Erosion and Sediment Pollution Control Program Manual.pdf

APPENDIX L – GLOSSARY
NOTE – This glossary is intended to be a comprehensive directory for industry terms
for plan preparers and reviewers. Therefore, many terms found in this glossary are not
included in the manual.
A
A ----- Symbol for Area. In Runoff Calculations, it stands for Tributary Drainage Area to the BMP being
designed; in Channel Calculations, it represents the cross-sectional area of the channel,
likewise for Culvert Calculations it is the cross-sectional area of the Culvert. In Basin
Dewatering Calculations, it stands for the area of the riser perforations.
A-Horizon -----The uppermost zone in the Soil Profile, from which soluble Salts and Colloids are
leached, and in which organic matter has accumulated. It generally represents the most fertile
soil layer.
AASHTO -----American Association of State Highway and Transportation Officials.
AASHTO # 1 Stone -----A standard size range for Coarse Aggregate Stone ranging from ¾” to 4” in
diameter. (See Table 6.7)
AASHTO #57 Stone -----The standard size range for Coarse Aggregate Stone ranging from that which
passes a #8 Sieve to 1 ½” in diameter. (See Table 6.7)
ABACT -----Antidegradation best available combination of technologies
Abatement -----Reducing the degree or intensity of, or eliminating, pollution.
Abrasion -----Removal of stream bank soil as a result of sediment-laden water, ice, or debris rubbing
against the bank.
Absorption -----The process by which a liquid is drawn into and tends to fill permeable pores in a
porous body.
Abutment -----1. A retaining wall that also supports a vertical load (e.g. a bridge abutment). 2. In
dams, it is the part of a valley sidewall against which a dam is constructed.
Abutting -----In real estate, the property adjoining or bordering another property.
Accelerated Erosion -----Erosion of surface materials due to human activities at a rate that is faster
than would occur naturally. (See Introduction)
Access Road -----A roadway, either temporary or permanent, constructed for the purpose of accessing
a structure, facility, or BMP.
Acid -----A substance that releases hydrogen ions when dissolved in water. A strong acid will release a
large proportion of ions while a weak acid will release a small proportion of ions.
Acid Mine Drainage (AMD) -----A term indicating a discharge composed of leachate from a mine,
usually a surface or underground coal mine, typically characterized by low pH, high iron and
sulfate content, and high dissolved solids.
Acid Producing Materials -----Rock containing significant concentrations of pyrite, such that if
exposed to air and/or water will produce sulfuric acid.
Acid Soil -----Soil with a pH below 7.0.
Acre -----A measure of area equal to 43,560 square feet (4,046.87 square meters). One square mile
equals 640 acres.
Acre-Foot (AF) -----A unit commonly used for measuring the volume of water. It is equal to the
quantity of water required to cover one acre to a depth of 1 foot. It is equivalent to 43,560 cubic
feet (1,234 cubic meters) or 325,851 gallons.
Act 167 -----The Pennsylvania Stormwater Management Act, 32 P.S. §§ 680.1— 680.17. It provides
for the regulation of land and water use for flood control and storm water management
purposes, imposing duties and conferring powers on the DEP, municipalities and counties,
providing for enforcement, and making appropriations.
Adjudication -----A court proceeding to determine water rights for a particular stream or aquifer.
Adsorption -----The physical adherence or bonding of ions and molecules to the surface of another
molecule. The preferred process used in cleanup of environmental spills.
Aerated Concrete -----Lighter weight concrete; it has bubbles incorporated into the mix to make it so.
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