Cairns Regional Council Water and Waste Mulgrave River Aquifer Feasibility Study Public Environment Report

November 2009 Contents

Executive Summary i

Abbreviations ix

Glossary of Terms x

1. Introduction 1 1.1 Background 1 1.2 Objectives and Scope 1 1.3 Background to the Development of the Action 4 1.4 Relationship of the Action to Other Actions that May be Affected 5 1.5 Current Status of the Action 5 1.6 Consequence of the Action Not Proceeding 5

2. Description of the Action 7 2.1 Location 7 2.2 Detailed Proposal 10 2.3 Additional Licences / Permits and Approval Requirements required by the Project 15

3. Methodologies 23 3.1 Background and Approach 23 3.2 Demarcation of the Aquifer study area 23 3.3 Overview of Ecological Values Descriptions 26 3.4 PER Guidelines 26 3.5 Desktop and Database Assessments 27 3.6 Environmental Flows Assessment 30 3.7 Bore Testing and Modelling Verification 31 3.8 Derivation of Risk Assessment Methodologies 34 3.9 Stakeholder and Community Engagement 37

4. Description of the Environment – Physical Aspects 40 4.1 Information Sources 40 4.2 Climate 40 4.3 Topography 41 4.4 Surface Drainage Features 43 4.5 Soils 43

42/15610/99537 Mulgrave River Aquifer Feasibility Study Public Environment Report 4.6 Geology 48 4.7 Hydrogeology 51 4.8 Groundwater 53 4.9 Social Environment 54

5. Description of the Environment – Ecological 57 5.1 Information Sources 57 5.2 Species of National Environmental Significance 57 5.3 Queensland Species of Conservation Significance 65 5.4 Pest Species 68 5.5 Vegetation Communities 70 5.6 Regional Ecosystem Types and Integrity 73 5.7 Aquatic Values 76 5.8 World Heritage and National Heritage Values 95

6. Construction Phase Impacts 97 6.1 Background 97 6.2 Borefield Development Impacts 97 6.3 Social and Planning Construction Phase Impacts 98 6.4 Risk Assessment Matrices 99

7. Operational Phase Impacts 101 7.1 Background 101 7.2 River Processes and Interactions 101 7.3 Cultural/Social Assessment 109 7.4 Habitat Integrity and Availability 112 7.5 Environmental Flows 113 7.6 Flora of Conservation Significance 116 7.7 Fauna of Conservation Significance 119 7.8 Invasive Fauna and Flora Species 123 7.9 Climate Change 127 7.10 Risk Assessment Matrices 127

8. Prudent and Feasible Alternatives 139 8.1 Introduction 139 8.2 Comparative Impacts between Barron River (Lake Placid) Option and Mulgrave River Aquifer Scheme 140 8.3 Environmental Cost Benefit Comparison 152 8.4 “Do Nothing Option” 155

42/15610/99537 Mulgrave River Aquifer Feasibility Study Public Environment Report 9. Proposed Safeguards and Mitigation Measures 156 9.1 Environmental Management Plan 156 9.2 Environmental Triggers and Thresholds for Actions 158

10. Conclusions and Recommendations 162 10.1 Summary of Impacts 162 10.2 Justification for Proposed Action 162 10.3 Compliance with Principles of Ecologically Sustainable Development 163 10.4 Matters of National Environmental Significance 163 10.5 Environmental Acceptability 164 10.6 Technical Feasibility 164 10.7 Compliance with the Objectives of the Environment Protection and Biodiversity Conservation Act 1999 164

11. References 166

Table Index Table 1: Proposed Mitigation Measures for the Mulgrave River Aquifer Scheme vii Table 2 Summary of the Potential Impacts in Relation to Different Climatic Scenarios viii Table 3: Legislative Assessment Requirements 19 Table 4: Summary of NES Matters Protected under Part 3 of the EPBC Act 26 Table 5: Summary of World Heritage Values within/adjacent Aquifer Area of Influence 27 Table 6: Threat Criteria and Consequent Scales 35 Table 7: Likelihood Rating 36 Table 8: Risk Levels and Management Action (example) 37 Table 9: Details of Stakeholders Consulted 38 Table 10: Soil Type and Vertical Conductivity (from DNR, 1999) 44 Table 11: CSIRO Description of Soils in the study area 45 Table 12: Stratigraphic Units (after Muller 1975) 49 Table 13: Major Hydrogeological Units 51 Table 14 Population projections, medium growth – Population and Housing Fact Sheet – August 2009 – Department of Infrastructure and planning 54

42/15610/99537 Mulgrave River Aquifer Feasibility Study Public Environment Report Table 15: Tenure/Landuse in Proposed Infrastructure Areas 56 Table 16: Species of NES Identified as Occurring within the study area 58 Table 17: Summary of Regional Ecosystems and Groundwater Dependencies 71 Table 18: Freshwater Fish Species in the Mulgrave River 81 Table 19: Estuarine Fish Species in the Mulgrave River 92 Table 20: CRCWW, Summary Construction Risk Assessment, Mulgrave River Aquifer 100 Table 21: Summary of Potential Landuse Impacts 110 Table 22: Environmental Flow Calculations 115 Table 23: Summary of Potential Impacts on Threatened Flora Species/Ecological Communities 118 Table 24: Summary of Potential Impacts on Fauna of Conservation Significance 121 Table 25: Summary of Potential Impacts on Threatened Fauna Species 121 Table 26: Summary of Potential Impacts on Migratory Species or its Habitat 122 Table 27: Environmental Risk Assessment Matrix 128 Table 28: Social/Cultural Environmental Risk Assessment 135 Table 29: Risk Assessment Matrix for Numerically Modelled Groundwater Potential Impacts 137 Table 30: CRCWW, Summary Construction Risk Assessment, Mulgrave River Aquifer 142 Table 31: CRCWW, Summary Operational Risk Assessment, Mulgrave River Aquifer 143 Table 32: CRCWW, Summary Construction Risk Assessment, Lake Placid Scheme 144 Table 33: CRCWW, Summary Operational Risk Assessment, Lake Placid Scheme 146 Table 34: Infrastructure Construction/Maintenance Cost/Benefit Comparison 148 Table 35: Operational Cost/Benefit Comparison 150 Table 36: Environmental Cost/Benefit Comparison between Lake Placid and Mulgrave River Aquifer Scheme 153 Table 37: EMP Structure 157 Table 38: Environmental Values 158

42/15610/99537 Mulgrave River Aquifer Feasibility Study Public Environment Report Figure Index Figure 1: General Aquifer Study Area and Locality 9 Figure 2: Aquifer Testing Areas 12 Figure 3: Proposed Borefield Layout 13 Figure 4: Example of Production Bore Construction 14 Figure 5: PER study area and WHA Boundary 25 Figure 6: Topography and Surface Drainage Features 42 Figure 7: CSIRO Soil Mapping Units 47 Figure 8: Soil Associations and Potential Acid Sulfate Soils Areas 48 Figure 9: Geological Units in the study area 50 Figure 10: Regional Ecosystem Conservation Status and Protected Species Observations 67 Figure 11: Vegetation Communities and Groundwater Dependencies 75 Figure 12: Groundwater Flow Directions 103 Figure 13: Mulgrave River Valley 104 Figure 14: Wet Season: River to Aquifer Interactions 105 Figure 15: Dry Season Interactions and Drawdown 106 Figure 16: Mapped Extent of Pond Apple (WTMA 2004) 126

Appendices A Guidelines for the Content of a Draft Public Environment Report B Cairns Regional Council General Policy 1:04:43 C Draft Environmental Management Plan D Numerical Groundwater Modelling Technical Report E Hydrogeology Report F Flora and Fauna Survey Report G Responses to Draft PER H General PER Information

42/15610/99537 Mulgrave River Aquifer Feasibility Study Public Environment Report Executive Summary

The Mulgrave River aquifer is currently the subject of a feasibility study as a supplementary urban water supply to Cairns City. As part of this study Cairns Regional Council Water and Waste have submitted the project to the Commonwealth for determination as to whether the project constitutes a “controlled action” under the provisions of the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The Commonwealth’s response is that there is potential for the project to impact on matters of National Environmental Significance (NES) (as defined by the EPBC Act), and that further information on the potential impacts of the project on matters of NES are to be submitted to the Commonwealth before a final decision can be reached. These further studies requested by the Commonwealth are to be commensurate with the Public Environment Report guidelines for the project issued to Cairns Regional Council Water and Waste (see Appendix A). This report conforms to the Commonwealth’s requirements for a Public Environment Report (PER) as necessary so that further information can be supplied to the Commonwealth. The primary objects of this PER are: 1. to present the necessary information requested by the Commonwealth in the format as prescribed under the guidelines for a Public Environment Report; 2. to present information on the likely impact of the project on matters of NES to Cairns Regional Council Water and Waste to assist in their deliberations of the environmental feasibility of the project.

The Proposed Action The proposed action is 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 (see Figure 1 for the study area). Each bore is to have an electric submersible pump and a connecting powerline that will form part of an underground pipe network alongside existing rural roads. This pipe network will ultimately connect into the Behana Creek water supply pipeline that exists adjacent to 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 to service the south of Cairns. It will be operated on an “as needs” requirement, only when other existing water supplies reach their allocated limits. On this basis, given the monsoonal conditions of the Wet Tropics, the borefield may not operate (under normal climatic conditions) for up to three months in the wet season of January to March (inclusive). For periods outside the wet season, abstraction will be determined by a combination of population demand for water, allocation from existing water sources, and environmental triggers for abstraction thresholds. Abstracted water is not intended to be banked (stored in a reservoir). The abstraction of water is intended only to occur when there is a shortfall from other existing sources.

The Public Environment Report The Commonwealth Department of the Environment, Water, Heritage and the Arts (DEWHA) have issued guidelines for the preparation of this Public Environment Report (PER). These relate to specific listed threatened species and their habitats that are considered to be of matters of National Environmental

42/15610/99537 Mulgrave River Aquifer Feasibility Study i Public Environment Report Significance. The PER must also consider those issues which may have an impact on general World Heritage and National Heritage values as a result of the construction and operation of the borefield. To demonstrate the level of impact studies associated with the proposed action, the PER includes numerical groundwater modelling, ecological, and hydrogeological assessments. These studies have identified the following impacts for the specific prescribed matters in the guidelines based on the available data and studies.

Impacts on Surface and Ground Water A technical groundwater assessment using a combination of review of hydrogeological information (including historical data from existing monitoring bores), data from installation of new bores, and a complex numerical groundwater modelling exercise has identified a relationship between water abstracted from the aquifer and surface water flows in the Mulgrave River and Behana Creek. In an average climatic year, abstraction of 15 ML/day on every day of the year will reduce river base flows by approximately 1%, and during prolonged dry periods (three dry years in a row – a one in sixty year event) will reduce river base flows by up to 4% during maximum abstraction. This impact assessment is based on the groundwater model which assumed the following parameters:

 15 ML/day abstraction, 365 days of the year.  Pumping for 12 hours/day (all on, all off).  No surface flow recharge of the aquifer from surrounding hills (i.e., there was no data on overland flow and minor steam flows so the model has underestimated the total amount of water entering the aquifer system, thereby adopting conservative input values to the model). This does not take into account the actual operational parameters of the borefield (i.e., borefield may not operate during the monsoon season; abstraction will be in response to demand and is not a set value, no water storage implemented). Therefore the actual water to be abstracted (on average) is potentially up to 30% less than that used in calibrating the groundwater model. The timing of the impact will also vary. It may take at least two weeks for water abstraction from the aquifer to affect surface water flows. In the interim, if there is rainfall in the headwaters of the river catchments the resultant impacts on the river base flow from abstraction (average seasonal impact of 1% reduction in base flow) would not be quantifiable as the river flow will increase as a result of the rainfall. On average (over a year with abstractions of 15 ML/day for every day of the year), the ratio of the volume of abstracted groundwater to the total volume of surface flow impact is predicted to be 1:1. The groundwater modelling predicted the following impacts based upon the above assumptions of the.

Impact (15 ML/day abstraction, 365 days a year, 12 Predicted Physical Impact hours per day).

Maximum Drawdown (m) 2

Extent of up to 0.5m Drawdown (km) 3

Number of Existing Licensed Bores Affected 1

Total Licensed Volume of Affected Bores (ML/year) 2

River Flow Impacts (ML/day) Reduction of 1% of the average dry season flow Reduction of 4% of the 1 in 60 year event dry season flow

Settlement (m) 0.03

Drawdown at Saline Interface (m) 0

42/15610/99537 Mulgrave River Aquifer Feasibility Study ii Public Environment Report Impacts on Matters of National Environmental Significance The Public Environment Report guidelines for the project have a number of specific requirements to be addressed. These primarily relate to assessment of impacts on specific listed species and also to assess the potential impact on general values of the Wet Tropics of Queensland World Heritage Area (WTQWHA) and the Great Barrier Reef Marine Park Area (GBRMPA) area as Matters of NES. Levels of threat and potential impact on these issues were derived from surveys of available literature and research information, supplemented with site inspections and the conclusions from the technical studies on likely impacts on groundwater and surface water conditions of the Mulgrave River. Specific matters of NES identified by the Commonwealth in the PER guidelines include:

 Southern Cassowary (Casuarius casuarius johnsonii);

 Waterfall Frog (Litoria nannotis) and Common Mistfrog (Litoria rheocola);

 Red Goshawk (Erythrotriorchis radiatus) and the Australian Painted Snipe (Rostratula australis) (also listed migratory);

 Flora species, Dendrobium Orchid (Dendrobium mirbelianum), Dendrobium nindii (an orchid), Eleocharis retroflexa (a sedge), Water Tassel-fern (Huperzia phlegmarioides); and

 Other listed migratory bird species that could occur in the project area that may be impacted by the proposal. Southern Cassowary (Casuarius casuarius johnsonii) – the immediate area of the borefield is intensive sugarcane area and no cassowary habitat present. The extent of impact of the maximum 15 ML/day abstraction drawdown extends to Behana Creek and a section of the Mulgrave River. Neither area has sufficient riparian vegetation to support cassowaries. Cassowaries are not present and will not be impacted in these areas. Waterfall Frog (Litoria nannotis) and Common Mistfrog (Litoria rheocola) – both frog species have no records as occurring within the Mulgrave River Aquifer Area and are entirely restricted in their distribution to the ranges of the bordering Wet Tropics of Queensland World Heritage Area. The nearest record is upstream of the aquifer area (in Behana Creek), in an area that will not be affected by drawdown associated with the aquifer and reduction in river flows. Red Goshawk (Erythrotriorchis radiatus) – there are no records of the red goshawk as occurring within Mulgrave River lowland coastal area. The preferred habitat for this species is not represented in the Mulgrave River Study Area and there is an extremely limited likelihood of the species being present in even a transient manner. Abstraction from the aquifer will have no impact on this species. Listed Flora Species – none of the listed flora species identified in the PER guidelines have records from the Mulgrave River Aquifer Area and were not located during field surveys for these species. It should be noted that of these species, only one (Eleocharis retroflexa, a sedge) is a terrestrial (aquatic ecosystem) obligate, the others being epiphytic/lithophytic. One flora species (Myrmecodia beccarii), an epiphyte listed under the EPBC Act, was identified in Mutchero Inlet (adjacent to but outside the study area). This species is not at risk of impacts from the proposed action. Listed Migratory Species – no EPBC Act listed migratory birds have been formally recorded within the Mulgrave River Aquifer Area and no areas of suitable freshwater wetlands or extensive intertidal areas exist within the study area. The closest intertidal flats identified as suitable habitat for migratory wader birds are located at the mouth of Mutchero Inlet, facing the open ocean and will not be impacted by

42/15610/99537 Mulgrave River Aquifer Feasibility Study iii Public Environment Report abstraction from the Mulgrave River aquifer. During the field surveys, the spectacled flying-fox (listed Vulnerable), white-bellied sea eagle (listed Migratory) and estuarine crocodile (listed Migratory) were observed in the study area. Crocodiles are resident in the Mulgrave River, and a small spectacled flying- fox camp was identified in mangroves in Mutchero Inlet. The White-bellied Sea Eagle was observed overflying parts of the lower study area near Mutchero Inlet. The proposed abstraction from the Mulgrave River aquifer will have no impacts on these species.

World Heritage Area Values This PER considered the potential impacts of the abstraction on the World Heritage values of the Great Barrier Reef Marine National Park (via reduced freshwater inputs into the GBRMP) and the Wet Tropics of Queensland World Heritage Area (WTQWHA). A small portion of the lower Mulgrave River within the aquifer area is included in the WTQWHA and is the only section of the WTQWHA potentially vulnerable to groundwater abstraction. Changes in the river base flow are predicted to be approximately 1% in a normal climatic year and approximately 4% for the one in 60 year extreme dry season event (three successive years where the rainfall was below average). This level of impact will have no quantifiable impact on in-stream erosion and sedimentation processes of World Heritage Areas. Modelling of the 15 ML/day abstraction has concluded that there will be no change in the ground or surface water salinity regimes of the aquifer or Mulgrave River and that there is no risk of exposure of acid sulfate soils and potential acid water drainage. Subsequently, there is no potential impact of abstraction from the Mulgrave River aquifer on the World Heritage values of the Great Barrier Reef Marine National Park.

Ecological Aspects Within the Mulgrave River Aquifer Area less than 10% of the original vegetation remains as a result of intensive development for sugar cane. The remnant vegetation consists of a discontinuous band of riparian vegetation on the verges of the major watercourses. Riparian vegetation comprises two community types, the first being the typical riparian terrestrial vegetation of the Mulgrave River and tributaries, consisting of a mosaic of mostly rainforest communities. The second community is represented by obligate (i.e. necessarily) groundwater dependent ecosystems (palm/tea tree swamps) to be found in the lower Mulgrave River, adjacent Mutchero Inlet, and extending a short way up the Mulgrave River into the aquifer study area. Native aquatic vegetation is also present, but is generally sparsely distributed and does not form distinctive communities. For an abstraction of up to 15 ML/day, there will be no quantifiable short or long term impacts on the viability of any of the riparian ecosystems in the aquifer area. Similarly, the small change in river flows as a result of the abstraction will not result in impacts on native aquatic vegetation. Notwithstanding, further studies are proposed in order to improve the understanding of the interaction between the groundwater abstractions, surface water flows and groundwater dependant ecosystems. There are no quantifiable cultural heritage impacts associated with the implementation of the Mulgrave River Aquifer Scheme to abstract up to 15 ML/day. The potential of altered hydrological regimes relative to the level of abstraction was also considered with respect to the potential increase in the distribution of the environmental weed Annon glabra (pond apple) and the noxious fish species Tilapia. An assessment of pond apple distribution identified that the species (shrub/small tree) was widespread, prevalent, and in some areas dominated sections of the riparian environment of the Mulgrave River and tributaries. The species occurs in both saline and freshwater environments. It was concluded that the abstraction from the aquifer and potential reduction in baseline flows of the river would neither favour nor disadvantage

42/15610/99537 Mulgrave River Aquifer Feasibility Study iv Public Environment Report this species, and the status quo would remain the same. A similar conclusion was reached regarding the spread of Tilapia. Tilapia (an introduced cichlid species) can tolerate both intermittently saline and freshwater environments, and its distribution and abundance would not be affected by the abstraction of water from the Mulgrave River aquifer.

Physical Aspects This PER examined the likelihood of contamination by saltwater intrusion, the potential for acid sulfate soils to be exposed and the potential impact of reduced flows on river morphology and dynamics. Modelling of the abstraction regimes under differing stream flow characteristics identified that the development of the borefield and subsequent drawdown in groundwater levels would not result in the generation of any actual acid sulfate soil conditions in the aquifer area. Therefore, no acid runoff would be generated by the aquifer scheme. The likelihood of saline water being introduced into the aquifer as a result of abstraction was identified as being absent under all conditions for abstraction of up to 15 ML/day. During extreme dry periods (1 in 60 year event where there are three successive years with the rainfall was below average), groundwater level drawdown at the saline interface in the northern and southern ends of the valley is expected to be approximately 0.1 m, which is insufficient to contaminate the groundwater, and would not result in changed salinity regimes within the Mulgrave River. Similarly, a change of less than 1% of river base flow in an average climatic year (and <4% during a one in 60 year dry season event (three successive years where the rainfall was below average)) will not result in impacts on river morphological processes, particularly sand and gravel movement, riffle and sand bar maintenance.

Cultural/Social The construction and operation of the Mulgrave River Aquifer Scheme has limited potential impacts on cultural and social values. The use of the Mulgrave River aquifer as a developed resource will likely preclude the use of the borefield area for urban development. This may come into long term conflict with growing population pressures about regional centres south of the Mulgrave River, particularly Aloomba, Charringa, Deeral and Fishery Falls. However, urban development within the Mulgrave River aquifer groundwater management area does not accord with the existing policies of the Department of Environment and Resources Management (DERM) who currently are a referral agency under the Integrated Planning Act 1997 for any such development within a groundwater management area. Protection of groundwater resources is a key aspect that is being addressed in the current regional planning framework (draft Far North Queensland Regional Water Supply Strategy, 2007). Correspondingly, the Far North Queensland Regional Plan 2009-2031 protects future catchment and storage areas as indicted in the Far North Queensland Regional Water Supply Strategy. The Mulgrave River Aquifer Scheme will limit the number of future bores and/or allocations within the groundwater management area of the aquifer. The majority of existing and unused allocations may be utilised without any impact from the aquifer scheme. Abstraction of up to 15 ML/day will have impacts on one existing registered bore. This will be mitigated by arrangements with the landholder, such as deepening the bore or otherwise restoring the existing functionality of the bore. Cultural heritage assessments will be required to be undertaken on a site specific basis when infrastructure planning and design is advanced, however there are no known cultural heritage values in the immediate vicinity of the borefield, or infrastructure development areas. Known sites are restricted to

42/15610/99537 Mulgrave River Aquifer Feasibility Study v Public Environment Report the foothills, gorges and river systems within the adjoining WTQWHA outside the aquifer area and will not be impacted.

Alternative to the Mulgrave River Aquifer Scheme The current water supply sources for Cairns are at or near their allocation/licence limits. The present augmentation options available are the Barron River Water Supply and the Mulgrave River Aquifer Scheme. Commonwealth and State Government agencies have approved the construction of infrastructure within the Barron Gorge National Park (part of the WTQWHA) for an abstraction amount of 50 ML/day from Lake Placid. This is a surface abstraction from the Barron River. An environmental risk assessment and cost-benefit analysis was undertaken comparing the current approved Lake Placid (Barron River) scheme with the Mulgrave River Aquifer Scheme (refer to section 8.2). The assessment considered cost, social and environmental considerations and concluded that the Mulgrave River aquifer is the preferred option as the next source to be developed for Cairns.

Proposed Safeguards and Mitigation Measures Physical construction of the borefield and associated infrastructure is outside the WTQWHA and will not require the clearing of any vegetation or fauna habitats of conservation significance. A draft Environmental Management Plan (EMP) for the mitigation of on site construction impacts has been prepared and is appended to this report (Appendix C). This draft EMP provides the basic framework for Cairns Regional Council Water and Waste to develop a more site specific EMP when the design of the borefields, associated delivery and treatment infrastructure has been finalised and construction methodologies known. The operation of the borefield and abstraction from the Mulgrave River aquifer will be subject to ongoing monitoring of both groundwater levels (via the existing bore monitoring network and the additional production and monitoring bores when established) and rivers flows in the Mulgrave River and Behana Creek. The primary mechanism for the ongoing monitoring of the borefield operation and potential impacts on the environmental values will be the installation and maintenance of monitoring bores and additional gauging stations on the Mulgrave River and Behana Creek, and subsequent development of detailed triggers and thresholds for operational rules for the borefield. The mechanism for the identification of the preliminary triggers and abstraction limits for the operation of the borefield have been identified in this PER, but will be reviewed following the next phase of investigations that will improve the understanding of the interaction between groundwater abstractions and surface water flows. Final trigger levels will be commensurate with the maintenance of environmental flows, and management responses may include allowing longer recharge intervals, reducing the number of bores in operation and reducing abstraction, or cessation of pumping altogether. The final EMP will be prepared when the approval conditions and requirements from statutory Queensland Government agencies become known. A summary of the mitigation measures proposed at this stage of the process is included in Table 1.

42/15610/99537 Mulgrave River Aquifer Feasibility Study vi Public Environment Report Table 1: Proposed Mitigation Measures for the Mulgrave River Aquifer Scheme

Mitigation Brief Description Relevant Section and Page Measures Number

Environmental A draft EMP is located in Appendix C. This EMP will be Section 9.1 page 156 Management Plan finalised pending the receipt of all approvals. The draft will be amended to include any works required to comply with any Appendix C conditions attached to approvals

A borefield operation plan in order to address stream flow monitoring recommendations and identify relevant trigger limits is to be contained within the EMP.

Recommended work practices will be included in the EMP to reduce the potential of environmental risk during all stages of the work – planning, construction and operational phases.

The EMP will address issues associated with water quality, soil, waste, emissions, cultural heritage and flora and fauna.

Reporting, contingency, monitoring and reporting strategies will be included within the scope of the EMP.

Borefield The BOP considers water levels to be retained in order to Section 9.2.1 page 158 Operations Plan properly manage stream flows required in this portion of the (BOP) catchment.

Trigger levels and threshold values are identified to determine flow rates and guide abstraction levels.

Monitoring bores will be installed – these will be the standard reference points to determine threshold values and trigger levels.

Environmental On-going monitoring will be undertaken during all phases of the Section 9.2.2 page 160 flow monitoring project. A monitoring strategy will be developed for this purpose. Additional gauging stations will be installed on the Mulgrave River and Behana Creek to monitor environmental flows and ensure they are not significantly impacted by abstraction from the aquifer.

Minimal physical Areas of remnant vegetation and habitat suitable for listed Section 2.3 page 15 disturbance species will not be cleared. The principle area of works Section 6.2.1 page 97 (including access tracks) will occur in areas that have been previously cleared for the purposes of agriculture and that have experienced significant disturbance.

Conclusions No matters of National Environmental Significance will be significantly impacted by the abstraction of water from the Mulgrave River aquifer. Neither the Wet Tropics of Queensland nor the Great Barrier Reef Marine Park World Heritage Areas will have values adversely affected by abstraction of groundwater from the Mulgrave River aquifer. For up to 15 ML/day abstraction, there will be no quantifiable impacts on groundwater dependent ecosystems. Social impacts are related to potential restrictions on land development and future groundwater allocations. The aquifer scheme will not affect existing allocations; however one private bore in the immediate drawdown sphere of influence of the borefield will be affected.

42/15610/99537 Mulgrave River Aquifer Feasibility Study vii Public Environment Report There are no quantifiable impacts on Cultural Heritage values within the aquifer area. Native Title is not applicable to the development of the borefield and associated infrastructure. The requirement for site- specific Cultural Heritage surveys will be reviewed when the planning and design elements of the scheme have been finalised. Technical feasibility studies have identified that exposure and oxidation of potential acid sulfate soils will not result from the abstraction of up to 15 ML/day. Similarly there will be no increase in the modelled level of salinity within the aquifer area. Land settlement as a consequence of abstraction from the aquifer will be minimal, with the modelling predicting up to 0.03 m. Any settlement will be gradual over several years, is anticipated to be relatively uniform over the area and is not expected to effect infrastructure or drainage. Groundwater quality is generally in compliance with existing water quality parameters for health, ecosystem maintenance and recreational values and will not be affected by abstraction from the aquifer. Groundwater monitoring has not identified the presence of contaminants in the form of pesticides or herbicides in the water table, and groundwater quality is higher than that of the Mulgrave River. Within the parameters of the models and assumptions used in the technical feasibility studies, abstraction of up to 15 ML/day has no quantifiable impacts on matters of National Environmental Significance as identified by the Commonwealth and from field and data investigations for this report, nor on adjacent World Heritage values. Table 2 summarises the expected impacts and differences between what is expected during the average climatic year (1% reduction in river base flows) and the prolonged dry periods (up to 4% reduction in river base flows).

Table 2 Summary of the Potential Impacts in Relation to Different Climatic Scenarios

Average Climatic Year Prolonged Dry Periods (three consecutive failed monsoon seasons, a 1 in 60 year event)

River base flow reductions Approximately 1% reduction. Reduction by up to 4%.

Potential saltwater intrusion The potential impacts of saltwater The potential impacts of saltwater intrusion intrusion are non quantifiable. are non quantifiable.

River morphological Unlikely to result in impacts on river There is the potential for minimal impacts processes processes. on river processes; however aquifer use will be managed.

Potential acid sulfate soil The predicted drawdown (see below) The predicted drawdown does not extend to exposure does not extend to areas of potential areas of potential acid sulfate soils. acid sulfate soils.

Flora and fauna habitats and It is highly unlikely that groundwater There is potential for a groundwater ecosystems dependant ecosystems will be dependant ecosystem to be affected, further affected. groundwater modelling (referred to as Phase 2 investigations) are to be undertaken.

42/15610/99537 Mulgrave River Aquifer Feasibility Study viii Public Environment Report Abbreviations

PASS/ASS Potential Acid Sulphate Soils/Acid Sulphate Soils

CRC Cairns Regional Council

CRCWW Cairns Regional Council Water and Waste

DEEDI Department of Employment, Economic Development and Innovation

DERM Department of Environment and Resource Management

DEWHA Commonwealth Department of the Environment, Water, Heritage and the Arts

DNRW Department of Natural Resources and Water (now DERM)

DPI&F Department of Primary Industries & Fisheries (now DEEDI)

EPA Environmental Protection Agency (now DERM)

EPBC Act Environment Protection and Biodiversity Conservation Act 1999

ESD Environmentally Sustainable Development

FNQRWSS draft Far North Queensland Regional Water Supply Strategy

GBRMPA Great Barrier Reef Marine Park Authority

GBRMPWHA Great Barrier Reef Marine Park World Heritage Area

GDE Groundwater Dependent Ecosystems

NCA Nature Conservation Act 1994

NES National Environmental Significance

ADWG Australian Drinking Water Guidelines

PER Public Environment Report

RE Regional Ecosystem

SPP State Planning Policy

ML Mega Litres

LE Listed Endangered

LV Listed Vulnerable

HNFY Historical No Failure Yield

WTQWHA Wet Tropics of Queensland World Heritage Area

42/15610/99537 Mulgrave River Aquifer Feasibility Study ix Public Environment Report Glossary of Terms

Abstraction The act of withdrawing or removing something. For the purpose of this report abstraction is the withdrawal of groundwater from the aquifer.

Acid Sulfate Soils Naturally occurring soils, sediment or organic substrates that generally occur in Quaternary marine or estuarine sediments confined to coastal lowlands (<5 m AHD). The soils contain iron sulphide minerals or their reaction products.

Acidic Water The result of the oxidation of acid sulfate soils (see oxidation). The water may include sulphuric acid and dissolved metals such as iron and aluminium.

Age of Pteridophytes The geological period(s) when spore-producing plants reached their greatest diversity, beginning in the Silurian Period (435 million years ago) and expanding through the Devonian and Carboniferous Periods until approximately 280 million years ago.

Alluvial Plain A relatively flat landform created by the deposition of sediment over a long period of time by river systems.

Alluvial Soil Fertile soil that has been transported by a river containing gravel, sand and silt.

Alluvium Soil or sediments deposited by a river or a moving water body. It typically consists of silt, clay, sand, and/or gravel.

Angiosperms Flowering plants.

Axilla The armpit or underarm, where the arm connects to the shoulder.

Aquifer A geological formation that is made up of water-bearing permeable rock or unconsolidated material allowing the storage and transmission of significant volumes of water.

Basalt A common mafic extrusive volcanic rock that is grey to black and fine grained due to rapid cooling of lava. It may contain larger crystals.

Base flow The proportion of stream/river flow that comes from groundwater and not runoff.

Bioregion An ecologically and geographically defined broad area. The biodiversity of flora, fauna and ecosystems characterise bioregions.

Brackish A term that is used to describe water that is more saline than freshwater, but less saline than sea/saltwater.

Borefield An area that contains the bores or wells through which the water is extracted.

Casque A helmet like structure that protects the head.

Catchment A catchment is a structure that captures water, with catchment area referring to an area that is drained by a river.

Chlorination The process of adding the element chlorine to water as a method of water purification.

Cretaceous Is a geological period extending from the end of the Jurassic Period (145 million years ago) to the beginning of the Paleocene Period (65.5 million years ago).

Coastal Plain An area of flat, low-lying land adjacent to a coast (sea) and separated from the interior by other features.

Coccygeal Vertebrae within the tailbone.

Colluvial Loose bodies of sediment and rock that have been deposited or built up at the bottom of slopes and transported by gravity.

Confined (Aquifer) Confined aquifers are permeable rock units that are generally deeper than unconfined aquifers. They are overlain by relativle impermeable rock that limits groundwater movement into and out of the aquifer.

42/15610/99537 Mulgrave River Aquifer Feasibility Study x Public Environment Report Diversity The variation of lifeforms within a given ecosystem.

Dorsal In biology, the dorsal end is situated at the back of an animal.

Drawdown A lowering of a reservoir or change in the hydraulic head in an aquifer. It is typically due to pumping or wells/bores.

Ecology Is the study of the distribution and abundance of life and the interactions between species and their environment.

Ecosystem A natural unit consisting of all plants, animals and microorganisms (biotic) functioning in an area together with non-living physical factors (aboitic) of the environment.

El Nino El Nino is part of the Southern Oscillation, a global coupled oceanic atmospheric phenomena. The term refers to the extensive warming of the central and eastern Pacific Ocean that leads to a major shift in weather patterns, in Eastern Australia it is generally associated with drier conditions.

Endemic In relation to bird species, endemic refers to any species found only in a specific area.

Environmentally Relevant Is an activity that will or has the potential to release contaminants into the environment Activity causing environmental harm. They are usually industrial or agricultural activities.

Epiphyte An organism that grows upon or attached to a living plant.

Erosion The removal or displacement of solids (e.g. sediment, soil or rock) usually by currents, such as wind, water or ice in a downward or down-slope movement.

Evolution Biological evolution is the process of change in the inherited traits of a population of organisms from one generation to the next.

Faulting A process of geology involving a planar rock fracture that shows evidence of relative movement.

Filtration A method of water purification where solids are separated from liquids.

Floodplain Flat or nearly flat land adjacent to a stream or river that experiences occasional or periodic flooding.

Floristics A branch of botany and biogeography that studies the distributions and relationships of plant species over geographic areas.

Fluvial A term used in geography and earth science that refer to all topics related to flowing water.

Folding A process in geology where one or a stack of originally flat and planar strata are bent or curved as a result of deformation.

Foliated Rocks that display any penetrative planar fabric (spatial configuration).

Forest An area with a high density of trees (>8 m in height and > 52 % canopy cover).

Granite A common and widespread intrusive, felsic, igneous rock with a medium to coarse texture. Granites can be pink to dark grey depending on their mineralogy.

Granite Soil Soil sourced from granite rocks, containing quartz, othroclase and other minerals.

Geology The science and study of the solid matter that constitutes Earth.

Geomorphology The study of landforms and the processes that shape them with an aim to determine the landform history and dynamics, and predict future changes.

Geophysics The study of Earth by quantitative physical methods, especially by seismic, electromagnetic and radioactivity methods.

Gondwana Was a southern supercontinent that existed about 500 to 200 million years ago.

Good Quality Agricultural Land that is capable of sustainable use for agriculture without causing the degradation of land Land or other natural resources.

42/15610/99537 Mulgrave River Aquifer Feasibility Study xi Public Environment Report Heaving A process in geology where there is a horizontal dislocation of a rock stratum at a fault.

Hydraulic Conductivity A property of soil or rock that describes the ease with which water can move through pore spaces or fractures. It depends on the intrinsic permeability of the material and the degree of saturation.

Hydrology The study of the movement, distribution and quality of water throughout Earth, addressing the hydrological cycle and water resources.

Hydrogeology A branch of geology/earthsciences that deals with the distribution and movement of groundwater through aquifers or other shallow porous media.

Hyporheic The saturated zone comprising the groundwater/surface interface of water courses.

Infiltration The process by which surface water (e.g. form rainfall) enters the soil.

Interbedded A term used in geology to describe beds/layers of rock lying between, or alternating with, beds of a different rock.

Intertidal Is the zone of the coast that is exposed to air at low tide and submerged at high tide.

La Nina La Nina is part of the Southern Oscillation, a global coupled oceanic atmospheric phenomena. The term refers to the extensive cooling of the central and eastern Pacific Ocean that is associated with an increased probability of wetter conditions in Eastern Australia.

Lacustrine Is the sedimentary environment associated within or adjacent to a lake.

Lithology A branch of geology that studies the mineral composition and structure of rocks.

Lithophyte A type of plant that grows in or on rocks.

Loam Soil comprised of sand, silt and clay.

Melaleuca Swamps Non-tidal, wooded wetlands occurring in or near coastal areas. They are seasonally inundated by fresh water and dominated by melaleucas (one plant species).

Metamorphic The term used to describe rocks that have been transformed by extreme heat and pressure.

Migratory Species Species that habitually move form one place to another at regular times of the year, for example bird species.

Monsoon A seasonal prevailing wind that lasts for several months that changes direction periodically.

Organic acid Organic compounds with acidic properties.

Oxidation In terms of acid sulfate soils, oxidation occurs when soils containing sulphide minerals are exposed to an oxygen rich environment, for example by lowering the water table, where the sulphide minerals react to produce sulphuric acid and release metals.

Parent Material The underlying geological material in which soil horizons form.

Peat An accumulation of partially decayed vegetation matter.

Permian A Geological Period that extends from approximately 299 million years ago to 251 million years ago.

Phreatophytic Ecosystems dominated by vegetation reliant on accessing the groundwater table for moisture.

Pleistocene The epoch (a geological time unit) from 1.8 million years ago to 10 000 years ago.

Prepollex A rudimentary additional digit on the preaxial side of the thumb of certain amphibians and mammals.

Quaternary A Geological Period that began after the Neogene Period, approximately 1.8 million years ago, to the present.

Rainforest Forests characterised by high rainfall.

42/15610/99537 Mulgrave River Aquifer Feasibility Study xii Public Environment Report Raptor Bird of prey, a type of bird often characterised by a hooked beak, sharp talons and keen eyesight.

Ratite A diverse group of large, flightless birds of Gondwanan origin, most of the species are now extinct. A ratite has no keel on their sternum, unlike other flightless birds.

Recharge A hydrological process where surface water moves to groundwater, often resulting in water table fluxes.

Regional ecosystem Communities of vegetation that are consistently associated with a particular combination of geology, landform and soil within a bioregion. RE’s are classified as either Endangered, Of Concern, or Not Of Concern.

Relative Humidity The amount of water vapour in a sample of air compared to the maximum amount of water vapour that the air can hold at a specific temperature (0-100%).

Remnant Vegetation Vegetation shown on a regional ecosystem or remnant map. Woody vegetation is mapped as remnant where the dominant canopy has greater than 70% of the height and greater than 50% of the cover relative to the undisturbed height and cover of that stratum (layer) and dominated by species characteristic of the vegetation’s undisturbed canopy.

Riparian The zone of the interface between land and a slowing surface water body. Plant communities along river margins are referred to as riparian vegetation.

Riverbed Is the channel bottom of a stream (stream bed) or river, it is the physical confine of the normal flow of water.

Reservoir A place for the storage of water for later use.

Runoff A term used to describe the movement/flow of water from rainfall or other sources over the land.

Savannah A grassland ecosystem with scattered trees or shrubs, the canopy does not close.

Schist Soils Schist rocks form a medium grade of metamorphic rocks. Schist soils are soils that are derived from a metamorphic origin rich in magnesium and potassium.

Sclerophyll A community of vegetation that has hard leaves and short internodes (distance between leaves along the stem). The thick cuticle on the leaves increases the resistance to drought.

Sedge A taxon of monocot flowering plants the superficially resemble grasses or rushes and common in wet areas.

Sedimentation The term used to describe the deposition by settling of suspended material.

Shagreened A rough surface on some species of amphibians and sharks, usually granular in nature.

Stratigraphic Units Layered rock units, mainly of a sedimentary or layered volcanic origin.

Substrate The material that rests at the bottom of the stream or river.

Taxa A taxon (plural of taxa) is a name designating an organism or group of organisms.

Tectonics A branch of geology that is concerned with the structures within the crust of the Earth and the forces and movements that have operated to create these structures.

Tertiary A Geological Period that marks the beginning of the Cenozoic Era, extending from approximately 65 million years ago to 1.8 million years ago.

Terrace A geological term for a flat platform of land created alongside a river or sea.

Threatened Species Any species (such as animals and plants) that are vulnerable to extinction in the near future. The International Union for Conservation of Nature divides threatened species into three conservation significance levels: vulnerable, endangered and critically endangered, depending on the degree of threat upon a given species.

Tubercle A round nodule or warty outgrowth.

42/15610/99537 Mulgrave River Aquifer Feasibility Study xiii Public Environment Report Turbidity The cloudiness/haziness of a fluid caused by suspended solids that are too small to settle out.

Tympanum The eardrum, the external hearing structure in amphibians, located just behind the ear, inflatable air sac on the neck of birds, auditory organ of insects and the membrane that closes on the capsule of some mosses.

Unconfined (Aquifer) The groundwater surface in an unconfined aquifer is the water table, where the groundwater is in direct contact with the atmosphere via pore spaces in the overlying soil/rock.

Vadophytic Ecosystem reliant on moisture within the soil profile but not accessing the groundwater table

Ventral In biology, the ventral end is situated at the belly/abdomen of an animal.

Volcanic Soil Soil that is created by one of two based volcanic activities, vent based or lava based.

Wader A long legged, necked and billed bird, such as a crane or stork that frequents the shallow water, especially in search of food.

Water shed The line or boundary separating neighbouring drainage basins or catchments.

Weathered Earth rocks, soils and minerals that have undergone decomposition due to direct contact with the atmosphere. Weathering occurs in situ or with no movement, it should not be confused with erosion.

Wetland An area of land consisting of soil that is saturated with water, for example swamps, marshes and mangroves.

Woodland Consists of areas with fewer and more scattered trees than forests (<20-50% foliage cover and >8 m in height), with an understorey of low trees, shrubs and/or grasses.

42/15610/99537 Mulgrave River Aquifer Feasibility Study xiv Public Environment Report 1. Introduction

1.1 Background As identified in 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 proposed 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 is to have an electric submersible pump and a connecting powerline that will form part of an underground pipe network alongside existing rural roads. This pipe network will ultimately connect into the Behana Creek water supply pipeline that exists adjacent to 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 will operate as a supplementary water supply only for the southern Cairns area. It will operate 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 groundwater allocation for the Mulgrave River aquifer of 15,000 ML/year (approximately 40 ML/day) from the Department of Natural Resources and Water (now part of the Queensland Department of Environment and Resource Management). The proposed action however intends to abstract varying quantities up to 15 ML/day with a maximum likely use of 3,000 ML/year (Overall Water Supply Strategy for Cairns, Cairns Regional Council, 2009). 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 groundwater levels and consequential impacts on environmental values as well as possible socio-economic impacts and landuse impacts. This PER assesses only the proposed action of the development of a borefield (to ten bores) to abstract up to 15 ML/day as outlined above. Should future demand require an increase in this abstraction level then this would be deemed a separate action and further assessment and referral would be needed.

1.2 Objectives and Scope The intention of this report is to provide sufficient information to the Commonwealth Department of Environment, Water, Heritage and the Arts (DEWHA) to enable the Department to make a decision as to the likely impacts of the implementation of the proposed action. The Commonwealth has indicated that this report should be in the form of a Public Environment Report (PER) based on the guidelines supplied to CRCWW by DEWHA under the provisions of the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). These guidelines describe certain aspects that should

42/15610/99537 Mulgrave River Aquifer Feasibility Study 1 Public Environment Report be included, with specific matters of National Environmental Significance (NES) to be addressed in the PER. These guidelines are presented in Appendix A. It should be noted that CRCWW is undertaking a two-phase approach to the investigations of the Mulgrave River aquifer. These two phases are:

 Phase 1: – aquifer abstraction feasibility, including an assessment of the sustainable yield and water treatment requirements within the context of development of a well field extracting up to 15 ML/day (approximately 5,500 ML/year); and – environmental assessment of the impact of the abstraction on specific environmental values and social/cultural values.

 Phase 2: – enhanced modelling of the aquifer to improve the understanding of groundwater and surface water interactions; – additional groundwater and stream flow monitoring; – community engagement; – acquisition of statutory landowner approvals; – borefield optimisation and detailed design; and – water treatment plant process selection and concept design. The information presented in this PER is derived from the Phase 1 studies of Mulgrave River Aquifer Scheme investigations. CRCWW have currently implemented the planning necessary for Phase 2, which will be complete by October 2010.

1.2.1 Commonwealth Public Environment Report The Mulgrave River Aquifer Scheme was referred to the Commonwealth in 2005 under the provisions of EPBC Act. A Public Environment Report (PER) was requested by the Commonwealth in order to determine whether the proposed action would result in significant impact on matters of National Environmental Significance (NES). Specifically, the PER has been requested to address under the Guidelines (refer to Appendix A) the following matters of NES:

 Southern Cassowary (Casuarius casuarius johnsonii) (LE), including regional status, population size and distribution within the project site and adjacent habitat that may be impacted by the project.

 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).

42/15610/99537 Mulgrave River Aquifer Feasibility Study 2 Public Environment Report  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 World Heritage and National Heritage values of the Wet Tropics of Queensland World Heritage Area (WTQWHA) adjacent to and within the project’s zone of influence (including the project site). The potential impacts (that may occur as a result of construction and long-term operations) to the ecology, hydrology and geomorphology of the project area and the project’s zone of influence as it relates to NES matters protected under Part 3 of the EPBC Act are described in this PER, and include:

 the construction and operation of the borefield and associated infrastructure on the environment in so far as it may impact on the World Heritage and National Heritage values, listed threatened species and listed migratory species described in above;

 detailed assessment of the nature and extent of the likely short-term and long-term relevant impacts;

 a statement as to whether any relevant impacts are likely to be unknown, unpredictable or irreversible;

 analysis of the significance of the relevant impacts; and

 any technical data and other information used or needed to make a detailed assessment of the relevant impacts. Further information regarding the potential for impacts to occur as a result of construction and operational phases are listed in Section 6 and 7 respectively.

1.2.2 Aquifer Abstraction Feasibility A separate, parallel investigation into the feasibility of the Mulgrave River aquifer as a viable supplementary water supply has also been completed by CRCWW (GHD, Mulgrave River Aquifer Project – Aquifer Abstraction Feasibility Study, 2007). For details regarding the abstraction scenarios that where considered for the proposed action in the feasibility studies refer to section 7.2.1. In addition to the factors considered in this PER, the Feasibility Study included consideration of the following:

 Identification of a sustainable aquifer yield including: – Hydrogeological assessment and aquifer characteristics; – Groundwater numerical modelling; and – Site investigations and aquifer testing.

 Infrastructure requirements for the development of the borefield;

 Infrastructure requirements for delivery of the abstracted water into CRCWW’s bulk water supply system;

 Water quality and required water treatment processes; and

 An environmental and technical feasibility risk assessment and cost benefit comparison with other options. This PER provides information derived from the technical studies used to support the Feasibility Study. Where relevant to the specific objectives of this PER, these technical studies have been included as Appendices, specifically:

 Appendix D contains the Numerical Groundwater Modelling Technical Report;

42/15610/99537 Mulgrave River Aquifer Feasibility Study 3 Public Environment Report  Appendix E contains the Hydrogeology Report; and

 Appendix F contains the Flora and Fauna Survey Reports.

