General Glossary Homepage

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A

Algae

Simple rootless plants that grow in bodies of water in relative proportion to the amount of nutrients available.

Algal Bloom

An unusual, sudden or excessive abundance of algae. Algal blooms can adversely affect water quality.

Alkaline

A material with a pH of more than 7.0 Capable of neutralizing acid and producing hydroxyl (OH) ions in solution.

Alkalinity

Capacity of a lake to neutralize acid.

Allochtonous Material

Aquatic Life

Plants or animals living in water.

Aquifer

An underground layer of sand, gravel or rock that stores or conveys water below the surface of the soil.

Aquitard

An underground bed or layer of soil, rock or clay that is too dense to allow easy passage of water.

Autotochonous Material

B

Baseflow

The stream discharge composed of ground water drainage and delayed surface drainage.

Basin

A tract of land in which the ground is broadly tilted toward a common point. Water that falls onto any portion of the basin is carried toward the common point by a single river system.

Bedrock

The solid rock found on the surface of the land or just below the soil.

Bioaccumulation

Build up of toxic substances in fish flesh. Toxic effects may be passed on to humans eating the fish.

Biodegradable

Able to be broken down into simpler products by microscopic plants and animals.

Biological Oxygen Demand

The amount of oxygen required by aerobic microorganisms to decompose the organic matter in sample of water. Used as a measure of the degree of water pollution.

C

Carbon Dioxide (CO₂)

A heavy, colorless, odorless gas, present in the atmosphere or formed by the burning of fuels containing carbon. Carbon dioxide is also exhaled by animals and used by plants in photosynthesis.

Catchment Area

Channel

Chloride

Common anionic form of chlorine which carries one net negative charge. A common anion in many waters.

Chlorophyll a

The main pigment in algae. It is used to measure aquatic productivity.

Cobble

Conservation

The protection or wise use of natural resources, such as forests, rivers and fuels, to ensure their continuation.

Contaminate

To make impure or unsafe by contact with potentially harmful substances.

D

Decomposition

The process by which a substance is broekn down into component parts of basic elements. Food and other plant and animal matter decompose under the proper conditions of light, air and moisture.

Depth

Discharge

Drift

Deposits of boulders, gravel, sand, clay or till moved and deposited by a glacier or the water from a melting glacier.

E

Ecoregion

Areas of relative homogeneity based on land use, soils, topography and potential natural vegetation.

Ecosystem

A community of interaction among animals, plants, and microorganisms, and the physical and chemical environment in which they live.

Effluent

Liquid flowing out of a system, such as a discharge of liquid waste from a factory or water leaving a sewage treatment plant.

Erosion

The wearing away of land surfaces by the action of wind or water.

Eutrophic

A lake that has a high level of plant nutrients and biological productivity and a low oxygen content.

Eutrophication

The aging process by which lakes are fertilized with nutrients. Natural eutrophication will very gradually change the character of a lake. Cultural eutrophication is the accelerated aging of a lake as a result of human activities.

F

Fines

Floodplain

The aging process by which lakes are fertilized with nutrients. Natural eutrophication will very gradually change the character of a lake. Cultural eutrophication is the accelerated aging of a lake as a result of human activities.

Flow

G

Geomorphological Characteristics

Refers to the size and shape of the river channel and adjacent flood plain. Habitat rehabilitation projects typically seek to alter geomorphologic characteristics so channels and aquatic habitat are more like those that existed prior to management. Geomorphology is the study of the shape of the surface of the earth, and the processes that form it.

Ground Water

Underground water in an aquifer, used for drinking water in 75 percent of Minnesota households. The subsurface water supply in the saturated zone below the level of the water table.

H

Heavy Metals

Metals with high molecular weights that are of concern because they are generally toxic to animal life and human health if naturally occurring concentrations are exceeded. Examples include, arsenic, chromium, lead and mercury.

Herbicides

Chemicals used to kill undesirable vegetation.

Hydrogeologic Study

A study of an area's geology, ground water and ground water movement.

I

Invertebrate Drift

Ion

    An electrically charged atom or group of atoms.

J

K

L

Leachate

Liquids that have percolated through a soil that carry substances in solution or suspension. Liquids can be rain water or snow melt that enter soil and carry contaminates from buried wastes. Leachate can seep into ground or surface water, or pool on or around a landfill.

M

Macrohabitat 

A contiguous volumetric region in a river channel that is characterized by similar depth, velocity, and substrate with dimensions on the order of bankfull channel width. This definition is consistent with that of Hawkins and others (1993) of "semi-discrete areas of relatively homogeneous depth and flow that are bounded by sharp physical gradients" Macrohabitats often are associated one-to-one with particular biological sampling gear.

