Earthern cattle tankA watering area or basin for cattle that is usually created in a natural drainage area by obstructing natural water flows with berms of soil.
EarthquakeGround shaking caused by the sudden release of energy stored in rock beneath the Earth's surface.
Ecological resourcesBiota (fish, wildlife, and plants) and their habitats, which may be land, air, or water.
Ecological segmentationDevelopment that fragments animal habitat and does not provide corridors for movement.
EcoregionA geographically distinct area of land that is characterized by a distinctive climate, ecological features, and plant and animal communities.
EcosystemA complex ecological community or environment forming a functioning whole.
EcotonesThe borders between two different types of ecosystems or communities (e.g., a forest and a grassland) containing characteristic species of each.
Edge habitatThe transitional zone where one cover type ends and another begins.
Edge-onA descriptor for the appearance of solar facility collector/reflector arrays when viewed at very low vertical angles, such that the viewing angle is at or…
EffectsEnvironmental consequences (the scientific and analytical basis for comparison of alternatives) as a result of a proposed action.
EfficiencyUnder the First Law of Thermodynamics, efficiency is the ratio of work or energy output to work or energy input, and cannot exceed 100 percent.
EffigyAn object bearing the likeness of an animal or human.
EffluentThe treated waste water discharged by sewage treatment plants.
Electric and magnetic field (EMF)Electric and magnetic fields are generated when charged particles (e.g., electrons) are accelerated. Charged particles in motion produce magnetic fields.
Electrolytes (battery)A nonmetallic (liquid or solid) conductor that carries current by the movement of ions (instead of electrons) with the liberation of matter at the…
ElectronA sub-atomic particle that has a negative electric charge.
EmbryotoxicityAdverse effects on the embryo due to a substance that enters the maternal system and crosses the placental barrier.
EmergentAquatic plants having some or most of the leaf area extending out of the water.
Emergent wetlandsThe Emergent wetland class is characterized by erect, rooted, herbaceous hydrophytes, excluding mosses and lichens.
Emission FactorA measure of the average amount of a specified pollutant or material emitted for a specific type of fuel or process.
EmissionsWaste substances released into the air or water.
Endangered speciesA plant or animal species in immediate danger of extinction because its population number has reached a critical level, or its habitat has been…
Endangered Species Act of 1973 (ESA)Requires consultation with the U.S. Fish and Wildlife Service and/or the National Marine Fisheries Service to determine whether endangered or threatened…
EndemicWhere disease occurs on a consistent basis.
EntrainmentThe incorporation of fish, eggs, larvae, and other plankton with intake water flow entering and passing through a cooling water intake structure and into…
EntryAn application to acquire title to public lands.
Environmental Assessment (EA)A public document that analyzes a proposed federal action for the possibility of significant environmental impacts.
Environmental Impact Statement (EIS)A comprehensive study of likely environmental impacts resulting from major federally-assisted projects; statements are required by the National…
Environmental JusticeIs based on the principle that all people have a right to be protected from environmental pollution and to live in and enjoy a clean and healthful…
Environmental mediaSoil, water, air, biota, or any other parts of the environment that can contain contaminants.
EolianRefers to the processes of wind erosion, transport, and deposition. For example, sand dunes are landforms produced by eolian processes in arid…
Ephemeral allotmentA BLM grazing allotment in areas of the Hot Desert Biome (Region) that do not consistently produce enough forage to sustain a livestock operation, but…
Ephemeral streamA stream that flows only after a storm or during snowmelt and whose channel is, at all times, above the water table; groundwater is not a source of water…
ErosionThe wearing away of land surface by wind or water, intensified by land-clearing practices related to farming, residential or industrial development, road…
EruptionThe process by which solid, liquid, and gaseous materials are ejected into the Earth's atmosphere and onto the Earth's surface by volcanic activity.
EscarpmentA cliff or the steep slopes of a plateau edge.
Ethnobotany (ethnobotanical)The plant lore and agricultural customs of a people; the study of such lore and customs.
EutecticA mixture of substances that has a melting point lower than that of any mixture of the same substances in other proportions.
Evaporation pondsShallow man-made ponds designed to contain liquid effluents and concentrate the residual waste through evaporation.
Evaporation RateIn hydrologic terms, the quantity of water, expressed in terms of depth of liquid water, which is evaporated from a given surface per unit of time.
EvapotranspirationThe net water loss (in vapour form) per unit area of land, both directly from the land surface, and indirectly through transpiring leaves.
ExceedanceA measured level of an air pollutant that is higher than the national or state ambient air quality standards. See also NAAQS and CAAQS
Excessive gradesGround surface inclines relative to the horizon beyond which the ground may become unstable.
Executive OrderA president's or governor's declaration which has the force of law, usually based on existing statutory powers, and requiring no action by the Congress or…
exposureContact of an organism with a chemical, radiological, or physical agent.