GLOSSARY:
Establishing a common vocabulary which is widely accepted by professionals is a critical importance in any professional field. Currently there is no formal glossary of terms available to practitioners of waterway rehabilitation. Therefore the author has chosen to use terms used in the widely respected “A rehabilitation manual for Australian Streams” by ID Rutherfurd et.al. where ever possible. (Information in brackets accompanying some of these terms has been added by the author in an attempt to clarify the term for lay people.)
Where useful terms do not appear in “A rehabilitation manual for Australian Streams” they are prefaced in the glossary with an asterisk. The definitions of these asterisked terms have been provided by the author.
*Access Track:
A graded track which runs beside the creek typically providing pedestrian but not vehicular access. An Access track helps facilitate both creek maintenance, such as planting and weed control, and recreational use. The typical width of a track is approximately 2m. This enables two people to walk abreast but too narrow for most vehicles.
*Angle of Repose
The angle of a creek bank that is shallow enough to discourage slumping while encouraging vegetation to become established. Typically about 45 degrees.
*Animal
A living organism with independent movement. Members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects and humans.
Bank
The relatively steep part of a Stream channel cross-section, generally considered as being above water level. (And ending at the Flood plain.)
*Bed
The flat or flattish surface that the Creek runs over
Batter
The slope of the Bank often used to describe changing the bank slope.
Biodiversity
A word used to describe biological heterogenecy. It covers the number of species of plants and animals present, as well as how different they are from one another. (All the different plants and animals occurring in a given location)
*Biodiversity Corridor
A fenced section of the landscape with minimum dimensions of 20m x100m containing continuous native vegetation.
*Biological Topography
Describes a generalised overview of the type, health, variety and quantity of living organisms in a given location. Eg “The biological topography of this patch of remnant vegetation is quite poor.”
*Canopy lock
When the canopy of the same species of plants grow so closely together so as to out shade and outcompete other species, particularly weeds
Catchment
The area of land drained by a river and its tributaries. (The area where water that drains into a given waterway collects)
Chain of Ponds
A type of natural stream morphology once common in humid Australia, but now largely destroyed. Characterised by prominent ponds separated by densely vegetated zones. (A sequence of ponds occurring at regular intervals along a waterway which are divided by Grassy Slides.)
Channelized
xxxx.
*Code of Best Practice
A commonly accepted document specifying best practice in a given field
Crash Grazing
A short burst of grazing in a protected area. (of riparian vegetation)
*Creek
A naturally occurring channelized waterway that runs intermittently. The term is commonly used to describe not only the channel but also the adjacent Verges and associated vegetation.
*Creek Architect
The individual who is designing the Creek rehabilitation plan
*Creek Rehabilitation Plan
This is the plan which is drawn up by the Creek Architect with input from the Landholder and ideally the local Landcare group
*Creek System
The sum of all interactive elements that impact on the creek. These include elements such as surrounding land uses, migratory animal species, under lying geology etc.
Degraded
A waterway that has been damaged by human impact so that it no longer has the qualities of the original asset.
Ecology
The study of organisms and how they interact with each other and their physical surroundings.
Ecosystem
The sum of everything pertaining to ecology at a location. This includes physical habitats and organisms.
Ephemeral stream
A stream which flows intermittently, ie. The flow of water regularly stops although pools may remain.
Flood
A flow in a stream that exceeds the normal channel capacity and goes over the banks onto the floodplain
Flood Plain
A flat area adjacent to a stream that is covered by floods every year or two.
(A flood plain can also relate to an area that used to get flooded but no longer does due to channel incision)
GIS
Geographical Information System, A computer program that manages spatial data in layers. (A computer program which shows geographical information)
*Grassy Slide:
An area of grassy aquatic vegetation located between ponds of water in a waterway. The Grassy Slide permits water to transition between two ponds of water at slightly different levels without causing erosion.
*Green Ford:
A Loosely compacted “ford” Paddock Rock held together by aquatic vegetation. The top of the rock is at the same height as the bed of the waterway. A Green Ford provides a predictable crossing point on a creek at times of low flow. Typically a Green Ford enables a Access Track to continue across the creek.
*Green Weir
A Loosely compacted “cascade” of paddock rock held together by aquatic vegetation. A Green Weir is used when a small Head Cut has formed and vegetation is not going to be sufficient to stop the erosion moving up stream.
The Green weir is intended to enable the water to transition the change of level in the creek bed caused by the Head Cut without causing additional erosion.
*Gully Erosion
Erosion process that are occurs in the bank of the main creek channel creating a newer and smaller channel usually at right angles or angled slightly upstream from the existing channel. Due to the short distance between the head and the toe of the Gully the gradient is markedly steeper than the main creek channel and as a result the erosion process can proceed very rapidly in high rainfall events.
*Hard Bed Creek
This type Creek has a prominently stone or gravel Bed.
*Hard Works
Hard works are works in the creek that require the use of materials such as stone, concrete, steel or timber.
Head Cut
Also called a “knickpoint”. A very steep section of stream bed that migrates upstream if not held by a bed control. (The point in a creek where the “natural” bed of a creek steps down as the result a Step Erosion process.)
Hydrology
The science that considers the distribution of water over the land as opposed to Hydraulics which considers the physical effects of the water in its passage.
