Accretion : The build up of land or beach by sand movement to shore.

Advance (of a beach) : A continuing seaward movement of the shoreline. Also PROGRESSION.

Aggradation : The general smoothing of the earth’s surface by deposition due to air or aquatic transport of material.

Alongshore : Parallel to and near the shoreline; same as LONGSHORE.

Amplitude : The vertical distance that a wave causes water to be displaced from a mean value.  An ocean wave has an amplitude equal to the vertical distance from STILLWATER LEVEL to wave crest.

Aqueous : A substance that is dissolved in water.

Aquifer : An underground geological (rock) formation that can store and transmit large amounts of water.

Atmospheric Emissions : The release or discharge of fumes, dust or particulates into the air.

Attenuation : A lessening of the AMPLITUDE, or wave height, as a wave increases its distance from origin or the depth of water increases.

Awash : Being intermittently washed over by waves.

Background Concentration (Level) : The concentration of any substance that would normally be found in an area.  This amount is used as a basis of comparison in identifying contamination levels.

Backshore : That zone of the shore or beach that is only acted upon by waves during severe storms, especially when combined with exceptionally high water. See Figure 1 located at the end of the glossary.

Bathymetry : The measurement of depths of water in oceans, seas, and lakes; also information derived from such measurements.

Beach Erosion : The carrying away of beach materials by wave action, currents, or wind.

Beach Width : The horizontal dimension of the beach measured normal to the shoreline.

Bench Mark : A permanently fixed point of known elevation.

Bluff : A high steep bank or cliff.

Breakdown Products : Most contaminants are chemical combinations of specific substances.  Contaminants are degraded, or separated, into individual substances called Breakdown Products through chemical or physical means.

Breakwater : A structure that protects a shoreline, harbor, anchorage, or basin from waves.

Bulkhead : A shoreline protection structure or partition intended to retain land from sliding into a water body.

CERCLA : Comprehensive Environmental Response, Compensation and Liability Act of 1980.

Chart Datum : The plane or level to which soundings (or elevations) are referenced (usually LOWER WATER DATUM). To provide a safety factor for navigation, some level lower than the mean lake level is generally selected for hydrographic charts such as MEAN LOW WATER or MEAN LOWER LOW WATER.

Climatology : The science of studying climatic conditions.  Climatic conditions studied are usually within a region of the earth over an extended period of time.  Conditions include temperature, wind velocity, and precipitation.

Contour : A line on a map or chart representing points of equal elevation with relation to a DATUM.  Contours are considered ISOBATHs when the connecting points of equal depth are below the CHART DATUM.

Convergence : As two waves merge the wave height will increase totaling the height of both individual waves.  Increased wave heights will also occur when the depth of water in which they are travelling decreases. The opposite of DIVERGENCE.

Current : The part of a fluid body (air or water) that moves continuously in a certain direction.

Datum : A chosen point used as a basis for calculating or measuring.

Deflation : The removal of loose material from a beach or other land surface by wind or wave action.

Diffraction (of water waves) : When waves are interrupted by a barrier, such as a breakwater, and energy is transmitted laterally along a wave crest.

Divergence : When a wave separates creating two waves, the wave height of each wave will decrease as the distance between them increases. Decreased wave heights will also occur as the depth of water in which they are travelling increases. The opposite of CONVERGENCE.

Downdrift : The predominant direction of movement of shoreline materials, such as sand.

Drift (noun) : The speed at which floating material is moved.

Drift Current : A broad, shallow, slow-moving lake current. Opposite of STREAM CURRENT.

Element : All substances are made up of elements, which are the basic components, or parts, of all materials.  Elements cannot be separated or broken down into smaller units by ordinary chemical means. (Examples include:  calcium, carbon, mercury, etc.)

Erosion : The wearing away of land by the action of natural forces such as wind, waves or other natural forces.  On a beach erosion occurs when material is taken away by wave action or by DEFLATION.

Escarpment : A more or less continuous line of cliffs or steep slopes facing in one general direction which are caused by erosion or faulting.  Also SCARP.

Exposure Route : The way in which people come into contact with a substance.  The main routes are ingestion, inhalation, and absorption through the skin.

Flanking : The effective redirection of waves around an object.  The result of flanking can be exacerbated erosion on the sides of a shoreline structure as seen below.

Foredune : The front dune immediately behind the backshore.

Freeboard : The additional height of a structure above the high water level used in a design to prevent overflow.  Also, at a given time, the vertical distance between the water level and the top of the structure.

Gaseous : The vapor form (for example, air) of any substance.

