No modifications
Melissa Parsons, Martin Thoms and Richard Norris
Cooperative Research Centre for Freshwater Ecology
University of Canberra
Monitoring River Health Initiative Technical Report Number 22
Environment Australia, 2002
ISSN 1447-1280
ISBN 0 642 54888 9
| VARIABLE NAME | USEPA Habitat Assessment High Gradient Streams |
| CATEGORY | Physical condition indicators and habitat assessment |
| CONTROL OR RESPONSE | Response |
| OFFICE OR FIELD | Field |
| UNITS OF MEASUREMENT | Score (0-20) for each habitat assessment parameter
Score (out of 200) for the overall habitat assessment |
| INDICATES | Overall condition assessment incorporating a range of parameters that emphasise biologically significant aspects of the stream habitat (Barbour et al., 1999) |
The USEPA habitat assessment for high gradient streams should be used in streams located in moderate to high gradient landscapes, with substrates composed predominantly of coarse sediment particles (ie. gravel or larger) or frequent coarse particulate aggregations (Barbour et al., 1999). These types of streams will be found predominantly in low energy unconfined and high energy confined zones (see Part 2).
The high gradient habitat assessment contains 10 parameters (Table 5.2), each of which is considered a separate variable for the purposes of the physical assessment protocol. Each habitat assessment parameter is visually assessed at each high gradient sampling site, and scored according to a continuum of conditions ranging from poor through to excellent. These poor, marginal, sub-optimal and optimal categories are used as a guide to assign each parameter a score between 1-20. Low scores are indicative of poor or degraded habitat conditions. A total habitat assessment score is also calculated as the sum of the scores for each parameter.
Details of the observable states that comprise each condition category for each parameter are provided on the data sheets. More information, including explanatory photographs, can be obtained from Barbour et al. (1999) or from the USEPA website at http://www.epa.gov/owow/monitoring/rbp/
| Parameter | Broad description and ecological relevance |
|---|---|
| Epifaunal substrate / available cover | Includes the relative quantity and variety of natural structures in the stream such as cobble (riffles), large rocks, fallen trees, logs and branches that are available as refugia, feeding or spawning/nursery sites for aquatic macrofauna. A wide variety or abundance of submerged structures in the stream provides macroinvertebrates and fish with a large number of niches, thus increasing habitat diversity. |
| Embeddedness | Refers to the extent to which rocks (gravel, cobble and boulders) and snags are covered by, or sunken into, the silt, sand or mud of the stream bottom. Generally, as rocks become embedded, the surface area available to macroinvertebrates and fish (spawning, shelter and egg incubation) is decreased. |
| Velocity / depth regime | The occurrence of slow-deep, slow-shallow, fast-deep and fast-shallow velocity patterns relates to habitat diversity and the ability of the stream to provide and maintain a stable aquatic habitat. |
| Sediment deposition | Measures the amount of sediment that has accumulated in pools and the changes that have occurred to the stream bottom as a result of deposition. High levels of sediment deposition are symptoms of an unstable and continually changing environment that becomes unsuitable for many organisms. |
| Channel flow status | Measures the degree to which the channel is filled with water. The flow status will change as the channel enlarges (e.g. aggrading streambeds with actively widening channels) or as flow decreases because of dams, diversions or drought. When water does not cover much of the streambed, the amount of suitable habitat for aquatic organisms is reduced. |
| Channel alteration | Is a measure of large scale changes in the shape of the stream channel. Straightened or altered channels have fewer natural habitats for aquatic organisms than do naturally meandering streams. |
| Frequency of riffles (or bends) | Measures the sequence of riffles or bends. Riffles are a source of high quality habitat and diverse fauna and therefore, an increased frequency of occurrence greatly enhances the diversity of the stream community. For high gradient streams where distinct riffles are uncommon, a run/bend ratio can be used as a measure of habitat availability. |
| Bank stability | Measures whether the stream banks are eroded, or have the potential for erosion. Steep banks are more likely to collapse and suffer from erosion than gently sloping banks. |
| Bank vegetative protection | Measures the amount of vegetative protection afforded to the stream bank and the near-stream portion of the riparian zone. The root systems of plants growing on stream banks help hold soil in place, thereby reducing the amount of erosion that is likely to occur. |
| Riparian vegetative zone width | Measures the width of natural vegetation from the edge of the stream bank out through the riparian zone. The vegetative zone serves as a buffer to pollutants entering a stream from runoff, controls erosion and provides habitat and nutrient input to the stream. |
| Total habitat score | Overall assessment of habitat condition. Calculated as the sum of the scores for each of the 10 habitat assessment parameters. |
| VARIABLE NAME | USEPA Habitat Assessment Low Gradient Streams |
| CATEGORY | Physical condition indicators and habitat assessment |
| CONTROL OR RESPONSE | Response |
| OFFICE OR FIELD | Field |
| UNITS OF MEASUREMENT | Score (0-20) for each habitat assessment parameter
Score (out of 200) for the overall habitat assessment |
| INDICATES | Overall condition assessment incorporating a range of parameters that emphasise biologically significant aspects of the stream habitat (Barbour et al., 1999) |
The USEPA habitat assessment for low gradient streams should be used in streams located in low to moderate gradient landscapes, with substrates composed predominantly of fine sediment or infrequent aggregations of coarse (gravel or larger) sediment particles (Barbour et al., 1999). These types of streams will be found predominantly in transition and lower zones (see Part 2).