1.3 Background to the Development of the Action

Demand for Additional Supply The Cairns Water Supply Scheme consists of the following water sources:

 Behana Creek; and

 Copperlode Falls Dam. Water supply planning has identified the need for an additional water source for Cairns. The draft far North Queensland Regional Water Supply Strategy (DNRW, 2007) has identified the Mulgrave River aquifer as a potential resource to augment the Cairns Water Supply Scheme. Consideration of the Mulgrave River aquifer as a supply has been examined and recommended in a number of reports undertaken or commissioned by DERM (formally DNRW), independent of the recent investigations by Cairns Regional Council (e.g. MWH 2005, Hyder Consulting 1999). The key options for a new major water supply source for Cairns have been identified (draft Far North Queensland Water Supply Strategy, DNRW 2007) as:

 Barron River water supply scheme abstracting water from Lake Placid with a proposed treatment plant at Kamerunga. This option would use a combination of run-of-river supply (unsupplemented supply) and controlled releases from Tinaroo Falls Dam (supplemented supply);

 Mulgrave River aquifer; and

 Mulgrave River surface water supply. The timing for the development of a new water source has been successively delayed due to a combination of water demand management strategies and operational improvements to maximise the efficiency of the current supplies. Current planning indicates that an additional water source is required by 2010 to maintain a reliable water supply system for Cairns. A salient feature of the existing water supply sources is the low reliability of the Behana Creek Supply1. It does not contribute to the reliable peak plant capacity during sustained dry years2 3. This means that any new source developed by 2010 to meet the shortfall in reliable production capacity is only likely to be required to operate for a few months a year. The evaluation of the scheme options indicated that the preferred option is the Mulgrave River Aquifer Scheme (refer to section 8). The Council of Australian Governments (COAG) ratified the National Water Initiative (NWI) under an inter-governmental agreement in June 2004. Under the NWI each state is required to prepare an NWI implementation plan. To date the Commission has accredited nine implementation plans, with Queensland’s plan which identified development of the Mulgrave River aquifer as a supplementary water supply, being accepted in 2006. Water pricing, and other issues related to implementation of the NWI are

1 The Behana Creek supply has a probability of failure of 1 in 5 years. 2 For example, after the sustained dry period of 2001-03, the supply from Behana Creek dropped to effectively zero in October 2003. 3 For example, after the sustained dry period of 2001-03, the supply from Behana Creek dropped to effectively zero in October 2003.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 4 Public Environment Report the responsibility of various Queensland Government agencies under their specific legislation. Where these apply to the Mulgrave River Aquifer Project, such issues will be dealt with directly between Cairns Regional Council and the Department of Environment and Resource Management. These issues are not required by the Guidelines for this Public Environment Report.

1.4 Relationship of the Action to Other Actions that May be Affected A review of the Commonwealth EPBC referral website was undertaken to determine if other actions proposed for the Mulgrave River Aquifer Area had been referred to the Commonwealth under the provisions of the EPBC Act. No actions other than the Mulgrave River Aquifer Scheme were listed. Therefore, the proposed abstraction of groundwater from the Mulgrave River aquifer will not have any relationship nor affect any other action proposed in the study area.

1.5 Current Status of the Action During the initial project investigations, the potential for impacts to result to matters of NES (defined under the EPBC Act) as a result of the proposed Mulgrave River Aquifer Scheme were identified. Cairns Regional Council Water and Waste lodged a project referral under the guidelines of the EPBC Act on 5 November 2005 to the Commonwealth Department of Environment and Heritage (known as DEWHA). On the 25 November 2005, the Department of Environment and Heritage deemed the proposed works to be a controlled action under the following provisions of the EPBC Act:

 the project may have the potential to impact on World Heritage listed areas (sections 12 and 15A of the EPBC Act) notably the Wet Tropics of Queensland World Heritage Area;

 may impact on listed threatened species and communities (sections 18 and 18A of the EPBC Act) particularly stream dwelling rare/endangered frog species known to live within the catchment of the project area; and

 may impact on listed migratory species (sections 20 and 20A of the EPBC Act) utilising wetlands in the catchment area. On 17 March 2006 the Commonwealth Minister for the Department of Environment and Heritage determined the level of assessment was to be commensurate with the requirements of a PER. The information required by the Commonwealth to properly assess the referral was provided in a draft PER. The draft PER was submitted to DEWHA and displayed for public comment. The public comments received have been incorporated into this report and are located in Appendix G. The presentation of the information contained within the PER is commensurate with the requirements of the guidelines located in Appendix A.

1.6 Consequence of the Action Not Proceeding Abstraction from the Mulgrave River aquifer represents a feasible water supply source to supplement the Cairns Regional Council’s existing water supply sources. Water for the immediate Cairns City area is currently drawn from the Copperlode Falls Dam and Behana Creek water supplies, all of which have its major catchments wholly or predominantly within the WTQWHA. The use of these existing surface water sources cannot be increased without quantifiable impacts on environmental flows and resultant impacts on World Heritage values and source reliability.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 5 Public Environment Report If the development of the Mulgrave River aquifer does not proceed, additional pressure will be placed on these existing water supply resources and on World Heritage values within the catchments. The Barron Scheme will then have to be developed at a higher social, economic and environmental cost (refer to section 8).

42/15610/99537 Mulgrave River Aquifer Feasibility Study 6 Public Environment Report 2. Description of the Action

2.1 Location

2.1.1 Project study area The Project study area comprises part of the catchment of the Mulgrave River and an 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 groundwater features, were used in developing the numerical groundwater 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 predictive 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.

2.1.2 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 (up to 9 metres annually in parts of the catchment) and takes in drainage sections of the Atherton Tablelands on its western boundary and a number of coastal tributaries. Some of these tributaries include 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 WTQWHA.

2.1.3 The Mulgrave River Aquifer System Within the Mulgrave River Catchment, the Mulgrave River alluvial aquifer system occupies an alluvial plain covering an area of approximately 200 km2 extending broadly from north of Gordonvale to Mutchero Inlet, at the mouth of the Mulgrave River. The Quaternary-aged alluvium overlies Permian-aged granitic

42/15610/99537 Mulgrave River Aquifer Feasibility Study 7 Public Environment Report and metamorphic bedrocks. To the north of Gordonvale, Quaternary-aged basalt outcrops to form Green Hill. The boundaries of the aquifer have generally been demarcated by the geological and soil associations of the Mulgrave River catchment. Typically, the aquifer boundary of influence approximates the 20 m AHD contour of the surrounding landscape. The east of the Mulgrave River aquifer is bounded by the Graham Range, the south by the saline environments and marine deposits of Mutchero Inlet, the west by the Bellenden Ker Range and the north by a groundwater divide extending from north of Gordonvale to Green Hill. This northern groundwater divide follows the catchment water shed boundary. The aquifer comprises alluvium deposited along the current and historical course of the Mulgrave River and is predominantly recharged by rainfall infiltration. The aquifer comprised alluvium deposited within the Mulgrave River Valley wherein the historical Mulgrave River created localised trenching. Later infill of the historical river trench developed the current Mulgrave River floodplain and river course, occurring in a drier, lower energy climatic period. Infill tends to be finer grained and more clayey/silty than the alluviums of the Mulgrave River Valley. These alluviums comprise coarser grained channel deposits within finer grained fan deposits, with sedimentary deposits varying from 45 m to 100 m and coarser sands generally occurring between 15 m and 45 m below surface. In some areas in the north of the aquifer basalt layers are interbedded through the alluvials. The Mulgrave River aquifer is unique in that it is a potential resource that retains very little of the original vegetation cover and natural environmental values generally occur in other undeveloped aquifer resources in north Queensland. It is also unique in that the aquifer is a self contained system, bounded by particular geomorphology characteristics that clearly demarcate the aquifer area from adjoining naturally vegetated areas - most of which are in the WTQWHA. Abstraction from the aquifer (as illustrated further in this report) will have limited to no quantifiable impacts on any values outside the immediate alluvium area of the aquifer.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 8 Public Environment Report Figure 1: General Aquifer Study Area and Locality

42/15610/99537 Mulgrave River Aquifer Feasibility Study 9 Public Environment Report 2.2 Detailed Proposal

2.2.1 Infrastructure components The water supply components required for use of the Mulgrave River aquifer as a water supply include the following:

 Bores and bore pumps;

 Connecting pressure mains to the new balancing storage at the Gordonvale waste transfer site;

 Pump station pumping from the balancing storage into the existing Behana pipeline;

 Connecting pipeline from the Behana main to the new Draper Road Water Treatment plant;

 Draper Road treatment plant (the treatment plant will be used to treat water from the Mulgrave River aquifer and the Behana Creek supply). The planning and design of the proposed plant will be undertaken after approval has been granted for the Mulgrave River aquifer abstraction activities. Implementation of the plant will be subject to conditions attached to state approvals required for the proposed works; and

 Connecting pipelines and pump stations, which will then ultimately deliver the treated water into the existing water supply infrastructure. The preliminary assessment of water supply components is based on developing and integrating the Mulgrave River Aquifer Water Supply with existing infrastructure. A single borefield of up to ten bores will be developed to supply the projected demand for 2015 (up to 15 ML/day). Refer to Figure 3 for scheme layout.

2.2.2 Preliminary Borefield Configuration The borefield layout was chosen on the basis of a hydrogeological desktop and field assessment, monitoring bore data provided by Department of Natural Resources and Water (now known as DERM) and actual pump tests on test bores established for the feasibility study. It should be noted that the actual borefield layout is indicative only, and is subject to the outcomes of further detailed studies that Cairns Regional Council Water and Waste are about to undertake. The hydrological and field assessments are included as Appendix E to this report. The key considerations in selecting the borefield area were based on review of the landuse, aquifer lithology and groundwater recharge, with the preferred potential sites for investigation and testing consisting of:

 areas of sandy vertical profile where seasonal recharge from rainfall appears significant;

 areas where runoff from the ranges or infiltration from smaller streams occur;

 areas with significant aquifer thickness at depth to maximise bore yields;

 areas within the Mulgrave River valley where a thick section of aquifer is overlain by semi-confining or confining units that may restrict interconnection with surface waters; and

 consideration of impacts on adjacent land owners and on existing landuses during the bore installation and pumping tests.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 10 Public Environment Report There were four sections of the Mulgrave River valley considered to have suitable aquifer conditions for groundwater supply development. Test Area 1 is on the fan deposits where a generally sandy profile occurs and annual rainfall recharge provides significant rises in groundwater levels. Areas 2 and 3 are along the flanks of the valley where sandy colluvial and fan sediments have been deposited, and recharge from Behana Creek and runoff from the ranges seasonally influences groundwater levels. Area 4 is located at the deepest section of the valley where over 20 m of possibly Tertiary age sand has been intersected above bedrock at 95 m depth, overlain by confining sandy clays and clays. Investigations required the drilling and testing of bores within each area to determine aquifer response to pumping and the potential sustainable yield in the long term. Test sites comprised a pump bore and several observation bores at various depths to monitor lateral and vertical response of the aquifer to pump drawdown. The results of the site investigations confirmed that the western section of the valley south of Gordonvale to approximately Meerawa has the best potential for groundwater supply development. Pump flows of between 30 and 50 L/s could be expected. Based on the results of the desk top hydrogeological studies, review of existing bore groundwater data and the results from the bore test sites, Test Area 2 was finalised for the development of the borefield. A preliminary borefield layout for Area 2 is shown in Figure 3. This layout was based on the following design criteria:

 All bores must be located on public land (primarily road reserve).

 Bores must be at least 400 m apart.

 Up to ten bores (up to 15 ML/day) are required in one borefield. The initial modelled arrangement of the bore fields at “Area 2” was iteratively derived via spreadsheet modelling using Theis (1935) analysis. The Theis (1935) analysis suggested a minimum bore spacing of 400 m. The borefield was determined through:

 Utilising the ideal minimum bore spacing;

 The likely maximum total groundwater abstraction required (15 ML/day);

 Likely achievable bore yields;

 Local physical constraints such as land ownership (road reserve versus private land); and

 Existing nearby groundwater users at each area. Three iterations of the modelling were conducted to determine a final bore field arrangement that minimised the drawdown impacts of abstraction.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 11 Public Environment Report Figure 2: Aquifer Testing Areas

42/15610/99537 Mulgrave River Aquifer Feasibility Study 12 Public Environment Report Figure 3: Proposed Borefield Layout

42/15610/99537 Mulgrave River Aquifer Feasibility Study 13 Public Environment Report 2.2.3 Construction and Operation of the Borefield and Associated Infrastructure As previously noted, implementation of the project will be undertaken with development of one borefield. The project is expected to deliver up to 15 ML/day from up to ten bores within borefield Area 2. The borefield will not be required at full capacity during the wet season, and the figure of 15 ML/day represents the maximum abstraction limit and not a constant rate. Development of the borefield involves the drilling of production bores within the borefield in the basic configuration as identified in Figure 3. Bores will be approximately 400 m (minimum) apart to reduce the risk of interference between adjacent bores. The production bores will be drilled and established in accordance with the methodology used to establish the existing test bores in the test areas. Figure 4 illustrates an example of how the production bores in Figure 3 may be constructed. The final design may vary depending on the stratigraphy and site-specific nature of each bore.

Figure 4: Example of Production Bore Construction Submersible electric pumps will be installed in each bore. Above each bore will be a secure concrete block housing with associated electrical, switchboard, communications and monitoring equipment. Each housing will be in a compound (no more than 100 m2) with security fencing. Electricity and communications may be supplied by either underground or overhead connection, depending on the circumstances of each location. All water supply pipes will be buried within existing road reserves with no requirement for any private land to be utilised. The connecting bore riser mains are of 150 mm diameter with the main trunk supply mains being 500 mm diameter. None of the proposed works are within or adjacent to the Wet Tropics of Queensland World Heritage Area.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 14 Public Environment Report As part of the overall monitoring program for the Mulgrave River Aquifer Scheme, Cairns Regional Council Water and Waste have committed to the installation of additional gauging stations on the Mulgrave River and Behana Creek to monitor variability in flows. The major operational consideration of the borefield will be the relationship between water abstraction and influences on environmental river flows. Environmental flow assessments are presented in Section 7.5 of this PER, and these flows are the basis for the identification of the operational limits of the abstraction. Other operational considerations of the borefield include:

 Pump hours per day: Best practice is to pump all boreholes simultaneously for 12 hours per day.

 Recharge of aquifer: All boreholes to be rested simultaneously for 12 hours per day to allow recharge of the aquifer.

 Area 2 borefield constraints: – Maximum flow per borehole = 50 L/s; – Bore drilled depth = 55 m; – Pumping drawdown = 25 m; and – Assumed minimum bore spacing = 400 m.

2.2.4 Environmental Management Plan A draft Environmental Management Plan for the construction and operation of the borefield and associated infrastructure for the project has been prepared and is presented in Appendix C. Additional mitigation measures are discussed in Section 9 of this report. The final EMP will reflect the requirements of development conditions and approvals as identified by Queensland Government agencies during the Integrated Development Assessment Scheme (IDAS) process. A key aspect of the Environmental Management Plan will be detailed Borefield Operating Rules which will be finalised when details of the Phase 2 investigations (to commence shortly) are known. It is expected that the final borefield configuration and characteristics of the borefield operation necessary to establish parameters for Environmental Flow Monitoring will be known by the end of the Phase 2 studies.

2.3 Additional Licences / Permits and Approval Requirements required by the Project

2.3.1 State Legislation and Planning Approvals Framework The following outlines the key legislative and planning issues and mechanisms that must be addressed in order for the Mulgrave River Aquifer Project to be implemented. It should be noted that some of the legislative requirements, such as applications for Environmentally Relevant Activities (ERAs) and their implementation mechanisms, including Environmental Management Plans, are site and locality specific. They are also specific in terms of such things as construction methodologies, preparation of erosion and sediment control plans and the like. This level of detail will be addressed as part of the Phase 2 investigations to commence shortly, envisaged for completion by October 2010.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 15 Public Environment Report Queensland Integrated Planning Act 1997 It should be noted that the IPA is due to replaced by the Sustainable Planning Act 2009 (SPA). The Act was passed on the 16th September 2009 and is due to come into effect late 2009. Until the SPA commences, the IPA continues to have effect and so there are no changes to any existing processes at this stage. Planning instruments made under the IPA will continue to have effect under the SPA. Under the Integrated Planning Act 1997 (IPA), developments are categorised as ‘Impact Assessment’ or ‘Code Assessment’. However, all water-related developments are code-assessed, meaning it does not require public notification and no other parties (except the applicant) can appeal a decision. The ‘code’ can be an actual code defined by regulation or simply the laws and policies of DERM. In the case of the Mulgrave River Aquifer Project, DERM will assess the project against the department’s own policies and demonstrated project need. DERM will be the Assessment Manager for this project and will assess the application with respect to the water related development and may:

 attach certain conditions to any development approval;

 approve only part of the application;

 give a preliminary approval only; or

 refuse the application. The two types of approvals under the IPA are:

 Preliminary approval – which is less common and provides for approval in principle (subject to imposed conditions) where the applicant may be seeking finance prior to commencement of works.

 Development permit – most common procedure and approves the commencement of works. Most water-related developments will receive a development permit without the need for preliminary approval. In this instance Cairns Regional Council Water and Waste will be applying directly for a Development Permit. Applications for the proposed action will be made and assessed under the provisions of Queensland IPA. This legislation guides how development applications are to be assessed and identifies the assessment manager and referral agencies to be involved in the assessment process. Schedule 8 of the Queensland IPA specifies that operational works (including construction of bores) for the purposes of taking or interfering with water under the Queensland Water Act 2000 is classified as “assessable development”, and the proposed action will require an approved development permit from DERM who will assess the project against the requirements of the Water Act 2000.

Applicants are required to complete the standard IDAS development ‘Form A’ – plus the relevant water- related ‘Form K1’ (artesian bore/subartesian bore). Mandatory information required on Form A and Form K includes:

 an accurate description of the land;

 the consent of the land owner or owners;

 the consent of the resource manager;

42/15610/99537 Mulgrave River Aquifer Feasibility Study 16 Public Environment Report  a description of the development; and

 the signatures of all interested parties. The State is the owner of road reserves and esplanades. Therefore, as the proposed borefield development and water delivery infrastructure is to be sited in road reserve, owner’s consent must be provided by DERM. Additionally, all construction work for the water supply and treatment infrastructure (including the bore housings, construction of delivery infrastructure, the treatment plant and reservoir) will be classed as operational works under IPA. An IDAS application is required to be submitted to DERM, who as assessment manager for the operational works component of the project, will seek comment from various statutory government agencies. IPA specifies the level of assessment and supporting information that will be required by the statutory government authorities in order to assess the project under the provisions of their own individual legislation.

Queensland Coastal Protection and Management Act 1995 Under the Coastal Protection and Management Act 1995, the State Coastal Management Plan (SCMP) and subsequent Regional Coastal Management Plans have the status of State Planning Policies for the purpose of making and amending Planning Schemes, and assessing and deciding development applications. The Queensland coastline has been divided into eleven regions with a Regional Coastal Management Plan to be prepared for each region. The Wet Tropical Coast Regional Coastal Management Plan is a statutory instrument under the Coastal Protection and Management Act 1995 (Coastal Act). The Plan is designed to guide decisions by State and local governments about coastal development and management on the coast between the former Douglas and Johnstone Shires. The Coastal Act also binds the Commonwealth as far as the legislative power of the Parliament permits. The Wet Tropical Coast Regional Coastal Management Plan, and the State Coastal Plan, also has the effect of State Planning Policies under the Integrated Planning Act 1997. The Wet Tropical Coast Regional Coastal Management Plan addresses matters of international, national, state or regional importance within the region. Matters of international, national and state significance are identified by State and Commonwealth legislation and plans, including the State Coastal Plan. In the context of the Mulgrave River Aquifer Project the key regional policies and principles that a development application will be assessed against include:

 Section 2.1 Coastal use and development, ‘use and development of the coastal zone occurs in an ecologically sustainable manner.’

 Section 2.2 Physical coastal processes, ‘the coast is managed to allow for natural fluctuations to occur, including any that occur as a result of climate change and sea level rise, and provide protection for life and property.’

 Section 2.4 Water quality, ‘water quality in the coastal zone is maintained at a standard that protects and maintains coastal ecosystems and their ability to support human use.’

 Section 2.8 Conserving nature, ‘coastal ecosystems, including their ecological processes opportunities for survival, biological diversity and potential for continuing evolutionary adaptation, are maintained, enhanced and restored.’

42/15610/99537 Mulgrave River Aquifer Feasibility Study 17 Public Environment Report As a statutory instrument under the Coastal Act, the Wet Tropical Coast Regional Coastal Management Plan guides relevant decisions by State and local governments and the Planning and Environment Court. State Government is required to consider the Wet Tropical Coast Regional Coastal Management Plan when making relevant decisions about coastal management in the Mulgrave River Aquifer Area.

Queensland Vegetation Management Act 1999 The management of vegetation in Queensland is governed by the Vegetation Management Act 1999 (VMA). Remnant vegetation is mapped by the Queensland Herbarium, and classified according to its bioregion, soil/geology/topography and floristic composition. Depending on these classifications and the proportion of estimated pre-European settlement coverage that remains these ecosystems are assigned different levels of protection. To clear some types of remnant vegetation (for example, where clearance is required for pipeline and reservoir construction), an approval to undertake operational works (including clearance of vegetation) is required. Vegetation communities (termed regional ecosystems in the VMA) listed as Endangered and Of Concern under the schedules of the Vegetation Management Regulation 2000 are mapped in the area of the proposed development. Vegetation classed as such cannot be cleared except in clearly defined circumstances. Vegetation in the study area is not mapped as remnant hence no approvals under the VMA are required.

Queensland State Development and Public Works Organisation Act 1971 This Act outlines the process required to gain approval for public and other essential infrastructure. As relevant to the Mulgrave River Aquifer Project, the Act sets out the structure and assessment protocols for supporting information necessary for statutory and/or referral agencies to assess and comment on the project as submitted under the IDAS process (under IPA). In particular, the Act sets out the necessary framework for information referral, notably that for an Environmental Impact Assessment Study (EIAS), which would be the key supporting information requirement to government agencies under IPA. An EIAS undertaken under the guidelines of this Act is recognised by the Queensland and Commonwealth Government as an accredited process to gain approval from statutory authorities for public infrastructure.

Queensland Environmental Protection Act 1994 The Queensland Environmental Protection Act 1994 (EPA) requires specific development approval for Environmentally Relevant Activities (ERA) defined in the Act. ERA’s include facilities such as a municipal water treatment plant, and actions such as dredging material from the bed of any water body. A list of ERAs arising from the proposed action has not been finalised, final detail from the design and construction aspects of the Phase 2 studies is required to determine the total ERAs.

Queensland Water Act 2000 Most water related developments require assessment and approval under the Integrated Planning Act 1997 (IPA) and the Water Act 2000 (the Water Act). While some developments are exempt from approvals or are self-assessable, others require a development approval from DERM or the relevant local government. A development approval is required from DERM prior to the commencement of any bore construction, including test drilling. Cairns Regional Council Water and Waste currently hold a ‘Licence to Take Water’ from the Mulgrave River Alluvium. This licence provides an allocation of 15,000 ML/year from locations identified on the

42/15610/99537 Mulgrave River Aquifer Feasibility Study 18 Public Environment Report licence. To take water from other locations of the Mulgrave River Alluvium, as may be identified by Phase 2 of the investigations, it is envisaged that an amendment to the water licence will be required. In accordance with the Water Act, an application to amend a water licence must be dealt with as if it were an application for a water licence and proceed through the public notice requirements. Cairns Regional Council Water and Waste has not yet applied for an amendment to the existing water licence or any approvals for the construction of bores or associated infrastructure. The Water Act provides for protection of water resources through development of Water Resource Planning and their attendant Resource Operation Plans (ROP). Water resource planning for the Mulgrave River catchment is not yet available and the Mulgrave River is currently not subject to a ROP. A Riverine Protection Permit under the Water Act is required to undertake works that involve the destruction of vegetation, placement of fill or excavation activities within a watercourse (as defined under the Water Act).

Queensland Aboriginal Cultural Heritage Act 2003 The Aboriginal Cultural Heritage Act 2003 (CHA) confers a Duty of Care upon Cairns Regional Council to ensure that all reasonable and practical measures have been undertaken to minimise and mitigate impacts of the project on Cultural Heritage Values. Search requests were made to DERM for any registered sites on the Cultural Heritage Register and Database within the general study area. Registered sites are entirely restricted to within the WTQWHA, with no sites on either the register or the database located within the Mulgrave River Aquifer Area. Discussions were also held with Project Officers of the Aboriginal Rainforest Council. Their primary interest was in the potential impact of the project on story places and sites. However, all sites identified were within the WTQWHA, the closest area being the Behana Gorge (not to be affected by the project). The borefield area is within a highly modified rural environment, dominated by intensive sugar cane farming. Under the Duty of Care guidelines of the CHA, it is noted that such areas are very unlikely to retain any areas of cultural heritage significance and further assessment within the borefield area would not be required.

2.3.2 Licences, Permits and Approvals Summary Environmental licences, permits and approvals that may be required for the project are summarised in Table 3. Cairns Regional Council Water and Waste or its Contractors will need to obtain all necessary approvals.

Table 3: Legislative Assessment Requirements

Legislation Responsible Authority Trigger Licence / Permit / Approval

Environment Protection and Department of Potential impacts on Matters Submission of Public Biodiversity Conservation Act Environment and of National Environmental Environment Report. 1999 - Commonwealth Resource Management Significance. Commonwealth to assess PER and advise of outcome.

Environmental Protection Act Department of Where ‘serious and material Duty to notify. 1994 - Queensland Environment and environmental harm’ is Resource Management caused or threatened. Application for ERAs under IDAS for any applicable listed action.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 19 Public Environment Report Legislation Responsible Authority Trigger Licence / Permit / Approval

Water Act 2000 - Queensland Department of Use of groundwater Development permit for Environment and resource. installation of bores in a Resource Management groundwater declared area. Development of bores. Note – CRCWW currently hold Works within a watercourse. a licence for an abstraction of 15,000 ML/year, amendment to this may be required.

Coastal Protection and Department of Planning policies related to Demonstrated compliance with Management Act 1995 - Environment and this Act have force of law in Sections 2.4 (water quality), 2.6 Queensland Resource Management relation to the project. (cultural heritage) and 2.8 (conserving nature). A development approval sought through the Integrated Development Assessment System (IDAS). Application to be accompanied by demonstrated compliance with the policies in the State Coastal Management Plan and Wet Tropical Coast Coastal Management Plan.

Vegetation Management Act Department of Clearing of mapped remnant Required only if vegetation is 1999 - Queensland Environment and vegetation. required to be removed on Resource Management freehold land that is not zoned Clearing of riparian either urban or special purpose, vegetation. or vegetation is within a riparian area.

Integrated Planning Act 1997 - Cairns Regional Council Referral of the project to Development application to be Queensland statutory authorities for accompanied by supporting assessment under individual documentation. Project referral legislation. to DERM.

Land Act 1994 - Queensland Department of Occupation of road reserve, Permit to occupy road/rail Environment and rail corridor and esplanade reserve required. This permit Resource Management by infrastructure. requires agreement with Main Roads and Qld Transport/Qld Lot excision from freehold Rail to be lodged with land for construction of application. infrastructure (if needed). Application to Cairns Regional Council for reconfiguration of a lot.

Aboriginal Cultural Heritage Act Department of Employment of Traditional Only applicable in the instance 2003 - Queensland Environment and Owners for site clearance of earthworks involving clearing Resource Management prior to earthworks and of native vegetation for the removal of native reservoir and treatment facility. vegetation. Not required for borefield area or for pipelines within road reserve where landuse is intensive rural.

Transport Infrastructure Act Department of Transport Road and rail crossings as Agreement required with 1995 - Queensland and Main Roads well as occupation of road Queensland Transport and and rail corridor land. Department of Main Roads for the crossing of rail & road corridors of water supply pipelines.

Native Title Act 1993 - Department of Infrastructure in areas with No area listed under the Queensland Environment and Native Title Claim or areas National Native Title Tribunal Resource Management awaiting determination. Database and Qld Register is included in the study area.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 20 Public Environment Report It should be noted that Queensland legislation and the policies and principles of the government agencies responsible for assessment of the various permits and license applications are regularly amended. Consequently the information listed in Table 3 is provided as a guide only.

2.3.3 State Planning Policies A State Planning Policy (SPP) is a statutory planning instrument that relates to matters of State interest. These policies must be considered by the Minister in the Community Infrastructure Designation process pursuant to Section 2.6.7(2)(b) of the IPA. These SPPs are incorporated into the planning schemes of Local Governments as deemed applicable. The general principles of the SPP considered for the Aquifer Feasibility Study are outlined below.

SPP1/92: Development and the Conservation of Good Quality Agricultural Land State Planning Policy 1/92 addresses the conservation of good quality agricultural land (GQAL) and provides guidance to local authorities on how this issue should be addressed when carrying out their range of planning duties. This policy commenced on 18 December 1992. Areas mapped as GQAL were considered in the Aquifer Feasibility Study and assessed on the basis of the principles of the SPP applicable to the study area, in particular Principle 2 of SPP 1/92: The alienation of some productive agricultural land will inevitably occur as a consequence of development, but the Government (QLD) will not support such alienation when equally viable alternatives exist, particularly where developments that do not have very specific locational requirements are involved.

The borefield is located in areas mapped as GQAL under the Cairns Plan. Therefore, the project impacts need to be measured against the objectives of this SPP. In considering the feasibility of the Mulgrave River Aquifer Project, it was considered that as the development of the borefield has very specific locational requirements (i.e. within the aquifer area), that Principle 2 of this SPP is upheld. It should however, be noted that it is not intended that any of the borefield infrastructure requirements be located within any productive land, and that infrastructure would be located within road reserves and easements. This may not always be achievable, and in those instances where borefield infrastructure impinges on agricultural usage then the provisions of Principle 2 of the SPP must be considered and taken into account in any landowner negotiations.

SPP2/02: Planning and Managing Development Involving Acid Sulfate Soils This policy came into effect on 18 November 2002. The general aquifer has been defined as predominantly that area of the Mulgrave River valley below the 20 m AHD contour. Under the provisions of this SPP any development (in this instance the borefield development and abstraction from the aquifer) proposed to be below 20 m AHD must consider the potential of the development dewatering and exposing potential acid sulfate soil. Acid sulfate soils have been mapped under Cairns Plan for the lower section of the Mulgrave River. These have been mapped by the then Department of Natural Resources and Water (now DERM) based on research undertaken by the Queensland Acid Sulfate Soils Investigation Team (QASSIT). The acid sulfate soil areas are mapped as occurring in tidal areas containing mangroves and predominately marine and organic muds and silts.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 21 Public Environment Report The proposed works will occur in the freshwater reaches of the Mulgrave River where it is unlikely acid sulfate soils occur. The numerical modelling and assessment of the potential impact of abstraction from the Mulgrave River aquifer has predicted that there are no likely impacts arising from the project on acid sulfate soils. Therefore, this SPP has been considered and assessed in the Aquifer Feasibility Study.

SPP1/03: Mitigating the Adverse Impacts of Flood, Bushfire and Landslide This policy came into effect on 1 September 2003. The purpose of this policy is to set out the State Government’s interests with regard to the natural hazards of flood, bushfire and landslide and how these matters are to be addressed when carrying out assessment for development purposes. Under the Integrated Planning Act 1997 (IPA), this SPP has effect when development applications are assessed; when planning schemes are made or amended; and when land is designated for community infrastructure. Flooding is an issue throughout the general study area, with areas of flood inundation clearly mapped under the Cairns Plan. None of the borefield area (including the reservoir or treatment plant) is located within a flood prone area, however some water delivery infrastructure will necessarily have to traverse Behana Creek. Behana Creek is a flood prone system however flooding is generally confined to the high points of the banks of each system. The water delivery infrastructure in the vicinity of any waterway would be designed to cope with flood events. Bushfire and landslide consideration is applicable to the development of the reservoirs and treatment plant. The design and construction will incorporate the outcomes of geotechnical investigations of the proposed sites for these facilities. In the case of bushfires, the sites will largely be cleared of vegetation with significant cleared buffers between the facilities and any adjacent vegetation. The buffer will enable access for fire fighting equipment and ameliorate the likely risk of bushfire impacts on the facilities. Bushfire hazard risk areas have been mapped for the study area, and include areas of sugarcane cultivation in the risk assessment. Sugar cane is no longer regularly burnt prior to harvesting, but the borefield location and infrastructure design must take into account the possibility of sugar cane fires immediately adjacent to these structures.

Environmental Protection (Water) Policy 2009 Part 5 of the Environmental Protection (Water) Policy 2009 (EPP (Water)) details the “Management of activities” by administering authorities. The various sections impose a duty on the administering authority to consider a range of water quality aspects including acid sulfate soils, stormwater management and wastewater treatment. A number of agencies are involved in the management of this policy. The EPP (Water) was considered in the Aquifer Feasibility Study in the context of the potential impact of the project on the contamination of the aquifer through salt intrusion as a result of abstraction, and in terms of contamination of waterways through the exposure of acid sulfate soils. In both instances the predicted impacts on both have not been able to be quantified and the potential for impact of abstraction on both of these issues is considered to be negligible.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 22 Public Environment Report 3. Methodologies

3.1 Background and Approach The PER is framed around the guidelines provided by the Commonwealth (Appendix A), and addresses both the specific matters identified in the Guidelines and 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 groundwater 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. The key components of the PER include (but are not limited to):

 Specific matter as listed in the Guidelines;

 Desktop and database assessments and field investigations of potential flora and fauna species within the study area;

 Environmental flow assessments including bore testing and modelling;

 Risk assessments; and

 Stakeholder consultation. The following section provides the methodologies that were utilised in addressing the key components as listed above.

3.2 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. The area of influence of the Mulgrave River aquifer, in general, is defined by the occurrence of deep Quaternary alluvium occurring below the 20 m contour interval, covering an expanse of approximately 200 km2 both north and south of the Mulgrave River. This is a very large area, predominantly cleared for sugar cane, but retaining verges of riparian vegetation of varying ecological integrity along the banks of the major watercourses of the Mulgrave River and Behana Creek.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 23 Public Environment Report The study area for the PER does not include the entire aquifer area, as information from hydrogeological studies and the numerical groundwater report have refined the area of potential impact for the construction and abstraction of the borefield. The area of study for the PER extends from the Mulgrave River crossing of the Bruce Highway (near Gordonvale), southwards along the Mulgrave River to the marine environment interface at Deeral, approximately 25 km downstream. East to west the study area for the PER follows the 20 m contour of the Graham Range (eastern side of the Mulgrave River valley) and extends to the 20 m contour on Mt Sophia/Bellenden Ker Range on the western side. The study area includes Behana Creek to a point approximately 500 m westwards of the Bruce Highway at which point the creek no longer forms part of the Mulgrave River aquifer and sandy alluvium transitions to granite as the base geology. The Wet Tropics of Queensland World Heritage Area intersects the Mulgrave River aquifer in only one location within the PER study area (see Figure 5), the eastern bank of the Mulgrave River from an outlying spur of the Graham Range. To the south of the study area the WTQWHA is entirely marine (Mutchero Inlet section) and while this forms the southern boundary of the study area for the purposes of the PER, this section of the WTQWHA does not have any direct interaction with the Mulgrave River aquifer and is not within the aquifer area. The WTQWHA boundary is approximately 4 km further up Behana Creek from the PER study area, and being upstream of the aquifer, on different geology, there are no direct or indirect connections between the groundwater resources of the Mulgrave River aquifer (on alluvium) and the WTQWHA (on granite and at a starting elevation of approximately 40 m AHD (Australian Height Datum)). The PER study area in relation to the WTQWHA boundaries are shown in Figure 5.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 24 Public Environment Report Figure 5: PER study area and WHA Boundary

42/15610/99537 Mulgrave River Aquifer Feasibility Study 25 Public Environment Report 3.3 Overview of Ecological Values Descriptions The following three key methodologies were used to identify Ecological values that may be potentially affected by the construction and operation of the proposed borefield:

 The initial ecological values identified as the “specific content” requirement of the Commonwealth PER Guidelines to Cairns Regional Council Water and Waste (refer Appendix A). These specific content guidelines required assessment in regard to a list of nominated fauna and flora species and the potential impact to general World Heritage values via salinity intrusion, ground settlement, and exposure of potential acid sulfate soils (PASS) amongst others.

 A desktop database review on available published data.

 A field investigation to assess the likelihood of impact as a result of the proposal upon fauna and flora habitat values.

3.4 PER Guidelines

3.4.1 Specific Content Matters The specific content matters required to be investigated and assessed in this PER as identified by the Commonwealth guidelines are listed in Table 4.

Table 4: Summary of NES Matters Protected under Part 3 of the EPBC Act

Common Name Species EPBC Act Status Qld NCA4 Status

Southern cassowary Casuarius casuarius johnsonii Endangered Endangered

Red goshawk Erythrotriorchis radiatus Vulnerable Endangered

Australian painted snipe Rostratula australis5 Vulnerable & listed Vulnerable Migratory

Torrent tree frog Litoria nannotis Endangered Endangered

Common mist frog Litoria rheocola Endangered Endangered

Mangrove orchid Dendrobium mirbelianum Endangered Endangered

Blue orchid Dendrobium nindii Endangered Endangered

Sedge Eleocharis retroflexa Vulnerable Vulnerable

Layered tassel-fern Huperzia phlegmarioides Vulnerable Vulnerable

The above list does not exclude the consideration of other NES species that may be present in the area, identified either through database searches or through observations in the field. Further details of the above are provided in the Field Survey Results of this PER.

4 Queensland Nature Conservation Act 1994 and associated Nature Conservation (Wildlife) Regulation 2006 5 Currently recognised under Qld legislation as syn: with Rostratula benghalensis australis

42/15610/99537 Mulgrave River Aquifer Feasibility Study 26 Public Environment Report 3.4.2 World Heritage and National Heritage Values The following World Heritage and National Heritage values of the Wet Tropics of Queensland World Heritage Area (WTQWHA) were identified in the PER guidelines as within the aquifer project zone of influence, and/or adjacent to or within the project area. Note that the National Heritage values of the Wet Tropics of Queensland are the same as the World Heritage values. The project area potential zone of influence is generally demarcated as that area within the Mulgrave River catchment on coastal alluvium (the “aquifer”) below 20 m AHD. A summary of the World Heritage values within/adjacent to the aquifer project area is presented in Table 5. The specific impacts are discussed further in this report.

Table 5: Summary of World Heritage Values within/adjacent Aquifer Area of Influence

Natural Criterion for World Heritage Listing Representation of Values adjacent/within WTQWHA

Outstanding examples representing the major stages Representatives from Age of Pteridophytes, with numerous ferns present of the earth’s evolutionary history. in remnant riparian areas. Primitive Gondwanan era angiosperm families represented, including Annonaceae, Eupomatiaceae, Myristicaceae, Lauraceae, Monimiaceae are present in rainforest riparian areas of the Mulgrave River and tributaries Representatives of mixing of continental biota (flora and fauna) present in riparian rainforested areas. Rainforest birds of Gondwanan origin present throughout remnant vegetation in the aquifer area. Relict taxa from Cretaceous angiosperm families present in all rainforest remnant areas. Plant taxa considered to occupy major nodal positions in the evolution of angiosperms are represented in most remnant rainforest areas.

Outstanding examples representing significant It is noted that much of the diversity has been lost owing to past clearing ongoing geological processes, biological evolution within the Mulgrave River aquifer sphere of influence. Approximately and mans interaction with his natural environment. 95% of all vegetation has been cleared within the project area sphere of influence by cane farming, and whilst diversity is still high, it is very low by comparison with the adjacent WHA.

Nevertheless, a high diversity of species is present within the project area, represented in a complex of remnant communities. The complexity is due to the mosaic of vegetation types and habitats represented, varying from sclerophyll, rainforest to mangrove remnant communities.

Area contains unique, rare or superlative natural The project area is bounded on either side by the WTQWHA, and the phenomena, formation or features of exceptional lower reaches of the Mulgrave River (in the WHA) represent an natural beauty. outstanding example of estuarine natural beauty.

Area contains the most important and significant A broad variety of habitats is represented in the study area, however habitats where threatened species of plants and owing to the generally low integrity of these habitats as a result of animals of outstanding universal value from the point clearing, important and significant habitats for species of of view of science and conservation still survive. conservation/scientific interest are limited to the tidal and near-tidal reaches of the Mulgrave River, outside the zone of influence of the impacts of the proposal.

3.5 Desktop and Database Assessments Data on attributes of the study area have been collated from various sources. This includes data obtained from web sites, database searches, digital and hardcopy mapping, various government agency

42/15610/99537 Mulgrave River Aquifer Feasibility Study 27 Public Environment Report sources and scientific literature. A review was completed of the available previous investigations, studies and reports. A general desktop database and spatial review was carried out on the documented environmental values of the area. This involved a review of relevant published information, particularly of known habitat of rare and threatened species. This review included:

 Searches of the Environmental Protection Agency’s (now the DERM) Queensland Herbarium database (HERBRECS) for plant species records.

 Specific searches of the Queensland Museum for recorded fauna species of conservation significance (Commonwealth EPBC Act listed and Queensland Nature Conservation Act listed species).

 Searches of the Environmental Protection Agency’s (now the DERM) Wildlife Online databases containing recorded wildlife sightings and listings of plants, fungi, protists, mammals, birds, reptiles, amphibians, freshwater fish, marine cartilaginous fish, and butterflies.

 Searches of the Commonwealth Department of Environment, Water, Heritage and the Arts (DEWHA) Protected Matters Search tool was undertaken. The Protected Matters Search Tool identifies matters of National Environmental Significance (NES) that may occur within the area or have habitats in the area of the site. These matters of NES are allocated varying conservation and management status under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).

 Analysis of the Regional Ecosystem Version 5.0 mapping and corresponding vegetation descriptions (Sattler and Williams 1999). The ecosystems mapped frequently contain a mixture of more than one vegetation type. Where this occurs, two or more RE labels are shown on the mapping with the most common vegetation community, the dominant one, being listed first and the other communities (subdominant) listed in order of their areal extent within the polygon. Note that Essential Habitat mapping for species is performed at 2.2 km around selected coordinates. The desktop data, combined with the specific assessment requirements of the PER data was collected from various sources including published data, available reports, and on line and external databases. A list of those species listed under the provisions of the Commonwealth EPBC Act as having habitat likely to occur in the area was assessed to determine the specific target habitat areas for the PER field surveys. Field surveys were designed to assess: a) whether the habitats as identified in the field were habitats likely to support the species of National Environmental Significance (NES) identified in the background data collation; b) the integrity of the habitats identified as suitable for these species (commenting only on those aspects that affect the integrity of the habitat: e.g. major weed invasion, pest species present); and c) any actual observations of the targeted species. Based on published and known habitat preferences for the species, distribution and range, and actual data records it was determined that it was unlikely that a number of the species identified in the PER Guidelines were present within the PER study area. However, potentially suitable habitat was examined to determine the likelihood of occurrence of these species.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 28 Public Environment Report 3.5.1 Fauna Field Surveys Surveys were undertaken across those ecosystems identified as groundwater dependent and that may be potentially affected by groundwater abstraction. This included riparian and instream communities, terrestrial communities on alluvium and on downstream wetland communities. Qualified botanists and ecologists undertook the surveys with the survey sites and areas stratified by habitat representation. All habitat and fauna surveys were in accordance with methodologies for assessment as outlined in the Australian Museum’s “The Provision of Data for National Fauna Survey Standards:” (DEH 2004) and as modified for site specific conditions. It should be noted that no field sampling for fish was undertaken. Those species of fish that are listed under the EPBC Act or NCA do not occur in the same biogeographical region as the aquifer, however suitable habitat for a number of endemic species considered uncommon is present in this area. Further details in regard to aquatic fauna are described in Section 5.7.

Reptiles and Amphibians The only large reptile that is water dependent and potentially vulnerable to impacts in the study area is the salt-water crocodile. This species is known to occur in the Mulgrave River and the presence of this species was confirmed through spotlighting undertaken by boat over a period of three nights along the reach of the Mulgrave River in the study area. It is not known to occur in the mid to upper sections of Behana Creek, but there are anecdotal sightings of crocodiles near the junction of Behana Creek with the Mulgrave River. The Commonwealth PER guidelines identified Litoria nannotis (torrent tree-frog) and Litoria rheocola (common mist-frog) as specific target species. Neither of these species are known to occur in the study area, although there is a sighting (not formally recorded) of L. nannotis near the study area boundary on upper Behana Creek. Surveys for both frog species were undertaken over a period of five nights and early evenings, in areas of upper Behana Creek, and two nights and early evenings in a section of the WHA on the mid reaches of the Mulgrave River. Surveys were conducted between February and April, during wet season conditions favourable to frogs. Surveys consisted of spotlighting and call playback over approximately a length of 1 km of Behana Creek (above the Bruce Highway), and on (un-named) tributary of the Mulgrave River within the WHA intersecting the river (refer to Appendix F for further information).

Birds The Commonwealth identified three birds of NES that may occur in the study area. These included the red goshawk, southern cassowary and Australian painted snipe. There are no confirmed records of the red goshawk within 200 km of the study area, and no habitat suitable for this species is present. It was therefore considered exceptionally unlikely that this species would be present in the highly agriculturally modified Mulgrave River Study Area. No red goshawks were observed in the area at the time of the field investigation. There are no records of the southern cassowary within the study area and any potentially suitable habitat has been reduced (as a result of clearing for agriculture) to isolated riparian pockets that form little to no connectivity with the WHA. Generally during targeted surveys for this species, the most obvious evidence of cassowary utilisation is the presence of large scats comprised predominantly of partially digested rainforest fruit. At the time of the field investigation, no cassowary scats or signs of the species was observed.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 29 Public Environment Report There are no formal records for cassowaries in the study area or areas immediately adjacent to the WHA bordering the Mulgrave River valley in the study area. The last confirmed cassowary sighting occurred over a decade ago in the lower reaches of the Mulgrave River near Mutchero Inlet during land clearing for sugar cane. The Australian painted snipe is a migratory species, likely to be transistory in the region for only a few days of each year within suitable wetland habitats. The species has not been recorded as occurring in this area due to a lack of suitable habitat such as wetlands. Extensive freshwater wetlands occur south at Eubanangee Swamp (Russell River), and tidal wetlands occur on the foreshore (ocean side) of the Mulgrave River estuary. There are a series of stranded lagoons (formed by changes owing to floods and deposition patterns) parallel to the Mulgrave River in the mid to lower sections of the study area (such as Tanners Lagoon). These are not true wetlands and essentially serve as the terminus to a number of modified creeks now serving as agricultural drains. The Australian painted snipe was not observed during the field investigations undertaken in the study area. For other birds a general log of sightings for potential species of conservation significance was kept during the field investigations to assess the ecological matters pertinent to the study area.

