Bungala Creek, East of Yankalilla
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 consisted of gums over rushes and introduced grasses
- No evidence of significant bank erosion despite horses regularly accessing the creek
About the location
Tributary of Bungala River is a small first-order creek that rises at an elevation of about 160 m and flows south-west, where it joins with other tributaries to form Bungala River. This stream then flows west through the townships of Yankalilla and Normanville, where it ultimately discharges into Gulf St Vincent. Major land uses in the 57 hectare catchment upstream from the site were stock grazing (59%) and cropping (14%), with minor areas used for other minimal uses, plantation forestry, roads, irrigated horticulture and rural housing. The site was located upstream from Kemmiss Hill Road at the headwaters of Bungala River, about 2.5 km east from Yankalilla.
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 the extent of riparian disturbance and lack of remnant native vegetation in the wider catchment.
The 2-2.5 m wide 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, silt and sand also present; samples taken from below the surface were grey sands, silts and clays that showed no evidence to indicate that the sediments had recently been anaerobic or lacking in oxygen. There was no evidence of any significant bank erosion recorded during either site inspection but the presence of horse droppings in the channel, indicates that occasional damage to the banks may occur whenever they are wet and soft.
Less than 10% of the channel was covered by patches of aquatic plants (Juncus and Rumex); there was no evidence of any dried filamentous algal mats on the dry sediments of the creek. The presence of introduced terrestrial grasses within the channel suggests that this tributary probably rarely holds water for more than a few weeks or months of the year; prolonged dry periods typically enables the surrounding terrestrial grasses and weeds from adjacent agricultural lands to invade the channels of ephemeral streams anywhere in the State. The riparian zone on each bank was limited to a single line of River Red Gums over rushes, dock, introduced grasses and bridle creeper. The surrounding vegetation near the creek comprised horse grazing pasture with a few scattered gums and an olive grove further downstream.
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.|
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.