Harrison Creek, near Kitticoola Mine
2010 Aquatic Ecosystem Condition Report
- Dry in autumn and slow-flowing, freshwater channel in spring.
- Sparse macroinvertebrate community with no rare or sensitive species.
- Obvious signs of moderate nutrient enrichment.
- Riparian vegetation was mostly River Red Gums and introduced grasses.
About the location
Harrison Creek is a moderate sized stream in the eastern Mount Lofty Ranges, rising east of Mount Pleasant and draining southwards where it ultimately discharges into Reedy Creek. The major land use is sheep grazing with minor areas of native vegetation. The monitoring site was located on a track off Camels Hump Road, over two kilometres south of Palmer.
The creek was given a Fair rating because the site sampled showed moderate changes in ecosystem structure and some changes to the way the ecosystem functions. There was evidence of human disturbance, including nutrient enrichment and degraded riparian habitat.
A sparse community of about 16 species of macroinvertebrates was collected from the slow-flowing creek, five metres wide and up to 30 cm deep, in spring 2010; the site was dry in autumn. The community was dominated by species tolerant to poor water quality and brackish salinities such as dytiscid beetles and chironomids (including Tanytarsus and Chironomus). It also included planorbid snails, amphipods, beetles (Necterosoma, gyrinids, hydrophilids and scirtids), baetid mayflies, corixid and notonectid waterbugs, damselflies and caddisflies. However, no sensitive or rare species were found.
The water was moderately fresh (salinity of 1,665 mg/L), well oxygenated (81% saturation) and slightly coloured, with moderate to high concentrations of nutrients such as nitrogen (1.73 mg/L) and phosphorus (0.06 mg/L).
The sediments were dominated by boulders, cobbles, gravel, sand and detritus; samples taken from below the surface showed no evidence that the sediments were lacking oxygen. A small amount of silt was evident in parts of the channel and less than 10 metres of bank showed evidence of erosion due to stock and flood damage in the past. A small amount of phytoplankton was recorded and over 10% of the site was covered by filamentous algae (Cladophora) in spring.
Aquatic plants also covered over 10% of the channel, and included a range of emergent species (Cyperus, Juncus, Phragmites and Typha). The narrow riparian zone consisted of River Red Gums over introduced grasses and reeds (Phragmites). The surrounding vegetation was scattered gums, melaleucas and acacias over introduced grasses and weeds.
Special environmental features
Pressures and management responses
|Livestock have direct access at the site and upstream, causing sediment erosion and adding excessive nutrients (which leads to habitat disturbance, algal growth and aquatic weeds).
|The SA Murray–Darling Basin NRM Board acknowledges the significant impacts that livestock have on aquatic environments and seeks to provide free technical advice and incentives to land managers for fencing and other works as funding permits. Funding incentives are limited in value and extent and require land managers to volunteer to be involved.
|Limited riparian vegetation at the site and upstream, providing minimal buffer protection from catchment landuses (reducing habitat quality).
|The SA Murray–Darling Basin NRM Board recognises that the management of riparian vegetation requires a long-term, integrated approach to achieve ecosystem benefits. The board therefore provides free technical advice on a range of topics for land managers and various incentives for works as funding permits.