3.5.2 Flora Field Surveys The Commonwealth identified four species of flora within the PER guidelines. Whilst surveys were targeting these species in particular, records of other species of significance were also undertaken concurrently. Flora surveys were in accordance with the guidelines produced by the Qld Herbarium, Methodology for Survey and Mapping of Regional Ecosystem and Vegetation Communities in Queensland (Neldner et al. 2005, version 3.1). Public access to some areas was problematic as permission was not able to be obtained from some landowners. However representative areas of all known habitat types were surveyed using a combination of boat access, public road and esplanade reserve where landholder access was granted in many areas. Flora surveys consisted of a series of transects through riparian vegetation parallel to the banks of the Mulgrave River and Behana Creek. Flora transects were stratified on the basis of the conservation status of the vegetation community present, the potential vulnerability of the vegetation community to groundwater stresses, and potential as likely habitat to species of conservation significance. More emphasis was placed on establishing transects in vegetation meeting these criteria than in other areas (e.g. open grasslands on edge of canefields). The purpose of the flora surveys were not to list all possible flora species that occurred in these transects but to:

 Identify if any particular species of conservation interest were present;

 Determine the general integrity and status of vegetation communities considered to be groundwater dependent; and

 Assess the general vulnerability of groundwater communities to abstraction.

3.6 Environmental Flows Assessment The Benchmarking Methodology developed in Queensland is based upon the use of biophysical ‘reference’ and impact of ‘benchmark’ sites, flow-ecological response models and risk assessment

42/15610/99537 Mulgrave River Aquifer Feasibility Study 30 Public Environment Report procedures. In essence, it seeks to address the question “How much water does a river need, or how much can we change a river’s flow regime before the aquatic ecosystem becomes degraded?” Benchmarking is a method for estimating basin-wide environmental water requirements needed to maintain, preserve and/or enhance river ecosystems to a level that has been determined to be desirable by the community, government departments, and other interested parties. Within the context of the Council of Australian Government’s (CoAG) Water Reform Framework, and the resultant Queensland Water Act (2000), aquatic ecosystems are now seen as a legitimate ‘users’ of water (see ARMCANZ, ANZECC 1996). The protection and restoration of river flow regimes is a key element of the water reforms and the Queensland Water Act 2000. Crucially, the Benchmarking Methodology helps water planners and managers to assess and minimise the risk of ecological impacts that may be caused by water resource developments. For this initial assessment, analysis of hydrological flows was undertaken utilising data provided by DERM for gauging stations located on the Mulgrave River and Behana Creek. Data was provided for five gauging stations however the gauging station closest to the main aquifer area is located at Gordonvale, which is upstream of main aquifer interface with the Mulgrave River. The data set for the Gordonvale gauging station extends as far back as 1916. DERM have identified that low flows recorded at the Gordonvale gauging station may be questionable, as during low flow periods the flow bypasses the gauging station intake which is located within the Mulgrave Mill pump house. Low flows are therefore likely to be under-estimated by the Gordonvale gauge. The Behana Creek gauging station has only limited data, and has ceased operating. Therefore, in total, there are limited resources available to establish a definitive flow assessment. Given the scale of the abstractions relative to the river flows, the methodologies in this PER are considered sufficient to assess the potential adverse impacts and principles required to be adopted in the Borefield Operating Rules to protect environmental values.

3.7 Bore Testing and Modelling Verification

3.7.1 Selection of Preferred Borefield Investigation Areas Bore lithologic information indicates the generally sandy nature of sediments in the Mulgrave River valley and in particular the fan deposits flanking the valley margins. The Mulgrave River has down cut the fan material to form a trench that has been backfilled with a larger proportion of clayey material than in the fan sediments. The current Mulgrave River floodplain is at a lower elevation than the surrounding fan and colluvial deposits on the flanks of the ranges. Groundwater recharge rates outside the Mulgrave River trench appear likely to be higher due to the generally sandier sediments, particularly at shallow depth. The later Quaternary sediments associated with the current river provide confining conditions to the underlying early Quaternary and fan/colluvial sediments. South of the groundwater divide and along the valley margins, groundwater levels are above the Mulgrave River, with some areas showing significant seasonal response to rainfall recharge. Groundwater flow from these areas is to the Mulgrave River or lower reaches of Behana Creek. A review of groundwater quality analysis indicates that groundwater is generally potable, with low salinity levels and generally low concentrations of other characteristics such as iron and manganese. An analysis of bore hydrographs indicates that groundwater levels respond rapidly to seasonal rainfall and the annual rainfall is in excess of the aquifer storage capacity. It is only after several well-below-

42/15610/99537 Mulgrave River Aquifer Feasibility Study 31 Public Environment Report average rainfall years that groundwater level recovery is affected. This suggests that there is sufficient annual recharge potential to allow recovery in groundwater levels following increased groundwater extraction. Based on aquifer lithology and groundwater recharge, potential sites for further investigation and testing are:

 Areas of sandy vertical profile where seasonal recharge from rainfall appears significant.

 Areas where runoff from the ranges or infiltration from smaller streams occurs.

 Areas with significant aquifer thickness at depth to maximise bore yields.

 Areas within the valley where a thick section of aquifer is overlain by semi-confining or confining units that may restrict interconnection with surface waters. Figure 2 indicates four sections of the Mulgrave River valley where aquifer conditions were considered suitable for groundwater supply development. Test Area 1 is on the fan deposits where a generally sandy profile occurs and annual rainfall recharge provides significant rises in groundwater levels. Areas 2 and 3 are along the flanks of the valley where sandy colluvial and fan sediments have been deposited and recharge from Behana Creek and runoff from the ranges seasonally influences groundwater levels. Area 4 is located at the deepest section of the valley where over 20 m of possibly Tertiary age sand has been intersected above bedrock at 95 m depth, overlain by confining sandy clays and clays. Investigations required the drilling and testing of bores within each area to determine aquifer response to pumping and the potential sustainable yield in the long term. Test sites were designed to comprise a pump bore and several observation bores at various depths to monitor lateral and vertical response of the aquifer to pump drawdown. To adequately determine the potential interaction between surface water and the aquifer, a monitoring network of bores and stream gauging stations were established at several sites. Regular monitoring assisted in assessing the loss of surface water to the aquifer in the wet season and discharge of groundwater to the streams in the dry season. This information is a critical component of the aquifer water balance and in assessing the potential impacts of long term pumping on surface waters and the environment.

3.7.2 Modelling Approach and Background The hydrogeological review of the Mulgrave River area identified the Quaternary alluvium as having the highest potential for groundwater development. It has the highest potential yield, and contains potable quality groundwater. Investigation bores were drilled into four areas between Gordonvale and Aloomba, and aquifer testing was undertaken. Data from field investigations and existing sources were collated and analysed to construct a Hydrogeological Conceptual Model, including the construction of a three-dimensional geological model, hydrogeological mapping, assessment of groundwater / surface water interaction, analysis of potential groundwater recharge rates, and construction of preliminary catchment water balances.

The Hydrogeological Conceptual Model was used to construct a numerical groundwater flow model using MODFLOW (Harbaugh et al. 2000). Recharge input to the groundwater flow model was calculated using the cropping and soil-moisture model PERFECT (Littleboy et al. 1989), and input to the MODFLOW

42/15610/99537 Mulgrave River Aquifer Feasibility Study 32 Public Environment Report model. PEST (Doherty, 1999) and manual methods were used to calibrate the model in steady state and transient modes to recorded observations of historical groundwater levels. The calibration quality is considered sufficient for the purposes of the investigation given the quality and spatial and temporal resolution of the available data. However in recognition of the model limitations, uncertainty and sensitivity analysis has been used to indicate the uncertainty in model predictions.

3.7.3 Caveats and Assumptions used in Modelling Following is a summary of the identified limitations of the numerical model developed in this modelling investigation, and its associated consequences:

 Lack of calibration to river base flow due to a lack of sufficient gauged river data against which to calibrate. This results in uncertainty in the degree of river – aquifer interaction in the model, and has the flow-on effect of uncertainty in model predictions of drawdown and induced river leakage into the aquifer. However, this uncertainty is minimised via sensitivity analysis, and confidence in model predictions is not considered to significantly affected by the remaining uncertainty;

 Lack of data on river and creek stage heights in the lower parts of the catchment. This would cause a minor impact on the quality of the model calibration in the lower catchment. However, it is not considered to significantly affect model predictions;

 Lack of recorded groundwater usage data. In this modelling investigation, the entire allocated volume has been modelled, which means that existing groundwater abstraction is overestimated in the model, but groundwater usage is a small component of the water balance, and therefore results are insensitive to this;

 Groundwater observation data is concentrated around the main groundwater abstraction / irrigation area north of Gordonvale. This results in a model that is better-constrained in this area than in others, particularly the far north and south of the Mulgrave River Alluvium;

 The existing groundwater observation data is not of sufficient temporal resolution to identify the timing and magnitude of seasonal peaks in groundwater recharge. This compromises the quality of the calibration, particularly for wetter than average climatic years; and

 The model does not incorporate runoff-recharge events from the bedrock outcrop bordering the east and west valley sides. The water balance assessments undertaken suggest that the major components of the water balance have been accounted for, and therefore lack of representation of this process does not compromise the modelling outcomes. At the time the model was derived there was also no information on the potential demand on the aquifer, and the operational requirements were unknown. The model was therefore run on the assumption that the borefield would abstract the maximum allocations (15 ML/day) each day for the full year. In consideration of now known draft operational requirements it is in fact unlikely that the borefield would be used during the wet season period January to March (three months) and that at other times abstraction from the aquifer would be in response to daily demand, which in most instances, would equate to the maximum abstraction only being required for a limited number of days each week. Currently Cairns Regional Council Water and Waste has committed to further studies on the aquifer, and the inclusion of the revised operational aspects of the borefield and demand requirements will refine the existing groundwater model. These studies will improve the understanding of the surface water and groundwater interaction to allow better definition of the Borefield Operating Rules.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 33 Public Environment Report 3.8 Derivation of Risk Assessment Methodologies

3.8.1 Environmental Risk and Likely Impact Approach The impact and risk assessment was undertaken using an Environmental Risk and Likely Impact (“ERLI”) approach. For each possible impact aspect, two key areas were addressed: 1. Environmental Risk

This essentially considers the risk of irreversible change to natural ecological processes and community interaction. Assessment will address;

 conservation significance of environmental, social and cultural values and regional context of these values;

 current level of integrity of natural ecosystem processes;

 known sensitivity of ecosystem processes/natural values to human induced change;

 natural change and resilience of relevant ecosystem processes/natural values;

 potential for cumulative social and environmental impacts; and

 level of scientific certainty of the above factors. 2. Likely Impact This considered the likely impact of the abstraction, as modified and undertaken in accordance with mitigation strategies (including any environmental management plans or conditions from licensing/approval agencies) and include:

 geographic extent of the activities;

 duration of the activity;

 magnitude of potential environmental and social change;

 confidence in prediction of impact;

 confidence in mitigation strategies to minimise ecological and social risks; and

 ability to monitor the impacts and detect change before irreversible change to system processes. The approach above considers direct and indirect impacts, short and long term, cumulative, temporary and irreversible, and adverse and beneficial impacts. The significance of the impacts was placed in an appropriate context in which to justifiably determine the impact’s significance. In particular, the duration of the impact (temporary v permanent) and reversibility were considered. The ability of natural systems (including population, communities and ecosystems) to accept or assimilate impacts were also addressed. The above approach is used to provide the essential information that is used in the formal Risk Assessment as based on the Australian/New Zealand Standard 4360:1999. This methodology is outlined below.

Formal Risk Assessment The ERLI approach will be used to justify the Risk Assessment rankings as based on AS/NZS 4360:1999. This Standard forms the basis of risk assessment for many government agencies, and

42/15610/99537 Mulgrave River Aquifer Feasibility Study 34 Public Environment Report provides a transparent approach to ranking the relative risks and impacts of the proposal on each of the elements identified. A number of stages were used in the risk assessment and these are outlined below:

Stage 1: Identification of Risk This includes identification of all relevant risks, addresses all known activities and related environmental aspects of the project.

Stage 2: Risk Analysis

 An important feature is recognition of the fact that an event’s consequence extends beyond the immediate impact. This methodology ensures that the full consequences of events are visible to risk owners and managers and that the effects on the project are all understood and treated. Each class of consequence is rated a score of 0 - 5, where “0” is nil consequence to “5” is catastrophic.

 An analysis of each risk is undertaken to determine an environmental event’s likelihood of occurrence and its consequences. A five-level qualitative description of the likelihood and consequences for each risk enables a semi-quantitative method to be used to calculate a ‘score’ for each risk. Definitions and scales for Consequences are shown in Table 6 and definitions and scales for Likelihood are shown in Table 7.

Stage 3: Calculation of Risk Level Two levels of risk are used: The Primary Risk Level (PRL) is a conservative measure of risk, based on the most severe consequences across all the relevant criteria. PRL is calculated according to the equation: Primary Risk Level (PRL) = Likelihood Rating X Maximum Consequence Rating

The Secondary Risk Level (SRL) is a less conservative measure of risk, which incorporates all relevant criteria, not just the most severe ones. SRL is calculated according to the equation: Secondary Risk Level (SRL) = Likelihood Rating X Average Consequence Rating

In most circumstances PRL should be the preferred measure, as it is more conservative. Risk scores are banded into risk levels which provide a ‘plain English’ view of the risk. Scores will always be visible to enable prioritisation within bands. Table 8 shows the bands, their threshold values and indicative management action.

Table 6: Threat Criteria and Consequent Scales

Rating Project Delivery Environment Community & Sustainability Financial Impacts

All activities cease. No Long-term Significant, extensive, detrimental Extreme resumption for at least 12 environmental harm. long-term impacts on the community or financial loss to months. Major unacceptable Permanent irreparable public health. Irreparable damage to remedy. delays in delivery of damage is caused to the highly valued structures or locations of

5 capability occurring at critical environment. For cultural significance or sacred value. times. Unable to conduct example, acid Permanent and significant loss of scarce environmental resources. Catastrophic missions. Failure to achieve contamination of critical performance goals. Centenary Lakes and closure to public.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 35 Public Environment Report Rating Project Delivery Environment Community & Sustainability Financial Impacts

All normal activities curtailed. Significant Significant detrimental impacts on the Major financial No resumption of normal environmental damage community. Major damage to highly loss to remedy. activities for between 6 and with widespread valued structures or locations of 12 months. Major delays of impacts. Damage may cultural significance or sacred value.

4 capability delivery but at non- be permanent. Significant loss of scarce Major critical times. Unable to environmental resources. conduct missions. Failure to achieve some performance targets.

Most activities affected. No Moderate violation of Detrimental impacts on the community Moderate resumption of normal regulation or guideline or public health. Damage to valued financial loss to activities for up to 6 months. with moderate damage structures or locations of cultural remedy. 3 Significant delays resulting in to the environment and significance or sacred value. Loss of

Moderate some reduction in significant clean-up cost. scarce environmental resources. performance.

Modification to planned Minor violation of Minor impact on the community or Minor financial activities can be expected. regulation or guideline public health. Minor damage to valued loss to remedy. Minor delays. Minor with minimal damage to structures or locations of cultural

2 performance degradation. the environment and significance or sacred value. Minor

Minor small clean up. loss of environmental resources. Immediately contained on-site.

Some minor modification to Negligible release or Negligible social impact. Negligible Insignificant planned activities may be damage that is damage to valued structures or financial loss to necessary. Insignificant contained on-site and is locations of cultural significance or remedy. delays. Negligible non-reportable. The sacred value. Negligible loss of 1 performance impact. damage is fully environmental resources. recoverable with no Insignificant permanent impact on the environment.

No impact on schedules. No environmental No social impact, damage to valued No cost impact. impact. structures or locations of cultural 0

Nil significance or sacred value or loss of environmental resources.

Table 7: Likelihood Rating

LIKELIHOOD Rating The potential for risks to occur and lead to the assessed consequences

5 Almost Very high, may occur at Probability over A similar outcome has arisen several times certain least several times per year 0.8 per year in the same location, operation or activity

4 Likely High, may arise about once Probability 0.5 - A similar outcome has arisen several times per year 0.8 per year for Cairns Regional Council

3 Possible Possible, may arise about Probability 0.1 - A similar outcome has arisen at some time once in a one to ten year 0.5 previously for Cairns Regional Council period

2 Unlikely Not impossible, likely to Probability 0.04 - A similar outcome has arisen at some time occur during the next ten to 0.1 previously in Cairns Regional Council but twenty-five years action has been taken to reduce the chance of recurrence.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 36 Public Environment Report LIKELIHOOD Rating The potential for risks to occur and lead to the assessed consequences

1 Rare Very low, very unlikely Probability less A similar outcome has arisen on a regional, during the next twenty-five than 0.04 state, national or international level and not years unique to Cairns Regional Council.

Table 8: Risk Levels and Management Action (example)

Risk Level Descriptor Indicative management action (PRL or SRL)

16-25 Extreme Immediate action required, senior management will be involved

9-15.9 High Senior management attention needed and management responsibilities specified for further action

4-8.9 Medium Manage by specific monitoring or response procedures, develop more detailed actions as resources allow

1-3.9 Low Manage by routine procedures, unlikely to need specific application of resources

Stage 4: Determination of Options for Mitigation of Risk Following the analysis of a risk it is necessary to investigate the options available for mitigation treatment and then determine the option, or options, that provide the greatest cost benefit. Risks may be treated in one or a combination of ways6:

 Avoiding a risk by preventing the activity that leads to the risk eventuating.

 Reducing the likelihood of the risk eventuating.

 Reducing the consequences if the risk does eventuate.

 Transfer the risk.

 Retaining the risk.

3.9 Stakeholder and Community Engagement

3.9.1 Landholder Engagement Stakeholder and community engagement has been undertaken throughout the course of these studies over approximately 16 months. The Mulgrave River aquifer is located in a rural/agricultural area and intensely farmed predominately with sugar cane. The town of Gordonvale and the settlements of Aloomba, Deeral and Fishery Falls are located within the aquifer area and service the sugar cane industry. Initially, all landholders with registered bores were contacted by Cairns Regional Council Water and Waste, seeking permission to access bores on private properties for monitoring and testing purposes. There were 66 landholders contacted by letter, telephone and personal representation inviting comment on the proposal and asking for assistance with the study. In preparing the risk assessment that

6 After AS/NZS 4360:2004

42/15610/99537 Mulgrave River Aquifer Feasibility Study 37 Public Environment Report comprises part of this PER (and for the technical feasibility study), available socio/economic information, in combination with discussions with indigenous representatives (via Aboriginal Rainforest Council project officers) and potentially affected landholders was used to provide a risk assessment framework. Following landholder consultation, a water quality-monitoring program was prepared which included the testing of surface water and groundwater in existing registered bores (with consent of land owners) and test bores. The final test bore sites were negotiated with adjacent landowners and test production bores were established over a five week period prior to Christmas 2006. Project updates were regularly supplied to the relevant Council committee of the former Cairns City Council via monthly update. These updates were then relayed by representative local government members to the generally interested public and media outlets. Results of test bores and subsequent accumulation of groundwater information, numerical modelling and predicted likely impacts were conveyed to a technical working group workshop comprising the lead concurrence and referral statutory authorities for the project in March 2007. Technical advice and information on the studies was regularly communicated between various officers and staff members of the various technical agencies throughout the course of the project.

Table 9: Details of Stakeholders Consulted

Stakeholder Nature of Consultation Responses and Views

Landholders within 66 landholders with registered bores were 14 landholders responded to the initial consultation, allowing project area. contacted by mail by Cairns Regional Council access to existing bores. One landholder advised the bore Water and Waste in relation to the usage of their had been decommissioned. Two landholders expressed bores and access to monitoring of their bores. concern via telephone conversations over possible availability of future water supply for irrigation purposes. Other landholders had no specific comments related to the project.

Landholders Four landholders were consulted in relation to the All four landholders allowed permission for water from the affected by test establishment of test bores and associated pump 100 pump tests to run off over their cane land. One bores and pump testing on road reserves adjacent their properties. landholder requested the position of the drill rig to be altered testing to allow easier access for cane harvesting machinery.

Wet Tropics Representatives from WTMA on Technical Initial project inception meeting raised concerns about Management Working Group. impacts on downstream WHA values in Mutchero Inlet and Authority (WTMA) groundwater lowering on acid sulfate soils and potential salinisation. Information from modelling was provided at workshop panel convened in March 2007. WTMA have since indicated verbally no further concerns.

Department of Representatives from DERM on Technical Working DERM consulted throughout life of project and provided Environment and Group. groundwater and hydrogeological data, including access to Resource the DERM Queensland Groundwater database. DERM Management requested figures on groundwater abstraction scenarios and (former DNRW) modelling results.

Great Barrier Reef Representatives from GBRMPA on Technical GBRMPA attended workshop panel in March 2007. Initial Marine Park Working Group. concerns related to availability of freshwater flows into Great Authority (GBRMPA) Barrier Reef Marine Park, and potential for acid sulfate soil exposure. Results from modelling indicated no impacts from abstraction (of either Stage 1 and 2) would affect these attributes. No further comment supplied by GBRMPA.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 38 Public Environment Report Stakeholder Nature of Consultation Responses and Views

Department of Representatives from DERM on Technical Working DERM indicated will reserve comment on issues until Environment and Group. CRCWW submit development applications for approval. Resource Based on information presented at workshop, believe that all Management potential effects have been addressed. (former EPA)

Department of Representatives from DEEDI on Technical Concerns raised over potential impacts on environmental Employment, Working Group. flows of the Mulgrave River, water quality, acid sulfate soil Economic generation and impacts on community fisheries. Indicated Development and will review information submitted for development Innovation (former applications for the project, but that modelling information DPI&F) presented to agency indicated no potential impacts.

3.9.2 Technical Agency Consultation A technical working group had been convened during the course of the studies. The aim of the technical reference group was to ensure that all appropriate information necessary to assess the feasibility of the project had been gathered. The technical working group consisted of the lead concurrence and referral statutory authorities and comprised the Department of Natural Resources and Water (now DERM), Environmental Protection Agency (now DERM), Great Barrier Reef Marine Park Authority, Wet Tropics Management Authority, Department of Primary Industries (now DEEDI) and Cairns Regional Council Water and Waste. Formal meetings have been held with agency representatives at different stages of the PER development. Agency representatives who were not able to attend were provided with updates on the progress of the PER. All agencies have had comment and ability to engage in the project. A result of the test bores and subsequent accumulation of groundwater information, numerical modelling, environmental studies and predicted likely impacts were conveyed to a technical working group in March 2007. Technical advice and information on the studies was regularly communicated between various officers and staff members of the various technical agencies throughout the course of the project.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 39 Public Environment Report 4. Description of the Environment – Physical Aspects

4.1 Information Sources The information in the following section has been summarised and adapted from the hydrological investigations undertaken for the Aquifer Feasibility Study (GHD 2007). Only those elements of the technical report as relevant to the guidelines of the PER have been included in the section following. The primary task of the hydrogeological assessment was to review existing available data and make recommendations as to suitable locations for establishment of bores for pump test purposes. Geological data is available from the Innisfail geological map (de Keyser et al. 1964). Initial hydrogeological work in the area commenced in 1973 with investigation drilling and testing of the floodplain area to determine groundwater supply potential (Muller, 1975). A number of observation bores were installed and these form the majority of the current monitoring network. Several aquifer tests were completed to determine aquifer parameters and a geophysical survey (seismic refraction and resistivity) was completed in 1973 (Searle and Huber, 1973). Reports from the testing and geophysical survey are not currently available. Subsequent work by the then Queensland Department of Natural Resources (DNR, 1988) and others assessed the potential yield of the aquifer utilising a groundwater numerical model. The DNR (now DERM) groundwater database provides records on private and government investigation bores. A project dataset of all bores in the study area was extracted from the database and used to define lithology, water quality and groundwater levels. Soils information comes from Murtha et al. 1996 and has been used to define soil characteristics and potential groundwater recharge areas. Information on availability of reports for the early investigation work was provided by Mr Graham Herbert and Mr Bill Huxley (Department of Natural Resources, Mines and Water, (NRM&W, now DERM)).

4.2 Climate The study area is within the ‘tropical’ climate zone as defined by the Kôppen classification. This zone is characterised by major seasonal rainfall with a marked wet summer and warm, dry winter. Within Queensland’s well-known Wet Tropics, this area has the highest rainfall averages in Australia with an average yearly rainfall of 3200 mm. Tropical latitude, coastal position and high mountains bordering the alluvial plains, are dominating factors in the Mulgrave catchment (Bureau of Meteorology (BOM) website). Tropical thunderstorms develop frequently along the ranges near Gordonvale but seldom move off and over the populated areas. Prevailing winds are generally east to southeasterly and the strongest winds occur during the monsoon season (excluding cyclones).

4.2.1 Temperature and Humidity Temperatures are quite uniform throughout the year with typical daytime minimum/maximum in mid summer ranging between 23 and 31°C and 18 to 26°C in mid winter. Occasional cold snaps occur overnight in the winter months but these rarely fall below 14°C in the catchment valley.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 40 Public Environment Report Relative humidity values are typically high for the region reaching an average of 79% during the months of February to March, and 68-70% during the cooler months, but may reach into the 90’s quite regularly (BOM website).

4.2.2 Rainfall The Mulgrave River catchment is one of the highest rainfall areas of Australia. Long-term average annual (LTA) rainfall on the valley floor ranges from as high as 3800 mm near Mutchero Inlet in the south, to 2000 mm in the area extending from Gordonvale northwards to Cairns and Trinity Inlet. This rainfall is highly seasonal, with distinct wet (January to May) and dry (August to December) seasons. The mean annual evaporation does not vary significantly across the area, with an annual mean of 2251 mm measured at Gordonvale. Cyclones typically develop between January and April, resulting in heavy rainfall. Four to six tropical cyclones are formed in the Coral Sea each year and an average of two cross the coast in any given year. These systems exert a strong influence on rainfall variability in the region due to their unpredictability. For example, during the 2006 wet season, the far north had experienced well above average rainfall records. This was due to continued monsoonal activities through April 2006 with Severe Tropical Cyclone Monica increasing monthly rainfall totals for the study area by greater than three times the average. Additionally, Severe Tropical Cyclone Larry crossed the coast near Innisfail on the 20th March 2006. This cyclone was a Category 5 and the first of this magnitude to cross the coast since 1918, also at the same geographical location. Conversely, in 2002, Cairns recorded its lowest rainfall since records began in 1882. El Nino and La Nina have a strong impact on the wet tropics system and influence rainfall. Generally, the region is getting progressively drier with lower rainfall averages due to the significant increase in El Nino events (Weston and Goosem, 2004). Planning for urban water supplies in dry years has now become a reality for historically deemed wetter areas in Australia.

4.3 Topography The Mulgrave River valley is located on a narrow alluvial plain. It forms a flat to undulating floodplain, with river terraces east and south of Gordonvale at 23 m, 9 m and 6 m above the present river level (Muller, 1975). In the west and east of the floodplain lie the rugged terrains of the Bellenden Ker and Malbon Thompson Ranges, respectively. These granitic ranges have been deeply incised to form steep sided ranges falling abruptly to the floodplain. The Bellenden Ker Range to the west of the plain rises to 1592 m at Mount Bellenden Ker Central Peak and 1622 m at Mount Bartle Frere further south. The Malbon Thompson Range rises to 1026 m at Bell Peak North in the east. To the northwest of Gordonvale, metamorphic rocks form more subdued ranges rising to 1098 m. Green Hill, approximately 6 km northeast of Gordonvale, is a volcanic feature rising to 131 m elevation. To the south of the Mulgrave River, the Russell River has a similar morphology. Topography and surface water features of the Mulgrave River Aquifer Area are shown in the following figure (Figure 6).

42/15610/99537 Mulgrave River Aquifer Feasibility Study 41 Public Environment Report Figure 6: Topography and Surface Drainage Features

42/15610/99537 Mulgrave River Aquifer Feasibility Study 42 Public Environment Report 4.4 Surface Drainage Features

4.4.1 Surface Hydrology The Mulgrave River is one of the major coastal rivers in North Queensland. Covering an area of approximately 810 km2 and with a mean annual discharge of 770,000 ML, the Mulgrave River catchment has one of the highest areas of mean annual runoff of any Australian catchment. The headwaters are in the ranges to the west of the coastal floodplain, which the river enters at Gordonvale, meandering easterly then southerly across the floodplain to Mutchero Inlet. River flows are highly seasonal; the mean total flow in the dry season is around 161,000 ML (or ~14% of mean total annual discharge), and 849,797 ML (75% of mean total annual discharge) during the wet season. The remaining 11% of total flow occurs in the period of June-July. The deeply incised ranges to the east and west of the floodplain generate the headwaters of a number of streams that form tributaries to the Mulgrave River. Behana Creek is the largest tributary on the western side of the floodplain. A number of smaller streams flow from the ranges to the east, the other more significant streams being Fishery and Figtree Creeks. All the creeks carry significant flows during the wet season, but during the drier months may be reduced to intermittent flows dependent on rainfall events in the upper catchment. River terraces on the floodplain east of Gordonvale form a surface water divide, with the main surface water drainage heading from the divide north to Trinity Inlet, and on the southern side entering into the Mulgrave River and hence into Mutchero Inlet. Mutchero Inlet is at the junction of the Mulgrave River (from the north), and the Russell River (from the south).

4.4.2 Stream Condition The clearing of land for sugar cane cultivation has extended to the top of the river banks and has resulted in bank erosion and silting of the river as streams become wider and shallower (Connell Wagner, 1992). Local Landcare groups have undertaken limited revegetation of the riverbanks in some areas. Riparian vegetation, however is generally fragmented, impacted by varying historical and ongoing land usages, and is discontinuous along the waterways in the study area. Sand and gravel has been extracted from the bed of the Mulgrave River and Behana Creek, resulting in pools several metres deep in areas previously shallow in the dry season.

4.5 Soils Soils have been divided into four broad classifications based on origin and location – schist soils, granite soils, volcanic soils and alluvial soils (Muller, 1975). Parent material influence is most pronounced on the floodplain margins. Where soils originate from granitic areas they are coarse textured and dominantly sandy, uniform or gradationally textured; while those that develop from metamorphic areas are fine textured and predominantly clayey (Willmott and Stephenson, 1989). On the floodplain soils range from little-developed uniform textured fine sandy soils on the younger terraces and levees, to strongly structured uniform or gradational soils on well drained alluvium and clays on poorly drained areas (Willmott and Stephenson, 1989). The alluvial flats forming the floodplain of the Mulgrave and Little Mulgrave Rivers consist mostly of brown sandy loam. The gravel and sand in the riverbeds are of a mixed origin. On the alluvial flats north

42/15610/99537 Mulgrave River Aquifer Feasibility Study 43 Public Environment Report of the Mulgrave River and extending to Trinity Inlet, the soil is a brown loam underlain by light brown sandy loam. To the south the alluvial soil extending from Aloomba to the Mt Sophia / Fishery Falls area is essentially grey-brown clayey loam and silty loam. In the Aloomba area there is a complex admixture of alluvial, schist and granite soils. A swampy area to the east of Deeral has been drained to allow sugar cane cultivation (Connell Wagner 1992). The volcanic soil at Green Hill and along the Mulgrave and Little Mulgrave Rivers is typically a red clayey loam about 0.45 m thick underlain by red clay. The soil contains weathered basalt fragments. On the granitic slopes of the adjacent ranges grey sandy clay is usually present, however in places a red residual granitic soil occurs. In several areas on the flats adjacent to Walsh’s Pyramid, black sand and clayey loam including highly weathered granite fragments are found. The soils in the study area can be broadly subdivided based on origin (Murtha 1996) as shown in Table 10. The vertical hydraulic conductivity for each soil division was used for groundwater modelling purposes (see Appendix D).

Table 10: Soil Type and Vertical Conductivity (from DNR, 1999)

CAPILLARY GRAVITY STORE VERTICAL HYDRAULIC SOIL TYPE STORE (mm) (mm) CONDUCTIVITY (mm/d)

Well drained soils formed on the alluvium, 160 20 30

Poorly drained soils formed on the alluvium, 190 15 5

Soils of granitic origin, 150 20 15

Soils of metamorphic origin, 150 40 15

Soils of basic rock origin, and 150 40 15

Soils of the swamp and tidal zone. 190 15 5

Note the column headings are clarified below:

 Capillary Store in mm is expressed as the equivalent depth of water that would be contained within a 1 cubic metre block of soil prior to the block being unable to accept more water.

 Gravity Store in mm is the equivalent depth of water that remains once the same block referred to above has been "drained" under gravity forces alone.

 The difference between the capillary store and the gravity store is the volume of water expected to drain under gravity forces alone from a saturated cubic metre block of soil.

 Vertical Hydraulic Conductivity is the rate at which water acting under gravity forces will move through a soil. Soil information from the CSIRO Enhanced Soils Information for Sugar Lands project (Soils of the Babinda-Cairns Area, 1996) is shown in Figure 7 with the broad soil associations and acid sulfate soils in Figure 8. The label descriptions for these maps are in Table 11.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 44 Public Environment Report Table 11: CSIRO Description of Soils in the study area

Label - Description Label - Description

Bb - Black acid peat (organic) Lu - Grey sandy loam

Bc - Brown clay loam M1 - Mountainous reddish brown non-cracking clay loam

Bg - Grey brown non-cracking clay loam M2 - Mountainous brown clay loam

Bi - Brown sandy loam Mb - Brown sandy clay loam

Cl - Grey brown sandy clay loam (structured yellow Mg - Mangrove intertidal saline soils earth)

Cn - Brown fine sandy loam Mm - Dark clay loam

Co - Brownish grey light non-cracking clay Ms - Reddish brown sandy clay loam

Et - Greyish brown clay loam Pg - Reddish brown clay loam

Ga - Reddish brown non-cracking clay loam Pr - Grey sandy clay loam

He - Yellow/yellow-grey loam Ra - Brown light non-cracking clay

Hu - Pale to black coarse sand Si - Greyish brown sandy clay loam

Il - Greyish brown light clay Sl - Sandy clay loam (structured red earth)

In - Brown non-cracking clay Th - Yellow brown sandy loam

Jp - Stratified coarse sand and gravel with boulders Ti - Brown light to medium non-cracking clay

Jr - Greyish brown loam Tu - Brown silty loam to silty clay loam

Ki - Yellowish medium non-cracking clay Ty - Reddish brown sandy non-cracking clay loam

Km - Black loam to clay loam Ut - Reddish brown clay loam or light clay

Li - Brown silty loam Vi - Brown loam or sandy loam

4.5.1 Acid Sulfate Soils Acid sulfate soils are predominantly soils associated with areas of Quaternary alluvium with high levels of organic matter and sulphidic material present. In the majority of cases (though not all) these areas are typically found in swampy and tidally influenced areas where mangroves are present. Acid and toxic concentrations of metals can be released into the environment when acid sulfate soils are exposed to air and become oxidised. The Queensland Department of Environment and Resource Management and Queensland Acid Sulfate Soil Investigation Team (QASSIT) have mapped the likely occurrence of potential acid soils (PASS) throughout coastal Queensland. They have mapped the lower section of the Mulgrave River as being potential acid sulfate soil (PASS). These soils are in areas dominated by mangrove and melaleuca wetlands, and in most instances are tidally influenced. Acid sulfate problems exist for some farmers about Mutchero Inlet where vegetation clearing and ground tilling (for sugar cane) has resulted in the generation of actual acid sulfate conditions and subsequent loss in agricultural productivity. The general areas mapped as PASS by DERM and QASSIT approximate the extent of mangrove intertidal saline soils (refer to Map Unit Mg in Figure 7 and Table 11).

42/15610/99537 Mulgrave River Aquifer Feasibility Study 45 Public Environment Report There are two distinct conditions associated with acid sulfate soils in the Mulgrave River area (refer to Figure 8). The first condition is that most typically found in the Cairns area. That is, acid sulfate soils are generally found below 5 m Australian Height Datum (AHD) and in Holocene sediments (organic-rich sediments and silts). They are usually associated with coastal lowlands and estuarine flood plains, they contain pyrites and sulfides. Typically the areas around (and within) any of the mangrove/tidally influenced areas (lower reaches of the Mulgrave River) should be considered to contain acid sulfate soils. Under natural conditions acid sulfate soils are usually located below the watertable. When these low-lying areas are exposed through dewatering, excavated or drained, there is potential for the acceleration of soil oxidation (of the pyrites) and subsequent acid leachate generation. The second condition is that of naturally occurring acid soil conditions, where the acidity is generated as a result of organic acids. It should be noted that organic acids (e.g. humic/tannic acids generated in Melaleuca swamps) are a common feature of tropical coastal ecosystems. These organic acids can produce acid water and sediments with the pH of these usually around 4.5 - 5.5. These sediments do not have the ability to generate additional acid when exposed to air and therefore do not pose the same risk as potential or actual acid sulfate soils (PASS and AASS generated from exposure of acid sulfate soils). The lower reaches of the Mulgrave River occur in a coastal environment with expansive areas of Melaleuca swamps capable of leaching organic acids and subsequently producing acid soil conditions. Cane farming in the lower Russell/Mulgrave River reaches, in the area about Mutchero Inlet, has exposed both types of acid sulfate soil conditions. Extensive areas of tea tree swamp has been cleared for farming, and subsequent excavation for drainage works has exposed acid sulfate soils. Consequently, this has resulted in the oxidation of PASS and the generation of acid runoff which has adversely affected productivity in these areas.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 46 Public Environment Report Figure 7: CSIRO Soil Mapping Units

42/15610/99537 Mulgrave River Aquifer Feasibility Study 47 Public Environment Report Figure 8: Soil Associations and Potential Acid Sulfate Soils Areas

4.6 Geology The major stratigraphic units of the region are described in Muller (1975) and summarised in Table 12. Broadly, the four major geologic units are the Barron River Metamorphics, Mareeba Granite, Atherton Basalt and unconsolidated alluvial sediments. Significant tectonic movement has lead to folding, heaving and faulting in the Barron River Metamorphics. The Mareeba Granites, which have intruded the metamorphics, are strongly foliated, crushed and granulated, with jointing providing some control on drainage system development (Muller, 1975). Both metamorphics and granite form basement rocks beneath the Mulgrave River floodplain. The uplifting and foliated nature of the geology has resulted in a relatively steep sided valley in the north with a broad ridge structure northeast of Gordonvale. The southern section of the Mulgrave River valley comprises a narrow, steep sided valley to the coastal area to join the Russell River valley.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 48 Public Environment Report Table 12: Stratigraphic Units (after Muller 1975)

BOUNDARY AGE UNIT LITHOLOGY REMARKS RELATIONSHIPS

Quaternary Alluvium (Qa) Gravel, sand, silt, clay Overlies basalt, granite, Origin – fluvial, colluvial and metamorphics and lacustrine; maximum thickness is possibly Tertiary 50m alluvium Alluvium (Qs) Quartz sand, fine to Shore line and beach deposits coarse

Alluvium (Qm) Organic silt and clay Associated with mangrove swamps

Pliocene to Atherton Basalt Interbedded Olivine basalt, Unconformably overlies Variable thickness, weathers Holocene (Cza) tuff and cinder deposits Mareeba Granite and easily Barron River Metamorphics

Tertiary Alluvium (Ta) Gravel, sand, silt, clay, Overlain by Atherton Fluvial and lacustrine origin, peat and inferior coal Basalt variable thickness

Carboniferous Mareeba Granite Granite, granodiorite Intrudes Barron River May be deeply weathered to Permian (Pgm) Metamorphics and overlain unconformably by Atherton Basalt

Middle Barron River Slate, thin bedded Intruded by Mareeba Usually weathered to considerable Palaeozoic Metamorphics siltstone, massive Granite and overlain by depth (Pzb) quartzite, greywacke; Atherton Basalt minor green schist

Note: Barron River Metamorphic later also known as Hodgkinson Metamorphics

42/15610/99537 Mulgrave River Aquifer Feasibility Study 49 Public Environment Report Figure 9: Geological Units in the Study Area

Figure 9: Geological Units in the study area

42/15610/99537 Mulgrave River Aquifer Feasibility Study 50 Public Environment Report The nature of the coarse, rounded basal Tertiary sediments encountered in drilling investigations suggests that the Mulgrave River may have once flowed north to Trinity Inlet. It has been suggested that the river was deflected southerly by stream capture by a southward flowing stream (Muller, 1975). It was also suggested that the river was diverted southwards by formation of the Mulgrave Fan and subsequent lowering of sea levels (Willmott and Stephenson, 1989). The Quaternary units are colluvial and the fan deposits are marginal to the valley and alluvial units within the valley. The characteristics of these units reflect their metamorphic or granitic source rocks. In most areas the Quaternary sediments are 30 m to 60 m thick, with a maximum thickness of 100 m (DNR, 1998a). There is significant lateral variability in sediment thickness and character, particularly in the marginal fan deposits (DNR, 1998a). Grainsize analysis undertaken in the 1973 investigation indicated sand and gravel units contained greater than 8% clay, silt and fine sand (Muller, 1975). Deposition of the fan deposits occurred in the Pleistocene where streams exited the ranges, with coarse material derived from the granites accumulating near the ranges and fining across the Mulgrave River valley. A later period of lower sea levels resulted in erosion of the fans leaving high level terraces. With a return to higher sea levels sediments were deposited within the eroded stream channels only (Willmott and Stephenson, 1989). Later work identified two distinct fan surfaces: a series of fans between 5 m and 10 m above the present floodplain, which have been extensively dissected and in places removed; and the lower level modern alluvial plains and floodplains that grade to sea level (Nott et. al., 2001). The Mulgrave River fan is the largest in the region and its distal portions extend over 10 km from the floodplain margin. The fan is 12 m to 15 m above the bed of the Mulgrave River and 6 m to 8 m above the surrounding floodplain (Nott et. al., 2001). At the fan margins, sands are at best medium grained and weathering ranges from bleached white and red/orange mottled clay and fine-grained sand to less weathered orange to red sand and clay.

4.7 Hydrogeology Table 13 summarises the major hydrogeological units in the Mulgrave River area. The technical Hydrology Report is provided in Appendix E.

Table 13: Major Hydrogeological Units

Groundwater Unit Aquifer Type Aquifer conditions Resource Potential

Quaternary Alluvium Sediment High Unconfined to confined

Atherton Basalt Fractured rock Low Confined

Tertiary Alluvium Sediment Moderate (uncertain) Confined

Basement (metamorphics Fractured rock Low Confined and granite)

4.7.1 Bedrock Aquifers The Barron River Metamorphics and Mareeba Granite form fractured rock aquifers on the margins of the Mulgrave River valley. Groundwater flow is dominated by topography, with recharge from rainfall

42/15610/99537 Mulgrave River Aquifer Feasibility Study 51 Public Environment Report infiltration and groundwater flow to streams and the alluvial aquifers beneath the floodplain. Yields are generally less than 2 L/s (DNR, 1998a).

4.7.2 Basalt Aquifer Although the basalt is often recorded as being fractured in drilling logs, it forms a poor aquifer of low yield (DNR, 1998a). Recharge occurs where the unit outcrops at Green Hill and via inflow from the overlying alluvium where the top of basalt has not been significantly weathered. As there are no observation bores in the basalt it is assumed that groundwater flow reflects that of the overlying Quaternary alluvium, with flow northerly from a groundwater divide coinciding with the surface water divide northeast of Gordonvale.

4.7.3 Tertiary Alluvial Aquifers There is currently no detailed information on the aquifer characteristics of basal sands within the valley. These basal sands are overlain by basalt for considerable areas and it is most likely that the tertiary aquiver is semi-confined to confined. It is assumed that the coarse nature of sediments would result in a relatively high hydraulic conductivity. Standing water levels are recorded as being between 1.5 and 15 m below the surface. As there are no observation bores in this tertiary alluvial aquifer it is assumed that groundwater flow reflects that of the overlying basalt and Quaternary alluvium, with flow northerly from the groundwater divide northeast of Gordonvale. Observation bores were drilled to investigate these aquifers as part of the Mulgrave Aquifer Feasibility Study (CRC, 2007); however both bores were abandoned due to the thickness of the overlying basalt. Where bores have been established in the tertiary alluvium (all north of the Mulgrave River) they have been located in areas of sparse basalt intrusion. Records of groundwater pump rates range from 0.65 to 3.9 L/s, with one bore (109611) recording 20 L/s. Groundwater salinity in two bores is 90 and 120 ppm. The distribution of Tertiary sediments is not well defined through current data and the groundwater resource potential is uncertain. The tertiary alluvial aquifers have not been examined in depth as a potential groundwater supply owing to the very high probability that the quality and quantity of water available are not viable as a developable resource. The hydrogeology technical report is included as Appendix E.

4.7.4 Quaternary Alluvial Aquifers The principal aquifers are formed by the Quaternary alluvial sediments between 15 and 45 m depth, with the major aquifers between 25 and 35 m depth (DNR, 1998a). They are believed to comprise fan deposits along the valley margins and floodplain deposits within the valley (DNR, 1998a). They are composed of poorly graded, moderately sorted sands and gravels with minor clayey zones and clay lenses. Individual aquifers are laterally variable. Silty and sandy clays may overlie the aquifers, providing semi-confining conditions to the underlying aquifers. A bore in the south was recorded as flowing at 0.5 L/s after construction. Yields up to 31 L/s have been reported for a bore northeast of Gordonvale (Muller, 1975). The quaternary alluvial aquifers are the principle resource under investigation. Details of the hydrological investigation are included in the technical report as Appendix E.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 52 Public Environment Report 4.8 Groundwater Assessment of the DERM bore monitoring data indicates that there is a rapid response in all bores to rainfall periods, including bores located further away from streams. As the bores distant from the creeks have higher groundwater levels, recharge occurs through direct rainfall infiltration or rapid recharge and groundwater inflow from elevated areas on the floodplain margins where the colluvial sediments may be more permeable. The nature of the sandy sediments in streambeds in the upper reaches of the streams and where they cross the floodplain margins suggests infiltration from surface water would occur. Anecdotal evidence indicates that during some dry seasons there is no surface flow in Behana Creek, with the flow infiltrating the sandy stream bed. The assertion is not that the creek runs dry, but rather that the creek is comprised predominantly of a series of interconnected waterholes, with the subsurface connection. Where the alluvial aquifers are partially or fully confined by overlying silty and sandy clays, recharge is primarily expected to occur as lateral inflow from unconfined areas and from the marginal bedrock aquifers. Discharge from the alluvial aquifers occurs to streams as base flow, flow down-gradient to coastal areas at Trinity (to the north) and Mutchero (to the south) Inlets and to a lesser degree through existing groundwater extraction. Review of the historical bore monitoring indicates that groundwater levels show some early response to reduced rainfall between early 1980s and late 1980s but then stabilise despite an overall continuation in reduced rainfall to the early 1990s. There is a further reduction in groundwater levels into the dry period from 2001. Overall, groundwater levels show a subdued impact to rainfall trends. Groundwater levels appear to respond more to seasonal (and hence annual) rainfall than the long-term rainfall trend. This suggests that seasonal rainfall exceeds the recharge capacity of the aquifer, and after an initial saturation of the soil profile additional rainfall in any single rainfall event in excess of the saturated infiltration rate cannot be accepted and becomes runoff. Dry years, where rainfall is significantly below annual average, have a much greater impact on groundwater levels than wet years that exceed recharge capacity. Following a dry period, recovery in groundwater levels occurs quickly when seasonal rainfall returns to average or better conditions. Previous investigations suggest that recharge commences within hours of rainfall onset and may continue for a week after rainfall events (Leach and Rose, 1979). It also appears, from a comparison of bore hydrographs and rainfall records, that recharge capacity was met by a daily rainfall of 100 mm, with excess rainfall becoming runoff (Leach and Rose, 1979). Seasonal fluctuations of between 2.5 and 10 m have been recorded in observation bores. Rapid rise in groundwater levels correspond to the commencement of the wet season, and levels decline into the dry season. In general, bores with the highest fluctuation are located on the margins of the floodplain or on the groundwater divide, where groundwater levels fluctuate seasonally by 6 to 10 m. Bores on the floodplain closer to streams record the least seasonal fluctuation in levels, between 1 and 6 m. The seasonal low groundwater levels may be controlled by stream infiltration (DNR, 1998a), particularly where streams cross the valley margins.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 53 Public Environment Report 4.9 Social Environment

4.9.1 Population Centres The Mulgrave River catchment is under the jurisdiction of the Cairns Regional Council Local Government Area (LGA). The Population Housing Fact Sheet of the Department of Infrastructure and Planning (August 2009) indicates the resident population of Cairns to be 147 538 with a projected population in 2021 of 195 540. The majority of the population is situated within Cairns City and towns such as Gordonvale. Pressures on infrastructure, economy and environment increase proportionately with population growth. Demands will increase for energy, water supplies, telecommunications and transport corridors. These factors inevitably lead to an increase in pest animal and plant species, agricultural diseases and pollution to name a few. A further 8700 hectares of the wet tropics is likely to be cleared to make way for urban development in the next twenty years (McDonald, and Weston 2004). Goldsborough Valley acreage is an example of urban sprawl in the Mulgrave River catchment. Similarly, there is increasing urban pressures on good quality agricultural land in the Mulgrave River valley. The majority of this has occurred north of the Mulgrave River, however there is potential for urban areas around Aloomba, Fishery Falls and Deeral to expand further into agricultural land. Urban expansion within a groundwater declared area has potential issues in relation to management of the aquifer resource, particularly water quality. The pressures faced by Cairns Regional Council in providing services to a growing population are illustrated in Table 14.

