PLANS AND DOCUMENTS referred to in the PDA DEVELOPMENT APPROVAL Approval no: DEV2017/844 Date: 25 October 2017 Flinders Precinct 1: Concept Lake Management Plan April 2017 Document Control Sheet Document: R.B21415.001.04.FlindersLakeConceptM BMT WBM Pty Ltd anagementPlan.docx Level 8, 200 Creek Street Brisbane Qld 4000 Title: Flinders Precinct 1: Concept Lake Australia Management Plan PO Box 203, Spring Hill 4004 Project Manager: Lucy Peljo Tel: +61 7 3831 6744 Fax: + 61 7 3832 3627 Author: Paul Dubowski, Lucy Peljo, Brad Dalrymple ABN 54 010 830 421 Client: Pacific International Development www.bmtwbm.com.au Corporation Client Contact: Ian McLean Client Reference: Synopsis: Concept management plan for the proposed lake within Precinct 1 of the Flinders Master Planned Community. This plan has been prepared in response to the Terms of Reference from Economic Development Queensland (EDQ) and to augment the successful planning, design, implementation and management of the proposed lake. REVISION/CHECKING HISTORY Revision Number Date Checked by Issued by 0 7 September Brad Lucy 2015 Dalrymple Peljo 1 6 May 2016 Brad Lucy Dalrymple Peljo 2 15 June 2016 Martin Giles Lucy Peljo 3 12 April 2017 Martin Giles Lucy Peljo 4 24 April 2017 Martin Giles Lucy Peljo DISTRIBUTION Destination Revision 0 1 2 3 4 5 6 7 8 9 10 Pacific International Group PDF PDF PDF PDF PDF BMT WBM File PDF PDF PDF PDF PDF BMT WBM Library PDF PDF PDF PDF PDF G:\Admin\B21415.g.nc_Flinders Project\R.B21415.001.04.FlindersLakeConceptManagementPlan.docx Flinders Precinct 1: Concept Lake Management Plan i Executive Summary Executive Summary The Flinders Master Planned Community is a 4,000 hectare landholding proposed for development by the Pacific International Group. The site is located in Undullah, south west of Logan City and includes a 1,000 hectare area known as Precinct 1, which is to feature a lake. The primary functions of the lake are amenity and secondary contact recreation including uses such as canoeing, boating and fishing. It is anticipated that the lake will be predominantly open water with mostly fringing vegetation and some ‘hard edge’ treatments, including (for example) boardwalks and rock walls. Boat ramps, jetties, pontoons, canoe launching facilities and other community facilities are also likely to maximise recreation opportunities. The objectives of this report are to: x Augment the design and operation of the lake x Respond to items within the Terms of Reference (TOR) given by Economic Development Queensland (EDQ) in relation to the proposed lake. This primarily includes: ż Identification of key risks associated with design, construction, establishment and operation of the lake ż Identification of performance criteria which are to be included in approval conditions aimed at minimising the identified risks ż Conceptual design verification for matters specifically requested by the TOR ż Developing a Concept Lake Management Plan which includes: – Concept Water Quality and Sediment Monitoring Program – Concept Lake Maintenance Plan. A summary of responses to the TOR items related to the lake is provided in Table 1. G:\Admin\B21415.g.nc_Flinders Project\R.B21415.001.04.FlindersLakeConceptManagementPlan.docx Flinders Precinct 1: Concept Lake Management Plan ii Executive Summary Table 1 Summary of Responses to TOR Lake-Related Items Has TOR Report TOR Item item been Comments Section addressed? Flooding Yes 4.14 x The management of flooding is being addressed concurrently to this report in the ‘Flinders Precinct 1: Flood Impact Assessment’ (BMT WBM, 2017). Lake Water Yes x The key objective of this report is to address this item (i.e. the need Quality and for a ‘concept lake report’, as specified in the TOR). Reliability x Section 4 identifies issues, risks and performance criteria for the proposed lake (and associated water quality and reliability). Lake Water Yes 4.11 x Water balance modelling undertaken using 60-years of climate Balance data. x Results predict that water level variation will be minimal for developed catchment conditions. x Prior to the proposed development of the contributing catchment (to the proposed lake), additional (albeit temporary) sources of water (of appropriate quality) are anticipated to be required to prevent unacceptable water level variation. An average ‘top-up’ of 500m3/day would be required under existing catchment conditions to achieve an acceptable water level variation, with this required ‘top-up’ volume reducing as the catchment is developed. Amenity and Yes 4.4 & 4.5 Safety Lake Water Yes 4.10 Quality – Overall, Poor Water Quality and Dry Periods Rate of Yes 4.9 x During its operational phase, the rate of sedimentation in the lake Sedimentation is predicted to be minimal, with a maximum possible