Riparian vegetation comprises native canopy species over a weedy understorey
Some evidence of bank erosion caused by flood damage
Area map
About the location
Workanda Creek is a small, first-order stream in the Southern Mount Lofty Ranges that rises near the northern part of Belair National Park, and flows initially in a westerly direction before turning south, where it eventually discharges into the Sturt River in Coromandel Valley. The monitoring site was located off the northern road, downstream from the waterfalls and 500 metres north from the main administrative buildings in the park. The major land uses in the 137 hectare catchment are conservation, with smaller areas used for roads and a railway line.
The creek was given a Good rating because the site sampled showed evidence of relatively minor changes in ecosystem structure and function. There was evidence of human disturbance including th presence of moderately eroded banks and weed invasion of the riparian zone. However, the creek lies within a national park and apart from visitors accessing the catchment via a sealed road, there are no obvious sources of further damage to this naturally occurring watercourse in the region.
Findings
The 1.5 m wide creek was dry in both autumn and spring 2011. No macroinvertebrate or water quality data was consequently available for this site.
The sediments were dominated by sand and detritus, with smaller amounts of boulder, cobble and pebble also present. Samples taken from below the surface were grey in colour and showed no evidence of being anaerobic or lacking in oxygen. A moderate amount of bank erosion was recorded over more than 10 m of the site, presumably caused by local flooding following heavy winter rainfall periods.
Only a few aquatic plants (Cyperus, Rumex and Isolepis) were noted in the channel, where they covered less than 10% of the channel. The narrow riparian vegetation comprised a range of native trees and shrubs over a weedy understorey. The surrounding vegetation at the site was remnant native vegetation.
Special environmental features
The creek provides a near natural reference stream for the region despite its obvious ephemeral hydrology.
Pressures and management responses
Pressures
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.
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Observed Condition
Expected Condition
