Indicator: IW-10 Assessment of river condition indices
Data
The indices used for assessment of river condition are:
- Annual flow index
- Flow duration index
- Seasonal period index
- Seasonal amplitude index
| Total length of reach (km) in each category and percentage of total in parentheses | Percentage of total length with data | ||||
|---|---|---|---|---|---|
| Largely unmodified | Moderately modified | Substantially modified | Extensively modified | ||
| Queensland | 8 743 (13) | 48 214 (71) | 10 599 (16) | 0 (0) | 93 |
| New South Wales | 1 619 (3) | 39 232 (68) | 17 089 (29) | 18 (0) | 97 |
| Australian Capital Territory | 43 (16) | 191 (71) | 36 (13) | 0 (0) | 100 |
| Victoria | 3 085 (20) | 9 042 (60) | 3 099 (20) | 0 (0) | 97 |
| Tasmania | 2 028 (37) | 3 250 (59) | 194 (4) | 0 (0) | 98 |
| South Australia | 299 (4) | 4 666 (61) | 2 635 (35) | 0 (0) | 79 |
| Western Australia | 1 487 (7) | 15 927 (78) | 2 929 (14) | 12 (1) | 80 |
| Northern Territory | 9 165 (66) | 4 630 (34) | 0 (0) | 0 (0) | 67 |
| Total | 26 468 (14) | 125 152 (66) | 36 581 (19) | 31 (1) | 90 |
Source: National Land and Water Resources Audit 2002, Australian Catchment, River and Estuary Assessment 2002, volumes 1 and 2, Land and Water Australia, Canberra, viewed 13 Dec 2005, http://audit.ea.gov.au/anra//coasts
/docs/estuary_assessment/River_Findings.cfm, Table 12
| River length km | Regulated (unregulated) % | Assessed regulated (unregulated) % | Largely unmodified % | Moderately modified % | Substantially modified % | Extensively modified % | |
|---|---|---|---|---|---|---|---|
| Queensland | 74 475 | 8 (92) | 48 (22) | 86 | 10 | 3 | 1 |
| New South Wales | 62 208 | 18 (82) | 65 (7) | 13 | 66 | 20 | 1 |
| Australian Capital Territory | 283 | 51 (49) | 61 (0) | 0 | 100 | 0 | 0 |
| Victoria | 16 556 | 22 (78) | 70 (7) | 18 | 49 | 30 | 2 |
| Tasmania | 5 843 | 29 (71) | 21 (22) | 6 | 51 | 43 | 0 |
| South Australia | 10 205 | 10 (90) | 48 (31) | 30 | 49 | 16 | 5 |
| Western Australia | 26 900 | 4 (94) | 0 (29) | - | - | - | - |
| Northern Territory | 21 140 | 1 (99) | 0 (90) | - | - | - | - |
| Total | 217 610 | 11 (89) | 54 (26) | 19 | 52 | 28 | 1 |
Source: National Land and Water Resources Audit 2002, Australian Catchment, River and Estuary Assessment 2002, volumes 1 and 2, Land and Water Australia, Canberra, viewed 13 Dec 2005, http://audit.ea.gov.au/anra//coasts/
docs/estuary_assessment/River_Findings.cfm, Table 15.
Regulated reaches are those with a dam or weir upstream.
Unregulated reaches have no major regulating structures upstream, but flow may be affected by extraction for use.
Median monthly flow at Albury, in GL per month
Source: Murray-Darling Basin Ministerial Council 1995, An Audit of Water Use in the Murray-Darling Basin, MDBMC, Canberra, viewed 4 Oct 2005, http://kids.mdbc.gov.au/encyclopedia/water_regulation_and_storage, Figure 14, cited in Source: Murray-Darling Basin Commission, The Impacts of Water Regulation and Storage on the Basin's Rivers, viewed 12 Apr 2005, http://kids.mdbc.gov.au/encyclopedia/water_regulation_and_storage, Figure 6
| Flows under natural conditions, in GL/year | Current flows under regulated conditions, in GL/year | |||
|---|---|---|---|---|
| Mean | Median | Mean | Median | |
| Darling | 3 042 | 1 746 | 2 272 | 1 053 |
| Murrumbidgee | 2 794 | 2 527 | 1 184 | 644 |
| Goulburn, Broken and Campaspe | 3 668 | 3 510 | 1 774 | 1 211 |
| Loddon | 247 | 202 | 100 | 37 |
| Namoi | 872 | 570 | 402 | 177 |
| Gwydir system* | 60 | 11 | 120 | 55 |
| Murray | 13 754 | 11 883 | 4 915 | 2 539 |
Source: Murray-Darling Basin Ministerial Council 1995, An Audit of Water Use in the Murray-Darling Basin, Murray-Darling Basin Commission, Canberra, viewed 23 Nov 2005, http://kids.mdbc.gov.au/encyclopedia/
water_regulation_and_storage, Table1
Median monthly flows - River Murray downstream of the Yarrawonga Weir
Source: Murray-Darling Basin Ministerial Council 1995, An Audit of Water Use in the Murray-Darling Basin, Murray-Darling Basin Commission, Canberra, viewed 23 Nov 2005, http://kids.mdbc.gov.au/encyclopedia/water_regulation_and_storage.
Regulated river reaches below hydroelectric dams with rapid diurnal changes in flow and erratic flow patterns are typically characterised by low diversity macro-invertebrate communities. Sudden increases in flow can cause catastrophic downstream drift to the extent that as much as 14% of the biomass of benthic biota is lost.
