Tributary of Carrickalinga Creek, south from Myponga Reservoir
2011 Aquatic Ecosystem Condition Report
- Dry in autumn and spring 2011
- Likely to be enriched with nutrients when wet due to the surrounding land uses
- Riparian vegetation dominated by introduced grasses and weeds
- Minor areas of bank erosion.
About the location
Tributary of Carrickalinga Creek is a small stream in the Southern Mount Lofty Ranges that rises south from Myponga Reservoir and flows in a south-westerly direction before discharging into Wild Dog Creek, which ultimately flows into Carrickalinga Creek on the Fleurieu Peninsula. The monitoring site was located off Main South Road, about two kilometres SSW of Myponga Reservoir. The major land uses in the 327 hectare catchment are stock grazing, irrigated cropping and remnant native vegetation, with smaller areas of roads, rural residential living and perennial horticulture.
The creek was given a Poor rating because the site sampled showed evidence of major changes in ecosystem structure, and moderate changes to the way the ecosystem functions. There was considerable evidence of human disturbance including degraded riparian habitats and bank erosion.
The sediments were dominated by detritus with sand, silt and clay also present. Samples taken from below the surface were grey in colour and showed no evidence that the sediments were anaerobic or lacked oxygen. About 10 m of banks showed evidence of erosion due to recent flood damage and cattle accessing the dry channel.
No signs of any algal growths were evident among the dry sediments in the creek but about 10% of the site was covered by patches of sedges (Cyperus) and cumbungi (Typha). The narrow riparian zone consisted of a few gum trees over introduced grasses, weeds and sedges. The surrounding vegetation was cleared grazing land with only a few isolated gum trees present in the local landscape.
Special environmental features
Pressures and management responses
|Widespread introduced weeds in the riparian zone at the site and upstream (reducing habitat quality).||The Adelaide and Mount Lofty Ranges NRM Board has several pest plant (weed) mitigation and control programs. They work closely with landholders to control weeds on their property and to help stop the spread to other properties and waterways.|
|Livestock having direct access at the site and upstream (causing sediment erosion and adding excessive nutrients).||The Adelaide and Mount Lofty Ranges NRM Board’s land management program encourages and promotes managing land to improve water quality. This includes incentives for waterway and wetland fencing to exclude or limit stock from entering riparian zones.|
|Limited riparian zone vegetation at the creek and upstream (reducing habitat quality, increasing sediment erosion).||The Adelaide and Mount Lofty Ranges NRM Board’s land management program encourages and promotes managing land to improve water quality. This includes incentives for revegetation programs around waterways and wetlands and stock exclusion as well as educating landholders about the importance of riparian vegetation in managing soil erosion.|
This aquatic ecosystem condition report is based on monitoring data collected by the EPA. It was prepared with and co-funded by the Adelaide and Mount Lofty Ranges NRM Board.