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Advection: The usually horizontal movement of a mass of water (as in an ocean current); or the transport of pollutants or plankton by such movement.

Aerial deposition: The process by which airborne toxic contaminants enter coastal waters via aerial fallout.

Aquatic biota: The flora and fauna living in the water.

Aquifier: Water bearing layer of the earth’s crust; an underground layer of unconsolidated rock or soil that is saturated with (usable) water.

Bacterial indicators: Specific bacteria whose presence can indicate the recent release of untreated wastewater and/or the presence of pathogens that are harmful to humans.

Benthic infauna: Any of a diverse group of aquatic animals that live within marine and fresh water sediments.

Best Management Practices or BMPs: An engineered structure, management activity, or a combination of, that eliminates or reduces an adverse environmental effect of a pollutant. More info here.

Biodegradable: Capable of being decomposed (broken down) by natural biological processes.

Carcinogenic: Describing a substance that can produce a cancerous growth.

Catch basin: Curbside opening that collects rainwater from streets and serves as an entry point to the storm drain system. [Photo here]

Channelization: The straightening and/or the surfacing of rivers and streams to permit water to move rapidly and/or directly downstream. See also Flood Control Channel below.

Clean Water Act: The federal water quality control law governing surface waters establishing water quality objectives, waste discharge standards, and the National Pollutant Discharge Elimination System.

Constructed wetlands: Areas that are designed and built to simulate natural wetlands and processes; consist of one or more shallow depressions or cells built into the ground with level bottoms allowing the flow of water to be controlled within the cell, and from cell to cell; roots and stems of the wetlands plants form a dense mat where biological and physical processes occur to treat wastewater. [more info]

Culvert: Concrete or corrugated steel drainage pipes used to convey water under structures such as roads, highways, or bridges.

DDT: Also known as "Dichloro-Diphenyl-Trichloroethane." The first chlorinated hydrocarbon insecticide. It has a half-life of 15 years and can collect in fatty tissues of certain animals. EPA banned registration and interstate sale of DDT for virtually all but emergency uses in the United States in 1972 because of its persistence in the environment and accumulation in the food chain.

Detention basin: Reservoir designed to reduce or slow the rate of flow in an open drainage facility.

Discharge: A release of any kind liquid into a water body.

Direct discharge: Also known as Point Source emissions; direct disharge refers to any intentional release of wastes through direct pumping or pipeline discharge.

Dredging: Removal of sediment from the bottom of water bodies. This can disturb the ecosystem and causes silting that kills aquatic life. Dredging of contaminated sediments can expose biota to heavy metals and other toxins.

Dry weather diversion(s): Also known as Low Flow Diversions, these devices allow dry-weather storm drain flows to be diverted to the sewer system for treatment but are stopped during storm events. These diversions serve to significantly reduce the amount of untreated dry weather runoff reaching coastal waters.

E. coli: A bacterium (Escherichia coli) occurring in various strains that can live as harmless inhabitants of the human lower intestine, or can produce a toxin causing intestinal illness. Public Health officials use E. Coli to indicate the presence of pathogenic bacteria in water.

Effluent: Wastewater, treated or untreated, that flows out of a treatment plant (e.g. Hyperion Treatment Plant), sewer, or industrial outfall.

El Niño: Or El Niño Southern Oscillation (ENSO), is an anomalous oceanographic and atmospheric event in the equatorial Pacific Ocean that usually occurs every three to seven years and is characterized by an increase in the sea-surface temperature in the eastern equatorial Pacific Ocean. ENSO is thought to be responsible for anomalous climatic conditions spanning most of the globe. Many of the resulting impacts of El Niño are negative, causing drought, famine, and floods.

More info can be found at the National Oceanic and Atmospheric Administration web site.

Enterococcus: Any of a genus (Streptococcus) of nonmotile, usually parasitic, bacteria occurring in the intestine. This bacteria is regularly measured in the Bay to provide an indication of the presence of disease-causing bacteria.

Estuary: Body of water at the lower end of a river and which is connected to the ocean or semi-enclosed by land. In an estuary, sea water is measurably diluted by freshwater from the land. A coastal region of convergence or interaction between rivers and nearshore ocean waters where tidal action and river flow create a mixing of freshwater and saltwater. These areas may include bays, mouths of rivers, salt marshes, and lagoons. The Ballona Lagoon is just one example.