*Inertia pool
An inertia pool describes a situation where enough water has collected in a pool for the mass of the water to slow the speed of water running into it.
Incised stream (Creek)
A Creek that has eroded its Bed and Banks such that it has a very low flood frequency. In other words, the channel cross sectional area is obviously too large for its catchment area.
(A Creek that has eroded so far that the current Bed is significantly below its original height.)
Indigenous vegetation
Any local indigenous plant community containing throughout its growth the complement of native species and habitats normally associated with that vegetation type or having the potential to develop these characteristics. It includes vegetation with these characteristics that has been regenerated with human assistance following disturbance, but excludes plantations and vegetation that have been established for commercial purposes. (Taken from the New Zealand Biodiversity Strategy - Glossary)
*Landcare group
For this document a Landcare group is to be taken to mean either literally a Landcare group or any other community group such a a Friends of group which is involved in helping rehabilitate the native environment
Large Woody Debris
A dead tree, or portion of a tree, that has fallen into a stream. Usually considered to be greater than 0.1m in diameter, and over a meter long. Also called snags or LWD. (Trees or large pieces of trees that have fallen or been placed in a Creek. Also called snags.)
Local Vegetation
Vegetation from the local area but which is not necessarily indigenous to a particular site.
*Morphology
The shape of something.
*New Creek
An incised channel formed by water which has occurred as the result of human activity post 1750
*Nursery Species
Typically short lived but fast growing species which are planted to give initial protection to more long lived or fragile species
Off-channel watering
Stock watering point provided away from the stream banks, e.g. Water may be pumped to troughs in a paddock.
*Original condition
The condition that the Australian landscape is assumed to have been in prior to 1750
*Paddock Rock:
Pieces of rock which vary in size between a golf ball and a soft ball.
Perennial flow
Flowing all year.
Reach
A length of stream, typically 5 to 30 km long, which is relatively homogenous with regard to the hydrology, physical form, water quality and aquatic life.
(A length of creek or waterway typically 5 to 30 km long and commonly identified by changes in ecological topography.)
Rehabilitation
The return of as much as possible of the original, pre European, characteristics of a stream, including the physical structure and stabilization of water quality, flow regime, and the suite of organisms in the stream. The organisms present in the stream are a good measure, in most cases, of the health of the stream, and thus whether it is being rehabilitated. Ideally, improvements introduced to the stream should be self sustaining. (A process aimed at halting the decline of a creek system and then returning it to a pre determined level of stability as close to Original condition as possible.)
Restoration
Replicating the original state of a stream in regard to water quality, structure and stability, flow regime, and plant and animal communities.
(A process aimed at returning a creek system to its Original condition.)
Revetment
Artificial bank protection.
Riffle
The high point in the bed of a stream between two pools. It is often covered in gravel or coarser material and experiences rapid, turbulent low flows.
(Collection of small rocks, pebbles and or gravel that occur between pools of water along a waterway.)
*River
A waterway which runs continuously and at times can be navigated by a rowing boat.
*Rock Chute
Scour
The short-term erosion of a stream bed i.e. the bed scours and then fills to about the same level, unless it is degrading or aggrading.
(Type of erosion caused by the friction of running water.)
*Sediment slug
A wave of sand or gravel that moves down a stream channel usually introduced into the stream in a pulse by mining, gullying, major floods or other extreme events.
Sheet erosion
The erosion of the surface of a paddock or other portion of the catchment as a thin layer of soil.
*Soft Bed Creek
This type of creek has a base predominantly consisting of softer alluvial materials such as soil, organic material, silt and or clay.
*Step Erosion
Refers to erosion that is moving up a creek producing clearly pronounced steps in the bed of the creek. Step erosion most often occurs in Soft Creeks. This form of erosion can be one of the fastest moving and destructive forms of erosion.
Subaierial erosion
Erosion of streams that is caused by processes unrelated to the flow of water in the stream eg erosion by cattle or rain.
Sustainable
Management decisions or rehabilitation works result in sustainable ecological communities if the community does not degrade and maintains its equilibrium with further intervention. (A point where the key components of a defined system are in a state of equal and lasting balance.)
*Swale
A moist drainage line in the landscape, often spring fed, which occasionally. Contains a small quantity of free flowing water.
Stream
Drainage features from small creeks to large rivers. Generally the drainage feature occurred in some form prior to European settlement.
(A natural waterway that runs continuously but is too small to be navigated by a rowing boat.)
Terrace
A flat surface lying above the elevation of the floodplain. Often a former floodplain. Terraces will be seldom, if ever, flooded.
Tunnel Erosion
Water moving underground becomes concentrated enough to start the erosion process underground. Often the first time that tunnel erosion becomes obvious is when the roof of the tunnel caves in leading to a the rapid creating expansion of a gully.
Turbidity
The cloudiness of water caused by reduction in the transmission of light. Often caused by suspended sediment and other material.
*Verge
20m of typically flat land that runs adjacent to both sides of the creek channel.
*Watering Hole
Place where there is typically free standing water all year around within a biodiversity corridor.
*Zone
Zone is a more general term used to describe the area taken up by one of the 3 main areas of a Creek, The Low flow channel, the High flow channel and the Verge. Eg which Zone are we planting out today?