Biological Survey of receiving waters for proposed wastewater discharge, Iris River

This document reports on an assessment of the aquatic biological values of the upper Iris River, and the implications and risks associated with a proposal to discharge treated wastewater from the Cradle Valley area. A review of existing data and literature for the area was conducted, followed by a field survey of aquatic macroinvertebrates, plants and fish. The survey was conducted at three sites in the Iris River at and downstream of the proposed discharge location, one 'reference' site upstream in the Iris, and two 'reference' sites in the adjacent Fall River. The biological data was reviewed to assess: - the presence of any threatened species listed under the Tasmanian Threatened Species Protection Act (TSPA, 1995) and/or the Environmental Protection and Biodiversity Conservation Act (EPBCA, 1999); - the presence of any special biological values or biodiversity issues; - the ecological condition of the stream sites; - the presence of any other impacts or threatening processes. The field data was also collected in such a manner as to provide a dataset as a basis for future monitoring. Thus, both qualitative and quantitative sampling methods were used. An overall assessment of conservation status of the Iris River downstream of the proposed discharge point was conducted using three criteria identified by Dunn (2000) and now used within the development of DPIWE's framework for conservation of freshwater ecosystem values (CFEV). These criteria are: - naturalness - distinctiveness - representativeness. These criteria were used to assess the aquatic biological data and identify any risks to the aquatic environment that may result from the proposed discharge