NPDP Dam Dictionary

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Term AKA Definition
Lacustrine habitat Lake or reservoir wetland habitat.
Lagomorphs The order of mammals including rabbits, hares, and pikas.
Laminar flow The flow field can be characterized by layers of fluid, one layer not mixing with adjacent ones. The flow is laminar or turbulent depending on the value of the Reynolds number, which is a dimensionless ratio of the inertial forces to the viscous forces. In laminar flow, viscous forces are dominant and the Reynolds number is relatively small. In turbulent flow, the inertial forces are very much greater than the viscous forces and the Reynolds number is large. Laminar flow occurs very infrequently in open channel flow.
Land classification Reclamation's systematic placing of lands into classes based on their suitability for sustained irrigated farming. Land classes are defined by productivity, with class 1 being the most productive. For other classes, the equivalent acreage to class 1 for the same productivity is defined (class 1 equivalency). For example, (the productivity of) X acres of class 2 land is equal to (the productivity of) 1 acre of class 1 land.
Land ownership Land held in title
Land retirement Permanent removal of land from agricultural production.
Landholder A landholder is an individual or legal entity owning or leasing land subject to the acreage limitation provisions.
Lateral A channel that conveys water from a canal to a farm, municipality, etc.
Latitude The latitude at the dam centerline as a single value in decimal degrees (e.g., 49.75).
Leaching field A lined or partially lined underground pit into which raw household water (sewage) is discharged and from which the liquid seeps into the surrounding soil. Also called a leaching cesspool.
Leakage Free flow loss of water through a hole or crack.
Lease of power privilege Contractual right given to a non-Federal entity to utilize, consistent with project purposes, water power head and storage from Reclamation projects for electric power generation.
Left abutment See abutment.
Left or Right Designation The designation of left or right is made with the observer looking downstream.
Length of dam See crest length.
Lentic Standing waters, such as lakes, ponds, and marshes.
Levee See dike.
Life cycle Various stages an animal passes through from egg fertilization to death.
Lift A step or bench in a multiple layer excavation or fill.
Lift line Horizontal construction joint created when new concrete is placed on previously placed concrete.
Limnological conditions Conditions on freshwater lakes.
Limnology Scientific study of the physical characteristics and biology of lakes, ponds, and streams.
Lineament A rectilinear topographic feature.
Lining Any protective material used to line the interior surface of a conduit, pipe, or tunnel. With reference to a canal, tunnel or shaft, a coating of asphaltic concrete, concrete, reinforced concrete, or shotcrete to provide watertightness, to prevent erosion, or to reduce friction.
Liquefaction When a solid form is turned into a liquid form. During an earthquake, low density materials act like water and lose their supporting strength.
Liquid limit The water content corresponding to the arbitrary limit between the liquid and plastic states of consistency of a soil; the water content at which a pat of soil, cut by a groove of standard dimensions, will flow together for a distance of 1/2 inches under the impact of 25 blows in a standard liquid limit apparatus.
Littoral Pertaining to the shore.
Live capacity Live Storage That part of the total reservoir capacity which can be withdrawn by gravity. This capacity is equal to the total capacity less the dead capacity.
Load Amount of electrical capacity or energy delivered at a given point. The power output of an engine or powerplant under given circumstances.
Load factor The ratio of an average load to the maximum load.