Solar CellA solar photovoltaic device with a specified area.
Solar CollectorA device used to collect, absorb, and transfer solar energy to a working fluid.
Solar collector arrayThat portion of the solar energy facility containing components that track and capture sunlight and convert it to other useful forms of energy, typically…
Solar energyElectromagnetic energy transmitted from the sun (solar radiation). The amount that reaches the earth is equal to one billionth of total solar energy…
Solar energy technologyAny engineered method for harnessing, storing, and using the Sun's energy.
Solar Energy Zone (SEZ)Lands identified by the BLM as best-suited for large-scale production of solar energy.
Solar trackingThe solar panels can be swiveled using the electric motors to follow the path of the sun exactly in the course of the day to maximize the yields.
Sole source aquiferAn aquifer that supplies 50 percent or more of the drinking water of an area.
Solid wasteAll unwanted, abandoned, or discarded solid or semisolid material whether or not subject to decomposition, originating from any source.
SourceAny place or object from which air pollutants are released. Sources that are fixed in space are stationary sources and sources that move are mobile…
Southwest Regional Gap Analysis Project (SWReGAP)The Southwest Regional Gap Analysis Project is an update of the Gap Analysis Program's mapping and assessment of biodiversity for the five-state region…
Spawning gravelSorted, clean gravel patches of a size appropriate for the needs of resident or anadromous fish.
Special areasAreas of high public interest and containing outstanding natural features or values.
Special Use Airspace (SUA)Airspace of defined dimensions identified by an area on the surface of the Earth wherein activities must be confined because of their nature and/or…
Specially Designated AreasIncludes a variety of areas that have received recognition or designation because they possess unique or important resource values.
Species of Special ConcernA species that may have a declining population, limited occurrence, or low numbers for any of a variety of reasons.
Specular reflectionAlso known as direct reflection, regular reflection, or mirror reflection. The reflection of electromagnetic rays without scattering or diffusion.
Spill lightLight that falls outside of the area intended to be lighted.
Spotted owl habitatDispersal habitat: Forest vegetation with at least 40% canopy closure and an average stand diameter of 11".
Spreader stoker furnaceA furnace in which fuel is automatically or mechanically spread. Part of the fuel is burned in suspension. Large pieces fall on a grate.
SpringThe point at which the water table meets Earth's surface, causing water to flow from the ground.
Sprinkler systemConsists of pipelines which carry water under pressure from a pump or elevated source to lateral lines along which sprinkler heads are spaced at…
staging areaA designated area where construction equipment is temporarily stored (usually only during the construction phase).
StandTo decline additional cards and keep your existing total.
Stand conversionThe conversion of a noncommercial stand of timber to a commercial stand.
Stand densityThe number or mass of trees occupying a site. It is usually measured in terms of stand density index or basal area per acre.
Standards and guidelinesBounds or constraints within which all practices in a given area will be carried out, in achieving the goals and objectives for that area.
State Historic Preservation Officer (SHPO)The State officer charged with the identification and protection of prehistoric and historic resources in accordance with the National Historic…
State Implementation Plan (SIP)A state plan required by the Clean Air Act to bring nonattainment areas into compliance with federal ambient air quality standards.
Steam amendment chemicalsChemicals used to treat raw water to remove certain chemical species, thus amending its hardness or pH, making it suitable for use in a steam cycle.
Steam TurbineA device that converts high-pressure steam, produced in a boiler, into mechanical energy that can then be used to produce electricity by forcing blades in…
Steam turbine-generator (STG)A device that uses high-pressure steam, produced in a boiler, to drive the blades of a turbine to produce mechanical energy that can then be used to…
Steep slopesGround surface that rises precipitously above the horizon.
StillageThe grains and liquid effluent remaining after distillation.
Stirling EngineA heat engine of the reciprocating (piston) where the working gas and a heat source are independent.
