Waitpinga Creek is a small coastal stream on the Fleurieu Peninsula, which rises southwest of Victor Harbor and flows south through land used mainly for livestock grazing (54%), dairying (28%) and horticulture (12%) before discharging into the Southern Ocean at Waitpinga Beach.
The site selected for monitoring was located off Waitpinga Road, about 10 km southwest of Victor Harbor.
The creek was given a Fair rating at this site because the ecosystem showed moderate changes to animal and plant life, and some changes to the way the ecosystem functions. Human activity has led to excessive nutrient levels and associated high algal growths, and large amounts of fine sediment; it has also damaged the riparian zone.
Findings
At the time of monitoring in December 2008, the creek was less than 1 cm deep. It trickled slowly through dense stands of emergent water plants such as Cumbungi (Typha domingensis), Waterbuttons (Cotula coronopifolia), and the introduced herb, Watercress (Rorippanasturtium-aquaticum). Due to low flows in the creek, macroinvertebrates were not assessed on this occasion.
Green filamentous algae covered up to 65% of the channel which contained so little water that it was impossible to take samples and assess concentrations of salinity, oxygen, nitrogen and phosphorus.
Sediments in the creek were mostly anaerobic, blackened silt with patches of clay.
River Red Gums grew over tea-tree (Leptospermum) in a very limited riparian zone, with the understorey and groundcover dominated by introduced grasses and woody weeds such as kikuyu, gorse and boxthorn. Riparian cover only extended for one tree width along the creekline. Cattle grazed on cereal stubble in the surrounding area at the time of monitoring.
Special environmental features
The most significant feature of this creek was the presence of tea-tree shrubland in the riparian zone.
Pressures and management responses
Pressures
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 Adelaide and Mount Lofty Ranges NRM Board's land management program encourages and promotes managing land to improve water quality. This includes incentives for waterway and wetland fencing to exclude or limit stock from entering riparian zones.
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 (reducing habitat quality).
The Adelaide and Mount Lofty Ranges NRM Board has several pest plant (weed) mitigation and control programs. They work closely with landholders to control weeds on their property and to help stop the spread to other properties and waterways.
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
