- abandoned channel
part of a stream which has been separated from the main stream by natural or artificial means. No surface water flows in it.
Components of an ecosystem which are not living. A term often used for the result of chemical and physical impacts on organisms.
large quantity of individuals of a species present in a survey of flora or fauna
Water with a pH below 7 (elevated level of free hydrogen ions H+). See pH.
- adduction zone
area where water is collected, and where human activities are regulated to avoid pollution
an organism or tissue, requiring air for life;
a name for all the materials extracted from a river bed: sand, gravel, rocks...
chemical substances which spread on the ground for agriculture improvement
Collective name of a large group of chlorophyll-containing waterplants, comprising of seaweeds and various freshwater forms, ranging in size from single cells to long stems.
The opposite of an acid, having a pH of more than 7. An alkaline solution will react with acids to yield a salt.
1) Water with a pH above 7 (elevated level of free hydrogen ions OH-). See pH.
1) Formed by or deposited by river flow processes e.g. alluvial plains
- alluvium/fluvial sediments
Alluvium : Sediment deposited by flowing water
An order of vertebrate animals that begin life in water, but as an adult are at home both in water and on land: eg. frogs, toads, newts, salamanders...
Difference between flow during a flood and average flow rate
Living in the absence of air or free oxygen; pertaining to or caused by the absence of oxygen
General - describes conditions in water in which oxygen is absent: such conditions are fatal for many organisms, in particular for fish. Technical - conditions in water in which no oxygen is chemically available, even from compounds from which some micro-organisms can “extract” oxygen (eg. nitrates); to be distinguished from anaerobic = conditions in which dissolved oxygen is absent – anoxic conditions represent a more extreme absence of oxygen than anaerobic conditions.
Man-made modifications of the natural environment and, in particular for rivers, transformation into an artificial system
Amphibians (see definition) which do not have tails: eg. frogs, toads.
The science and practice of farming organisms that live in water, such as fish, shellfish, and algae
A geologic formation, such as fractured bedrock, sands or gravels, which holds water underground and supplies water to springs and wells; also used to refer to the water stored in such formations, that is ground water
a formation, group of formations, or part of a formation that contains sufficient saturated permeable material to yield significant quantities of water for wells and springs
Natural or artificial length of river or water, for example a secondary channel parallel to the main river, which remains connected to the river at the downstream end.
Something that is man made. (Lake, stream, dam)
- Average flow
Average annual flow (in m3/second) of a river (average flow over the whole year, taken from a number of years’ data)