Source: Arthington, AH 2002, 'Environmental flows: ecological importance, methods and lessons from Australia', Mekong Dialogue Workshop, "International transfer of river basin development experience: Australia and the Mekong region", vol. 2 September 2002, p. 8.
Victorian River Health Strategy targets
By 2021:
- one major representative river reach in ecologically healthy condition in each major river class
- an increase of 3000 km in the length of rivers in excellent or good condition.
By 2011:
- an improvement in the status of designated freshwater-dependent focal species in each bioregion
- significant improvements achieved in environmental flow regimes of 20 high value river reaches currently flow stressed
- 4800 km of rivers with improvement of one rating in the measurement of riparian condition
- an increase of 7000 ha of riparian areas under management agreements
- 600 km of rivers where instream habitat has been reinstated
- 95% of all highland and upland and 60% of all lowland monitoring sites will meet SEPP environmental quality objectives
- 1000 high value public assets provided with appropriate level of protection.
By 2005:
- an increase in length of river accessible to native fish by an additional 2000 km
- significant improvement in floodplain linkages in ten areas of National and/or State significance
- all rivers with either sustainable catchment limits or negotiated environmental flows in place
- report on the second benchmarking of the environmental condition of Victorian rivers
- a quarter of agricultural production produced from natural resources that are managed within their capacity. By 2015, this will increase to half of agricultural production (as stated in Victoria’s Salinity Management Framework).
Source: Office of the Commissioner for Environmental Sustainability - Victoria (unpubl. Data) 2005, End-of-month water storage volumes for metropolitan Melbourne and rural Victoria, July 2000-Nov 04, Contact Person: Jane Tovey Program Manager, Office of the Commissioner for Environmental Sustainability, Email: Jane.Tovey@ces.vic.gov.au, viewed N/A, www.ces.vic.gov.au.
What the data mean
The examples provided indicate lower annual river flows than naturally occurring flows and that seasons of greatest flow are inverted.
Eighty five percent of the river length are substantially or moderately modified from their natural condition. In the Northern Territory, two-thirds of the river length assessed is largely unmodified. In all other States and Territories except Tasmania, more than 80% of the river length assessed is substantially or moderately modified.
Almost 90% of river length is unregulated.
Data Limitations
The NLWRA data has not been updated since 2001.
The examples provided on flow conditions may not necessarily reflect conditions of other rivers.
Issues for which this is an indicator and why
Inland Waters - Catchment scale influences - Hydrological condition - Ecological aspects of river flow regimes
The component parts of this indicator provide a broad insight into the condition of river systems in respect to several aspects of flow regimes.
Other indicators for this issue:
- IW-11 Number of licences dams, weirs, regulators and levees
- IW-26 Forested streamlength
- IW-27 Extent of significant wetlands (incl. Ramsar)
- IW-28 Number of effective fishways
- IW-44 Sustainable yield determination
- IW-46 Implementation of COAG principles
- HS-42 Water consumption per capita
Inland Waters - Response of biota - Macroinvertebrates
The component parts of this indicator provide a broad insight into the condition of river systems in respect to several aspects of flow regimes, and therefore indirectly into the condition of macroinvertebrates.
Other indicators for this issue:
Inland Waters - Human response - policy and management - Environmental flows allocation and management
The component parts of this indicator provide a broad insight into the condition of river systems in respect to several aspects of flow regimes, and therefore into the effectiveness of management responses to the pressures of changes in flow regimes.
Other indicators for this issue:
- IW-11 Number of licences dams, weirs, regulators and levees
- IW-43 Implementation of National Water Initiative
- IW-44 Sustainable yield determination
- IW-46 Implementation of COAG principles
Biodiversity - Pressures on biodiversity - Changed hydrology
River and stream flows are affected by weirs and dams and water diversions. Aquatic biodiversity and species that rely on water resources for food, such as waterbirds, are affected by the reduced availability of water. The component parts of this indicator provide a broad insight into the condition of river systems in respect to several aspects of flow regimes, and therefore into these pressures on biodiversity.
Other indicators for this issue:
- BD-14 Examples of impacts of changed hydrology on biodiversity
- LD-06 Area and proportion of land affected by dryland salinity and acidity
- IW-05 Average annual groundwater depth
- IW-06 Average annual groundwater pressure
- IW-26 Forested streamlength
- IW-27 Extent of significant wetlands (incl. Ramsar)
- IW-28 Number of effective fishways
- IW-33 Abundance and distribution of waterbirds
- IW-46 Implementation of COAG principles
Natural and Cultural Heritage - Knowledge of heritage - Listing processes, number and distribution of identified heritage items (places and objects)
The component parts of this indicator provide a broad insight into the condition of river systems in respect to several aspects of flow regimes, and therefore help define the natural heritage aspects of river systems.
Other indicators for this issue:
- NCH-01 Process of listing, area and distribution of identified natural heritage places
- NCH-02 Process of listing, area and distribution of Indigenous heritage listings
- NCH-03 Process of listing, area and distribution of identified historic heritage places
- NCH-04 Process of listing, area and distribution of significant heritage objects
- IW-34 Examples of deterioration of condition of wetland vegetation
- BD-02 Conservation status of nationally significant species and ecological communities, compared with previous years
- BD-04 Listed threatened species or ecological communities for which recovery action is showing stable or increasing populations
- BD-07 Examples of Indigenous knowledge of species and ecological communities and their utilisation for management by Indigenous and non-Indigenous managers and for other purposes by Indigenous and non-Indigenous people
Further Information
Key
Links to another web site
Links to data in the DRS
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