Oraparinna Creek, Dingley Dell
2012 Aquatic Ecosystem Condition Report
- Dry in autumn and spring 2012
- Unlikely to be nutrient enriched when wet because the catchment is in a national park
- No bank erosion or evidence of feral animals either accessing or damaging the site
- Riparian vegetation consisted of native trees and shrubs
About the location
Oraparinna Creek is a small intermittent stream in the Flinders Ranges National Park that rises north of Linkes Mine and flows in a north-westerly direction, where it joins with Enorama Creek and eventually discharges into Brachina Creek to the east of the ABC Range. This stream then discharges onto the plains surrounding the eastern side of Lake Torrens. The only land use in the 1,549 hectare catchment, upstream from the site, is national park. The monitoring site was located off an unsealed track from the Blinman to Wilpena Road, about 2 km north-west from Oraparinna and 21 km north from Wilpena.
The creek was given a Very Good rating because the site sampled showed evidence of very little changes in ecosystem structure and function, with no obvious evidence of any significant human disturbance based on the data collected from the dry site in 2012.
The sediments were dominated by sand, gravel, boulder and pebble, with smaller amounts of bedrock, cobble, silt and detritus also present. Samples taken from below the surface were grey sands and red clays, and showed no signs that the sediments were recently anaerobic, or lacking in oxygen. No evidence of any bank erosion was recorded and the only sign of animals accessing the banks was from the deposit of kangaroo faeces at the site.
Only one type of aquatic plant (sedge Cyperus gymnocaulos) was recorded but there was no evidence of any algal remnants among the dry sediments in the channel. The riparian vegetation was dominated by River Red Gums and acacias over sedges and native shrubs on the moderately well vegetated banks (50-79%% vegetative cover). The surrounding vegetation at the site comprised low native woodland dominated by White Cypress Pine (Callitris), wattles and a range of native shrubs.
Special environmental features
Oraparinna Creek is a largely natural, ephemeral stream that lies in the middle of the Flinders Ranges National Park. Prior to its incorporation into a national park in 1970, the Oraparinna Station was grazed by sheep and cattle for over 100 years. The damage caused to the vegetation associations in the area and subsequent changes with the removal of grazing pressure are documented in the management plan for the park. No significant environmental values were recorded from the dry site in 2012. However, a wide range of insects, mites and molluscs were recorded from the same location in 1994-95 when pools and flowing riffle habitats were present. The site supported several sensitive and rarely collected species from the region (e.g. baetid mayfly Offadens, caddisfly Orphninotrichia and small unidentified stoneflies), so the creek can support an important aquatic fauna when it is wet.
Pressures and management responses
|Feral goats in the catchment are exerting excessive grazing pressure on vegetation, causing erosion and adding excessive nutrients to the watercourse.||The SA Arid Lands Natural Resources Management Board provides technical advice and incentives for the management of introduced weeds and feral pest animals, as funding permits. Pest management efforts are guided by a region-wide strategy, based on risk assessment, to determine priority locations and species. Funding is actively sought from a number of sources to support region-wide integrated management.|