Principal Investigators: M. Thoms and R. Norris
Research Officers: M. Parsons and G. Ransom
Cooperative Research Centre for Freshwater Ecology
Monitoring River Health Initiative Technical Report Number 23
Environment Australia, 2002
ISSN 1447 1280
ISBN 0 642 54889 7
| Variable category and description | Source | Workshop group recommendation | Notes |
|---|---|---|---|
| GEOGRAPHICAL POSITION | |||
| Altitude | AusRivAS variable | 6B2 YES, 6B9 NO | Debate about whether geographic position variables tell you anything about stream condition. However, they may place the site into its catchment context which is important biologically and geomorphologically |
| Latitude | AusRivAS variable | 6B2 YES, 6B9 NO | As above |
| Longitude | AusRivAS variable | 6B2 YES, 6B9 NO | As above |
| Catchment area upstream | AusRivAS variable | 6B2 YES, 6B9 NO | As above, but may be more relevant to geomorphological process |
| Distance from source | AusRivAS variable | 6B2 YES, 6B9 NO | As above, but may be more relevant to geomorphological process |
| Channel slope | AusRivAS variable - some States only | 6B2 YES, 6B9 YES | Important geomorphological variable. Probably misplaced in geographical position category, should be in channel morphology. |
| Valley confinement | Suggested in workshop | Useful for indicating differences in stream power between confined, floodplain and broad sections. Misplaced in geographical position category, should probably be in channel morphology category. | |
| RIPARIAN VEGETATION | |||
| Width of riparian zone | AusRivAS variable | 6B2 YES, 6B9 YES | Riparian vegetation was considered an important aspect both ecologically and geomorphologically |
| Cover of riparian zone by trees, shrubs, grasses | AusRivAS variable | 6B2 YES, 6B9 YES | As above |
| Canopy cover of river | AusRivAS variable | 6B2 YES, 6B9 YES | As above |
| Native and exotic vegetation cover | AusRivAS | variable 6B2 YES, 6B9 YES | As above |
| Riparian vegetation density | AusRivAS variable - some States only | 6B2 YES, 6B9 YES | As above |
| Riparian vegetation continuity | AusRivAS variable - some States only | 6B2 YES, 6B9 YES | As above |
| Riparian vegetation stability, density, composition, continuity | Suggested at workshop | May need to involve botanist for suggestions on the types of floristic variables that may be relevant. | |
| Evidence of regeneration | Suggested at workshop | This variable is measured in the ISC. | |
| CHANNEL MORPHOLOGY | |||
| Stream width | AusRivAS variable | 6B2 YES, 6B9 YES | More important for ecology than for geomorphology |
| Stream depth | AusRivAS variable | 6B2 YES, 6B9 YES | More important for ecology than for geomorphology |
| Bank width | AusRivAS variable | 6B2 YES, 6B9 YES | Important geomorphologically |
| Bank height | AusRivAS variable | 6B2 YES, 6B9 YES | Important geomorphologically |
| Width:depth ratio | Suggested at workshop | May be an indicator of incision. If relating to catchment dimensions, width and depth measurements need to be taken at many places along a stream reach. Also may need to make these measurements relative to the water mark. | |
| Bed heterogeneity | Suggested at workshop | Scale of focus? Bed heterogeneity can be measured at a small microscale or at a reach scale. May also link to the measure of channel complexity below. Can Mannings n be used as a measure of heterogeneity? | |
| Bed form assessment | Suggested at workshop (6B2) | Is a measure of the types of bedfoms (glides, runs, pools etc.) present. | |
| Channel complexity | Suggested at workshop | Not sure exactly what this would comprise, or at which scale. Perhaps a measure of wetted channel complexity or an index of channel shape. Rebecca Bartley may be a good contact for this. | |
| Erosion (local and catchment) | Suggested at workshop (6B2) | Would be a measure of the extent of local and catchment erosion. Perhaps covered by bed and bank stability measures? | |
| ISC measurements, especially physical form sub-indices of bed stability, bank stability and instream physical habitat | Suggested at workshop | Represents geomorphological processes. Field interpretation may need to be aided by photographs (see ISC field manual). | |
