Bristol City Council Bristol Avon Flood Strategy Strategic Outline Case Technical Document DRAFT for consultation October 2020 Better protecting people and property from flooding Future-proofing Bristol and neighbouring communities; enabling a greener, more active city; and unlocking our city’s potential. Bristol City Council (supported by Environment Agency) Bristol Avon Flood Strategy Ove Arup and Partners Strategic Outline Case Technical Document – October 2020 Consultation Draft Table of Contents 1 Executive Summary ........................................................................................................................................... 2 1.1 Strategy objectives .................................................................................................................................... 2 1.2 Strategic case ............................................................................................................................................ 2 1.3 Economic case .......................................................................................................................................... 5 1.4 Commercial case ....................................................................................................................................... 7 1.5 Financial case .......................................................................................................................................... 8 1.6 Management case...................................................................................................................................... 8 2 Strategic Case ................................................................................................................................................... 11 2.1 Introduction ............................................................................................................................................ 11 2.2 Need for intervention .............................................................................................................................. 15 2.3 Supporting development ......................................................................................................................... 17 2.4 Aligned business strategies ..................................................................................................................... 18 2.5 Environment and other considerations ................................................................................................... 21 2.6 Other sources of flooding ....................................................................................................................... 22 2.7 Strategic objectives ................................................................................................................................. 23 2.8 Current arrangements.............................................................................................................................. 23 2.9 Main benefits .......................................................................................................................................... 28 2.10 Main risks ............................................................................................................................................... 29 2.11 Constraints .............................................................................................................................................. 30 2.12 Dependencies .......................................................................................................................................... 30 2.13 Interfaces with other projects .................................................................................................................. 31 3 Economic Case .................................................................................................................................................. 37 3.1 Introduction ............................................................................................................................................ 37 3.2 Appraisal boundaries .............................................................................................................................. 37 3.3 Critical success factors ........................................................................................................................... 37 3.4 Long list options ..................................................................................................................................... 38 3.5 Shortlist options ...................................................................................................................................... 41 3.6 Non-financial benefits appraisal ............................................................................................................. 52 3.7 Preferred option ...................................................................................................................................... 52 3.8 Environmental compliance ..................................................................................................................... 55 3.9 Residual risk ........................................................................................................................................... 58 4 Commercial Case .............................................................................................................................................. 62 4.1 Roles ....................................................................................................................................................... 62 4.2 Regeneration and Development .............................................................................................................. 62 4.3 Maintenance ............................................................................................................................................ 62 4.4 Phasing Plan ........................................................................................................................................... 63 4.5 Procurement Strategy.............................................................................................................................. 64 bristol.gov.uk/bristolavonflood 1 Bristol City Council (supported by Environment Agency) Bristol Avon Flood Strategy Ove Arup and Partners Strategic Outline Case Technical Document – October 2020 Consultation Draft 4.6 Contractual terms and risk allocation ..................................................................................................... 65 4.7 Procurement route and timescales .......................................................................................................... 65 4.8 Efficiencies and commercial issues ........................................................................................................ 65 5 Financial Case ................................................................................................................................................... 67 5.1 Financial summary.................................................................................................................................. 67 5.2 Funding Sources ..................................................................................................................................... 70 6 Management Case ............................................................................................................................................ 76 6.1 Introduction ............................................................................................................................................ 76 6.2 Phase 1 management............................................................................................................................... 76 6.3 Project management................................................................................................................................ 76 6.4 Alternative delivery approaches ............................................................................................................. 82 6.5 Next steps ............................................................................................................................................... 85 Glossary ..................................................................................................................................................................... 86 Key supporting documents ...................................................................................................................................... 89 Appendix A ................................................................................................................................................................ 90 Appendix B ................................................................................................................................................................ 91 Appendix C ................................................................................................................................................................ 92 Appendix D ................................................................................................................................................................ 93 Appendix E ...............................................................................................................................................................