Ambient Monitoring - Monitoring program with fixed station networks and intensive surveys and producing chemical, physical, and biological analyses. Ambient monitoring deals with conditions in the aquatic environment--streams, lakes, bays, estuaries, and oceans. By contrast, effluent (discharge) monitoring involves sampling and analysis of wastewater.

Antidegradation - A policy designed to prevent deterioration of existing levels of good water quality.

Bioaccumulation - The accumulation of contaminants in the tissues of organisms through any route, including respiration, ingestion, or direct contact with contaminated water, sediment, pore water, or dredged material. Such processes can result in levels of pollutants in tissues of aquatic organisms far higher than in the surrounding water.

Designated Uses - Uses that society, through state and federal governments, determines should be attained in the waterbody. Examples include warmwater aquatic ecosystems, public water supply, and recreational fishing.

Effluent Guidelines - National standards for wastewater discharges to surface waters and publicly owned treatment works (municipal sewage treatment plants). EPA issues effluent guidelines for categories of existing sources and new sources under Title III of the Clean Water Act. The standards are technology based (i.e., they are based on the performance of treatment and control technologies); they are not based on risk or impacts upon receiving waters.

Ephemeral Streams - Ephemeral waterbodies are streams, ponds, wetlands, etc. that contain water only a fraction of the time. Vernal pools and desert washes are examples. Sometime such waters are called "intermittent". As a general rule, a waterbody is NOT excluded from the CWA definition of "waters of the U.S., simply because it is intermittent.

Feeding Guilds - The grouping of animals according to the feeding strategies they employ, whether they remain stationary and filter food out of water that passes over specialized body parts that serve as nets or sieves, dig in the bottom sediments, or chase after other animals.

Generalists - A species that can live in many different habitats and can feed on a variety of different organisms.

Nonpoint Source (NPS) Pollution - Pollution that , unlike pollution from industrial and sewage treatment plants, comes from many diffuse sources. NPS pollution is caused by rainfall or snowmelt moving over and through the ground. As the runoff moves, it picks up and carries away natural and manmade pollutants, finally depositing them into lakes, rivers, wetlands, coastal waters, and even our underground sources of drinking water. Loadings of pollutants from NPS enter waterbodies via sheet flow, rather than through a pipe, ditch or other conveyance.

Point Source of Pollution - Discrete conveyances, such as pipes or man made ditches that discharge pollutants into waters of the United States. This includes not only discharges from municipal sewage plants and industrial facilities, but also collected storm drainage from larger urban areas, certain animal feedlots and fish farms, some types of ships, tank trucks, offshore oil platforms, and collected runoff from many construction sites.

POTW - Publicly Owned Treatment Works (POTW) [40 CFR 403.3(o)] - A treatment works as defined by Section 212 of the CWA, which is owned by the state or municipality (as defined by Section 502(4) of the Act). This definition includes any devices or systems used in the storage, treatment, recycling, and reclamation of municipal sewage or industrial wastes of a liquid nature. It also includes sewers, pipes or other conveyances only if they convey wastewater to a POTW treatment plant. The term also means the municipality as defined in Section 502(4) of the CWA, which has jurisdiction over the indirect discharges to and the discharges from such a treatment works.

Specialist - A species with a very narrow range of habitat or food requirements.

Total Maximum Daily Load (TMDL) - A calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards, and an allocation of that amount to the pollutant's sources.

Trophic Levels - The energy levels or steps in a food chain or food web, i.e., primary producer, primary consumer, secondary consumer, tertiary consumer, and so forth.

Water Quality Criteria - levels of individual pollutants or water quality characteristics, or descriptions of conditions of a waterbody that, if met, will generally protect the designated use of the water.

Water Quality Standards - Includes three major components: designated uses, water quality criteria, and antidegradation provisions.

Waters of the United States - As defined in the CWA, "waters of the United States" applies only to surface waters, rivers, lakes, estuaries, coastal waters, and wetlands. Not all surface waters are legally "waters of the United States." Generally, those waters include the following:

• All interstate waters;
• Intrastate waters used in interstate and/or foreign commerce;
• Tributaries of the above;
• Territorial seas at the cyclical high tide mark; and
• Wetlands adjacent to all the above.

Wetlands - Lands where saturation with water is the dominant factor determining the nature of soil development and the types of plant and animal communities living in the soil and on its surface (Cowardin, December 1979). Wetlands vary widely because of regional and local differences in soils, topography, climate, hydrology, water chemistry, vegetation, and other factors, including human disturbance. Indeed, wetlands are found from the tundra to the tropics and on every continent except Antarctica.

For regulatory purposes under the Clean Water Act, the term wetlands means "those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs and similar areas."