Water quality monitoring in Australia.
Habitat assessment. http://5bio5.blogspot.com/2013/03/water-quality-monitoring-in-australia.html
Materials were taken from the site:10.3.2013.
Waterwatch Australia. This is a site of Australian Government.
A reference to this web-page is at the site:
Monitoring water quality
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Module 3 - biological parameters
Waterwatch Australia Steering Committee
Australian Government Department of the Environment and Heritage, 2004
ISBN 0 6425 4856 0
Waterwatch Australia Steering Committee
Australian Government Department of the Environment and Heritage, 2004
ISBN 0 6425 4856 0
Habitat assessment
This section describes how you can rate the health of the habitat on a scale of excellent, good, fair or poor. The rating:
· assesses the health of the site for freshwater organisms and its value for human uses
· allows you to monitor the condition of the site over time
· allows you to compare one site with another
· identifies areas that need restoring or protecting.
All the result and record sheets required to undertake a Habitat Assessment can be found at Appendix 1 of this module.
Plants growing along the edge of the waterbody are called riparian vegetation. Riparian vegetation includes native and introduced species that ideally form a broad band (the riparian zone) along the edge of a waterbody. For an estuary, the riparian zone starts from the highest high tide mark. Riparian vegetation protects the waterbody from agriculture and other human activities near the stream.
Natural riparian vegetation is a valuable source of food and shelter, for animals on the land as well as for freshwater organisms. Leaf litter, insects and fallen branches from overhanging native trees give year-round food, habitats and shelter for native fish and invertebrates and, in northern parts of Australia, for turtles (seeFigures 9.1 and 9.2 ).
Figure 9.1: The riparian environment. Source: Munks S, 1996
Figure 9.2: Comparison of a native and willow-lined bank. Source: Munks S. 1996
Riparian vegetation shades the stream and the banks, making the water in small waterways as much as 10°C cooler than the water in equivalent unshaded streams. Temperatures that are higher than expected for the season can be lethal to many freshwater plants and animals.
The roots of suitable species of riparian vegetation bind the soil of the banks, holding it together against erosion by the water. Aboveground plant parts interrupt any overland movement of water, sediment, nutrients, pesticides and herbicides into the water.
In contrast, where there is either little riparian vegetation or only introduced riparian plants, especially those that lose their leaves in winter such as willows, the waterbody may be deficient in good food supplies, or in snags and other underwater habitats; it may be contaminated by pesticides and sediment, or be subject to wide temperature variations.
Streams often have pools and riffles and runs, and this variety of habitats is able to support a variety of fauna species. A riffle is a section of a river or stream where shallow water flows over rocks in rapid turbulent flow. Riffles are important for aerating the water (adding air and therefore oxygen) and for providing a habitat for many macro-invertebrates. Large slow-flowing rivers may not have riffles but may have quiet pools, which suit fish more than macro-invertebrates. Lakes can have beaches and inlets that are shallow and stony, as well as deep areas.
When waterbodies have been affected by human activities they may be deeper, or shallower, or straighter, or less braided than unaffected waters. Although shape variations like these occur naturally between waterbodies, they can also be a result of gravel extraction, sedimentation, channel straightening and other river engineering works.
Your group’s approach to habitat surveys will depend on its goals and the resources available. Site descriptions and habitat surveys are excellent tools to use when setting priorities for your Waterwatch group. They help the group understand the relationships between the land uses on the surrounding land, and possible causes of problems in the waterbody.
A 'habitat rating' is different from a ‘site description’. Rating involves giving each habitat feature a score that represents its quality or condition. Scores are added together to form a rating for the whole site (see Habitat Rating Sheets (Awareness and River Health Assessment in this module). Once completed, ratings make it possible to compare sites from different parts of the catchment. Habitat ratings can be recorded in the Waterwatch Australia Database for community water monitoring data and information(see Module 5). Sites rated as healthy or good can be useful for reference or as sources of information about vegetation types.
The condition of the habitat influences the physical and chemical quality of the water and the kinds and numbers of macro-invertebrates that live at a site. The assessment of habitat quality at the sample sites is essential to interpreting the test results. Habitat surveys and ratings can help your group determine if poor water quality is caused by a loss of riparian vegetation and by eroding waterbody banks or by stresses elsewhere in the catchment.
· Returning to the same site and checking for the same things, say once a year, will allow you to identify longterm changes in habitat quality. Photographs taken from the same place every year would be a useful addition to your assessment of the waterway.
Rating the health of your waterbody’s habitats
To assess the health of the habitat around the stream you are monitoring, you will need to consider five features:
· quality of verge vegetation;
· quality of bank vegetation;
· extent of in-stream cover;
· degree of bank erosion and stability; and
· variety of riffles, pools and bends.
Bank vegetation refers to trees, shrubs, grasses, etc. actually growing on the bank. This vegetation provides food and shelter for aquatic animals in the form of fallen leaves, twigs and branches, etc.
Verge vegetation is considered to be stream side vegetation up to 40m from the bank of wide rivers or 10-20m from the bank of small streams. The verge vegetation can be quite extensive but many streams in urban areas have almost no verge vegetation at all. The condition and type of vegetation around a water body gives a good indication of the quality of the aquatic environment. It helps to explain physical and chemical changes and the macroinvertebrates found in the water.
In-stream cover refers to the diversity of living places available to aquatic life and includes aquatic vegetation, woody debris, snags, fallen trees, logs and rocks. Streams with a rich diversity of in-stream cover allow fish and macro-invertebrates to shelter from the current, feed and reproduce. Aquatic plants supply food and oxygen, and protruding snags form roosting and preening sites for birds.
