Fish communities of Gulungul Creek - a landscape analysis. Phase 1: 'First-pass' analyses of 1979-2001 late-wet-early-dry season data, October 2001

2003

Internal Report 405
Bishop KA & Walden DJ
Supervising Scientist Division
Department of the Environment, Water, Heritage and the Arts

About the report

Gulungul Creek flows past the western lease boundary of the Ranger uranium mine. There are two primary scenarios by which aquatic biota within the creek are potentially exposed to contaminants arising from the mine:

Scenario 1: The creek flows close to Ranger’s tailings dam, therefore disturbances on aquatic communities located downstream of the dam may occur if substantial quantities of mine contaminants seeped from the dam and into the creek via groundwater.

Scenario 2: In the case of fish communities, during the wet season there is both (i) extensive movement of many fish species along Gulungul Creek and between Gulungul and Magela creeks, as well as (ii) recruitment of some fish species from the lower reaches of Gulungul Creek (including Gulungul Billabong located at the confluence of the Gulungul and Magela creeks), and from the adjacent Magela Creek, to the upper reaches of Gulungul Creek. Thus, contamination of Magela Creek and Gulungul Billabong (via backflow from Magela Creek) from mine wastes could be indirectly transferred to the middle and upper reaches of Gulungul Creek.

eriss is in a strong position to assess whether or not there are mine-disturbance signals on biotic communities of the creek, given their extensive landscape-scale data on fish communities of the creek, spanning the period 1978 to 1990. To facilitate such an assessment, eriss initiated an investigation in early 2001 that involved the collection of a current-condition fish community sample from the creek (Late-wet–Early-dry season focus), and an analysis of the gathered data in conjunction with the 1978–90 data.

In a first-pass context, the present report aims to initially determine whether there are any obvious Scenario-1 mine-disturbance signals, and less specifically, any downstream-focused non-specific disturbance signals which may be a mixed response to a range of disturbances (ie natural processes, Scenario-2 mine disturbances, and a range of other anthropogenic disturbances).