depth of accumulated sediment calculated (using MUSIC) to be approximately 0.011 m (or 11cm) over a period of fifty (50) years. Maintenance Yes 5 x Typical lake maintenance costs are estimated to be between Costs $391,000 and $522,000 per annum. It is noted that the costs will be refined as part of detailed design. Water Quality Yes Appendix C A monitoring program has been provided, and it has been proposed to Monitoring include: Program x Pre-development (baseline) water quality monitoring x Construction phase water quality monitoring x Operational phase water quality and sediment monitoring. Lake Yes Appendix D An indicative maintenance plan for the proposed lake has been Management provided. Plan \\aubne1fs09\G_Drive\admin-share\Admin\B21415.g.nc_Flinders Project\R.B21415.001.04.FlindersLakeConceptManagementPlan.docx Flinders Precinct 1: Concept Lake Management Plan iii Executive Summary Both the TOR and this plan recognise that more detailed investigations will need to be completed as part of subsequent Infrastructure Master Plans (IMP’s) and Overarching Site Strategy (OSS) to confirm that all of the identified criteria can be achieved in the long term. This plan should not therefore be considered the Detailed Lake Design Report, which is a separate but complimentary document to be developed during detailed design. However, based on previous experience and the best practice techniques proposed to manage water quality within the lakes, it is considered that meeting the performance criteria nominated in this report will be readily achievable in the long term. In particular, the issues associated with some existing lakes in south-east Queensland and Australia will be avoided by: x Adopting a lake depth that minimises the potential for stratification (although it is still intended to provide destratification devices in the lakes); x Treating runoff from developed areas to meet the water quality objectives nominated in the State Planning Policy prior to its discharge to the lakes; x Maintaining good water quality in the lakes by the recirculation (turnover) and treatment of water in the lakes using a combination of vegetated (natural) systems and physical treatment systems; and x Developing a comprehensive lake management and monitoring plan as part of further design and then implementing the plan in order to provide appropriate and regular maintenance of the lake rather than the ad-hoc approach adopted with respect to many waterbodies. The Flinders Precinct 1: Concept Lake Management Plan will be revised commensurate with the development of the Detailed Lake Design Report when further information is available. \\aubne1fs09\G_Drive\admin-share\Admin\B21415.g.nc_Flinders Project\R.B21415.001.04.FlindersLakeConceptManagementPlan.docx Flinders Precinct 1: Concept Lake Management Plan iv Contents Contents Executive Summary i 1 Introduction 1 1.1 Preamble 1 1.2 Proposed Development 1 1.3 General Lake Description 1 1.4 Report Objective and Limitations 3 1.5 Design and Operation Reference Materials 3 2 Site Description 4 2.1 Preamble 4 2.2 Site Location 4 2.3 Existing Land Usage 4 2.4 Topography, Drainage and Soils 4 2.5 Proposed Land Use 10 3 Lake Intent and Guiding Principles 12 3.1 Preamble 12 3.2 Intent for the Lake 12 3.3 Guiding Principles 13 4 Key Issues, Risks and Performance Criteria 14 4.1 Preamble 14 4.2 Identification of Issues 14 4.3 General Design, Construction and Establishment of Lake and Stormwater Treatment Devices 14 4.3.1 Risks 14 4.3.2 Performance criteria 15 4.4 Recreation, Amenity and Aesthetics 17 4.4.1 Risks 17 4.4.2 Performance criteria 20 4.5 Physical Hazards and Safety 22 4.5.1 Risks 22 4.5.2 Performance criteria 25 4.6 Lake Ecology 26 4.6.1 Risks 26 4.6.2 Performance criteria 28 G:\Admin\B21415.g.nc_Flinders Project\R.B21415.001.04.FlindersLakeConceptManagementPlan.docx Flinders Precinct 1: Concept Lake Management Plan v Contents 4.7 Climate Resilience 29 4.7.1 Risks 29 4.7.2 Performance criteria 29 4.8 Treatment of Stormwater Inflows 30 4.8.1 Risks 32 4.8.2 Performance criteria 32 4.9 Sedimentation 35 4.9.1 Risks 35 4.9.2 Performance criteria 36 4.9.3 Conceptual design verification 36 4.9.3.1 Operational phase 36 4.9.3.2 Construction phase 37 4.10 Lake Water Quality 38 4.10.1 Risks 38 4.10.2 Performance criteria 40 4.11 Lake Water Balance 41 4.11.1 Risks 41 4.11.2 Performance criteria 42 4.11.3 Conceptual design verification 43 4.11.3.1 Additional ‘Top-Up’ Water 43 4.11.3.2 Lake water balance and climate change 43 4.12 Lake Residence Time 44 4.12.1 Risks 44 4.12.2 Performance criteria 45 4.12.3 Conceptual design verification 46 4.13 Lake Mixing 48 4.13.1 Risks 48 4.13.2 Performance criteria 49 4.14 Flooding 49 5 Lake Management 50 6 References 51 Appendix A Terms of Reference A-1 Appendix B