The low gradient habitat assessment contains 10 parameters (Table 5.3), each of which is considered a separate variable for the purposes of the physical assessment protocol. Each habitat assessment parameter is visually assessed at each low gradient sampling site, and scored according to a continuum of conditions ranging from poor through to excellent. These poor, marginal, sub-optimal and optimal categories are used as a guide to assign each parameter a score between 1-20. Low scores are indicative of poor or degraded habitat conditions. A total habitat assessment score is also calculated as the sum of the scores for each parameter.
Details of the observable states that comprise each condition category for each parameter are provided on the data sheets. More information, including explanatory photographs, can be obtained from Barbour et al. (1999) or from the USEPA website at http://www.epa.gov/owow/monitoring/rbp/
| Parameter | Broad description and ecological relevance |
| Epifaunal substrate / available cover | Includes the relative quantity and variety of natural structures in the stream such as cobble (riffles), large rocks, fallen trees, logs and branches that are available as refugia, feeding or spawning/nursery sites for aquatic macrofauna. A wide variety or abundance of submerged structures in the stream provides macroinvertebrates and fish with a large number of niches, thus increasing habitat diversity. |
| Pool substrate characterisation | Evaluates the type and condition of bottom substrates found in pools. Firmer sediment types (gravel, sand) and rooted aquatic plants support a wider variety of organisms than a pool substrate dominated by mud or bedrock and no aquatic plants. |
| Pool variability | Rates the overall mixture of pool types found in streams, according to size and depth. A stream with many pool types will support a wide variety of aquatic species. |
| Sediment deposition | Measures the amount of sediment that has accumulated in pools and the changes that have occurred to the stream bottom as a result of deposition. High levels of sediment deposition are symptoms of an unstable and continually changing environment that becomes unsuitable for many organisms. |
| Channel flow status | Measures the degree to which the channel is filled with water. The flow status will change as the channel enlarges (e.g. aggrading streambeds with actively widening channels) or as flow decreases because of dams, diversions or drought. When water does not cover much of the streambed, the amount of suitable habitat for aquatic organisms is reduced. |
| Channel alteration | Is a measure of large scale changes in the shape of the stream channel. Straightened or altered channels have fewer natural habitats for aquatic organisms than do naturally meandering streams. |
| Channel sinuosity | Evaluates the meandering or sinuosity of the stream. A high degree of sinuosity provides for diverse habitat and fauna, and the stream is better able to handle surges when the stream fluctuates as a result of storms. |
| Bank stability | Measures whether the stream banks are eroded, or have the potential for erosion. Steep banks are more likely to collapse and suffer from erosion than gently sloping banks. |
| Bank vegetative protection | Measures the amount of vegetative protection afforded to the stream bank and the near-stream portion of the riparian zone. The root systems of plants growing on stream banks help hold soil in place, thereby reducing the amount of erosion that is likely to occur. |
| Riparian vegetative zone width | Measures the width of natural vegetation from the edge of the stream bank out through the riparian zone. The vegetative zone serves as a buffer to pollutants entering a stream from runoff, controls erosion and provides habitat and nutrient input to the stream. |
| Total habitat score | Overall assessment of habitat condition. Calculated as the sum of the scores for each of the 10 habitat assessment parameters. |
| VARIABLE NAME | Channel modifications |
| CATEGORY | Physical condition indicators and habitat assessment |
| CONTROL OR RESPONSE | Response |
| OFFICE OR FIELD | Field |
| UNITS OF MEASUREMENT | Choice of twelve categories |
| INDICATES | Human induced changes to the channel |
At each sampling site, indicate the presence of channel modifications corresponding to one or more of the following categories:
|
Natural No modifications |
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Reinforced |
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Desnagged | |
Revegetated |
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Dams and diversions | |
Infilled |
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Resectioned | |
Berms1 or embankments |
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Straightened | Signs of work still visible | Recently channelised |
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Realigned | Works old and vegetated | Channelised in the past |
Variable derived from the River Habitat Audit Procedure (Anderson, 1993a).
