Cairns Regional Council Water and Waste Report for Mulgrave River Aquifer Feasibility Study Flora and Fauna Report November 2009 Contents 1. Introduction 1 1.1 Background 1 1.2 Scope 1 1.3 Project Study Area 2 2. Methodology 4 2.1 Background and Approach 4 2.2 Demarcation of the Aquifer Study Area 4 2.3 Field Investigation of Proposed Bore Hole Sites 5 2.4 Overview of Ecological Values Descriptions 5 2.5 PER Guidelines 5 2.6 Desktop and Database Assessments 7 3. Database Searches and Survey Results 11 3.1 Information Sources 11 3.2 Species of National Environmental Significance 11 3.3 Queensland Species of Conservation Significance 18 3.4 Pest Species 22 3.5 Vegetation Communities 24 3.6 Regional Ecosystem Types and Integrity 28 3.7 Aquatic Values 31 3.8 World Heritage Values 53 3.9 Results of Field Investigation of Proposed Bore Hole Sites 54 4. References 61 Table Index Table 1: Summary of NES Matters Protected under Part 3 of the EPBC Act 5 Table 2 Summary of World Heritage Values within/adjacent Aquifer Area of Influence 6 Table 3: Species of NES Identified as Occurring within the Study Area 11 Table 4: Summary of Regional Ecosystems and Groundwater Dependencies 26 42/15610/100421 Mulgrave River Aquifer Feasibility Study Flora and Fauna Report Table 5: Freshwater Fish Species in the Mulgrave River 36 Table 6: Estuarine Fish Species in the Mulgrave River 50 Table 7: Description of potential borehole field in Aloomba as of 20th August, 2009. 55 Figure Index Figure 1: Regional Ecosystem Conservation Status and Protected Species Observation 21 Figure 2: Vegetation Communities and Groundwater Dependencies 30 Figure 3: Locations of Study Sites 54 Appendices A Database Searches 42/15610/100421 Mulgrave River Aquifer Feasibility Study Flora and Fauna Report 1. Introduction 1.1 Background As part of the conclusion of its Water Supply Strategy, Cairns Regional Council Water and Waste is embarking on a program of works to provide necessary information to confirm its future water supply source. The assessment of the abstraction feasibility of a water supply from the Mulgrave River Aquifer (Mulgrave River Aquifer Scheme) forms part of this program of works. The proposed works includes the construction and operation of a borefield within an area of alluvium comprising part of the Mulgrave River aquifer. The borefield is designed to abstract up to 15 ML/day from up to ten bores, located in a general area between the Bruce Highway and the Mulgrave River, south of the small township of Aloomba, 20 km south of Cairns (see Figure 1 for Study Area). Each bore will have an electric submersible pump, and a connecting powerline, and be connected in an underground pipe network alongside the existing rural roads in the area and ultimately connect into the existing Behana Ceek water supply pipeline adjacent the project area. The only visible expression of the bores will be small security housing over each bore (approximately 2m by 3m) with a connecting powerline from the existing power grid. The borefield is designed as a supplementary water supply only for the southern Cairns area. It will be operated on an “as needs” requirement, only when other existing water supplies reach their allocated limits. Cairns Regional Council Water and Waste (CRCWW) currently hold a Licence to Take Water from the Mulgrave River Alluvium for up to 15,000 ML/year (approximately 40 ML/day) under certain land identified on the licence. This current proposed action is to abstract up to a maximum of 5,500 ML/year (or approximately 15 ML/day). Potential impacts arise from two aspects of this proposal: Short-term impacts arising from construction of the borefield, water treatment plant, reservoir and associated pipeline infrastructure; and Long-term impacts on the aquifer and associated ground water levels and consequential impacts on environmental values as well as possible socio-economic impacts and landuse impacts. 1.2 Scope The Mulgrave River Aquifer Scheme was referred to the Commonwealth in 2005 under the provisions of Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). A Public Environment Report (PER) has been requested by the Commonwealth in order to determine the impact of the project on matters of National Environmental Significance (NES) that may be impacted upon by the project. The full legislative background to the referral and subsequent Commonwealth request for further information is outlined in Section 2.4. Specifically, the PER has been requested to address under the Terms of Reference the following matters of NES: Southern Cassowary (Casurarius casuarius johnsonii) (LE), including regional status, population size and distribution within the project site and adjacent habitat that may be impacted by the project. 