Part 2: Civil engineering — Section 2.6 Inland waters, coastal and maritime engineering pot

260 1009 canal Channel constructed to carry water, usually for navigation 2, water power or irrigation.. 260 1010 lock Enclosure on a river, canal or at the entrance to a non-tidal doc

Glossary of

Building and civil

engineering terms —

Part 2: Civil engineering —

Section 2.6 Inland waters, coastal and

maritime engineering

This British Standard, having

been prepared under the

direction of the Basic Data and

Performance Criteria for Civil

Engineering and Building

Structures Standards Policy

Committee, was published

under the authority of the

Standards Board and comes

into effect on

28 June 1991

© BSI 07-1999

The following BSI references

relate to the work on this

standard:

Committee reference BDB/3

Draft for comment 90/11090 DC

The preparation of this British Standard was entrusted by the Basic Data and Performance Criteria for Civil Engineering and Building Structures Standards Policy Committee (BDB/-) to Technical Committee BDB/3, upon which the following bodies were represented:

Association of Builders’ Hardware Manufacturers Association of Building Component Manufacturers Brick Development Association

British Precast Concrete Federation Ltd

British Standards Society Building Employers’ Confederation Building Services Research and Information Association Chartered Institution of Building Services Engineers Concrete Society

Contract Flooring Association Department of the Environment (Building Research Establishment) Department of the Environment (Property Services Agency) Federation of Civil Engineering Contractors

Fibre Building Board Organisation (FIDOR)

Gypsum Products Development Association Incorporated Association of Architects and Surveyors Institution of Civil Engineers

Institution of Highways and Transportation Institution of Structural Engineers Institution of Water and Environmental Management National Council of Building Material Producers National Federation of Roofing Contractors National House-building Council

Royal Institute of British Architects Stone Federation

Timber Trade Federation Water Companies Association Water Services Association of England and Wales

The following bodies were also represented in the drafting of the standard, through subcommittees and panels:

British Railways Board Department of Transport National Rivers Authority

Amendments issued since publication

Amd No Date Comments

7254 August 1992 Indicated by a sideline in the margin

Committees responsible Inside front cover

260 5 Irrigation and land drainage 9

260 51 Types of irrigation and systems 9

260 52 Factors and requirements 10

260 93 Operations 24

Basic Data and Performance Criteria for Civil Engineering and Building Structures Standards Policy Committee.

A general introduction to and explanation of this glossary is given in Part 0 of

BS 6100, which itemizes the Parts, Sections and Subsections into which this glossary is divided and provides a general alphabetical index of all the terms in the Sections and Subsections already published Those using individual Sections and Subsections of this glossary are urged to consult Part 0 when doing so.The other Sections of this Part are as follows:

2.1 Structural design and elements2.2 Substructures Earthworks Foundations Tunnels2.3 Superstructures Bridges Large span structures2.4 Highway and railway engineering

2.5 Hydraulic engineering and construction work2.7 Public health Environmental engineering2.8 Pipelines and ducts

Terms are listed alphabetically in the index and are referred to by numbers which are found against the terms in the body of the Subsection They are arranged in

a classified order, each term having an individual number consisting of seven digits in two parts, the first of three digits, the second of four The first three digits represent the number of the Part, Section and Subsection The fourth digit represents the group of terms, the fifth digit represents the subgroup of terms, and the last two digits represent the place within the subgroup

Alternative terms are given in medium type below the preferred terms with their status indicated by “deprecated” These terms are not individually numbered but are included in the index with a reference to the preferred term Terms of more than one word, e.g “brushwood fender” are written in a direct style, not as

“fender, brushwood” The inverted term is included in the index with reference to the direct term

Italicized words indicate terms that are defined elsewhere in this Subsection

A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible for their correct application

Compliance with a British Standard does not of itself confer immunity from legal obligations.

No Term Definition

260 1 Base terms

260 1001 precipitation Water derived from atmospheric vapour and deposited on a

surface as mist, rain, hail, sleet and snow or dew.

