Stormwater Management in the South Park Lands
Total Page:16
File Type:pdf, Size:1020Kb
Brown Hill and Keswick Creek Stormwater Project Stormwater Management in the South Park Lands Stage 1 - Feasibility Study ABN: 44 357 839 204 Kath Moore and Associates PO BOX 385 Oaklands Park SA 5046 PR Ph/Fax: (08) 8294 8224 Social Planning & Community Consultation Mobile: 0411 063 056 Email : [email protected] Brown Hill and Keswick Creek Stormwater Project Stormwater Management in the South Park Lands Stage 1 - Feasibility Study Brown Hill and Keswick Creek Stormwater Project Stormwater Management in the South Park Lands Stage 1 - Feasibility Study Principal Contacts Keith Downard Drew Jacobi January 2010 Ref No 20090214RA2B Document History and Status Rev Description Author Reviewed Approved Date A Draft for comment Various KD DJ 25 Jan 2010 B Final Various KD DJ 26 Feb 2010 © Tonkin Consulting 2009 This document is, and shall remain, the property of Tonkin Consulting. The document may only be used for the purposes for which it was commissioned and in accordance with the Terms of Engagement for the commission. Unauthorised use of this document in any form whatsoever is prohibited. Brown Hill and Keswick Creek Stormwater Project Stormwater Management in the South Park Lands Stage 1 - Feasibility Study 20090214RA2B.doc Revision: B i Table of Contents Executive Summary vi 1 Introduction 1 2 South Park Lands Landscape and Urban Design 2 2.1 South Park Lands Landscape Character 2 2.2 Land Zoning 2 2.3 Land Use 5 2.4 Key Values 6 2.5 Existing Vegetation 6 2.6 Significant Trees 7 2.7 Native Grasses 8 2.8 Revegetation 8 2.9 Land Form 9 2.10 Drainage and Creek Alignments 9 2.11 Circulation 11 2.12 Amenity 12 2.13 Biodiversity 13 2.14 Existing Services 13 3 Glenside Campus 16 3.1 Existing Stormwater Infrastructure 16 3.2 Existing Sewer 16 3.3 Proposals for the Glenside Campus 16 4 Previous Work and Current Initiatives 17 4.1 Flood Mitigation and Stormwater Management 17 4.2 Glenelg to Adelaide Park Lands Recycled Water Project 17 4.3 Adelaide City Council’s Community Land Management Plan for Victoria Park/Bakkabakkandi 18 4.4 Decisions of the Adelaide Park Lands Authority 18 4.5 Adelaide Park Lands Management Strategy 18 4.6 Glenside Campus 19 5 Community Consultation – Key Issues 20 5.1 Context 20 5.2 Key Issues and Opportunities 21 Brown Hill and Keswick Creek Stormwater Project Stormwater Management in the South Park Lands Stage 1 - Feasibility Study 20090214RA2B.doc Revision: B ii 5.3 Desired Landscape Characteristics 23 5.4 Location of the Temporary Water Storage Areas 23 5.5 Overall Most Desired Elements 24 5.6 Other Comments 25 6 Flood Mitigation Storage 26 6.1 Introduction 26 6.2 Design Criteria 26 6.3 Proposed Concept Overview 30 6.4 Hydrological Modelling 31 7 Project Opportunities 33 7.1 Landscape Principles 33 7.2 Project opportunities 34 7.3 Feasibility Outcomes 35 7.4 Glenside Campus 35 7.5 Victoria Park (Bakkabakkandi) 37 7.6 Park 20 (Kurrangga) 37 7.7 Parklands Creek, Unley 37 7.8 Outcome Summary 40 8 Hydrodynamic Modelling 41 8.1 Hydrodynamic Model 41 8.2 Modelling Approach 41 8.3 Tuflow Modelling Assumptions 43 8.4 South Park Lands Models 43 8.5 Results 44 8.6 Comparison of Results with Previous Modelling 47 9 Stormwater Treatment and Harvesting Potential 48 9.1 Capability of a Scheme to Harvest Stormwater 48 9.2 Catchment Yield 48 9.3 Wetland Capacity 48 9.4 Aquifer Potential 49 9.5 Demand 52 9.6 Owner and Operator of a Scheme and Administrative Issues 53 9.7 Summary 53 10 Geotechnical Assessment 54 11 Heritage Assessment 56 Brown Hill and Keswick Creek Stormwater Project Stormwater Management in the South Park Lands Stage 1 - Feasibility Study 20090214RA2B.doc Revision: B iii 12 Stage 1 Environmental Assessment 58 12.1 Overview 58 12.2 Potentially Contaminating Activities 58 12.3 Previous Investigations 59 12.4 Conclusions and Recommendations 60 13 Planning Analysis 61 13.1 Introduction 61 13.2 Development Act 1993 61 13.3 Adelaide Park Lands Act 1995 62 13.4 Environment Protection Act 1993 63 13.5 Natural Resources Management Act 2004 63 13.6 Environment Protection and Biodiversity Conservation Act 1999 (Commonwealth) 64 14 References 65 Tables Table 6.1 100 year ARI Hydrological Scenarios 30 Table 6.2 100 year ARI (Early concept) Hydrological Model results 32 Table 8.1 Roughness Coefficients 42 Table 8.3 Concept Design 100 year ARI Performance Summary 44 Table 9.1 Potential Water Quality Improvement 49 Table 12.1 Potentially Contaminating Activities 58 Figures Figure 2.1 Study Area 3 Figure 2.2 Existing Stormwater Drainage 10 Figure 2.3 Existing Services 15 Figure 6.1 Parklands Creek (existing condition) Hydraulic Longitudinal Profile 27 Figure 6.2 Parklands Creek (with upgrades) Hydraulic Longitudinal Profile 28 Figure 6.3 Creek Capacity Issues 29 Figure 7.1 Concept Plan - Overview 36 Figure 7.2 Concept Plan – Glenside Campus and Victoria