42/15610/100421 Mulgrave River Aquifer Feasibility Study 1 Flora and Fauna Report Waterfall Frog (Litoria nannotis) (LE) and Common Mistfrog (Litoria rheocola) (LE), including regional status, population size and distribution within the project site and adjacent habitat that may be impacted by the project. Red Goshawk (Erythrotriorchis radiatus) (LV) and the Australian Painted Snipe (Rostratula australis) (LV, also listed migratory), including regional status, population size and distribution within the project site and adjacent habitat that may be impacted by the project. Flora species, Dendrobium Orchid (Dendrobium mirbelianum) (LE), Dendrobium nindii (LE), Eleocharis retroflexa (LV), Water Tassel-fern (Huperzia phlegmarioides) (LV). Listed migratory bird species that could occur in the project area, including regional status, population size, distribution and the habitat that may be impacted by the project. The purpose of this report is to summarise the methods and outcomes of the surveys undertaken in support of the PER. 1.3 Project Study Area The Project Study Area comprises part of the catchment of the Mulgrave River itself, and part of that area of the Mulgrave River valley underlain by Quaternary alluvium, referred to as the Mulgrave River aquifer. The Mulgrave River catchment includes only a small proportion of the Mulgrave River aquifer, however information related to catchment conditions, particularly as they relate to climate and surface and ground water features, were used in developing the numerical ground water model upon which many of the assessments of impacts in this report are made. Potential impacts of the project will be restricted to the environs of the Mulgrave River aquifer system, which comprises less than ¼ of the area of the total river catchment area. For the purposes of this PER, the Study Area is defined as areas of the Trinity Inlet catchment and the lower Mulgrave River valley below 20 m AHD and bounded (approximately) by points at: 17° 14’ S, 145° 57’ E; 17° 14’ S; 145° 55’ E, 17° 02’ S, 145° 45’ E; and 17° 02’ S, 145° 50’ E. Both the location of the catchment and the aquifer area are described below in further detail and the Study Area for the PER is shown in Figure 1. The Study Area for the PER was refined by the initial outcomes of the predicted numerical groundwater model (as described in Section 3). The Study Area does not include the entire catchment, as significant areas of the catchment are not influenced by the aquifer system. 1.3.1 The Mulgrave River Catchment Area The Mulgrave River catchment is located within the Wet Tropics of North Queensland, south of the regional centre of Cairns. Covering an area of approximately 810 km2 and with a mean annual discharge of 770,000 ML, the catchment has one of the highest areas of mean annual runoff of any Australian catchment. It receives high to very high annual rainfall, and takes in drainage sections of the Atherton 42/15610/100421 Mulgrave River Aquifer Feasibility Study 2 Flora and Fauna Report Tablelands on its western boundary and a number of coastal tributaries including the major streams of Behana Creek and Little Mulgrave River. Although most of the coastal plain has been developed for agriculture, with sugar cane production the most significant agricultural activity, the majority of the catchment is relatively pristine rugged mountain range, with more than 50% of the total area lying within the Wet Tropics of Queensland World Heritage Area (WTQWHA). 42/15610/100421 Mulgrave River Aquifer Feasibility Study 3 Flora and Fauna Report 2. Methodology 2.1 Background and Approach The PER is framed around the guidelines provided by the Commonwealth (Appendix A), and includes both the specific matters identified in the Guidelines as well as assessing other matters of conservation significance in the Study Area. Data for the assessment was sourced from multiple sources, and includes; Initial data from background research, including public databases, published information and data provided by individual contributors. Field Studies undertaken in support of the findings from the above background data research. Data sources from studies undertaken specifically for the Cairns Regional Council as part of the Mulgrave River Aquifer Feasibility Studies. This primarily includes data derived from two separate investigations for these Studies, namely a Numerical Groundwater Modelling Report and a Hydrogeological Report; both of these reports are produced in Appendices D and E respectively. The key area of investigation was the interaction of the ground water abstraction with the surface water flows in the Study Area (notably that of Mulgrave and Behana Creek as the major waterways, but also considering other minor watercourses). Of particular importance was the assessment of the potential impact of a lessened water flow on the identified ecological values of the Study Area as a result of abstraction. 2.2 Demarcation of the Aquifer Study Area The Study Area for the PER has been defined following hydrogeological investigations, the initial outcomes of the Numerical Groundwater Modelling Report and the requirements of the Commonwealth PER Guidelines.