English Glossary

Below you find the English glossary.

English	Explanation
Alluvial deposits	Sediments deposited by modern rivers and streams
Alluvial river	River with a bed consisting of sediments deposited by this river and still actively remolded by erosion and sedimentation
Alluvium	Sediment deposits
Anabranched river	River consisting of a network of channels separated by large islands that are usually vegetated
Anadromous	Adjective indicating fish that spawn in fresh water after spending most of their lives and becoming mature in the sea. See also
Aquifer	Water-bearing layer of porous subsurface material that can yield usable quantities of water
Backswamps	Wetlands in the lowest areas of the valley floor away from the main channel, storing fine-grained suspended-load sediments
Backwater effect	Influence from downstream conditions on water levels and flow velocities
Bank	Lateral channel boundary
Bankfull discharge	Discharge at which water levels reach the top of the river banks
Bar	Submerged or emerged bedform of sand, gravel, or other unconsolidated material, built in shallow water and much longer than the water depth
Base flow	Sustained low flow in a stream, mostly fed by groundwater discharge
Bathymetry	Spatial distribution of water depths below an agreed plane of reference water levels. As this plane has a slope in rivers, bathymetry should not be confused with
Bed level	Elevation of bottom of river or stream above a horizontal datum
Bedload	Sediment transported by rolling, sliding or jumping over the bed
Bed-material load	Transport of sediment that is also found in the river bed. It can be transported as both and
Bedrock	Consolidated subsurface material that underlies soils or other unconsolidated material
Bed shear stress	Tangential forces per unit bed area exerted by the flow on the river bed, as a measure of flow strength. See also and
Bed topography	Spatial distribution of bed elevations with respect to a horizontal datum, not to be confused with
Bench	Sediment deposition unit along a bank face. Also
Benthic	Living at or in the bottom of a fresh or salty body of water. Opposed to
Benthos	Plants and animals that live in, on or attached to the bottom of water bodies
Berm	Sediment deposition unit along a bank face. Also
Biogeographical region	Relatively large area that contains characteristic assemblages of natural communities and species that are the product of broad environmental influences and common evolutionary and immigration history. See
Bivalve	A mollusk with two shells, for instance a clam or a mussel
Boulders	Rock fragments larger than 200 mm in diameter
Braided river	River consisting of a network of smaller channels separated by small and often temporary non-vegetated islands called braid bars
Buffer strip	Vegetation along a stream left intact after logging or land clearing, preventing fine sediment from entering into the stream
Cascade	Stream bed covered with disorganized boulders in steep confined channels
Catadromous	Adjective indicating fish that spawn in the open sea after spending their lives and becoming mature in fresh water. See also
Catchment	Area of land drained by a river and its tributaries. Also or . Catchment is a spatial unit within the multi-scale of hydromorphological processes and forms
Chute channel	Channel across a bar or floodplain, shortcutting the flow in the main channel
Clay	Mineral soil particle smaller than 0.002 mm in diameter
Cobbles	Rock fragments between 63 mm and 200 mm in diameter
Crenal	Zone of stream source in longitudinal habitat zonation, also . See also and
Crevasse	Breach in natural levee
Crevasse splay	Local accumulation of sand or gravel, deposited by water escaping from the channel through a
Crossing	Relatively shallow zone between two consecutive bends in navigable rivers. Also
Cross-over	Relatively shallow zone between two consecutive bends in navigable rivers. Also
Crustacean	Invertebrate animal (without backbone) with a hard exoskeleton (external support or protection of the body) and at least five pairs of jointed legs on the thorax
Current	Movement of water in a water body
Datum	Reference elevation level, for instance mean sea level
Degradation	In hydromorphology: Lowering of bed elevation by erosion or removal of sediment. In ecology: Damaged condition of habitat
Discharge	Volume of water that flows through a section per unit of time
Drainage basin	Area of land drained by a river and its tributaries. Also or . is a spatial unit within the multi-scale of hydromorphological processes and forms
Dune	Bedform with a height in the order of tens of percent of the water depth. Two-dimensional dunes have long crests perpendicular to the flow. Three-dimensional dunes have short crests.
