Tributary of Victoria Creek, E from Williamstown
2013 Aquatic Ecosystem Condition Report
- Dry in autumn and spring 2013
- Likely to be enriched with nutrients when wet due to the surrounding land uses
- Riparian vegetation lacked any canopy species and comprised dense rushland
- Fine sediments dominate soft banks that were accessed and grazed by cattle throughout the year
About the location
Tributary of Victoria Creek is a very small first order stream in the Southern Mount Lofty Ranges that rises at an elevation of about 370 m and flows north-west for several hundred metres, before discharging into Victoria Creek near the eastern edge of Williamstown. The major land use in the 147 hectare catchment was stock grazing (47%), with smaller areas also used for native vegetation, roads, residential living and quarries. The site was located off a track to ‘Brookleigh’ from the Springton Road, about 1 km east from Williamstown.
The creek was given a Poor rating because the site sampled showed evidence of major changes in ecosystem structure and function. There was evidence of human disturbance due to cattle accessing the creekbed, lack of overstorey plants in the riparian zone and the presence of a large dam upstream that probably contributes towards the prolonged dry status of this tributary stream.
The 20 m wide shallow drainage channel was dry in both autumn and spring 2013. No macroinvertebrate or water quality data was consequently available for this site.
The sediments were dominated by detritus, with smaller amounts of clay and sand also present; samples taken from below the surface were grey silts and clays, and they showed no evidence to indicate that the sediments had recently been anaerobic or lacking in oxygen when the creek last dried (e.g. no noxious odours or signs of blackened sediments). There was also no obvious sign of any significant bank erosion at the site, despite cattle accessing and defaecating in the channel and on its poorly defined banks throughout 2013.
There was no evidence of any dried filamentous algal mats and the only aquatic plant seen at the site was a rush (Juncus) that grew over more than 35% of the creekbed. The riparian zone lacked any trees or shrubs and was defined by the presence of a dense rushland over a distance of about 5-10 m from the edge of the channel. The surrounding vegetation near the creek comprised cleared grazing land with a few scattered gums in the local landscape.
Special environmental features
Pressures and management responses
|Insufficient natural water flows in the creek resulting from water extraction and climate variability (reducing ecological integrity).||Through water allocation planning the Adelaide and Mount Lofty Ranges NRM Board seeks to manage a sustainable water supply for the region so that there is enough water available for everyone (including the environment) even in drought conditions.|
|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.|
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.