Eutrophic: Eutrophic conditions occur when the concentration of nutrients in rivers, estuaries, and other bodies of water increases and results in anaerobic (lack of oxygen) conditions in the water column. The increase of nutrients stimulates algae "blooms" as the algae decays and dies, the availability of dissolved oxygen is reduced resulting in high BOD; as a result, creatures living in the water accustomed to aerobic conditions perish.

Fecal coliform: Bacteria found in the intestinal tracts of humans and warm-blooded animals. The presence of high numbers of fecal coliform bacteria in a water body can indicate the recent release of untreated wastewater and/or the presence of animal feces. While these bacteria do not directly cause disease, high quantities of fecal coliform bacteria suggest the presence of disease causing agents. The presence of fecal contamination is an indicator that a potential health risk exists for individuals exposed to this water.

"First Flush": The first big rain after an extended dry period (usually summer) which flushes out the accumulated pollutants in the storm drain system and carries them straight to the ocean. Graphic or more info here.

Floatables: Pollutants that float on the water surface such as pieces of trash and debris.

Flood control channel: Open waterway that is designed to carry large amounts of rain water. These structures are often lined with concrete to help control flood waters. Examples: Ballona Creek and the Los Angeles River. Graphic

Geographic Information System (GIS): A computer and software system that links spatial or locational information with descriptive information.

Greywater: Domestic wastewater from all sources except toilets.

Groundwater: The supply of freshwater found beneath the Earth’s surface, usually in aquafiers, which is often used to supply wells and springs.

Gutter: The edge of a street (below the curb) designed to drain water runoff from streets, driveways, parking lots, etc. into catch basins. Area formed by the curb and the street to prevent flooding by channeling runoff to the storm drains. Graphic

Heavy metals: Naturally occurring metal elements including cadmium, chromium, lead, mercury, arsenic, nickel, etc. Can also be found in sewage sludge and urban runoff. Many are toxic at low concentrations and tend to accumulate in the food chain.

Household Hazardous Waste: Also known as "Residential Special Materials, are common everyday products that people use in and around their homes—including paint, paint thinner, herbicides, and pesticides that, due to their chemical nature, can be hazardous if not properly disposed. Los Angeles residents are strongly encouraged to dispose of these materials by contacting LARecycles.org.

Illegal discharge: Any nonpermitted disposal into the storm drain system for which a person or business does not have a permit.

Illicit connection: Any connection to a storm drain system for which there is no permit or is used for an illegal discharge.

Impervious surface: Paved surface or other land cover that does not allow water to percolate into the ground.

Intertidal habitat: The area between land and sea which is regularly exposed to the air by the tidal movement of the sea. Marine organisms that inhabit the intertidal zones have to adapt to periods of exposure to air and to the waves created by wind, which makes it the most physically demanding of the marine habitats. The shore zone between the highest and lowest tides.

Mass loading: The mass of a pollutant entering an area per unit of time.

Non-Point Source Pollution: (NPS) pollution which does not come from a single, identifiable point but from a number of points that are spread out and difficult to identify and control. Includes materials that wash from roofs, streets, yards, driveways, sidewalks as well as from agriculture, erosion, construction and mining. Collectively, this is the largest source of stormwater pollution. More info here.

Organic compound: Naturally occurring (animal or plant-produced or synthetic) substances containing mainly carbon, hydrogen, nitrogen, and oxygen.

Outfall: Opening at the end of a storm drain system that allows water to flow into a channel, lake, river, bay or ocean. Graphic

Pathogens: Microorganisms (e.g., bacteria, viruses, or parasites) that can cause disease in humans, animals and plants.

Plume: A visible or measurable discharge of a contaminant from a given point of origin. Can be visible, sediment, or invisible, such as thermal in water, or visible in the air as, for example, a plume of smoke.

Percolation: Process where surface waters are absorbed through the soil into ground water.

Point Source Pollution: Pollution from a single identifiable source such as a smoke stack or sewage-treatment plant. Most of this pollution is highly regulated at the state and local levels.