1. A berm is a natural or artificial levee, dike, shelf, ledge, groyne or bench along a streambank that may extent laterally along the channel or parallel to the flow to contain the flow within the streambank (Armantrout, 1998).
| VARIABLE NAME | Artificial features |
| CATEGORY | Physical condition indicators and habitat assessment |
| CONTROL OR RESPONSE | Response |
| OFFICE OR FIELD | Field |
| UNITS OF MEASUREMENT | Choice of six categories |
| INDICATES | Presence of artificial features in the stream |
At each sampling site, indicate the presence of one or more of the following artificial features within the channel:
| Category | Examples1 |
|---|---|
| major weir | Concrete, stone or rubble weir across the entire width of channel that substantially modifies stream flow. |
| minor weir | Concrete, stone or rubble weir that only partially modifies stream flow. |
| culvert | Arched pipeline or channel for carrying water beneath and road or railway. |
| bridge | Small or large bridge within the area of the sampling site |
| ford | Road or stock crossing passing through the stream. May be constructed of concrete or streambed materials. |
| other | State other structures present in the stream channel (e.g. aboriginal fish traps, jetties, boat ramps etc.) |
Additionally, record a description of the types of structures present within the length of the sampling site. For example, a minor weir present at a sampling site may be a set of concrete stepping-stones across a stream in an urban area, or a ford may be a fire trail crossing through a stream in a National Park.
Include only local features in this variable. Do not include major impoundments, unless the sampling site is immediately upstream or downstream of a major impoundment structure.
Variable modified from the River Habitat Survey (Raven et al., 1998)
1. Examples are not exhaustive
| VARIABLE NAME | Physical barriers to local fish passage |
| CATEGORY | Physical condition and habitat assessment |
| CONTROL OR RESPONSE | Response |
| OFFICE OR FIELD | Field |
| UNITS OF MEASUREMENT | Choice of six categories |
| INDICATES | Potential of the sampling site to allow native fish migration under low flow, base flow and high flow conditions. |
At each sampling site, visually assess the potential for the migratory passage of fish along the length of the sampling site under low flow, base flow and high flow conditions. Physical barriers that may inhibit fish passage through the reach include weirs, fords and culverts, sediment slugs (e.g. sand slugs), log jams and waterfalls. Do not include the effects of major impoundments in this variable.
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No passage No connectivity between pools | At each sampling site, make a separate assessment of the potential for the passage of fish through the length of the sampling site under:
In otherwords, how 'easy' would it be for a fish to travel through the length of the sampling site under base flow, low flow and high flow conditions? Choose one category only for each sampling site and each flow condition. In the diagrams opposite, the white patches represent water and the textured patches represent obstructions. Also record the type of physical barriers that are present within a sampling site (e.g. sand slug, culvert etc.) |
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Very restricted passage
Low connectivity between pools | |
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Moderately restricted passage
Moderate connectivity between pools | |
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Partly restricted passage
Localised obstructions present but overall passage through reach possible | |
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Good passage
Most of the channel area unobstructed | |
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Unrestricted passage
All of the channel area unobstructed |
1 Base flow level is identified by the limit of terrestrial grasses, eroded area or the boundary of bank sediment types. Low flow level is equivalent to the reduction in flow that would occur during the dry season or during a drought. High flow level is equivalent to the bankfull capacity of the channel.
Variable derived from the River Habitat Audit Procedure (Anderson, 1993a).
| VARIABLE NAME | Planform channel pattern |
| CATEGORY | Planform channel features |
| CONTROL OR RESPONSE | Response |
| OFFICE OR FIELD | Office |
| UNITS OF MEASUREMENT | Choice of ten categories |
| INDICATES | The type of channel present, which in turn is related to flow dynamics and sediment relations. |
Assign the type of channel present along the segment (see channel slope variable) within which the sampling site sits, into one of the following categories. It is important to interpret this variable with the aid of maps and aerial photos, because planform pattern is difficult to decipher locally in the field. However, braided, anastomosing, swampy and overland channel patterns should be verified in the field when visiting the sampling site.
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Straight Very little curvature |
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Mildly sinuous Mild curvature |
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Irregular Irregular sinuous channel that displays irregular turns and bends without repetition of similar features |
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Regular meanders A clear repeated meander pattern formed in a simple channel that is well-defined by cutting outside of a bend |
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Irregular meanders Meander pattern is repeated irregularly |
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Tortuous A repeated pattern characterised by angles greater than 90o |
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Braided Multiple channels that divide into a network of branching and reuniting channels. Channels are separated from each other by mobile bars or islands. Channel sediment is generally coarse (sand and gravel). Bankfull level is not well defined. |
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Anastomosing Multiple channels (main and anabranch) that divide into a network of branching and reuniting channels. Channels are separated from each other by stable islands, that are relatively wide in comparison to the channel and which are usually vegetated. Channel sediment is generally fine (sand, silt and clay). Bankfull level of each channel is well defined, but the whole system sits within a wide floodplain. |
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Swampy Swampy areas of the river system characterised by low gradient but permanent sub-surface or surface water flow |
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Channelised A channel that has been artificially straightened |
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Overland Overland flow not contained within a well defined channel |
Variable derived from the River Habitat Audit Procedure (Anderson, 1993a).