Permanently wet and flowing channel in autumn and spring 2016
Diverse macroinvertebrate community dominated by tolerant species but including a few sensitive and flow-dependent species
Water was moderately fresh, clear, and nutrient enriched
Riparian vegetation consisted of a few scattered gum trees and olive trees over introduced grasses, rushes and sedges
Area map
About the location
The North Para River is one of the largest streams in the Northern Mount Lofty Ranges. It rises at an elevation of about 450 m in the Flaxman Valley near Eden Valley and flows north towards Angaston, where the river flows south-east through Nuriootpa, Tanunda and Rosedale before eventually joining with the South Para River at Gawler to form the Gawler River. The major land uses in the 44,040 hectare catchment were stock grazing, irrigated vines and cropping, with smaller areas used for other minimal uses, roads, dams, residential living and mines. The site was located in the lower reaches just upstream from the weir near Chateau Yaldara Winery off Hentschke Road, about 3 km north from Lyndoch.
The river was given a Fair rating because the site sampled showed evidence of moderate changes in ecosystem structure and some changes to the way the ecosystem functions. There was evidence of human disturbance due to nutrient enrichment and the extent of weeds in the riparian zone. However, the stream also provides habitat for a few sensitive and flow-dependent macroinvertebrates.
Findings
A diverse community of at least 52 species of macroinvertebrates was collected or seen from the river (21 species in autumn and 39 in spring), 8 m wide and approximately 1 m deep in places, in autumn and spring 2016. The river consisted of deep pool habitats connected with fast-flowing riffle habitat in both seasons. The community was dominated by large numbers of amphipods (Austrochiltonia) and chironomids as well as large numbers of blackflies (Simulium ornatipes) in the riffle in spring. It also included low to moderate numbers of turbellarians, native and introduced snails (including Potamopyrgus and Physiella), mites, isopods, springtails, beetles, mosquitoes, mayflies, waterbugs, damselflies, dragonflies, stoneflies and caddisflies. Most macroinvertebrates were generalist and tolerant species that are commonly found from other organically enriched streams elsewhere in the region, however, a few more sensitive species were also identified, including the caddisfly Ulmerochorema and mayfly Thraulophlebia. A yabby claw was also found at the site in autumn.
The water was moderately fresh (salinity ranged from 1,453-2,256 mg/L), well oxygenated (72-95% saturation), clear, and with high concentrations of nutrients such as phosphorus (0.1-0.19 mg/L) and nitrogen (0.64-0.90 mg/L).
The sediments were dominated by detritus, with boulders and cobbles also present in the riffle and sand and silt dominating in the pools. Some filamentous algae was also present in spring, mainly in the riffle habitat. Samples taken from below the surface were grey silts and clays with no signs of sulfidic or anaerobic sediments. There was some evidence of bank erosion (<10%) in autumn due to sheep grazing near the banks of the creek, as evidenced by the presence of sheep droppings on the banks.
A small amount of phytoplankton was present at the site (chlorophyll a ranged from 0.82-2.36 μg/L and a filamentous alga (Cladophora) was seen in spring when it covered more than 35% of the site. Less than 35% of the site was also covered by emergent aquatic plants (Bolboschoenus, Cyperus, Eleocharis, Juncus, Phragmites and Schoenoplectus). The riparian zone comprised a few scattered gum trees and olive trees over introduced grasses, rushes and sedges. The surrounding vegetation near the creek comprised cleared sheep grazing paddocks, vineyards and a winery.
Special environmental features
The major environmental values associated with the site were the presence of the caddisfly and mayfly and a rich range of tolerant and generalist macroinvertebrate species.
Pressures and management responses
Pressures
Management responses
Nutrient inputs to the creek from numerous diffuse sources (potentially leading to excess growth of algae and aquatic weeds)
The Adelaide and Mount Lofty Ranges NRM Board land management program encourages and promotes managing land to improve water quality. This includes working with industry and landholders to ensure efficient use of fertilisers and discuss ways to reduce runoff of nutrients into waterways.
Widespread introduced weeds in the riparian zone at the site and upstream
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.
Limited riparian zone vegetation at the creek and upstream (reducing habitat quality, increasing sediment erosion)
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. The Board also partner with local government to deliver a number of watercourse revegetation projects across the region.
Saline groundwater inflows to the creek
The Adelaide and Mount Lofty Ranges NRM Board has installed telemetered groundwater monitoring stations at key locations within the region. These are monitored for level and salinity; unusual results (such as high salinity influxes) are investigated.
This aquatic ecosystem condition report is based on monitoring data collected by the EPA. It was prepared with and co-funded by the Adelaide and Mount Lofty Ranges NRM Board.
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Observed Condition
Expected Condition