| River braiding and bars | Suggested at workshop although is included in AusRivAS observations - some States only | Unclear about what this indicates about stream morphology. | |
| Bank shape | Suggested at workshop | To indicate undercutting etc. This variable is measured in the River Habitat Audit Procedure | |
| Longitudinal variability | Suggested at workshop | Probably measured within the sampling reach. See Rebecca Bartley for more details. | |
| WATER CHEMISTRY | |||
| Temperature | AusRivAS variable | 6B2 YES, 6B9 YES | Should also record time of day. Temperature probably not useful in itself but may be needed to calibrate other measurements |
| Conductivity | AusRivAS variable | 6B2 YES, 6B9 YES | Reflects catchment geology |
| pH | AusRivAS variable | 6B2 YES, 6B9 YES | |
| Dissolved oxygen | AusRivAS variable | 6B2 YES, 6B9 YES | |
| Turbidity | AusRivAS variable | 6B2 YES, 6B9 YES | |
| Alkalinity | AusRivAS variable | 6B2 YES, 6B9 YES | Reflects catchment geology |
| Nutrients | AusRivAS variable | 6B2 NO, 6B9 YES | Debate about usefulness of instantaneous measurements. Probably not worth collecting as spot measures. Other indicators (e.g. algae) may provide an integrated assessment of nutrient levels. |
| Ammonium | AusRivAS variable - some States only | 6B2 NO, 6B9 YES | Again, debate about usefulness of instantaneous measurements. |
| Air temperature | AusRivAS variable - some States only | 6B2 NO, 6B9 NO | Can be discarded |
| Stratification | Suggested at workshop (6B2) | May be useful in lowland rivers, especially in deep pools. | |
| HABITAT COMPOSITION | |||
| Large woody debris | Suggested in workshop (6B2) | Important variable ecologically and geomorphologically. Not covered well in AusRivAS. | |
| Percent riffle, edge, pool, macrophytes, run, snags and or dry bed in sampling area . | AusRivAS variables | Mixed support. Important as a measure of macroinvertebrate habitat availability, but may not be the most geomorphologically relevant 'units' to measure | Perhaps better covered in a bedform assessment (see channel morphology section) with units that are important geomorphologically. However, the current units are important because they (runs, pools, riffles etc.) represent the availability of the habitat types sampled for macroinvertebrates. |
| HYDROLOGY | |||
| Mean annual discharge | AusRivAS variable | 6B2 MIXED SUPPORT, 6B9 YES | Generally useful ecologically (i.e. how big is the stream) but not useful geomorphologically |
| CV of variation of mean annual discharge | AusRivAS variable | 6B2 YES, 6B9 YES | Useful as a measure of variability over time |
| Stream power | Suggested in workshop (6B2) | Not discussed in detail, Chris Gippel may provide some insight | |
| Time since last flood | Suggested in workshop (6B2) | This is the Thoms silt trembler and gooley shaker idea! The time since the last flood with a force that moved silt or larger particles along the streambed | |
| Measure of ephemerality | Suggested in workshop (6B2) | Represents the ephemerality of flow and should indicate the difference between permanent and temporary streams. Is probably not the same thing as seasonal variation in flow? | |
| Hydraulic variability | Suggested in workshop (6B2) | Is a measure of the different hydraulic 'types' present in a reach. When considered alongside substratum, hydraulic variability may provide a rough measure of channel hydraulic complexity. | |
| Cease to flow | Suggested in workshop (6B2 and 6B9) | Probably obtained off flow duration curves. | |
| Overbank flows | Suggested in workshop | Related to floodplain processes | |
| Flow seasonality | Suggested in workshop | Is a measure of seasonal variation in flows. Represents differences in summer and winter rainfall areas? | |
| Change in flood frequency | Suggested in workshop | Would need to be compared to natural conditions? | |
