Glossary

Aquifer: An underground bed of saturated soil or rock that yields significant quantities of water.

BOD: Biochemical oxygen demand serves as a measure of the amount of oxygen used by micro-organisms in breaking sewage down into stable compounds.

Catchment: the smallest watershed area, usually defined as the area that drains an individual site, such as a school or small neighborhood, to its first intersection with a stream.

Drainage Basin: A large watershed encompassing the watersheds of many smaller rivers and streams and draining to a major river, estuary or lake.

Ecosystem: A community of living organisms and their interrelated physical and chemical environment; also, a land area within a climate.

Evapotranspiration: The return of moisture to the atmosphere from the evaporation of water from soil and transpiration from vegetation.

Groundwater: Water found in spaces between soil particles underground (located in the zone of saturation).

Hydrologic Cycle: Also known as the water cycle, this refers to the paths water moves through in its various states–vapor, liquid, and solid–as it moves throughout Earth’s systems (oceans, atmosphere, groundwater, streams, etc.).

Impervious surface coverage: Surfaces that do not allow stormwater runoff (water) to seep into the ground, such as sidewalks, roadways, driveways, and rooftops.

Integrated pest management (IPM): A system of reducing pest problems using environmental information along with variable pest control methods. These methods include physical, mechanical, biological, cultural and chemical means of reducing pests.

Macro invertebrate: An animal that lacks a backbone (invertebrate) and is large enough to be seen with the naked eye. They are a good indicator of water quality, because the most sensitive can only survive in areas of high water quality (e.g., the stonefly is highly sensitive to pollution and is only found in streams with high water quality).

Non-Point Source Pollution: Widespread overland runoff containing pollutants; the contamination does not originate from one specific location, and pollution discharges over a broad land area. Water pollution that cannot be traced to a specific source.

Pesticides: Chemical compounds designed to control and kill pests. The term pesticides includes herbicides (chemicals to kill weeds), insecticides (chemicals to kill insects), and fungicides (chemicals to kill fungus), etc.

Point Source Pollution: Pollutants discharged from any identifiable point, including pipes, ditches, channels, sewers, tunnels and containers of various types.

Sedimentation: The settling of soil particles (sediment) to the bottom of a waterway.

Sewage: The waste and wastewater produced by residential and commercial sources and discharged into sewers or septic systems.

Stormwater runoff: Precipitation that flows overland to surface streams, rivers, and lakes (either directly or through storm sewers).

Sub-watershed: The land area draining to the point where two smaller streams combine together to form a larger, single stream.

Supernatant: The usually clear liquid overlying material deposited by settling, precipitation or centrifugation.

Terminal Moraine: Large mound or hill of loose sand and gravel deposited by the leading edge of a glacier.

Transpiration: The process by which water absorbed through plant roots is returned to the atmosphere from the leaves.

Tributary: A river or stream flowing into a larger river or stream.

Watershed: The land area from which surface runoff drains into a particular stream channel, lake, reservoir, or other body of water.

 

Copyright 2000. Great Swamp Watershed Association.