|
|
|
|
|
Without good baseline information we can not properly set long term management objectives for our rivers or determine priorities for action. We also have no way of knowing if our actions are successful. The Index of Stream Condition (ISC) was developed to assist in assessing river condition. The ISC is an integrated tool for catchment management that can assist Catchment Management Authorities together with their regional communities to set management objectives and measure the effectiveness of long term programs for the rivers in their catchment. The ISC is an indicator of environmental condition that integrates information of the major components of our river systems that are important from an ecological perspective. It brings together information on the current river flow regime, water quality, condition of the channel and riparian zone and the invertebrate communities living in the stream. It provides an overall indication of changes in river condition. The ISC benchmarking is a snapshot of river condition during 1999. It should be noted that the ratings reflect river condition in this year only. 950 river reaches representing 18 000km of Victoria’s major rivers and their tributaries were surveyed.
|
|||||||||||||
|
Objectives The two main objectives of the ISC are to:
The 5 Sub-indices The ISC contains 5 sub-indices. These five sub-indices are made up of a total of 19 key indicators. The ISC provides a summary of the extent of change from natural or ideal conditions to each of the 5 sub-indices: > hydrology (flow volume and seasonality of flow) > physical form (stream bank and bed condition, presence of and access to physical habitat) > streamside zone (quality and quantity of streamside vegetation and condition of billabongs) > water quality (nutrient concentration, turbidity, salinity and acidity), and > aquatic life (diversity of macroinvertebrates)
Calculating the ISC score Each sub-index is scored out of a maximum of ten. An inverse ranking is then applied to the sub-index scores. The total score is then scaled back to a maximum value of 50. Thus the overall score for the ISC will vary between a minimum of 0 and a maximum of 50. When either/ or the water quality/ aquatic life sub-index scores are missing (ie. no data available) these are estimated on a pro rata basis so as to allow the aggregated ISC score to be calculated. Where pro rata values have been used, an asterix is attached to the aggregated ISC score. Condition
ratings The
condition of reaches can been classified into one of five
classifications:
The maximum amount of
information can be extracted from the ISC by looking at the individual Publications A
number of publications are available which have detailed information on
how the ISC was developed and applied: Index
of Stream Condition: Reference Manual (second edition) details
how the ISC was developed and applied along with details of each
sub-index. Index
of Stream Condition: Field Manual details procedures for the collecting of field data to evaluate
indicators in the Streamside zone and Physical form sub-indices. Index
of Stream Condition: Catchment managers manual provides
advice on how ISC results can be interpreted and used in strategic
waterway management. Index
of Stream Condition: Users Manual (second edition)
how to undertake data collection and data entry for the ISC (early
2001). Victorian
Rivers: An Environmental Report Card is
a brochure introducing the web site and major findings Further
information For more detailed information please contact: Paul Wilson at the Department of Sustainability and Environment phone:
03 9637 9968 e-mail:
paul.wilson@dse.vic.gov.au |