Table 14 Population projections, medium growth – Population and Housing Fact Sheet – August 2009 – Department of Infrastructure and planning

Local 2001 2006 2011 2016 2021 Annual Government average Area Growth Rate 2001-2021

Cairns 128 095 147 538 168 297 182 684 195 540 2.1%

4.9.2 Landuse and Tenure The Mulgrave River catchment has a variety of landuses and land tenure. Natural areas in the catchment are generally in elevated areas within sclerophyll or rainforest habitats or riparian areas and consist of rivers and creeks, wetlands and mangrove swamps (Connell Wagner, 1992). Urban areas are generally confined to the valley where land has been intensively farmed and townships are located around primary infrastructure such as the Gordonvale (Mulgrave) Mill. Gordonvale is the largest town in the catchment and is located on the Mulgrave River, with small townships of Aloomba, Fishery Falls and Deeral on the southern side of the river. The last three townships are entirely within the Mulgrave River aquifer investigation area. Agriculture is historically the most significant human landuse in the region and contributes to the employment and general economy of the region. Sugar cane production remains the major industry in the study area, with the sugar-processing mill at Gordonvale processing cane from farms both internal

42/15610/99537 Mulgrave River Aquifer Feasibility Study 54 Public Environment Report and external to the study area. Due to high rainfall and alluvial soils, the area remains highly productive compared to many other growing regions. Many service industries are dependent on the sugar industry for its existence. Tropical tree crops, bananas some vegetables and fodder are grown in the study area (Growcom stats 2004), although these industries are more prevalent in the Cassowary Coast Regional Council and on the Atherton Tablelands. Limited dairy, beef cattle and pig properties are also located in the area. Residential properties are continually expanding around Gordonvale and land previously used for growing cane is now being developed for estates. Originally, Gordonvale was developed around the Mulgrave Mill, which had a seasonal population boost once cane-crushing season began. In the current climate, the shift towards tourism continues to increase. Sugar cane and tree crop industries have suffered several blows due to shifts in market values, fuel costs and natural disasters making them an extremely variable job market. Many new residents looking for ‘the country life’ migrate to Cairns and other busy beachside townships for work in tourism and other industries. For example, over the ten-year period from 1991-2001 there was a 12.1% reduction in the area harvested for sugar, due primarily to loss of agricultural land to urban development (Cogle et al. 2004). In the long term, urban development will increase pressure on the river system particularly through water supply needs, land clearing, pollution (particularly sewerage) issues and fauna displacement (NRA, 2004, Cogle et al. 2004). Sand and gravel is extracted from the Mulgrave River for use in concrete and other industrial purposes. Historically, sand has been illegally extracted, however in the 1980’s it was placed under strict licensing agreements with the relevant authorities. The last available statistics indicate that in 1990, 79 570 m³ were extracted from Mulgrave River (Connell Wagner, 1992) in one year. Currently (with the exclusion of local government issued permits), there is one licence issued for the Mulgrave River flood plain, which allows for a maximum of 51 000 m³ of material to be extracted per year (Hales et al. 2004). Conservation is a large proportion of the land use in the Mulgrave River catchment. Connell Wagner (1992) identified that approximately 60% of the Russell-Mulgrave River catchment is designated for conservation purposes. Of this, it should be noted that the Mulgrave River Aquifer Area has less than 2% designated for conservation purposes, with this area being entirely within the southern reaches of the Mulgrave River and including Mutchero Inlet. The Mulgrave River catchment is popular with tourists and recreationists due to its diverse range of natural assets. There are National Parks, the World Heritage Listed Wet Tropics and the Great Barrier Reef Marine Park which provide a plethora of outdoor activities such as hiking, swimming, canoeing, bird watching, and there are ample spots outside of these protected areas for fishing and boating in the river and adjoining creeks and estuaries (Australian Atlas Website). Connell Wagner (1992) identified a wide range of commercial tours and clubs that utilise the resources, from scouting and horse riding to guided safari’s and wilderness tours. The study also identified that the major recreational benefits of the region to locals were not only the primary use of the natural attributes but also it’s contribution to the regions economic base and job provision. This has been further emphasised by Bentrupperbaumer and Reser (2003), who surveyed local residents and visitors on the perceived value of two world heritage areas in their region. The majority of respondents felt the world heritage areas benefited their lifestyles and increased the overall economy of the region. The area of the proposed infrastructure for the Mulgrave River aquifer proposal will incorporate varying landuse types and tenure. The current landuse and tenure for Stage 1 is summarised below.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 55 Public Environment Report Table 15: Tenure/Landuse in Proposed Infrastructure Areas

Infrastructure Segments Current land Use Proposed Land Use Tenure

Borefield Road reserve Bore Installations Local Government Controlled Dedicated Road.

Borefield delivery pipeline from Road reserve Construction of Local Government Controlled Dedicated borefield to Bruce Highway pipelines on road Road. reserve

Borefield delivery pipeline from Cane rail tramway Construction of Freehold, owned by Mulgrave Mill. borefield to Bruce Highway pipelines to pass beneath tram lines.

Bore water delivery pipeline to Road reserve and rail Construction of State Government Controlled Dedicated cross Bruce Highway and corridor pipelines beneath road and rail way reserves. railway. road and rail corridor.

Pipeline from Bruce Highway Road reserve Construction of Local Government Controlled Dedicated to Water Treatment Plant pipelines on road Road. reserve

Water Treatment Plant Cleared for Construction of water Freehold Agriculture treatment plant

4.9.3 Recreation Values The Mulgrave River and Mutchero Inlet are high profile key recreational fishing areas in North Queensland, with ready access, and a high diversity of species contributing to the popularity of the river and inlet. Commercial fishing is no longer undertaken in the Mutchero Inlet (with the WTQWHA), however the inlet is recognised as a critical nursery area for many species of commercial significance (e.g. prawns, crabs, barramundi), which are taken commercially outside the immediate area. The majority of the recreational fishing is undertaken in the tidal reaches, with target species typically including barramundi, grunter, bream and mangrove jack. Occasional pelagic species, such as trevally, are taken in the estuary, and king salmon are important on a seasonal migratory basis. Mud crabs are also taken throughout the tidal sections of the river. The major fish species are primarily estuarine species, none of them being entirely freshwater dependent excepting for portions of the life cycles of some species such as barramundi, and the majority of the species migrate freely between the lower and middle reaches of the Mulgrave River, with occasional incursions further upstream.

4.9.4 Visual Amenity The study area is within a highly agricultural landscape, and in itself does not contain any unique, rare or superlative natural phenomena, formation or features of exceptional natural beauty. However, the study area is bounded on either side by the WTQWHA, and the lower reaches of the Mulgrave River (in the WHA) represent an outstanding example of estuarine natural beauty. The only visible expression of the borefield will be the pump housing for the bores connecting the electrical connections to the pump (which will be installed inside the bore). The connecting pipework in the borefield will be primarily buried, except where there will be access to valve chambers, and inspection points along the lines. These are planned to be within the road reserves of the study area, and are not regarded as intrusive within the rural sugar cane landscape.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 56 Public Environment Report 5. Description of the Environment – Ecological

5.1 Information Sources Extensive reviews of available published and unpublished literature of the following species was undertaken, data obtained from the Queensland Herbarium database (HERBRECS), the Environmental Protection Agency (now DERM) Wildlife Online and the Queensland Museum databases. These databases are updated regularly and are the authoritative records of occurrence of fauna and flora in Queensland. The database information was supplemented with information supplied by the Wet Tropics Management Authority, DERM and anecdotal information from landholders in the study area. Based on a review of the existing data and research information, field surveys were undertaken to ascertain the habitat integrity of the listed species, their likely occurrence, and to assess likely impacts of abstraction from the Mulgrave River aquifer on these species. Surveys were undertaken both during the dry season (October 2006) and wet season (February 2007) to take into account seasonality of some of the species, non resident fauna species migratory through the area, or flowering phenology for identification purposes of some plant species. The results of the surveys are presented in the following sections. The associated discussions include World Heritage and National Heritage values of the WTQWHA (note that the World Heritage and the National Heritage values are the same but are only referred to as the World Heritage values in this report).

5.2 Species of National Environmental Significance Specific matters of NES identified by the Commonwealth in the PER guidelines include:

 Southern cassowary (Casuarius casuarius johnsonii);

 Torrent frog (Litoria nannotis) and Common Mistfrog (Litoria rheocola);

 Red goshawk (Erythrotriorchis radiatus) and the Australian Painted Snipe (Rostratula australis) (also listed migratory);

 Flora species, Dendrobium orchid (Dendrobium mirbelianum), Dendrobium nindii (an orchid), Eleocharis retroflexa (a sedge), water tassel-fern (Huperzia phlegmarioides); and

 Other listed migratory bird species that could occur in the project area that may be impacted by the proposal. In addition to the specific species, a number of other EPBC Act Listed species were also identified; these are listed in Table 16 and included in the summaries following the table.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 57 Public Environment Report Table 16: Species of NES Identified as Occurring within the study area

Common Name Species EPBC Act Qld NCA7 Status Notes Status

Antplant Myrmecodia beccarii Vulnerable Vulnerable Identified in field surveys

Spectacled flying-fox Pteropus conspicillatus Vulnerable Not listed Identified in field surveys

White-bellied sea- Haliaeetus leucogaster Listed Not listed Identified in field surveys eagle Migratory

Estuarine crocodile Crocodylus porosus Listed Vulnerable Identified in field surveys Migratory

5.2.1 Southern Cassowary The southern cassowary (Casuarius casuarius johnsonii) is currently recognised as a north-east Queensland endemic subspecies of a ratite species which occurs as the nominate subspecies of Casuarius casuarius. As a member of the primitive ratite group, the bird has Gondwanic origins and affiliations and represents an example of one of the values for which much of its habitat within the Wet Tropics achieved World Heritage status in 1988 (Werren 1993). Current populations are estimated at approximately 1,500 individuals in the Wet Tropics, although this may be an optimistic estimation with other estimations as low as 1,000 from various research sources. Three distinct cassowary populations are known; two on Cape York Peninsula and one within the Wet Tropics Biogeographic Region. The Cape York Peninsula range of the species stretches over 350 km along the eastern part of the Cape between the Stewart River (Silver Plains) in the south and the Jardine River in the north. Particular focus for management of the species occurs from the Paluma Range north of Townsville to the Big Tablelands near Cooktown, a distance of over 400 km. In 1993 the Russell-Mulgrave catchment was considered to have moderate populations of cassowaries (Werren 1993), however continued clearing of habitat and draining of wetlands in the lower reaches of the Mulgrave River Study Area (notably east of the Mulgrave River near Mutchero Inlet) since 1993 has resulted in the loss of the major cassowary habitat remaining in the lower Mulgrave River valley.

Survey Results Surveys between October 2006 and March 2007 were undertaken for evidence of cassowaries (scats and actual sightings) in the forested sections of the southern part of the study area, remnant forest continuous with the WTQWHA, and within the largest area of vegetated riparian habitat along Behana Creek. No evidence of cassowaries was noted, and anecdotal information from adjacent landholders indicated that none had been sighted in the general study area since approximately 1995. Significant clearing in the past of the coastal plains and foothills between the Russell and Mulgrave Rivers has resulted in the elimination of the majority of habitat for the species. Much of the Mulgrave River catchment coastal plain has been substantially modified and cleared for agriculture and residential development. Cane farming has significantly impacted the species in the area of the Mulgrave River, with little or no habitat left on freehold land in the area adjacent to the proposed bore field/supply infrastructure area.

7 Queensland Nature Conservation Act 1994 and associated Nature Conservation (Wildlife) Regulation 2006

42/15610/99537 Mulgrave River Aquifer Feasibility Study 58 Public Environment Report At the local level of relevance to the Mulgrave River Aquifer Project, no cassowaries have been identified during flora and fauna investigations of this study. Adjacent to the Mulgrave River Aquifer Area, cassowary habitat is protected within the Wet Tropics of Queensland World Heritage Area.

5.2.2 Red Goshawk (Erythrorichis radiatus) The red goshawk is a large raptor with a total body length of 45-58 cm and a wingspan of 110-135 cm. For a nest, it builds a large platform of dead sticks lined with twigs and green leaves. The nest is located in an exposed fork in the top of a living tree between 10 and 20 m above the ground. The same nest sites are used each year, and hence are relatively easy to identify when observed. The species breeds from April to November in the northern part of its range and may start breeding from August to November in the east. Females lay one or two eggs that hatch in 39-42 days, usually a few days apart. The red goshawk has an enormous home range covering between 50 and 220 square kilometres. It prefers a mix of vegetation types with its habitat including tall open forest, woodland, lightly treed savannah and the edge of rainforest. The Red Goshawk nests in tall trees (>20 m) within 1 km of a watercourse or wetland (Debus and Czechura, 1988; Aumann and Baker-Gabb, 1991). It occurs over eastern Queensland and across northern Australia. Much of the red goshawk's habitat has been cleared for urban development, agriculture and forestry. This has also reduced the availability of large nesting trees and prey. Heavy grazing and frequent burning may also contribute to a reduction in available prey. These are characteristics of the landscape of the Mulgrave River aquifer region, where agriculture and residential land has contributed to major loss of habitat for this species. There are now fewer than 1,000 adult goshawks left, with only an estimated 30-35 pairs in the Wet Tropics. All of these are associated with sclerophyll/rainforest boundaries primarily in the western part of the WTQWHA.

Survey Results No verified records exist for the Red Goshawk within the study area. There is no suitable habitat identified as suitable for red goshawks within the study area and the species was not observed during surveys. All large raptor nests examined were of other species.

5.2.3 Australian Painted Snipe (Rostratula australis) The Australian painted snipe is a poorly known wader inhabiting inland wetlands. The species derives from, and is presently also known as, Rostratula benghalensis australis = Rostratula australis.

The Australian painted snipe is usually found in shallow inland wetlands, either freshwater or brackish, that are either permanently or temporarily filled. It seems likely that the total population of mature individuals of Australian painted snipe is most likely greater than 1,000 mature individuals (DEWHA 2007c). The population size is not known, but Watkins (1993) estimated the population to be 1,500, while Garnett and Crowley (2000) estimated the population at 5,000 breeding birds. There is no other quantitative data available.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 59 Public Environment Report The trends in the available data and evidence are consistent and considered to be sufficient enough to indicate that the Australian painted snipe has declined substantially in numbers, with possible declines of up to 90% (DEWHA 2007c). The decline has been prolonged, is widespread and has occurred over various wet and dry cycles. The closest known primary habitat area occurs in the Fitzroy River Basin (approximately 1000 km south); however there are occasional reports of sightings in sub-coastal north Queensland, particularly around population centers where there are many shallow wetlands. The lack of shallow freshwater or brackish wetlands within the study area would suggest that available suitable habitat for this species is extremely restricted and it is unlikely, from a habitat utilisation perspective, that this species would be present in the study area. The likely causes of the decline of the Australian painted snipe are habitat modification and loss. The species has probably suffered considerably from wetland drainage and the diversion of water from rivers, which means that shallow wetlands, its key habitat, never form. There are no freshwater wetlands within the area of the proposed action.

Survey Results This species has not been recorded within the study area and was not identified during the field surveys. Preferable habitat for the species is not present, and it is extremely unlikely that the species would utilise any part of the study area.

5.2.4 Waterfall Frog (Litoria nannotis) A moderately large, robust species, with males 31.6 – 52.1 mm and females 48.2 – 59 mm in length. The species is restricted to rocky stream habitats in rainforest or wet sclerophyll forest where there is fast flowing water, waterfalls and cascades (DEWHA 2007b). Unlike most stream-breeding frog species that live in the adjacent forest and use the stream habitat for breeding, both male and female Waterfall Frogs use the stream as primary habitat throughout the year (DEWHA 2007b). Tadpoles of the Waterfall Frog are predominantly found in fast flowing sections of streams, in riffles or torrents, adhering to rocks. L. nannotis was not considered to be at risk as recently as 1990 (McDonald 1992, McDonald et al. 1991). Since 1990 population declines have been noted at upland sites throughout the Wet Tropics biogeographical region. The entire known distribution of this species is protected within the Wet Tropics of Queensland World Heritage Area, with 42.4% of known collection sites located within national parks, 53.1% within forestry reserves, 1.5% in other reserves and 3% on private lands (Northern Queensland Threatened Frogs Recovery Team 2001).

Survey Results The species was observed during surveys by GHD in the upper reaches of Behana Creek within the Wooroonooran National Park (outside the study area, but on a tributary of the Mulgrave River). It was not observed in the study area and is extremely unlikely to occur in the slow moving and sluggish sections of Behana Creek and the Mulgrave River in the study area).

5.2.5 Common Mistfrog (Litoria rheocola) A moderate size frog, with males 27 - 36.4 mm and females 31.7 - 41.2 mm in length. This species appears to be confined to rainforest areas of the Atherton Tableland and surrounding areas in north-

42/15610/99537 Mulgrave River Aquifer Feasibility Study 60 Public Environment Report eastern Queensland rainforest and wet sclerophyll forest between altitudes 0 and 1180 metres. It is found among rocks and logs in and beside swift mountain streams and waterfalls into which it jumps when disturbed (Connolly, Doak, and Pearson, 2006). L. rheocola is one of seven species of frogs occurring in the upland rainforest streams of north-eastern Queensland which have undergone rapid and substantial population declines in the last decade (Ingram and McDonald 1993, Richards et al. 1993, Trennery et al. 1994).

Survey Results There are no records of L. rheocola as occurring within the study area, and the species was not identified during surveys. The range of surface water features in the Mulgrave River Aquifer Study Area are not generally regarded as potential habitat for this species which is primarily restricted to fast flowing streams. The entire distribution of this species is protected within the Wet Tropics of Queensland World Heritage Area, with 32.6% of known collection sites located within national parks, 49.4% within forestry reserves, 5.6% in other reserves and 12.4% on private lands (Northern Queensland Threatened Frogs Recovery Team 2001).

5.2.6 Mangrove Orchid (Dendrobium mirbelianum) Mangrove orchid is widely recorded in the area from Northern Australia to Papua New Guinea as a medium to gigantic sized, low growing epiphyte in coastal lowland forests and swamps, or lithophyte on exposed rock outcrops in savannah regions. In north Queensland records are from tidally influenced vegetation complexes, primarily mangroves. The orchid is distinctive, with basally swollen, cane-like and leafy above carrying many, oval to ovate, thick, leathery, dark green with purple stripes leaves. Flowers are on a terminal or axillary, 20 to 45 cm long, horizontal to gracefully arching, several to many [10 to 30] flowered inflorescence with waxy, glossy, heavy textured flowers arising on old or leafed mature canes. Flowers occur throughout the year, often more than once. Owing to its desirability, the plant has been heavily harvested from the wild and is now extremely difficult to locate in easily accessible areas.

Survey Results The species has potential habitat within the intertidal mangrove swamp areas of the lower study area about Mutchero Inlet. These areas were surveyed by boat and where possible (and safe owing to crocodile presence) transects were undertaken in potential habitat areas. No examples were noted. There are no records from the Queensland Herbarium or the DERM Wildlife Online databases of any known records of this species.

5.2.7 Blue Orchid (Dendrobium nindii) The blue orchid is a distinctive epiphytic orchid forming tall, slender clumps with leathery dark green leaves to 15 cm long, and long stems bearing sprays of 10-20 flowers. The species is known to occur north of the Johnstone River area, favouring lowland coastal swamps and occasionally lowland gorges and occurs as far north as Papua New Guinea. It is a highly desirable plant for cultivation, and wild populations have been systematically harvested into near extinction. Additionally, many of the coastal lowland swamps have been drained and cleared for agriculture (including nearly all swamps in the Mulgrave River Study Area), and as a result habitat opportunities are extremely limited.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 61 Public Environment Report Survey Results Typical coastal habitats (predominantly mangrove dominated areas) were examined in the lower reaches of the Mulgrave River but the species was not identified in any of the sites examined. There are no records from the Queensland Herbarium or the DERM Wildlife Online databases of any known records of this species in the study area. The species was not observed in the study area, though areas of likely habitat are present in the lower reaches of the Mulgrave River about Mutchero Inlet.

5.2.8 Eleocharis retroflexa Eleocharis retroflexa is a semi-submerged member of the Cyperaceae family (sedges). It is a small sedge with 4-angled to 0.2 mm stems to 10 cm tall and grows in shallow water on the margins of seasonal swamps on lateritic substrates typical of the lower reaches of the adjacent Russell/Mulgrave River systems. Drainage of the lower areas of the Mulgrave River of much of the freshwater swamps of the study area had drastically reduced available habitat for this species.

Survey Results Groundwater dependent freshwater sedge swamps are now absent in the Mulgrave River Aquifer Area, and field surveys did not identify any suitable habitat nor identify any individuals of this species. There are no records from the Queensland Herbarium or by the DERM Wildlife Online databases of any known records of this species. Suitable habitat is known to occur in the adjacent Russell River catchment.

5.2.9 Layered Tassel Fern (Huperzia phlegmarioides) This species of tassel-fern is epiphytic and is a desirable horticultural species listed as Vulnerable under the Nature Conservation Act 1992, and Vulnerable nationally (Environment Protection and Biodiversity Conservation Act 1999) owing to a combination of harvesting in the wild and habitat clearing. The species is primarily associated with coastal lowland rainforests, and has a range extending from the wet tropics to Cape York Peninsula. Clearing of the majority of the lowland coastal rainforests in the Mulgrave River area has severely reduced available habitat opportunities and the species was not observed in the study area during field surveys.

Survey Results This species was extensively searched for in riparian rainforest communities, particularly the WTQWHA section adjacent the Mulgrave River in the middle/lower reaches of the study area. The species is not known to occur in the study area, with no formal records from the Queensland Herbarium or the DERM Wildlife Online database. The species was not observed in the survey areas during field investigations, and given the highly disturbed and fragmented nature of much of the riparian coastal lowland area is unlikely to be present.

5.2.10 Ant Plant (Myrmecodia beccarii) This epiphytic species was identified during the field surveys in 2007. The species is generally associated with the intertidal area of the lower Mulgrave River, particularly in mangrove forests on the edge of the landward side.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 62 Public Environment Report The species was not common, with only three individuals observed. All the observations were on the extreme southern boundary of the study area, and were in areas not predicted to be impacted by any abstraction from the Mulgrave River aquifer. The host species habitat is generally confined to coastal conditions and is not dependant on groundwater.

Myrmecodia beccarii (ant plant), one of three individuals observed in melalecua forest at the southern extremity of the study area.

5.2.11 Spectacled Flying fox (Pteropus conspicillatus) The spectacled flying fox has declined rapidly in population numbers in the last two decades as a result of habitat clearing and loss of foraging areas, and has been identified as ‘vulnerable’ by the Commonwealth under the provisions of the EPBC Act. Flying foxes are a common sight in the region, but large flocks are now a rarity.

Survey Results Flying foxes were observed on a number of occasions as individuals or in small family groups within the aquifer study area, but only one camp (of several hundred bats) was located in the lower Mulgrave River on the edge of Mutchero Inlet in a mixed mangrove/paperbark community. It is likely that the riparian vegetation along the Mulgrave River provides important foraging for this species, which specialises in rainforest (and orchard) fruits, and in blossoms particularly of paperbark (Melaleuca) species. However, owing to the limited extent of remnant riparian vegetation only very small populations of flying foxes could be expected to be supported by the riparian vegetation alone and it is more likely that the extensive rainforest of the WTQWHA adjacent the study area provide the critical resources necessary for this species.

5.2.12 White-breasted Sea-eagle (Haliaeetus leucogaster) This eagle is the second largest eagle in Australia (after the wedge-tailed eagle) and is an extremely distinctive large bird. This species nests in tall emergent trees near water. As its name suggests, this species primarily frequents areas on the coast - although it has been recorded in western Queensland.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 63 Public Environment Report The eagle will prey on virtually any animal, but the diet particularly includes fish (which it actively takes from the water), mammals, waterfowl and it will eat carrion such as dugong carcasses or trawler bycatch washed up on beaches.

Survey Results This bird was identified roosting on trees and in flight over in the lower Mulgrave River, near the Deeral Landing. It is a nomadic species and is listed as Migratory under the provisions of the EPBC Act, although it tends to be more nomadic within a large home range than truly migratory. Many tall emergent trees near water are present and it is highly probable that this species could have a nest somewhere in the study area, although no nest was observed during field investigations.

5.2.13 Estuarine Crocodile (Crocodylus porosus), The estuarine (or salt-water) crocodile is ubiquitous in coastal rivers and streams in northern Australia, and its presence should be anticipated in any such water in the tropics. Crocodiles will feed on almost any prey, and the abundance of fish (and feral pigs in the lower Mulgrave) ensures that a ready resource is always available.

Survey Results During field surveys three C.porosus (two in excess of three metres long) were observed in the Mulgrave River, and given the territoriality of the species it is highly probable each animal had a home range that was roughly centred on its location. The largest animal was identified in the lower Mulgrave River (Mutchero Inlet) in an area of mixed wetland/rainforest mosaic, and these vegetation complexes are often the preferred areas for female crocodiles to build nests for egg incubation away from the main river channel. Opportunities for nesting are extremely limited outside the Mutchero Inlet area as the vegetation outside the immediate tidal estuary area has primarily been cleared, and where present is mostly complex rainforest unsuitable for nesting.

Estuarine crocodile on banks of Mulgrave River near Aloomba

42/15610/99537 Mulgrave River Aquifer Feasibility Study 64 Public Environment Report 5.3 Queensland Species of Conservation Significance In addition to the species identified by the Commonwealth in the PER guidelines, field surveys identified a number of other listed protected species during the course of the field work. These include plants listed under the EPBC Act and the Queensland Nature Conservation Act 1992.

Four other plant species of conservation significance were confirmed as occurring within the aquifer study area as a result of the field investigations, these included:

 Myrmecodia beccarii (ant plant); listed as Vulnerable under the EPBC Act and Vulnerable under the Queensland Nature Conservation Act 1992;

 Torrenticola queenslandica (no common name), listed as Vulnerable under the Queensland Nature Conservation Act 1992;

 Pseuduvaria mulgraveana, listed as Rare under the Queensland Nature Conservation Act 1992; and

 Polyalthia patinata (syn. Polyalthia sp Wyvuri B.P.Hyland RFK2632) listed as Rare under the Queensland Nature Conservation Act 1992.

5.3.1 Myrmecodia beccarii Previously described in Section 5.2.10.

5.3.2 Torrenticola queenslandica This species is a submerged macrophyte growing as a lithophyte on granite boulders in fast flowing reaches of rainforest streams commonly encountered in the Wet Tropics. This species was identified beneath the Bruce Highway crossing of Figtree Creek (refer Figure 10) growing as a colony on granite substrate. This was on the very edge of the study area (approximately 20 m AHD). There were additional sightings of this species in other streams, but all of these were westwards of the study area at higher altitudes within the WTQWHA.

Torrenticola queenslandica growing on granite substrates in Figtree Creek underneath the Bruce Highway bridge over the creek.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 65 Public Environment Report 5.3.3 Pseuduvaria mulgraveana var mulgraveana Pseuduvaria mulgraveana var. mulgraveana is a small tree/shrub, and three individuals were identified in riparian rainforest in the middle to lower reaches of the Mulgrave River. The species is commonly found in mesophyll and complex mesophyll rainforest in the area south of Cairns, and its presence in complex mesophyll vine forest in the study area is not unexpected. The species tolerates a range of soil and drainage conditions, but is more common on the well drained lower ridges and footslopes of the adjacent foothills than in coastal, less well drained soils. It is not a species directly reliant on groundwater resources, but in the location that it was identified in the surrounding community was considered to be seasonally groundwater dependent.

Pseuduvaria mulgraveana var mulgraveana in complex mesophyll vine forest on alluvium in the mid/lower reaches of the Mulgrave River

5.3.4 Polyalthia patinata This is a small to medium tree (to 20 m) and is a relatively common occurrence in rainforest in coastal areas between Cairns and Innisfail. In the study area one tree and one sapling (same locality) were identified in rainforest on the banks of the Mulgrave River near the southern end of the study area (towards Mutchero Inlet). The species was observed in a community dominated by feather palms (Archontonphoenix alexandrae) which are considered to be very vulnerable to changes in groundwater status. Locations for all the survey results are provided in Figure 10. Further details in relation to the areas that were and were not subject to the field surveys are provided in the Flora and Fauna Report (Appendix F).

42/15610/99537 Mulgrave River Aquifer Feasibility Study 66 Public Environment Report Figure 10: Regional Ecosystem Conservation Status and Protected Species Observations

42/15610/99537 Mulgrave River Aquifer Feasibility Study 67 Public Environment Report 5.4 Pest Species The two primary invasive species of concern are the introduced fish Tilapia mariae (mangrove cichlid or tilapia), and the widespread tree Annona glabra (pond apple). Both species are abundant and locally dominant in the Mulgrave River aquifer study area and are also present in Behana Creek. The Mulgrave River is a major research study area by government agencies in terms of examining the impacts of both of these species. There is interest in the potential change of river base flows as a result of abstraction on the abundance and distribution of these species. Two serious riparian weed grass species Hymenachne amplexicaulis and Urochloa mutica (para grass) also occur in the Mulgrave River aquifer study area.

5.4.1 Tilapia mariae Tilapia can mature from 9-18 cm in smaller sizes but can measure up to 40 cm in total length. Adults have a strongly compressed and oval-shaped body, with large eyes, rounded snout and small mouth with thickened lips, compared to that of the juveniles. Both sexes are similar in size and appearance with dark olive green to light yellow green with 8-9 dark bars (less evident in adults and 2-6 large dark spots along middle of side between the bars (JCU, 2006)). It is mainly planktivorous (feeding on unicell algae), but is an opportunistic feeder on filamentous and blue green algae, detritus, leafy aquatic plants, invertebrates and fish eggs (JCU, 2006).

Tilapia mariae

Tilapia inhabits still or flowing water in rocky or mud-bottom areas, in both non-tidal and estuarine reaches. It was introduced to Australia for aquarium trade and is now present in three catchments in northern Queensland: the Barron River, the Mulgrave-Russell system and the North and South Johnstone Rivers system (JCU, 2006). Tilapia are distributed in the Mulgrave River from the tidal areas in the Deeral township locality to areas upstream of the river outside of the aquifer area (to at least Peets Bridge). It occurs in Behana Creek, but does not prefer faster flowing or saline habitats. It is known to breed in all cane drains, minor waterways, as well as Behana Creek downstream of the Bruce Highway and the Mulgrave River itself. Unlike many native freshwater fishes, tipalia are able to retreat downstream into highly saline waters during drought and move back upstream when conditions improve. This ability gives them the advantage to live in a more conducive habitat than the native fish species.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 68 Public Environment Report Tilapia invasion to local river systems has dominated many aquatic habitats due to its highly efficient reproductive strategy, simple food requirements and its ability to live in a variety of conditions. In addition, its aggressiveness helps effectively in competing for habitat and food (DPI&F, 2009).

5.4.2 Annona glabra Annona glabra, pond apple, is a widespread small tree originally introduced as rootstock for the commercial custard apple in 1912. It is a semi-deciduous tree that grows to 3-6 m in height and can reach up to 15 m. The tree is now a widespread pest of artificial drains, riverbanks, and most brackish and tidally influenced swamps in north Queensland. It covers around 2000 ha of the wet tropics between Cardwell and Cooktown. The pond apple seeds and fruits are easily dispersed by water and animals, which contributes to its wide distribution. This tree requires moist soil with regular inundations of fresh to brackish water (DPI&F, 2007). Pond apple is a major environmental weed of the Wet Tropics bioregion of Far North Queensland and a Weed of National Significance (WONS). It has an alarming ability to invade relatively undisturbed areas. It is also a pioneering tree and will opportunistically invade areas after disturbance such as cyclones and floods. Disturbed, flood-prone ecosystems are most at risk from pond apple invasion, particularly mangroves, melaleuca woodlands, riparian areas, drainage lines, coastal dunes and islands (DPI&F, 2007).

Field Surveys Pond apple was widespread and evident in most reaches of the Mulgrave River and Behana Creek. The densest areas of infestation were observed in the lower reaches of the Mulgrave River, where mature pond apple was observed overtopping the canopy of many rainforest trees in these areas with estimated heights exceeding 20 m. These areas were generally in the intertidal areas of the Mulgrave River and subject to a daily tidal variation in river height. Generally isolated individuals and small groves were identified along the entire length of the Mulgrave River and lower Behana Creek. The species was less common in the mid – reaches of Behana Creek, and was not observed in the reaches of Behana Creek above the Bruce Highway.

5.4.3 Hymenachne (Hymenachne amplexicaulis) This weed is a perennial, robust grass to 2.5 m tall and can grow above or below water, with its roots in the ground. Introduced as a ponded pasture species, hymenachne occurs in all seasonally flooded tropical wetlands, which makes the Mulgrave River valley a conducive habitat. Its ability to reproduce both from seed and broken stem fragments makes this species amenable to rapid distribution by both animals (particularly water birds) and flooding events. Being an aggressive species, hymenanchne can outcompete many native species, and in areas of dense infestations precludes seedling establishment and creates conditions favourable to the entrapment of sediment, enabling further recruitment of the species.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 69 Public Environment Report Field Surveys Hymenachne does not tolerate brackish water and does not thrive in well shaded areas. The greatest density of hymenachne was observed in cane drains, minor tributaries and along open banks of the Mulgrave River and Behana Creek where riparian cover was minimal, in the mid to upper reaches of both systems.

5.4.4 Para grass (Urochloa mutica) Para grass (Urochloa mutica) is a perennial grass and ubiquitous to North Queensland tropical streams. It grows up to 1 m in height with hollow and robust stems and generally dominates the shallow water and banks of any area of disturbed riparian habitat along the freshwater margins of all streams in the Wet Tropics. Similar to hymenachne, the species was introduced as a ponded pasture fodder species, and since has become well established in north Queensland wetlands and waterways. This plant can be a very aggressive invader, particularly in low-lying ungrazed areas and in sugar cane crops. It is often found in wet situations, especially drains, but will also grow in deep soils in non-swampy areas. The ability to thrive in wet areas highlights its potential as a threat to natural wetland ecosystems.

Field Surveys Para grass cannot establish in deep (below .5 to 1m) water, and cannot tolerate saline conditions or areas of deep shade. Consequently, the species is not established in densely vegetated rainforest clad riparian areas, but rapidly colonises sand and gravel bars, disturbed banks and areas of poor riparian cover. This grass was observed to dominate most open riparian areas along both the Mulgrave River and Behana Creek, sometimes in association with hymenachne, which is able to establish in deeper water.

5.5 Vegetation Communities The Mulgrave River Aquifer Area is generally demarcated by the extent of alluvium deposition in the river valley, approximating the 20 m topographic contour line. Within this boundary the Mulgrave River valley has been extensively cleared, with less than 10% of the original vegetation remaining. This remnant vegetation consists primarily as a discontinuous band of riparian vegetation on the Mulgrave River and tributaries. The largest tract of continuous vegetation in the study area is in the southern section, and consists primarily of extensive mangrove and mixed intertidal swamp areas at the limit of the aquifers. Regional ecosystems are the basis upon which the Vegetation Management Act 1999 (VMA) is based. Across Queensland the Environmental Protection Agency (now DERM) has mapped and classified vegetation based on parent geology and substrate, landform and floristic composition. These mapped units are referred to as ‘regional ecosystems’ and are conferred a conservation status under the VMA based on the threat level to the regional ecosystem across the state and on the remaining proportion of the regional ecosystem by comparisons with pre-clearing (e.g.: comparison between before European settlement and current extent of clearing of that regional ecosystem). Over 90% of the study area has been cleared of vegetation, which in pre-European times was primarily a mosaic dominated by various rainforest regional ecosystems. Across the state, the particular types of rainforest that dominated the Mulgrave River valley have been cleared to less than 25% of its original extent, and consequently the majority of the vegetation in the Mulgrave River aquifer study area has

42/15610/99537 Mulgrave River Aquifer Feasibility Study 70 Public Environment Report been classified as endangered’ under the VMA (refer Table 17). Thirteen regional ecosystems occur within the aquifer study area. Of these, five are classified under the VMA as endangered, two are classified as ‘of concern’, and the remaining six are classified as ‘not of concern’. The most extensive of the remnant vegetation in the aquifer area of influence is endangered complex/mixed mesophyll vine forest types, typified by species which have a seasonal groundwater dependency. The remnant regional ecosystems represented in the study area can be broadly broken down into groundwater dependent ecosystems (riparian vegetation, swamp/swales and other such communities) and non-groundwater dependent ecosystems (generally vegetation above the 20 m contour interval), and including some Eucalypt and Bloodwood dominated communities. The groundwater dependent ecosystems can be further subdivided into two types: an obligate riparian ecosystem reliant on a combination of groundwater/surface interactions, and the other an entirely groundwater dependent system. The first is the representative riparian vegetation of the Mulgrave River and tributaries, consisting of a mosaic of vegetation (mostly rainforest) communities with distinctive species assemblages. The second are obligate groundwater ecosystems (palm/tea tree swamps) to be found in the vegetation communities of the lower Mulgrave River, adjacent to Mutchero inlet, and extending a short way up the Mulgrave River into the aquifer study area. The non-swamp vegetation communities are primarily seasonally dependent on the aquifer. That is, it is groundwater dependent during the dry season and maintained by surface water infiltration during the rest of the year. These seasonally dependent groundwater ecosystems are represented along most of the length of the Mulgrave River by varied mosaics of riparian rainforest dominated regional ecosystems. A summary of the regional ecosystems and their groundwater dependency is shown in Table 17.

Table 17: Summary of Regional Ecosystems and Groundwater Dependencies

Regional Ecosystem Conservation Notes Groundwater Dependency Status under the Qld Vegetation Management Act

Mangrove forests on coastal lowland Not of Concern Extensive areas occur to the Not connected to the saline alluvial soils (RE 7.1.1) north of Gordonvale and aquifer. Not dependent on surrounding Mutchero Inlet. groundwater interactions.

Alexandra palm (Archontophoenix Endangered Occurs primarily at southern Groundwater dependent alexandrae) swamp vine forest on end of aquifer at the vegetation. Two variations very wet poorly drained fertile landward interface of present of this type, with lowlands (RE 7.3.3). (See note at end intertidal and terrestrial varying degrees of of section). ecosystems. dependency. Groundwater to these communities supplied by primarily surface runoff from the Malbon Thomson Ranges, and not from aquifer.

Swamp paperbark (Melaleuca Of Concern Small areas occur around Groundwater dependent quinquenervia) open forest on very Mutchero Inlet. ecosystem. Once wet and wet poorly drained lowlands widespread in lower (RE 7.3.5) Mulgrave River, now reduced to small remnants.

Paperbark (Melaleuca leucadendra ± Endangered Occurs primarily at southern Seasonally groundwater M. quinquenervia ± M. dealbata) open end of aquifer, although a dependent. Reliant on forest, ± an under storey of vine forest small area occurs along a surface flows during wet species, on very wet poorly drained stream feeding into Trinity season, but groundwater lowlands (RE 7.3.6). Inlet. dependent during dry.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 71 Public Environment Report Regional Ecosystem Conservation Notes Groundwater Dependency Status under the Qld Vegetation Management Act

Coastal floodplain forest red Endangered Occurs primarily at southern Groundwater dependent gum/melaleuca (Eucalyptus end of aquifer study area. ecosystem, but outside the tereticornis/Melaleuca spp.) open Occurs entirely within the sphere of influence of the forest complex on moist to very wet World Heritage Area. Mulgrave River aquifer. poorly drained lowlands (RE 7.3.7).

Complex mesophyll vine forest on Endangered Mapped with other Seasonally groundwater very wet well drained fertile lowland communities along the dependent. During dry alluvial soils (RE 7.3.10) middle reaches of the seasons and low flow events Mulgrave River and tributary maintained by aquifer streams. connection to riparian areas.

Forest red gum (Eucalyptus Endangered Occurs in Mulgrave Valley Seasonally groundwater tereticornis) woodland, or popular gum upstream of the Bruce dependent during prolonged (E. platyphylla) and Clarkson's Highway Bridge. Also dry season events. bloodwood (Corymbia clarksoniana) mapped in small areas woodland on very wet to wet, well around Trinity Inlet. drained lowland alluvial soils (RE 7.3.12).

Complex mesophyll vine forest on Not of Concern Occurs primarily on foothills Not a groundwater very wet, well drained lowland and surrounding aquifer area. dependent ecosystem, but foothill piedmont fans (RE 7.3.17) has many species shared with riparian complex rainforest.

Pink bloodwood (Corymbia Not of Concern Occurs primarily on foothills Not a groundwater intermedia) woodland on moist to dry surrounding aquifer area. dependent ecosystem, no metamorphic foothills and uplands connection to the aquifer. (RE 7.11.19)

Mesophyll riparian vine forest on moist Of Concern Riparian community occurs in Seasonally groundwater well drained lowland alluvial levees small patches along the dependent. During dry (RE 7.3.22) Mulgrave River lower Behana seasons and low flow events Creek and streams feeding maintained by aquifer into Trinity Inlet. connection to riparian areas.

Riparian herbfield/shrubland on river Endangered The community is mapped Seasonally groundwater and stream bed alluvia (RE 7.3.28) along the Mulgrave River as dependent. During wet far as the tidal limit. season is completely inundated, but during dry season reliant on aquifer connection.

Complex notophyll vine forest with Not of Concern Occurs on foothills and hills Not a groundwater kauri pine (Agathis robusta) with a southerly to easterly dependent ecosystem, no emergents on moist metamorphic aspect surrounding aquifer connection to aquifer. foothills and uplands (RE 7.11.7) area.

Red stringy bark (Eucalyptus pellita) Not of Concern Mapped on foothills and hills Not a groundwater woodland of the wet to moist surrounding aquifer area. dependent ecosystem in the metamorphic lowlands and foothills study area, no direct (RE 7.11.17) connection to the aquifer.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 72 Public Environment Report 5.6 Regional Ecosystem Types and Integrity The Mulgrave River Aquifer Area is dominated by rural landuses although there is an increasing expansion of residential development particularly in the upper Mulgrave River valley, and in the area about Gordonvale. Although the Mulgrave River catchment has had extensive development of agriculture, particularly sugar cane in the middle and lower reaches, the upper reaches are well protected by World Heritage listing. Within the immediate aquifer study area, less than 10% of the original vegetation of the Mulgrave River coastal valley remains, and faunal habitats have consequently been subjected to a variety of ongoing impacts. Habitats within the aquifer study area are represented by the following:

 Terrestrial habitats – naturally vegetated areas now comprising primarily discontinuous riparian vegetation along the Mulgrave River and associated tributaries;

 Intertidal and wetland habitats – areas of lower Mulgrave River influenced by tidal activity and comprising a mosaic of vegetation community types dominated by mangroves;

 Estuary (marine) habitats – the extreme lower end of the study area with permanent saline water present; and

 Freshwater habitats – instream habitats with little to no tidal impacts and dominated by freshwater flows. The river maintains natural instream connectivity by virtue of its perennial nature and replenishment via wet season flows. However, some instream habitat values have been lost due to reduced riparian vegetation and intensive land use such as grazing and cropping. The intensive landuse and reduced riparian vegetation have resulted in sedimentation and changes to the natural habitat (Rayment and Bohl, 2002). Despite the regular heavy rainfall experienced in the area, lower floodplain areas have been extensively drained and cleared. Where the area was once dominated by lowland rainforest and wetlands, there is little remnant habitat remaining. Each of the habitats represented has been affected by anthropogenic activity at differing levels, and subsequently the integrity of each of the above is consequentially variable. These habitat types also have differing attributes in relation to their vulnerability to impacts arising from abstraction from the Mulgrave River aquifer.

