Riparian vegetation consisted of native trees and shrubs, and the edges of the waterhole included a native aquatic plant
Area map
About the location
Cooper Creek is a large stream in the Far North that rises at an altitude of 230m in western Queensland and flows south-westerly for over 1,500 km through increasingly arid woodland, grassland and desert before discharging into Lake Eyre. In the ‘channel country’ of the middle reaches it forms both deep, narrow channels which transport sand and mud at moderate flows and a large network of braided channels that transport clay-rich mud during high flow periods. As the river passes into South Australia it forms the one channel near Innamincka and then further downstream it extends across a wide floodplain and forms another mosaic of shallow freshwater and saline lakes, deep permanent and semi-permanent channel reaches, flooded woodlands and grasslands, samphire-lined claypans and other wetlands (for more details see Walker et al. 1997 and Silcock 2009). Flow patterns in the unregulated Cooper Creek are highly variable and driven by monsoonal summer rainfall in the upper catchment area in Queensland. Most water is retained or evaporates in the channel country and only 30% of overbank flows reaches Innamincka. As a result, Lake Eyre only receives water during extremely large floods.
The major land uses in the 296,000 square kilometre catchment are sheep (Qld only) and cattle grazing on native grasslands, with smaller areas used for rural towns and settlements, mining, tourism and national parks.
The monitoring site was located in the Innamincka Regional Reserve off the Nappa Merrie Road on Cooper Creek, about 13 kilometres east from Innamincka.
The creek was given a Good rating because the site sampled showed evidence of relatively minor changes in ecosystem structure and function. There was evidence of human disturbance due to nutrient enrichment effects but the stream provides habitat for a range of aquatic species, including at least four rare and sensitive species of macroinvertebrates. Note that the high nutrient concentrations recorded from the waterhole were similar to other sites sampled from Cooper Creek and were assumed to have originated from upstream grazing and cropping practices. Similarly, the high turbidity was sourced by floods naturally mobilising clays from the channel country in Queensland and was not obviously exacerbated by local land use practices.
Findings
A moderately diverse community of at least 15 species of macroinvertebrates was collected from the 100 m wide, non-flowing, arid-zone waterhole in spring 2012. The community was dominated by moderate numbers of chironomids (Dictrotendipes), baetid mayflies (Cloeon) and freshwater prawns (Macrobrachium) and included low numbers of 4 species of beetles, 2 waterbugs, 2 molluscs (snail Centrapala and bivalve Corbiculina), two caddisflies (Triplectides australis and Triplectides volda), one type of biting midge and a single damselfly nymph. The community included groups normally associated with stream environments (prawns and molluscs) and others that are typically found in pool habitats and temporary waters throughout the Far North region (e.g. insects such as beetles, bugs, flies and caddisflies). The mayfly represents a sensitive species with a widespread distribution from the more permanent freshwater habitats in the eastern Lake Eyre Basin. The two molluscs and T. volda are rarely collected in the region and are probably indicator species for the maintenance of suitable permanent waterholes on the Cooper Creek system. A single carp gudgeon (Hypseleotris) was the only fish caught at the site.
The water was fresh (salinity of about 143 mg/L), well oxygenated (115% saturated) and turbid (secchi depth 8 cm), with high concentrations of nutrients such as nitrogen (2.81 mg/L) and phosphorus (0.53 mg/L).
The sediments were dominated by living and dead detritus, with smaller amounts of sand, clay and silt; samples taken from below the surface were grey clays and silts and sulfidic, indicating that the sediments were occasionally anaerobic, or lacking in oxygen. No evidence of any significant bank erosion was noted.
A large amount of phytoplankton was present (chlorophyll a 12 µg/L) which included a small amount of cyanobacteria or blue-green algae (chlorophyll b 0.8 µg/L) but no filamentous algae was observed. Over 35% of the edge of the waterhole was covered by Water Primrose (Ludwigia peploides). The riparian vegetation was dominated by gum trees over lignum and acacias, with patches of spiny sedge (Cyperus gymnocaulos) and paperbark trees in places on the well vegetated banks (between 50-79% vegetative cover). The surrounding vegetation comprised low gum and acacia woodland that extended a few hundred metres away from the waterhole.
Special environmental features
Cullyamurra Waterhole was sampled for fish using a range of nets in November 2011 and again in April 2012, as part of the Lake Eyre Basin Rivers Assessment (Cockayne et al. 2013). The waterhole provides an important permanent refuge habitat for at least 8 native species (Desert Glassfish, Bony Bream, Desert Rainbowfish, Welch’s Grunter, Carp Gudgeon, Spangled Perch, Lake Eyre Golden Perch and Hyrtl’s Catfish) but also supports low numbers of two introduced pest species (Mosquitofish and Goldfish).
Pressures and management responses
Pressures
Management responses
High nutrient concentrations causing excessive algal growth although the source(s) of the nutrients are not known.
The EPA in collaboration with the Department for Environment, Water and Natural Resources is anticipating a study program to investigate the source(s) of nitrogen and phosphorus. This will provide a better understanding of nutrient dynamics with the aim of developing a management strategy (if appropriate).
Cockayne, B., Schmarr, D., Duguid, A. & R. Mathwin (2013). “Lake Eyre Basin Rivers Assessment (LEBRA) 2012 Monitoring Report.” Report to LEBRA Oversight Group.
Silcock, J. (2009). “Identification of Permanent Refuge Waterbodies in the Cooper Creek and Georgina-Diamantina River Catchments for Queensland and South Australia.” Final report to South Australia Arid Lands Natural Resource Management Board.
Walker, K.F., Puckridge, J.T. & S.J. Blanch (1997). Irrigation development on Cooper Creek, central Australia – prospects for a regulated economy in a boom-and-bust ecology. Aquatic Conservation: Marine and Freshwater EcosystemsVolume 7, pages 63-73.
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Observed Condition
Expected Condition
