The following guide is here to assist you with some of the common terms shared amongst the many stakeholders working in the watershed.
Culverts
Apron: a smooth (generally concrete) surface that is placed between culvert and channel to improve capacity and reduce erosion.
Backwater: to place a culvert or use a weir such that there will always be some depth of water within the culvert.
Bedding: fine gravel or crushed rock placed around culverts to evenly distribute load.
Bottomless: a culvert consisting of an arch with an open bottom such that native streambed is exposed.
Box Culvert: culvert of rectangular cross section, commonly of precast concrete.
CMP: corrugated metal pipe, generally galvanised and/or tarred for corrosion resistance
Cut-off Wall: a collar (metal, concrete etc) placed around a culvert to prevent piping.
Depth of Cover: depth of fill placed atop a culvert.
Directional Drilling: drilling sideways under structures/roadways/streams etc to place pipes, utility lines without excavation. Generally limited to less than 30cm diameter.
Flap Gate: a passive "trap door" device placed on culvert outlets to prevent inflow. The hinge can be on the top or side of the culvert.
Inlet Limited: a condition in which the maximum flow capacity of a culvert is determined by the hydraulic conditions of the inlet. Small changes to the inside of the culvert or outlet structure will have no effect on maximum capacity.
Inlet Structure: An arrangement of wing walls and apron that smoothes the hydraulic transition from open channel to culvert flow and increases maximum capacity. It may also be the mounting point tor a trash rack.
Invert: the bottom of the culvert.
Headwall: a wall built at top and sides of a culvert end to secure adjacent soil.
Multi-plate: a large culvert made up of segments bolted together on site.
Obvert: interior top of a culvert, equal to the invert plus the culvert diameter
Outlet Structure: An arrangement of apron, wing walls and sometimes energy absorption structure at the end of a culvert.
Pipe Jacking: a process by which a culvert is pushed horizontally through the ground to allow placement of a culvert without excavation.
Pipe Arch: a "squished" CMP culvert that has greater invert width.
Piping: water flowing along the outside of a culvert. This can lead to erosion and failure.
Roughness: a of quantifying the degree of drag on flowing water by a surface. Most commonly expressed as a dimensionless Manning's number.
Slope: measurement of the change in elevation with distance.
Sluice Gate: a manually or automatically operated sliding or rotating panel to restrict flow into or out of a culvert.
Surcharge: a condition in which the water elevation at the upstream end of a culvert exceeds the culvert obvert.
Trash Rack: a metal gate placed at the upstream end of a culvert to prevent woody debris, rocks etc from entering the culvert
Wing Wall: a flaring vertical wall on either side of a culvert.
Open Channel Flow
Critical: the flow condition at which point the water velocity equals the wave speed.
Free Board: the vertical distance from water surface to top of channel, dike etc.
Hydraulic Jump: an abrupt transition from super to sub critical -also know as a standing wave. Often used to disapait energy.
Laminar: flow condition with no waves, eddies etc. Rarely encountered in open channel flow.
Roughness: a way of quantifying the degree of drag on flowing water by a surface. Most commonly expressed as a dimensionless Manning's number.
Slope: measurement of the change in elevation with distance.
Turbulent: flow condition with waves, eddies etc.
Velocity Profile: variation in water velocity vertically and horizontally due to roughness effects.
Weir: structure that spans a channel and controls the local streambed elevation.
Aggregates
Alluvial: native aggregates deposited by water flow.
Boulder: pieces of rock larger than 200mm.
Clay: grains of rock less than 0.001mm.
Clear Crush: crushed and screened rock that contains no fines -very porous.
Cobble: pieces of rock between 60mm and 200mm.
D-X: size that X% of an aggregate sample is smaller than.
Filter Layer: cobble, gravel, etc., placed under riprap to prevent native fines from washing out through the riprap. Geotextile may be used to supplement or replace this layer.
Geo-textile: heavy weight fabric of generally synthetic material used to stabilize aggregates, soil etc. May be of woven or felted composition.
Glacial: aggregates deposited by or through glacial processes.
Gravel: crushed or alluvial rock of size between 2mm and 60mm.
Hog Fuel: crushed, shattered or shredded bark, wood etc.
Loc-Bloc: large precast concrete brick (2.5'x2.5'x5') placed to interlock with others.
Mulch: raw or composted wood chips, leaves etc.
Overburden: native soils overlying aggregate to he mined or subsoils to be constructed upon.
Overs: oversized rocks, boulders etc.
Pit Run: unscreened alluvial aggregates as extracted from a pit.
Porosity: the percentage of open spaces between pieces of gravel cobble etc.
Procter Test: a method to determine the maximum density that can be achieved through wetting and packing for a given aggregate.