Generating Area : In wave forecasting, the continuous area of water surface over which the wind blows in nearly a constant direction.  Sometimes used synonymously with Fetch Length, also Fetch.

Gradient (grade) : With reference to winds or currents, the rates of increase or decrease in speed. With reference to chemicals or water levels, the difference between two concentrations or levels.  (Also, see SLOPE.)

Gravity Wave : A wave whose speed is controlled primarily by gravity. Water waves more than 2 inches long are considered gravity waves.

Groin : An impermeable wall-like structure constructed perpendicular to the shore intended to trap material or retard erosion along one part of the shoreline.

Groundwater : Water found below the ground surface in a rock or sand formations. Much of our domestic water supplies are drawn from groundwater wells.

Headland (Head) : A high steep-faced peninsula extending into a large body of water.

Height of Wave : The vertical distance between a crest and the preceding trough.  See also SIGNIFICANT WAVE HEIGHT. See Figure 2 located at the end of the glossary.

High Water Line (HWL) : The highest elevation on the shore reached during a high water event, including meteorological effects.

Hydraulically Equivalent Grains : Sedimentary particles that settle at the same rate under the same conditions.

Hydrography : A configuration of an underwater surface including its relief, bottom materials, coastal structures, etc. The description and study of seas, lakes, rivers, and other waters.

IGLD : International Great Lakes Datum.

Inorganic Substances : Materials that do not contain carbon and are generally derived from minerals.

Inshore (zone) : In beach terminology, the zone of variable width extending from the low water line to where waves end their runup of the shoreline.

Leach : The process by which substances are released from the soil by dissolving in fluids, usually rain and surface water, and are carried away. Leaching can cause hazardous substances to enter the subsurface soil, surface water, or groundwater.

Leachate : A contaminated liquid that results from water collecting contaminants as it trickles through a substance containing contaminants, agricultural pesticides, fertilizers or waste.

Littoral Drift : The drifting of shoreline material.

Littoral Zone : A coastal region, especially the region between the high water mark and low water mark.

Longshore : Parallel to or running along the shoreline.

Low Water Datum : An approximation of the mean low water level that has been adopted as a standard reference plane. See Also CHART DATUM.

Lower Low Water (LLW) : The average height of lower low water levels over a 19-year period.  Also Mean Lower Low Water

Maximum Contaminant Level (MCL) : EPA evaluates the health risks associated with various contaminant levels to ensure that public health is adequately protected.  The MCL, as it is commonly known, is the maximum allowable concentration of a specific contaminant in public drinking water considered to be safe by the EPA.

Mean Low Water (MLW) : The average height of low water levels over a 19-year period.

Mean Lower Low Water (MLLW) : The average height of lower low waters levels over a 19-year period. Frequently abbreviated to LOWER LOW WATER (LLW).

Media : Air, water and soil are the three environments, or media, subject to regulatory action by EPA.

Metabolism : A chemical and physical process in which substances (such as glucose) are transformed into energy and waste products.

National Priorities List (NPL) : EPA’s list of uncontrolled or abandoned hazardous waste sites identified for possible long-term clean up under the Superfund Program.

NDBC : The National Data Buoy Center. The NDBC is an agency within the National Weather Service (NWS) of the National Oceanic and Atmospheric Administration (NOAA). Data from the NDBC can be used to track and predict wave patterns.

NOAA : The National Oceanic and Atmospheric Administration.

NWS : The National Weather Service.

Organic : Any compound that contains carbon, naturally derived from animal or plant sources.

Over Topping : When a solid flow of water is carried over the top of a structure (for example, a revetment) by waves.

Particulates : Extremely tiny fragments or small pieces of material which can be carried by the wind.

Planform :

Proprietary Chemical : Chemicals that have been developed under the protection of a patent.

Reflection, Wave : That part of a wave that is returned back toward the water body or bounced from a steep beach, barrier, or other reflecting surface.

Refraction (of water waves) : The process by which the direction of a wave moving in shallow water at an angle to the contours is changed.  The part of the wave advancing in shallower water moves more slowly than that part still advancing in deeper water, causing the wave crest to bend towards alignment with the underwater contours. The bending of wave crests by currents.

Resonance : The phenomenon of amplification of a free wave of a system by a wave with exactly an equal period.

Retrogression (of a beach) : A continuing movement of the shoreline towards land. A net landward movement of the shoreline over a specified time. Also recession.

Revetment : A facing of stone, concrete, etc., built to protect a scarp, embankment, or shore structure against erosion by wave action or currents.

