Riparian vegetation limited and consisting of native shrubs and sedges over introduced grasses and weeds.
Large deposit of fine silt in the channel.
Area map
About the location
Stinky Creek is a small coastal stream in Eyre Peninsula that rises about three kilometres inland from the coast and drains into Spencer Gulf at Boston Bay. The major land uses are cropping, native vegetation and rural housing.
The monitoring site was located off the Lincoln Highway, about six kilometres north of Port Lincoln.
The creek was given a Very Poor rating because the site sampled showed the ecosystem was in a severely degraded condition with major changes to both the animal and plant life, and a significant breakdown in the way the ecosystem functions. There was considerable evidence of human disturbance including nutrient enrichment, silt deposition and poor riparian habitat.
Findings
A very sparse community of only five species of macroinvertebrates was collected from this creek in autumn and spring 2010. The creek consisted of a series of isolated pools in autumn and a slow-flowing channel that extended over seven metres wide and up to 14 centimetres deep in spring.
The community was dominated by species tolerant to high salinity and poor water quality, such as mosquitoes (Aedes) and amphipods (Austrochiltonia australis) in autumn; only one worm and one rove beetle were collected. In spring, only one dragonfly nymph was recorded from the site along with large numbers of zooplankton (ostracods). No sensitive or rare species were found.
The water was saline (salinity of 10,421 mg/L in autumn and 7,441 mg/L in spring), moderately well to well oxygenated (44–137% saturation) and clear, with moderate to high concentrations of nutrients such as nitrogen (1.08–4.44 mg/L) and phosphorus (0.02–0.08 mg/L).
The sediments were dominated by detritus, silt, cobbles and boulders; samples taken from below the surface were anaerobic and lacking in oxygen. A deposit of 5–10 centimetres of silt covered the creekbed upstream of the culvert that passes under the highway. The creek widens and deepens just downstream due to the effects of the culvert concentrating flows past the road’s infrastructure.
Small amounts of phytoplankton were recorded from the creek during autumn and spring but no filamentous algae was observed in 2010. There were no aquatic plants growing in the channel, however sedges (Cyperus) and rushes (Juncus) were growing on the banks.
The narrow riparian zone consisted of acacias and paperbarks over a groundcover of introduced grasses and weeds. The surrounding vegetation consisted of rural residential properties, patches of native vegetation and cropping land.
Special environmental features
None detected.
Pressures and management responses
Pressures
Management responses
Limited natural riparian vegetation at the site and upstream in the catchment, providing minimal buffer protection from catchment landuses (reducing habitat quality).
The Eyre Peninsula NRM Board 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.
The Eyre Peninsula NRM Board promotes the revegetation of recharge areas known to contribute to dryland salinity and encourages the adoption of perennial pastures as an alternative to annual cropping in these areas.
Observed Condition
Expected Condition