260 1002 watercourse Route, usually in the form of a natural depression, along

which water flows by gravity

260 1003 channel Natural or man-made open passage to convey or contain

water

260 1004 drainage Removal of surplus water

260 1005 drain Pipeline or similar conduit, usually underground, or channel

that conveys foulwater, waste water, surface water or other

unwanted liquids

260 1006 discharge Volumetric flow rate

260 1007 headworks Intake and associated works at the upstream end of a water

engineering scheme

260 1008 irrigation Artificial distribution of water to land, usually for growing

crops

260 1009 canal Channel constructed to carry water, usually for navigation

(2), water power or irrigation.

260 1010 lock Enclosure on a river, canal or at the entrance to a non-tidal

dock, with movable watertight gates through which vessels

pass and proceed from one water level to another

260 1011 bank Strip of land that forms the edge of a river, canal or reservoir.

260 1012 bed Nominally horizontal or slightly sloping portion of a

watercourse or area of ground under a body of water that is

for most or all of the time covered by water

260 1013 berth Place where a vessel can be moored, usually for loading and

unloading cargo or passengers

260 1014 dock Basin for shipping.

260 1015 harbour Natural or artificially sheltered area of water where ships

can lie

260 1016 wave Oscillation of water level propagated along the surface

260 1017 tide Periodic rising and falling of water that results from the

gravitational attraction of the moon and the sun and other astronomical bodies acting upon the rotating earth

260 1018 aqueduct (1) Conduit for conveying water over long distances

260 1019 well Hole, usually vertical, excavated or drilled into the ground for

the extraction or observation of water, oil or gas

260 2 Surface water and groundwater

260 21 Precipitation

260 2101 rain Precipitation in the form of liquid water drops that have a

diameter greater than 0.5 mm

260 2102 rainfall Amount of precipitation expressed as a depth usually related

to a particular time of aggregation, for example daily rainfall.

260 2103 intensity of rainfall Rate of precipitation expressed as a depth in unit time, for

example, millimetres per hour

260 2104 isohyet Line on a map joining places with equal rainfall.

260 2105 interception Process by which precipitation is retained by and later

evaporated from a structure or vegetation and is thus prevented from reaching the ground

260 22 Surface water

260 2201 run-off Discharge of surface water that results from precipitation.

260 2202 storm run-off Run-off due to rain.

260 2203 snow melt Run-off due to melting snow.

260 2204 frazil ice

slush ice

deprecated

Ice formed, as colloidal crystals, in a watercourse when the

temperature of the entire body of water flowing along it is reduced to 0 °C

260 2206 peak flow Maximum discharge during a particular flood event or over a

specified period of time or a fluctuating flow

260 2207 design storm Rainstorm parameters adopted for the design of water

engineering construction works

260 2208 design flood Flood parameters adopted for the design of water engineering

construction works

260 2209 spate

freshet

deprecated

Sudden short-lived increase in discharge.

260 2210 catchment area Area of land that drains naturally to a given point on a river.

260 2211 sewage catchment Area of land that drains to a single sewage treatment works

Boundary between catchment areas.

260 2214 spring Natural outflow of water from the ground

260 2215 lake

mere, loch, lough, linn, tarn

regional

Large inland body of water

260 2216 pond Small shallow inland body of fresh water.

260 2217 coastal lagoon Shallow body of water close to the sea and usually with a

shallow restricted inlet from the sea.

260 2218 sea Body of salt water that usually forms a delineated part of an

ocean

260 2219 swallow hole Natural shaft, due to geological features, down which water

can flow into an aquifer or underground watercourse.

260 2220 hydrography Applied science concerned with the study and measurement

of seas, lakes and other waters where volume is more

important than the rate of flow

260 2221 hydrology Science of the occurrence and movement of water over and

below the surface of the earth from the moment of

precipitation to the moment of entry into the ocean or of

evaporation into the atmosphere

260 2222 hydrometry Measurement and analysis of the flow of water

260 2223 hydrograph Relationship, or graph, that shows the variation with time of

the level, discharge or velocity of water in a watercourse or channel

260 2224 unit hydrograph Theoretical hydrograph that would result from a storm of

unit intensity of rainfall and unit duration.

