Glossary of terms


ADA: Association of Drainage Authorities


Biodiversity Action Plan (BAP): A Biodiversity Action Plan provides a framework for habitat and species conservation, both highlighting threats and issues, and encouraging methods of best practice


Berm: A horizontal shelf cut into an embankment to break the continuity of a long slope to reduce erosion and provide beneficial habitat


Brownfield site: A redevelopment site, usually within an urban area


Catchment: The area adjacent to a watercourse from which water drains into it


Control Structure: A device to limit the flow of water Gravity System: A drainage system whereby flow is caused by the action of gravity


Culvert: A closed conduit or structure used to convey water through an obstruction for example an embankment or roadway.


DEFRA: Department for Environment, Food and Rural Affrairs


Dredge: The deepening of a watercourse through the removal of sediment or deposited material


GIS: Geographical Information System


Greenfield site: A new development, usually at the edge of an urban area


Headwall: A retaining wall placed either end of a pipe or culvert


IDB: Internal Drainage Board


Land Drainage Act: The Land Drainage Act was passed in 1991 and requires that watercourses are maintained by their owner so that the free flow of water is not impeded


Lead Local Flood Authority (LLFA): The body responsible for developing, maintaining, applying and monitoring a strategy for local flood risk management in its area

(For more information on the role of LLFAs please see DEFRA’s Local Authority Factsheet


Outfall: The point where water discharges from a pipe, channel, or other conduit


Pile: A long, slender structure driven into a bank to improve its support and stability


Right to Accretion: A right to material deposited by the watercourse


Right to Boomage: A right of entry onto riperian land for the purpose of fastening of booms and boom sticks


Riperian: Anything connected with, or adjacent to a watercourse


Runoff: Water from precipitation that flows off a surface to reach a drain or sewer


Screen: A device used to retain or remove solids flowing in drains


Sluice: A sliding gate or door, which controls the flow of water (i.e. flow when the gate is open, no flow when the gate is closed)


Sustainable Drainage Systems (SuDS): Drainage techniques believed to be environmentally beneficial or causing little or no long-term detrimental impact


Weed Cutting: The process of removing weed from the channel


Weir: An overflow structure across a channel used to control upstream surface levels, reduce erosion or divert flow