Pollutants: Materials can include, but are not limited to, trash, paper, plastics, cleaning chemicals, animal waste, yard wastes, used oil, fertilizers, pesticides, sediment, metals, fuels, solvents, detergents and fecal coliform.

Pollution: A human or naturally caused change in physical, chemical, or biological conditions that results in an undesirable effect on the environment.

Primary treatment: The first process in the wastewater treatment process where some of the suspended solids and organic matter are removed through sedimentation. Common usage of this term also includes preliminary treatment to remove wastewater constituents that may cause maintenance or operational problems in the system (i.e., grit removal, screening for trash and debris, oil and grease removal, etc.). See also Hyperion Sewage Treatment Plant.

Receiving water(s) or receiving body(ies):

Red Tide: A noticable red or brown discoloration of sea water caused by excessive amounts of nutrients that lead to the growth of microscopic algae. These algae decay and leads to loss of clarity and oxygen depletion, which may kill or restrict fish, shellfish and other marine organisms. Graphic

Riparian: Areas adjacent to rivers and streams with a differing density, diversity, and productivity of plant and animal species relative to nearby uplands.

Runoff: (Also known as Urban Runoff) Water that flows over land surfaces and does not percolate into the ground. Also see "Runoff pollution" below.

Runoff pollution: Water from rain (also called stormwater, urban runoff, and storm drain pollution), irrigation, garden hoses or other activities that picks up pollutants (cigarette butts, trash, automotive fluids, used oil, paint, fertilizers and pesticides, lawn and garden clippings and pet waste) from streets, parking lots, driveways and yards and carries them through the storm drain system and straight to the ocean.

Secondary treatment: A type of wastewater treatment used to convert dissolved and suspended pollutants into a form that can be removed, producing a relatively highly treated effluent. Secondary treatment normally utilizes biological treatment processes followed by settling tanks and will remove approximately 85% of the BOD and TSS in wastewater. Secondary treatment for municipal wastewater is the minimum level of treatment required by the Clean Water Act. See also Hyperion Sewage Treatment Plant.

Sedimentation: The deposition or accumulation of sediment.

Sewer system: The drainage conveyance that takes wastewater from home plumbing systems (toilets, showers, sinks, washers, etc) and takes it to a sanitary sewer plant (Hyperion Treatment Plant for the greater LA area). More info here.

Source control: Reducing the amount of materials entering the waste stream from a specific source. Action to prevent pollution at its origin.

Storm drain system: A network of conveyance systems which includes catch basins, grates, gutters, underground pipes, creeks or open channels designed to transport rain from developed areas and discharged to a receiving body of water. Storm drains can carry a variety of pollutants such as sediments, fecal waste, metals, bacteria, oil, and antifreeze that enter the system through runoff, deliberate dumping, or spills. More info here.

Suspended solids: The small particles of solid matter in any water sample which are suspended. The term is usually used for solids in the effluent discharged from sewage treatment.

Stream: (Also arroyo, barranca and creek) Small natural waterway originating from underground springs, snow melt, runoff or other natural sources which drains to lakes, rivers, channels or the ocean.

Tertiary treatment: Full disinfection of liquid waste. Methods include chlorination and ozonation. Tertiary treatment produces drinkable water and is required for discharge into fresh water bodies.

Total Maximum Daily Load (TMDL): A numerical quantification of the pollutant loading that can be received by a waterbody from all sources without exceeding state water quality standards. The TMDL consists of wasteload allocations for point source (e.g. industrial and municipal discharge), load allocations for non-point sources (e.g. agriculture, construction, siviculutre) and a margin of safety so that any additional loading, regardless of source, would not produce a violation of water quality standards. More info here.

Wastewater treatment: See primary, secondary, and tertiary treatment. See also Hyperion Sewage Treatment Plant.

Watershed: Geographic area of land from which all runoff drains into a single waterway or the total land area from which rain water drains into a particular stream, drain, or body of water; the drainage basin in the Los Angeles region are 4 primary watersheds: the Los Angeles River, the Santa Monica, and the Upper and Lower Ballona Creek Watersheds.

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Acronyms