Rip Rap: coarse angular rock, generally blasted or crushed. Also known as shot rock.
Road Base: a mixture of gravel, sand and fines that compacts well.
Sand: grains of rock between 0.06mm and 2mm.
Silt: grains of rock between 0.002mm and 0.06mm.
Topsoil: native or manufactured soil with 15-40% organic content.
Well Graded: coarse grained soil with an even distribution of sizes.
Vegetation
Ball & Burlap: packaging method for field grown trees - root balls are wrapped in burlap and bound with string, wire etc.
Calliper: diameter of nursery tree at the butt.
C/C: center to center ~ distance between plants.
Coir: coarse fiber derived from outer husks of coconuts.
Conifer: a tree or shrub (usually evergreen) with seed cones and resinous sap.
DBH: diameter breast high ~ tree trunk diameter at 4-5' off the ground.
Deciduous: tree or shrub that loses its foliage during the winter.
Dibble: rod-like tool used to plant live stakes, plugs etc.
Hydroseed: to spray a mixture of seed (generally grass), fibre and tackifyer (glue) for rapid planting and erosion control.
Fascine: a bundle of live branches (generally willow or cottonwood) placed perpendicular to a slope to form a stable edge.
Hay: cut and dried grass and legumes ~ often with seeds.
Invasive: plants that grow so aggressively that they will dominate an area -generally of imported origin.
Legume: a plant that hosts nitrogen fixing bacteria within its roots such as peas.
Live drain: a bundle of live branches buried within a slope to convey water down the slope and limit erosion.
Live whip/stake/pole: dormant branches of a self-rooting woody species used to establish vegetation, stabilize slopes etc.
Pot Size: standard nursery stock sizes expressed in inches diameter or gallons volume.
Plug: small (2-6") plant grown in a multi-celled tray.
Shock: dehydration of plants and trees due to transplanting.
Shrub: small to medium plant of woody character generally with multiple stems.
Snag: standing dead tree.
Soil wrap: geotextile used to enclose topsoil as a means of slope stabilization.
Straw: coarse stalks (generally of grain) without seeds.
Tree: medium to large plant of woody character, generally with a single stem.
Wattle: low retaining wall of live whips/stakes placed on a slope to form a terrace and limit erosion.
Wildlife tree: tree that is topped/killed but much of the trunk left standing (man-made snag).
Wind throw: tree blowdown, often due to removal of adjacent trees.
River Hydrology
Aggrade: to increase channel elevation by sediment accumulation.
Bedload: coarse aggregates carried by flowing water (rolled or bounced, but not suspended).
Confluence: the meeting of two streams.
Debris torrent: a mixture of water, soil, vegetation etc that flows with great speed and force down a channel.
Degrade: to decrease channel elevation by sediment removal (erosion or extraction).
Floodplain: the region flanking a river channel that is subject to periodic innundation.
Headward erosion: localized channel degradation that progresses upstream. Often due to removal of bedload.
Incise: downcutting of a channel, generally without a corresponding downcutting of the floodplain.
Meander: the tendency of a channel to move laterally.
Overland flow: river flow outside of defined channel.
Point bar: accumulation of bedload on the inside of a curve.
Pool: a localized increase in water depth, generally formed by scour processes.
Sinuosity: ratio of total strean1 length to straight line distance.
Riffle: reach of river channel characterized by shallow medium velocity flow over cobble or small boulder.
Run: reach of river characterized by deep medium to high velocity flow.
Scour: localized erosion of substrate and banks by river flow.
Sediment budget: annual volume of sediment transported by a river.
Tail out: riffle at downstream end of pool.
Tributary: smaller stream that contributes to flow of larger stream.
Undercut: a portion of stream channel underneath an overhanging bank, log, rock etc.
Pumps
Archimedes screw: type of pump that looks like an angled corkscrew.
Axial flow: type of pump that acts like an outboard motor in a casing.
Centrifugal: type of pump that "flings" water outwards and into an exit pipe.
Dynamic head: the total equivalent head drop due to the static head and all friction losses.
Discharge: volume of water pumped at a specific head.
Float switch: float that can be set to turn pump on or off at set water level.
Impeller: the rotational element that actually contacts and moves the water.
Forebay: the structure for a pump, often holds the trash rack.
Static head: vertical distance from inlet water elevation to discharge elevation.
Sump: deep water filled hole that the pump inlet is placed into. Constructed to increase water depth in order to reduce vortex formation and air entrainment.
Fish Passage
Denil: fishway that rectangular in cross section and has many backward facing vanes that cause water to flow black on itself and induce extreme turbulence.
Jump height: vertical distance between water surfaces of two pools.