Bank erosion and stability. Streams naturally erode, usually on the bends of meanders. However, changes in adjacent land use can cause a stream to become unstable, resulting in continuous erosion along its channel. Such changes include increased run-off from impervious surfaces and piped tributaries, stock access, or direct interference such as straightening or channelling the stream. If it has been stabilised with concrete banks, the stream will be stable but should not be ranked highly as it is not ecologically healthy.
Riffles, pools and bends. The variety of habitats found in riffles, pools and bends helps to support a variety of living things. Before you consider assessing this part of the habitat, make sure that riffles, pools and bends are a natural part of the catchment being studied. For example, large slow flowing rivers may not have riffles but the bends provide different habitats because the cutting action of water at bends provides deeper areas.
How to carry out the survey
1. Survey both sides of the stream for approximately 100m and extending out from the water by 40mfor a medium/ large size waterway or 10-20m for a small stream.
2. For each feature in Table 7 Habitat Descriptions and Ratings, select a category (excellent, good, fair or poor) that is most like your habitat. If the description in the table does not match, try another category.
3. Record the score for each feature on the Stream Habitat Rating Sheet.
4. For an overall assessment of the site, add up the scores to obtain a total. Refer to Tables 7 and 8 for an interpretation of your assessment. Bank and verge vegetation and instream cover are more important in determining the health of the habitat than either bank erosion and stability or riffles, pools and bends.
Quality control
The main quality contol challenge for the Habitat Rating is to ensure consistent evaluation of features of the habitat. The easiest way to accomplish this is to have one team whose job is to carry out the habitat assessment throughout the catchment. From time to time the evaluation of habitats by field teams should be compared with that of your Waterwatch coordinator.
While this allows valid comparisons to be made within your catchment or region, it does not guarantee valid comparisons across regions or the state because of subtle differences in human perception.
Features of the habitat | Excellent | Good | Fair | Poor |
Riparian habitat | 8 | 6 | 4 | 2 |
(Examine habitat over a length of 100 m and 40 m back from the water of a medium size waterway or less for a small stream) | Mainly undisturbed native plants on both sides of waterbody to 40 m from water. Introduced species are present at very low levels or completely absent. | Native vegetation on both sides of waterbody in generally good condition. Some intrusion of introduced species. Riparian zone less than 40 m but still wide. | Mixture of native and exotic species on both banks, OR one side may be cleared and the other side undisturbed native plants OR narrow corridor of native plants on both sides. Other impacts may be present e.g. fire, stock grazing in riparian zone | Any native vegetation present is severely modified on both sides by grazing or human access, OR cleared land both sides (e.g. agriculture, housing) OR species present are virtually all exotics (willow, pines, introduced grass etc). |
In-stream cover | 8 | 6 | 4 | 2 |
(aquatic plants, snags, logs, bank overhangs and overhanging vegetation) | High cover on banks. Abundant in-stream, and overhanging vegetation. Abundant snags and logs or boulders. Bank overhangs present. | Good cover on the banks, moderate areas of instream and overhanging vegetation. Some snags, logs or boulders. | Some cover. Some areas of in-stream or overhanging vegetation. Invasion of bank vegetation by terrestrial grasses. Few snags, logs or boulders. | Little or no cover. No overhanging vegetation or in-stream plants. The stream is largely cleared with few or no snags or logs. Any boulders present are submerged. Site may have rock or concrete lining. |
Bank erosion & stability | 4 | 3 | 2 | 1 |
(roots, bare soil, slumping, erosion, fall-ins, cracking of bank) | Stable. No erosion or deposition evident. No slumping of banks. Lower banks completely covered with root mat, grasses, reeds or shrubs. | Very occasional and very localised erosion. Little slumping or undercutting of bank. No significant damage to bank. Good vegetation cover. | Some erosion evident but localised. No continuous damage to bank structure. Moderate vegetation cover. | Extensive areas of erosion. Unstable, extensive areas of bare ground, bank failure such as cracks and fallins. Little vegetation cover. Despite stability of concrete channels they score only 1. Areas of bank works score 1 because of instability. |
Riffles, pools & bends | 4 | 3 | 2 | 1 |
(Before you consider assessing this part of the habitat, make sure that riffles, pools and bends are a natural part of the catchment being studied. If not, then ignore this part) | Wide variety of habitats. Riffles and pools of varying depths present. Bends present. | Good variety of habitat e.g. riffles and pools, or bends and pools. Variations in depth of riffles and pools. | Some variety of habitats, e.g. occasional riffle or bend. Some variation in depth. | Uniform, or only slight variety of habitat. All riffles or pools with uniform or only slight variation in depth e.g. channelled stream. |
Interpreting your Results
Habitat Rating | Overall Condition of the Habitat | Colour Code for Map |
Excellent 18–20 | Site in natural or virtually natural condition; excellent habitat condition. | Blue |
Good 13–17 | Some alterations from natural state; good habitat conditions. | Green |
Fair 8–12 | Significant alterations from the natural but still offering moderate habitat; stable. | Yellow |
Poor 5–7 | Significant alterations from the natural state to very degraded. May have moderate to severe erosion or sedimentation problems. | Red |
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Last updated: Thursday, 22-Dec-2005 14:51:24 EST
Waterwatch - communities caring for catchments
Australian Government Department of Sustainability, Environment, Water, Population and Communities
GPO Box 787 Canberra ACT 2601 Australia
Telephone: +61 02 6274 1111
Australian Government Department of Sustainability, Environment, Water, Population and Communities
GPO Box 787 Canberra ACT 2601 Australia
Telephone: +61 02 6274 1111
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