SGLA LARE Section 4

SGLA LARE Section 4 Abrasion Wearing away by friction. (Site Eng for LAs) Alignment The course along which the centerline of a roadway or channel is located. (Site Eng for LAs) Angle of repose The angle that the sloping face of a bank of loose earth or gravel or other material makes with the horizontal. (Site Eng for LAs) Antecedent precipitation Rainfall that has recently preceded the storm event being analyzed. (Site Eng for LAs) Area drain A structure for collecting runoff from relatively small paved areas (Site Eng for LAs) Backfill Earth or other material used to replace material removed during construction, such as in pipeline and culvert trenches and behind retaining walls (Site Eng for LAs) Base (Base Course) A layer of specified or selected material of planned thickness, constructed on the subbase or on natural subgrade to distribute the load and provide drainage, or on which a wearing surface or a drainage structure is placed (Site Eng for LAs) Bearing capacity (soil) The load-supporting capacity of a soil (Site Eng for LAs) Bench A horizontal or sloping step in a slope (Site Eng for LAs) Bioretention A technique that uses parking lot islands, planting strips, or swales to collect and filter stormwater (BMPs) (Site Eng for LAs) Blading Planing or smoothing the ground surface (Site Eng for LAs) Borrow Fill material imported to a site (Site Eng for LAs) Borrow area, borrow pit A source of earth fill materials used in the construction of embankments or other earth fill structures (Site Eng for LAs) Brush layering Live branch cuttings laid in crisscross fashion on benches between successive lifts of soil (Site Eng for LAs) Caisson Similar to a pile; however, rather than driven, holes are drilled into the ground and filled with concrete (Site Eng for LAs) Catch basin A receptacle with a sediment bowl or sump, for diverting surface water to a subsurface pipe (Site Eng for LAs) Centerline The survey line in the center of a road, ditch, or similar project (Site Eng for LAs) Channel A natural stream, or a ditch or swale constructed to convey water (Site Eng for LAs) Cluster development A land planning technique to concentrate buildings on a portion of a site in order to preserve open space and environmentally sensitive areas (Site Eng for LAs) Compaction The densification of a soil by a mechanical process (Site Eng for LAs) Constructed wetland Artificially created wetland primarily to treat point and non-point sources of water pollution Continuity equation A formula expressing the principle of conservation of mass as applied to the flow of water (or other fluids of constant density). It states that the product of cross-section of flow and velocity at any point in a channel is a constant (Site Eng for LAs) Contour line An imaginary line, or its representation on a map, following all points at the same elevation above or below a given datum (Site Eng for LAs) Cordonata A grade change device that is a combination of stairs and a ramp, where treads are long, usually more than a single human stride, and sloping (Site Eng for LAs) Critical depth The depth of flow in an open channel at which critical flow occurs. For a given flow rate, depths greater than critical result in subcritical, or tranquil, flow. Those smaller than critical result in supercritical, or rapid, flow. (Critical flow = unstable flow in an open channel) (Site Eng for LAs) Critical flow An unstable flow condition in an open channel that occurs at critical depth (Site Eng for LAs) Critical velocity The velocity at which unstable flow conditions begin to occur (Site Eng for LAs) Crown The rise or difference in elevation between the edge and the centerline of a roadway (Site Eng for LAs) Culvert Any structure, not classified as a bridge, that provides a waterway or other opening under a road (Site Eng for LAs) Cut section (or cut) The part of the ground surface that, when graded, is lower th