| Note on hydrology: There are hundreds of hydrological measurements that could be included in the protocol, including those from the ISC (see back pages of ISC reference manual). There needs to be a closer consideration of the information that is required from the hydrological measurements, so that the appropriate measures can be collected. Concern was also raised about the difficulty of obtaining hydrological data and also about the lack of relationships that hydrological data generally has with macroinvertebrate data. However, hydrological data was considered to be critical to the assessment protocol because geomorphological changes tend to occur under high flow events. |
|||
| INORGANIC SUBSTRATUM | |||
| Bedrock | AusRivAS variable | 6B2 YES, 6B9 NO | Both groups agreed that substratum was important geomorphologically and ecologically. However, group 6B9 did not think that it could tell us something about condition relative to pristine. Substratum process measurements may be more important geomorphologically whereas substrate composition may be important ecologically. It was agreed that the small fractions should be included because they were important ecologically and geomorphologically. It may also be relevant to take surface and sub-surface measurements because biota use both layers of substratum. |
| Boulder | AusRivAS variable | 6B2 YES, 6B9 NO | As above |
| Cobble | AusRivAS variable | 6B2 YES, 6B9 NO | As above |
| Pebble | AusRivAS variable | 6B2 YES, 6B9 NO | As above |
| Gravel | AusRivAS variable | 6B2 YES, 6B9 NO | As above |
| Sand | AusRivAS variable | 6B2 YES, 6B9 NO | As above |
| Silt/Clay | AusRivAS variable | 6B2 YES, 6B9 NO | As above |
| Substratum heterogeneity | AusRivAS variable - some States only | 6B2 YES, 6B9 NO | Integrates the composition of each substrate component into an overall measure of heterogeneity? |
| Armouring | Suggested in workshop (6B2) | Is a measure of the potential for the stream bed to move under high flow conditions. | |
| Matrix characteristics | Suggested in workshop (6B2) | Measures the matrix sediment and the fines component (Martin's idea). Is based in sediment theory. | |
| Detritus cover (CPOM and FPOM) | AusRivAS variable | YES 6B2, NO 6B8 | Group 6B9 thought that this was unable to indicate condition relative to pristine. But 6B9 thought that it was important to indicate condition. Unclear of the geomorphological relevance of detritus cover, except perhaps as an indicator of bed stability. |
| Moss cover | AusRivAS variable | YES 6B2, NO 6B9 | Group 6B9 thought that moss was unable to indicate condition relative to pristine. The ecologists in group 6B2 couldn't work out why moss was important ecologically. However, the geomorphologists thought that moss was important because it could indicate the time since the last stream bed disturbance event that moved particles along the bed. |
| Filamentous algae cover | AusRivAS variable | YES 6B2, NO 6B10 | Group 6B9 thought that this was unable to indicate condition relative to pristine. But 6B9 thought that it was an important variable for indicating condition. |
| Macrophyte cover | AusRivAS variable | YES 6B2, NO 6B11 | Group 6B9 thought that this was unable to indicate condition relative to pristine. But 6B9 thought that it was important to indicate condition. Unclear of geomorphological relevance, except perhaps as an indicator of bed stability. |
| Periphyton cover | AusRivAS variable | YES 6B2, NO 6B12 | Group 6B9 thought that this was unable to indicate condition relative to pristine. But 6B9 thought that it was important to indicate condition. Unclear of geomorphological relevance, except perhaps as an indicator of bed stability. |
| Macrophyte architecture | Suggested in workshop (6B2) | Indicates macrophytes as a habitat for macroinvertebrates. The complexity of macrophyte architecture may be related to species diversity. | |
| Large woody debris | Suggested in workshop (6B2) | See notes in habitat composition section above | |
| USEPA HABITAT ASSESSMENT | |||
| Bottom substrate / available cover | AusRivAS variable | 6B9 not considered, 6B2 unresolved | Unclear as to whether habitat assessment variables are important geomorphologically. Ecologically, they are important because they place a condition rating on whether each habitat parameter is able to support biological communities. |
| Embeddedness | AusRivAS variable | 6B9 not considered, 6B2 unresolved | As above |