Ecoregion	See and .
Emergent plant	Plant rooted in shallow water with much of the stem and most of the leaves above the water
Eurytopic	Adjective for aquatic species that tolerate both stagnant and flowing water conditions. See also and
Floodplain	Land bordering a river or a stream, built up of sediments from overbank flows and subject to inundation at floods
Flow resistance	Forces opposing the discharge of water. A low flow resistance implies high flow velocities and small water depths. A high flow resistance implies low flow velocities and high water depths.
Flow velocity	Distance travelled by flowing water per unit time, as a measure of flow strength. See also and
Geomorphic unit	Area containing a landform created by erosion or deposition inside or outside the river channel. Also , or . Geomorphic unit is a spatial unit within the multi-scale of hydromorphological processes and forms
Glide	Zone of relatively shallow flow as an intermediate feature between shallower riffles and deeper pools, similar to the somewhat steeper
Gravel	Rock fragments between 2 and 63 mm in diameter
Habitat	Place where a particular species or life stage lives and grows. Essentially, it is the (mostly physical) environment that surrounds a species population or age group
Hydraulic roughness	Parameter governing
Hydraulic unit	Spatially distinct patch of relatively homogeneous surface-flow and substrate character. Hydraulic unit is a spatial unit within the multi-scale of hydromorphological processes and forms
Impoundment	Structure built to maintain a desired water level
Infauna	Benthic animals that burrow into the substrate
Invertebrates	Animals without a backbone
Island	Landform surrounded by areas of the channel bed and emerged at bankfull stage
Krenal	Zone of stream source in longitudinal habitat zonation, also . See also and
Landscape unit	Portion of a catchment with similar landscape morphological characteristics. Also physiographic unit. Landscape unit is a spatial unit within the multi-scale of hydromorphological processes and forms
Levee	See . Levee can also refer to a man-made dike along the Loire river in France or along North-American rivers that belonged to French Louisiana between 1682 and 1803, such as the Mississippi river
Limnetic	Related to the environment of lakes and ponds. Adjective for aquatic macroinvertebrates that prefer standing water
Limnophilic	Adjective for aquatic species that prefer stagnant water. See also and
Lotic	Related to fast-moving water, such as in most streams and rivers
Macroinvertebrates	Animals without backbones (“invertebrates”) that are large enough to be seen with the naked eye (“macro”, larger than 0.5 mm)
Macrophyte	All aquatic higher plants, mosses and characean algae, but excluding single-celled phytoplankton and diatoms
Macrozoobenthos	Aquatic macroinvertebrates living at or in the bottom
Meandering river	River with a single channel and a larger than 1.5
Measure	See and
Mesohabitat	Spatially distinct patch of relatively homogeneous patches serving species or life stages as . See
Microhabitat	Spatially distinct patch of uniform substrate, plant cover or physical structure which is relevant for species, e.g. as spawning or feeding substrate
Mitigation measure	Activity to reduce the impact of a pressure
Mollusks	Unsegmented invertebrate animals (without a backbone) that possess an external or vestigial calcium carbonate shell
Morphological unit	See
Mud	Loose slushy fine sediment consisting of clay, silt, fine sand, and organic material. Often water-formed and deposited on the bottom of lakes, rivers and estuaries
Natural levee	Elevated feature along river channel, composed of sediments deposited by overbank flows leaving the main channel
Oxbow lake	Lake formed when a river meander is cut off from the main channel
Pebble	Gravel particle
Pelagic	Living and feeding in the water column. Opposed to
Physiographic unit	See
Phytoplankton	Microscopic plants that float or drift almost passively in water
Point bar	Bar along the inner bank of a river bend
Pool	Relatively deep, still section in a river or stream. Pools alternate with or in gravel-bed rivers and with or in navigable rivers
Potamal	Zone of lowland rivers in longitudinal habitat zonation. See also or and
Pothole	Deep circular hole scoured in bedrock as a result of abrasion by transported particles trapped in the hole
Pressure	In hydromorphology: Force per unit area exerted on a surface by the weight of the water above that surface. In the Water Framework Directive: Direct environmental effect of a driver such as agriculture, industry, hydropower generation or navigation
Rapids	Stream bed with boulders organized in irregular transverse lines (ribs), in steep confined channels
Reach	Section of river along which boundary conditions are sufficiently uniform for the river to maintain a near-constant internal set of process-form interactions. Reach is a spatial unit within the multi-scale of hydromorphological processes and forms
Region	Relatively large area underleying similar broad influences of climate, relief, tectonic processes, etc. Also or . Region is a spatial unit within the multi-scale of hydromorphological processes and forms. It typically contains characteristic assemblages of natural communities and species.
