Acre foot: The amount of water that
would cover one acre at the depth of one foot (325,900 gallons).
Aquatic Insect: Insect species whose
larval and juvenile forms inhabit streams or lakes.
Benthic: Bottom-dwelling. Aquatic
organisms that live on or in the stream bed.
Carrying Capacity: The maximum number
of organisms that a particular habitat can support over the long-term.
Limited by food, shelter, spawning or nesting area, rearing cover, etc.
Coagulation: The addition of coagulant
particles to water to aid in removing suspended particles in the drinking
Collector: Aquatic insect that feeds
by gathering detritus, bacteria, etc.
Community: The plants and animals
that interact in a habitat.
Cover: Overhanging or instream structures
such as tree roots, undercut streambanks, boulders, or gabions that
offer protection from predators or shelter from strong currents.
Current: Sometimes refers to the
swiftest part of a stream flow; otherwise refers to the velocity of
the flow, measured in feet or meters/seconds (ft/s, m/s).
Decomposer: A type of stream organism,
such as bacterium or fungus, that processes dead organic matter.
Detritivore: Animal that feeds primarily
Detritus: Nutritious mixture of
digested and partly digested organic matter, bacteria, fungi, feces,
Discharge: The amount of water flowing
past a given point on a stream. Measured in cubic feet (or cubic meters)
per second (cfs;cm/s).
Dissolved Oxygen: Oxygen dissolved
in water. The amount depends on temperature of the water, plant photosynthesis,
plant and animal respiration, and physical aeration caused by tumbling.
Measured in parts per million (mg/L).
Doctrine of Prior Appropriation:
ÒFirst in Time, First in Right.Ó
Ecosystem: The interacting plants,
animals, and physical components (sunlight, soil, air, water) of an
Effluent: Waste liquid flowing into
a river or lake from a house, industry, sewage treatment plant, or other
Erosion: Detachment of soil particles
by water, wind, ice, gravity or organisms.
Evapotranspiration: Collective term
for evaporation and plant transpiration, which return water vapor from
the earthÕs surface to the atmosphere.
Fecal Coliform Bacteria: Bacteria
common to the intestinal tract of mammals. Indicates biowaste from livestock
or humans and may be a sign of disease-causing pathogens.
Filtration: The filtering out of
particles during the purification process for drinking water.
Food Web: A community of organisms
that are dependent on one another for food.
Gradient: The slope of the streambed
Groundwater: Water that sinks into
the ground and collects over impermeable rock. It then flows laterally
toward a stream, lake, or ocean. Wells tap it for our use. Its surface
is called the Òwater tableÓ.
Habitat: The specific environment
in which an organism lives and on which it depends for food and shelter.
Hardness: The concentration of calcium
or magnesium in water; affects the availability of nutrients and toxic
substances to stream organisms.
Headwaters: Small streams and creeks
at the uppermost end of a river system.
Hydrologic Cycle (Water Cycle):
Water in its various manifestations as vapor evaporated from oceans,
lakes, streams, and plants; rain and snow; snowpack or glacier; groundwater
or surface runoff; and finally as streams and rivers returning to the
Larva (plural: larvae): Immature
insect of the type that pupates into adult form.
Limiting Factor: A condition or
situation that limits size of a population (e.g., spawning or rearing
habitat, food, cover, migration barrier, disease, predation).
insects found under rocks in creekbeds.
Meander: The tendency of moving
water to form S-shaped curves (meanders).
Minimum Instream Flow: Water rights
that are used to ensure enough water remains in the stream to support
Monitor: To track a characteristic,
such as dissolved oxygen, nitrate level, or fish population, over a
period of time using uniform methods to evaluate change.
Non-point Source: Diffuse, overland
runoff containing pollutants. Includes runoff collected in storm drains.
Nymph: Immature form of insects
such as stoneflies and mayflies that do not pupate.
Parameter: A variable quantity -
such as temperature, dissolved oxygen, or fish population Ñ that
is the subject of a survey of sampling routine.
Periphyton: Plants, usually algae,
attached to rocks or other instream objects.
pH: Measure of acidity. Stands for
Òthe negative logarithm of free hydrogen ionsÓ in water.
Water of low pH is acidic; high pH is basic, or alkaline.
Point Source: A pipe that discharges
effluent into a stream or other body of water.
Population: A discrete portion of
a species that interbreeds. If isolated from other populations of the
species for long periods of time, it may evolve into a separate race
Predator: A carnivorous animal that
preys on other animals.
Reach: A stream section with fairly
Riffle: A shallow, gravelly area
of streambed with swift current. Used for spawning by salmonids and
other fishes. The most productive area of a stream.
Riparian Zone: The border of a stream
or river above its banks; affects the stream and is affected by it.
Sediment: Fine soil or mineral particles.
Side Channel: A flood channel or
abandoned stream channel connected to a stream or river at periods of
high flow. Serves juvenile fish as rearing habitat and refuge from floods.
Siltation: The process of becoming
clogged with fine sediments.
Storm Drain: A system of gutters,
pipes, or ditches used to carry stormwater runoff into sewers or streams.
Stormwater Runoff: Surface water
that washed off land after a rainstorm. In developed watersheds it flows
off roofs and pavements into storm drains which may feed directly into
the stream; often carries concentrated pollutants.
Suspended Sediments: Fine mineral
or soil particles that remain suspended by the current until deposited
in areas of weaker current. They create turbidity and, when deposited,
can smother fish eggs or alevins. Can be measured in a laboratory as
ÒTotal Suspected SolidsÓ (TSS).
Toxic: Poisonous, carcinogenic,
or otherwise harmful to life.
Turbidity: A measure of material,
usually fine sediments, suspended in water; determined by passing light
through a water sample.
Urban Stream: A stream passing through
urbanized area. Impacted by urban stormwater runoff; often channelized;
sometimes trashed. Usually an excellent candidate for rehabilitation.
Watershed: The entire drainage area
or basin feeding a stream or river. Includes surface water, groundwater,
vegetation, and human structures.
Water Rights: Legally established
right to appropriate water from a given stream.
Water Table: The upper surface of
the groundwater; the level below which the soil is saturated with water.
Its depth is influenced by rainfall and by human development (wells,
drainage ditches, loss of wetlands, etc.).
Wetlands: Habitats flooded with
shallow water all or part of the year. Can be identified by unique plants
which have adapted to oxygen-deficient (anaerobic) soils. Wetlands influence
stream flows and water quality.