Jump pool: the "take-off' pool at the base of a fall. Generally must be a minimum of 1.25x as deep as the jump height for leaping salmonids.
Off set baffles: beams, logs, curbs etc placed on either side of a culvert, flume etc so as to create turbulent flow and ease fish passage.
Orifice: a fishway consisting of stepped pools connected by submerged holes.
Pool and weir: a fishway consisting of stepped pools connected by small falls.
Steep-pass: simplified design of Denil fishway.
Slot: a fishway consisting of stepped pools connected by vertical slots.
Surveying/mapping
At grade: at the local ground elevation.
Bench mark: an elevation reference point.
Chainage: linear distance.
Contour: an imaginary line linking points of equal elevation.
Flag: a piece of survey ribbon.
Geodetic: an elevation correlated to international standard.
GPS: Global Positioning System ... a series of satellites and ground based hardware that allow precision location anywhere on the surface of the globe.
I/P: abbreviation -iron pin (normally used to mark comers of property lots).
Level: horizontal, or: an optical/mechanical device that allows determination of horizontal.
O/S: abbreviation -offset (generally used when a survey stake cannot be placed on the exact point of interest).
Rod: measurement stick used with a level or theodolite.
R/W: abbreviation - right of way.
Stake: wood stake used to mark point of interest.
Theodolite: survey instrument with vertical and horizontal degree gradations.
Traverse: survey circuit.
UTM: Universal Transverse Mercator - standard map projection.
Concrete
Aggregate: sand, gravel etc mixed with cement to form concrete.
Batch plant: local facility for preparation and distribution of concrete.
Blow out: rupture of concrete forms.
Cast-in-place: construction of forms and filling with concrete at final location.
Cement: aka Portland Cement - a dry powder consisting of burned limestone, gypsum and other chemicals - used the concrete, mortar, grout etc.
Concrete: a mixture of Portland cement, aggregate and water to form a stiff slurry that will chemically react and harden.
Exposed Aggregate: decorative technique for driveways, walks etc that involves washing half set concrete so as to expose gravel aggregate.
Form: wood or metal structure that concrete is poured into.
Grout: a concrete mixture that is made with fine aggregate to achieve a smooth surface or easily pumped mixture.
Light weight: the addition of lightweight aggregates such as pumice.
Precast: concrete products cast at a site remote from the final installation.
Pump: to use a pump to transport wet concrete from truck to fonn; or in the case of grout, to fill voids by pressure.
Re-bar: ribbed steel bars of various sizes used to give concrete strength in tension.
Slump: the "sloppiness" of wet concrete, generally more slump equals less strength.
Strength: the resistance of a cured core of concrete to crushing ~ expressed in Mpa.
Tilt-up: a method of building construction whereby concrete walls are cast in horizontal forms on site and then tilted to the final vertical position.
Vibrate: to use a mechanical device to vibrate wet concrete within forms to cause it to flow more easily and flow around re-bar etc.
Activities
Bar scalping/skimming: to remove a thin layer (1-5') from the top of gravel bars.
Drainage maintenance: to remove sediments and vegetation from ditches/ canals etc in order to improve conveyance.
Dry /wet pit mining: to isolate gravel extraction to a confined hole in a bar. Wet/dry refers to whether it goes below the water table at the time of extraction.
Equipment
Articulated rock truck: a four-wheel drive dump truck with heavy duty tapered box and pivoting connection between cab and box.
Backhoe: a rubber tired vehicle with loader bucket in front and small excavator bucket at back.
Blast mat: a large heavy mat made from rubber tires used to confine debris during rock blasting.
Bob-cat: trade name for a four wheeled skid steer loader.
Breaker: hydraulic jackhammer, often mounted on an excavator.
Bull dozer: with front mounted blade.
Excavator: generally tracked vehicle with rotating body and front mounted digging ann.
Low bed: Truck tractor and low semi-trailer used to transport large excavators, dozers etc.
Grader: rubber tired vehicle with blade mounted between front and rear axles.
Hiab: Flatbed truck with hydraulic crane for loading and unloading freight.
Loader: or tracked with wide front mounted bucket to serape and load.
Reach: distance that an excavator arm can extend.
Spider: specialized excavator with four legs that can negotiate steep slopes and rivers with minimal impact.
Stone slinger: conveyor belt equipped dump truck than can precision place or "throw" gravel.
Swamp pad: large wood pad used to distribute excavator weight in soft conditions.
Swing: the space required for an excavator to rotate.
Tandem: tandem axle (rear) dump truck.
Thumb: metal beam located opposite an excavator's bucket, used to grip rocks etc.
Tree spade: specialized truck mounted device used to dig and transport large trees.
