Severely affected by urban development and extensive erosion.
Heavily degraded riparian zone with very limited vegetation.
No in-stream vegetation.
Creek dry at time of inspection in October 2008.
Area map
About the location
Cobbler Creek rises at Golden Grove and flows through Greenwith and Salisbury East in the northeastern suburbs of Adelaide, before discharging into the Little Para River stormwater system on the Salisbury Plains. Urban development covers most of the catchment, with quarries in the upper reaches; the creek also flows through the Cobbler Creek Recreation Park for more than a kilometre. The stream is generally only wet for brief periods following winter rains, although there are some permanently wet sections in the Golden Grove area. The site selected for monitoring was located on McEvoy Drive in Salisbury East.
The creek was given a Very Poor rating at this site because the ecosystem showed evidence of major changes to both the animal and plant life, and a significant breakdown in the way the ecosystem functions because of human impact. The creek was heavily disturbed by the scale of urban development in the catchment, with fast-flowing surges of stormwater contributing to severe erosion and preventing the growth of in-stream vegetation.
Findings
The creek was dry and only two metres wide at this site when it was inspected in October 2008. The channel was deeply incised two to three metres below the banks of the creek, and more than 50% of the banks showed evidence of active erosion.
There was no evidence of surface moisture or recent algal growths among the sediments, which included both coarse cobbles and gravels, and finer clays and detritus. The sediments were not blackened or odorous, and showed no signs of any prolonged anaerobic events in recent times.
No aquatic plants were found in the creek. River Red Gums lined the channel but there were no shrubs or understorey remaining in the riparian zone, apart from introduced kikuyu grass and other weed species.
The adjacent area was urban gardens and roads.
Special environmental features
None identified.
Pressures and management responses
Pressures
Management responses
Stormwater runoff causing high water velocities, containing nutrients and sediments (causing habitat disturbance, algal growth and aquatic weeds).
The Adelaide and Mount Lofty Ranges NRM Board has a well developed stormwater quality improvement, harvesting and reuse program which has installed (and maintains) gross pollutant (and silt) traps in several watercourses across the region to catch litter, debris and silt in order to minimise impacts and damage to seagrass in the receiving marine environment. Stormwater captured is also treated through artificial wetlands across the region which act as suspended solid and nutrient filters; these wetlands also provide important habitat for many native species.
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.
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