5.6.1 Groundwater Dependent Systems and Conservation Status Feather palm swamp wetlands are found in the lowland floodplain and estuarine complexes of river drainage systems. Refer to Figure 11. They occur in very wet lowland swamps, generally less than 15 m above sea level, on waterlogged alluvial soils where the watertable is always very high. The soils of these areas are derived from basaltic and granitic parent material, and are generally highly fertile when drained. The agricultural potential of these wetlands was recognised soon after European settlement and consequently they have largely been cleared. Those that remain today are generally on poorer soils. Feather palms get their common name from their pinnate (featherlike) leaves that reach up to two metres long. The palms grow to approximately 20 m tall and dominate the swamp wetland, with up to 150 000 stems per hectare in some sites. Seedling palms form up to 95% of the total number of palm stems.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 73 Public Environment Report Feather palm swamp wetlands formerly occurred on the coastal plain most frequently between Tully and Cairns. However, from an original extent of 4 648 ha, less than 1 821 ha of feather palm swamp wetlands remain in scattered remnants extending along the coastal strip from just north of the Daintree River in the north to just south of Ingham in the south (a range of only 225 km). Of this, the majority (1 013 ha) of feather palm swamp wetland remnants occur on national park tenure. A further 631 ha occur on freehold land — commonly on agricultural land as strips and patches along drainage lines. This community was previously a distinctive feature of the lower Mulgrave River Study Area and now only exists as endangered remnants in the southern and lower middle reaches of the Mulgrave River. Two types of feather palm swamp wetland occur in different positions along the Mulgrave River (Stanton and Stanton, 2004, Small 1999). One type, a “Barringtonia type”, occurs on low-lying aggrading sediments and has freshwater mangrove Barringtonia racemosa as a commonly occurring subcanopy species. This variation is present in the lower middle reaches of the Mulgrave River and is directly groundwater dependent on the aquifer/river connection. A second feather palm swamp wetland type occurs in topographical depressions in alluvial areas remote from active channels. These primarily occur in the lower reaches of the Mulgrave River near Mutchero Inlet and are more often on the landward side of the intertidal zone. Its presence in saline influenced areas is made possible by the surface water runoff from Malbon Thompson Range ameliorating the intertidal saline conditions. These remnants contain species that are shared with adjacent mesophyll vine forests and are more floristically complex than other feather palm community variations. In a 1998 study (CSIRO Hopkins and Graham), 191 species of plants were recorded in feather palm swamp wetlands. Of these, 60% were scattered emergent trees, some reaching 36 m in height, each species generally occurring only in small numbers, and often in only a few individual sites. Other plants included a variety of shrubs, vines, epiphytes and herbs. Most species in the palm swamp wetlands were found relatively widespread in other forest types beyond the feather palm swamp wetlands, and often reflected the species composition of neighbouring rainforest communities. Feather palms have very shallow root systems (less than 2 m) that are incapable of reaching any groundwater at depth. They are not considered to be groundwater dependent on the resources of the Mulgrave River aquifer in the landscape positions in which they occur. In the Mutchero Inlet area, at the junction of the Russell/Mulgrave Rivers, the juxtaposition of the communities to the Bellenden Ker Range (which receives in excess of 9 m of rainfall in a year) allows recharge of the communities by shallow subsurface flows from this range and enables these palm communities to survive in tidal conditions.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 74 Public Environment Report Figure 11: Vegetation Communities and Groundwater Dependencies

42/15610/99537 Mulgrave River Aquifer Feasibility Study 75 Public Environment Report 5.7 Aquatic Values

5.7.1 Fish Species Aquatic habitats consist of two key types, the daily tidal area of the Mulgrave River considered permanently estuarine (generally from the Deeral Landing to the mouth), and the middle to upper reaches of the Mulgrave and Behana Creek, generally with little to no tidal activity, dominated by freshwater flows and mostly a gently sloping river bed with steeply rising tributaries (Pusey et al. 1995). The demarcation between these two habitats is blurred by the tidal regime of the Mulgrave River, which extends along most of the middle reaches of the Mulgrave River to a point approximately east of Aloomba. Consequently, there is a rather eclectic assemblage of aquatic species ranging from entirely estuarine obligate, to entirely freshwater obligate, with a wide range of species able to tolerate either fresh or saline water conditions for varying lengths of time. Some species, such as barramundi, are dependent during its life cycles on both fresh and saline conditions. Consequently, it is not unexpected that the Mulgrave River and Behana Creek has one of the highest diversities of fish species in the region with over 70 species recorded, four of which are endemic and three introduced (Pusey et al. 1995, Rayner 2007) with forty-six freshwater fish species reported from Behana Creek alone. The studies of the Mulgrave River catchment have variously reported:

 Thirty-six species from the range of habitats within the Mulgrave River (Pusey et al. 1995);

 Ninety-four species in the Russel and Mulgrave Rivers from the estuary to the upper catchment though a large proportion of these (56) were estuarine species from Mutchero Inlet (Russell et al. (2004);

 Thirty species from four streams in the Russel/Mulgrave catchments (Pusey et al. 2007); and

 Thirty-six species in the lowland main channel sites of the Mulgrave River Rayner (2007). The species captured in these studies and those reported in Pusey et al. (2004), along with their distribution and habitat requirements, are presented in Table 18. Only species that have been reported as occurring in the Mulgrave River are included in Table 18, with those reported in Russell et al. (2004) that were mostly estuarine species in Table 19. The fish present in the Mulgrave River are typical of the rivers and streams of the Wet Tropics region where rainbowfish, blue-eyes, glassfish, catfish and grunters are the most common families and gobys and gudgeons the most speciose families (Kroon and Johnson 2006, Pusey et al. 2007). The most abundant species in the Mulgrave River include empire gudgeon (Hypseleotris compressa), eastern rainbowfish (Melanotaenia splendida), Cairns rainbowfish (Cairnsichthys rhombosomoides), eel-tailed catfish (Tandanus tandanus), Pacific blue-eye (Pseudomugil signifier), Mulgrave River goby (Glossobius sp. 4), long-finned eel (Anguilla reinhardtii) and fly-specked hardyhead (Craterocephalus stercusmuscarum) (Pusey et al. 1995, Pusey et al. 2007).

Within the Mulgrave River catchment habitat structure and diversity, stream width and substrate, extent of riparian cover, and catchment position and area all influence fish assemblage structure (Pusey et al. 1995, Pusey et al. 2007). Generally diversity decreases upstream with the decreasing stream size, catchment area and diversity of habitats. The small tributaries and streams usually with higher gradient, faster flows and coarser substrate have mostly small species such as rainbowfish (e.g. Cairns rainbowfish), some gobies (e.g. Mulgrave River goby) and gudgeons (e.g. purple-spotted gudgeon).

42/15610/99537 Mulgrave River Aquifer Feasibility Study 76 Public Environment Report While the larger downstream river has more diverse habitats and an increasingly complex community structure that include those fish with an estuarine phase and the larger carnivorous species such as catfish, jungle perch and barramundi (Pusey et al. 1995, Russell et al. 2004, Pusey et al. 2007). It has been suggested that the predictable and constant flow regimes of the Mulgrave River may have allowed the development of restricted habitat preferences by some of the fish species and this may account for the high diversity of fish within this system. This high diversity of freshwater fishes and low number of introduced species suggest that the Mulgrave River retains high ecological value, is considered ‘healthy’ and is one of the Wet Tropics most important catchments with respect to maintaining fish assemblages (NQ Joint Board 1998, Pusey et al. 2007). For many of the fish in the Mulgrave River, the reproductive biology is not fully understood; for some it is entirely unknown and for others the spawning behaviour is known but not its timing. The reproductive modes include those that are entirely freshwater and those that migrate to spawn, either into estuarine/marine waters or upstream into freshwater. Nearly all the Mulgrave River fish whose timing of spawning is known have been reported as spawning during the summer months, that is, in the wet season. There are a few species, for example the Roman nose goby, that spawn over a longer period including both the wet and dry season, spawn opportunistically at any time of the year (blue-eyes), or have a peak spawning in winter-spring (though spawning fish are present from April-December (Cairns rainbowfish)(Table 18). Only three fish are thought to spawn during the dry season in the Mulgrave River, though this timing is only a suggestion based on very limited data. A cardinal fish (mouth almighty) is thought to spawn at this time so the young are large enough to feed on the increased numbers of small fishes present in the wet season, however this species has also been recorded as spawning in the wet season in the Northern Territory. The Mulgrave River goby’s and the scaleless goby’s reproductive biology knowledge is very limited and based on the collection of gravid females from August to November respectively, led to the suggestion that these species both spawn during the dry season (Pusey et al. 2004).

The majority of the fish in the Mulgrave River are reported to be tolerant of a fairly wide range of environmental conditions, variations in dissolved oxygen, temperature, pH, conductivity and turbidity. The environmental tolerances of most of the gobies and some gudgeons are less well known as the only information available is based on ambient conditions in the water at the time the species was collected and was generally found to be typical of rainforest streams and rivers of the region.

5.7.2 Endemic, Rare and Protected Fish There are a number of freshwater fish species in the Mulgrave River system that are endemic, rare, protected and/or have restricted distributions (Table 18):

 Endemic to Wet Tropics region - Cairns rainbowfish, Mulgrave River goby, scaleless goby and Tully grunter;

 Endemic to Australia - catfish (Hyrtl’rs tandan, Eel-tailed catfish), Pacific blue-eye, bullrout, Agassiz’s glassfish, Allen’s cling goby and purple-spotted gudgeon;

 Rare - Agassiz’s perchlet and purple-spotted gudgeon;

 Protected - belly pipefish and short-tailed river pipefish;

42/15610/99537 Mulgrave River Aquifer Feasibility Study 77 Public Environment Report  Restricted distribution - all the rainbowfish and blue-eyes, fly-specked hardyhead, sooty grunter, Roman nose goby, flag-tailed glassfish, sand bream and most of the gudgeons - greenback guavina, brown gudgeon, ebony gudgeon, snakehead gudgeon, Empire gudgeon and Aru gudgeon. The four species present in the Mulgrave River that are endemic to the Wet Tropics region are described in more detail below: Cairns rainbowfish (Cairnsichthys rhombosomoides), Mulgrave River goby (Glossobius sp. 4), scaleless goby (Schismatogobius sp.) and Tully grunter (Hephaestus tulliensis).

Cairns rainbowfish (Cairnsichthys rhombosomoides) is limited to the Wet Tropics region most likely between Trinity Inlet and Hull River near Mission Beach (Table 18). It is widespread and abundant in the Mulgrave/Russell and Johnstone Rivers and occurs in small adventitious lowland streams and small upland tributary streams below 100 m a.s.l with good riparian cover and mostly shallow (30-50 cm) areas of high water quality. It appears to tolerate a range in temperature (15-28qC), dissolved oxygen (5-10 mg/L), pH (5-8), conductivity (6-63 PS/cm) and turbidity (0.2-18 NTU). Spawning fish are present from April-December with peak spawning activity from August to October. Fecundity increases with body size, eggs are small and numerous and deposited in batches within root masses. Larvae are confined to areas of zero flow close to some form of cover and away from areas of bright sunlight. The diet of this species is not well documented but appears to be dominated by small terrestrial invertebrates (Pusey et al. 2004). This species is listed as Rare by the Action Plan for Australian Freshwater Fishes (Wagner and Jackson 1993) and Vulnerable by the Australian Society for Fish Biology ASFB (2003). The Mulgrave River goby (Glossobius sp 4) apparently has a very restricted distribution that is limited to discrete rivers and creeks in Far North Queensland (Table 18). It is widely distributed and moderately abundant in the Mulgrave River and is present in a range of habitats from the main river channel to small tributary streams. It is most abundant in medium-sized streams with moderate riparian cover and rapid, riffle and run habitats. It occurs in a wide range of water speeds and depths and is a benthic species most commonly found in coarse substrates. It has mostly been recorded in areas of high water quality with ranges in temperature typical of Wet Tropics rainforest streams (17-27qC), dissolved oxygen levels typical of riffle/rapid habitats (6-11 mg/L), pH near neutral (6-8), low conductivity (13-47PS/cm) and high water clarity (0.4-2 NTU) (though this may be a reflection of values at the time of sampling rather than tolerances). Very little is known about their reproductive biology, except that spawning probably occurs during the dry season at a time of low, relatively stable flows and that the life history is most likely entirely in freshwater. The diet in the dry season was observed to consist almost entirely of immature stages of aquatic insects in riffle habitats (Pusey et al. 2004). Its highly restricted distribution has led to conservation listing of this species. It is currently listed as Lower Risk-Near Threatened by the ASFB (2003) and Rare by the Action Plan for Australian Freshwater Fishes (Wagner and Jackson 1993). The scaleless goby (Schismatogobius sp.) is limited to the Wet Tropics region and has been recorded in drainages from the Endeavour to Liverpool (Table 18). It is not an abundant or frequently encountered species and has a highly restricted habitat preference, confined to about 3 m at the head of a riffle or rapid with swiftly flowing water within 50 km of the river mouth and <50 m a.s.l. It most commonly occurs in the transitional area between pools and rapids in shallow (30 cm) water and is a benthic species that is found in the interstices of rock and cobble substrate. Pusey et al. (2004) p466 states that “this is perhaps the most restricted habitat requirement at all scales in the hierarchical habitat array, of any of the species in the region studied by us”. The environmental tolerances are little known, though all occurrences of this fish have been in areas of extremely good water quality. Reproductive information is from two individuals and suggests that spawning occurs in the dry season with low and stable flows, and that each female spawns once only and maybe only with one male. The diet is most likely small insect

42/15610/99537 Mulgrave River Aquifer Feasibility Study 78 Public Environment Report larvae typical of fast flowing streams (Pusey et al. 2004). This species is listed as Non-Threatened by Wagner and Jackson (1993) and not listed by the ASFB. Pusey et al. (2004) suggests that the restricted distribution of this species, similar to the Cairns rainbowfish and Mulgrave River goby warrant reassessment of the conservation status of this species. The Tully grunter (Hephaestus tulliensis) is limited to the Wet Tropics region and has been reported between the Daintree River and the Herbert River (Table 18). It is abundant and widespread with juveniles frequently seen foraging in loose schools in open areas of stream-bed while adults are considered solitary. It occurs in a wide range of habitats from small headwater tributary streams to large lowland river areas, though is most common in fourth–order streams with intact riparian cover, 40 cm deep, moderately fast flowing water and diverse substrate. Its environmental tolerances appear to be fairly wide ranging, though Pusey et al. (2004) urges caution in interpreting the available information as it is based in ambient conditions over three years in streams it has been recorded from; temperature (18- 32qC), dissolved oxygen (5-9 mg/L); pH of 6-8; conductivity (8-68PS/cm) and turbidity of 0.3-30 NTU). Its reproductive biology is almost entirely unknown. Two individuals have been observed spawning in shallow still water near to a fast flowing rapid and there is anecdotal evidence that an upstream spawning migration may occur. The diet in the dry season was observed to be dominated by aquatic insects and aquatic plant material with ontogenetic variation in the diet, for example, larger fish consumed similar amounts of filamentous algae and macrophytes while small fish consumed only filamentous algae. This species has no conservation status listing; despite a restricted distribution it is locally abundant (Pusey et al. 2004).

Two other fish species are listed as rare by the Action Plan for Freshwater Fish (Wagner and Jackson 1993): the purple-spotted gudgeon (Mogdurna adspersa) and Agassiz’s perchlet (Amabssis agassizi); the former most likely based on substantial declines of their distribution and abundance in the southern portion of the Murray-Darling Basin and the latter on declines in populations of inland populations (Pusey et al. 2004).

There are four freshwater pipefish present in Australia, two of which have been recorded from the Mulgrave River; belly pipefish (Hippichthys heptagonus) (Jones et al. 2007) and short-tailed river pipefish (Microphis brachyurus brachyurus) (Rayner 2007). The belly pipefish occurs elsewhere in the world, in Australia its distribution is limited to the east coast of Australia from Cape York to northern New South Wales (Allen et al. 2002) and it may have restricted habitat requirements; limited to lower reaches of freshwater systems by the availability of the predominant prey, planktonic crustaceans (Table 18) (Jones et al. 2007). The short-tailed river pipefish occurs in Asia and Oceania but in Australia has a distribution restricted to Cape York (Allen et al. 2002) and more recently has been recorded from the Mulgrave River (Rayner 2007). It is present in freshwater streams, rivers and estuaries in relatively shallow (25-150 cm), still to slow-flowing water. Juveniles and subadults are usually found in estuaries while adults are found upstream in freshwater areas (Table 18) (Froese and Pauly 2009). All sygnathids (seahorse and pipefish) are protected in Australia with both of these species on the List of Marine Species of the EPBC Act.

5.7.3 Introduced Fish Species Of concern are three fish species, mangrove cichlid (tilapia), guppy (Poecilia reticulata) and platy (Xiphophorus maculatus); all of which have been identified in a Vertebrate Pest Risk Assessment

42/15610/99537 Mulgrave River Aquifer Feasibility Study 79 Public Environment Report developed by the Rainforest CRC (Harrison and Congdon 2001). Tilapia is considered a noxious pest species and discussed in detail above (Section 5.4). The guppy was introduced mainly for mosquito control and as an aquarium fish and has established wild populations in eastern and southern Australia. They can survive conditions that native fish cannot and have the potential to dominate waterways, fish communities and cause habitat disturbance. They are considered a potential pest; Table 18 describes their habitat requirements. The platy are an introduced popular aquarium fish that are established around Brisbane and the Wet Tropics region and, similarly to the guppy, are able to survive in habitats that native fish cannot (Table 18). This, in addition to their high productiveness allows them to dominate waterways particularly those that have become very degraded. They are considered a potential pest fish (DEEDI 2009). Both the guppy and the platy are listed as a non-indigenous fish under Schedule 6 of the Fisheries Regulations 1995 and may be retained in aquariums but cannot be released to the wild or used as bait with high penalties for illegal release (DEEDI 2009).

42/15610/99537 Mulgrave River Aquifer Feasibility Study 80 Public Environment Report Table 18: Freshwater Fish Species in the Mulgrave River

Family Name Species Name Distribution Habitat Comments Common name Common name

Sygnathidae Hippichthys Africa, Asia and Oceania. In Distribution may be limited to lower reaches of freshwater EPBC Act List of Marine heptagonus Australia on the east coast from systems by availability of predominant prey, planktonic Species Pipefish Cape York to the Clarence River crustaceans (Jones et al. 2007). Belly pipefish (NSW) (Allen et al. 2002, Froese and Pauly 2009).

Microphis brachyurus Asia, Africa, Western Atlantic Relatively shallow slow-flowing water; freshwater streams, EPBC Act List of Marine brachyurus and Oceania. In Australia in the rivers and estuaries. Juveniles and subadults are usually Species eastern drainages of Cape York found in estuaries while adults are found upstream in Short-tailed river Peninsula (Allen et al. 2002, freshwater areas. Feeds on worms, crustaceans and pipefish Froese and Pauly 2009). zooplankton (Froese and Pauly 2009). Recorded in the Mulgrave River by Rayner (2007).

Megalopidae Megalops East Africa to Tahiti. In Australia Most abundant in marine and estuarine waters, but juveniles cyprinoides * coastal seas of tropical northern and small adult frequent freshwater reaches of rivers in Tarpons Australia (Allen et al. 2002). clear or turbid waters. They are tolerant of a wide range in Tarpon pH (Allen et al. 2002). Spawning occurs in the estuarine or near shore marine waters most likely in the wet season (Pusey et al. 2004).

Anguillidae Anguilla obscura South-western Pacific and Freshwater streams, lakes and swamps, prefers coastal common in coastal drainages lagoons and lower reaches of rivers. Diet is mainly Freshwater eels Pacific short- finned from Cape York to Mackay (Allen crustaceans, fish and molluscs. Adults migrate to marine eel et al. 2002). waters to spawn over a long period with the peak in summer and autumn, juveniles return to freshwater. Sub-adults mostly in estuarine or fresh waters. (Allen et al. 2002, Pusey et al. 2004).

Anguilla reinhardtii Commonly occurs in New Preferred habitat is rivers, also in coastal lagoons, streams, Caledonia, New Guinea and lakes, swamps and farm dams. Diet includes crustaceans, Long-finned eel eastern Australian coastal molluscs, aquatic and terrestrial insects and fish. Adults drainage areas from Cape York migrate to the Coral Sea to spawn in deep water over a long to northern Tasmania (Allen et period with the peak in summer and autumn, juveniles move al. 2002). into fresh water (Froese and Pauly, 2009, Allen et al. 2002).

42/15610/99537 Mulgrave River Aquifer Feasibility Study 81 Public Environment Report Family Name Species Name Distribution Habitat Comments Common name Common name

Clupeidae Nematolosa erebi Widespread and common Variety of habitats, commonly in shallows of still or slow- throughout northern and south flowing rivers and streams, often in turbid waters. Wide Herrings Bony bream eastern Australia (Allen et al. tolerance of temperature and pH, susceptible to oxygen 2002). depletion. (Allen et al. 2002). Flexible life history with spawning in northern Australia all year peaking in the wet season (Pusey et al. 2004).

Herklotsichthys cf Restricted to the Southwest Schooling species found in coastal marine and estuarine castelnaui** Pacific and eastern Australia waters and also in freshwater (Froese and Pauly 2009). from Queensland to New South Herring Wales (Froese and Pauly 2009)

Plotosidae Neosilurus ater Southern New Guinea and Prefers bottom of fast flowing sections of streams and rivers relatively common in disjunct though also occurs in still or slow flowing water of pools and Catfishes Narrow-fronted range across northern Australia channels. Tolerant of wide range of environmental catfish from Western Australia to conditions. Reproductive mode is entirely freshwater, breed Queensland (Allen et al. 2002). during wet season (Pusey et al. 2007).

Neosilurus hyrtlii Endemic to Australia, common Diverse habitats from still or flowing waters in streams, Endemic to Australia and widespread across tropical rivers, lakes and stagnant pools. Forms shoals and diet Hyrtl’s tandan northern Australia and central includes insects, crustaceans and molluscs (Froese and Australia (Allen et al. 2002). Pauly 2009). Tolerant of wide range of environmental conditions. Reproductive mode is likely entirely freshwater, spawn during wet season (Pusey et al. 2004).

Porochilus rendahli Widely but patchily distributed Clear or turbid water in bottoms of lowland lagoons, flowing across northern Australia from creeks and backwaters close to aquatic vegetation. Rendahls’ catfish Kimberley area to northeastern Sometimes forms large shoals. Botttom feeder of aquatic Queensland (Allen et al. 2002, insects, small crustaceans, molluscs and detritus. Tolerant Pusey et al. 2004). of wide range of environmental conditions. Adults migrate into flooded lowland lagoons to breed in early wet season; all animals including juveniles migrate back upstream into freshwater in dry season (Allen et al. 2002, Pusey et al. 2004).

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Tandanus tandanus Endemic in Australia, widely Inhabits bottom waters of slow moving streams, lakes and Endemic to Australia distributed throughout eastern ponds with fringing vegetation, prefers lakes more than Eel-tailed catfish coastal Australia and the Murray- flowing water. Mostly solitary but juveniles form loose Darling River system (Allen et al. aggregations. Diet includes insect larvae, crustaceans, 2002). molluscs, and small fishes. A hardy species that breeds in freshwater during spring and mid-summer (Allen et al. 2002, Pusey et al. 2004).

Hemiramphidae Arrahamphus Indo-West Pacific, in Australia Shallow coastal marine waters and estuaries into lower sclerolepis* from central West Australia north freshwater reaches of rivers and streams. Commonly forms Garfishes to Queensland and New South large grazing shoals. May move into estuaries to breed Snub-nosed garfish Wales (Allen et al. 2002). during the wet season (Allen et al. 2002, Pusey et al. 2004).

Atherinidae Craterocephalus Southern New Guinea and Primarily found in fresh water streams and rivers, lakes, Restricted distribution to stercusmuscarum relatively common in northern ponds and reservoirs. Tolerant of wide range of New Guinea and Hardyheads and eastern Australia (Allen et environmental conditions. Shoal forming and seasonally Australia Fly-specked al. 2002, Froese and Pauly abundant at some locations, breeds from October to hardyhead 2009). February and capable of multiple spawnings. Reproductive mode entirely freshwater (Allen et al. 2002). Pusey et al. 2007).

Melanotaeniidae Cairnsichthys Endemic to Wet tropics region Small streams with good riparian, varying substrates and Endemic to Wet Tropics rhombosomoides with a restricted distribution. It flow rates. Tolerant of wide range of environmental Listed as Rare by Action Rainbowfishes has been recorded from conditions. Reproductive mode entirely freshwater with Cairns rainbowfish Russell/Mulgrave drainage, peak spawning in spring (August to October) (Pusey et al. Plan for Australian Freshwater Fishes Johnstone River, Liverpool and 2004, Pusey et al. 2007). Maria drainage and North Hull River. Likely to occur in streams of Trinity Inlet (Pusey et al. 2004).

Melanotaenia Isolated populations in Clear waters of small creeks and Pandanus swamps with Isolated populations in maccullochi southwestern Papua New plenty of shelter (aquatic plants, log debris). Information on northern Australia Guinea and northern Australia. environmental tolerance lacking. Reproductive mode McCulloch’s Recorded in the Mulgrave River entirely freshwater, spawning most likely in the wet season rainbowfish Drainage Basin, specifically from (Pusey et al. 2004, Pusey et al. 2007). Behana Creek (Pusey et al. 2004).

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Melanotaenia Papua New Guinea and Highly variable; rivers, streams, swamps, marshy lagoons Restricted distribution to splendida Northern Australia where it is and lakes, often forming large schools at the surface and New Guinea and usually abundant where it occurs around sunlit edges of lakes and swamps. Most abundant Australia Eastern rainbowfish (Allen et al. 2002). in areas of minimal water flow but also occurs below rapids (Allen et al. 2002). Tolerant of wide range of environmental conditions. Reproductive mode entirely freshwater, peak spawning in wet season (Pusey et al. 2004, Pusey et al. 2007).

Pseudomugullidae Pseudomugil signifer Endemic to East Australian coast Highly variable ranging from marine to freshwater with Endemic to Australia from Cooktown to southern New coastal habitat usually mangrove areas or offshore islands. Blue-eyes Pacific blue-eye South Wales, common and Common in clear forest streams. Wide tolerance range of widely distributed (Allen et al. temperature and pH. Reproductive mode entirely 2002). freshwater and opportunistic- at any time of the year (Allen et al. 2002, Pusey et al. 2007).

Pseudomugil New Guinea and in fragmented Variety of habitats; small creeks in open country, swamps, Isolated populations in gertrudae and localised populations in marshes, rainforest streams. Aggregations are common in northern Australia northern Australia (Allen et al. areas of abundant vegetation and log debris. Tolerant of Spotted blue-eye 2002). acidic waters, intolerant of low dissolved oxygen and water temperatures. Reproductive mode entirely freshwater and opportunistic - at any time of the year (Allen et al. 2002, Pusey et al. 2004, Pusey et al. 2007).

Synbranchidae Ophisternon gutturale Widely distributed in fresh and Lower reaches of coastal streams in soft bottom sediments estuarine waters of subtropical of quiet well vegetated backwaters of estuaries and swamps Swamp eels Swamp eel and tropical Asia and and lower reaches of freshwater. Can survive short periods Australasia. (Pusey et al. 2004). out of water. Reproductive mode entirely freshwater (Allen et al. 2002, Pusey et al. 2007).

Scorpaenidae Notesthes robusta Widespread and fairly common Bottom dwelling in still or slow flowing freshwater streams Endemic to Australia in eastern Australian coastal over rock, mud or gravel usually within 50 km of the coast. Scorpionfishes Bullrout drainages from Daintree River to Commonly found near vegetation, woody debris in streams. southern New South Wales Tolerant of wide range of environmental conditions. In (Allen et al. 2002). periods of high rain may migrate downstream into estuarine waters, not clear if breeds in estuaries or freshwater (Allen et al. 2002, Pusey et al. 2004).

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Chandidae Ambassis agassizii Endemic to eastern Australia; Variety of freshwater habitats including still or flowing Endemic to eastern relatively widespread and lowland and upland rivers, creeks, reservoirs, ponds, Australia Perchlet Agassiz's glassfish common in coastal and inland drainage ditches and swamps. Diet mainly of aquatic drainages and also present on insects and microcrustaceans May be tolerant of wide range Listed as Rare by Action Fraser Island and North of environmental conditions. Reproductive mode entirely Plan for Australian Stradbroke Island. Was freshwater and breeding season from spring to autumn Freshwater Fishes previously widespread throught (Pusey et al. 2004). Murray Darling Basin but is now thought to be extinct in South Australia and Victoria (Pusey et al. 2004).

Ambassis agrammus Southern New Guinea and Rivers and creeks in rainforest, sometimes in stagnant pools Restricted distribution to locally abundant in Australian and margins of lakes and swamps. Can form large schools New Guinea and Sailfin glassfish disjunct populations from Gulf of among aquatic vegetation, breeds at start of wet season northern Australia Carpentaria, Cape York and feeds mainly on microcrustaceans. Adults migrate Peninsula and Wet Tropics downstream prior to spawning (Allen et al. 2002, Pusey et region (Pusey et al. 2004). al. 2004).

Ambassis miops Indo-west Pacific. In Australia Clear flowing creeks usually within 20 km of the coast. Restricted Australian locally common but very Probably tolerant of elevated turbidity and salinity, intolerant distribution Flag-tailed glassfish restricted distribution; eastern of low water temperatures. It possibly has a marine larval Cape York and Wet tropics phase (Allen et al. 2002, Pusey et al. 2004). region (Pusey et al. 2004).

Latidae Lates calcarifer East Africa, Asia and common Freshwater rivers and billabongs, common beneath and widespread in coastal undercut banks and submerged logs. Also occurs in Barramundi Barramundi drainages of northern Australia brackish estuaries and coastal bays in clear and turbid from Shark Bay to southern waters. Carnivorous diet of mostly fish and crustaceans. Queensland (Allen et al. 2002). Changes sex from male to female at around 80 cm (Allen et al. 2002).

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Terapontidae Hephaestus Southern New Guinea and Most common in upper reaches of large flowing streams Restricted distribution to fuliginosus northern Australia where it is over rocky or sandy bottoms with sparse aquatic vegetation. New Guinea and Grunters abundant throughout coastal Can tolerate acidic conditions. Reproductive mode is northern Australia Sooty grunter drainages of Northern Territory, entirely freshwater and in Wet Tropics spawning tends to Gulf of Carpentaria and precede wet season flooding (Allen et al. 2002, Pusey et al. northeast Queensland (Allen et 2004, Pusey et al. 2007). al. 2002).

Hephaestus tulliensis Endemic to Wet Tropics region Wide range of habitats from small headwater tributary Endemic to Wet Tropics with a restricted distribution streams to large lowland river areas, intact riparian cover, region. Tully grunter range from Daintree to Herbert moderately fast flowing water and diverse substrate. River (Pusey et al. 2004). Environmental tolerances appear to be fairly wide ranging. The requirement for fresh or estuarine waters for reproduction is unknown (Pusey et al. 2004).

Mesophrestes Widely distributed in Indo-Pacific Mostly a marine species, but juveniles enter brackish Restricted Australian argenteus** but in Australia present in only a estuaries and the lower freshwater reaches of rivers (Allen distribution few locations in far north et al. 2002). Sand bream Queensland (Allen et al. 2002).

Therapon jarbua** Widespread and common in Mostly a shallow coastal marine species though also Indo-west Pacific and northern commonly penetrates estuaries and lower freshwater Crescent perch tropical Australia (Allen et al. reaches of rivers. Spawning occurs at sea (Allen et al. 2002). 2002, Froese and Pauly 2009).

Kuhliidae Kuhlia rupestris Africa, Asia and Oceania, Fast flowing streams and rivers, mostly in rainforests and in patchily but locally common in rocky pools below waterfalls. Environmental tolerances Flagtails Jungle perch coastal areas of northeast appear to be fairly wide ranging. Reproductive modes are Australia from Cape York to poorly known, though it is thought that spawning occurs in Fraser Island (Allen et al. 2002). estuarine or near shore marine areas during the wet season (Allen et al. 2002, Pusey et al. 2004).

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Apogonidae Glossamia aprion Asia and Oceania, New Guinea Still or gently flowing water of rivers, streams, pools, lakes, and common and locally swamps and reservoirs often in the shallow margins of well Cardinalfishes Mouth almighty abundant in northern Australia vegetated water bodies. Male is a mouth brooder. Solitary (Allen et al. 2002, Froese and and carnivorous fish feeding on small fishes and Pauly 2009). crustaceans, aquatic and terrestrial insects. Tolerant of high temperatures and wide range in pH. Reproductive mode entirely freshwater with spawning suggested as occurring in the dry season in Wet Tropics region (Allen et al. 2002, Pusey et al. 2007, Froese and Pauly 2009).

Toxotidae Toxotes chatareus Asia, Oceania and common in Lower and middle reaches of coastal drainages, can northern Australia from Derby to penetrate hundreds of kilometres inland. Commonly occurs Archerfishes Seven spot central Queensland (Allen et al. in mangrove-lined estuaries, freshwater streams, lakes and archerfish 2002, Froese and Pauly 2009). billabongs around overhanging vegetation. Diet includes crustaceans, small fishes and vegetation. Breeds in both fresh and brackish water in the wet season (Allen et al. 2002, Froese and Pauly 2009).

Mugulidae Mugil cephalus* Worldwide distribution in tropical, Coastal waters, estuaries and fresh water. Young fish travel subtropical and temperate zones into coastal rivers and mature fish travel up the coast for Mullets Mullet (Pusey et al. 2004). annual spawning migration (Froese and Pauly 2009).

Gobiidae Awaous acritosus Southern New Guinea and Clear flowing lowland streams, mostly on gravel or sand Restricted distribution to relatively widespread and bottoms near aquatic vegetation. Tolerant of moderate New Guinea and Gobies Roman nose goby uncommon in coastal drainages range of water quality. Reproductive biology poorly known northern Australia of northeastern Queensland but thought adults live in freshwater and seasonally migrate between Cooktown and from August to December to the riffle closest to river mouth Townsville (Allen et al. 2002, (but still in freshwater) to spawn (Pusey et al. 2004). Pusey et al. 2004, Froese and Pauly 2009).

Glossogobius sp 1. Western Pacific and in Australia Clear flowing streams with rocky or gravel bottoms, mostly Restricted Australian locally common but restricted to close to the sea. Environmental tolerances unknown. No distribution Mountain goby Cape York and the Wet Tropics information on reproductive biology but a marine larval region (Pusey et al. 2004). phase may occur (Pusey et al. 2004).

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Glossobius sp 4 Endemic species with restricted Occurs in streams ranging from main channels to small Endemic to Wet Tropics distribution. Recorded from tributaries. Most abundant in shallow, rapid, riffle and run region Mulgrave river goby Mulgrave/Russel basin, Hills habitats. Recorded in high quality waters only. Creek and Falls Creek (eastern Reproductive mode is most likely entirely freshwater with Listed as Rare by Action side of Trinity Inlet) and several spawning possibly in the dry season (Pusey et al 2004, Plan for Australian creeks near Mossman (Kroon Kroon and Johnson 2006). Freshwater Fishes and Johnson 2006).

Mugilogobius Widely distributed throughout Restricted microhabitat to very small, low gradient streams notospilus Pacific, in Australia Far north with intact riparian cover close to the coast, maximum Queensland where it can be distance from river mouth recorded is 14 km. Environmental Pacific mangrove locally abundant (Pusey et al. tolerances unknown. Reproductive biology poorly known but goby 2004). likely that there is a planktonic marine interval (Pusey et al. 2004).

Redigobius Western Pacific, widely Wide range of habitats from brackish mangrove estuaries bikolanus* distributed and moderately and lower reaches of freshwater streams to upland streams, abundant in northern Australia most common in medium sized streams within 30 km of the Speckled goby from central Western Australia to sea. Environmental tolerances unknown. Reproductive Brisbane (Allen et al. 2002, biology is poorly known, may be entirely freshwater life Pusey et al. 2004). cycle, or there may be an estuarine or marine larval interval (Pusey et al. 2004).

Schismatogobius sp. Endemic to the Wet Tropics Occurs within 50 km of river mouth. Has only been found in Endemic to Wet Tropics Region. Recorded from riffle/run areas with swiftly flowing water, substrate rocks region. Scaleless goby Endeavour, Daintree, Mossman, and cobbles. Environmental tolerances poorly known. The Mulgrave, Russel, Johnstone requirement for fresh or estuarine waters for reproduction is and Liverpool drainages (Pusey unknown with spawning possibly in the dry season (Pusey et al. 2004). et al. 2004).

Stiphodon alleni Endemic to north Queensland, Inhabits clear, moderately fast-flowing water over substrates Endemic to north currently known only from strewn with cobbles or boulders. One of two recently Queensland Allen’s cling goby Harvey Creek near Deeral, discovered Australian cling-gobies (Allen et al. 2002, Froese Queensland (Allen et al. 2002). and Pauly 2009).

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Eleotridae Bunaka gyrinoides Indo-West Pacific with an Most commonly in rainforest streams on mud bottoms and Restricted Australian Australian distribution restricted undercut banks. Environmental tolerances unknown. distribution Gudgeons Greenback guavina to northeast coast drainages, Reproductive biology poorly known but likely that there is a most commonly but not marine larval phase (Allen et al. 2002, Pusey et al. 2004). abundantly within the Wet Tropics region (Pusey et al. 2004).

Eleotris fusca * Widely distributed in the Indo- Brackish estuaries and lower reaches of freshwater Restricted Australian West Pacific, in Australia streams, mostly on mud bottoms. Environmental tolerances distribution Brown gudgeon restricted to the east coast of unknown. Reproductive biology poorly known but it is northern Queensland (Pusey et possible they migrate to marine waters to spawn (Pusey et al. 2004). al. 2004).

Eleotris melanosoma Widely distributed in the Indo- Brackish estuaries and lower reaches of freshwater Restricted Australian * West Pacific, in Australia streams, mostly on mud bottoms. Environmental tolerances distribution restricted to the east coast of unknown. Reproductive biology poorly known but it is Ebony gudgeon northern Queensland (Pusey et possible they migrate to marine waters to spawn (Pusey et al. 2004). al. 2004).

Giurus margaritacea Widely distributed in the Indo- Variety of habitats including rivers, coastal streams, swamps Restricted Australian West Pacific, in Australia and floodplains. On mud bottoms, often amongst dense distribution Snakehead gudgeon restricted to the east coast of vegetation and undercut banks. Environmental tolerances northern Queensland (Pusey et unknown. Reproductive biology poorly known but it is al. 2004). possible they migrate to estuarine waters to spawn and there is a pelagic marine larval phase (Allen et al. 2002, Pusey et al. 2004).

Hypseleotris Papua New Guinea and in Most common in lower reaches of rivers, though also Restricted distribution to compressa Australia a common species in present upstream, in still or flowing water around aquatic New Guinea and coastal drainages from the plants and fallen branches. Can tolerate saline water and Australia Empire gudgeon Kimberley to southern New high temperatures and pH. Reproductive mode can be South Wales (Allen et al. 2002). entirely freshwater, juveniles and adults can occur in estuaries but unknown whether they spawn there. Breeding season from summer to autumn (Allen et al. 2002, Pusey et al. 2004).

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Mogurnda adspersa Endemic to Australia, Rivers, creeks and billabongs in slow-flowing or still waters, Endemic to Australia widespread and abundant in often among vegetation and over rocks. Diet includes Purple-spotted Listed as Rare by Action coastal drainages of eastern worms, insect larvae, crustaceans and mosquito fishes. gudgeon Australia, though there have Appears to be tolerant of wide range of environmental Plan for Australian Freshwater Fishes been large declines in the conditions Spawns during rainy season. Reproductive southern portion of the Murray mode entirely freshwater (Pusey et al. 2004, Pusey et al. Darling basin (Pusey et al. 2007). 2004).

Ophiocara Widely distributed in the Indo- Mainly in brackish estuaries, river mouths and freshwater porocephala West Pacific, in Australia from creeks at low elvations close to the sea. Juveniles are the northern and eastern coasts usually found in rocky creeks near the coast (Allen et al. Spangled gudgeon from west Kimberleys to 2002, Froese and Pauly 2009). southern Queensland (Allen et al. 2002).

Oxyeleotris aruensis Northern Queensland and Papua Creeks and rivers, usually over gravel or mud bottoms. Restricted distribution in New Guinea. Limited distribution Environmental tolerances unknown. Reproductive mode is Wet Tropics. Aru gudgeon in the Mulgrave, Russell and considered to be entirely freshwater (Allen et al. 2002, Tully Rivers (Pusey et al. 2004). Pusey et al. 2004).

Oxyeleotris lineolata Common and widespread in Rivers, creeks, billabongs, commonly in slow flowing or still tropical northern Australia from water among vegetation, undercut banks and log debris. Sleepy cod west Kimberley to southern Diet includes insects, crustaceans and fish. Environmental Queensland. Occurrence in tolerances appear to be fairly wide ranging. Spawns southern Papua New Guinea October to February. (Allen et al. 2002, Pusey et al. 2004). remains unconfirmed (Allen et al. 2002, Pusey et al. 2004).

Lutjanidae Lutjanus Indo-West Pacific. Widely Primarily a marine fish, adults are often found in groups argentimaculatus** distributed in tropical Australia around coral reefs, juveniles and young adults often occur Snappers from Kimberley, Western in mangrove estuaries and lower reaches of freshwater Mangrove jack Australia to northern New South streams and rivers to the extent of the tidal influence. Diet is Wales (DPI&F 2003). mostly fish and crustaceans (DPI&F 2003).

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Lutjanus russelli** Indo-West Pacific, in Australia Primarily a marine fish, adults occur on offshore coral reefs widespread in coastal areas from and inshore rocky and coral reefs. Juveniles mostly inhabit Moses perch Shark Bay, Western Australia mangrove estuaries and lower reaches of freshwater north to Queensland and south streams. Diet includes benthic invertebrates and fish to New South Wales (ABRS (Froese and Pauly 2009). 2009).

Carangidae Caranx sexfasciatus Indo-Pacific, in Australia Primarily a marine fish, adults occur in coastal and oceanic ** widespread in coastal areas from waters associated with reefs and occasionally enter rivers. Trevallies Shark Bay, Western Australia Juveniles may occur in estuaries sometimes entering rivers. Bigeye trevally north to Queensland and south Diet is mainly fish and crustaceans (Froese and Pauly to New South Wales (ABRS 2009). 2009).

Gerreidae Gerres filamentosus Indo-Pacific, in Australia Primarily a marine fish, adults occur in coastal waters with ** northern coastal waters from soft substrates and juveniles enter estuaries with Silverbiddies Exmouth, Western Australia to mangroves and sometimes fresh and tidal creeks till Threadfin silverbiddy northern New South Wales maturity when they return to sea. Diet includes (ABRS 2009). crustaceans, worms and insect larvae (Froese and Pauly 2009).

Sparidae Acanthopagrus Eastern and southeastern Estuaries, coastal rivers, creeks, lakes and bays, mostly in australis** Australia from North Queensland marine or estuarine waters. In dry seasons it moves into Breams to southern Victoria (Allen et al. lowermost reaches of freshwater systems (Allen et al. Yellowfin bream 2002). 2002).

Acanthopagrus Widespread in Indo-west Pacific. Mostly in estuarine waters of coastal rivers, creeks and berda** Northern Australia from Darwin inlets, occasionally moves into lower reaches of freshwaters to central Queensland (Froese streams (Froese and Pauly 2009). Pikey black bream and Pauly 2009).

Leiognathidae Leiognathus Indo-West Pacific, in Australia Primarily a marine fish, adults occur in shallow inshore equulus** northern coastal waters from coastal areas often in mangroves and into freshwater Ponyfishes Exmouth, Western Australia to reaches of rivers. Juveniles are commonly found in Ponyfish southern Queensland (ABRS mangrove estuaries and tidal creeks, sometimes entering 2009). This is the one species of the lower reaches of freshwater streams. Diet of small ponyfish that occur in Australia crustaceans, worms and small fishes (Froese and Pauly that is regularly encountered in 2009). fresh water (Allen et al. 2002).

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INTRODUCED SPECIES

Poeciliidae Poecilia reticulata Introduced to Australia, wild Various habitats, ranging from highly turbid water in ponds, populations established canals and ditches at low elevations to pristine mountain Live bearing Guppy throughout eastern and southern streams at high elevations. Inhabits slow-flowing or still Toothcarps Australia (DEEDI 2009) water near the margin of pools among vegetation. Has a wide salinity range but requires fairly warm temperatures and still vegetated water for survival. Feeds on zooplankton, small insects and detritus. Reproductive mode is entirely freshwater (Pusey et al. 2007, Froese and Pauly 2009).

Xiphophorus Introduced to Australia, in Creeks and swamps, warm springs, canals and ditches with maculatus Queensland present in many typically slow moving water, weedy banks and silt bottoms. coastal drainages around Feed on worms, crustaceans, insects and plant matter. Platy Brisbane and in the Wet Tropics Reproductive mode is entirely freshwater (Pusey et al. 2007, region (DEEDI 2009). Froese and Pauly 2009).

Cichlidae Tilapia mariae Introduced to Australia, present Still or flowing water in rocky or mud-bottom areas, in both Listed in Queensland as in the Barron River, the non-tidal and estuarine reaches. Reproductive mode is in a noxious fish. Cichlids Tilapia Mulgrave-Russell system and freshwater though there is some uncertainty whether it may the North and South Johnstone also occur in estuarine waters, spawns September-March Rivers system. (Pusey et al. 2007, DEEDI 2009). indicates species with strong marine or estuarine affinities that are also found in fresh water, ** indicate estuarine species.

Table 19: Estuarine Fish Species in the Mulgrave River

Family Name Species name Common name Comments

Eleotridae Butis butis Estuarine gudgeon

Clupeidae Sardinella sp. Herring

Gobiidae Yongeichthys nebulosus Estuarine goby

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Terapontidae Therapon jarbua Crescent perch

Mugilidae Liza subviridis Mullet

Liza vaigiensis Diamond scaled mullet

Valamugil seheli Blue-tailed mullet

Carangidae Caranx ignobilis Lowly trevally

Gerreidae Gerres abbreviatus Short silverbiddy

Leiognathidae Leiognathus decorus Ponyfish

Leiognathus splendens Black-tipped ponyfish

Secutor ruconius Pig-nosed ponyfish

Engraulidae Stolephorus sp. Anchovy

Synodontidae Saurida sp. Grinner

Platycephalidae Platycehpalidae sp. Flathead

Platycephalus fuscus Dusky flathead

Platycephalus indicus Bar-tailed flathead

Sillaginidae Sillago analis Golden-lined whiting

Sillago cilitata Sand whiting

Sillago sihama Winter whiting Sometimes found in freshwater (Allen et al. 2002).

Haemulidae Pomadasys kaakan Golden grunter

Pomadasys argenteus Small-spotted grunter

Mullidae Upeneus sulphureus Yellow goatfish

Monodactylidae Monodactylus argenteus Butterfish Regularly found in fresh water, though usually close to the sea (Allen et al. 2002).

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Ephippidae Drepane punctata Sickle-fish/batfish

Scatophagidae Scatophagus argus Spotted scat Commonly found in mangrove habitat and lower reaches of freshwater streams (Allen et al. 2002).

Siganidae Siganus lineatus Rabbitfish

Scombridae Scomberoides commersonnianus Queenfish

Bothidae Bothidae sp. Flouder

Pseudorhombus sp. Flounder

Cynoglossidae Cynoglossus sp. Tongue-sole

Tetraodontidae Spheroides hamiltoni Toadfish

Torquigener whitleyi Toadfish

42/15610/99537 Mulgrave River Aquifer Feasibility Study 94 Public Environment Report 5.7.4 Commercial and Recreational Fisheries The Mulgrave River catchment supports a multi-species recreational fishery (Russell et al. 2004), with a variety of habitats ranging from fast flowing freshwater streams of the upper catchment to swamps and the brackish waters of the lower estuary and Mutchero Inlet. Fish stocks are considered good (DPI pers comm Terry Vallance), however significant habitat has been lost in the valley, primarily due to clearing of riparian areas. Loss of riparian vegetation has allowed the invasion of weeds onto the banks and waterways, with increased erosion and discontinuous habitat. Pool to riffle ratio is used as a general indicator of stream habitat. Pools provide the habitat and riffles provide the food source – most often in the form of invertebrates. Studies have found that the ratio is generally 1:1 in the Mulgrave catchment (an indicator of high stream habitat values), however swamp and wetland areas, which are important sites for fish nursery, are continuing to decrease in number. The estuary is an important commercial prawn nursery and recreational fisheries for target species such as barramundi (Lates calcarifer) and mangrove jack (Lutjanus argentimaculatus) are well established in the river (Russell et al. 2004). Some of the aquatic habitat values are represented in intertidal and wetland areas. These areas are recognised as important fisheries nurseries, in particular being important for species of recreational and commercial significance such as barramundi, mangrove jack, mudcrabs, prawns, mullet and various other predominantly estuary orientated species. Of particular interest are three deepwater off-stream lagoons, referred to as the lower Mulgrave lagoons, remaining on the Mulgrave River immediately adjacent to the present course of the river upstream of Deeral Landing. These stranded lagoons (connected to the main river channel during normal wet season flow events) are regarded as high value fish nursery values. In the freshwater reaches of the Mulgrave River, above due east of Aloomba, there are numerous in- stream waterholes of varying depth that continue to have high fishery values for species such as sooty grunter, gudgeons, tandans, and other freshwater reliant species.

