Erosion and Sediment Pollution Control Program Manual.pdf

Aquiclude -----A geologic formation with insufficient permeability to allow for significant passage of
water.
Aquifer -----A saturated or partially saturated geologic formation with sufficient permeability to hold and
transmit water in quantities suitable for an intended use.
Aquitard -----A geologic formation without sufficient permeability to permit sufficient groundwater flow
to meet an intended use.
Arable -----Land suitable for growing crops.
Archaeological Field investigation -----Extensive controlled excavation of an archaeological site to
study the cultural history using professionally accepted means of sampling, removing and
excavating archaeological specimens, also known as phase three archaeological research or
data recovery.
Archaeological Survey -----A visual inspection and limited sampling and excavation of an
archaeological site to determine the characteristics and physical extent of a site, also known as
phase one or phase two archaeological research.
Armor -----A protective covering for an area that is otherwise exposed to erosion.
Army Corps of Engineers (ACOE) -----A federal agency that in its civilian role, plans and executes
national programs for navigation and commerce, flood control, water supply, hydroelectric
power generation, recreation, conservation, and preservation of the environment.
Artesian Aquifer -----A confined aquifer with a piezometric height greater than the height of the aquifer.
Artesian Spring -----Water from an artesian aquifer which flows to the surface naturally.
Artesian Well -----Any well this taps into an artesian aquifer, even if the water surface does not reach
the top of the well.
Articulated Concrete Block Revetment System ----- A matrix of individual concrete blocks placed
together to form an erosion resistant overlay that meets specific design parameters.
Articulated Concrete Mattress -----Rigid concrete slabs, which can move as scour occurs without
separating, usually hinged together with corrosion-resistant wire fasteners; primarily placed for
lower bank protection.
Articulation -----The state of being jointed or interrelated; a joint or juncture between parts or
structures.
Artificial Recharge -----The practice of increasing, by artificial means, the amount of water that enters
a ground water reservoir.
As-Built (Record Drawing) -----Drawing or certification (with a P.E. seal) of structures as they were
actually constructed
ASCE -----American Society of Civil Engineers.
Asphalt Emulsion -----A mixture of asphalt cement with water. The asphalt sets when the water
evaporates.
Assimilation -----The ability of a body of water to purify itself of pollutants.
ASTM -----American Society for Testing Materials.
Attenuation -----1. Reduction in magnitude, as in the lowering of peak runoff discharge rates, in the
case of dry ponds. 2. Reduction of contaminant concentrations, as in the action of
biodegradation in wetlands or bioretention facilities.
Auxiliary Spillway -----A spillway whose control section is at a lower elevation than the emergency
spillway and higher than the principal spillway.
Available Soil Moisture -----That portion of moisture in soils that can be readily absorbed by plant
roots.
B
b -----The symbol of Bottom Width in Channel Calculations.
B-Horizon -----The lower soil zone that is enriched by the deposition or precipitation of material from
the overlying A-Horizon.
Back Blade -----The process whereby a bulldozer or grader with its blade in the down position moves
backward in order to smooth out a soil surface.
Backfill -----The process of filling an excavated hole with soil, gravel, rock, or other material.
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