Tributary of Blackfellows Creek, 1.5 km south-west from Mount Hayfield
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 consists of introduced grasses and weeds
- Moderate bank erosion caused by stock damage
About the location
Tributary of Blackfellows Creek is a small stream in the Southern Mount Lofty Ranges that rises near Mount Hayfield and the Second Valley Forest and flows for over a kilometre in a northerly direction before discharging into Blackfellows Creek. The monitoring site was located off Hayfield Road, about 1.5 km south-west from Mount Hayfield and 6 km south-east from Wirrina. The major land uses in the 15 hectare catchment are stock grazing, forestry and roads.
The creek was given a Very Poor rating because the site sampled showed evidence of major changes to both the animal and plant life inhabiting the stream, and a significant breakdown in the way the ecosystem functions. There was considerable evidence of human disturbance including severely degraded riparian habitats and bank erosion caused by cattle damage.
The sediments were dominated by detritus and clay, with silt and sand also present. Samples taken from below the surface were blackened in colour and had a strong manure odour, indicating that the sediments were anaerobic and lacked oxygen. Over 10 m of bank erosion was recorded due to the damage caused by cattle accessing the bed and banks of the creek.
Up to 65% of the channel was covered by rushes (Juncus) and the very narrow riparian zone consisted of introduced grasses and weeds. The surrounding vegetation was cleared grazing land with a few scattered gum trees remaining 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.