5.8 World Heritage and National Heritage Values Assessment of the environmental feasibility of the Mulgrave River Aquifer Scheme for this PER includes an assessment of the potential impacts of the abstraction on the World Heritage and National Heritage values of the Great Barrier Reef Marine National Park and the Wet Tropics of Queensland World Heritage Area (WTQWHA). The National Heritage values as listed by DEWHA for both the GBRMP and the WTQWHA are the same as the World Heritage values. Hence, any reference in this report to World Heritage values includes the National Heritage values.

5.8.1 Great Barrier Reef Marine Park The Great Barrier Reef World Heritage Area lies immediately off shore at the mouth of Mutchero Inlet. It also contains many outstanding examples of important and significant natural habitats for in situ conservation of species of conservation significance, particularly resulting from the latitudinal and cross- shelf completeness of the region. The World Heritage values include habitats for species of conservation significance within the 77 broadscale bioregional associations that have been identified for the property. The Mulgrave River is one of the major river systems that drain into the Great Barrier Reef Marine Park.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 95 Public Environment Report 5.8.2 Wet Tropics of Queensland World Heritage Area The Mulgrave River aquifer is bounded by the Wet Tropics of Queensland World Heritage Area to the east (Graham Range), to the west by the Bellenden Ker Range, and to the south by Mutchero Inlet. There are two areas of where the aquifer study area intersects the WTQWHA: - a small portion of the mid lower reaches of the Mulgrave River where approximately 700 m of the WTQWHA borders the eastern bank of the Mulgrave River, and the lower tidal section of the Mulgrave River at Mutchero Inlet. Whilst these two sections of the WTQWHA are within the study area, neither of these are within the actual aquifer. The Mutchero Inlet section is tidal and not underlain by the aquifer, and the small portion on the eastern bank of the Mulgrave River is on a spur of the Graham Range that intersects the river; the geology and hydrogeology characteristics are not derived from Mulgrave River alluvium, and also not considered to include the Mulgrave River aquifer.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 96 Public Environment Report 6. Construction Phase Impacts

6.1 Background Impacts arising from the implementation of the Mulgrave River Aquifer Scheme during construction will essentially only arise from the actual physical construction of the infrastructure (drilling activities, construction of the pump housing and associated water mains and electricity connections, pipeline network and mains connection to the existing Behana Creek water supply pipeline) and planning aspects related to land use planning within declared Groundwater Management Areas. These are discussed separately in the following sections.

6.2 Borefield Development Impacts

6.2.1 Vegetation Clearing It is intended to develop the borefield, based on current information, within the road reserve and public land areas within the general borefield development area (refer to Figure 3). This area is entirely cleared for sugar cane, and construction of the borefield will not require the clearing of any native vegetation community, nor any habitat areas for any flora species, being entirely grassed road reserves. The connecting water mains from each bore will be buried underground beside the roads, and there may be instances where isolated trees or shrubs in drainage lines that have not been cleared on road reserves, may be removed. A specific survey of the borefield area did not identify any species of conservation significance or any habitat values that would be adversely impacted by the construction of these water mains.

6.2.2 Erosion and Sediment Each bore site requires an area of approximately 10 m x 10 m for the bore housing, pump switch gear and connecting electrical supply from adjacent exiting powerlines. The pump itself is of a submersible electric type and will be located inside the bore (approximately 600 mm in diameter). The general borefield area is on flat to mildly undulating terrain, and earthworks required for the establishment of each bore site is expected to be restricted to the construction of the concrete pad for the bore housing (maximum of 3 m x 3 m). A construction Environmental Management Plan, based on the draft template provided in this PER, will be developed to manage potential erosion and sediment issues during construction.

6.2.3 Noise and Vibration During construction drill rigs will be operating during normal daylight working hours. The noise from the drill rigs will be temporary, and will not adversely impact wildlife. The nearest residence to the proposed borefield is approximately 80 m away and some minor inconvenience may be experienced during development of the borefield.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 97 Public Environment Report 6.2.4 Visual Amenity Pump houses are to be built for each bore. Pumps will be submersible types with electrical supply via overhead poles and lines into a concrete pump shelter. Pipes will be buried and concealed. It is anticipated that pump houses will be concrete and security fenced, with a total area of approximately 10 m x 10 m required for each bore. The visual impacts of the bore pump housings in a rural landscape will not detract from the scenic values of the Wet Tropics of Queensland World Heritage Area on either side of the Mulgrave River valley.

6.3 Social and Planning Construction Phase Impacts

6.3.1 Linear Severance Issues The borefield and associated delivery and treatment infrastructure are proposed to be located within road reserve and private property secured by Cairns Regional Council for the construction of the proposed infrastructure. It is not intended that any private land be acquired for the project, and implementation of the project will not alienate any agricultural land. There may be some impediment to movement of agricultural machinery on road reserve utilised as cane headlands. In a number of instances cane growing has extended into the reserve. In sites where this occurs and bores are to be developed then some loss of farmed land will occur. Another probable impact would be the incompatibility of urban development with the Groundwater Management Area (GMA). GMAs are declared by DERM, they are also referred to as subartesian areas. The Mulgrave River Aquifer Area south of Gordonvale is a declared Groundwater Management Area. The application of assessment policy means new developments proposed within the GMA will be subject to assessment under the planning scheme and the implications of the work will be subject to referral and concurrence from DERM. Certain types of landuse development, e.g. intense urban development, are not compatible with the intent of GMA and will not be permitted within the aquifer GMA.

6.3.2 Land Use Impacts The construction of Mulgrave River Aquifer Scheme has limited potential impacts on land use. The use of the Mulgrave River valley aquifer as a developed resource will likely preclude the use of the area for urban development. This may come into long term conflict with growing population pressures about regional centres south of the Mulgrave River, particularly Aloomba, Charringa, Deeral and Fishery Falls. However, urban development within the Mulgrave River aquifer GMA will not be in accordance with the existing policies of DERM who are currently an assessment manager or a referral agency under the Integrated Planning Act 1997 for any such development within a groundwater management area. Protection of groundwater resources are a key aspect that should be addressed in future regional planning.

6.3.3 Other Social Impacts There are no quantifiable cultural heritage impacts with the implementation of the Mulgrave River Aquifer Scheme. Cultural Heritage assessments will be required to be undertaken on a site specific basis when infrastructure planning and design is advanced, however there are no known cultural heritage values in the immediate vicinity or borefield, or infrastructure development areas. Known sites are restricted to the foothills, gorges and river systems within the adjoining WTQWHA outside the aquifer area and will not be

42/15610/99537 Mulgrave River Aquifer Feasibility Study 98 Public Environment Report impacted. Native Title has been deemed to have been extinguished for the freehold areas and road and highway reserves identified for this study. Native Title may be applicable to any other State Land that may be utilised in the future for infrastructure in locations that have not been identified in this report, e.g. if state forests or national parks are required for reservoirs or water treatment sites, then Native Title may be applicable to these areas.

6.4 Risk Assessment Matrices A preliminary risk assessment for the construction of the Mulgrave River Aquifer Scheme was undertaken. Table 20 represents the scored risk assessment matrices as supplied by Cairns Water and Waste (now Cairns Regional Council Water and Waste). CRCWW utilised the methodology in this report to arrive at the calculated risk levels.

The Risk Levels for the tables can be interpreted as: 1- 3.9 Low, 4 - 8.9 Medium, 9 -15.9 High, 16 - 25 Extreme. In general, CRCWW did not identify any high or extreme construction risks associated with the development of the borefield and supply infrastructure. Flooding and access to the construction site was considered to be the only potential risk during construction that could not be entirely mitigated.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 99 Public Environment Report Table 20: CRCWW, Summary Construction Risk Assessment, Mulgrave River Aquifer

INFRASTRUCTURE (construction)

Consequence Rating Likelihood Risk Level Aspect Element Description of Risk Maximum Average High Average

Pipelines Centralised Raw Trunk Failure of the Pipeline 2 1 1 2 1

Creek crossing 1 0 3 3 0

Construction of pipeline 2 1 1 2 1

Retic Trunk Failure of the Pipeline 2 1 1 2 1

Construction of pipeline 3 2 1 3 2

Flooding 2 1 4 8 4

Bore collection system Failure of an element of the 3 2 1 3 2 Trunk

Intake incl Structure Bore failure 2 1 1 2 1 structure

Flooding 2 1 3 6 3

Land Tenure 2 1 1 2 1

Pump Pump failure 2 1 2 4 2

Pipe Pipe failure 2 1 1 2 1

Power Supply Access to Power Cost 2 1 3 6 3

Flooding 2 1 1 2 1

Emergency Power Cost 2 1 1 2 1

42/15610/99537 Mulgrave River Aquifer Feasibility Study 100 Public Environment Report 7. Operational Phase Impacts

7.1 Background Operational use of the borefield has a number of potential impacts on social and environmental aspects. Primarily these include:

 Lowering of the groundwater level below that of the existing bores of land owners in the borefield area;

 Ground settlement;

 Intrusion of saline water into the groundwater and moving the saltwater interface in the Mulgrave River from its present position to further upstream;

 Exposure of acid sulfate soils in the lower reaches of the Mulgrave River as a result of diminished river flows arising from abstraction;

 Disruptions in river flow processes, altering erosion and sedimentation patterns; and

 Alteration to the flow regime of Mulgrave River and Behana Creek as a result of induced leakage from these systems back into the aquifer during abstraction.

7.2 River Processes and Interactions

7.2.1 Summary This study assessed the likelihood of contamination by saltwater intrusion, the potential for acid sulfate soils to be exposed, and the potential impact of reduced flows on river morphology and dynamics. Appendix D contains the Numerical Groundwater Modelling Technical Report which quantifies the impacts. Note that that report compares two abstraction scenarios: 40 ML/day, which is the ldaily limit corresponding to the licence allocation of 15,000 ML/day; and a constant rate of 15 ML/day. As mentioned previously, the proposed action under this PER relates to the 15 ML/day abstraction scenario. Details of the assumptions, caveats, cumulative impacts and level of scientific certainty are also presented in the Numerical Groundwater Modelling Technical Report provided in Appendix D. In overall terms, the model identified that the impact of abstracting 15 ML/day, constantly over 365 days in a year, will result in overall reduction of surface water flows of approximately 1% during low flow events in the dry season. This reduction when the area experiences three successive years where the rainfall was below average (three failed successive monsoon seasons) is approximately 4% of the base flow during low flow events in the dry season. The later scenario equates to an approximately 1 in 60 year event. These scenarios are based on constant abstraction rates of 15 ML/day for every day of the year and do not take into account the reality of operating the borefield as a supplementary water supply only. As has been previously noted, the borefield will be operated in accordance with demand requirements, with the borefield unlikely to be utilised for up to three months of the year during the wet season, and for the balance of the year abstraction to the full 15 ML/day allocation may only take place intermittently. Modelling of the abstraction regimes under differing stream flow characteristics identified that the development of the borefield and subsequent drawdown in groundwater levels will not result in the generation of any actual acid sulfate soil conditions in the aquifer area. Therefore, no acid runoff will be

42/15610/99537 Mulgrave River Aquifer Feasibility Study 101 Public Environment Report generated by the aquifer scheme. The likelihood of saline water being introduced into the aquifer as a result of abstraction has been identified as being non quantifiable. The numerical groundwater modelling identified that the potential risk of salt intrusion into the aquifer was identified as absent under all conditions for the proposed abstraction of 15 ML/day. Reduced river flows (by 1%) during the normal dry season are unlikely to result in impacts on river morphological processes, particularly sand and gravel movement and maintenance of connecting riffles. During extended dry season low flow events (one in 60 years) there is a potential that a 4% reduction in river base flows as a result of the abstraction may have minimal impacts on river processes.

7.2.2 Interaction of the Aquifer with Mulgrave River and Behana Creek Within this section is a qualitative description of how the Mulgrave River Aquifer Borefield operation may interact with the Mulgrave River and Behana Creek and surrounding systems. Figure 12 shows the location of the Mulgrave River Aquifer and the proposed bores in plan view relative to the Mulgrave River and Behana Creek, together with the general groundwater flow directions either side of the flow divide to the north of Gordonvale.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 102 Public Environment Report Groundwater Divide

Borefield Area

Groundwater Flow directions

Figure 12: Groundwater Flow Directions

42/15610/99537 Mulgrave River Aquifer Feasibility Study 103 Public Environment Report The description of the aquifer and rivers within the Mulgrave River valley provided in Section 4.3 is shown schematically in Figure 13 for the intermediate/lower reaches of the Behana Creek and the Mulgrave Aquifer.

Mulgrave River Valley Mulgrave Intermediate Reach Upper Reach

Borefield Behana Inter Area and Lower Reach Fan deposits Current Mulgrave River Floodplain

Figure 13: Mulgrave River Valley

The description of the interaction between Behana Creek, Mulgrave River and the aquifer needs to consider seasons of the year (wet season versus dry season) and also the upper, intermediate and lower reaches of each Creek or River. The upper reaches of Behana Creek and Mulgrave River are situated upon an elevated hard rock terrain wherein a high proportion of rainfall runs off as stream flow. As these sections occur within the ranges topographically above the Mulgrave River floodplain, the upper reaches only contribute to downstream flow as a result of rainfall on the range above. The intermediate and lower reaches of Behana Creek and the intermediate reach of Mulgrave River occur where these surface systems traverse the upper sections of the Mulgrave River overlying the aquifer found within the Quaternary alluviums. The intermediate reach of the Mulgrave River also exists within the relatively recently formed Mulgrave River Floodplain. During the wet season, Behana Creek and Mulgrave River act as strip filling systems into the Mulgrave River aquifer system until such time as the valley sediments and the floodplain receives sufficient rainfall or direct runoff to elevate the extent of stored groundwaters (shallow and deeper aquifers) across the floodplain such that the Mulgrave River then acts as a drain for the floodplain. This is illustrated schematically in Figure 14. This situation is maintained until such time as the overall stored groundwaters have "drained" to the level set in relation to the coastal saline water interface. This drainage response is “dampened” in relation to the water transmission characteristics of the aquifer along the flow path.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 104 Public Environment Report Wet Season Free Water Surface, Upflow to River and down Standing Water Level River Flow: River Gains BEHANA CREEK

MULGRAVE RIVER

Flow from Behana to the groundwater systems: Creek Losing

Down Valley Flow: Note down valley flow also in the Tertiary Aquifer

Figure 14: Wet Season: River to Aquifer Interactions

The lower reaches of the Mulgrave River (near Deeral), acts as a drain and outlet for flows from upstream to exit to the ocean above the prevailing sea level. During the “wet” this pushes the saline interface further downstream, while during the dry when the volume of water "draining" from upstream reduces, the saline interface will move further upstream, closer to the actual level of the tides, i.e. around the 2 m AHD land contours. As the year dries down the free water level declines and should the dry down continue long enough the regional groundwater level will fall below the base level of the Mulgrave River at which time, ponded waters in the river will then flow to the groundwater systems. This is shown schematically in Figure 15. The effect of pumping on the overall water stored in the aquifer is a localised lowering of the groundwater levels to support the pumping. The extent of this lowering is a function of the relative “water yielding” characteristics of the aquifer materials. Outside of the present Mulgrave River floodplain we find the aquifer is much more sandy and gravelly than within the floodplain, which tends to be more silty and clayey. The sandy gravelly material of the Mulgrave River Valley Aquifer will provide water to the bores more readily than the floodplain clayey sands, which in turn has the affect of altering usual dry season standing water levels in the floodplain to a lesser extent than it does for the standing water levels outside the floodplain within the valley alluvial systems. In the context of the overall study area, all rainfall falling within the catchment must eventually leave the catchment as either river flow via the Mulgrave River, groundwater flow across the lower Mulgrave River reach and saline interface zones, or through environmental and anthropogenic use (bores, river pumping, etc).

42/15610/99537 Mulgrave River Aquifer Feasibility Study 105 Public Environment Report Bores Late Dry Season, Standing Water Level: No Pumping BEHANA CREEK Early Dry Season

MULGRAVE RIVER

Localised Groundwater capture zone feeding the Borefield Pumps

Altered Standing Water Level: Late Dry with Borefield Pumping. Down Valley Flow continues

Figure 15: Dry Season Interactions and Drawdown Conceptually therefore, there must be a balance between what water is added to groundwater storage relative to that taken out, with this balance being determined at the study area boundaries. This balance is a function of the rainfall, the extent of overland flow, the amount of storage available in the groundwater systems and the time between fills and drawdown. However, this balance has a time dimension of several years and a spatial dimension of approximately 800 square kilometres. Within the time dimension we know there are series of wet, dry, extreme wet and extreme dry years. On average the groundwater system contributes approximately 30% of the annual average river flow volume through the river gaining from the recharged groundwater system along its length. It is also known that within the 800 square kilometres, some areas more readily accept water than others, such as the gravelly sands as opposed to the silty clayey sands of the floodplain. Areas that also “yield” the captured waters more readily than others have also been identified. Within the overall Mulgrave River Valley system water balance, any alteration to the present rate of groundwater extraction must be supported by a reduction in the surface water flow. This is a volumetric relationship of balance that is maintained across the study area and is achieved over a number of years relative to the seasonal variability of the inputs (rainfall, floods, droughts) and outputs (evaporation, transpiration, bore pumping and discharge to the ocean). The present extent of river flow is on average approximately 770,000 ML/year. The estimated extent of river flow from “captured” groundwater is approximately 200,000 ML/year, representing less than 30% of that occurring within the catchment. Of this approximate 30% of flow contribution arriving through groundwater discharge from the aquifer systems to the Mulgrave River, the proposed abstraction of 15 ML/day or 5,500 ML/year, if pumped for 365 days/year, equates to less than 2% of the net annual groundwater contribution to river flow.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 106 Public Environment Report 7.2.3 Surface Flow Impacts The numerical groundwater modelling identified that for six months of the year (the wet season), under nearly all variability identified in the gauging station data, the Mulgrave River is accepting the excess recharge of the aquifer. That is, the aquifer becomes completely saturated and the overflow feeds directly into the Mulgrave River and Behana Creek, sustaining very high volume surface flows during the typical wet season from January to April. The numerical groundwater model has also identified that during the dry season, there is ‘leakage’ from these systems into the aquifer. This is a function of the enormous variability in the seasonal flow of the water courses, with the Mulgrave River having one of the proportionally highest annual variance in river flows for Australian rivers. The modelling of the prospective impacts has therefore been restricted to an analysis of dry season impacts, as the proposed abstraction from the Mulgrave River aquifer (for all scenarios up to the maximum allocation of 15 ML/day) will NOT impact on the flows of the Mulgrave River during the wet season as the borefield will not be in operation. To further refine the impact assessment, an analysis was performed on the river for the driest seasons on record, June 2001 to November 2003. These years typically represent a 1 in 60 year dry season event for the river (i.e. represents conditions after three consecutive below average rainfall years), and the use of these years’ data was to enable a conservative approach to the calculation and maintenance of environmental flows. Similarly, demand usage data was not available at the time of the initial assessment, and demand was modelled on the full abstraction rate of 15 ML/day, 365 days of the year based on 12 hours on, 12 hours off pumping in each 24 hour period. The abstraction, as modelled, will result in a less than 1% impact on surface flows (or 4% for the 1 in 60 year dry season event). In consideration of the conservative limits in the model, the practical impacts of the abstraction on the surface flows of Mulgrave and Behana will be less than that modelled (i.e. impacts could be considerably less).

7.2.4 Potential Saltwater Intrusion Saltwater intrusion impacts have been assessed by consideration of two conditions. Firstly, altering the “tidal wedge” characteristics of the Mulgrave River, in which the saline effect of tidal water is exerted further upstream in the river than what currently exists. Secondly, in terms of the potential for saline water to contaminate the aquifer. The prediction from the numerical groundwater modelling is that neither case will occur under any conditions of the proposed abstraction rate of up to 15 ML/day. No impacts from saltwater intrusion are anticipated on any natural feature of the aquifer. The groundwater modelling has identified that the proposed abstraction (15 ML/day) drawdown is not predicted to significantly affect the saline groundwater interface and there is a low to no risk of inducing saline intrusion into the aquifer. The numerical groundwater model identified that a 1% reduction in base flow under normal climatic conditions would not amplify the tidal influence/extent of the Mulgrave River.

7.2.5 Modification of River Processes Natural river processes are dependent on a range of inputs, and in the Wet Tropics, these morphological processes, which include erosion and sediment deposition patterns, are largely governed by the intensity

42/15610/99537 Mulgrave River Aquifer Feasibility Study 107 Public Environment Report of river flows. The Mulgrave River has one of the largest ranges of river flow in the region, with an extensive catchment that includes mountainous areas that may receive in excess of 8 m of rainfall in a year. Consequently, flows can fluctuate widely and this flow variation has been responsible for the shaping of much of the Mulgrave River in the study area. High flow events during the wet season are the predominant shaping forces of the middle and lower reaches of the Mulgrave River. These high flow events define the river channel, the bed of the river and other physical attributes of the instream characteristics of the river. During the wet season it is unlikely that the borefield would be in operation. However, given the very large flow of the Mulgrave River and Behana Creek during the wet season, river morphological processes will not be affected even if abstraction occurs. During the dry season, flows in the Mulgrave River and Behana Creek are significantly less than wet season flows. In many areas these systems are reduced to deep sandy pools connected by shallower areas of cobbled bed. River shaping processes are consequently much reduced due to the absence of power in the stream. Low flow events however, are equally as important as wet season flows, particularly in the creation and maintenance of freshwater riffle zones, and maintenance of aquatic microniches for benthic dependent organisms The majority of the most obvious morphological processes of the Mulgrave River and Behana Creek occur during wet season flows when abstraction is not expected to occur. If it does occur the quantifiable impacts are negligible owing to the extremely high volumes of surface flow during this period. Major erosion and sediment deposition processes during these flows characterise the most obvious morphological features of the waterways. Less obvious morphological structures, such as bed deposition and particle size distribution, riffle zones and sandbar maintenance, are reliant on base flows outside of the wet season. The abstraction of up to 15 ML/day from the aquifer will reduce surface flows by approximately 1% during the average dry season, and by up to 4% during extended dry periods (1 in 60 year occurrence). Operation of the borefield will be subject to a detailed Borefield Operation Plan, which will have operational rules identifying thresholds and triggers for action in relation to minimising impacts on river flows. An impact of 4% during extended dry periods is unlikely to have a quantifiable impact on river and stream processes, based on the data available. However, in combination with a Borefield Operation Plan, the impacts on river flows will be much lower than the modelled 4% during the extended dry season, and no adverse impacts are expected from the operation of the borefield under the proposed management and mitigating measures.

7.2.6 Potential Acid Sulfate Soil Exposure Acid and toxic concentrations of metals can be released into the environment when acid sulfate soils are exposed to air and become oxidised. Groundwater abstraction in areas containing acid sulfate soils such as Trinity and Mutchero Inlets has the potential to lower the water table such that these materials become exposed to air. Subsequent recharge may release these contaminants to the marine or freshwater environment. Aquatic flora and fauna are particularly vulnerable to changes in the concentrations of metals and acids that will be generated when acid sulfate soils are exposed. Mass death of fish and aquatic invertebrates is a common feature of acid sulfate soil generated contaminants reaching natural surface waters.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 108 Public Environment Report The predicted drawdown at the maximum abstraction levels (15 ML/day) does not extend to areas of acid sulfate soils or the significant ecological communities at either Trinity Inlet or Mutchero Inlet (refer Appendix D for the Numerical Groundwater Modelling report).

7.3 Cultural/Social Assessment

7.3.1 Summary The operation of the Mulgrave River aquifer scheme has limited potential impacts on cultural and social values. The use of the Mulgrave River valley aquifer as a developed resource will likely preclude the use of the area for urban development. This may come into long term conflict with growing population pressures about regional centres south of the Mulgrave River, particularly Aloomba, Charringa, Deeral and Fishery Falls. However, urban development within the Mulgrave River aquifer groundwater management area would not be in accordance with the existing policies of the Department of Environment and Resource Management who are currently an assessment manager or referral agency under the Integrated Planning Act 1997 for any such development. Protection of groundwater resources are a key aspect that should be addressed in future regional planning. Furthermore, the Mulgrave River Aquifer Area is not within the urban footprint of the Far North Queensland Regional Plan 2009-2031 (note that there is Aloomba is mapped as urban footprint). The Mulgrave River Aquifer Scheme will limit the number of future bores and/or allocations within the groundwater management area of the aquifer. It should be noted that DERM currently have allocated 7,000 ML/year for irrigation and domestic supply purposes within the Mulgrave River aquifer, predominantly north of the Mulgrave River. The majority of existing and unused allocations may be utilised without any impact from the aquifer scheme. There is only one registered private bore that numerical modelling indicates will be impacted by the operation of the borefield. It is proposed the the identified bore be deepened to manage this impact. There are no quantifiable cultural heritage impacts with the implementation of the Mulgrave River Aquifer Scheme. There are no cultural heritage listed wetlands on the register or database of the Queensland Aboriginal Cultural Heritage Management Act 2003 within the study area of the Mulgrave River aquifer. Cultural Heritage assessments will be required on a site specific basis when infrastructure planning and design is advanced. However, there are no listed cultural heritage values in the immediate vicinity, the borefield, or the infrastructure development areas. Known sites are restricted to the foothills, gorges and river systems within the adjoining WTQWHA that are outside the aquifer area and will not be impacted. Native Title has been deemed to have been extinguished for the freehold areas and road and highway reserves identified for this study. Native Title issues will be addressed during the Phase 2 investigations for infrastructure that may be located on any other State Land that may be utilised in the future.

7.3.2 Affected Land Use and Land Settlement The numerical modelling identified that one existing registered bore will be impacted by operation of the borefield at its maximum proposed abstraction of 15 ML/day. The combined total annual allocation of the bore is 2 ML. In the absence of recorded depths, it was assumed in the modelling that the depth of the existing bore was 10 m below the mapped groundwater elevation at these locations. The impacts on the affected bore are presented in Table 21.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 109 Public Environment Report A land consolidation analysis has been completed as part of the numerical modelling analysis documented in Appendix D. In summary, the modelling predicted that in the maximum drawdown scenario, settlement would be up to 0.03 m (or less than 3 cm) over the broader area. Land consolidation is anticipated to be relatively uniform, to occur gradually over several years and not to affect any infrastructure, including residences, road and road structures (drains, bridges) in the area. Approximately one third of the total settlement depth will occur immediately in response to groundwater drawdown, while the residual settlement will occur over a longer period of time. The results indicate that there will be minimal to no quantifiable impacts in the area.

Table 21: Summary of Potential Landuse Impacts

Land Use Impact Abstraction 5,500 ML/year (15 ML/d)

Maximum Drawdown (m) 2

Extent of 0.5 m Drawdown (km) 3

Number of Bores Affected 1

Total Licensed Volume of Affected Users (ML/year) 2

Settlement (m) 0.03

Drawdown at Saline Interface (m) 0

7.3.3 Noise and Visual Amenity Operation of the borefield will be almost silent. The pumps are electrical pumps, and are of a submersible type that will be placed within the bore itself near the groundwater level. The only noise will be evident immediately adjacent to the bore housing, comprising mainly the sound of electrical switch gear in operation and the sound of water flowing out of the bore into the water pipeline. The water pipelines will be buried and will be totally inaudible when water is flowing through them. As previously mentioned the bores will be housed in a small concrete enclosure within a security fenced area of approximately 10 m x 10 m and a connecting powerline to the existing powerline network in the borefield area. The small number of these (up to 10 bores) will not detract from the rural setting of the local area, and will not adversely impact the scenic values of the adjacent Wet Tropics of Queensland World Heritage Area.

7.3.4 Commercial and Recreational Fishing The Mulgrave River and Mutchero Inlet are high profile key recreational fishing areas in North Queensland, with ready access and a high diversity of species contributing to the popularity of the river and inlet. Commercial fishing is no longer undertaken in the Mutchero Inlet (within the WTQWHA). However, the inlet is recognised as a critical nursery area for many species of commercial significance (e.g. prawns, crabs, barramundi), which are taken commercially outside the immediate area. The majority of the recreational fishing is undertaken in the tidal reaches, with target species typically including barramundi, grunter, bream and mangrove jack. Occasional pelagic species such as trevally are taken in the estuary, and king salmon are important on a seasonal migratory basis. Mud crabs are also taken throughout the tidal sections of the river. The major fish species are primarily estuarine species, none of them being entirely freshwater dependent excepting for portions of the life cycles of

42/15610/99537 Mulgrave River Aquifer Feasibility Study 110 Public Environment Report some, such as barramundi. The majority of the species migrate freely between the lower and middle reaches of the Mulgrave River under normal climatic and flow conditions with occasional incursions further upstream. The proposed abstraction at the nominated levels has no modelled quantifiable impacts on environmental flows of the Mulgrave River and Behana Creek and commercial and recreational fish stocks would not be impacted. Fish will still be able to migrate freely between the various reaches of the Mulgrave River, and impositions on their migration and habitat utilisation would remain dependent on existing dry season base flows. During the wet season there are no restrictions on fish movements. Similarly with boating movements, typically movement barriers would be caused by the greater exposure of sand bar obstructions and the creation of shallower riffles interconnecting the major pools of the mid to upper reaches of the Mulgrave River. The mid to lower reaches of the Mulgrave River are tidally dependent and sand bars are not regularly exposed in these areas. However, with no impacts during the wet season, and only up to 1% impact on surface flows during the average seasonal year (increasing to 4% during the 1 in 60 year dry season event), boating access to the Mulgrave and Behana systems is expected to remain as it does currently.

7.3.5 Cultural Heritage Values and Native Title Implications The development of Mulgrave River Aquifer Project will have no known impacts on Cultural Heritage Values. A search of the Cultural Heritage Register and Database identified that the nearest Cultural Heritage records are within the WTQWHA adjoining the aquifer area, with no records within any of the proposed infrastructure development areas. These records are primarily within the Russell River catchment, and lower Mutchero Inlet on the seaward side of Russell Heads and the Woolanmaroo area (north of the mouth of the Mulgrave River on the coast). No known sites will be affected. Not withstanding, CRCWW have a Duty of Care obligation under the Queensland Aboriginal Cultural Heritage Act 2003 to ensure that any development works do not knowingly impact on items of Cultural Heritage significance. The proposed borefield and infrastructure development areas are intensely farmed sugar cane, or comprise road and rail reserves, mostly devoid of vegetation. The only area where additional care may be taken is if there is potential clearing of vegetation and associated earthworks at the location nominated for the balancing storage and pump station (i.e. the existing Gordonvale waste transfer station owned in freehold by Cairns Regional Council). A site clearance from a traditional owner would ensure that Duty of Care guidelines have been observed if vegetation clearing and earthworks are required. It should be noted that groundwater is regarded of Cultural significance under the provisions of the Queensland Aboriginal Cultural Heritage Act 2003 where groundwater is responsible for the maintenance of wetlands, springs and swamp areas listed under the Cultural Heritage Register and Database. There are no cultural heritage listed wetlands in the project area. Areas such as Tanners and Gallett’s Lagoon downstream of the predicted drawdown of the aquifer abstraction (refer Appendix D) are not listed wetlands of cultural heritage significance. The wetland areas of nearest listed significance (Woolanmaroo and Eubanangee Swamp complex of the lower Russell River) are not within the Mulgrave River catchment. The Mulgrave River aquifer does not interact with these systems, and the lower wetlands and swamps that previously existed in the lower Mulgrave have been cleared, drained and are now extensive cane fields. The groundwater resources of the Mulgrave River aquifer are not considered significant in maintaining any area of cultural heritage significance in the project area. Mutchero Inlet is

42/15610/99537 Mulgrave River Aquifer Feasibility Study 111 Public Environment Report tidal, and freshwater inputs are derived from the Russell River, Mulgrave River and from the substantial subsurface flows and minor streams from the nearby Bellenden Ker Ranges. Native Title is deemed to have been extinguished over all the areas proposed for the development of the borefield and infrastructure. The majority of this land is either freehold, or is road/rail reserve where Native Title has been extinguished. Native Title determination exists for the adjacent WTQWHA, however this will not impact on the development of the project.

7.4 Habitat Integrity and Availability

7.4.1 Groundwater Dependent Ecosystems The Mulgrave River Aquifer Area is generally demarcated by the extent of alluvium deposition in the river valley, approximating the 20 m topographic contour line. Within this boundary, the Mulgrave River valley has been extensively cleared, with less than 10% of the original vegetation remaining primarily as a discontinuous band of riparian vegetation on the Mulgrave River and tributaries. Interaction between surface water and groundwater is an important aspect of the Mulgrave River aquifer water balance. Numerical groundwater modelling shows that abstraction of up to 15 ML/day has a predicted impact on the river base flow during the average dry season of approximately 1% or as modelled for an extensive dry period (three consecutive dry years, a 1 in 60 year event) of up to 4% of base flows. Consequently, no impacts on environmental flows are anticipated at all during the normal seasonal year. During dry season events (as defined by climatic data, groundwater levels and river flows) borefield operation will be managed to ensure that impacts are commensurate with maintenance of environmental flows within the river systems. There are two distinct groundwater dependent ecosystems in the Mulgrave River aquifer, one which is an obligate riparian ecosystem reliant on a combination of groundwater/surface interactions (i.e. vadophytic ecosystems) and the other an entirely groundwater dependent system (i.e. phreatophytic). The first is the representative riparian vegetation of the Mulgrave River and tributaries, consisting of a mosaic of vegetation (mostly rainforest) communities with distinctive species assemblages. These riparian communities are seasonally groundwater dependent, accessing groundwater resources during prolonged dry periods. The typical constituent canopy trees of these riparian communities are often deep rooted and are able to tap into the groundwater resources under dry conditions. Many of the smaller tree and shrub species (such as Pseuduvaria mulgraveana var. mulgraveana) with shallower root systems are stressed during prolonged dry periods, with symptoms such as reduced seedling recruitment, leaf drop and advanced senescence (i.e. ageing) and aborted flowering/fruiting etc. Extreme periods may result in the death of individuals. The abstraction of 15 ML/day and reduction of river flows by 1% during the normal seasonal year (and up to 4% during three successive dry years of failed monsoon seasons) is not expected to have any quantifiable impacts on vadophytic ecosystems (i.e. riparian ecosystems reliant on a combination of groundwater / surface water interactions). The second are the obligate groundwater phreatophytic systems (palm/tea tree swamps) to be found in the vegetation communities of the lower Mulgrave River, adjacent to Mutchero Inlet, and extending a short way up the Mulgrave River into the aquifer study area. These typically include feather palms, melaleuca (paperbark or tea tree) swamps or mosaics of these types interspersed with rainforest species. Two types of feather palm swamp wetland occur in different positions along the Mulgrave River (Stanton and Stanton, 2004, Small 1999), a mixed freshwater mangrove/feather type in the middle

42/15610/99537 Mulgrave River Aquifer Feasibility Study 112 Public Environment Report reaches of the Mulgrave River, and a more rainforest complex feather palm community in alluvial areas in the lower reaches of the Mulgrave River. Of these two groundwater dependent communities, the freshwater mangrove (Barringtonia sp) feather palm variant is considered to be most at risk as it is in a riparian situation directly reliant on the base flows of the Mulgrave River. Owing to the position of this community being within the predicted zone of influence of the drawdown in the aquifer, and being located on low lying river aggregates, it is more at risk from changes in river base flow than other communities in the study area. It is highly likely that the predicted impact of abstraction on 1% of the river flow will not affect this community, but confidence is less sure during the extended dry season events (1 in 60 year occurrence) where surface flows may be reduced by up to 4%. Current scientific literature on environmental flows suggests that reductions of base flows in excess of 5% during dry seasons may induce adverse environmental effects. The reduction of base flow by 4% is close to this figure. As a precaution, further investigations have been commissioned by Cairns Regional Council Water and Waste to refine the predicted impacts based upon actual borefield operational requirements and improvements to the modelling of the surface water and groundwater interaction. A second feather palm swamp wetland type is more complex than the above, and frequently intergrades with rainforest and paperbark species in the lower reaches of the Mulgrave River, usually on areas of alluvium away from the main channel. These primarily occur in the lower reaches of the Mulgrave River near Mutchero Inlet, and are more often on the landward side of the intertidal zone. These areas are tidally influenced; however they are primarily maintained by freshwater seepage and springs from the foot of Malbon Thompson Range, and not directly from the Mulgrave River aquifer. Consequently, its presence in saline influenced areas is made possible by the surface water runoff from the Malbon Thompson Range ameliorating the intertidal saline conditions. Feather palms have very shallow root systems (less than 2 m) that are incapable of reaching any groundwater at depth, and are not considered to be groundwater dependent on the resources of the Mulgrave River aquifer in the landscape positions in which they occur. In the Mutchero Inlet area, at the junction of the Russell/Mulgrave Rivers, the juxtaposition of the communities to the Bellenden Ker Range (which receives in excess of 9 m of rainfall in a year), allows recharge of the communities by shallow subsurface flows from this range and enables these palm communities to survive in tidal conditions. The abstraction of water from the Mulgrave River aquifer in accordance with a schedule to maintain environmental flow will not change this relationship and will not impact on the groundwater dependent communities described above.

7.5 Environmental Flows The Mulgrave River has one of the highest proportional variances between dry season and wet season flows in Australia (former DNRW, gauging station database). Consequently, this represents considerable challenges in attempting to establish environmental flow benchmarks for the Mulgrave River and Behana Creek (the major tributary within the aquifer portion of the river catchment). The majority of environmental flow methodologies and models in use in Australia until quite recently have been based on southern Australian and southeast Queensland rivers, which have extremely different aquatic, morphological and hydrodynamic processes and attributes by comparison with tropical rivers, particularly in north Queensland.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 113 Public Environment Report Environmental flows are important to different aspects of the Mulgrave River at different times of the year. The risk assessment is based on a hydrological Level 1 assessment commensurate with an initial feasibility investigation and acknowledges that further investigations will be required as part of assessments for state government approvals. The caveats, assumptions and limitations of this approach are detailed in the Numerical Groundwater Modelling Report in Appendix D. The risk assessment of likely/potential impacts of altered environmental flows on the Mulgrave River and Behana Creek considered the following primarily in relation to the Matters of National Environmental Significance as referred to in the Guidelines for this PER. Other matters of local, regional and state significance will be considered in the development of more detailed environmental flow assessments. The risk assessment on matters of NES considers:

 maintenance of groundwater dependent ecosystems;

 maintenance of river morphological shaping dynamics and processes;

 maintenance of instream aquatic health and ecology;

 potential for saline intrusion into the groundwater;

 potential for the exposure of acid sulfate soils;

 impacts on distribution and abundance of feral animals/plants (notably tilapia, pond apple and Hymenachne); and

 reduction of freshwater flows into the Great Barrier Reef Marine Park lagoon

7.5.1 Hydrological Environmental Flow Assessment At present, there is insufficient information in the form of flow data from the middle and lower reaches of the Mulgrave River and from Behana Creek to accurately establish an environmental flow benchmark and to further calibrate the existing numerical groundwater model. Therefore the assessment of environmental flows has used flow data from the Gordonvale gauging station on the Mulgrave River, which is known to underestimate dry season flows as during low flow events the river bypasses the gauging station which is located in the Mulgrave Mill pump house. On an equally conservative basis, the impact assessment is based on the use of 10% of the 80th percentile flows, rather than the more widely used 30% of the 80th percentile flows in other parts of Queensland and Australia. The environmental flow calculations are shown in Table 22. Essentially the 10% figures indicate the volumes of water that can be lost from the Mulgrave River before environmental flows are affected. This is a coarse hydrological assessment, and subject to the appropriateness of utilising hydrological models derived elsewhere in Australia to wet tropical systems such as the Mulgrave River catchment. For the critical dry months, the 80th percentile flow in the Mulgrave River is 590 ML/day, suggesting an allowable abstraction of 59 ML/day most of the time. An abstraction of 15 ML/day will have the impact of river flows of approximately 2.5% of the minimum 80th percentile. Considering these impacts in terms of absolute values, an aquifer abstraction of 15 ML/day would reduce river flows by 1% during the dry season of a normal climatic year, and not have any quantifiable impact during any wet season. During the maximum dry season event (as identified from 90 years of climatic data), there is a 1 in 60 year event where three successive dry years result in very low river flows.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 114 Public Environment Report Modelling of this scenario indicated that abstraction would reduce stream flows by up to 4% during this extreme dry season event. It is noted that these calculations are based on groundwater models that have assumed a conservative approach to the calculation of impact on flow in the river (refer to Appendix D for details of caveats and assumptions). Based on discussions with DERM (Water Accounting and Management) staff, during which reference was made to their operational procedures, it is understood that stream flow cannot be determined to an accuracy of more than +/- 5%, even in controlled conditions with devices such as a V-notch weir. Indeed, given the natural characteristics of the Mulgrave River, such as a moving bed and irregular cross sectional profile, it is not expected that stream flows will be able to be determined to within +/- 10%-15%. Hence the predicted reduction in stream flow due to the aquifer abstraction is not expected to be accurately measured in the river. Intuitively, based on the above assessments, and recognising (when compared to temperate streams in Australia) the greater variability in flow conditions in tropical rivers, it is considered that the aquifer abstraction of 15 ML/day is unlikely to have any unacceptable adverse impacts on the Mulgrave River ecosystems. The above assessment does not take into account detailed ecological information, or reflect the actual operating parameters of the borefield. Notwithstanding the above conclusion, of the absence of unacceptable adverse impacts, CRCWW is undertaking a program to collect this information as part of ongoing refinement of the aquifer model.

Table 22: Environmental Flow Calculations

Wet Season Post Wet Season Dry Season

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Daily Average 80th 5540 7661 4790 2664 1656 1313 1052 826 586 696 1137 2809 Percentile Flow

Allowable loss at 10% of the 80th 554 766 479 266 166 131 105 83 59 70 114 281 percentile (ML/day)

Stream abstraction at 0.27 0.19 0.31 0.56 0.91 1.14 1.43 1.81 2.56 2.16 1.32 0.53 15 ML/day as % % % % % % % % % % % % percentage of 80th Percentile Flow

7.5.2 Behana Creek Environmental Flows Potential impacts of the abstraction are not evenly distributed between Behana Creek and the Mulgrave River. As a proportion of total flow, Behana Creek loses more water to the aquifer during abstraction than the Mulgrave River, and impacts on Behana Creek are likely (for all abstraction scenarios) to be more amplified than for the Mulgrave River. The modelling outcomes in the numerical groundwater model (Appendix D) considers that impacts will be similar to stream flows in both systems. To mitigate against potential impacts to these waterways, the Borefield Operation Rules will address management strategies in regards to the Mulgrave River and Behana Creek systems separately.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 115 Public Environment Report 7.5.3 Nature of Possible Impacts on Freshwater and Intertidal/Marine Environments The majority of the fish in the Mulgrave River are summer (wet season) spawners, not winter (dry season spawners). A number of important prey species such as rainbowfish, gobies, Pacific blue-eyes, etc and commercial/recreational species such as barramundi occur in the Mulrgave River. During the summer months flows of the Mulgrave River and Behana Creek are very high. Groundwater modelling has indicated that during these high flow events (corresponding to the fish spawning patterns of most fish species) abstraction will not impact on the modelled environmental flows of the Mulgrave River/Behana Creek systems. The cardinal fish (mouth almighty) and two endemic gobys to the Wet Tropics region, the Mulgrave River goby and scaless goby, are thought to spawn in the drier months of the year. Although available literature regarding their reproductive biology is limited, it appears that stream flows during the dry season are relevant to their spawning cycles. Fish that inhabit the Mulgrave River can tolerate a wide range of environmental conditions. It is unlikely that a significant impact to suitable habitat will occur as a result of the proposed works. Overall it is predicted that abstraction levels (under average climatic conditions) would have no quantifiable impacts (and minimal general impacts) on freshwater or intertidal/marine environments.

7.6 Flora of Conservation Significance

7.6.1 Mangrove Orchid (Dendrobium mirbelianum) Dendrobium mirbelianum was not identified during the surveys, and there are no recorded sightings on available databases. Whilst potential habitat for the species is present within the intertidal mangrove swamp areas of the lower study area, it is unlikely that the species is present. This area is subject to regular tidal influences and would not be affected by changes in river flows that may result from abstraction in the aquifer. The species is an epiphyte, usually found on marine plants such as mangroves, which are not dependent on the freshwater flows from the Mulgrave River. The potential host trees (mangroves) are not sustained by groundwater from the Mulgrave River aquifer and are not groundwater dependent ecosystems. The potential risk of the project to adjacent habitat of this species is not quantifiable.

7.6.2 Blue Orchid (Dendrobium nindii) There is the potential that suitable habitat for D. nindii is present in the intertidal mangrove swamp areas of the lower study area, however it was not identified during field surveys nor is it present on any databases as having been observed or collected within the study area. The potential habitat area is subject to regular tidal influences and will not be impacted by abstraction from the Mulgrave River aquifer. The host trees (mangroves) are not sustained by groundwater from the Mulgrave River aquifer and are not groundwater dependent ecosystems. The potential risk of the project to adjacent habitat of this species is not quantifiable.

7.6.3 Eleocharis retroflexa The species is a freshwater water swamp species, growing within groundwater dependent ecosystems. Freshwater sedge swamps are not present in the Mulgrave River Aquifer Area, these swamps all having been historically drained for cane farmland. Suitable habitat (and all known records of the species) is known from the adjacent Russell River catchment and these areas will not be impacted by the project.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 116 Public Environment Report 7.6.4 Layered Tassel Fern (Huperzia phlegmarioides) This is an epiphytic fern, usually found growing within rainforest canopy tree species. No clearance of rainforest vegetation will occur as a result of the project. It is not expected that any changes in groundwater availability will affect the survival of either this species, or its host rainforest trees.

7.6.5 Other Species During the field investigations incidental observations of species listed under the Queensland Nature Conservation Act 1992 was undertaken. At this time three species listed under the Nature Conservation (Wildlife) Regulation 2006 were observed, namely:

 Myrmecodia beccarii (ant plant, an epiphyte on other trees), EPBC Act and Nature Conservation Act 1992;

 Torrenticola queenslandica (an aquatic macrophyte), Nature Conservation Act 1992; and

 Pseuduvaria mulgraveana var. mulgraveana (a shrub/small tree, of the Annonaceae family, no common name), Nature Conservation Act 1992.

7.6.6 Myrmecodia beccarii (Ant Plant) Myrmecodia beccarii (ant plant) is a common epiphyte and is present (but not restricted to) the immediate Cairns area. It is commonly associated with intertidal areas where it is often found on mangroves or paperbark tea trees. It was not common in the lower Mulgrave River, and was only recorded as an isolated individual in an area of mangrove/paperbark swamp within Mutchero Inlet growing on an established mangrove (Avicennia marina). It is not considered that the ant plant will be significantly impacts by the proposed abstraction activities as the host trees are not groundwater dependant.

7.6.7 Torrenticola queenslandica Torrenticola queenslandica is an aquatic macrophyte commonly encountered on granite substrates in clear, fast flowing mountain streams between Gordonvale and Innisfail. The species is frequently exposed and as a result dies back during dry seasons when the flows of many of these streams are reduced. The water flows in the stream habitats in which this species is found are maintained by surface flows, not by groundwater interactions, as the granite substrate of the creek beds is invariably the base granite bedrock of the local area. Consequently, these streams have little to no interaction with any groundwater. Figtree Creek (upstream of the Bruce Highway), the area in which this species was identified in the study area, is an example of such system. The base substrate is granite, and the habitat area is outside of the area of alluvium that defines the Mulgrave River aquifer. Consequently, it is expected that abstraction from the Mulgrave River aquifer would not have any impacts on the abundance or distribution of this species in the study area.

