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Glossary of Terms
Anadromous: Fish that move from the sea to fresh water for
reproduction.
Biotic: Something that is living, or pertaining to living things.
Canopy Cover: The overhanging vegetation over a given area.
Channel Complexity: A term used in describing fish habitat. A
complex channel contains a mixture of habitat types that provide areas
with different velocity and depth for use by different fish life stages.
A simple channel contains fairly uniform flow and few habitat types.
Channel Confinement: Ratio of bankfull channel width to width of
modern floodplain. Modern floodplain is the flood-prone area and may
correspond to the 100-year floodplain. Typically, channel confinement is
a description of how much a channel can move within its valley before it
is stopped by a hill slope or terrace.
Channel Habitat Types (CHT): Groups of stream channels with
similar gradient, channel pattern, and confinement. Channels within a
particular group are expected to respond similarly to changes in
environmental factors that influence channel conditions.
Channel Pattern: Description of how a stream channellooks as it
flows down its valley (for example, braided channel or meandering
channel).
Cohesive: When describing soil, tendency of soil particles to
stick together. Examples of soils with poor cohesion include soils from
volcanic ash, and those high in sand or silt.
Conifer: Cone-bearing tree, generally evergreen (although certain
exceptions occur), having needle-like leaves. Examples include pines,
Douglas fir, cedar and hemlock.
Connectivity: The physical connection between tributaries and
river, between surface water and groundwater, and between wetlands and
these water sources.
Cut Slope: The sloping excavated surface on the inside bank of a
road.
Debris Flow: A type of landslide that is a mixture of soil,
water, logs and boulders which travels quickly down a steep channel.
Discharge: Outflow; the flow of a stream or canal.
Downcutting: When a stream channel deepens over time.
Ecology: A branch of science that studies the inter-relationships
of organisms with their environment.
Ecological Function: A function that is the result of natural
processes (e.g. physical and biological), which create habitat,
conditions or resources (e.g. food, water) that local organisms have
adapted to and come to rely on. For example, flooding is a process that
provides habitat for wetland dependent species. Another example, certain
plants are adapted to fire and require it in order to germinate or
highly benefit from it.
Ecoregion: Land areas with fairly similar geology, plants and
animals, and landscape characteristics that reflect a certain ecosystem
type.
Evapotranspiration: The amount of water leaving to the atmosphere
through both evaporation and transpiration (i.e. through plant leaves).
Fill Slope: The outer edge of a road that extends downhill of the
road surface.
Flood Attenuation: When flood levels are lowered by water storage
in wetlands, lakes or reservoirs to lessen or diminish their severity.
Floodplain: The flat area adjoining a river channel constructed
by the river in the present climate, and overflowed at times of high
river flow.
Fluvial Fish: Fish that rear in larger rivers and spawn in
smaller river tributaries.
Fry: The early life stage of salmon and trout after the yolk sac
is absorbed.
Gaging Station: A selected section of a stream channel equipped
with a gage, recorder or other facilities for measuring stream
discharge.
Geographic Information System (GIS): A computer system designed
for storage, manipulation and presentation of geographical information
such as topography, elevation, geology, etc.
Habitat: The place or type of site where a plant or animal
naturally or normally lives and grows.
Hardness: A measure of the calcium and magnesium concentrations
in water; used to select the appropriate criteria for heavy metals.
Hardwood: Non cone-bearing tree, always deciduous (i.e. loses its
leaves every fall). Examples include maple, oak and willow.
Hydric Soils: a soil that is saturated, flooded or ponded long
enough during the growing season to develop anerobic (no oxygen)
conditions in the upper part of the soil profile.
Hydrologic Cycle: The circulation of water around the earth, from
ocean to atmosphere and back to the ocean again.
Hydrology: The study of surface and ground water movement from the
atmosphere and through the soil.
Impairment: When violation of exceedence criteria (e.g. water
quality criteria) or poor instream habitat conditions indicates that a
beneficial use of surface water is harmed.
Impervious Surface: Surface (such as pavement) that does not
allow, or greatly decreases, the amount of infiltration of precipitation
into the ground.
