for which the depths are less than critical and the velocities are greater than critical.
Supervisory control A system used to monitor conditions and operate mechanical features associated with a facility from a location other than at the site.
Supplemental irrigation service land Irrigable land now receiving, or to receive, an additional or reregulated supply of water through facilities constructed by or to be constructed by the…
Suppressed weir A rectangular weir that has only the crest far removed from the channel bottom, the sides are coincident with the sides of the approach channel, so no…
Surcharge An extra charge applied to the premium by an insurance company, usually applied as a result of at-fault accidents or moving violations.
Surcharge Capacity The volume of a reservoir between the maximum water surface elevation for which the dam is designed and the crest of an uncontrolled spillway, or the…
Surcharge capacity (surcharge storage) The reservoir capacity provided for use in passing the inflow design flood through the reservoir.
Surface Impoundment An indented area in the land's surface, such as a pit, pond, or lagoon.
Surface pump A mechanism for removing water or wastewater from a sump or wet well.
Surface Runoff Precipitation, snow melt, or irrigation in excess of what can infiltrate the soil surface and be stored.
Surface soil Upper part of the soil ordinarily moved in tillage, or its equivalent in uncultivated soils, about 10 to 20 cm in thickness.
Surface vibration A method of compacting soil using a vibrating plate or vibrating smooth drum roller used on the surface of soil placed.
Surface Water Water on the Earth's surface that is directly exposed to the atmosphere, as distinguished from water in the ground (groundwater).
Surge A rapid increase in the depth of flow.
Surge chamber A chamber or tank connected to a pipe and located at or near a valve that may quickly open or close or a pump that may suddenly start or stop.
Surge irrigation A surface irrigation technique wherein flow is applied to furrows (or less commonly, borders) intermittently during a single irrigation set.
Suspended The state of floating in water rather than being dissolved in it.
Suspended load (suspended sediment) Sediment that is supported by the upward components of turbulence in a stream and that stays in suspension for an appreciable length of time.
Suspension The temporary disqualification of a firm or individual from contracting with the government or participating in government programs, pending the outcome…
Sustainable Production The renewable living resources and their habitats, including, but not limited to, spawning, mating, and nursery grounds, and areas established to minimize…
Sustained Overdraft Long-term withdrawal from the aquifer of more water than is being recharged.
Swale A low place in a tract of land, usually moister, and often having denser vegetation than the adjacent higher land.
Swell Increase of bulk in soil or rock when excavated.
Swell pressure The pressure required to maintain zero expansion.
Switching station Facility equipment used to tie together two or more electric circuits through switches.
Synchronous condensers A synchronous machine running without mechanical load and supplying or absorbing reactive power.