260 2225 mass diagram Graph that shows cumulative flow quantities such as the

integration of a time-flow curve

260 2226 time of concentration Time taken for a droplet of surface water that falls on the

most remote part of a catchment area to flow to a given point

under investigation

260 2227 flood detention area Area of land to impound water from river flood flow in excess

of the downstream capacity

260 2228 surface water Water that flows over, or rests on, the surface of buildings,

other structures or the ground

260 23 Groundwater

260 2301 soil water Water present in soil belt.

260 2302 soil belt Upper soil layer, constantly affected by evaporation and plant

transpiration, that is partially saturated with percolating water

260 2303 intermediate water (1) Water present in intermediate belt.

260 2304 intermediate belt Partially saturated soil layer between soil belt and capillary

Pellicular water, gravitational and capillary water suspended

in partially sealed interstices in the aeration zone.

260 2308 aeration zone Zone between ground surface and water table that comprises

the soil belt, intermediate belt and capillary fringe.

260 2309 groundwater

phreatic water

deprecated

Water within saturation zone.

260 2310 saturation zone Zone below water table and above rock flow zone throughout

which all fissures are filled with water under hydrostatic pressure

260 2311 free water Groundwater in interconnected interstices in saturation zone,

that extends down to the first impervious barrier and moves under the influence of gravity in the direction of the slope of

the water table.

260 2312 internal water Water present in rock flow zone.

260 2313 rock flow zone Zone of the earth’s crust into which water cannot permeate

and below the upper limit of which water cannot exist in a free state since all interstices have been closed by plastic flow

of the rock

260 2314 hydroscopic water Water, in soil, that is in equilibrium with atmospheric water

vapour pressure and that is essentially water in which attraction between water molecules can hold against evaporation

260 2316 water table Surface of groundwater in saturated soil or rock.

No Term Definition

260 2317 phreatic water Water in the zone below the water table.

260 2318 phreatic surface Surface to which groundwater would rise in an open ended

pipe

260 2319 phreatic zone Zone below the phreatic surface.

260 2320 recharge Flow of water to groundwater storage from precipitation,

infiltration from surface streams and other sources.

260 2321 aquifer Water-bearing formation of permeable rock, sand or gravel

capable of yielding significant quantities of water

260 2322 underflow Groundwater movement in an aquifer.

260 2323 specific yield Ratio of the volume of water yielded by unit volume of

permeable rock or soil when drained by gravity under specified conditions after being saturated to unit volume

260 2324 specific retention Ratio of the volume of water retained against gravity by unit

volume of rock or soil that has been saturated and allowed to drain completely to a remote body of mobile water by way of continuous capillary interstices to unit volume

260 2325 specific storage Ratio of the volume of water that unit volume of a vertical

column of an aquifer releases from storage as the head within

the column declines unit distance to unit volume

260 2326 storage coefficient Ratio of the volume of water that a vertical column of an

aquifer of unit cross-sectional area releases from storage as

the head within the column declines unit distance to unit volume

260 24 Miscellaneous

260 2401 water cycle Complete natural cycle of water circulation from the

atmosphere to the earth and return to the atmosphere

through various stages or processes such as precipitation,

run-off and evaporation.

260 2402 shallow well Well less than 15 m deep.

260 2403 deep well Well equal to or more than 15 m deep.

260 2404 borehole Hole, usually vertical, bored to determine ground conditions,

for extraction of water or measurement of groundwater level.

260 2405 culvert Covered channel or large pipe that forms a watercourse below

ground level, usually under a road or railway

260 2406 box culvert Culvert of rectangular cross section.

260 2407 safe yield Maximum rate at which water may be extracted from an

aquifer over a period without depleting the supply or causing

a deterioration in quality

260 2408 rain gauge Instrument that collects and measures precipitation falling

on it

260 2409 flood routing Determining at successive points along a river the timing and

form of the hydrograph of a flood.