Infiltration: The rate of water movement from the atmosphere into
the soil.
Invertebrate: Animals with no vertebrate (i.e. backbone); they
can be microscopic or visible to the human eye. Examples include
insects, worms, snails and freshwater mussels.
Juvenile: The early life stage of salmon or trout, usually the
first and second years.
Large Woody Debris (LWD): Logs, stumps, or root wads in the
stream channel, or nearby. These function to create pools and cover for
fish, and to trap and sort stream gravel.
Low Flows: The minimum rate of stream flow for a given period of
time.
Mass Wasting: Down slope transport of soil and rocks.
Meandering: When a stream channel moves from side to side across
its valley (e.g. snake like pattern.
Morphology: A branch of science dealing with the structure and
form of objects. Geomorphology as applied to stream channels refers to
the nature of landforms and topographic features.
Oxbow Lake: A bow-shaped river bend that has been isolated from
its former channel.
Peak Flow: The maximum instantaneous rate of flow during a storm
or other period of time.
Precipitation: The liquid equivalent of rain, snow, sleet or
hail.
Rain-on-Snow Event: When snowpacks are melted by warn rains,
causing peak flow events.
Recruitment Potential for Large Woody Debris: The amount or size
of large trees in a riparian area that could potentially fall in (i.e.
be recruited) to the stream channel. Mechanisms for recruitment include
small landslides, bank undercutting, wind throw during storms,
individual trees dying of age or disease and transport from upstream.
Resident Fish: Non-migratory fish that remain in the same stream
network their entire lives.
Riparian Area: Area bordering streams and rivers.
Riparian zone: An administratively defined distance from the
water’s edge that can include riparian plant communities. Alternatively,
an area surrounding a stream, in which ecosystem processes are within
the influence of stream processes.
Riparian Vegetation: Vegetation growing on or near the banks of a
stream or other body of water in soils that are wet during some portion
of the growing season. Includes areas in and near wetlands, floodplains,
and valley bottoms.
Salmonid: Fish of the family Salmonidae, including salmon, trout,
char, whitefish, ciscoes and grayling. Generally the term refers to
salmon, trout and char.
Sediment: Fragments of rock, soil and organic material
transported and deposited into streambeds by wind, water or gravity.
Spawning: Term used to describe the reproduction of fish;
involves females laying eggs in gravel or mud at the bottom of a lake or
stream and male fertilizing eggs.
Species: A biological classification comprised of related
organisms or populations potentially capable of interbreeding. Species
names and immediately preceded by genus names (e.g. Homo sapiens, where
Homo is the genus name and sapiens is the species name; This is the
scientific name for humans).
Splash Damming: Historical practice where a small dam was built
across a stream to impound water and logs. The dam was then removed
(usually with explosives) to release the impounded logs and water,
causing scouring of stream substrate downstream.
Stream Reach: A section of stream possessing similar physical
features such as gradient, flow and confinement.
Substrate: Mineral or organic material that forms the bed of a
stream.
Surface Runoff: Water that runs across the top of the land
without infiltrating the soil.
Upland Vegetation: Vegetation typical for a given region, growing
on drier upland soils. The same plant species may grow in both riparian
and upland zones.
Acronyms
ACE: Army Corps of Engineers
BLM: Bureau of Land Management
cfs: cubic feet per second
CHT: channel habitat type
dbh: diameter at breast height
ESA: Endangered Species Act
GIS: Geographic Information System
LWD: large woody debris
NTU: nephalometric turbidity unit
NWI: National Wetlands Inventory
ODA: Oregon Department of Agriculture
DEQ: (Oregon) Department of Environmental Quality
ODF: Oregon Department of Forestry
ODFW: Oregon Department of Fish and Wildlife
ONHP: Oregon Natural Heritage Program
OWEB: Oregon Watershed Enhancement Board
OWRD: Oregon Water Resources Department
SWCD: Soil and Water Conservation District
SSCGIS: State Service Center for GIS
USGS: U.S. Geological Survey |
