MORE WORDS TO KNOW ...
Hydrology - the science that encompasses the occurrence , distribution , movement and properties of the waters of the earth and their relationship with the environment within each phase of the hydrologic cycle .
Impaired – detrimental effect on the biological integrity of a water body caused by an impact that prevents attainment of the designated use .
Impervious cover – a material on the land surface that water cannot infiltrate . It is usually material like concrete , asphalt , metal or brick .
Instream flows - An amount of water running in a river , usually measured by the volume moving down the channel in a specified amount of time ( discharge ). A variety of instream flows are required to maintain a healthy river and to support fish and wildlife in and along waterways .
Intermittent stream – has flowing water during certain times of the year . During dry periods , these streams may not have flowing water . These streams are often called dry streams , creeks or washes .
Native riparian tree – naturally occurring tree along stream banks which is adapted to the local conditions .
Non-native species ( or exotic species ) – a species that humans have introduced to a new ecosystem .
Non-point source pollution – pollution that cannot be traced back to a single source . Non-point source pollution usually enters the water as overland flow , rather than from a single pipe .
Percolate – when liquid water flows through the soil due to the force of gravity . Water loses gravitational energy when it percolates through the soil .
Perennial stream – has flowing water year-round during a typical year .
Pesticide – any substance or mixture of substances intended for preventing , destroying , repelling or mitigating any pest . Under United States law , a pesticide is also any substance or mixture of substances intended for use as a plant regulator , defoliant or desiccant .
Pool – a deeper , quieter area in a stream where there is no obvious current .
Primary contact recreation – Activities that are presumed to involve a significant risk of ingestion of water ( wading by children , swimming , water skiing , diving , tubing , surfing and the following whitewater activities : kayaking , canoeing and rafting ).
Rain garden – a planted depression that is designed to collect and absorb rainwater runoff , reducing the amount of pollution and sediment reaching creeks and streams .
Run ( in stream or river ) – A reach of stream characterized by fast-flowing , low-turbulence water .
Runoff – see Stormwater runoff .
Riffle – a shallow part of a stream that is characterized by turbulent flow of water over stones 2-10 inches in diameter .
Riparian corridor – the zone of land adjacent to a stream , river or other water course .
Sanitary sewer – an underground system of pipes , manholes and tunnels that transports waste to a wastewater treatment plant for treatment and eventual re-use or release into creeks .
Sedge – grass-like plants often found growing on wet ground or in water , usually with triangular stems .
Sediment – material that is laid down or deposited by water , air or ice .
Scum - the light solids ( oil , grease , hair , etc .) that accumulate on the surface of the water in a septic tank .
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