260 2410 infiltration Passage of water through the soil surface into the soil or from

the ground into a conduit

260 2411 transmissivity Rate of flow of groundwater through a vertical strip of unit

width of an aquifer, the strip extending the full saturated

depth under unit hydraulic gradient at a fixed temperature

260 2412 leaching Removal of soluble constituents from soil or other material by

percolating liquid

No Term Definition

260 2413 return period Average interval of time between a number of events that

equal or exceed a particular magnitude, calculated from the probability of recurrence of such events

260 3 Watercourses

260 31 General

260 3101 river Water flow along a large watercourse.

260 3102 stream

beck, bourne, brook,

burn, gill, rhine, rife, rill,

260 3104 creek Small inlet on coast or estuary.

260 3105 feeder Stream or conduit that supplies water to a canal, reservoir or

pond.

260 3106 pen Stretch of water between successive weirs or locks in a river.

260 3107 leat Artificial channel that takes water from a natural

watercourse and conveys it at a shallower gradient than the watercourse for supply or power purposes.

260 3108 cut Excavated channel that forms part of a river or navigation (2)

system

260 3109 tidal length of river

tidal river

deprecated

Part of a river within the influence of tides.

260 32 Topography and regime

260 3201 headwater (1) Source or upper reach of a stream or river.

260 3202 regime (1) Dynamic equilibrium between accretion and erosion in an

open channel system or a coastal environment where the

balance existing between the two may vary over a time span from days to tens or even hundreds of years

260 3203 regime (2) State in which a river or canal has adjusted its slope and

cross section to an equilibrium condition

260 3204 reach Stretch of water between two features alongside or across a

river or stream.

260 3205 left bank Left side of a watercourse looking downstream.

260 3206 right bank Right side of a watercourse looking downstream.

260 3207 low flow channel

dry weather channel

deprecated

That part of a multistage channel that is designed to carry

base flow.

260 3208 two stage channel Channel in which normal flow is contained in the lower part

of a wider main channel.

260 3209 flood channel (1) Channel that carries excess water during flood conditions.

260 3210 flood channel (2) Channel made in an estuary by the rising tide.

260 3211 ebb channel Channel made in an estuary by the falling tide.

260 3212 navigation channel Channel for navigation (2).

No Term Definition

260 3213 flood plain Area of land that borders a river and is partly or wholly

covered with water during floods

260 3214 washland Low land adjacent to a river or drain used for storage of flood

260 3216 meander Deviation of a river from a straight course caused by erosion

of outside bends by impinging currents and accretion on

Navigation (1) with no current or a very slight current, made

possible in a river by maintaining the water level with weirs.

260 3303 riparian owner Owner of part of the bed or bank of a river.

260 3304 riparian right Legal right of a riparian owner concerning the river.

260 3305 main river Length of river so designated by statute.

260 3306 enmaining Process of adopting a new length of river as main river.

260 34 Miscellaneous

260 3401 flow duration curve Graph that shows the frequency with which the discharge in

a watercourse is equalled or exceeded during a given period.

260 3402 rating curve Graph that shows the relationship between depth and

discharge in a channel or over a weir.

260 3403 training works Structure designed to influence the location, flow, scouring or

silting capacity of a river.

260 3404 cutwater Streamlined end of a bridge pier shaped to deflect water

flowing past the bridge pier with minimum turbulence

260 3405 retention board Board used as a weir in a small watercourse.

260 3406 tidal sluice Structure to prevent tidal flow from occurring in an upstream

direction whilst allowing flow to occur in the downstream

direction at low water.

260 3407 tidal door Hinged gate in a tidal sluice operated by the flow of water.

260 3408 pointing door One of a pair of mitre gates in a tidal sluice operated by the

flow of water

260 3409 penning Action of forming a pen.

260 3410 brushing Cutting and removal of weed and bush growth in a

watercourse.