7.6.8 Pseuduvaria mulgraveana Pseuduvaria mulgraveana var. mulgraveana is a small tree/shrub, and three individuals were identified in riparian rainforest in the middle to lower reaches of the Mulgrave River. This riparian rainforest community is considered to be seasonally dependent upon groundwater and during extended dry periods may rely on the aquifer to varying degrees. It is primarily only the larger rainforest trees (e.g. Castanospermum australe – black bean, and Dysoxylum gaudichaudianum – river mahogany) that have

42/15610/99537 Mulgrave River Aquifer Feasibility Study 117 Public Environment Report the necessary physical root structures to directly access the groundwater. Smaller species are invariably stressed, and it is not uncommon for there to be changes in the composition and abundance of rainforest species in riparian situations during extended dry periods. Such periods of stress favour the introduction of weed and pest species, such as pond apple, into riparian areas. P. mulgraveana is an example of one such smaller species that could be adversely impacted by prolonged dry conditions, however it is not dependent on aquifer resources and would not be adversely affected by changes in base river flows as a result of the abstraction in the order to 1 to 4%.

Table 23: Summary of Potential Impacts on Threatened Flora Species/Ecological Communities

Species/Community Potential impacts of borefield and Potential impacts of water extraction associated infrastructure construction

Listed Threatened Flora Species (EPBC Act)

Dendrobium mirbelianum No infrastructure will be located within any Not identified in study area. Mangrove orchid habitat areas.

Dendrobium nindii No infrastructure will be located within any Not identified in study area. habitat areas.

Eleocharis retroflexa No infrastructure will be located within any Not identified in study area. (sedge) habitat areas.

Huperzia phlegmarioides No infrastructure will be located within any Not identified in study area. Layered tassel-fern habitat areas.

Listed Threatened Flora Species, as listed under Queensland Nature Conservation Act 1992

Torrenticola queenslandica No infrastructure will be located within any Identified in Figtree Creek on granite bedrock Aquatic macrophyte habitat areas. upstream of Bruce Highway with no connection with the aquifer. Will not be impacted by abstraction from the aquifer.

Pseuduvaria mulgraveana No infrastructure will be located within any Identified as a component of riparian rainforest. var. mulgraveana habitat areas. Seasonally groundwater dependent.

Myrmecodia beccarii No infrastructure will be located within any Located as an epiphyte in mangrove forest in lower Ant plant habitat areas. Mulgrave River area. Will not be affected by abstraction from the aquifer.

Listed Threatened Communities (as listed under the Queensland Vegetation Management Act)

Endangered Regional No endangered regional ecosystems to No impacts from abstraction to 15 ML/day. Reduction Ecosystems be cleared for the borefield or any in surface flows approximately 1%, up to 4% once in associated reservoir, treatment or every 60 years. 7.3.3 pipelines. 7.3.6 7.3.10 7.3.12 7.3.28

Of Concern Regional No of concern regional ecosystems to be No impacts from abstraction to 15 ML/day. Reduction Ecosystems cleared for the borefield or any associated in surface flows approximately 1%, up to 4% once in reservoir, treatment or pipelines. every 60 years. 7.3.5 7.3.22

42/15610/99537 Mulgrave River Aquifer Feasibility Study 118 Public Environment Report 7.7 Fauna of Conservation Significance

7.7.1 Southern Casowary (Casuarius casuarius johnsonii) There are no records of the cassowary within the study area, and owing to the highly fragmented and intensely farmed rural landscape it is extremely unlikely that cassowaries could exist in such a landscape. Cassowaries are known from the adjacent World Heritage Area, however as this area will not be affected by abstraction from the Mulgrave River aquifer, no impacts are anticipated on any Cassowary habitat in the local region. Cassowaries may possibly utilise forest areas to the south of the study area adjacent to Mutchero Inlet. Vegetation in this area is outside the area of impact from the aquifer, and any impacts on surface water flows will not adversely impact on vegetation communities (and hence cassowary habitats) in this area.

7.7.2 Red Goshawk (Erythrorichis radiatus) This species is exceptionally unlikely to occur in the study area as habitat suitable for this species is not present. The species has never been observed in the general area. The changes in river flow are predicted in the order of magnitude of 1 to 4%, depending on climatic variability, and will not result in changes in vegetation community composition or type. Based on this, habitats for potential prey for this large raptor would remain unaffected, and if the species is present, it would not be adversely impacted by the operation of the borefield.

7.7.3 Australian Painted Snipe (Rostratula australis) This migratory species is dependent on shallow intertidal and freshwater wetlands, none of which exist in the Mulgrave River PER study area. The species was not observed in the study area, and based on habitat absence and no records of sightings, it is highly unlikely to occur in the area. Given these factors it is considered exceptionally unlikely that the operation of the borefield and changes in river flow in the order of magnitude of 1 to 4% will affect this species.

7.7.4 Waterfall Frog (Litoria nannotis) This frog species occurs in granite based, fast flowing streams, none of which are present in the study area. The predicted impacts on surface flows are for the alluvium based reaches of the Mulgrave River and Behana Creek that occur below 20 m in altitude. In these situations it is not possible for abstraction from this alluvium in any way to reduce river and creek flows at a higher altitude than the aquifer. The reaches of Behana Creek in which L. nannotis was recorded to have been observed occurs outside the study area (on base granite), and cannot be impacted by abstraction from the aquifer.

7.7.5 Common Mistfrog (Litoria rheocola) This frog is a species associated with fast flowing rainforest streams. It was not identified in any rainforest area that may be affected by the aquifer, and favourable habitat for this species was only identified in the adjacent WHA at altitudes above the aquifer. Therefore, the species will not be significantly impacted by groundwater abstraction and changes in surface flows. It is considered that changes in surface flows in the order of magnitude of 1 to 4% (during the dry season) will not adversely impact on rainforest streams in the study area, and if the frog is present in

42/15610/99537 Mulgrave River Aquifer Feasibility Study 119 Public Environment Report habitats outside of its preferential range then it still remains unlikely to be affected by abstraction impacts.

7.7.6 Other Fauna The River Health, River to Reef Research Project (December 2007) identified the Mulgrave River, and Behana Creek in particular, as having high ecological significance. The majority of the values identified were of significance at a state and regional level. The Commonwealth identified that six fauna and four flora species may be present within the aquifer area. Of these, only one species has been confirmed from existing records and field surveys to occur directly adjacent to the study area (Litoria nannotis, within the WTQWHA in Behana Creek gorge), and outside the area of influence of the aquifer. EPA (21/10/2008) have advised that Litoria rheocola has also been observed at Behana Creek, however the locations given are outside the aquifer extent and the creek in this location (exceeding 20 m AHD) will not be impacted by the proposal. Cassowaries may be present in the extreme lower end of the aquifer on the northern side of Mutchero Inlet (confluence of the Mulgrave and Russell Rivers), but is again outside the area of influence of the aquifer. Other protected fauna including the saltwater crocodile, spectacled flying fox and white-breasted sea eagle were identified within the study area during GHD field surveys. Of these, the spectacled flying fox was noted as consisting of a small camp of an estimated several hundred individuals within a mangrove/paperbark complex in Mutchero Inlet. These camps may be mobile, with flying foxes relocating according to resource availability. This macro bat is dependent on the resources of the WTQWHA, and the small area of riparian forest represented along the Mulgrave River constitute a very small part of the requirements of this species and the riparian vegetation would not be considered to be critical habitat for this species. The camp area of the flying foxes is in the tidal areas of Mutchero Inlet and is not affected by the aquifer. Consequently, abstraction from the aquifer is not predicted to have an impact on the camp vegetation mosaic. The white-breasted sea eagle would rely on some areas of the Mulgrave River area for feeding ecology and nesting purposes. It is likely that the species feeds on fish and other animals (such as freshwater turtles) that are present in this aquatic environment. Given the large territory this bird covers, the availability of other similar resources close by (Mutchero Inlet, Russell River), and the minimal impact of abstraction on environmental flows. It is considered that the proposed abstraction of water from the Mulgrave River aquifer would not adversely impact this species. Estuarine crocodiles are known to inhabit the Mulgrave River and three individuals (two being large animals over 3 m long) were identified. Crocodiles are territorial, so it is highly probable that the crocodiles were each located somewhere within its own defined territory. The two large individuals were identified in tidally affected areas in the lower Mulgrave River. In these reaches abstraction from the aquifer is not expected to make significant difference to river base flow (and tidal interactions), and it is considered that abstraction would not have an impact on these animals. The smaller crocodile observed in the upper Mulgrave River (due east of Aloomba) is within an entirely freshwater environment and would rely on the maintenance of deep pools of water and continual surface water base flow for provision of habitat including shelter and foraging opportunities. Changes in environmental flows that could affect the distribution of fish and water depths could force this animal further downstream (or upstream) and into the territory of another crocodile. This is an unlikely scenario, with limited changes in river flows as a result of the proposed abstraction.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 120 Public Environment Report Table 24: Summary of Potential Impacts on Fauna of Conservation Significance

Species/Community Potential impacts of Potential impacts of water extraction borefield and associated infrastructure construction

Listed threatened fauna species (EPBC Act)

Casuarius casuarius None anticipated The following regional ecosystems occur in the aquifer area, and johnsonii have been identified as Essential Cassowary Habitat (DERM Southern cassowary 2004): 7.3.3, 7.3.5, 7.3.6, 7.3.7, 7.3.10, 7.3.12, 7.3.17, 7.3.22, and (Australian) 7.11.7. No impacts on cassowary habitat predicted.

Erythrotriorchis radiatus None anticipated Species not present in the aquifer study area. Red goshawk

Rostratula australis None anticipated. Species not present in the aquifer study area. Australian painted snipe

Litoria nannotis * No infrastructure will be Will not be impacted by abstraction. Waterfall frog, torrent located within any habitat tree frog areas.

Litoria rheocola * No infrastructure will be Species not present in the aquifer study area. Common mistfrog located within any habitat areas.

Pteropus conspicillatus No native vegetation habitat to Abstraction will have no impact on the availability of habitat Spectacled flying-fox be cleared. roosting or foraging areas.

Haliaeetus leucogaster No habitat to be cleared Abstraction will have no impact on the availability of habitat White-breasted sea- roosting or foraging areas. eagle

Crocodylus porosus No habitat to be cleared. Abstraction will have no impact on the availability of breeding or Estuarine crocodile territorial areas.

7.7.7 Species contributing to World Heritage and National Heritage Values Currently available modelling suggests the area impacted by the proposed water extraction is likely to be restricted to the northern section of the aquifer. Presented below (Table 25) is a list of threatened / migratory fauna species possibly found within the study area. Potential impacts of infrastructure and water extraction to these species are also illustrated.

Table 25: Summary of Potential Impacts on Threatened Fauna Species

Value Potential impacts of infrastructure Potential impacts of water extraction development

Listed threatened fauna species (EPBC Act)

Casuarius casuarius johnsonii None anticipated The following regional ecosystems occur in Southern cassowary (Australian) the aquifer area, and have been identified as Essential Cassowary Habitat (NRME 2004): 7.3.3, 7.3.5, 7.3.6, 7.3.7, 7.3.10, 7.3.12, 7.3.17, 7.3.22, and 7.11.7. Habitats will not be adversely impacted by changes in predicted river base flows.

Erythrotriorchis radiatus None anticipated None anticipated. Species and habitat not Red goshawk present in study area.

Rostratula australis None anticipated. None anticipated. Species and habitat not Australian painted snipe present in study area.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 121 Public Environment Report Value Potential impacts of infrastructure Potential impacts of water extraction development

Litoria nannotis Typically a species of fast-flowing streams. Typically a species of fast-flowing streams. Waterfall frog, torrent tree frog None anticipated. None anticipated.

Litoria nyakalensis Found in fast flowing streams. May occur in None anticipated. Species and habitat not Mountain Mistfrog tributary streams of the Mulgrave. present in study area. None anticipated.

Litoria rheocola Associated with flowing streams. May occur None anticipated. Suitable habitat Common mistfrog in tributary streams of the Mulgrave. observed in the WTQWHA is outside the study area. None anticipated.

Nyctimystes dayi May occur in tributary streams of the None anticipated. Lace-eyed tree frog, Australian lacelid Mulgrave. Species and habitat not present in study None anticipated. area.

Taudactylus acutirostris Typically a species of fast-flowing streams. None anticipated. Sharp-snouted day frog, sharp- snouted torrent frog None anticipated. Species and habitat not present in study area.

Dasyurus hallucatus None anticipated. None anticipated. Northern quoll

Dasyurus maculatus gracilis None anticipated. None anticipated. Spotted-tailed quoll or yarri (North Queensland subspecies)

Hipposideros semoni No vegetation to be cleared. None anticipated. Semon's leaf-nosed bat, greater wart- nosed horseshoe-bat None anticipated.

Pteropus conspicillatus No vegetation to be cleared. Impacts of water extraction on suitable Spectacled flying-fox habitat (including Melaleucas and lowland None anticipated. rainforest habitats) will not be significant. None anticipated.

Rhinolophus philippinensis (large No vegetation to be cleared. None anticipated. form) Greater large-eared horseshoe bat None anticipated.

Saccolaimus saccolaimus No vegetation to be cleared. None anticipated. nudicluniatus Bare-rumped sheathtail bat None anticipated.

Table 26: Summary of Potential Impacts on Migratory Species or its Habitat

Value Potential impacts of infrastructure Potential impacts of water extraction development

Migratory Terrestrial Species – Birds

Haliaeetus leucogaster No vegetation to be cleared. None anticipated. White-bellied sea-eagle None anticipated.

Hirundapus caudacutus No vegetation to be cleared. None anticipated. White-throated needletail None anticipated.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 122 Public Environment Report Value Potential impacts of infrastructure Potential impacts of water extraction development

Hirundo rustica No vegetation to be cleared. None anticipated. Barn swallow None anticipated.

Monarcha melanopsis No vegetation to be cleared. None anticipated. Black-faced monarch None anticipated.

Monarcha trivirgatus No vegetation to be cleared. None anticipated. Spectacled monarch None anticipated.

Myiagra cyanoleuca No vegetation to be cleared. None anticipated. Satin flycatcher None anticipated.

Rhipidura rufifrons No vegetation to be cleared. None anticipated. Rufous fantail None anticipated.

Migratory Wetland Species – Birds

Gallinago hardwickii No habitat present. No habitat present. Latham's snipe, Japanese snipe None anticipated. None anticipated.

Nettapus coromandelianus albipennis No habitat present. No habitat present. Australian Cotton Pygmy-goose None anticipated. None anticipated.

Numenius minutus No habitat present. No habitat present. Little curlew, little whimbrel None anticipated. None anticipated.

Rostratula benghalensis s. lat. No habitat present. No habitat present. Painted snipe None anticipated. None anticipated.

Migratory Marine Species- Reptiles

Crocodylus porosus None anticipated. Changes in river base flows of between 1 to Estuarine crocodile, salt-water 4% are not anticipated to affect this species. crocodile

7.8 Invasive Fauna and Flora Species

7.8.1 Tilapia mariae Tilapia mariae is an aggressive fish that was introduced into Australia as an ornamental fish. Tilapia are farmed commercially in aquaculture activities overseas. Given the current widespread and existing problematic nature of this species, abstraction of up to 15 ML/day with minimal impacts on river flows is not expected to have an impact on the abundance or distribution of tilapia within the Mulgrave River or its tributaries. During the average dry season, river base flows are reduced by 1% and there is no predicted impact on tilapia distribution and abundance.

Tilapia are distributed in the Mulgrave River from the tidal areas in the Deeral township locality to areas upstream of the river outside of the aquifer area (to at least Peets Bridge). They also occur in Behana Creek, but do not prefer faster flowing or saline habitats. They are known to breed in all cane drains,

42/15610/99537 Mulgrave River Aquifer Feasibility Study 123 Public Environment Report minor waterways, as well as Behana Creek downstream of the Bruce Highway and the Mulgrave River itself. Decreases in river base flows (and environmental flow) may result in higher levels of salinity being encountered in these minor waterways and cane drains in the lower reaches of the Mulgrave River during extended dry periods (a 1 in 60 year event) under a maximum aquifer abstraction regime. Increases in salinity in these areas may induce tilapia to move further upstream into fresher reaches of the Mulgrave River (and Behana Creek) during such periods. Tilapia population abundance is not expected to increase as a result of abstraction under normal climatic conditions.

7.8.2 Annona glabra The major populations of pond apple are mapped in tidally affected poorly drained swamp and intertidal areas in the lower reaches of the Mulgrave River (refer to Figure 16). Potential habitat for pond apple exists for most of the length of the Mulgrave River, and during surveys for this project, individual plants were noted along most of the river length, primarily as individuals (not major populations). The major infestations were restricted to the southern (intertidal) section of the study area. The species were most common along overflow channels and tidally influenced areas. No dense infestations were noted in any complex riparian rainforest in the freshwater sections of the river. Abstraction from the aquifer at up to 15 ML/day is not predicted to have any impacts on river base and environmental flows for either normal dry seasons or extended dry seasons. As there are no changes in the salinity regime and environmental flows for the Mulgrave River there is no anticipated change in either the abundance or distribution patterns of pond apple. Pond apple fruits in the Mulgrave River (also present in Behana Creek) are primarily dispersed by current and tide movement. Pigs may contribute partially to pond apple distribution in areas associated with the lower reaches of the Mulgrave River. With tide movement as one of the key elements in controlling pond apple recruitment, changes in the tidal attenuation pattern as a result of reduced river flows may result in pond apple being distributed further upstream from the major population centres around the lower Deeral/Fishery Falls reaches of the river. An aspect to this scenario is that pond apple already exists along the entire length of the Mulgrave River in most drains, channels and tributaries as either isolated individual trees or small clumps areas with conditions favourable for their growth. If pond apple were to become dominant in these areas, it may be assumed that the species has had sufficient time to rapidly increase distribution and population since the 2004 mapping was undertaken, refer to Figure 16. Surveys undertaken in 2007 for this project identified only minor changes in the distribution and abundance in the population, and it appears that the current population of isolated individuals and small clumps may be in equilibrium. The existing tidal limit of the Mulgrave River (approximately due east of Aloomba) continues to provide opportunities for pond apple seeds to reach these middle reaches and colonise as dominantly as it has further downstream. Existing distribution may be limited by edaphic factors of soil type, drainage, slope aspect and other microhabitat specific conditions that would restrict pond apple recruitment. Overall, given the above aspects, there are no predicted impacts on the abundance and distribution of pond apple as a result of the abstraction.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 124 Public Environment Report 7.8.3 Hymenachne amplexicaulis and Urochloa mutica Hymenachne and para grass have differing potential to react to abstraction impacts on environmental flows being reduced in the Mulgrave River. Hymenachnes preference for clay soils is well documented, and the distribution of Hymenachne in the Mulgrave River area is entirely restricted to the lower Mulgrave in areas of heavy clay soils, often of an acid sulfate soil nature when exposed. These soils are not vulnerable to changes in the aquifer level as a result of abstraction, being beyond the modelled drawdown and areas of potential impact arising from aquifer abstraction. Hymenachne is a listed Weed of National Significance (WONS) and is the subject of ongoing monitoring and eradication in the Mulgrave River area. Current infestations are limited and are being monitored by landowners and Cairns Regional Council. Based on the information of predicted areas of drawdown and impact, it is highly unlikely that even under a scenario of maximum abstraction over prolonged dry periods would increase Hymenachne in the study area. Para grass (Urochloa mutica) is widespread and problematic in the study area. Along with guinea grass (Megathyrus maximus), it is the dominant grass of disturbed riparian areas of Mulgrave River, Behana Creek, Figtree Creek and other tributaries in the Mulgrave River. Unlike Hymenachne, para grass has a preference for alluvial sandy soils, and is an aggressive coloniser of any riverbank or bed with no established vegetation. Para grass has the ability to rapidly colonise even temporarily exposed riverbed sandy substrates, and it is a common feature of many of the wet tropics rivers that during the dry season most of the sandy riverbeds are colonised by this species. For proposed abstraction of up to 15 ML/day, this process will not be exacerbated by the abstraction proposed from the aquifer, with no quantifiable impacts on environmental flows predicted. There are numerous weed species in the Mulgrave River/Behana Creek area, with other common species including Arundo donax, Sphagneticala trilobata, Pennisetum spp, etc. Weed species, once established, are resilient to high flow events and thus may remain persistent in the landscape. Scouring and removal of weeds on newly accreted sediments may occur as result of extreme flows (flood scale) but in general would not be expected to ameliorate the full impacts of weed recruitment that may develop.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 125 Public Environment Report Figure 16: Mapped Extent of Pond Apple (WTMA 2004)

42/15610/99537 Mulgrave River Aquifer Feasibility Study 126 Public Environment Report 7.9 Climate Change The numerical groundwater model (Appendix D) identified that a large proportion of the annual water balance is shed as runoff. That is, the aquifer is saturated and has no capacity to absorb further recharge. This runoff exceeds the potential impact of abstraction from the aquifer under all scenarios and it was considered unnecessary to explicitly model the recharge and groundwater flow model impacts of climate change scenarios. Instead, a water balance impact approach has been utilised to show that the net excess recharge available in this catchment each year is larger than the potential impacts of climate change. This assessment is based upon information presented by the CSIRO report “Climate Change in Queensland under Enhanced Greenhouse Conditions” (Walsh et al. 2002). Detail of the assessment is provided in Appendix D. In summary, when very conservatively considering climate change in the worst case, there is predicted to remain an excess potential groundwater recharge in this catchment. If it were assumed that the increase in soil moisture deficit under climate change occurs wholly in the dry season, this would result in a slight delay in the initial groundwater recharge response than would otherwise have occurred. The recharge modelling undertaken in this study indicates that the soil moisture deficit is largely replenished within 30 days of the onset of the wet season. Although this is a simple water balance approach to the problem of climate change, it can be reasonably concluded that the worst-case predictions of climate change will result in minimal net losses to the aquifer water balance. This is due to the current net lack of aquifer storage with respect to the potential groundwater recharge in this catchment.

7.10 Risk Assessment Matrices The risk assessment matrices for environmental and social/cultural potential and likely impacts are presented in Table 27, Table 27 Table 28. It should be noted that the basis for this risk assessment is based on the accuracy and outputs of the Numerical Groundwater Model (Appendix D), supplemented with field surveys for matters of NES. There is a high degree of confidence in the risk assessment on matters of NES as defined in the Guidelines for the project. Matters of local, regional and state significance will be examined as part of any assessments required for approvals under Queensland state legislation.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 127 Public Environment Report Table 27: Environmental Risk Assessment Matrix

Consequence Likeli Risk Level Rating hood Element Description of Risk Basis of Risk Assessment Maximum Average High Average

Matters of National Essential habitat of the Southern cassowary No part of the aquifer study area is mapped as Essential Habitat for the southern Environmental may be impacted. cassowary, and cassowary sightings are extremely rare. The mosaic of complex Significance, as vegetation types at the mouth of the Mulgrave River provide essential resources to identified in the PER the cassowary, but will not be impacted by abstraction if water from the Mulgrave 0 0 1 0 0 guidelines. River aquifer, and the associated development of the borefield and associated infrastructure will have no quantifiable impacts on the southern cassowary or their habitat.

Environmental flows of the creeks comprising Frog species have only been recorded from fast flowing rocky streams on the edge the habitats of the Waterfall frog, Litoria and outside of the aquifer study area, e.g. Behana Creek. The flows of these 0 0 1 0 0 nannotis, may be reduced. creeks will not be impacted by changes in the potential flows of the Mulgrave River as a result of abstraction from the aquifer.

Common mistfrog, Litoria rheocola habitats The no records of the common mistfrog in the affected aquifer area. The species may be impacted by changes in flows of has only been recorded in adjacent World Heritage Areas at altitudes above 400 m. creeks within habitat areas. Environmental flows of streams through the habitat of this species will not be 0 0 1 0 0 affected by abstraction from the Mulgrave River aquifer.

Habitat of the red goshawk may be impacted. The red goshawk is not a bird species reliant on groundwater dependent ecosystems. It is a raptor of drier open forest and woodland, and there are no 0 0 1 0 0 records within 300 km of the study area.

Dendrobium orchid, Dendrobium There are no records of this species in the study area, and it was not identified mirbelianum, host trees may be affected. during field surveys for this species. It is an epiphytic species with a habitat preference for mangrove/wetland areas, and if it does occur in the Mulgrave River 0 0 1 0 0 catchment, is likely to be within tidal Mutchero Inlet and will not be impacted by abstraction from the aquifer.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 128 Public Environment Report Consequence Likeli Risk Level Rating hood Element Description of Risk Basis of Risk Assessment Maximum Average High Average

Blue antler orchid, Dendrobium nindii, host No records of this species within the study area and it was not identified during field trees may be affected. surveys. It is an epiphytic orchid with a preference for lowland palm and mangrove swamps, typically represented in the lower sections of the Mulgrave River. These are groundwater dependent ecosystems but in this area of the Mulgrave River these communities are maintained by surface flows from the Graham Range rather 2 1 1 2 1 than the aquifer. Given that the species is an epiphyte, it would not be directly impacted by environmental flow alterations, however there is a potential that the host species may be at risk.

Sedge, Eleocharis retroflexa, habitat areas This sedge is a component of groundwater dependent ecosystems found in the may be impacted by saline intrusion. Russell River area, primarily bulguru sedge swamp communities. There are no freshwater sedge swamps with suitable habitat for this species in the Mulgrave 1 0 1 1 0 River Aquifer Area, there have been no records of this species in the study area and was not identified during field surveys.

Listed Migratory Bird Species. No migratory bird species protected under JAMBA or CAMBA or otherwise listed have been recorded from within the aquifer area. The closest intertidal flats identified as suitable habitat for migratory wader birds is located at the mouth of Mutchero Inlet, facing the open ocean and will not be impacted by abstraction from the Mulgrave River aquifer. During the field surveys, a white breasted sea-eagle 0 0 1 0 0 was observed in the lowest section of the aquifer study area near Mutchero Inlet. This raptor is not reliant on groundwater dependent ecosystems in the aquifer area. Abstraction from the aquifer will have no impact on these species.

Other Listed Species Estuarine crocodile nesting habitat potentially The estuarine crocodile is ubiquitous in the Mulgrave River, with several observed (not identified under impacted. during the course of inspections and surveys for this project. Nesting areas for PER guidelines) female crocodiles are generally above the tidal limit, in dense vegetation usually in intertidal areas. There are records of crocodiles nesting in paperbark swamps at 0 0 1 0 0 the mouth of Mulgrave River. In these areas environmental flows will not be affected by abstraction from the Mulgrave River aquifer, and nesting habitats would not be affected. Prey resources would similarly not be affected by the abstraction.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 129 Public Environment Report Consequence Likeli Risk Level Rating hood Element Description of Risk Basis of Risk Assessment Maximum Average High Average

Habitat of the ant plant impacted by the The EPBC Act listed vulnerable ant plant (Myrmecodia beccarii) was identified in project. the lower reaches of the study area within Mutchero Inlet. The species is an epiphyte and not directly dependent on groundwater. In the area of habitat 0 0 1 0 0 preference (intertidal mangrove and near coastal areas) the habitat is not dependent on the Mulgrave River aquifer and this species is not at risk from abstraction from the aquifer.

Spectacled flying fox foraging and roosting The spectacled flying fox is widespread in the Wet Tropics, however species areas affected. abundance appears to be declining. This species typically has “camps” where many hundreds of bats may roost and breed. Many of the camps in the Wet Tropics are adjacent or within mangrove/estuarine areas. No flying fox camps were identified in this PER study, however individuals were noted feeding in 0 0 1 0 0 melaleucas at the southern end of the study area, and at various locations within remnant riparian vegetation. There is no evidence to suggest that abstraction from Mulgrave River aquifer will adversely impact river flows sufficiently to have any quantifiable impacts on the availability of roosting and foraging areas in the Mulgrave River Aquifer Area.

Impacts on World Alteration of freshwater flows into GBR Freshwater flows into estuaries and the GBR lagoon are important for maintenance Heritage Values lagoon. of a number of ecological processes, including breeding cycles of many near shore coastal and estuarine marine fish, crustacea molluscs, and invertebrates such as jelly fish (including the box jellyfish). As previously noted, Mutchero Inlet combines both the Mulgrave River and Russell River estuaries and carries extremely high flows during the wet season. The volumes of these flows will not impacted by the 1 0 1 1 0 abstraction of groundwater from the Mulgrave River aquifer. During dry season flow events, sufficient freshwater recharge from the Russell River and adjacent Graham Range (not included in the modelling scenarios) will mitigate and offset any minor loss in flows in the Mulgrave River.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 130 Public Environment Report Consequence Likeli Risk Level Rating hood Element Description of Risk Basis of Risk Assessment Maximum Average High Average

Alteration of environmental flows in the Only one portion of the mid/lower reach of the Mulgrave River has a common Mulgrave River affecting adjoining World boundary with the WTQWHA. The habitats in these areas are typical rainforested Heritage Areas. riparian systems, and are considered to be seasonally groundwater reliant. During average wet/dry season years of the abstraction level of up to 15 ML/day, less than 1% of the dry season flow of the river will be affected and there will be no impacts on the environmental flow of the river through the WHA. The establishment of monitoring gauges and adherence to a long term abstraction regime is necessary 1 1 2 2 2 to sustain environmental flows.

Endangered 7.2.1e: Simple Notophyll vine forest with Area of approx 1.9 ha at mouth of Mulgrave River, tidally influenced with surface Vegetation Types Syzygium angophoroides. Dune sands. water runoff from nearby Graham Range drainage lines. Community not (from Regional Important fruit source for birds, and very maintained by surface water runoff in this location, and not affected by Mulgrave 1 0 1 1 0 Ecosystem mapping significant for many migratory species. River aquifer of EPA)

7.2.1i: Mesophyll vine forest. Very wet and Small area on dunes amongst Melaleuca at mouth of Mulgrave/Russell Rivers. wet lowlands on dune sands. Community subject to tidal influence on margins. Community is beyond the extent 1 0 1 1 0 of the aquifer area, will not be impacted.

7.3.12a: Eucalyptus tereticornis, Corymbia Extremely small area on lower slopes of Graham Range north of Mulgrave River. tessellaris, E. pellita, C. intermedia, Not a swamp or wetland community, and is above the 20 m contour which typically Melaleuca dealbata and Lophostemon demarcates the ecological boundary of the aquifer area. Will not be affected by suaveolens woodland to open forest, often changes in either river environmental flow or lowering of groundwater. 0 0 1 0 0 with a secondary tree layer of Acacia mangium and A. crassicarpa. Alluvial plains of lowlands.

7.3.12b: Eucalyptus tereticornis, Corymbia On minor tributaries on northern side of Mulgrave River at base of Graham Range. tessellaris, E. pellita, C. intermedia, Not a swamp or wetland community. Dependent on groundwater in drought Melaleuca dealbata and Lophostemon situations. During normal years is not dependent on aquifer groundwater. suaveolens woodland to open forest, often with a secondary tree layer of Acacia At abstraction at up to 15 ML/day this community is not at risk even during 2 1 2 4 2 mangium and A. crassicarpa, and with a very prolonged dry periods well developed vine forest understorey. Alluvial plains of lowlands.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 131 Public Environment Report Consequence Likeli Risk Level Rating hood Element Description of Risk Basis of Risk Assessment Maximum Average High Average

7.3.23a: Simple-complex semi-deciduous Associated with better drained alluvium on riverine levees and is dominant notophyll to mesophyll vine forest. Moist and rainforest type on Mulgrave River, Behana Creek and major tributaries. This is a dry lowlands on alluvium, predominantly seasonally groundwater dependent ecosystem. Under the proposed abstraction of riverine levees. Associated with up to 15 ML/day this community is not at risk even during prolonged dry periods. watercourses, and provides important rainforest wildlife corridors and linkages within 2 1 2 4 3 a matrix of open forest and woodland communities or in cleared landscapes. The regional ecosystem has important water quality, fire break and erosion prevention benefits.

7.3.30: Complex of fernlands and sedgelands A very small and distinctive wetland community at base of Graham Range with emergent rainforest pioneering spp. maintained by seepage flows and surface water direct from Graham Range. Not Permanently wet peat swamps of alluvial aquifer groundwater dependent in this location. 0 0 1 0 0 plains.

7.3.40: Eucalyptus tereticornis (forest red Small remnants of open forest on well drained levees in mid Mulgrave River gum) open forest. Well-drained alluvial plains catchment. Not wetland or swamp communities, dependent on groundwater during 3 1 1 3 1 of lowlands. drought conditions.

Of Concern 7.1.4a: Mesophyll vine forest/mangrove Will not be affected by aquifer abstraction under normal flow years. Community Vegetation Types (as complex, of the brackish zone. Canopy also sustained by aquifer recharge and supply from the Russell River, and mapped by species include Heritiera littoralis, Bruguiera freshwater inputs from the Bellenden Ker Range. Queensland EPA) gymnorhiza, Sonneratia alba, Barringtonia 2 1 1 2 2 racemosa, Archontophoenix alexandrae, Elaeocarpus grandis, Melicope elleryana, Acacia mangium and Syzygium tierneyanum. Inland margins of mangroves and estuaries.

7.1.4b: Simple mesophyll vine forest with Unique communities at interface of freshwater and saline environments. The canopy dominated by Barringtonia racemosa proposed abstraction (15 ML/day) even during prolonged dry periods there will be and/or Hibiscus tiliaceus. Heritiera littoralis is no impact on the environmental flow. common on mangrove fringes. Semi- 2 1 2 4 2 permanently inundated brackish swamps.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 132 Public Environment Report Consequence Likeli Risk Level Rating hood Element Description of Risk Basis of Risk Assessment Maximum Average High Average

7.12.5b: Eucalyptus pellita, Corymbia The majority of this community is above the 20 m contour ecological boundary of intermedia and C. tessellaris open forest with the aquifer and are not groundwater dependent ecosystems. Abstraction from the Acacia celsa, A. cincinnata, A. mangium and Mulgrave River aquifer will not impact on this community. A. flavescens, with a very well developed vine 1 0 1 1 0 forest understorey. Very wet and wet lowlands and foothills.

7.2.8: Melaleuca leucadendra (weeping tea These are tall paperbark communities commonly associated with dune swale and tree) open forest to woodland. Sands of littoral environments. In the area of occurrence of this community there is no beach origin. groundwater interaction, being beyond the boundary of the aquifer (as modelled). 0 0 1 0 0 This community will not be impacted by abstraction from the aquifer.

7.3.10a: Mesophyll vine forest. Very wet and The majority of this community is above the 20 m contour ecological boundary of wet lowlands. the aquifer and are not groundwater dependent ecosystems. Abstraction from the 2 1 1 2 2 Mulgrave River aquifer will not impact on this community.

7.3.10c: Mesophyll vine forest with scattered A groundwater dependent system in the southern area of the aquifer. In this area feather palms (Archontophoenix alexandrae) the community receives substantial groundwater from the Malbon in the sub-canopy. Seasonally inundated Thomson/Graham Range and freshwater inputs from the southern section of lowland areas. Mulgrave River Aquifer Catchment, notably from Harvey Creek. Under the abstraction (15 ML//day) there will be no impacts on environmental flows in the 2 1 2 4 2 Mulgrave River that will affect this community.

Rare Flora Species Pseuduvaria mulgraveana, Torrenticola Four species of flora listed on the schedules of the Qld Nature Conservation queenslandica, Polyalthia patinata, (Wildlife) Regulation 2006 was observed in the field (includes Myrmecodia beccarii (Qld Listed) Myrmecodia beccarii. also listed under EPBC Act. Pseuduvaria mulgraveana and Polyalthia patninata were identified in riparian rainforest in the lower Mulgrave, in vegetation considered to be a groundwater dependent ecosystem (RE 7.3.23a). Torrenticola 2 1 1 2 1 queenslandica is an aquatic macrophyte found on granitic tributaries of the Mulgrave River outside the influence of the aquifer and not groundwater dependent. Myrmecodia beccarii is an epiphyte of the intertidal areas of the lower study area and not affected by the aquifer.

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Fisheries Reduced Flows affecting viability of Numerical modelling has identified that abstraction from the Mulgrave River aquifer recreational and commercial fishing stock. will have varying impacts on river flows depending on the degree of connectivity between the river and the aquifer, the abstraction regime, and seasonal climatic events. Based on the abstraction of up to 15 ML/day, less than 1% of the base flow of the river will be affected in an average year. This will have no impact on environmental flows or commercial fishing stock. 2 1 2 4 2

Introduced Species Potential to increase habitat availability for Tilapia are a declared noxious fish in the Mulgrave River and associated drains and Tilapia. tributaries and the Mulgrave River has a density of this species. It is a highly aggressive species that can live in most environments from daily tidal areas to freshwater impoundments. Abstraction from the aquifer under any regime and 0 0 1 0 0 subsequent potential impacts on environmental flows will not create habitat conditions more conducive to the spread of this fish species.

Potential to increase habitat availability for Pond apple is widespread and prolific plant species along the Mulgrave River and Pond Apple (Annona glabra). associated drains and tributary riparian areas. The species is extremely tolerant of wide array of environments from pure tidal to freshwater. Abstraction from the 1 0 1 1 0 aquifer under any regime and subsequent potential impacts on environmental flows will not create habitat conditions more conducive to the spread of this weed species.

Potential to increase habitat availability for Hymenachne is a ponded pasture grass which aggressively colonises freshwater Hymenachne. drains and chokes streams. Hymenachne is increasing in the Mulgrave River aquifer area, but does not tolerant saline conditions well. The species generally thrives in semi-water logged conditions, and is favoured by poor drainage 1 0 1 1 0 conditions. Abstraction from the aquifer has the potential to impact upon environmental flows during severe drought and prolonged dry season events. Under these conditions Hymenachne would be stressed and not readily able to recruit. The Risk Levels for the table can be interpreted as: 1-3.9 Low, 4 - 8.9 Medium, 9 -15.9 High, 16 - 25 Extreme.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 134 Public Environment Report Table 28: Social/Cultural Environmental Risk Assessment

Consequence Rating Risk Level Element Description of Risk Basis of Risk Assessment Likelihood Maximum Average High Average

Native Title Native Title interests or Native Title is deemed to have been extinguished in the areas determination may be held proposed to be used for the infrastructure associated with aquifer in areas proposed for project. Potential risk that future works, e.g. new reservoir, may be infrastructure. Delays in subject to Native Title. 1 0 1 1 0 project implementation to negotiate Native Title Issues.

Cultural Heritage Cultural heritage A search of the Cultural Heritage Register and Database did not items/values may be identify any registered cultural heritage. Potential crossing of the located in areas proposed Mulgrave River in riparian areas may disturb unrecorded Cultural 2 1 1 2 1 to be impacted by Heritage elements. infrastructure construction.

Groundwater dependent No wetlands are registered as of cultural heritage significance in the wetlands of cultural aquifer project area. The nearest wetlands of significance significance impacted by (Eubanangee Swamp and Woolanmaroo wetlands) are not within the 0 0 1 0 0 abstraction and lowering of Mulgrave River catchment and will not be impacted by the project. water table.

Landuse Loss of agricultural land. The borefield and associated delivery and treatment infrastructure are severance proposed to be located within road reserve and private property secured by CRCWW for the construction of the proposed infrastructure. It is not intended that any private land be acquired for the project, and implementation of the project will not alienate any 2 1 2 4 2 agricultural land. There may be some impediment to movement of agricultural machinery on road reserve utilised as cane headlands. In a number of instances cane growing has extended into the reserve. In sites where this occurs and bores are to be developed then some loss of farmed land will occur.

Loss of development The Mulgrave River Aquifer Area south of Gordonvale is a declared rights. Groundwater Management Area. The application of assessment policy means new developments proposed within the GMA will be subject to 3 2 5 15 10 referral and concurrence from DERM. Certain types of landuse development, e.g. intense urban development, are not compatible with the intent of GMA and will not be permitted within the aquifer GMA.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 135 Public Environment Report Consequence Rating Risk Level Element Description of Risk Basis of Risk Assessment Likelihood Maximum Average High Average

Impacts on existing bores. One existing bore will be impacted in the vicinity of the borefields by drawdown from the abstraction. Compensatory mechanisms to mitigate these impacts are relatively simple, and will require these 4 2 5 20 10 impacted bores to be redeveloped to greater depths to compensate for the drawdown impacts.

Visual Interruption of viewsheds. Pump houses are required for all bores. Pumps will be submersible types with electrical supply via overhead pole and line into a concrete pump shelter. Pipes will be buried and not visible. It is anticipated that the pump houses will be concrete and security fenced, with a total area 2 0 1 2 0 of approximately 10 m x 10 m required for each bore.

River Access Recreational use of the Based on the abstraction of up to 15 ML/day, less than 1% of the base river. flow of the river will be affected during extended dry seasons, and environmental flows not be impacted at any other time. The probability of abstraction affecting recreational use of the river based on this 1 0 1 1 0 scenario is extremely low.

The Risk Levels for the table can be interpreted as: 1- 3.9 Low, 4 - 8.9 Medium, 9 -15.9 High, 16 - 25 Extreme.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 136 Public Environment Report Table 29: Risk Assessment Matrix for Numerically Modelled Groundwater Potential Impacts

Consequence Rating Risk Level Element Description of Risk Basis of Risk Assessment Likelihood Maximum Average High Average

Groundwater Failure of sustained yield Extensive numerical modelling has indicated that abstraction to Supply during prolonged dry period. 15 ML/day is achievable without any quantifiable or measurable 4 1 3 12 3 impacts on groundwater even as modelled over the most conservative dry scenarios.

River Surface Impacts on Mulgrave River Numerical modelling has identified that abstraction from the Mulgrave Flows flows. River aquifer will have varying impacts on river flows depending on the degree of connectivity between the river and the aquifer, the abstraction regime, and seasonal climatic events. For the average dry 3 1 2 6 2 season maximum abstraction will result in a decrease in river base flows by 1%.

Changes in fluvial processes The majority of the morphological characteristics of the Mulgrave and river morphological River (sand bar movement, deposition and erosion events) are characteristics. defined during moderate to high flow events typically associated with the wet season. At these times of the year the river is a "gaining" 1 0 1 1 0 system, with recharge of surface flows from the aquifer. Flows are so very large that abstraction from the groundwater will have no impact (under any scenario) on the high and moderate event flows of the Mulgrave River that drive the fluvial processes of the river.

Alteration of freshwater flows Refer to Impacts on Mulgrave River Flows. Under normal seasonal into GBR lagoon. conditions the maximum abstraction will result in decreases of up to 1% of dry season flows. However, the input into the GBR lagoon is via Mutchero Inlet, a shared estuary with the Russell River. The Russell River is recharged by the flows from the extremely wet Bellenden-Ker/Bartle Frere catchments (rainfall to 10 m a year) with these flows mixing with the Mulgrave River. The overwhelming 1 0 1 1 0 majority of the freshwater inputs into the GBR lagoon are during the wet season, and abstraction from the Mulgrave River aquifer (under any scenario) will not impact in any measurable way on the volumes of freshwater entering the GBR. During dry seasons there is still sufficient freshwater input from Russell River and recharge from ranges east and west of the Mulgrave River aquifer to mitigate any loss of freshwater into Mutchero Inlet.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 137 Public Environment Report Consequence Rating Risk Level Element Description of Risk Basis of Risk Assessment Likelihood Maximum Average High Average

Changes in Salinity intrusion into The groundwater modelling has identified exposure and oxidation of salinity groundwater. potential acid sulfate soils will not result from abstraction of the maximum allowed allocation of 15 000 ML/year. During the average dry season there is no increase in the modelled level of salinity within 2 1 1 2 1 the aquifer area, however under extreme conditions for the maximum abstraction there may be a drawdown of up to 0.1 m at the saline interface with the aquifer in the south of the aquifer area. This will not impact on bores in the aquifer area.

Extension of saline interface The numerical groundwater modelling has not identified any potential upstream. for the penetration of the saltwater tidal wedge to advance any further upstream than the current interface. Abstraction from the aquifer will 0 0 1 0 0 not change the current status-quo in relation to the position of the interface.

Acid Sulfate Exposure of acid sulfate soils Potential acid sulfate soils have been mapped by DEEDI and DERM Soils as a result of modified surface for only a very small section of the immediate estuary and tidal area of flows. the lower Mulgrave River. This area will not be affected by changes in 0 0 1 0 0 surface flows (being completely tidal) wrought by abstraction from the aquifer.

Acid sulfate soils within Areas below 10 m AHD have been identified along the pipeline route infrastructure areas. and in the proposed infrastructure areas, notably in riparian areas associated with drains and the crossing of the Mulgrave River. There 3 1 2 6 2 is a potential for PASS to be encountered in these areas during construction.

Land Changes in surface levels may Land consolidation a consequence of abstraction from the aquifer will Consolidation affect cane farming area be minimal, in the worst case, the modelling predicts up to 0.26 m in drainage, roads and other built the immediate vicinity of abstraction points, and up to 0.09 m over the 3 1 2 6 2 infrastructure in vicinity of broader area. Any settlement will be gradual over several years and borefield drawdown influence is anticipated to be relatively uniform over the area and is not areas. expected to effect infrastructure or drainage. The Risk Levels for the table can be interpreted as: 1- 3.9 Low, 4 - 8.9 Medium, 9 -15.9 High, 16 - 25 Extreme.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 138 Public Environment Report 8. Prudent and Feasible Alternatives

8.1 Introduction The draft Far North Queensland Regional Water Supply Strategy (FNQWSS) was released for public comment in September 2007. The FNQWSS is part of the National Water Initiative (NWI) planning for Queensland. Water pricing and other issues related to implementation of the NWI are the responsibility of various Queensland government agencies under their specific legislation. Where these apply to the Mulgrave River Aquifer Project such issues will be dealt with directly between Cairns Regional Council and the Department of Environment and Resource Management. These issues are not within the Guidelines for the Public Environment Report. Once finalised, the FNQWSS will provide the framework, information and guidance for the management of water supply issues in the region over the next 50 years. The draft FNQWSS has predicted that Cairns City will have a shortfall in water supply in the vicinity of 30,000 ML/year by 2055. In order to meet the expected shortfall, the draft FNQWSS has recommended that the development of groundwater resources, in particular the Mulgrave River aquifer, represents a feasible alternative and/or supplement to the further development and instigation of surface water supply options. The Population Housing Fact Sheet of the Department of Infrastructure and Planning (August 2009) indicates the resident population of Cairns to be 147 538 with a projected population in 2021 of 195 540. The majority of the population is situated within Cairns City and towns such as Gordonvale It is anticipated that pressures on infrastructure, economy and environment will increase proportionately with population growth and as a result these will generate demand for energy, water supplies, telecommunications and transport corridors. These factors inevitably lead to a number of anthropogenic impacts such as the introduction of pest species and increased pollution emissions. A further 8700 hectares of the WTQWHA is likely to be cleared to make way for urban development in the next twenty years (McDonald, and Weston 2004). Goldsborough Valley acreage is an example of urban sprawl in the Mulgrave catchment. Current water for the immediate Cairns City area is drawn from Copperlode Dam and Behana Creek water supplies, all of which have major catchments wholly or predominantly within the WTQWHA. These water supplies are at risk of being taxed to the limit of its environmentally sustainable capability under the current population increase scenario. There have been a number of regional water planning studies and initiatives undertaken in North Queensland, the majority of which involve the construction of dams or weirs outside the WTQWHA, and are of limited scope in so far as addressing the immediate water demand needs for Cairns Regional Council. Consequently, Cairns Regional Council has undertaken a number of local studies into the potential water supplies for Cairns City. Options examined have included:

 increasing current abstraction from Behana Creek;

 increasing current abstraction from Copperlode Falls Dam;

 abstraction from a new facility at Lake Placid, on the Barron River; and

 abstraction from the Mulgrave River aquifer.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 139 Public Environment Report Of the above options, increasing abstraction from the existing Behana Creek and Copperlode Falls Dam sources has been deemed to be non-feasible. Behana Creek is at the maximum limit of sustainability of environmental flows and Copperlode Falls Dam has no capacity for increased abstraction. The evaluation of the scheme options that were considered indicated that the preferred option for the stage 1 augmentation is the Mulgrave River aquifer. It must be noted that over the medium term, both the Mulgrave River aquifer and Barron River water supplies will be required to augment existing water supplies to Cairns City. CRCWW has been granted approval by the former Environmental Protection Agency under Section 35 of the Queensland Nature Conservation Act 1992 to construct and operate an abstraction facility in the Barron Gorge National Park to withdraw up to 50 ML/day from Lake Placid (Barron River). This project has previously been referred to the Commonwealth under the provisions of the EPBC Act, and has not been considered to be a “controlled action”. The Lake Placid scheme has also been approved by the Wet Tropics Management Authority and is undertaken in accordance with an Indigenous Land Use Agreement between the Queensland Government and the traditional owners (Djabugay). CRCWW has approval to withdraw up to 50 ML/day from Lake Placid, subject to an application to release allocated water being granted by DERM. A comparative assessment between the Lake Placid and Mulgrave River Aquifer Scheme is presented in the following section. In future some form of abstraction will however be required from both schemes in order to meet the projected demand.

