Abstraction – the act of pumping or removing water from the groundwater or a river
Aquifer – underground, permeable rock which can act as a store of water
Canalising – converting a river into a canal-like waterway, usually by installing artificial banks and/or bed and straightening the channel
Dredging – scooping or digging out of the river bed to deepen the channel
Groundwater – underground water, held in saturated rock or soil
Invasive non-native species – animals or plants found outside their natural distribution, and which cause harm to the environment, people and/or the economy
Macrophytes – a non-microscopic aquatic plant growing in or near water
Meander – a bend in a river. Meanders add variety to a river's flow, and can promote erosion and deposition of sediment
Morphology – the form and structure of the river channel, e.g. the straightness or depth of the channel
pH – a measure of how acidic a liquid is. pH 7 is neutral - below this, the lower the pH value, the more acidic it is; the higher the pH, the more alkaline it is.
Physical modifications – alterations which people have made to the form of the river. They include weirs, and straightening, widening, deepening, canalising or dredging the channel
Phytobenthos – microscopic plants that live attached to the river bed, or to rocks, stones or large plants within the river channel
Pollution – contaminants which affect the river's water quality. Examples would be from herbicides, pesticides, organic and artificial fertiliser, sediment, sewage or heavy metals.
Riffle – a stretch of relatively shallow, fast-flowing water
Winterbourne – a stream which flows only after prolonged heavy rainfall leading to high groundwater levels, usually in the winter months