260 3411 barge bed Place where barges can moor and rest on a soft bed at low

water levels near the bank of a river.

260 3412 camp shedding Protection on the bed of tidal water to enable a vessel to rest

safely at low water levels.

260 3413 headwater (2) Water upstream of a structure

260 4 Canals and locks

260 41 Canals

260 4101 canalization Division of a river into reaches by the introduction of control

structures such as weirs to enable it to function as a canal.

260 4102 pound Stretch of water between two successive locks on a canal.

260 4103 summit canal Pound at a summit on a canal that requires an artificial

water supply to it

260 4104 offside Bank of canal without a towpath.

260 4105 winding hole Short section of canal widened to allow barges to be turned.

260 4106 canal lining Impervious lining to a canal to reduce leakage.

260 4202 double lock Arrangement of two parallel adjacent lock chambers in a

canal, sometimes interconnected to reduce lockage.

260 4301 lock gate Gate to separate water in a lock from that outside it or to

divide the lock chamber into two compartments.

260 4302 head gate Upstream gate of a lock or conduit.

260 4303 tail gate Downstream gate of a lock or conduit.

260 4304 sector gate One of a pair of lock gates that consists in plan of a quadrant

of a circle that rotates about its centre, and that can withstand water pressure from either side

260 4305 mitre gate One of a pair of lock gates that, when closed, meet at an

obtuse angle so that the upstream water pressure assists in sealing the gate contact faces

260 4306 lift gate Lock gate that opens by rising vertically.

260 4307 lock paddle

wicket

deprecated

Sluice gate to enable a lock to be filled or emptied.

260 4308 gate paddle Lock paddle installed in a lock gate.

260 4309 heel post Vertical member of lock gate, nearest to the lock wall, that

fits into a hollow quoin.

260 4310 mitre post Vertical member of a mitre gate furthest from the lock wall.

260 4311 spear post Post attached near the mitre post of a large lock gate with a

wheel at the bottom running on a curved track on the gate

platform.

260 4312 balance beam

balance bar

deprecated

Horizontal member that extends from the top edge of a lock

gate used to lever open the gate when water levels are

balanced

260 4313 anchor and collar Top hinge for lock gate that comprises a plate, with a hole to

accommodate the pintle, that is anchored into the lock side.

260 4314 collar strap and anchor Top hinge for lock gate that comprises a strap, around the

heel post, that is anchored into the lock side.

No Term Definition

260 4315 gate platform Floor of gate chamber.

260 4316 lock sill

clap sill

deprecated

Raised part of the floor of a lock against which the lock gates

bear when shut

260 4317 mitre sill Lock sill for a mitre gate.

260 4318 gate recess Recess provided in a side wall of a gate chamber to receive a

lock gate when it is open.

Pit, at the side of a lock, that contains a gate cylinder.

260 4321 capstan pit Pit, at the side of a lock, that contains a capstan operating an

underwater chain to open or close a lock gate.

NOTE Two capstan pits are required per lock gate.

260 4322 chain culvert Underwater passage that connects a lock and capstan pit and

contains a chain to open or close a lock gate.

260 4323 hollow quoin Vertical groove in corner of a gate recess within which the

Guide for lock paddle.

260 4326 ground paddle Lock paddle installed in a culvert that bypasses the lock

gates.

260 4327 pintle Vertical pin mounting for a lock gate.

260 4328 pintle pot Recessed bearing to receive a pintle.

260 44 Other lock features

260 4401 lock chamber

lock bay, coffer

deprecated

Space enclosed between the gate chambers of a lock.

260 4402 gate chamber Part of a lock within which a lock gate or pair of lock gates

260 4405 lift (1) Vertical distance that a vessel is raised or lowered when

passing through a lock.

260 4406 lockage Volume of water transferred from the upper to the lower level

of a canal or river when lowering the water in a lock.

260 45 Miscellaneous

260 4501 side pond Storage pond, at an appropriate level, connected to a lock

chamber to reduce lockage.

260 4502 cope Top edge of a dock wall or similar structure.

