Gundagai
Indicator: Riparian Conditions
Results for this indicator are also available for [an error occurred while processing this directive]
What the results tell us for Gundagai
No quantitative information was available to assess changes in the condition of riparian areas within the Gundagai Shire during the current reporting period and the previous reporting period. This current reporting period has seen six threatening processes which impact on riparian condition which were listed under the Threatened Species Conservation Act, 1995 and the Fisheries Management Act, 1994.
It is not known if the Shire or community groups undertook any projects between July 2004 and June 2008 to rehabilitate riparian areas within the Shire.
This is the second reporting period for which Gundagai Shire has been included in the Australian Capital Region State of the Environment Report (RSoER) and as such, there continues to be no comparative data available for comparing trends over the previous reporting periods.
Condition of riparian zones in the Shire
The extent to which the condition of riparian vegetation and streambank disturbance across the Shire changed in the current reporting period is not known, as no comprehensive assessment of riparian condition was undertaken for the period and no other detailed Shire-wide information was available.
During the previous reporting period River Red Gum (Eucalyptus camaldulensis) forest was said to be the main riparian vegetation community in Gundagai Shire (Mulvaney et al. 2005). This community was 94% cleared within the Shire and only a thin strip remains along the Murrumbidgee River. Most remnants of this community were highly degraded and weeds dominate the understorey (Mulvaney et al. 2005 in OCE 2004).
The Shire reported, during the previous reporting period, that due to regulation on the Murrumbidgee River, extensive summer erosion occurs from extended periods of high water flow which undercuts the river banks, and extensive winter erosion occurs from the dry river banks collapsing when water flow is restricted for storage purposes (Moore 2005 in OCE 2004).
Threats to riparian condition
Three processes relating to riparian condition have been listed as key threatening processes in the State (see Table 1) by the New South Wales (NSW) Scientific committee under the Threatened Species Conservation Act 1995. Fisheries Scientific Committee also listed, under the Fisheries Management Act 1994, three key threatening processes relevant to riparian areas.
| Name of threatening process | Date of Final Determination or Gazettal |
|---|---|
| Alteration to the natural flow regimes of rivers, streams, floodplains and wetlans (DECC, 2008a) | Final: 31 May 2002 |
| Clearing of Native Vegetation (DECC, 2008b) | Final: 21 September 2001 |
| Human-caused climate change (DECC, 2008c) | Gazetted: 17 November 2000 |
| Removal and degradation of native riparian vegetation (DPI, 2008a) | Final: 01 June 2005 |
| Installation and operation of instream structures and other mechanisms that alter the natural flow regimes of rivers and streams (DPI, 2008b) | Final: 01 June 2005 |
| Removal of large woody debris from NSW rivers and streams (DPI, 2008c) | Final: 01 June 2005 |
The impacts of these key threatening processes on riparian conditions and waterways include (DECC 2008 a, b; DPI 2008, a, b; DPI 2005a):
- bank erosion
- loss of biological diversity
- impairment of important ecosystem services for fish and invertebrates (e.g. removal of refuges used during flooding or drought or removal of spawning sites)
- reduced nutrient filtering capacity
- increased light penetration of the water-body and loss of shade and shelter for fish
- reduced inputs of organic carbon (for example, twigs and leaves)
- changes to stream behaviour (increased and decreased flow, seasonality, frequency, duration, magnitude, timing predictability, rate of rise and fall of water levels and altering surface and subsurface water levels)
- exotic plants such as Alligator weed (Alternanthera philoxeroides) reducing stream flow.
What is being done to protect riparian zones?
Information detailing what is being done to protect and enhance the riparian zones in the Gundagai Shire by community groups, Shire or other organisations, during the current reporting period, is not known.
Other nationally funded activities undertaken during the reporting period in the Murrumbidgee Catchment Management Authority area may have enhanced riparian conditions within Gundagai Shire.
References
DECC – see Department of Environment and Climate Change
Department of Environment and Climate Change (NSW) (2008a) NSW Scientific Committee—Final Determination, Alteration to the Natural Flow Regimes of Rivers, Streams, Floodplains and Wetlands—Key Threatening Process Declaration, NSW Department of Environment and Climate Change, viewed 14 October 2008, http://www.threatenedspecies.environment.nsw.gov.au/tsprofile/profile.aspx?id=20002
Department of Environment and Climate Change (NSW) (2008b) NSW Scientific Committee—Final Determination, Clearing of Native Vegetation—Key Threatening Process Declaration, NSW Department of Environment and Climate Change, viewed 14 October 2008-10-14 http://www.environment.nsw.gov.au/determinations/ClearingNativeVegKTPListing.htm
Department of Primary Industries (NSW) (2008a) Removal of large woody debris from NSW rivers and streams, NSW Department of Primary Industries, viewed 10 October 2008 http://www.dpi.nsw.gov.au/fisheries/habitat/publications/threats/removal-large-woody-debris
Department of Primary Industries (NSW) (2008b) Degradation of native riparian vegetation along NSW water courses, NSW Department of Primary Industries, viewed 10 October 2008 http://www.dpi.nsw.gov.au/fisheries/habitat/publications/threats/degredation-native-riparian-vegetation
Department of Primary Industries (NSW) (2005a) Fisheries Scientific Committee Recommendation—Installation and Operation of Instream Structures and Other Mechanisms that Alter Natural Flow Regimes of Rivers and Streams, NSW Department of Primary Industries, viewed 11 August 2005, http://www.fisheries.nsw.gov.au/__data/assets/pdf_file/5284/FR21_dams.pdf.
DPI – see Department of Primary Industries
OCE – see Office of the Commissioner of the Environment
Office of the Commissioner for the Environment (2004) Australian Capital Region State of the Environment Report 2004, Office of the Commissioner for the Environment, Canberra (see Riparian Condition)
Moore, G (2005) Director, Community Services, Gundagai Shire Council, personal communication.
Mulvaney, M, Boak, M, Priday, S, Hudson, K and Crane, M (2005) The Native Vegetation of Gundagai Shire, NSW Department of Environment and Conservation, Queanbeyan
