NPDP Dam Dictionary

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Term AKA Definition
Esthetics An emotional judgment about what is beautiful or pleasing.
Eutrophic Nutrient enrichment of a body of water that contains more organic matter than existing biological oxidization processes can consume. A body of water which has become, either naturally or by pollution, rich in nutrients and often seasonally deficient in dissolved oxygen.
Eutrophication A process where more organic matter is produced than existing biological oxidization processes can consume.
Evaporation Water losses to vapor from water surfaces, sprinkler irrigation, etc.
Excavation The action or process of excavating (to dig or remove earth). See common excavation, rock excavation, and unclassified excavation.
Excess capacity Power generation capacity available on a short- term basis that exceeds the firm energy on a long-term contract offered to an electricity customer.
Excess land Irrigable land, other than exempt land, owned by any landowner in excess of the maximum ownership entitlement under applicable provision of reclamation law.
Exclusive flood control capacity The reservoir capacity assigned to the sole purpose of regulating flood inflows to reduce flood damage downstream. In some instances, the top of exclusive flood control capacity is above the maximum controllable water surface elevation. See flood control capacity.
Exempt land Irrigation land in a district to which the acreage limitation and pricing provisions of Reclamation law do not apply.
Existence value Value people place on simply knowing an area or feature continues to exist in a particular condition.
Existing ground The earth's surface as it is prior to any work. See original ground surface.
Exit channel See outlet channel.
Exotic species A non-native species that is introduced into an area.
Expansion joint A separation between adjoining parts of a concrete structure which is provided to allow small relative movements, such as those caused by temperature changes, to occur independently. A flexible filler is provided in the joint, reinforcement does not pass through the joint.
Exploit Excavate in such a manner as to utilize material in a particular vein or layer, and waste or avoid surrounding material.
Extirpated species A species rendered extinct in a given area.
Face Exposed surface of dam materials (earth, rockfill, or concrete), upstream and downstream. The external surface which limits the structure, see neatlines. The more or less vertical surface of rock exposed by blasting or excavating. The cutting end of a drill hole.
Facilities Structures associated with Reclamation irrigation projects, municipal and industrial water systems, power generation facilities, including all storage, conveyance, distribution, and drainage systems.
Facing With reference to a wall or concrete dam, a coating of a different material, masonry or brick, for architectural or protection purposes, e.g., stonework facing, brickwork facing. With reference to an embankment dam, an impervious coating or face on the upstream slope of the dam.
Factor of safety The ratio of the ultimate strength of the material to the allowable or working stress.
Fallow Land plowed and tilled and left unplanted.
False set See horsehead.
Fatality Injury Description Describe where or how fatalities and injuries occurred.
Fault A fracture in rock along which the adjacent rock surfaces are differentially displaced.
Fault A shear with significant continuity that can be correlated between observation points.
Faulting The movement which produces relative displacement along a fracture in rock.
Fauna All animals associated with a given habitat, country, area, or period.
Feasibility estimate An estimate used for determining the economic feasibility of a project, the probable sequence and cost for construction of a project, and as a guide in the choice between alternative locations or plans.
Feather To blend the edge of new material smoothly into the old surface.
Fill Manmade deposit of natural soils or the process of the depositing. An earth or broken rock structure or embankment. Soil or loose rock used to raise a grade. Soil that has no value except as bulk