260 4503 step Place a lock gate in position on its pintle.

260 4504 racking Process of sealing joints between stop logs by introducing fine

suspended material into the water immediately upstream

260 4505 lock ladder Ladder in lock chamber for the use of boat crews.

260 4506 mooring ring Ring on a bank or on lock side to which craft are moored.

260 4507 roving bridge Bridge over canal to enable a horse to change from one side of

the canal to the other without being released from the tow

rope

260 4508 flexible dam Dam that consists of a flexible membrane, supported by

frames at close centres, held down to the bed by water

pressure

260 4509 clough Sluice gate formed of planks

260 4510 sanitary station Facility into which canal boat chemical toilets are emptied.

260 4511 blockage factor Proportion of water cross section of a navigational canal

obstructed by the hull of a vessel in motion

260 4512 squat Phenomenon whereby a moving vessel rises at the bow and

goes down at the stern

260 4513 aqueduct (2) Bridge that carries a conduit

260 5 Irrigation and land drainage

260 51 Types of irrigation and systems

260 5101 continuous flow

irrigation Method of delivery of irrigation water by which each irrigator receives his allotted quantity of water at a continuous rate

260 5102 supplemental irrigation Irrigation practice whereby water is supplied for

comparatively short and usually irregular periods of drought during the crop growing season so as to overcome the

shortage of soil moisture

260 5103 pumped irrigation Irrigation in which water is delivered by pumping through

260 5106 surface irrigation Irrigation in which water is directed across the land surface.

260 5107 flood irrigation Irrigation in which water is made to cover the surface of the

land to such a depth as to cause saturation for a considerable time

260 5108 border irrigation Flood irrigation in which land is divided into strips and water

is delivered into each strip from an irrigation canal.

260 5109 check irrigation Flood irrigation in which fields are divided into rectangles by

low bunds

260 5110 basin irrigation Surface irrigation of orchards by which each area or group of

trees is surrounded by a bund

260 5111 spate irrigation Surface irrigation for which earth diversion embankments

are built across normally dry watercourses to divert spate water into canals leading to bunded fields where the water is

ponded until absorbed

260 5112 furrow irrigation Surface irrigation in which water is run in furrows between

crops

260 5113 sprinkler irrigation Irrigation in which water is conducted in pipes to sprinklers

that distribute water like rain.

No Term Definition

260 5114 sub-irrigation Irrigation in which water is applied below the ground

surface

260 52 Factors and requirements

260 5201 gross irrigable area Gross area to be irrigated less such areas as are excluded

from a project by reason of their being unsuitable for

irrigation, either on account of the nature of the soil, or

because the ground is too high to be irrigated by gravity flow

or economically by pumps or other water lifting devices

260 5203 command Height of water level in an irrigation canal at an outlet or

turnout site above the general level of the land in the area to

be irrigated from that outlet

260 5204 field command Difference in water level, in an irrigation canal, and the level

of the highest point of parcel of land irrigated

260 5205 farm losses Losses of water on a farm due to uneven distribution, poor

handling, and percolation into the subsoil due to excessive

irrigation.

260 5206 irrigation efficiency Ratio of irrigation water consumed by crops of an irrigated

farm, field or project to water diverted from the source of supply

260 5207 water requirement Quantity of water from all sources required for crop

production

260 5208 irrigation requirement Quantity of water, exclusive of precipitation, required for crop

production using irrigation.

260 5209 consumptive use Quantity of water that arises from evapo-transpiration from

irrigated areas

260 5210 evapo-transpiration Evaporation of water from soils and transpiration of water

from plants

260 53 Channel delivery

260 5301 irrigation canal Canal used for irrigation.

260 5302 main canal Irrigation canal that takes water from a headworks and

delivers it to subsidiary irrigation canals.

260 5303 primary canal

lateral canal, branch canal

deprecated

Irrigation canal that takes water from a main canal to feed

lesser irrigation canals.