| Velocity / depth category | AusRivAS variable | 6B9 not considered, 6B2 unresolved | As above |
| Channel alteration | AusRivAS variable | 6B9 not considered, 6B2 unresolved | As above |
| Bottom scouring and deposition | AusRivAS variable | 6B9 not considered, 6B2 YES | As above. However, bottom scouring and deposition score is probably misplaced here and should be with channel morphology variables. |
| Pool/riffle, run/bend ratio | AusRivAS variable | 6B9 not considered, 6B2 YES | As above. However, pool/riffle ratio score is probably misplaced here and should be with channel morphology variables. |
| Bank stability | AusRivAS variable | 6B9 not considered, 6B2 YES | As above. However, bank stability score is probably misplaced here and should be with channel morphology variables. |
| Bank vegetative stability | AusRivAS variable | 6B9 not considered, 6B2 unresolved | As above |
| Streamside cover | AusRivAS variable | 6B9 not considered, 6B2 unresolved | As above |
| Total habitat score | AusRivAS variable | 6B9 not considered, 6B2 unresolved | As above |
| SITE OBSERVATIONS | |||
| Water and sediment odours and oils | AusRivAS variable | 6B9 not considered, 6B2 unresolved | May be important biologically, but what can it tell us geomorphologically? Might be an important indicator of severe pollution. |
| Flow level and restrictions | AusRivAS variable | 6B9 not considered, 6B2 NO | A coarse measurement that may only be applicable locally. May be better measured on a larger scale using hydrological data. |
| Kicknetting plume | AusRivAS variable | 6B9 not considered, 6B2 NO | Relevance is limited to macroinvertebrate collection. This variable indicates the amount of fines, which would be picked up by other substratum variables. Thus, kicknetting plume can be discarded. |
| Local bank and catchment erosion | AusRivAS variable | 6B9 not considered, 6B2 YES | Important geomorphological variable. Included in channel morphology section above. |
| Landuse | AusRivAS variable | 6B9 not considered, 6B2 NO | Not sure about this one. Landuse is probably a large-scale factor that influences a range of smaller scale factors. Thus, landuse can be measured on a catchment wide or local reach scale. Landuse would need to be included in a predictive modelling approach. This variable also gives scope to include man in the landscape and move away from notions of pristine condition. |
| Valley topography | AusRivAS variable | 6B9 not considered, 6B2 YES | Should be changed slightly to valley confinement. Valley confinement is included in geographical position section above. |
| River braiding and bars | AusRivAS variable | 6B9 not considered, 6B2 YES | Important geomorphological variable. Included in channel morphology section above. |
| Local point source and non-point source pollution | AusRivAS variable | 6B9 not considered, 6B2 NO | Probably more important biologically, but still only used for interpretation. Can be discarded. |
| OTHER VARIABLES | |||
| Overhanging vegetation | AusRivAS edge habitat variable | 6B9 not considered, 6B2 not considered | Probably doesn't need to be measured because it is specific to the edge habitat. However, a measure of the degree of trailing bank vegetation in slow flowing areas might be included under the riparian vegetation category. |
| Water velocity | AusRivAS variable | No real conclusions reached Probably important information for distinguishing between habitats and between different stream gradients for macroinvertebrates. However, it is probably of limited use geomorphologically, because geomorphology is concerned with high flow events and whole stream discharges. Also, 3 or 4 replicate velocity measurements may not be adequate to characterise hydraulic conditions. | |
| Floodplain characteristics such as condition, erosion, sedimentation, connectivity to main channel, frequency of innundation | Suggested at workshop (6B2) | Not so important for AusRivAS but important geomorphologically. | |
| Catchment geology | Suggested at workshop (6B2) | Important geomorphologically, at a large-scale. There may also be other large-scale 'control' type variables that can be measured. See Nerida's study for ideas. | |