Monitoring Well

A well installed at a site to determine the direction of ground water flow, levels of contamination and other ground water characteristics.

N

Natural Cycle

A series of events in nature that repeat over and over, usually involving a complete process of growth or action. Examples include: the oxygen, nutrient, hydrologic and mineral cycles.

Nonpoint Source

Polluted runoff -- nutrients and pollution sources not discharged form a single point: e.g., runoff from agricultural fields or feedlots.

Nutrient

A substance that provides food or nourishment, such as usable proteins, vitamins, minerals or carbohydrates. Fertilizers, particularly phosphorus and nitrogen, are the most common nutrients that contribute to lake eutrophication and nonpoint source pollution.

O

Organism

A living body made up of cells, tissues and organs.

P

pH Scale

A measure of acidity, with 7 being neutral. Numbers under 7 are acidic and numbers over 7 are alkaline.

Phosphate

An essential nutrient containing phosphorus and oxygen. Phosphate is often a critical nutrient in lake eutrophication management.

Photosynthesis

The process by which green plants produce oxygen from sunlight, water and carbon dioxide.

Phytoplankton

Algae -- the base of the lake's food chain, it also produces oxygen.

Plume

The path and form taken by contaminated ground water as it moves from the source.

Point Source Pollution

Pollution arising from a well-defined origin, such as a discharge from an industrial plant.

Pollutant

A substance that pollutes air, water or land.

Pollution

The contamination of soil, water or air by the discharge of potentially harmful substances.

PPB

Parts per billion. Ten ppb means ten parts of a contaminant to one billion parts of water.

Q

R

Reach 

Reaches are defined as a contiguous length of river with one or more repeating sequences of similar channel units, or macrohabitats. In small rivers, a minimum reach would have a single riffle-pool sequence; in a large, regulated river a minimum reach would be considered a cross-over pool sequence, or a single navigation pool. Reaches can contain multiple repeating sequences as long as the channel units and macrohabitats contained within them are within a specified range of variation. Practical identification of maximum lengths of reaches is based on recognition of where hydraulic properties change substantially.

Respiration

Oxygen consumption.

Runoff

That portion of precipitation or irrigation water that flows off a field or paved area and enters surface water.

S

Sedimentation

The addition of soils to lakes, a part of the natural aging process, making lakes shallower. The process can be greatly accelerated by human activities.

Sediment

Solid material that is in suspension, is being transported, or has been moved from its original location by air, water, gravity or ice.

Sediment Yield

The quantity of sediment arriving at a specific location.

Seepage

Percolation of water through the soil from unlined canals, ditches, laterals, watercourses, or water storage facilities.

Sewage

The organic waste and wastewater that comes from homes, farms and businesses.

Shading

Sheet Erosion

The removal of a fairly uniform layer of soil material from the land surface by the action of rainfall and surface runoff.

Sinuosity

A measure of channel curvature, usually quantified as the ratio of the length of the channel compared to the length of a straight line along the valley axis. Sinuosity ratios vary with the chosen length of the straight line.

Soil

The top layer of the earth's surface, composed primarily of rock, minerals and decomposed matter from dead plants or animals.

Soil Borings

Borings into the earth that bring up samples of soil or rock from various levels to study for composition or contamination.

Stream Channel

A channel with flowing water for at least part of the year.

Substrate Composition

Surface Water

Aboveground water, such as streams, rivers and lakes.

Suspended Solids

Small particles that hang in the water column and create turbid, or cloudy conditions.

T

Thalwag

The line connecting the lowest or deepest points along the riverbed, usually identical to the center of the navigation channel.

Total Suspended Solids

A measure of the material suspended in wastewater. Total suspended solids (TSS) cause: 1) interference with light penetration, 2) buildup of sediment and 3) potential reduction in aquatic habitat. Solids also carry nutrients that cause algal blooms and other toxic pollutants that are harmful to fish.

Transitional Upland Fringe

A portion of the upland on one or both sides of the floodplain that serves as a transitional zone or edge between the floodplain and the surrounding landscape.

Trophic Status

The level of growth or productivity of a lake as measured by phosphorus content, algae abundance, and depth of light penetration.

U

V

 Velocity

W

Water Table

The top surface of the aquifer nearest ground level.

Watershed

The surrounding land area that drains into a lake, river or river system.

Wetlands

A lowland area, such as a marsh or swamp, saturated with water. Wetlands are crucial wildlife habitat, and important for flood control and maintaining the health of surrounding ecosystems.

X

Y

Z

Zooplankton

Microscopic animals.