260 5304 secondary canal Irrigation canal that takes water from a primary canal for

No Term Definition

260 54 Piped delivery

260 5401 main line Pipe in sprinkler irrigation that conveys water under

pressure from a source of supply to feed subsidiary pipes or

sprinkler laterals.

260 5402 lateral Subsidiary conduit that branches off a larger conduit

260 5403 sprinkler lateral Pipe that feeds sprinklers

260 55 Land drainage

260 5501 land drainage System of conduits, structures and embankments required to

control water levels and to protect urban and agricultural

land from flooding, either by fresh or salt water, or to alleviate such flooding.

260 5502 land reclamation Exclusion of the sea, or other mass of water, from areas that

were previously submerged, or subject to inundation, often by the raising of land levels

260 5504 drainage system System of drains and ancillary works that conveys their

contents to a cesspool, sewerage system, outfall or other place

Drain used in agriculture to lower the water table.

260 5507 drain tile Small diameter short earthenware pipe with plain ends

260 5508 tile drain Length of drain tiles laid with open joints to form a land

Drain formed by excavating a trench and backfilling it with

granular material within which may be laid a porous or perforated pipe

260 5510 mole drain Small circular lined or unlined land drain formed in cohesive

soil by a mole plough.

260 5511 mole plough Vertical knife blade with a horizontal bullet shape at its

lower end, that is pulled through the ground to form a

continuous hole for cables, pipes or drainage.

260 5512 box drain Small square or rectangular drain.

260 5513 delph ditch Ditch, landward of sea defence works, in which overtopping or

seepage of sea water is collected.

260 5514 soak ditch Ditch at toe of an embankment or raised river bank to collect

seepage water and lower the water table in the embankment.

260 5515 counter drain Drain constructed along the toe of a dam or embankment to

collect and remove seepage and so stabilize the embankment

No Term Definition

260 5517 wet fence Water-filled ditch used primarily to confine animals.

260 5518 catchwater (1) Small channel cut into the ground on the uphill side of an

excavation to lead run-off clear of it.

260 5519 catchwater (2) Conduit to intercept water from an adjacent catchment area

and divert it into an impounding reservoir

260 5520 arterial drain Large watercourse, usually artificial, in a drainage system,

that takes water from subsidiary watercourses.

260 5521 level Land drainage district, drainage area or lowland area in

river valley or fen capable of being managed as one unit.

260 5522 fen Low land that is below high water level or needs special

drainage and is seasonally subject to controlled water levels.

260 5523 marsh Low-lying flat land, formed by natural accretion, that is

either wet and soft or needs land drainage for agricultural

use

260 5524 wastage Lowering of land surface level that results from the draining

of peat soils

260 5525 inning Land reclaimed from sea or marsh.

260 5526 tide locked Situation where the outflow from a pipe or channel is

prevented by the level of the tide.

260 5527 lift (2) Height through which liquid is raised

260 56 Miscellaneous

260 5601 rill way Channel in foreshore that carries flow from an outfall.

260 5602 cascade Series of vertical steps in the invert of a drain, sewer or

channel to prevent excessive velocity.

260 5603 open channel flow Water flow, with a free surface, through a conduit

260 5604 wetted perimeter Length of contact at a cross section between a conduit and the

liquid flowing in it

260 6 Docks and harbours

Dock with gates from which water may be pumped out

leaving it dry to enable a vessel to be built or repaired

260 6103 tidal dock Dock without gates.

260 6104 docking block One of a number of blocks to support the underside of the hull

of a ship in a dry dock.

260 6105 altar Step in wall of dry dock, used for holding the feet of the

shores that steady a vessel when the dry dock is empty.

260 6106 ship caisson Sinkable floating box that is used to close the entrance to a

lock, dry dock or wet dock by sinking in position with water

ballast

260 6107 sliding caisson Partially buoyant ship caisson, moved on rollers from a

housing chamber

No Term Definition

260 6108 limpet dam

limpet, leech

deprecated

Transportable open-topped working chamber with one side

open, shaped to fit a dock wall, that seals against the wall as

water is pumped from the enclosed space to provide a dry working area

260 6109 dockyard Naval establishment with docks, building slipways, stores

and associated facilities

260 6110 port Group of berths or docks, or the town or city in which they are

situated

260 62 Berths

260 6201 quay Platform structure, usually backing onto land, provided

alongside a berth.

