Chambers Creek rises at Cherry Gardens in the southern Mount Lofty Ranges, and flows west through Coromandel Valley to join the Sturt River. Livestock grazing (49%) and urban development (23%) are the major land uses in the upstream catchment, where there are also significant areas of protected native vegetation. The site selected for monitoring was located off Main Road at Coromandel Valley.
In summary
The creek was given a Fair rating at this site because the ecosystem showed evidence of moderate changes to animal and plant life, and some changes to the way the ecosystem functions. Evidence confirmed nutrient enrichment, and the limited riparian zone was contributing to large amounts of organic debris in the creek.
Findings
The creek was no more than three metres wide at the monitoring site, and comprised mostly shallow pools and small areas of flowing riffles when it was sampled in November 2008.
A diverse community of 40 macroinvertebrate species was found in the pool habitats. Most were species tolerant to poor water quality, including introduced snails (Physa acuta) and chironomids (Paramerina, Tanytarsus, Cricotopus and Dicrotendipes). The only sensitive or rare species detected were small numbers of one stonefly and one mayfly species. The riffle habitats appeared to lack species which depend on flowing water.
The water was fresh (salinity of 660 mg/L) and well oxygenated (65% saturation). It was also clear and had low to moderate levels of nutrients, such as nitrogen (0.3 mg/L) and phosphorus (0.02 mg/L).
Sediments on the creekbed were mostly made up of bedrock, gravel, detritus and silt. Some areas of sediment were blackened and anaerobic, indicating too much organic material had entered the stream.
The channel and banks showed evidence of erosion caused by high flows after heavy rainfall; pipes feed stormwater into the stream from the surrounding urban area.
Dense shading limited the growth of algae and aquatic plants. However, Common Reed (Phragmites australis), sedges (Cyperus), knotweed (Persicaria) and waterbuttons (Cotula) occurred along the creek. Exotic deciduous trees and introduced grasses dominated the narrow riparian zone, contributing to the large amounts of organic debris in the stream.
Special environmental features
Chambers Creek provides habitat for at least one notable species of stonefly (Austrocerca tasmanica) and one mayfly (juvenile from the family Leptophlebiidae), which typically occur in flowing streams with low nutrient levels in the wetter, cooler parts of the Mount Lofty Ranges.
Pressures and management responses
Pressures
Management Responses
Limited riparian zone vegetation at the site and upstream, providing minimal buffer protection from catchment landuses (reducing habitat quality).
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.
Extensive weed growth in the riparian zone at the site and upstream (causing habitat disturbance).
Large decrease in natural water flows (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.
This aquatic ecosystem condition report is based on monitoring data collected by the EPA and prepared in conjunction with the Adelaide and Mount Lofty Ranges NRM Board.
Observed Condition
Expected Condition