Park (Bakkabakkandi) 38 Figure 7.3 Concept Plan – Park 20 (Kurrangga) 39 Figure 8.1 Existing 100 Year ARI Flood Plain 45 Figure 8.2 Concept Design 100 Year ARI Flood Plain 46 Figure 9.1 Hallett Cove Sandstone & Existing Wells 50 Brown Hill and Keswick Creek Stormwater Project Stormwater Management in the South Park Lands Stage 1 - Feasibility Study 20090214RA2B.doc Revision: B iv Appendices Appendix A Brown Hill and Keswick Creek Flood Mitigation Study South Park Lands Basins Plans and Details Appendix B Victoria Park/Bakkabakkandi Community Recreation Park Concept Master Plan – Outline Plan Appendix C Glenside Site Master Plan Appendix D Wetland Concept Design and Wetland Planting and Landscaping Plan Glenside Campus Glenside Appendix E List of Project Stakeholders Appendix F Fact Sheets Appendix G Interview Template Appendix H Feedback Form Template Brown Hill and Keswick Creek Stormwater Project Stormwater Management in the South Park Lands Stage 1 - Feasibility Study 20090214RA2B.doc Revision: B v Executive Summary This study has been commissioned by the City of Unley, acting as the contracting party for the Brown Hill and Keswick Creek Stormwater Project to undertake investigations and design development for a series of flood mitigation storages, wetlands and aquifer storage and recovery (ASR) in the South Park Lands. The Stormwater Project is an initiative of the Cities of Unley, Adelaide, Burnside and West Torrens to progress stormwater projects set out in the Brown Hill and Keswick Creeks Flood Mitigation Study - Flood Management Master Plan which has been approved by the Stormwater Management Authority as a Stormwater Master Plan under the provisions of the Local Government (Stormwater Management) Amendment Act 2006. This report summarises the findings and key outcomes resulting from Stage 1 - Feasibility Study. The flood storages in the South Park Lands are an integral component of the catchment wide flood management master plan for the Brown Hill and Keswick Creek system and are one of a series of measures, including other flood storages and capacity upgrades that will, when completed in conjunction with those other measures, significantly reduce the risk of flooding in the catchments of both Creeks. Flood detention in the South Park Lands has been consistently proposed in many of the flood mitigation studies undertaken for the Brown Hill and Keswick Creeks catchments over the last few decades and a holistic solution to flooding would be compromised if the South Park Lands option does not proceed. The temporary flood storages in the South Park Lands proposed in the Brown Hill and Keswick Creeks Flood Mitigation Study - Flood Management Master Plan consist of 6 separate storages between Peacock Road and Fullarton Road. These proposals were constrained by the use of Victoria Park for horse racing. Since they were developed horse racing has ceased at Victoria Park and the City of Adelaide has commenced the implementation of a master plan to redevelop Victoria Park. This plan includes the establishment of wetlands on the northern side of Parklands Creek in the southern precinct of Victoria Park. This redevelopment allows for the original proposals for a relatively small storage in Victoria Park to be reassessed in light of the current plans for the Park. Hydraulic and hydrological modelling undertaken as a part of this current study has indicated that the hydrological performance of flood storages in the South Park Lands can be achieved by the establishment of temporary flood storages in three areas being: • An enlargement to the existing basin in the Glenside Campus that limits the flow into the South Park Lands during a 100 year storm, to within the capacity of the existing culvert under the Fullarton and Greenhill Roads intersection. • Creation of storage generally above and adjacent to the wetlands proposed to be constructed as part of the Victoria Park Master Plan. • Construction of a levee to create storage in the southern and western part of Park 20, which is located between Peacock and Unley Roads. These flood storages will limit the outflow of Parklands Creek from the South Park Lands to a peak flow of less than 10 m3/s during a 100 year storm event. Hydrodynamic floodplain modelling and mapping has confirmed that the concepts developed to date achieve this objective. This flow rate will require the augmentation of the existing culverts under Greenhill Road and the culvert at Young Street in Unley. It follows that these augmentation works should be part of the construction phase for the project. In addition further work is recommended to develop a strategy for works required in the creek channels through Unley and Wayville. This is considered to be necessary to ‘fill in the gaps’ between other strategic elements, namely the Park Lands detention storages, Creek diversion drains, and capacity upgrades to Glen Osmond Creek.