260 6202 wharf Riverside quay for commercial use.

260 6203 pier Structure, usually open, that projects from the shore and is

used as a promenade or to provide berths.

260 6204 jetty Structure that provides access to one or more berths at some

distance from the shore.

260 6205 jetty head Platform structure at the offshore end of a jetty.

260 6206 lead-in jetty Framed structure that guides vessels into the entrance of a

confined area such as a lock or dock.

260 6207 staithe Elevated waterside structure for loading vessels

260 6208 island berth Berth at which a vessel is moored to an isolated structure

that is not structurally connected to the shore.

260 6209 berthing line Line of face of undeflected fender at a defined water level on a

quay or, where no fenders exist, the quay wall face.

260 6210 basin Area of open water, such as that on a canal or in a harbour,

that provides berths.

260 6211 impounded basin Basin connected to tidal water by a lock and in which the

water level is approximately constant

260 6212 tidal basin Basin directly connected to tidal water.

260 6213 yacht basin Area of water within a harbour that is allocated specifically

for berthing of yachts

260 6214 marina Basin with berthing facilities and ancillary services for

pleasure craft

260 63 Fenders

260 6301 fender Energy absorbing device on the side of a vessel or shore

structure for protection from damage due to impact

260 6302 elastomeric fender unit Unit formed of elastomeric material that absorbs the energy

of impact of a ship during berthing by being deformed elastically by compression, bending or shear or a combination

of such effects

260 6303 pneumatic fender unit Elastomeric container filled with air under pressure that

absorbs the energy of impact of a ship during berthing

260 6304 hydraulic fender Fender in which the energy of impact during berthing is

absorbed by a hydraulic device

260 6305 non-recoiling fender Hydraulic fender with a series of horizontally mounted

hydraulic jacks that exert a force against the hull of a ship

through a fender face, counteracted by the mooring lines.

No Term Definition

260 6306 floating fender Fender that consists of floating baulks, cylindrical bundles of

timber or elastomeric cylinders

260 6307 hanging fender Fender that comprises a timber frame suspended from a

marine structure

260 6308 gravity fender Fender that absorbs the energy of impact during berthing by

raising a suspended weight

260 6309 rotating fender Fender that comprises one or more pneumatic tyres or

elastomeric cylinders that rotate on a vertical axis to

facilitate movement of a ship along a quay or into a dock.

260 6310 collapsible steel fender Fender that consists of a corrugated steel tube that absorbs

excessive energy of impact during berthing by plastic deformation

260 6311 spring fender Fender in which steel springs are used, usually to provide the

top support for fender piles acting as propped cantilevers.

260 6312 brushwood fender Floating fender composed of bundles of brushwood.

260 6313 buoyant fender Fender, anchored to the sea bed, that floats in front of a quay

face and that is forced backwards and downwards during berthing

260 6314 fender pile Cantilever pile installed in front of a marine structure to act

as a fender.

260 6315 rubbing strip Replaceable hardwearing abrasion-resistant facing strip on

the side of a vessel or quay.

260 6404 composite breakwater Breakwater that consists of a submerged rubble mound

surmounted by a vertically faced structure projecting above

sea level.

260 6405 main breakwater Breakwater that forms the side of a harbour from which the

prevailing wind blows

260 6406 lee breakwater Breakwater that forms the side of a harbour remote from the

prevailing wind

260 6407 island breakwater

mole

deprecated

Breakwater not connected to the shore.

260 6408 roundhead Rounded enlargement at the end of a breakwater or rounded

end to a dock entrance wall to reduce adverse effects of flow

past it

260 65 Miscellaneous

260 6501 dolphin Isolated structure or strong point used either to manoeuvre a

vessel or to facilitate holding it in position in a berth.