Water Quality: My Place on a Stream
Module 3

Lesson 3 - Glossary
Acknowledgement: Taken from "Living on the Land 2001"

Aggradation: The process of building up or elevating a stream bed or floodplains by depositing sediment.

Bank Armoring: Coarse, erosion-resistant materials such as large rocks, that protect underlying finer and more erodible material.

Channelization: The practice of straightening a waterway to remove meanders and make water flow faster. Sometimes concrete or riprap is used to line the sides and bottom of the constructed channel.

Coarse Woody Debris: Logs, branches, or tree limbs that have or could become part of the fabric of a channel, causing water to mix and slow in velocity, and sediment to become stored in the valley bottom.

Degradation: The process of a stream cutting deeper into the streambed.

Deposition: The process by which eroded sediment settles out of the water column onto the floodplain or the stream bed or banks.

Dredge: To mechanically remove accumulations of sediment or other materials from within a stream channel or other water body, often for the purpose of channelization.

Engineering: Designing or creating a designed structure. In streams, engineering often creates a new form, different from what was natural or pre-existing.

Ephemeral Stream: A stream that flows only in response to storm events, not from ground water discharge.

Erosion: The wearing away, detachment and movement of soil and other materials, generally by wind or water, through natural and/or unnatural causes.

Floodplain: 1. (geomorphology) The flat area adjacent to a river or stream that is formed by the stream or river. 2. (hydrology) The area flooded by an event of some specific return frequency.

Flood Insurance: An insurance program often required for those living in the path of 100-year floods.

Gully: A channel that has downcut so that water no longer floods over adjacent lands except perhaps in very rare and big floods.

Headcut: A place where water in a channel falls over the edge of a somewhat erosion-resistant material and onto material that is so erodible that the location of the falls moves, or cuts, headward up the channel.

Headgate: A structure designed to divert a measured amount of water from a channel into an irrigation ditch.

Incision: Process of the channel cutting into the bed of the valley.

Levee: A berm or wall that keeps a stream away from some portion of its floodplain when the stream flow exceeds channel capacity.

Livestock: Cows, horses, sheep, goats, llamas, or other animals that are kept for pleasure or economic gain.

Meander: An S-shaped curve or bend in a stream. Meanders help reduce the velocity of water in a stream by decreasing slope, or fall per unit distance.

Natural Restoration: The reformation of natural features through natural processes such as erosion, deposition, and revegetation.

Natural Tendencies: Changes that occur within natural channels or ones recovering on their own from disturbance.

Pesticide: A chemical used to kill or damage pests of any kind. An herbicide is a type of pesticide used to kill plants or weeds.

Piecemeal Engineering: Engineering that does not consider off-site effects and is not part of an integrated plan.

Perennial Stream: A stream that flows year-round.

Riparian Vegetation: Vegetation that is adapted to the moisture conditions adjacent to a stream.

Riprap: Stones or some energy-absorbing engineered material used to armor a streambank or channel by blanketing its surface.

Roughness: A feature that mixes water and slows its average velocity or dissipates energy by creating friction.

Sediment Detention Basin: A pond that allows water to stand relatively still while sediment settles out.

Stream Power: The ability of a stream to transport particles out of the watershed. This depends on stream slope and discharge.

Water Quality Standards: Specific numerical or narrative limits placed on the concentration of various constituents in water, or on other physical or biological characteristics of aquatic systems. The standards are based upon the beneficial uses of the water.

Watershed: An area of land from which rain and/or snowmelt discharges to a stream, river, or other water body.

Watershed Condition: The ability of a watershed to capture, store, and safely release water to a stream.

Wetland: An area of land that is saturated at least part of the year by water. Wetlands are delineated with specific criteria related to their hydrology, soils, and vegetation. Wetlands associated with coastal salt water include salt marshes, tidal basins, marshes, and mangrove swamps. Inland freshwater wetlands include swamps, marshes, seeps and bogs (lentic wetlands) and streams, rivers, and springs (lotic wetlands).

Wildlife Habitat: The place in the landscape where wildlife are supported because of specific characteristics such as the type and structure of vegetation, food, water, etc. For example, some riparian wildlife habitats are favored by certain birds due to the presence, size, structure, and abundance of willows.

Willows: Shrubs or trees of the genus Salix. They are known for their water-loving habit, their common long, pointed, and narrow leaf shape, and their unique but not showy flowers.

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