8.2 Comparative Impacts between Barron River (Lake Placid) Option and Mulgrave River Aquifer Scheme Recent water supply planning by Cairns Regional Council has identified that the Mulgrave River Aquifer Scheme and the Barron River scheme are necessary to meet the communities demand for water by around 2030. The options comparison does not present one scheme as more favourable than another, but highlights the varying impacts of each scheme to be considered in the design, planning and implementation of each.

8.2.1 Environmental An environmental risk assessment and environmental cost-benefit analysis was undertaken comparing the current approved Lake Placid (Barron River) scheme with the Mulgrave River Aquifer Scheme. Commonwealth and State government agencies have approved the construction of infrastructure within the Barron Gorge National Park (part of the WTQWHA) for an abstraction amount of 50 ML/day from Lake Placid. Water flows and water quality within Lake Placid are highly variable, and dependent on activities being undertaken in the Barron River catchment, much of which is on the Atherton Tablelands. The operational pattern of the Stanwell Hydro-electric Powerstation, upstream of Lake Placid, also results in a highly variable flow pattern in Lake Placid. Detailed planning and impact assessments for the Lake Placid scheme have not identified any potential impacts from the proposed abstraction of 50 ML/day that would have any quantifiable impacts on social, cultural and environmental attributes of the Barron Gorge National Park. Following a two-year monitoring program for the Wet Tropics Management Authority no matters of NES were identified that would be adversely impacted by the Lake Placid abstraction.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 140 Public Environment Report The abstraction of 15 ML/day would have no quantifiable environmental, social or cultural costs associated with the Mulgrave River aquifer scheme. This level of abstraction will not have any quantifiable impact on the environmental flows of the Mulgrave River and subsequently maintain groundwater dependent ecosystems and river morphological processes with no measurable penalty. This is on an environmental cost level commensurate with the proposed abstraction from the Barron River.

8.2.2 Social Issues related to social and cultural cost benefits are more likely to arise in the development of the Mulgrave River Aquifer Scheme than the Lake Placid scheme. These issues are primarily related to the landscape scale issues of planning and future development options, and the utilisation of the aquifer would essentially preclude further urban development about regional centres south of the Mulgrave River, particularly Aloomba, Charringa, Deeral and Fishery Falls under current planning policies. These issues are not applicable to the Lake Placid scheme. Social costs are evenly distributed between the Lake Placid and Mulgrave River Aquifer Scheme. Lake Placid requires restricting public access to parts of the Barron Gorge National Park, and will have ongoing visual impacts within the WTQWHA. The Mulgrave River aquifer scheme will have limited impacts on the operation of existing bores in the region (1 bore impacted) but will restrict further private allocations within the groundwater management area of the aquifer. There are no quantifiable cultural heritage costs with the implementation of the Mulgrave River aquifer scheme. No part of the known infrastructure area is subject to Native Title, nor are there any known cultural heritage values in the immediate vicinity or borefield, or infrastructure development areas. Known sites are restricted to the foothills, gorges and river systems within the adjoining WTQWHA outside the aquifer area and will not be impacted.

8.2.3 Infrastructure Costs Cairns Water and Waste (now known as CRCWW) have undertaken preliminary risk assessments of the construction and operational /maintenance phases of the Mulgrave River Aquifer Scheme for comparative purposes with the Lake Placid Option. Table 30 to Table 33 represent the scored risk assessment matrices as supplied by CRCWW. CRCWW utilised the methodology in this report to arrive at the calculated risk levels.

The Risk Levels for the tables can be interpreted as: 1- 3.9 Low, 4 - 8.9 Medium, 9 -15.9 High, 16 - 25 Extreme. The Primary Risk Levels (PRL – High Risk Level) were compared between the two proposed schemes to provide raw data for the preliminary cost/benefit analysis. A preliminary comparative construction and operational cost benefit between the two schemes is presented in Table 34 and in Table 35.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 141 Public Environment Report Table 30: CRCWW, Summary Construction Risk Assessment, Mulgrave River Aquifer

INFRASTRUCTURE (construction)

Consequence Rating Likelihood Risk Level Aspect Element Description of Risk Maximum Average High Average

Pipelines Centralised Raw Trunk Failure of the Pipeline 2 1 1 2 1

Creek crossing 1 0 3 3 0

Construction of pipeline 2 1 1 2 1

Retic Trunk Failure of the Pipeline 2 1 1 2 1

Construction of pipeline 3 2 1 3 2

Flooding 2 1 4 8 4

Bore collection system Failure of an element of the Trunk 3 2 1 3 2

Intake incl structure Structure Bore failure 2 1 1 2 1

Flooding 2 1 3 6 3

Land Tenure 2 1 1 2 1

Pump Pump failure 2 1 2 4 2

Pipe Pipe failure 2 1 1 2 1

Technology Not treatment for chemicals in proposed process 3 2 1 3 2

Power Supply Access to Power Cost 2 1 3 6 3

Flooding 2 1 1 2 1

42/15610/99537 Mulgrave River Aquifer Feasibility Study 142 Public Environment Report INFRASTRUCTURE (construction)

Consequence Rating Likelihood Risk Level Aspect Element Description of Risk Maximum Average High Average

Emergency Power Cost 2 1 1 2 1

Flooding 2 1 3 6 3

Table 31: CRCWW, Summary Operational Risk Assessment, Mulgrave River Aquifer

OPERATION

Consequence Rating Risk Level Aspect Element Description of Risk Likelihood Maximum Average High Average

Access to site Flooding Restricts access 2 1 3 6 3

Security of sites Fencing Cost 2 1 1 2 1

Maintenance 2 1 1 2 1

CCTV Cost 2 1 2 4 2

Monitoring Telemetry Signal strength 2 1 1 2 1

Power failure 2 1 1 2 1

Loss of control 2 1 1 2 1

Treatment Technology Lack of Operational experience 3 2 3 9 6

Cost 2 1 3 6 3

42/15610/99537 Mulgrave River Aquifer Feasibility Study 143 Public Environment Report OPERATION

Consequence Rating Risk Level Aspect Element Description of Risk Likelihood Maximum Average High Average

Maintenance Cost 2 1 3 6 3

Lack of resources 2 1 3 6 3

Operation regime Operating plant intermittent manner 3 2 4 12 8

Quality of Supply Turbitity Management of unpredicted events 3 2 2 6 4

Fe Mg Management of unpredicted events 3 2 2 6 4

pH Management of unpredicted events 3 2 2 6 4

contamination Management of unpredicted events 3 2 2 6 4

Quantity of Supply Peak Supply Not meeting demand 3 2 1 3 2

Average Supply Runs dry 4 3 1 4 3

Table 32: CRCWW, Summary Construction Risk Assessment, Lake Placid Scheme

INFRASTRUCTURE

Consequence Rating Risk Level Aspect Element Description of Risk Likelihood Maximum Average High Average

Pipelines Centralised Raw Trunk Failure of the Pipeline 3 2 3 9 6

Creek crossing 3 2 3 9 6

42/15610/99537 Mulgrave River Aquifer Feasibility Study 144 Public Environment Report INFRASTRUCTURE

Consequence Rating Risk Level Aspect Element Description of Risk Likelihood Maximum Average High Average

Construction of pipeline 3 2 3 9 6

Retic Trunk Failure of the Pipeline 3 2 3 9 6

Construction of pipeline 3 2 3 9 6

Flooding 3 2 4 12 8

Bore collection system Failure of an element of the Trunk 3 2 3 9 6

Reservoir Access Not getting access 3 2 2 6 4

Cost 3 2 2 6 4

Purchase of site Not getting Tender 3 2 2 6 4

Cost 3 2 2 6 4

Size Insufficient storage capacity 4 3 3 12 9

Intake incl structure Structure Bore failure 3 2 3 9 6

Flooding 3 2 4 12 8

Land Tenure 3 2 2 6 4

Pump Pump failure 4 3 3 12 9

Pipe Pipe failure 3 2 2 6 4

Treatment Plant Access Not getting access 4 3 2 8 6

42/15610/99537 Mulgrave River Aquifer Feasibility Study 145 Public Environment Report INFRASTRUCTURE

Consequence Rating Risk Level Aspect Element Description of Risk Likelihood Maximum Average High Average

Purchase of site Not getteing Tenure 4 3 2 8 6

Disposal Not getting EPA Approvals 4 3 2 8 6

Technology Not treatment for chemicals in proposed process 4 3 2 8 6

Power Supply Access to Power Cost 4 3 2 8 6

Flooding 4 3 4 16 12

Emergency Power Cost 3 2 2 6 4

Flooding 3 2 2 6 4

Table 33: CRCWW, Summary Operational Risk Assessment, Lake Placid Scheme

OPERATION

Consequence Rating Risk Level Aspect Element Description of Risk Likelihood Maximum Average High Average

Access to site Flooding Restricts access 3 2 4 12 8

Security of sites Fencing Cost 3 2 1 3 2

Maintenance 3 2 2 6 4

42/15610/99537 Mulgrave River Aquifer Feasibility Study 146 Public Environment Report OPERATION

Consequence Rating Risk Level Aspect Element Description of Risk Likelihood Maximum Average High Average

CCTV Cost 3 2 2 6 4

Monitoring Telemetry Signal strength 3 2 2 6 4

Power failure 3 2 3 9 6

Loss of control 3 2 3 9 6

Treatment Technology Lack of Operational experience 3 2 3 9 6

Cost 3 2 3 9 6

Maintenance Cost 3 2 3 9 6

Lack of resources 3 2 3 9 6

Operation regime Operating plant intermittent manner 3 2 4 12 8

Quality of Supply Turbitity Management of unpredicted events 3 2 4 12 8

Fe Mg Management of unpredicted events 3 2 4 12 8

pH Management of unpredicted events 3 2 4 12 8

contamination Management of unpredicted events 3 2 4 12 8

Quantity of Supply Peak Supply Not meeting demand 4 3 3 12 9

Average Supply Runs dry 4 3 2 8 6

42/15610/99537 Mulgrave River Aquifer Feasibility Study 147 Public Environment Report Table 34: Infrastructure Construction/Maintenance Cost/Benefit Comparison

Lake Placid Mulgrave River Difference (PRL) Weighted Rank Scores Scheme Aquifer Scheme

Aspect Element Risk Description Primary Risk Primary Risk Mulgrave Mulgrave Lake Placid Lake Placid Level Level River Aquifer River Aquifer

Pipelines Centralised Raw Trunk Failure of the Pipeline 9 2 7 0 2 0

Creek crossing 9 3 6 0 2 0

Construction of pipeline 9 2 7 0 2 0

Retic Trunk Failure of the Pipeline 9 2 7 0 2 0

Construction of pipeline 9 3 6 0 2 0

Flooding 12 8 4 0 1 0

Bore collection system Failure of an element of the Trunk 9 3 6 0 2 0

Reservoir Access Not getting access 6 NA 4 NA 1 NA

Cost 6 NA 0 NA 0 NA

Purchase of site Not getting Tender 6 4 2 NA 1 NA

Cost 6 6 0 NA 1 NA

Size Insufficient storage capacity 12 2 8 NA 2 NA

Intake incl Structure Bore failure 9 2 0 2 0 structure 7

Flooding 12 6 6 0 2 0

42/15610/99537 Mulgrave River Aquifer Feasibility Study 148 Public Environment Report Lake Placid Mulgrave River Difference (PRL) Weighted Rank Scores Scheme Aquifer Scheme

Aspect Element Risk Description Primary Risk Primary Risk Mulgrave Mulgrave Lake Placid Lake Placid Level Level River Aquifer River Aquifer

Land Tenure 6 2 4 0 1 0

Pump Pump failure 12 4 8 0 2 0

Pipe Pipe failure 6 2 4 0 1 0

Treatment Access Not getting access 8 NA NA 1 NA Plant 5

Purchase of site Not getting Tenure 8 NA 5 NA 1 NA

Disposal Not getting EPA Approvals 8 NA 5 NA 1 NA

Technology Not treatment for chemicals in proposed 8 NA NA 1 NA process 5

Power Supply Access to Power Cost 8 6 2 0 1 0

Flooding 16 2 14 0 3 0

Emergency Power Cost 6 2 4 0 1 0

Flooding 6 6 0 0 0 0

TOTAL 35 0 SCORES

42/15610/99537 Mulgrave River Aquifer Feasibility Study 149 Public Environment Report Table 35: Operational Cost/Benefit Comparison

Lake Placid Mulgrave River Difference (PRL) Weighted Rank Scores Scheme Aquifer Scheme

Mulgrave Aspect Element Risk Description Primary Risk Primary Risk Mulgrave Lake Placid Lake Placid River Level Level River Aquifer Aquifer

Access to site Flooding Restricts access 12 6 6 0 2 0

Security of Fencing Cost 3 2 1 0 1 0 sites

Maintenance 6 2 4 0 1 0

CCTV Cost 6 4 2 0 1 0

Monitoring Telemetry Signal strength 6 2 4 0 1 0

Power failure 9 2 7 0 2 0

Loss of control 9 2 7 0 2 0

Treatment Technology Lack of Operational experience 9 9 0 0 0 0

Cost 9 6 3 0 1 0

Maintenance Cost 9 6 3 0 1 0

Lack of resources 9 6 3 0 1 0

Operation regime Operating plant intermittent manner 12 12 0 0 0 0

Quality of Turbitity Management of 12 6 6 0 2 0 Supply unpredicted events

42/15610/99537 Mulgrave River Aquifer Feasibility Study 150 Public Environment Report Lake Placid Mulgrave River Difference (PRL) Weighted Rank Scores Scheme Aquifer Scheme

Mulgrave Aspect Element Risk Description Primary Risk Primary Risk Mulgrave Lake Placid Lake Placid River Level Level River Aquifer Aquifer

Fe Mg Management of unpredicted events 12 6 6 0 2 0

pH Management of unpredicted events 12 6 3 0 1 0

contamination Management of unpredicted events 12 6 3 0 1 0

Quantity of Peak Supply Not meeting demand 12 3 9 0 2 0 Supply

Average Supply Runs dry 8 4 4 0 1 0

TOTAL 22 0 SCORES

42/15610/99537 Mulgrave River Aquifer Feasibility Study 151 Public Environment Report Based on the criteria used by CRCWW in assessing the relative cost/benefits of the options, the Lake Placid Scheme scores highest on weighted rank scores for both infrastructure construction /maintenance and operational aspects. In terms of the cost/benefit comparison, development of the Mulgrave River Aquifer Scheme, based on the preliminary attributes identified above, currently represents a much higher return by comparison with the comparative construction, operation and maintenance risks inherent in the Lake Placid Scheme.

8.3 Environmental Cost Benefit Comparison An environmental risk assessment and environmental cost-benefit analysis was undertaken comparing the current approved Lake Placid (Barron River) scheme with the Mulgrave River Aquifer Scheme. Water flows and water quality within Lake Placid are highly variable, and dependent on activities being undertaken in the Barron River catchment, much of which is on the Atherton Tablelands. The operational pattern of the Stanwell Hydro-electric Power Station, upstream of Lake Placid, also results in a highly variable flow pattern in Lake Placid. Detailed planning and impacts assessments for the Lake Placid scheme have not identified any potential impacts from the proposed abstraction of 50 ML/day that would have any quantifiable impacts on social, cultural and environmental attributes of the Barron Gorge National Park. By comparison, there are caveats on the assumptions made in this report for potential environmental impacts arising from the Mulgrave River Aquifer Scheme. These caveats are based on a lack of accurate monitoring information to fully quantify groundwater/surface interactions relating to the Mulgrave River aquifer, and the subsequent potential impacts on river environmental flows. The Mulgrave River aquifer is not included in any Water Resources Operational Planning in the Wet Tropics, and detailed environmental flows for the Mulgrave River have not been determined. For an abstraction regime of 15 ML/day, it has been established earlier in the PER that there are no quantifiable environmental, social or cultural costs associated with the Mulgrave River aquifer scheme. This level of abstraction will satisfy the most conservative estimate for environmental flows of the Mulgrave River and subsequently maintain groundwater dependent ecosystems and river morphological processes with no measurable impact. This is on an environmental cost level commensurate with the proposed abstraction from the Barron River. The information above is summarised in the weighted scores for environmental cost/benefit assessment as shown in Table 36.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 152 Public Environment Report Table 36: Environmental Cost/Benefit Comparison between Lake Placid and Mulgrave River Aquifer Scheme

Lake Placid Mulgrave Difference ((PRL) Weighted Ranked Scheme River Scores Aquifer Aspect Element Description of Risk Scheme Mulgrave Mulgrave Primary Risk Primary Risk Lake Lake Placid River River Level Level Placid Aquifer Aquifer

Ecological

Impacts on listed endangered frog habitat Matters of NES 2 1 1 0 1 0 through reduced environmental flows

Impacts on habitat available for southern 1 1 0 0 0 0 cassowary

Impacts on migratory 1 1 0 0 0 0 species habitat

Habitat for listed flora to be 1 2 0 1 0 1 impacted

Vegetation Impacts on mapped 1 2 0 1 0 1 Communities Endangered REs

Impacts on mapped Of 4 2 2 0 2 0 Concern RE

Impacts on general 8 2 6 0 2 0 vegetation

Modification of freshwater World Heritage flows into the Great Barrier 2 1 1 0 1 0 Values Reef

Impacts on visual amenity 16 1 15 0 3 0 of infrastructure

Reduced environmental 2 1 1 0 1 0 flows affecting WTQWHA

General construction/maintenance 12 0 12 0 2 0 impacts on WHA values

Fisheries values (either as habitat, or for Fisheries values 1 1 0 0 0 0 recreational/commercial fishing) are degraded

Create or extend Introduced favourable conditions for 3 1 2 0 1 0 Species recruitment of problematic environmental weeds

Create or extend favourable conditions for 1 0 1 0 1 0 expansion of tilapia

42/15610/99537 Mulgrave River Aquifer Feasibility Study 153 Public Environment Report Lake Placid Mulgrave Difference ((PRL) Weighted Ranked Scheme River Scores Aquifer Aspect Element Description of Risk Scheme Mulgrave Mulgrave Primary Risk Primary Risk Lake Lake Placid River River Level Level Placid Aquifer Aquifer

Altered Exposure of acid sulfate environmental soils as a result of lowered 0 0 0 0 0 0 flows dry season flows

General groundwater dependent ecosystems 8 4 4 2 2 0 impacted by reduced extreme dry season flows

Changes in salinity regime in groundwater and 0 2 0 2 0 1 surface water

SUBTOTAL 14 3

Social/Cultural

Native Title issues may Native Title delay project 1 0 1 0 1 0 implementation

Cultural Heritage items may be identified during Cultural Heritage 3 2 1 0 1 construction and delay construction

Landuse Impacts on existing water 0 20 0 20 0 4 severance supplies

Loss of private developable land as a 1 15 0 14 3 result of the project proceeding

Recreational/ Restricted access to 1 1 0 0 0 0 aesthetic waterways

Modified viewsheds 16 1 15 0 3

SUBTOTAL 5 7

Hydrogeological

Surface flows Alteration of surface flows 1 6 0 5 0 1

Changes in fluvial 1 1 0 0 0 0 processes and dynamics

Saltwater/freshwater Salinity surface water interface 1 2 0 1 1 impacted

Salt water contaminates 0 0 0 0 0 0 water supply

42/15610/99537 Mulgrave River Aquifer Feasibility Study 154 Public Environment Report Lake Placid Mulgrave Difference ((PRL) Weighted Ranked Scheme River Scores Aquifer Aspect Element Description of Risk Scheme Mulgrave Mulgrave Primary Risk Primary Risk Lake Lake Placid River River Level Level Placid Aquifer Aquifer

Reducing freshwater 2 1 1 0 1 inputs into the GBRMPA

Exposure of acid sulfate Acid Sulfate Soils soils as a result of lowered 0 0 0 0 0 0 dry season flows.

Acid sulfate soils impact infrastructure construction 8 6 2 0 1 0 and maintenance

Land Land consolidation may 0 6 0 6 0 2 Consolidation affect local areas

SUBTOTAL 2 4 TOTAL SCORES 18 20

8.4 “Do Nothing Option” Abstraction from the Mulgrave River aquifer represents a feasible water supply source to supplement the Cairns Water Supply Scheme. Current water for the immediate Cairns City area is drawn from the Copperlode Falls Dam and Behana Creek water supplies, all of which have their major catchments wholly or predominantly within the WTQWHA. These existing surface water sources cannot be taxed any further without quantifiable impacts on environmental flows and resultant impacts on World Heritage values. Additional pressure will be placed on these existing water supply resources and on World Heritage values within the catchments if the Mulgrave River Aquifer Project does not proceed.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 155 Public Environment Report 9. Proposed Safeguards and Mitigation Measures

9.1 Environmental Management Plan

9.1.1 Structure and Responsibilities A draft Environmental Management Plan (EMP) based on the existing known preliminary planning information has been prepared to accompany the PER. The draft EMP is attached to this PER in Appendix C. The draft EMP outlines the framework for management, mitigation and monitoring of relevant impacts of the Cairns Mulgrave River Aquifer Project during planning, construction and operational phases. It should be noted that the draft EMP presented does not represent the final iteration of this document. The draft EMP will be refined and modified as Cairns Regional Council Water and Waste progress to a detailed Planning Study for the Mulgrave River Aquifer Scheme and details of infrastructure requirements, abstraction regimes, locations and construction methodologies become available. The Cairns Regional Council Water and Waste Operational and Maintenance EMP will identify conditions imposed by Queensland government regulatory and statutory authorities for the operation and maintenance aspects of the project. The final EMP will be required to address environmental flow monitoring in accordance with an approved Borefield Operation Plan. The Borefield Operation Plan will be included in the EMP and will identify monitoring requirements, trigger levels and corresponding threshold values for the operation of the borefield. A key action of the Borefield Operation Plan will be the establishment of Borefield operational rules to include trigger levels based on conditions such as stream flows or groundwater levels within the environmental flows framework. The trigger levels and associated threshold values will form the stimulus for management responses including abstraction rate reduction. The draft EMP provides guidance in addressing organisational structure, responsibilities, practices, procedures, processes and resources for implementing, achieving, reviewing and maintaining environmental management for and during planning, construction and operational phases of the project. Specifically the draft EMP addresses:

 Compliance with environmental legislation.

 Identification of environmental opportunities.

 Identification of environmental aspects, impacts and risks.

 Planning, evaluating and implementing appropriate on-site mitigation measures.

 Planning for emergency and contingency events that may arise from operations.

 Staff awareness of environmental issues.

 Monitoring and reporting of environmental performance. The structure of the draft EMP is outlined in Table 37.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 156 Public Environment Report Table 37: EMP Structure

Report Section Description of Section Contents

Introduction Provides background on the aquifer project and purpose of the EMP.

Statutory Obligations Identifies statutory requirements and permits, approvals or licences (if applicable) required for the project.

Responsibilities and Specifies the roles and responsibilities of those involved in implementing the Processes EMP, training requirements, monitoring and auditing requirements, and incident reporting procedures.

Aspects, Risks and This section identifies the aspects, risks and impacts of the Mulgrave River Impacts Aquifer Project. The aspect is the activity that causes an impact on the environment, which may be positive or negative and may occur onsite or offsite. To simplify, the aspect is the cause and the impact is the effect. By undertaking assessment of environmental aspects, risks and impacts the environmental values of the site can be identified. These values are presented in strategies for each of the three phases (planning, construction and operation).

Environmental This section specifies environmental management requirements for the Management environmental values identified within the following structure: Strategies Objective The guiding objective that applies to the value (what is hoped to be achieved through effective management of this element).

Performance The criteria by which the success of the implementation of Standard the policy will be determined.

Action The mechanisms and actions through which the objectives will be achieved.

Monitoring The process of measuring actual performance or how well the objective is being achieved.

Reporting The process of informing the appropriate person of monitoring outcomes. Format, timing and responsibility for reporting and auditing of monitoring results.

Corrective The action to be implemented and by whom, in the case Action where a performance requirement is not met.

9.1.2 Environmental Management Strategies The three phases of the project (planning, construction and operation) have been addressed individually with management strategies developed specifically for each phase. The strategies are based upon an aspect, risk and impact assessment, also completed individually for each phase. The environmental values listed in Table 38 have been addressed in the environmental management strategies.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 157 Public Environment Report Table 38: Environmental Values

Phase Values

Planning Residential Amenity Land Availability Soils Groundwater Cultural Heritage Matters of National Environmental Significance

Construction Soil Water Air Quality Waste Site Flora and Fauna Traffic Cultural Heritage

Operation Groundwater Soil Noise Traffic Matters of National Environmental Significance Stream Flow

9.2 Environmental Triggers and Thresholds for Actions

9.2.1 Borefield Operations Plan The Borefield Operations Plan is to be prepared based upon the results of the more detailed Phase 2 investigations to be undertaken in support of the project. A Borefield Operations Plan sets the triggers and thresholds for management actions in relation to the day-to-day management of the borefield. These triggers and thresholds in the Borefield Operation Plan will become the Operating Rules for the borefield; they become established as conditions of development and operation by Queensland regulatory authorities (in this case DERM). In order to establish the Operating Rules for the borefield a number of key parameters must be established in agreement with the Queensland regulatory authorities prior to the issue of development conditions on the project. These parameters include:

 The percentage drawdown (or actual groundwater level) at which point it is agreed begins to impact on groundwater availability to local users of the aquifer (i.e. register bore users) (threshold value).

 The percentage drawdown (or actual groundwater level) at which point it is agreed begins to impact on groundwater availability to ecological processes, including impacts on surface flows (threshold value).

42/15610/99537 Mulgrave River Aquifer Feasibility Study 158 Public Environment Report  The particular groundwater level point (in each monitoring bore) at which the impact on groundwater availability has an adverse affect on the operation of existing registered bores and prompts a management response (trigger level).

 The particular groundwater level point (in each monitoring bore) at which the impact on groundwater availability has an adverse affect on ecological resources and prompts a management response (trigger level).

 The total river flow (in ML/day calculated for each month) that must be retained for environmental flows for certain climatic conditions, such as the average recurrence interval (ARI). For example: during an average annual dry season; one below average rainfall year (1 in 15 year ARI dry season event); two successive below average dry seasons (1 in 30 year ARI event); and driest conditions on record (three successive below average dry seasons, or a 1 in 60 year ARI event).

 Based on the above, an agreement with the regulatory authorities as to what constitutes a “below average” rainfall year and clear definitions of the actual climatic events that stimulate a management response. In order to define the above trigger levels and threshold values, further detailed information will be needed on a number of key attributes and characteristics from the borefield as it is being developed. In particular, the groundwater levels in each of the bores need to be carefully monitored, and the results of pump tests and modelled drawdowns incorporated into the development of the threshold values and trigger levels for management actions. Additional information is also needed on flow data from Mulgrave River and Behana Creek in the area of potential impact (the drawdown zone of influence) from the borefield. Monitoring bores are to be established as part of the production borefield. The Department of Environment and Resource Management currently have a number of groundwater monitoring bores in the general area (up to 89); however the areas of specific interest are Behana Creek and the Mulgrave River. Depending on the location of the DERM monitoring network it may be necessary to install two additional monitoring bores immediately adjacent to the new Behana Creek and Mulgrave River gauging stations for the specific purpose of being the standard reference point for definition of threshold values and trigger levels adjacent to these sensitive environments. In relation to impacts on current bore users, existing monitoring bores in the area may be sufficient to provide the necessary groundwater levels to establish threshold values and trigger levels for actions. The use of stream flow data alone is insufficient to set threshold values and trigger levels for operation of the borefield. There are a number of uncontrollable, extrinsic factors affecting river flows other than the potential drawdown of the aquifer inducing “leakage” from the rivers back into the aquifer (thereby impacting on surface flows). In particular, there is up to a two week delay before abstraction from the aquifer induces this leakage from the rivers. In this period if there is recharge of the aquifer by local rainfall, or if there is rainfall in the upper catchments of Behana Creek and the Mulgrave River, both of these events will contribute to maintaining or increasing surface flows and the relationship between abstraction and river flows as a tool for establishing threshold values and trigger levels values becomes less precise. A coarse example of how threshold values and trigger levels may be shown in relation to the data and outcomes as modelled to date based on the observed and predicted drawdown of the test bores during the initial investigation. This is a coarse example as the bore testing was based on a hundred hour pump test for each of the two tested bores which aimed to stimulate the maximum possible response from the

42/15610/99537 Mulgrave River Aquifer Feasibility Study 159 Public Environment Report bore rather than simulate an abstraction commensurate with 15 ML/day (maximum). Notwithstanding, application of this data in the groundwater model identified that (on average) the drawdown in the borefield area (as opposed to individual bores) is approximately 3 m in the immediate depression cone about the bore, and up to 2 m drawdown of the aquifer over a wider area (up to 2 km from the abstraction point). This does not take into account the actual variance in depth of the individual bores, which must be calculated when the final bores are drilled, tested and groundwater levels established (which may vary from bore to bore depending on aquifer pressure and depth). Assuming that 2 m drawdown in a monitoring bore represents the maximum allowable abstraction (15 ML/day), then for a normal climatic year (and average river flows) with a predicted 1% impact on surface water availability in the dry season, this may be an acceptable sustainable abstraction level at which the borefield may be operated at. Should the drawdown in the bore exceed 2 m (potential threshold point), then it may be assumed that impacts on surface water flows will be greater than 1% and a bore level drawdown of 2.5 m may be a trigger level for management actions that involve modifying the borefield operation such as only using those bores away from the river areas, switching bores off, or in other ways reducing the total abstraction from the borefield. While predicted drawdowns have been used in the example above, the Operating Rules will use actual groundwater levels within the monitoring bores as the guideline for setting threshold and trigger levels. A number of trigger levels may be set in consultation with the regulatory authorities, however practically it would be envisaged that the following would be the most appropriate:

 Drawdown at abstraction of 15 ML/day for an average climatic dry season, with a 1% impact on surface water availability = threshold level (at whatever depths these correspond to within the monitoring bores), borefield operates to maximum capacity.

 Drawdown at abstraction of 15 ML/day for one dry season below average rainfall event = trigger level 1, borefield operation may involve selective use of bores to move impact from sensitive areas.

 Drawdown at abstraction of 15 ML/day for two consecutive dry seasons of below average rainfall events = trigger level 2, borefield total capacity reduced.

 Drawdown at abstraction of 15 ML/day for three consecutive dry seasons of below average rainfall (1 in 60 year) events = trigger level 3, borefield does not operate or at very reduced capacity. The actual bore levels will be specific to each bore and derived only after further investigations have been completed. The response of individual monitoring bores to different abstraction regimes will be modelled when the additional flow data from the newly installed gauging stations on Behana Creek and Mulgrave River become available, and subsequently a more detailed groundwater model can be derived that better defines the relationship between abstraction, groundwater levels (in individual bores) and effects on river flows.

9.2.2 Environmental Flow Monitoring The operation of the borefield and abstraction from the Mulgrave River aquifer will be subject to ongoing monitoring of both groundwater levels (via the existing bore monitoring network, any additional monitoring bores as required and the production bores when established) and stream flows in the Mulgrave River and Behana Creek. In order to fully establish the relationship between groundwater levels and impacts on river flows it will be necessary to have additional gauging stations on the Mulgrave

42/15610/99537 Mulgrave River Aquifer Feasibility Study 160 Public Environment Report River and on Behana Creek to ensure that environmental flows are not being impacted by the abstraction from the aquifer. Monitoring of groundwater levels, river flows and heights, and subsequent compliance with the Borefield Operating Rules will be the responsibility of Cairns Regional Council Water and Waste. Cairns Regional Council Water and Waste will be responsible for the construction of additional gauging stations and acquiring and managing the data. A final determination of environmental flow requirements will be undertaken when further data on flows is available from the existing and new gauging stations as well as from consultation with research organisations and government agencies with specific management authority and technical authority in this area.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 161 Public Environment Report 10. Conclusions and Recommendations

10.1 Summary of Impacts The modelling undertaken for the project indicates that on average, base river flows will be reduced by 1% during the normal dry season low flow event, and up to 4% during an extended dry period (a 1 in 60 year event). These figures are based on a model incorporating groundwater abstractions above the actual operating regime for the borefield the demand requirements of the aquifer, as this was not known at the time of deriving the model. The model adopted an abstraction of 15 ML/day on every day of the year. The reality of operating the borefield as a supplementary source to meet demand indicates that it would probably not be used during the wet months of the year (January, February, March) and may only be used up to its maximum daily abstraction capacity on an intermittent basis during the dry season depending on demand requirements. Therefore, it is considered that the modelled impacts are conservative and the actual impacts on the base river flows (as a result of drawdown from the aquifer) are likely to be substantially less than the 1% to 4% reduction predicted. The modelling will be refined during the next phase of more detailed assessments and investigations. It is also noted that abstraction from the aquifer does not instigate an immediate response in surface flows. At a constant sustained abstraction rate of 15 ML/day, there may be a lag of two weeks or more before a response in flows in both Behana Creek and Mulgrave River are observed. If there is rainfall in the upper catchment of either system during the lag period river flow levels may increase and the total impact of the drawdown on river flows would not be quantifiable (given that the estimated average impact on river flows is estimated to be only 1% in a normal dry season year). It is proposed as part of the safeguarding and mitigation measures that operation of the borefield will be in accordance with an Environmental Management Plan that will include a Borefield Operation Plan. The Borefield Operation Plan will identify thresholds and triggers for instigating management actions. The Environmental Management Plan and Borefield Operation Plan will be an outcome of the Phase 2 investigations, which are planned for completion by October 2010.

10.2 Justification for Proposed Action Abstraction from the Mulgrave River aquifer represents a feasible water supply source to supplement the Cairns Water Supply Scheme. Water for the immediate Cairns City area is presently drawn from Copperlode Falls Dam and Behana Creek, both of which have their major catchments wholly or predominantly within the WTQWHA. These sources are presently at or near the adopted safe yield for existing demands for water by the community (Cairns Regional Council, 2006). The safe yield adopted considers the environmentally sustainable capability of each source within the WTQWHA. Should the Mulgrave River Aquifer Project (the “Action”) not proceed then the Barron Scheme will have to be implemented at a higher environmental, social and economic cost. The existing approved additional water supply scheme (Lake Placid) will not by itself meet the projected demand for the growing Cairns population, and existing surface water sources are within the WTQWHA and cannot be taxed any further without quantifiable impacts on environmental flows and resultant impacts on World Heritage values.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 162 Public Environment Report Development of the borefield and abstraction from the ground in the context of an extremely modified rural landscape is a preferable option to the increasing abstraction from existing surface water supplies or developing new water supplies, within the Wet Tropics of Queensland World Heritage Area.

10.3 Compliance with Principles of Ecologically Sustainable Development Development of the Mulgrave River aquifer as a supplementary water supply to Cairns City is in compliance with the Principles of Ecologically Sustainable Development (ESD) as outlined in Section 3 A of the EPBC Act. The decision to investigate the Mulgrave River aquifer as a water supply source was made by CRCWW after consideration of the short and long term economic, environment, social and equitable costs of a number of potential options. A number of the other options have not been progressed due to their potentially high economic, environmental and social costs. A new source from the Barron River at Lake Placid has progressed to a detailed planning level and received approval from government. However, the Barron River intake is considered to present a higher economic, environmental and social cost that the Mulgrave River Aquifer Scheme and the Barron River intake will ultimately be required to meet the community demand for water. The degree of certainty in the level of impacts relating to an abstraction rate of 15 ML/day from the Mulgrave River aquifer is very high. The extensive technical studies commissioned by CRCWW into the feasibility of the aquifer as a supplementary water supply source have demonstrated scientific rigour in determining that the likely levels of impacts are minimal and that the project can be managed with measures implemented to prevent environmental degradation. The implementation of the Mulgrave River Aquifer Scheme is a preferable option to the further degradation of World Heritage values through increased abstraction of surface water from rivers within the WTQWHA. Use of the aquifer resource minimises pressures on the WTQWHA and the adoption of an abstraction regime, which has no to minimal quantifiable impacts on the base river flow of the Mulgrave River and Behana Creek, ensures that the health, diversity and productivity of the environment values of the Mulgrave River and Behana Creek are maintained for future generations. Biological diversity and ecological integrity within the Mulgrave River Aquifer Area has been impacted through historical and current landuse, with over 90% of the study area having been cleared of vegetation (the majority under sugar cane). The process followed by CRCWW to acquire the existing groundwater licence allocation and, more importantly, the implementation of management actions and mitigation measures proposed as part of the additional authorisations will ensure those remnant biological values in the study area, and the integrity of the existing environment, will not be further compromised by the project.

10.4 Matters of National Environmental Significance This PER has identified that no unavoidable impacts on matters of NES will occur as a result of the proposed works. Detailed technical studies have demonstrated that implementation of the project (abstraction up to 15 ML/day) will result in changes in the river baseflows of between 1 to 4%. It is not expected that such changes in flow rate will have a significant impact on matters of NES.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 163 Public Environment Report 10.5 Environmental Acceptability Abstraction from a groundwater resource that does not adversely impact environmental values is more environmentally acceptable than increasing abstraction from existing surface water sources in World Heritage Areas (Behana Creek and Copperlode Falls Dam), construction of further dams, and/or raising the dam wall height on existing structures. Primary environmental costs are social, with immediate impacts being one private registered bore in the immediate area of the borefield adversely impacted by abstraction from the borefield. Deepening this bore may ameliorate impacts on this private bore.

10.6 Technical Feasibility The Mulgrave River Aquifer Project uses technology and methodologies that are proven and have been implemented for other urban water supply projects in Australia. The proposed abstraction allocation is deemed to be both environmentally and technically feasible, with detailed technical studies outlining the likely risks for both attributes.

10.7 Compliance with the Objectives of the Environment Protection and Biodiversity Conservation Act 1999 The overriding Objectives of the EPBC Act and the manner in which this project meets these Objectives are summarised below: “To provide for the protection of the environment, especially Matters of National Environmental Significance”

This PER, and the supporting studies undertaken for this PER, have concluded that abstraction from the Mulgrave River aquifer will not have any quantifiable effects on the Matters of NES identified in the PER. In this respect the project complies with the overall requirement in providing protection to the environment, and particularly to Matters of NES. “Conserve Australian biodiversity” No native vegetation or fauna habitats are to be cleared or disturbed for the construction and operation of the project. No habitats of any protected terrestrial species will be impacted by the proposal. “Provide a streamlined national environmental assessment and approvals process.” This PER is in itself is a part of the environmental assessment and approvals process and has been produced in accordance with the guidelines for the project issued by the Commonwealth. In this regard, this project and that approval process is compatible with the objectives of the EPBC Act. “Enhance the protection and management of important natural and cultural places.”

Abstraction from the Mulgrave River aquifer, in an area dominated by sugar cane landuse, is a more sustainable approach to the protection and management of important natural and cultural places than other potential water source options in the region. The other immediate options for water supplies considered include increasing abstraction from existing sources in the WHA (e.g. Behana Creek), which will have adverse impacts on environmental flows. Use of the aquifer resource will not adversely impact upon the World Heritage values of the Wet Tropics Area, nor any cultural heritage areas. In this aspect this project does achieve this objective.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 164 Public Environment Report “Control the international movement of wildlife, wildlife specimens, and products made or derived from wildlife.” This objective of the EPBC Act is not applicable to this project. “Promote ecologically sustainable development through the conservation and ecologically sustainable use of natural resources.” The proposal to abstract water from the Mulgrave River aquifer represents a more ecologically sustainable approach to conservation and use of natural resources than other water supply options including further abstraction from existing surface waters within the World Heritage Area, and/or the creation of further dams in the Wet Tropics. Desalination options are not environmentally sustainable within the Great Barrier Reef Marine Park Area and require a currently unachievable level of technology and capital cost to implement.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 165 Public Environment Report 11. References

ABRS (Australian Biological Resources Study Australian Faunal Directory) (2009). Electronic document http://www.environment.gov.au/biodiversity/abrs/online-resources/fauna/afd/taxa (Accessed 21/08/09).

Allen G., Midgley S. and Allen M. (2002). Field Guide to the Freshwater Fishes of Australia. Western Australian Museum. ASFB (Australian Society for Fish Biology) (2003). Conservation Status of Australian Fishes –2003. Australian Society for Fish Biology Newsletter 33; 60-65. Cairns Regional Council and GHD (2007). Mulgrave River Aquifer Project – Aquifer Abstraction Feasibility Study. Cairns Regional Council and GHD (2009). Report for Overall Water Supply Strategy for Cairns – Planning Report. Commonwealth Department of the Environment and Heritage (2003). Weed Management Guide. Hymenachne or Olive Hymenachne (Hymenachne amplexicaulis). Electronic document http://www.weeds.gov.au/publications/guidelines/wons/pubs/h-amplexicaulis.pdf (Accessed 17/08/09). DPI&F (Department of Primary Industries and Fisheries) (2003). Fish Note. Mangrove jack (sea perch) Lutjanus argentimaculatus. Electronic document http://www2.dpi.qld.gov.au/fishweb/2194.html (Accessed 13/08/09). DPI&F (Department of Primary Industries and Fisheries) (2007). Fact Sheet. Pond apple Annona glabra. Electronic document http://www.dpi.qld.gov.au/documents/Biosecurity_EnvironmentalPests/IPA-Pond- Apple-PP58.pdf (Accessed 11/08/09). DEEDI (Department of Employment, Economic Development and Innovation Queensland Primary Industries and Fisheries (2009). Exotic Pest Fish. Electronic document http://www.dpi.qld.gov.au/cps/rde/dpi/hs.xsl/28_144_ENA_HTML.htm (Accessed 18/08/09). DPI&F (Department of Primary Industries and Fisheries) (2007). Fact Sheet. Para grass Brachiaria mutica. Electronic document http://www.dpi.qld.gov.au/documents/Biosecurity_EnvironmentalPests/IPA- Para-Grass-PP90.pdf (Accessed 17/08/09). Froese, R. and D. Pauly. Editors. 2009. FishBase. World Wide Web electronic publication. www.fishbase.org, version (07/2009). JCU (James Cook University) (2006). Pest fish profiles. Tilapia mariae – Spotted Tilapia. Electronic document http://www.actfr.jcu.edu.au/Projects/Pestfish/PDFs/Tilapia%20mariae.pdf (Accessed 11/08/09). Jones, A., Rudstam, L. and Rayner, T. (2007). Natural Diet of an Australian Freshwater Pipefish. Nature Precedings. Electronic document http://dx.doi.org/10.1038/npre.2007.329.1. (Accessed 17/08/09).

Kroon F.J. and Johnson J.W. (2006). Range extension for the Mulgrave River Goby (Glossobius sp.)(Pisces:Gobiidae) in Northern Queensland. Memoirs of the Queensland Museum Volume 52 Part 1.

42/15610/99537 Mulgrave River Aquifer Feasibility Study 166 Public Environment Report Pusey B., Arthington A.and Read M. (1995). Species richness and spatial variation in fish assemblage structure in two rivers of the Wet Tropics of northern Queensland, Australia. Environmental Biology of Fishes 42, 2, 181-199. Pusey B., Kennard M. and Arthington A. (2004). Freshwater Fishes of North-Eastern Australia, CSIRO Publishing. Pusey B., Kennard M. and Arthington A. (2007). Freshwater Fish as Indicators of Ecosystem Health in Wet Tropics Streams. In Arthington, A. and Pearson R. (eds) Biological Indicators of Ecosystem Health in Wet tropics Streams. Final Report Task 3 Catchment to Reef Research Program Cooperative Research Centre for the Great Barrier Reef World Heritage Area pp176-230. Rayner, T. S. (2007). The trophic ecology of the freshwater fishes of an Australian rainforest River. James Cook University. Russell, D., Hales P. and Helmke S. (2004). Stream Habitat and Fish Resources in the Russell and Mulgrave Rivers Catchment. Department of Primary Industries, Northern Fisheries Centre, Cairns Information Series QI96008. Small, A. (1999). FNQ2010 Biodiversity Remnant Vegetation Mapping, Department of Local Government and Planning. Stanton, J.P and Stanton, D., (2004). Wet Tropics Vegetation Mapping Project, Wet Tropics Management Authority, Cairns, Qld. Wager R. and Jackson P. (1993). The Action Plan for Australian Freshwater Fishes. Electronic document http://www.environment.gov.au/biodiversity/threatened/publications/action/fish/6.html (Accessed 17/08/09).

42/15610/99537 Mulgrave River Aquifer Feasibility Study 167 Public Environment Report Appendix A Guidelines for the Content of a Draft Public Environment Report

Mulgrave River Aquifer, Borefield and associated infrastructure, Cairns, Queensland

42/15610/99537 Mulgrave River Aquifer Feasibility Study Public Environment Report Appendix B Cairns Regional Council General Policy 1:04:43

Protection of the Natural Environment

42/15610/99537 Mulgrave River Aquifer Feasibility Study Public Environment Report Appendix C Draft Environmental Management Plan

Borefield and infrastructure construction and operation

42/15610/99537 Mulgrave River Aquifer Feasibility Study Public Environment Report Appendix D Numerical Groundwater Modelling Technical Report

Technical Supporting Information to PER

42/15610/99537 Mulgrave River Aquifer Feasibility Study Public Environment Report Appendix E Hydrogeology Report

Technical Supporting Information to PER

42/15610/99537 Mulgrave River Aquifer Feasibility Study Public Environment Report Appendix F Flora and Fauna Survey Report

Technical Supporting Information to PER

42/15610/99537 Mulgrave River Aquifer Feasibility Study Public Environment Report Appendix G Responses to Draft PER

Summary of Responses

42/15610/99537 Mulgrave River Aquifer Feasibility Study Public Environment Report Appendix H General PER Information

42/15610/99537 Mulgrave River Aquifer Feasibility Study Public Environment Report