Stoichiometric conditionThat condition at which the proportion of the air-to-fuel is such that all combustible products will be completely burned with no oxygen remaining in the…
StolonA lateral stem that grows horizontally along the ground surface. Used by some plant species as a mechanism for dispersal, since stolon nodes can…
stoverThe dried stalks and leaves of a crop remaining after the grain has been harvested.
StrataSingle, distinct layers of sediment or sedimentary rock.
Stratigraphy (stratigraphic)Layers of sediments and rocks that reflect the geologic history of an area. With respect to cultural resources and archaeological sites, the relative…
Stream classClassification of streams based on the present and foreseeable uses made of the water, and the potential effects of on-site changes on downstream uses.
Stream terraceA remnant of a floodplain surface formed by streams as they carve downward into their floodplains.
StressorsPhysical, chemical, or biological entities that can induce adverse effects on ecosystems or human health.
Strike-slip faultVertical (or nearly vertical) fractures where the blocks have mostly moved horizontally.
structural chemical analysisThe composition of biomass reported by the proportions of the major structural components; cellulose, hemicellulose, and lignin.
Structural firesFire originating in and burning any part or all of any building, shelter, or other structure.
StructureChanges in the shape of the bottom of lakes, rivers, or impoundments, especially those that influence fish behavior.
Stumpage(1) Standing live or dead uncut trees. (2) The value or rate paid to purchase standing trees for harvest.
Sub-canopiesWoody vegetation that grows beneath the canopy or tree tops of a forest or woodland.
SubalpineThe upper mountain vegetation immediately below the cold limits of tree and tall shrub growth.
SubdrainageA land area (basin) bounded by ridges or similar topographic features, encompassing only part of a watershed.
SubsidenceSinking or settlement of the land surface, due to any of several processes. As commonly used, the term relates to the vertical downward movement of…
SubsistenceThe practices by which a group or individual acquires food, such as through hunting and gathering, fishing, and agriculture.
SubstationAn electrical installation containing power conversion (and sometimes generation) equipment, such as transformers, compensators, and circuit breakers.
Substrate1. 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.
SuccessionA series of dynamic changes by which one group of organisms succeeds another through stages leading to potential natural community or climax.
Sulfur dioxide (SO<sub>2</sub>)SO2 is a key pollutant in the formation of acid rain and contributes to the formation of fine particles that are associated with significant negative…
Sulfur oxides (SO<sub>x</sub>)Compounds containing sulfur and oxygen, such as sulfur dioxide (SO2) and sulfur trioxide (SO3).
Sunk costA cost already incurred and therefore not considered in making a current investment decision.
Superheated steamSteam at a given pressure which is above the temperature which corresponds to boiling temperature at that given pressure.
Surface expressionRefers to the physical expression of seismic activity at the ground exterior in the form of a fault rupture or fissure.
Surface ruptureThe breakage of ground along the surface trace of a fault caused by the intersection of the fault surface area ruptured in an earthquake with the Earth's…
Surface textureThe visual manifestations of the interplay of light and shadow created by the variations in the top of an object or landscape.
Surface WaterWater on the Earth's surface that is directly exposed to the atmosphere, as distinguished from water in the ground (groundwater).
Surplus electricityElectricity produced by cogeneration equipment in excess of the needs of an associated factory or business.
Suspended solidsWaste particles suspended in water. Suspended solids can harbor harmful microorganisms and toxic chemicals.
SustainableAn ecosystem condition in which biodiversity, renewability, and resource productivity are maintained over time.
Sustained yieldThe maintenance in perpetuity of regular, periodic harvest of wood resources from forest land without damaging the productivity of the land.
SwaleA low place in a tract of land, usually moister, and often having denser vegetation than the adjacent higher land.
Swarm (seismic swarm)A localized surge of earthquakes, with no one shock being conspicuously larger than all other shocks of the swarm.
SyngasA syntheses gas produced through gasification of biomass. Syngas is similar to natural gas and can be cleaned and conditioned to form a feedstock for…
syringylA component of lignin, normally only found in hardwood lignins. It has a six-carbon aromatic ring with two methoxyl groups attached.