Salt Creek, near Lipson
2010 Aquatic Ecosystem Condition Report
- Shallow, ephemeral creek that was wet in autumn but had surface water that was too shallow and limited to sample in spring.
- Very sparse macroinvertebrate community with no rare or sensitive species.
- High salinity probably responsible for the limited plant responses to obvious nutrient enrichment of the stream.
- Riparian vegetation limited to weeds and samphire.
- Some bank erosion and silt deposits in the channel.
About the location
Salt Creek near Lipson is a large stream in Eyre Peninsula. However, unlike the much larger Salt Creek that is located north of Cleve, this stream rises north of Uranno, flows north and then east before eventually discharging into Spencer Gulf at Salt Creek Beach in Tumby Bay. The major land uses are sheep grazing and cropping, with minor areas of native vegetation in the upper reaches.
The monitoring site was located at the Muntoburrowie ford in the lower reaches of the creek off Lipson Cove Road, about six kilometres north-east of Lipson and 15 kilometres north-east of Tumby Bay.
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 because of the very high salinity levels and lack of vegetation in the riparian zone and catchment.
A very low diversity of about six species of macroinvertebrates was collected from the creek, four metres wide and four centimetres deep, in autumn 2010; the site was drying out in spring and only had a puddle present that was too small to sample. The community was dominated by species tolerant to high salinity and poor water quality, including a beetle (Necterosoma penicillatus), two chironomids (Procladius and Tanytarsus) and a salt-lake snail (Coxiella). It also included smaller numbers of a lestid damselfly and an unidentified caddisfly. No sensitive or rare species were found.
The water was saline (salinity of 23,732 mg/L), well oxygenated (137% saturation), slightly turbid and coloured, with moderate to high concentrations of nutrients such as nitrogen (1.5 mg/L) and phosphorus (0.04 mg/L).
The sediments were dominated by clay, sand, detritus and algae; samples taken from below the surface were sandy grey in colour and not obviously anaerobic. A deposit of 1–5 centimetres of silt covered the creekbed and some bank erosion was noted due to past flood damage.
A moderate growth of phytoplankton was present and filamentous algae (Cladophora) covered about 10% of the site. The only aquatic plants growing in the creek were a few specimens of submerged Sea Tassel (Ruppia).
The riparian zone was very limited and included samphire and weeds. The surrounding vegetation at the site lacked native species and consisted of cropping land and grazed grassland.
Special environmental features
Pressures and management responses
|Livestock have direct access at the site and upstream in the catchment, causing sediment erosion and adding excessive nutrients (which leads to habitat disturbance, algal growth and aquatic weeds).||
The Eyre Peninsula NRM Board promotes managing land to improve water quality. This includes incentives for:
|Limited natural riparian vegetation at the site and upstream in the catchment, providing minimal buffer protection from catchment landuses (reducing habitat quality).|
|Saline groundwater inflow (reducing ecological integrity).||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.|