Riparian : Pertaining to the banks or shoreline of a body of water. Also, the rights of a person owning land containing or bordering on a watercourse or other body of water in or to its banks, bed, or water.

Riprap : A layer, facing, or protective mound of stones placed to prevent erosion, SCOUR, or sloughing of a structure or embankment; also the stone used.

Risk Assessment : An evaluation process that determines the projected health effects caused by exposure to a specific contaminant based on (1) an evaluation of the characteristics and concentration of the contaminant, (2) the exposure pathways present, (3) the projected incidence of human exposure, and (4) toxicity (poisonous) factors.

Runup : The rush of water up a structure or beach after the breaking of a wave on a shoreline or object.  The amount of runup is the vertical height above the stillwater level that the rush of water reaches.  Also UPRUSH.

SARA : The Superfund Amendments and Reauthorization Act of 1986

Scarp : A more or less continuous line of cliffs or steep slopes facing in one general direction which are caused by erosion.  Also ESCARPMENT.

Scour : Removal of underwater material by waves and currents, especially at the base or toe of a shore structure.

Sediment Budget : To account for all sediments that flow into and out of a defined system, such as a park beach. Sediments that flow in are considered to come from a ‘SOURCE’ while all sediments leaving the system are considered to be lost to a ‘SINK.’  Accounting for all sources and sinks provides a sediment budget.

Sedimentation : The settling of solids out of water by gravity.

Set of Current : The direction toward which a current flows.

Setup, Wave : An increase in the surface water elevation near shore due to wind.

Sink : A generalized term for anything that takes away mass or volume (such as sediments) from a defined system. Often used to determine contaminate or sediment budgets.

Slope : The amount an elevation will change in the vertical direction versus the horizontal distance traveled over the surface.  Commonly described as rise over run. Usually expressed as a ratio, such as 1:25 or 1 to 25, indicating 1 unit of vertical rise in 25 units of horizontal distance; or in a decimal fraction (0.04); degrees (2° 18’); or percent (4%).

Soluble Compounds : Substances that can be dissolved in water.

Sorption : A process by which contaminants are held by a surface or medium.

Source : A generalized term for anything that gives mass or volume (such as sediments) to a defined system. Often used to determine contaminate or sediment budgets.

Stillwater Level : The water surface elevation if all wave action were absent.

Stream Current : A narrow, deep, and swift current, such as the Gulf  Stream.  Opposite of DRIFT CURRENT.

Superfund Program : The program that funds the EPA solid waste emergency and long-term removal and remedial activities.

Swash : The rush of water onto the beach face following the breaking of a wave.  Also UPRUSH, RUNUP.

Toe : Reinforcement at the base of a shoreline structure that helps to prevent bottom SCOUR.

Topography : The 3-dimensional configuration of a surface, including its relief, the position of its streams, roads, buildings, etc.

Toxic : Acting as a poisonous or hazardous substance; having poisonous or harmful qualities.

Toxicity : A measure of the poisonous or harmful nature of a substance.

Turbidity Curtain : An in-water “silt fence” designed to prevent the flow and/or washing of disturbed debris to a water source.

Updrift : The direction opposite the predominant movement of shoreline materials, such as sand

Uplift : The force pushing up on the base of a structure or pavement due to water pressure.

Uprush : The rush of water up a structure or beach from the breaking of a wave.  Also RUNUP.

Vapor : The gaseous form of a substance that can be carried in the air as a result, inhalation may become an exposure route.

Volatalization : The process by which liquid substances is transformed to a gas.

Wave : A ridge, deformation, or undulation of the surface of a liquid.  See Figure 2 located at the end of the glossary.

Wave Age : The ratio of wave speed to wind speed.

Wave Direction : The direction from which a wave approaches.

Wave Forecasting : The theoretical determination of future wave characteristics, usually from observed or predicted meteorological data.

Wave Reflection : That part of a wave that is returned back toward the water body or bounced from a steep beach, barrier, or other reflecting surface.

Wave Train : A series of waves from the same direction.

Wave Trough : The lowest part of a wave form between successive crests.  Also part of a wave below stillwater level.  See Figure 2 located at the end of the glossary.

Wavelength : The horizontal distance between similar points on two successive waves measured between the crest of each wave.  See Figure 2 located at the end of the glossary.

Wind Setup : An increase in the surface water elevation near shore due to wind.

WIS : Wave Information Study. A computer model used by the United States Army Corp. of Engineers to predict wave direction and size based on windspeeds measured at multiple airports surrounding the Great Lakes.