Restoration measure	Activity to improve the status of degraded waters, be it by improving water quality or by changing hydromorphological conditions
Rheophilic	Adjective for aquatic species that prefer flowing waters. See also and
Rhithral	Zone of streams in longitudinal habitat zonation, identical to the zone of trout and grayling. See also or and
Ridge	Old incorporated in the floodplain as the channel migrated away
Riffle	Zone of relatively shallow and rapid flow in gravel-bed rivers
Riparian	Related to zone adjacent to a stream or river with a high density, diversity, and productivity of plant and animal species compared to nearby uplands
Ripple	Small bedform of a few centimetres high, with a long crest perpendicular to the flow
River element	Part of river environment including individuals and patches of sediment, plants, wood, etc. Also . River element is a spatial unit within the multi-scale of hydromorphological processes and forms.
River sector	See
River segment	Section of river subject to similar valley-scale influences and energy conditions. Also river sector. River segment is a spatial unit within the multi-scale of hydromorphological processes and forms
Run	Zone of relatively shallow flow as an intermediate feature between shallower riffles and deeper pools, similar to the somewhat flatter
Sand	Mineral soil particle between 0.063 mm and 2.0 mm in diameter
Scour	Local removal of sediment from the stream bed by flowing water
Scroll bar	Elongated raised feature on top of a
Sediment	Solid matter eroded, transported or deposited in rivers
Sediment yield	Amount of sediment eroded per unit land area in a river catchment
Silt	Mineral soil particle between 0.002 mm and 0.063 mm in diameter
Sinuosity	Ratio between the distance measured along the channel and the distance measured in the direction of the overall planimetric course or meander belt axis
Specific stream power	per unit channel width, as a measure of flow strength
Step	Steep accumulation of boulders and cobbles across a channel, generally with a pool downstream that is scoured by flow plunging over the step
Stream power	Rate of energy dissipation per unit downstream length, as a measure of flow strength. See also and
Stressor	Pressure in the sense of a direct environmental effect of a driver
Subreach	See
Suspended load	Sediment transported in the water column, kept from settling by upward turbulent motions of the water. It can consist of both and
Swale	Depression between adjacent that are old
Terrace	Abandoned inactive floodplain perched above contemporary channel and floodplain
Thalweg	Line connecting the deepest points of consecutive cross-sections
Thread	Channel in river typologies. A single-thread river has only one channel in each cross-section. A multiple-thread has more than one channel in each cross-section
Wandering river	River with a single channel that locally splits into two channels, as a transitional form between meandering rivers and braided rivers
Washload	Sediments much finer than those in the river bed, transported without dependence on flow strength
Water body	Distinct and significant volume of water
Water depth	Height of water column. Elevation difference between water level and bed level
Water level	Elevation of water surface above a horizontal datum
Watershed	Area of land drained by a river and its tributaries. Also or . is a spatial unit within the multi-scale of hydromorphological processes and forms